Category Archives: Wisconsin Stem Cells

What are embryonic stem cells? All embryonic stem cells are undifferentiated cells that are unlike any specific adult cell. However, they have the ability to form any adult cell. Because undifferentiated embryonic stem cells can proliferate indefinitely in culture, they could potentially provide an unlimited source of specific, clinically important adult cells such as bone, muscle, liver or blood cells.

Where do embryonic stem cells come from? Human embryonic stem cells are derived from in vitro fertilized embryos less than a week old. These embryos were produced for clinical purposes, but were no longer wanted for implantation by the couples who donated them. They were donated specially for this project with the informed consent of donors. In virtually every in vitro fertilization clinic in the world, surplus embryos are discarded if they are not donated to help other infertile couples or for research. The research protocols were reviewed and approved by a UWMadison Institutional Review Board, a panel of scientists and medical ethicists who oversee such work.

Why are they important? Embryonic stem cells are of great interest to medicine and science because of their ability to develop into virtually any other cell made by the human body. In theory, if stem cells can be grown and their development directed in culture, it would be possible to grow cells of medical importance such as bone marrow, neural tissue or muscle.

What, precisely, has the UW team accomplished? Scientists have been attempting to isolate and culture human embryonic stem cells for more than a decade. Using 14 blastocysts obtained from donated, surplus embryos produced by in vitro fertilization, the Wisconsin group established five independent cell lines. The cell lines, derived from preimplantation stage embryos, were capable of prolonged, undifferentiated proliferation in culture and yet maintained the ability to develop into a variety of specific cell types, including neural, gut, muscle, bone and cartilage cells.

How might they be used to treat disease? The ability to grow human tissue of all kinds opens the door to treating a range of cell-based diseases and to growing medically important tissues that can be used for transplantation purposes. For example, diseases like juvenile onset diabetes mellitus and Parkinsons disease occur because of defects in one of just a few cells types. Replacing faulty cells with healthy ones offers hope of lifelong treatment. Similarly, failing hearts and other organs, in theory, could be shored up by injecting healthy cells to replace damaged or diseased cells.

Are there other potential uses for these cells? The first potential applications of human embryonic stem cell technology may be in the area of drug discovery. The ability to grow pure populations of specific cell types offers a proving ground for chemical compounds that may have medical importance. Treating specific cell types with chemicals and measuring their response offers a short-cut to sort out chemicals that can be used to treat the diseases that involve those specific cell types. Ramped up stem cell technology would permit the rapid screening of hundreds of thousands of chemicals that must now be tested through much more time-consuming processes.

What can these cells tell us about development? The earliest stages of human development have been difficult or impossible to study. Human embryonic stem cells will offer insights into developmental events that cannot be studied directly in humans in utero or fully understood through the use of animal models. Understanding the events that occur at the first stages of development has potential clinical significance for preventing or treating birth defects, infertility and pregnancy loss. A thorough knowledge of normal development could ultimately allow the prevention or treatment of abnormal human development. For instance, screening drugs by testing them on cultured human embryonic stem cells could help reduce the risk of drug-related birth defects.

If a cluster of these cells was transferred to a woman, could a pregnancy result? No. These cells are not the equivalent of an intact embryo. If a cluster of these cells was transferred to a uterus, they would fail to implant, and would fail to develop into a fetus.

Is stem cell research the same as cloning?No. Stem cell research aims to develop new life-saving treatments, and cannot be used to develop a human being. Embryonic stem cells derived from the inner cell mass of an early-stage embryo cannot give rise to a placenta, so a human being could not develop, even if the stem cells were implanted into a womans uterus.

Why not derive stem cells from adults?There are several approaches now in human clinical trials that utilize mature stem cells (such as blood-forming cells, neuron-forming cells and cartilage-forming cells). However, because adult cells are already specialized, their potential to regenerate damaged tissue is very limited: skin cells will only become skin and cartilage cells will only become cartilage. Adults do not have stem cells in many vital organs, so when those tissues are damaged, scar tissue develops. Only embryonic stem cells, which have the capacity to become any kind of human tissue, have the potential to repair vital organs.

Studies of adult stem cells are important and will provide valuable insights into the use of stem cell in transplantation procedures. However, only through exploration of all types of stem cell research will scientists find the most efficient and effective ways to treat diseases.

What are the benefits of studying stem cells?Pluripotent stem cells represent hope for millions of Americans. They have the potential to treat or cure a myriad of diseases, including Parkinsons, Alzheimers, diabetes, heart disease, stroke, spinal cord injuries and burns.

This extraordinary research is still in its infancy and practical application will only be possible with additional study. Scientists need to understand what leads cells to specialization in order to direct cells to become particular types of tissue. For example, islet cells control insulin production in the pancreas, which is disrupted in people with diabetes. If an individual with diabetes is to be cured, the stem cells used for treatment must develop into new insulin-producing islet cells, not heart tissue or other cells. Research is required to determine how to control the differentiation of stem cells so they will be therapeutically effective. Research is also necessary to study the potential of immune rejection of the Cells, and how to overcome that problem.

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Embryonic Stem Cell Fact Sheet - University of WisconsinMadison

Valter Longo grew up in a village in Calabria called Molochio, famous for being a so-called blue zone an area where the locals were known to live exceptionally long lives and to suffer lower rates of chronic disease.

In recent years, the towns abundance of centenarians has become a curiosity for the likes National Geographic and what has emerged is a story of people who eating mainly beans and fruit, and no red meat.

And, in frequent harder times, they barely ate at all.

Perhaps it was all those ancient people that freaked young Valter Longo out. As a teenager he fled to the US, where he lived with extended family and planned on being a rock star.

But he eventually abandoned his guitar and took up studying those old home-town people and asking why they have managed to live longer and healthier lives than most and along the way hes become a rock star in the somewhat controversial field of slowing down ageing.

A paper he wrote in 1994 that detailed the ageing pathway of yeast was rejected and even mocked for seven years. It was eventually published in 2001.

As an enthusiastic 2017 profile in Stat News reported, the paper has since been cited hundreds of times.

If someone said, What are you working on? we would say oxidative chemistry, Dr Longo told Stat. You couldnt say ageing. That was viewed as a joke.

Some theorists, such as the British molecular biologist Aubrey de Grey, believe ageing is a disease that can be cured. Once thats achieved we could live to 1000 years, is de Greys contentious claim.

Dr Longo professor of gerontology and the biological sciences at the USC Davis School of Gerontology and director of the USC Longevity Institute is more modest in his ambitions. Hes has become convinced that diet is the key to living vigorously to the age of 110.

By way of contrast, he pointed out in his 2016 Ted Talk that if we could completely cure cancer, the gains in longevity would be relatively modest, maybe an extra four or five years on average.

Where Aubrey de Grey is something of a superstar in the immortality sphere, his ideas have been written off by many serious scientists.

Professor Longo, on the other hand, has convinced many of his colleagues that hes truly on to something. Even sceptics have suggested his ideas are plausible, but want to see larger studies in humans.

In April, Professor Longo having been in the pursuit of longevity for 30 years co-authored a widely reported article with Dr Rozalyn Anderson, director of the metabolism of ageing program at the University of Wisconsin school of medicine and public health.

The researchers reviewed hundreds of studies on nutrition, diseases and longevity in laboratory animals and humans and combined them with their own studies on nutrients and ageing.

The net result was a clearer picture of the best diet for a longer, healthier life.

We explored the link between nutrients, fasting, genes and longevity in short-lived species, and connected these links to clinical and epidemiological studies in primates and humans including centenarians, Professor Longo said.

By adopting an approach based on over a century of research, we can begin to define a longevity diet that represents a solid foundation for nutritional recommendations and for future research.

The short version: Lots of legumes, whole grains, and vegetables; some fish; no red meat or processed meat and very low white meat; low sugar and refined grains; good levels of nuts and olive oil, and some dark chocolate.

In fact, this is essentially the diet that Professor Longo previously published in book form but now the science is catching up.

On the face of it, it doesnt appear to be that ground-breaking.

But the innovation isnt in the foods you consume most of the time under the plan, the life-extending potential is in whats called a fasting-mimicking diet.

Its a rather neat trick, where the body goes into fasting mode for five days which prompts stem cells to regenerate the immune system while you actually continue to eat a modest number of calories.

The Longo plan includes eating 1100 plant-based calories made up of nuts, vegetables, soups, olive and teas on the first day and then around 800 for the next four days.

In 2017, Professor Longo and colleagues published a randomised Phase II clinical trial involving 71 healthy people aged 20 to 70.

On and off, for three months, the participants followed a periodic, five-day fasting diet designed by Longo.

The diet reduced cardiovascular risk factors including blood pressure, signs of inflammation (measured by C-reactive protein levels), as well as fasting glucose and reduced levels of IGF-1, a hormone that affects metabolism.

It also shrank waistlines and resulted in weight loss, both in total body fat and trunk fat, but not in muscle mass.

Overall, the diet reduced the study participants risks for cancer, diabetes, heart disease and other age-related diseases.

These positive results were found to be sustained three months after the trial.

What happens next? A large, FDA phase III clinical trial to test the fast-mimicking diet on patients diagnosed with age-related diseases or at high risk for them.

Professor Longo might be a very old man by the time he fully cracks the code for the longevity. By then, hell be walking proof of his own theories. Or not.

For more on Professor Longo and fast-mimicking might slow ageing, see here.

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The longevity diet: Lots of beans and periodic fasts slow ageing - The New Daily

Tracing features in a large 3D electron microscopy dataset reveals a zebrafish blood stem cell (in green) and its surrounding niche support cells, a group photo method that will help researchers understand factors that contribute to blood stem cell health which could in turn help develop therapies for blood diseases and cancers. Image by Keunyoung Kim.

MADISON For the first time, researchers can get a high-resolution view of single blood stem cells thanks to a little help from microscopy and zebrafish.

Researchers at the University of WisconsinMadison and the University of California San Diego have developed a method for scientists to track a single blood stem cell in a live organism and then describe the ultrastructure, or architecture, of that same cell using electron microscopy. This new technique will aid researchers as they develop therapies for blood diseases and cancers.

Currently, we look at stem cells in tissues with a limited number of markers and at low resolution, but we are missing so much information, says Owen Tamplin, an assistant professor in UWMadisons Department of Cell & Regenerative Biology, a member of the Stem Cell & Regenerative Medicine Center, and a co-author on the new study, which was published Aug. 9 in eLife. Using our new techniques, we can now see not only the stem cell, but also all the surrounding niche cells that are in contact.

The niche is a microenvironment found within tissues like the bone marrow that contain the blood stem cells that support the blood system. The niche is where specialized interactions between blood stem cells and their neighboring cells occur every second, but these interactions are hard to track and not clearly understood.

As a part of the new study, Tamplin and his co-lead author, Mark Ellisman, a professor of neuroscience at UC San Diego, identified a way to integrate multiple types of microscopic imaging to investigate a cells niche. With the newly developed technique that uses confocal microscopy, X-ray microscopy, and serial block-face scanningelectron microscopy, researchers will now be able to track the once elusive cell-cell interactions occurring in this space.

This has allowed us to identify cell types in the microenvironment that we didnt even know interacted with stem cells, which is opening new research directions, Tamplin says.

As a part of this study, Tamplin, and his colleagues, including co-first authors Sobhika Agarwala and Keunyoung Kim, identified dopamine beta-hydroxylase positive ganglia cells, which were previously an uncharacterized cell type in the blood stem cell niche. This is crucial, as understanding the role of neurotransmitters like dopamine in regulating blood stem cells could lead to improved therapeutics.

Transplanted blood stem cells are used as a curative therapy for many blood diseases and cancers, but blood stem cells are very rare and difficult to locate in a living organism, Tamplin says. That makes it very challenging to characterize them and understand how they interact and connect with neighboring cells.

While blood stem cells are difficult to locate in most living organisms, the zebrafish larva, which is transparent, offers researchers a unique opportunity to view the inner workings of the blood stem cell niche more easily.

Thats the really nice thing about the zebrafish and being able to image the cells, Tamplin says of animals transparent quality. In mammals, blood stem cells develop in utero in the bone marrow, which makes it basically impossible to see those events happening in real time. But, with zebrafish you can actually watch the stem cell arrive through circulation, find the niche, attach to it, and then go in and lodge there.

While the zebrafish larva makes it easier to see blood stem cell development, specialized imaging is needed to find such small cells and then detail their ultrastructure. Tamplin and his colleagues spent over six years perfecting these imaging techniques. This allowed them to see and track the real-time development of a blood stem cell in the microenvironment of a live organism, then zoom in even further on the same cell using electron microscopy.

First, we identified single fluorescently labeledstem cells bylight sheet or confocal microscopy, Tamplin says. Next, we processed the same sample forserial block-face scanningelectron microscopy. We then aligned the 3D light and electron microscopy datasets. Byintersecting these different imaging techniques,we could see the ultrastructure of single rare cells deep inside a tissue. This also allowed us to find all the surrounding niche cellsthat contact a blood stem cell. We believe our approach will be broadly applicable for correlative light and electron microscopy in many systems.

Tamplin hopes that this approach can be used for many other types of stem cells, such as those in the gut, lung, and the tumor microenvironment, where rare cells need to be characterized at nanometer resolution. But, as a developmental biologist, Tamplin is especially excited to see how this work can improve researchers understanding of how the blood stem cell microenvironment forms.

I think this is really exciting because we generate all of our blood stem cells during embryonic development, and depending on what organism you are, a few hundred or maybe a few thousand of these stem cells will end up producing hundreds of billions of new blood cells every day throughout your life, Tamplin says. But we really dont know much about how stem cells first find their home in the niche where theyre going to be for the rest of the life of the organism. This research will really help us to understand how stem cells behave and function. A better understanding of stem cell behavior, and regulation by surrounding niche cells, could lead to improved stem cell-based therapies.

This research was supported by grants from the National Institutes of Health (R01HL142998, K01DK103908, 1U24NS120055-01, R24 GM137200) and the American Heart Association (19POST34380221).

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See-through zebrafish, new imaging method put blood stem cells in high-resolution spotlight - University of Wisconsin-Madison

In the early nineties, Jacques Galipeau was outside his native Canada, training at the Tufts New England Medical Center in Boston. It was an exciting time to be a young hematologist. The dream of gene therapy was becoming a reality, and with it came the promise of potential cures for the likes of sickle cell disease and thalassemia.

Fast forward, and we find a man who has ascended to lofty heights. At the recent 2022 meeting of the International Society for Cell & Gene Therapy, Galipeau was crowned as its new president. Here, we quiz Galipeau about the present and future of advanced medicine.

Well, the field has matured since the early nineties. Its worth remembering that the proof-of-concept for applying cell and gene therapies in humans arrived more than 30 years ago. Now, we have approved products! The first live cell vaccine approved by the FDA was Provenge in 2010. More recently, weve had the whole CAR T story, and in Europe weve seen the approval of mesenchymal cells for Crohns-related skin complications. All in all, its a very nice buffet.

As Im university based, my work is in discovery understanding how cells tick and how to make a better mousetrap out of them. We also work more boldly, testing first-in-human studies that may grow legs and march toward further development. At the University of Wisconsin-Madison, we have a special interest in virus-specific T cells and the version 2.0 of mesenchymal cells. As a scholar, these are my particular specialisms.

While wearing my ISCT hat, on the other hand, Im like a kid locked in a candy shop! There are so many exciting, emerging, and improved platforms, especially in immunotherapy and regenerative medicine. For some, the latter term is a dirty word because it has so often been bandied about as a catch-all everything for everybody. But now, were hearing about ongoing works like the clinical trials of induced pluripotent stem (IPS) cell-derived dopaminergic neurons for Parkinson's disease an excellent example of a highly promising regenerative medicine.

Regenerative medicines are replacement therapies, but the definition has now broadened to include all somatic cell therapies. Historically, regenerative medicine was all about stem cells, but more recently we have realized that there are many cells and tissues that can be used as living therapeutics, while having nothing to do with stem cells. For example, lymphoid cells and live tumor cell vaccines.

Absolutely. We humans are gregarious simians. Chimps dont talk its all nonverbal. Humans deal in a great deal of nonverbal communication too, and that cant be replicated online. So much of the spontaneity and exchange is leached away through the virtual interface. Not to mention the drop in dopamine levels!

Offline serendipity cant be replicated either. Everybody has a story that proves it. You turn and say hello to the person behind you in a queue for lunch at an event, and the next thing you know youre launching a collaboration. That doesnt happen on Zoom, where everyone is just one rectangle in a grid of video feeds.

It was a bold bet. Between our CEO Queenie Jang, our outgoing president Bruce Levine, and myself, we knew that we would have to make the call by October 2021. Reading the signs, we made plans for an in person event, and the result was a smashing success the biggest turnout weve ever had at an international meeting. I also think it helped prove that in-person events should remain the gold standard, with virtual hybridity as a bonus that remains well worth considering. Recording events is another pandemic practice wed like to keep alive. Having those recordings for future reference and wider access is really valuable. We want these international events to be absolutely optimal because they only come once per year and attending them isnt cheap especially for our friends flying in from afar!

We all know workforce development is an emerging topic, but I was surprised by just how strong the appetite for and imperative from stakeholders was. Had I not attended in person, I never would have got that impression.

From the perspective of platforms, I was surprised by the explosion of clinical-stage startups in cancer immunotherapy. Back in old school advanced therapy, the only way you could modify immune effector cells was using retroviral vectors. But now, we are seeing an explosion of emerging disruptive platforms that could be game changers as far as nimbleness is concerned.

Our societys focus on translational manufacturing, regulations, and first-in-human trials really sets us apart. In those areas, the technologists working in the field are really important. Theres a whole army of them. Thats why, at ISCT this year, we had a day for the technologists Saturday, to be precise.

It was standing room only! And it was great to see such a real uptick in attendance from people who are in neither business nor science. These are the people who really do the up-close work, and we learned that they have a real hunger for networking, change, and best practices. The ISCT is a knowledge-transfer organization, so we are more than happy to sate these appetites.

Last of all, Ill mention the real explosion of interest in exosomes as a therapeutic modality. Its lending a second life to the already popular interest in mesenchymal cells. Depending on how you tickle them in the petri dish, they spit out exosomes through which many of their functional attributes are transferred to tissues. This is a brand new development that is taking off in parallel with cancer immunotherapy, replacement therapy, and IPS.

I think the answer will be woven from different strands. In the case of established, approved, effective approaches that rinse, wash, and repeat 1000 times in a row, automation is your most obvious ally. But when youre still carrying out investigational development when youre building the plane as you fly it you may need some hands! Lab work can be a science in the same way cooking is a science. You need tactility, and more than a little artistry.

You really cannot underestimate the importance of having hands and being human! Take the analogy of baking a chocolate cake. I might give the exact same recipe to Bob and to Bert. Bob makes a beautiful cake, and Bert makes a burnt mess. Good hands and good instincts; some people have them, and some people just dont.

Compounding that, so many of our platforms are not set in stone. Disruptive technologies are loose in this field, and the task of incorporating and optimizing them is a hands-on affair. And thats where the workforce comes in. ISCT pays a great deal of attention here because we excel as a knowledge transfer and networking organization. Were not a university we cant confer diplomas but the way we pass on best practices and knowhow does make us serve as a sort of cooking school, if I may stretch my chocolate cake metaphor a little further.

We bring in domain experts that understand the obstacles and the friction points, and introduce them to newbies people who may well be very clever and have excellent degrees, but who still need to learn the ropes, and how to avoid beginners mistakes. Of course, you cant stop after initiation. This is an ever-evolving field of ever-evolving platforms. Penning a curriculum is not much use because it will likely be out of date by the time youve completed the first draft.

At ISCT events, we dont try to operate as a substitute for universities or technical colleges, as thats not our remit. Rather than disseminating knowledge through lecturing, we use a roundtable format. We set up a panel of experts, sit them down together, and let the audience listen to their back-and-forth in real time. Its an extremely valuable way to educate people on topics that wont appear in print for another year. In short, our attendees walk away as slightly more developed and informed professionals.

Right now, everybody is focusing on the highly impactful cell therapeutic platforms that have met marketing approval and are now commercially deployed. This is especially true in the case of cancer immunotherapy space, and even for Takedas mesenchymal product, Alofisel. The challenges here really hinge on the different regulatory environments that shape them.

In Europe, deployment and commercial success is dictated predominantly by universal payers and national entities. The US will be more of a wild west as far as pricing and reimbursement are concerned. I have no magic solutions for my commercial friends, but I do aim to help them understand the best practices that can ensure both ROI, as well as the sustainability and deployability necessary for distributive justice. Balancing ROI and access is not just a moral question; if one overtakes the other, the platform may collapse. Over time, competition ought to bring the current prices down. As more products are rolled out and sorted according to their effectiveness, potency, and ability to improve human outcomes, it is my hope and expectation that they will position themselves in a sustainable manner.

That said, I am currently very interested in another aspect that complements pharmas traditional central manufacturing, hub-and-spoke model: the democratization of advanced cell therapy, manufacture, and deployment. Bone marrow transplants serve as a good example. These are cell therapies, but since regulation does not define them as an advanced cell therapy, they do not require oversight by the EMA or FDA. Everything from cell collection and manipulation to re-administration is carried out in academic health centers. Industry had no direct involvement in the development of bone marrow transplants.

Now, with the explosion of cell therapies, the relevant technologies are becoming increasingly simple, and the prices are ever more robust. It is becoming easier to imagine that hospitals and other places of care could serve as a complement to large-scale manufacturing, especially for autologous cell therapies or one patient/one donor paradigms. There's a lot of new money in this space geared toward not only the traditional model, but also these complementary models of deployment. Thats something I think we need to face, as the future comes knocking.

Originally posted here:
ISCT's New Leader on the Future of Cell and Gene Therapy - The Medicine Maker

Erik Ranheim, MD, PhD, an academic physician with a distinguished record of achievement in medical education, will be the next chair of the University of Wisconsin School of Medicine and Public Healths Department of Pathology and Laboratory Medicine.

Emily Kumlien608-516-9154ekumlien@uwhealth.org

I am humbled, honored, and excited to lead an extraordinary group of clinicians, researchers, teachers, and staff, Ranheim says. I have been deeply committed to our department, UWMadison, and the greater Madison community for nearly 20 years, and look forward to pursuing excellence in all of our missions in a healthy and welcoming departmental environment.

Pathologists, technical, and professional staff in the department are at the forefront of diagnosing disease and ensuring proper treatment for patients, providing laboratory medicine services in anatomic pathology and clinical pathology for eight hospital and clinic-based laboratories. Anatomic pathologists in the department process 60,000 surgical and hematopathology specimens and 30,000 cytologies per year, and perform forensic and medical autopsies. Clinical pathologists and laboratory medicine staff conduct more than 3.8 million laboratory tests annually, analyzing bodily fluids such as urine, blood, plasma, and saliva using state-of-the-art technology.

The department is also home to a vibrant research portfolio and is ranked 16th in the nation for funding from the National Institutes of Health. Researchers have focused on topics including the immunology of infectious diseases, neuroimmunology, Alzheimers disease, cancer, glaucoma, and hematopoietic stem cells.

Ranheim completed his undergraduate degree at the University of Pennsylvania, followed by a PhD in immunology and MD at the University of Minnesota. He completed his residency training in anatomic pathology, fellowships in hematopathology and autopsy, and postdoctoral research fellowship at Stanford University.

Ranheim received the schools Deans Teaching Award and a Team Science Award from the Society for the Immunotherapy of Cancer. He has also been named Physician Citizen of the Year by the Wisconsin Medical Society, among other honors.

His background as a clinician, educator, and researcher with a systems-level view makes him highly qualified to step into this role, says Robert N. Golden, MD, dean of the UW School of Medicine and Public Health.

Dr. Ranheim is a deeply respected leader in our school and academic health system, he said. It is exciting to see him step into this important leadership role. He understands the remarkable synergies that are created through the integration of our research, education, and clinical missions.

Ranheims appointment will be effective in mid-August.

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Erik Ranheim to become chair of Department of Pathology and Laboratory Medicine - University of Wisconsin School of Medicine and Public Health

Aug 01, 2022 5:00 PM

Author: Doug Dollemore

Imagine a cure for diabetesa disease that afflicts one in 10 Americans. It might not happen in our lifetime, but the work of William Holland, PhD, an associate professor in the Department of Nutrition & Integrative Physiology at University of Utah Health, is accelerating us closer. Major institutions are taking note, and Holland recently achieved a rare feat in the world of academic research: three grant award notifications in a single day.

Diminishing Diabetes Complications

The first is a renewal of funding from the National Institute of Diabetes and Digestive and Kidney Diseases, through the National Institutes of Health. The $1,820,000 grant over the next four years supports Hollands efforts to explore how to reverse Type 1 diabetes.

While he was an assistant professor at University of Texas Southwestern Medical Center, Holland helped find that blocking a glucagon receptor in a Type 1 diabetic animal was curativeone injection in mice was sufficient to completely cure them of diabetes. The insulin producing beta cells grew back so quickly that the mice needed no further treatment.

Moving forward, Holland is trying to determine how that occurs so it can be translated safely to treatment of diabetes in humans, avoiding troublesome side effects like liver toxicity and hypertension.

If you can get just a fraction more insulin producing beta cells in a patient, that will greatly diminish a lot of the complications of diabetes, Holland said. If their insulin production works, it will help prevent hypoglycemic episodes, neuropathy, vascular disease, heart disease, and so on. Very few people die of diabetes; they die of complications of diabetes.

A Gene-ius Way to Predict Disease Vulnerability

The second grant is from the American Diabetes Association for $200,000 per year for three years. It will allow Holland to continue to research how to use genetics to provide precision therapies for individuals suffering from diabetes and heart disease.

Hyperceramidemia means your blood has too many lipids called ceramides. Research into the condition involves genetic sequencing to determine which genes regulate these toxic lipids that predict diabetes and heart disease.

Building off a collaboration with a colleague at the University of Wisconsin, Holland is studying multi-generational human genetic data from volunteers at the University of Utah. The Wisconsin collaboration demonstrated that small snippets of DNA can be used to identify ceramide levels based on a specific gene segment.

Today, Hollands team measures the ceramides and genetic sequencing of patients prone to disease. They examine the genes that were identified in a mouse to see if they correlate to disease and toxic lipid levels in humans.

One of the things you can get out of this is the ability to genotype a person to determine their risk for diabetes or heart disease in childhood, Holland said. If so, we can intervene to make sure that never becomes a problemlike avoiding a diet high in saturated fat.

During this research, Holland identified what he believes is the first case of familiar hyperceramidemia, a family with 64% of its members receiving dialysis. This family has a mutation in adiponectin, meaning they have a lesion in the gene that causes a high level of ceramide in their bloodstream.

Hollands team continues to determine if this genetic lesion results in high risk for diabetic kidney disease. The study of these rare genetic instances can help determine the drugs that might be useful for an entire class of people prone to diabetes.

Small Steps Toward a Big Cure

Finally, Holland received notification of a two-year research award from SymbioCellTech, LLC. This grant helps fund his labs research on transplanting and evaluating human neo-islets.

Islets are clusters of insulin-producing beta cells. When transplanted, they can release insulin to control blood glucose. SymbioCellTech is a biotechnology company based in Utah that is working to cure diabetes through a patented stem-cell therapy involving neo-islets.

This research will specifically benefit patients who are transplant recipientsa specific immune rejection which causes Type 1 diabetes also makes transplanted islets prone to immune destruction. Hollands collaboration with SymbioCellTech aims to help overcome this treatment barrier.

Perhaps most impressively, Holland is the principal investigator on all three of the grants that received over $2.7 million in total funding. He earned a PhD in biochemistry from the University of Utah and completed his degree research with Scott Summers, PhD, the current chair of the Department of Nutrition & Integrative Physiology. Like Summers, Holland is motivated to cure diabetes due to a history of the disease in his family: his mother and grandfather both suffered severe complications.

My goal is to change the limitations around diabetes detection and treatment, Holland said. I know how long everything takes, so my goal is to change the future for my children and nieces so they grow up with more health and less medicine.

Written by Sarah Shebek

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It's a Holland Hat Trick: College of Health Professor Gets Three Grant Notifications in One Day - University of Utah Health Sciences

This week, the White House held a summit on the future of Covid-19 vaccines that brought together scientists and vaccine manufacturers to discuss new vaccine technologies. Officials said that new vaccines are an urgent priority as US Covid-19 cases and hospitalizations are rising once again, vaccination rates are hitting a plateau, Covid-19 funding is running low, and the virus itself is continuing to mutate.

But in recent months, scientists have also learned that the immune cells that provide lasting protection known as memory B cells and T cells can keep the worst effects of the most recent versions of the virus at bay, even if they were trained to corral older strains of SARS-CoV-2. Vaccine researchers are expanding their focus from antibodies to these memory immune cells as the new discoveries open a path toward universal coronavirus vaccines.

Universal vaccines, however, are still a long way off possibly years drawing on approaches never used before. Thats a scientific challenge, said Anthony Fauci, chief medical adviser to the president, during the summit.

The good news is that far fewer people are dying from the disease compared to the wave of cases this past winter spurred by the omicron variant of SARS-CoV-2, the virus that causes Covid-19. The first round of Covid-19 vaccines is still holding death rates down to around 360 per day, according to the Centers for Disease Control and Prevention. Still, health officials want to do better.

While the vaccines are terrific, hundreds of Americans, thousands of people around the world are still dying every day, Ashish Jha, the White House Covid-19 response coordinator, said Tuesday. Building a new generation of vaccines will make an enormous difference to bringing this pandemic to an end.

The National Institutes of Health is already funding several research teams developing Covid-19 vaccines that elicit protection against many different versions of the virus, shield against future changes to the virus before they arise, and protect against other coronaviruses.

From there, health officials are aiming not just to develop vaccines that provide more durable protection against a wider array of threats, but also rethinking the vaccination strategy overall. With a better understanding of long-term immunity, more robust vaccines, and a comprehensive public health approach, health officials say they have a better shot at restoring normalcy.

Much of the discussion around vaccines and immunity to Covid-19 centers on antibodies, proteins produced by the immune system that attach to the virus. And indeed, they are important.

Antibodies that prevent the virus from causing an infection in the first place are called neutralizing antibodies. A high concentration of antibodies in the body that blocks SARS-CoV-2 is a key indicator of good protection against reinfection. Antibodies can also serve as a way to mark intruders so that other immune system cells can dispose of them.

But making large quantities of antibodies takes a lot of resources from the body, so their production tapers off with time after an infection or a vaccination. Another concern is that antibodies are very particular about where they attach to the virus. If the virus has a mutation at that attachment site called an epitope antibodies have a harder time recognizing the pathogen. Thats why some antibody-based treatments for Covid-19 are a lot less effective at stopping the omicron subvariants.

Fortunately, the immune system has other tools in its chest. Inside bone marrow lie stem cells that differentiate to become B cells and T cells. Together, they form the core of the adaptive immune system, which creates a tailored response to threats. After a virus invades a cell, it hijacks its machinery to make copies of itself. White blood cells known as cytotoxic T cells, a.k.a. killer T cells, can identify the wayward cell and make it self-destruct. This mechanism doesnt prevent infections, but it stops them from growing out of control.

Another type of T cell, called a helper T cell, acts as an on switch for B cells, which are the cells that manufacture antibodies. After an infection is extinguished, some T cells and B cells turn into memory cells that stick around in parts of the body, ready to rev up if a virus dares to show up again.

So far, the adaptive immune system seems to hold up pretty well. The first round of Covid-19 vaccines was targeted against the earliest versions of the virus, so plenty of vaccinated people have had breakthrough infections, especially from the newer variants. But only a tiny fraction of those immunized have fallen severely ill or have died.

That likely means that their immune systems couldnt keep the virus out entirely, but their immune cells were able to spool up once an infection took root.

Someones neutralizing antibodies may not be up to the task, but if they have the T cell response, that may make all the difference with severe disease, said Stephen Jameson, a professor of microbiology and immunology at the University of Minnesota.

In just the past year, many studies have borne out the significance of memory B cells and T cells for long-term Covid-19 immunity and answered critical questions about whether they can respond to new variants.

Researchers have found that lower levels of memory B cells were associated with a greater risk of breakthrough infections from the delta variant. On the other hand, B cells induced by Covid-19 vaccines could reactivate months out from the initial vaccine doses to churn out antibodies.

Similarly, scientists found that T cells generated by vaccines were able to recognize SARS-CoV-2 variants like omicron months later. These data provide reasons for optimism, as most vaccine-elicited T cell responses remain capable of recognizing all known SARS-CoV-2 variants, scientists wrote in a March paper in the journal Cell.

Another study showed that Covid-19 vaccines generated strong T cell memory that protected against the virus even without neutralizing antibodies. I think the immunological memory which is induced by vaccines is pretty good and is actually sustained, said Marulasiddappa Suresh, a professor of immunology at the University of Wisconsin-Madison who co-authored the study, published in the Proceedings of the National Academy of Sciences in May.

Whether this protection will hold up over the course of years remains to be seen. Experiences with past coronaviruses like MERS showed that antibodies to the virus can last for four years. Covid-19, however, is spreading at much higher levels and mutating more than MERS did during its initial outbreak. Future protection against the disease hinges on the immune system as well as how much the virus itself will change, and scientists are closely watching both.

Most vaccines to date are designed to counter one or a handful of versions of a given virus. They present the immune system with a target that allows it to prepare its defenses should the actual virus ever invade.

In the case of Covid-19, most vaccines coach the immune system to target the spike protein of the SARS-CoV-2 virus, which it uses to start the infection process. This helps the immune system generate strong neutralizing antibodies. But the spike protein is one of the fastest mutating parts of the virus, making it a moving target.

The fact that B cells and T cells have managed to hold off newer variants hints that it may be possible to target the virus in other ways. Rather than just making neutralizing antibodies that attach to the spike, the adaptive immune system could also produce non-neutralizing antibodies that bind to other regions of the virus that mutate very little, if at all. While these antibodies may not block an infection from taking root, they may be able to provide more durable protection against severe illness that holds up against future SARS-CoV-2 variants.

Another approach is to present the immune system with a variety of different potential mutations of a virus, allowing white blood cells to prepare a response to a spectrum of threats and fill in the blanks.

Universal vaccines have not been deployed before, so researchers are in uncharted territory, and the shots likely wont be ready ahead of a potential fall spike in Covid-19 cases. But developing such a vaccine could eventually reduce the need for boosters and give health officials a head start on countering future outbreaks.

In the meantime, US health officials are planning to distribute vaccines reformulated to target newer Covid-19 variants by September, but its not clear yet what the optimal strategy will be to deploy them given the wide range of immune protection across the population. Between infections and vaccinations, the majority of people in the country have had some exposure to the virus, granting some degree of protection. And since the adaptive immune response to Covid-19 seems to be robust in most people, it may not be necessary for everyone to get an additional shot.

One option is to seek out those with weaker immune systems for boosters. Researchers have now developed a rapid test to measure T cell responses to Covid-19 that could identify people who are more vulnerable to reinfections or breakthrough infections.

Though vaccines are absorbing the most severe consequences from Covid-19, infections are still proving disruptive. Covid-19 outbreaks are contributing to staffing shortages at hospitals, schools, and airlines, leading to delays and cancellations. And the more the virus spreads, the more opportunities it has to mutate in dangerous ways. Stopping this threat requires limiting infections, which in turn still demands measures like social distancing and wearing face masks.

So as good as the next generation of vaccines may prove to be, they are only one element of a comprehensive public health strategy for containing a disease.

The rest is here:
How long-term Covid-19 immunity paves the way for universal Covid-19 vaccines - Vox.com

In utero, an umbilical cord is the babys lifeline and after birth, it still has the potential to sustain life.

Rather than cutting the cord immediately, Dr. Dennis Costakos, neonatologist at Mayo Clinic Health System La Crosse, advocates for delaying clamping for 30 seconds to a minute to increase distribution of blood to the infant rather than leaving this precious blood in the placenta. Clamped at 10 to 15 seconds, 67% of the umbilical cord blood will go directly to the infant, a percentage that increases to 80% at the 60-second mark.

Costakos implemented delayed cord clamping at Mayo Clinic Health System in La Crosse in 2006 after presenting his research. The process has been around for hundreds of years but was not always common. In the 1960s, early cord clamping was the norm due to concerns about maternal and infant outcomes, but studies over the decades led to making delayed clamping standard some 50 years later.

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For babies born at full term, the extra blood can improve iron stores and may enhance development.

Dennis Costakos

For babies born prematurely, waiting to clamp can decrease risk of some potentially life threatening complications of being born earlier than full term. Both the American College of Obstetricians and Gynecologists Committee on Obstetric Practice and the American Academy of Pediatrics recommend delayed cord clamping, with a 2012 systematic review of 15 studies showing a wait of 30 to 180 seconds had significant health benefits for preterm infants.

Among the infants studied, cord blood was found to improve transitional circulation and red blood cell volume, and reduce the chances of necrotizing enterocolitis (inflammation of intestinal tissue) and intraventricular hemorrhage.

It is possible there will be enough cord blood to both stay with the baby and be saved or donated. The cord blood can be stored in a private bank for use to help a family member with a qualifying condition, or donated to a public cord blood bank to aid in treating others.

If a sibling is currently suffering from leukemia, sickle cell disease, Hodgkins lymphoma or thalassemia, physicians may after discussion with the siblings care team and looking at the best treatment options recommended saving it for the sister or brother.

Cord blood banking for personal use is not recommended, as it is a highly costly service up to $2,000 to start, and additional fees of around $100 annually and not covered by insurance. The chance that the baby may later need their own stems cells is miniscule, and if requiring medical intervention a donors stem cells would likely be used.

The chances that you would ever call for the cord blood would not be more than one in 10,000, maybe even as low as one in 250,000, Costakos says.

Donations, according to the Health Resources and Services Administration, are in need. Around 70% of patients do not have a fully matched family member, and for them A transplant of bone marrow or cord blood from an unrelated donor may be their only transplant option. The National Cord Blood Inventory aims to collect and store at least 150,000 new cord blood units, with donations from members of diverse racial and ethnic groups especially needed.

Donating, however, may not be feasible. Costakos notes moms-to-be could be disqualified from donating to public banks due to existing health conditions, and travel would be necessary as there are no collection centers in Wisconsin and Minnesota.

Should they opt in to bank or donate, parents must express their wishes to save the cord blood in advance. The collection process is painless for the baby, Costakos says, as there are no nerve fibers in the umbilical cord.

Blood is drained from the umbilical cord with a needle, and a special collection bag is attached, Costakos says. After the bag is sealed, the placenta is delivered. The process takes about 10 minutes.

In some cases, immediate cord clamping may be necessary, such as if the cord placenta has already separated from the baby. This condition, called abruptio placenta, can interrupt or prevent oxygen and nutrient supply to the baby and cause the mother to bleed excessively.

For more information on cord blood donation, visit https://bloodstemcell.hrsa.gov/.

UW-La Crosse staff and faculty deliver gift baskets Tuesday afternoon at Gundersen.

Donations from the UW-L campus community are delivered at Gundersen.

Nurses and a representative from the Gundersen Medical Foundation met the UW-L students and faculty.

Donations from the UW-L campus community are delivered at Gundersen.

The gifts including snacks, games, gift cards, thank-you notes and more were donated by the UW-L campus community.

Donations from the UW-L campus community are delivered at Gundersen.

Donations from the UW-L campus community are delivered at Gundersen.

The gifts including snacks, games, gift cards, thank-you notes and more were donated by the UW-L campus community.

Donations from the UW-L campus community.

Nurses and a representative from the Gundersen Medical Foundation met the UW-L students and faculty.

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Delayed cord blood clamping: a health boost for babies, and potentially for others - La Crosse Tribune

Cell Tissue Res. Author manuscript; available in PMC 2018 May 22.

Published in final edited form as:

PMCID: PMC5963504

NIHMSID: NIHMS967727

1Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA

2Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA

1Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA

1Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA

2Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA

The astonishing progress in the field of stem cell biology during the past 40 years has transformed both science and medicine. Neural stem cells (NSCs) are the stem cells of the nervous system. During development they give rise to the entire nervous system. In adults, a small number of NSCs remain and are mostly quiescent; however, ample evidence supports their important roles in plasticity, aging, disease, and regeneration of the nervous system. Because NSCs are regulated by both intrinsic genetic and epigenetic programs and extrinsic stimuli transduced through the stem cell niche, dysregulation of NSCs due to either genetic causes or environmental impacts may lead to disease. Therefore, extensive investigations in the past decades have been devoted to understanding how NSCs are regulated. On the other hand, ever since their discovery, NSCs have been a focal point for cell-based therapeutic strategies in the brain and spinal cord. The limited number of NSCs residing in the tissue has been a limiting factor for their clinical applications. Although recent advancements in embryonic and induced pluripotent stem cells have provided novel sources for NSCs, several challenges remain. In this special issue, leaders and experts in NSCs summarize our current understanding of NSC molecular regulation and the importance of NSCs for disease modeling and translational applications.

The term stem cells first appeared in the scientific literature in 1868 by the German biologist Ernst Haeckel (Haeckel, 1868). In his writings (Haeckel, 1868), stem cells had two distinct meanings: one is the unicellular evolutionary origin of all multicellular organisms, and the other is the fertilized egg giving rise to all other cell types of the body. The latter definition has evolved into the modern definition of stem cells - cells that can divide to self-renew and to differentiate into other cell types in tissues and organs (Li and Zhao, 2008, Ramalho-Santos and Willenbring, 2007).

The behavior and fate of stem cells are strongly influenced by their specific anatomical locations and surrounding cell types, called the stem cell niche. The niche provides physical support to host or anchor stem cells, and supplies factors to maintain and regulate them (Li and Zhao, 2008). Stem cells are also regulated by intrinsic signaling cascades and transcriptional mechanisms, some of which are common among all stem cells, and others that are unique to specific types. Some of the best known regulators include TGF-, BMP, Smad, Wnt, Notch, EGF fibroblast growth factors (Jobe, et al., 2012, Li and Zhao, 2008). Therefore, stem cells are regulated by complex mechanisms in both temporal- and context-specific manners to maintain their unique characteristics. Understanding stem cell regulation gives us the opportunity to explore mechanisms of development, as well as disorders resulting from their dysfunction.

During development, the central nervous system (CNS) is generated from a small number of neural stem cells (NSCs) lining the neural tube (Kriegstein and Alvarez-Buylla, 2009). A great deal of experimental evidence has demonstrated that radial glia, the NSCs during mammalian CNS development, undergo both symmetric divisions to expand the NSC pool, and asymmetric divisions to give rise to intermediate progenitors (IPCs) and the differentiated cell types. The three major cell types in the CNS arise from NSCs in a temporally defined sequence, with neurons appearing first, followed by astrocytes, and then oligodendrocytes (Okano and Temple, 2009). The technical advancement of live imaging and genomic tools have allowed for the identification of human-specific NSC populations (e.g. outer radial glia, or oRG) located at the outer subventricular zone (SVZ) (Gertz, et al., 2014). These oRG are essential for cortical expansion to achieve the large size of the human cortex. Single-cell genomic technologies have identified specific oRG markers that might be used for further characterization of these cells (Liu, et al., 2016, Pollen, et al., 2014). Investigating the regulatory mechanisms governing the self-renewal and fate specification of NSCs, especially human-specific developmental features, has significantly contributed to our understanding of human brain development and developmental diseases. In addition, this knowledge also has helped scientists refine protocols for pluripotent stem cell differentiation into specific nervous system cell types for both therapeutic goals and disease modeling.

In adult brains, NSCs are reduced and become restricted to specific brain regions. In rodents, both NSCs and ongoing neurogenesis have been widely documented in the SVZ of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus (DG) of the hippocampus (Kempermann, et al., 2015). In humans, experimental evidence has supported ongoing neurogenesis in the hippocampus (Eriksson, et al., 1998, Spalding, et al., 2013). The confirmation of mammalian adult neurogenesis in the 1990s was one of the most exciting moments in science in the 21st century. Not only did it overthrow the prevailing dogma suggesting no neurons were made in the adult brain, but also it hinted that these adult NSCs could be utilized for neural repair in disease and following injury. Forty years later, we have learned a lot about NSCs. In the adult rodent SVZ, neurogenesis has been shown to be important for olfactory function and olfactory learning (Alonso, et al., 2006). During development, a subset of slowly-dividing NSCs are set aside to be the NSCs of the SVZ in the postnatal and adult brain (Fuentealba, et al., 2015, Furutachi, et al., 2015). The majority of neurogenic radial glia, however, become astrocytes and ependymal cells at the end of embryonic neurogenesis (Noctor, et al., 2004). A subset of these astrocytes persist as NSCs in specialized niches in the adult brain and continuously generate neurons that functionally integrate into restricted brain regions (Doetsch, 2003). In the hippocampus, radial glia-like stem cells of the SGZ make newborn neurons throughout life (Goritz and Frisen, 2012). These newborn neurons integrate into the circuity of the DG, contributing to behaviors such as pattern separation (Aimone, et al., 2011) and spatial learning (Dupret, et al., 2008), as well as hippocampus-associated learning, memory, and executive functions (Kempermann, Song and Gage, 2015).

Significant effort has been devoted into understanding the regulation of adult neurogenesis. As a result, we now know that many extrinsic stimuli and intrinsic mechanisms can affect this process. Mouse genetic studies have clearly demonstrated the important role of transcriptional regulation of NSCs through intrinsic genetic mechanisms (Hsieh and Zhao, 2016). Some examples include SOXC family proteins [Kavyanifar et al, in this issue (Kavyanifar, et al., 2018)], Bmi-1 (Molofsky, et al., 2003), Sox2 (Ferri, et al., 2004, Graham, et al., 1999), PTEN (Bonaguidi, et al., 2011), and Notch [Zhang et al, in this issue (Zhang, et al., 2018)]. In addition epigenetic regulation by DNA methylation pathways (e.g. Mbd1, Mecp2, Dnmt, Tet) (Noguchi, et al., 2015, Smrt, et al., 2007, Tsujimura, et al., 2009, Zhang, et al., 2013, Zhao, et al., 2003), chromatin remodeling (e.g. BAF, BRG1) (Ninkovic, et al., 2013, Petrik, et al., 2015, Tuoc, et al., 2017), and noncoding RNAs (Liu, et al., 2010)[Anderson and Lim, in this issue (Anderson and Lim, 2018)] play important roles. Many growth factors, signaling molecules, and neurotransmitters have been shown to regulate neurogenesis (Kempermann, Song and Gage, 2015). Catavero et al [in this issue (Catavero, et al., 2018)] review the role of GABA circuits, signaling, and receptors in regulating development of adult born cells, as well as the molecular players that modulate GABA signaling. Because progenitors with multipotent differentiation potentials have been found in brain regions without active neurogenesis (Palmer, et al., 1997), it is hypothesized that these progenitors might be manipulated to become neuron-competent in vivo so that they can contribute to brain generation [Wang et al, in this issue (Wang and Zhang, 2018)].

A great amount of literature has documented how physiological activities and enriched environment influences adult neurogenesis (Kempermann, Song and Gage, 2015). However, as summarized by Eisinger and Zhao [in this issue (Eisinger and Zhao, 2018)], the genes and gene network involved in these changes within NSCs have not been systematically analyzed at genome wide levels. Adult neurogenesis is also influenced by diseases including epilepsy (Parent and Lowenstein, 1997), stroke (Zhang and Chopp, 2016), depression (Dranovsky and Hen, 2006, Kempermann, et al., 2003), and injury [(Morshead and Ruddy, in this issue (Morshead and Ruddy, 2018) in this issue). Thodeson et al [in this issue (Thodeson, et al., 2018)] further summarize the contribution and dysregulation of adult neurogenesis in epilepsy and discuss how we can translate these findings to human therapeutics by using patient-derived neurons to study monogenic epilepsy-in-a-dish.

Aging affects every individual and is a major risk factor for many diseases. One of the strongest negative regulators of adult neurogenesis is aging. Both intrinsic and extrinsic components regulate the limitations of NSC proliferation and function (Moore and Jessberger, 2017, Seib and Martin-Villalba, 2015). In this issue, Mosher and Schaffer (Mosher and Schafer, 2018) and Ruddy and Morshead (Morshead and Ruddy, 2018) examine factors such as secreted signals, cell contact- dependent signals, and extracellular matrix cues that control neurogenesis in an age-dependent manner, and define these signals by the extrinsic mechanism through which they are presented to the NSCs. Smith et al [in this issue (Smith, et al., 2018)] discuss how age-related changes in the blood, such as blood-borne-factors, and peripheral immune cells, contribute to the age-related decline in adult neurogenesis in the mammalian brain.

Despite the extensive knowledge we have gained regarding adult neurogenesis, critical questions remain. For example, the control of the functional integration of new neurons remains a mystery. It has been shown that adult NSC-differentiated newborn neurons exhibit a critical period for sensitivity to external stimuli (Bergami, et al., 2015), and a heightened sensitivity to seizures (Kron, et al., 2010). It remains unclear how new neurons choose their connections. Jahn and Bergami [in this issue (Jahn and Bergami, 2018)] further discuss the critical period and its regulators during adult newborn neuron development.

Understanding the extrinsic and intrinsic regulation of adult NSCs and their newborn progeny, and their response to both positive and negative stimuli will further illuminate their role in disease, injury, stress, and brain function.

Human pluripotent stem cells (PSCs), including human embryonic stem cells (ESCs) and induced PSCs (iPSCs), offer a model system to reveal cellular and molecular events underlying normal and abnormal neural development in humans. ESCs are pluripotent cells derived from the inner cell mass of blastocyst stage preimplantation embryos, which were first isolated from mouse by Evans and Kaufman in 1981 (Evans and Kaufman, 1981) and later from humans by James Thompson in 1998 (Thomson, et al., 1998). Human ESCs are invaluable in the study of early embryonic development, allowing us to identify critical regulators of cell commitment, differentiation, and adult cell reprogramming (Dvash, et al., 2006, Ren, et al., 2009). iPSCs are reprogrammed from somatic cells by forced expression of stem cell genes and have the characteristics of ESCs (Okita, et al., 2007, Yu, et al., 2007). The development of iPSC technology has allowed us access to cells of the human nervous system through reprogramming of patient-derived cells, revolutionizing our ability to study human development and diseases.

To generate neural cells from either ESCs or iPSCs, the first step is neural induction. Through actions of a number of activators and inhibitors of cell signaling pathways, this process yields neural epithelial cell-like NSCs and then intermediate neural progenitors, resembling embryonic development. Despite many advances, a major hurdle of neural differentiation is lineage control. Using a standard dorsal forebrain neural differentiation protocol, most neural progenitors obtained are forebrain excitatory progenitors that produce mostly forebrain glutamatergic excitatory neurons. However, the purity and layer-specific composition of these progenitors, as well as neurons, vary significantly from experiment to experiment, cell line to cell line, and lab to lab. In addition, differentiation into specific types of neurons with high purity has always been a challenging goal. Much effort has been devoted into improving the efficiency of dopaminergic neuron and GABAergic neuron differentiation with great success (Hu, et al., 2010). However, the brain has many other types of neurons. Vadodaria et al [in this issue (Vadodaria, et al., 2018)] discuss how to generate serotonergic neurons, a type of neuron highly relevant to psychiatric disorders. To better understand the molecular control of human PSC and NSC differentiation, where protocols result in a large amount of cellular heterogeneity in identity and response, analysis must be done at the level of single cells. Harbom et al [in this issue (Harbom, et al., 2018)] summarizes how new state-of-the-art single-cell analysis methods may help to define differentiation from pluripotent cells.

The advancement in iPSC and gene editing technology has transformed the field of human disease modeling. As in many human disorders, especially neuropsychiatric disorders, mouse models have been useful. Yet there are several critical reasons why it is necessary to use human cells to define the underlying mechanisms that lead to human patient characteristics, particularly those affecting the nervous system. For example, in fragile X syndrome (FXS), the epigenetic silencing of the Fragile X Mental Retardation Gene 1 (FMR1) gene that causes FXS occurs only in humans. Mice engineered to mimic the human mutation in the FMR1 gene do not show the same methylation and silencing characteristics of the gene as in humans (Brouwer, et al., 2007). These results indicate that some epigenetic mechanisms in human and mice are different and preclude the ability to study epigenetic mechanisms of FMR1 silencing in mouse models of FXS (Bhattacharyya and Zhao, 2016). In this issue, Li and Shi discuss disease modeling using human PSC-differentiated neural progenitors (Li, et al., 2018), and Brito et al specifically focus on modeling autism spectrum disorder (Brito, et al., 2018).

The use of NSCs as a treatment strategy in CNS disease and injury has been tested for decades. Parkinsons disease specifically has gained the most momentum for potential therapeutic benefits (Studer, 2017); however, similar work has been performed in Huntingtons disease, stroke, and following spinal cord injury [for a review on this topic, see (Vishwakarma, et al., 2014)]. In some of these paradigms, NSCs are expected to differentiate into a specific cell type in the local CNS environment; in other cases, they are in a supportive role. In this issue, Kameda et al explores progress in using NSCs as a therapy following spinal cord injury (Kameda, et al., 2018).

While the development of PSC technologies has been a scientific breakthrough for future studies, there are limitations and risks that may be associated with their use. ESCs, iPSCs, and their differentiated NSCs are dividing cells. Either transplantation of NSCs or in vivo reprogramming of endogenous cells into NSCs could lead to tumorigenesis. In addition, reprogramming somatic cells into iPSCs results in a loss of some epigenetic signatures of disease and aging which are critical for disease modeling (Mertens, et al., 2015, Miller, et al., 2013, Ocampo, et al., 2016). In recent years, direct reprogramming of fibroblasts or other cell types into induced neurons (iN) has been developed (for review see (Mertens, et al., 2016)). Remarkably a growing number of studies have demonstrated that such direct reprogramming also can be effective in vivo. Wang et al [(Wang and Zhang, 2018) in this issue] will summarize recent progress of in vivo reprogramming into new neurons and present how this method can be used for spinal cord injury.

In cellular reprogramming, the cells targeted and the genetic factors used vary; however, the biggest difference is that some protocols push cells through a NSC stage, whereas others skip these stages (Gascon, et al., 2017, Guo, et al., 2014, Wang, et al., 2016). Bypassing this developmental stage has both pros and cons, and may lead to a completely novel path towards lineage commitment [discussed by Falk and Karow (Falk and Karow, 2018) in this issue].

NSCs are fascinating and promising cells because of their capability, flexibility, and multiplicity. Understanding how NSCs function provides important knowledge in development, adaptation, disease, regeneration, and rehabilitation of the nervous system. The studies of cortical development and adult neurogenesis using rodent models have contributed significantly to our knowledge about NSCs and will continually yield important new information, taking advantage of novel genetic and imaging technologies. However, using human NSCs provides us with a window to investigate human-specific aspects of development and disease mechanisms, which is potentiated by the fast advancement of stem cell and gene editing technologies. Challenges still remain regarding cell lineage control, in vivo NSC behavior, three dimensional cellular interactions, and preservation of epigenetic and aging marks.

We thank Klaus Unsicker for his encouragement and support and Jutta Jger for her help with invitations, and communications with authors and reviewers. This work was supported by grants from the US National Institutes of Health (R01MH078972, R56MH113146, R21NS098767, and R21NS095632 to X.Z, U54HD090256 to the Waisman Center), University of Wisconsin (UW)-Madison Vilas Trust (Kellett Mid-Career Award to X.Z.) and UW-Madison and Wisconsin Alumni Research Foundation (WARF to X.Z.), Jenni and Kyle Professorship (to X.Zhao), a Sloan Research Fellowship (to D.L.M.), a Junior Faculty Grant from the American Federation for Aging Research (to D.L.M.), and startup funds from UW-Madison School of Medicine and Public Health, WARF, and the Neuroscience Department (to D.L.M.).

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Neural stem cells: developmental mechanisms and disease modeling

Stem cell technology will transform medical practice. While stem cell research has already elucidated many basic disease mechanisms, the promise of stem cellbased therapies remains largely unrealized. In this review, we begin with an overview of different stem cell types. Next, we review the progress in using stem cells for regenerative therapy. Last, we discuss the risks associated with stem cellbased therapies.

There are three major types of stem cells as follows: adult stem cells (also called tissue-specific stem cells), embryonic stem (ES) cells, and induced pluripotent stem (iPS) cells.

A majority of adult stem cells are lineage-restricted cells that often reside within niches of their tissue of origin. Adult stem cells are characterized by their capacity for self-renewal and differentiation into tissue-specific cell types. Many adult tissues contain stem cells including skin, muscle, intestine, and bone marrow (Gan et al, 1997; Artlett et al, 1998; Matsuoka et al, 2001; Coulombel, 2004; Humphries et al, 2011). However, it remains unclear whether all adult organs contain stem cells. Adult stem cells are quiescent but can be induced to replicate and differentiate after tissue injury to replace cells that have died. The process by which this occurs is poorly understood. Importantly, adult stem cells are exquisitely tissue-specific in that they can only differentiate into the mature cell type of the organ within which they reside (Rinkevich et al, 2011).

Thus far, there are few accepted adult stem cellbased therapies. Hematopoietic stem cells (HSCs) can be used after myeloablation to repopulate the bone marrow in patients with hematologic disorders, potentially curing the underlying disorder (Meletis and Terpos, 2009; Terwey et al, 2009; Casper et al, 2010; Hill and Copelan, 2010; Hoff and Bruch-Gerharz, 2010; de Witte et al, 2010). HSCs are found most abundantly in the bone marrow, but can also be harvested at birth from umbilical cord blood (Broxmeyer et al, 1989). Similar to the HSCs harvested from bone marrow, cord blood stem cells are tissue-specific and can only be used to reconstitute the hematopoietic system (Forraz et al, 2002; McGuckin et al, 2003; McGuckin and Forraz, 2008). In addition to HSCs, limbal stem cells have been used for corneal replacement (Rama et al, 2010).

Mesenchymal stem cells (MSCs) are a subset of adult stem cells that may be particularly useful for stem cellbased therapies for three reasons. First, MSCs have been isolated from a variety of mesenchymal tissues, including bone marrow, muscle, circulating blood, blood vessels, and fat, thus making them abundant and readily available (Deans and Moseley, 2000; Zhang et al, 2009; Lue et al, 2010; Portmann-Lanz et al, 2010). Second, MSCs can differentiate into a wide array of cell types, including osteoblasts, chondrocytes, and adipocytes (Pittenger et al, 1999). This suggests that MSCs may have broader therapeutic applications compared to other adult stem cells. Third, MSCs exert potent paracrine effects enhancing the ability of injured tissue to repair itself. In fact, animal studies suggest that this may be the predominant mechanism by which MSCs promote tissue repair. The paracrine effects of MSC-based therapy have been shown to aid in angiogenic, antiapoptotic, and immunomodulatory processes. For instance, MSCs in culture secrete hepatocyte growth factor (HGF), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF) (Nagaya et al, 2005). In a rat model of myocardial ischemia, injection of human bone marrow-derived stem cells upregulated cardiac expression of VEGF, HGF, bFGF, angiopoietin-1 and angiopoietin-2, and PDGF (Yoon et al, 2005). In swine, injection of bone marrow-derived mononuclear cells into ischemic myocardium was shown to increase the expression of VEGF, enhance angiogenesis, and improve cardiac performance (Tse et al, 2007). Bone marrow-derived stem cells have also been used in a number of small clinical trials with conflicting results. In the largest of these trials (REPAIR-AMI), 204 patients with acute myocardial infarction were randomized to receive bone marrow-derived progenitor cells vs placebo 37 days after reperfusion. After 4 months, the patients that were infused with stem cells showed improvement in left ventricular function compared to control patients. At 1 year, the combined endpoint of recurrent ischemia, revascularization, or death was decreased in the group treated with stem cells (Schachinger et al, 2006).

Embryonic stem cells are derived from the inner cell mass of the developing embryo during the blastocyst stage (Thomson et al, 1998). In contrast to adult stem cells, ES cells are pluripotent and can theoretically give rise to any cell type if exposed to the proper stimuli. Thus, ES cells possess a greater therapeutic potential than adult stem cells. However, four major obstacles exist to implementing ES cells therapeutically. First, directing ES cells to differentiate into a particular cell type has proven to be challenging. Second, ES cells can potentially transform into cancerous tissue. Third, after transplantation, immunological mismatch can occur resulting in host rejection. Fourth, harvesting cells from a potentially viable embryo raises ethical concerns. At the time of this publication, there are only two ongoing clinical trials utilizing human ES-derived cells. One trial is a safety study for the use of human ES-derived oligodendrocyte precursors in patients with paraplegia (Genron based in Menlo Park, California). The other is using human ES-derived retinal pigmented epithelial cells to treat blindness resulting from macular degeneration (Advanced Cell Technology, Santa Monica, CA, USA).

In stem cell research, the most exciting recent advancement has been the development of iPS cell technology. In 2006, the laboratory of Shinya Yamanaka at the Gladstone Institute was the first to reprogram adult mouse fibroblasts into an embryonic-like cell, or iPS cell, by overexpression of four transcription factors, Oct3/4, Sox2, c-Myc, and Klf4 under ES cell culture conditions (Takahashi and Yamanaka, 2006). Yamakana's pioneering work in cellular reprogramming using adult mouse cells set the foundation for the successful creation of iPS cells from adult human cells by both his team (Takahashi et al, 2007) and a group led by James Thomson at the University of Wisconsin (Yu et al, 2007). These initial proof of concept studies were expanded upon by leading scientists such as George Daley, who created the first library of disease-specific iPS cell lines (Park et al, 2008). These seminal discoveries in the cellular reprogramming of adult cells invigorated the stem cell field and created a niche for a new avenue of stem cell research based on iPS cells and their derivatives. Since the first publication on cellular reprogramming in 2006, there has been an exponential growth in the number of publications on iPS cells.

Similar to ES cells, iPS cells are pluripotent and, thus, have tremendous therapeutic potential. As of yet, there are no clinical trials using iPS cells. However, iPS cells are already powerful tools for modeling disease processes. Prior to iPS cell technology, in vitro cell culture disease models were limited to those cell types that could be harvested from the patient without harm usually dermal fibroblasts from skin biopsies. However, mature dermal fibroblasts alone cannot recapitulate complicated disease processes involving multiple cell types. Using iPS technology, dermal fibroblasts can be de-differentiated into iPS cells. Subsequently, the iPS cells can be directed to differentiate into the cell type most beneficial for modeling a particular disease process. Advances in the production of iPS cells have found that the earliest pluripotent stage of the derivation process can be eliminated under certain circumstances. For instance, dermal fibroblasts have been directly differentiated into dopaminergic neurons by viral co-transduction of forebrain transcriptional regulators (Brn2, Myt1l, Zic1, Olig2, and Ascl1) in the presence of media containing neuronal survival factors [brain-derived neurotrophic factor, neurotrophin-3 (NT3), and glial-conditioned media] (Qiang et al, 2011). Additionally, dermal fibroblasts have been directly differentiated into cardiomyocyte-like cells using the transcription factors Gata4, Mef2c, and Tb5 (Ieda et al, 2010). Regardless of the derivation process, once the cell type of interest is generated, the phenotype central to the disease process can be readily studied. In addition, compounds can be screened for therapeutic benefit and environmental toxins can be screened as potential contributors to the disease. Thus far, iPS cells have generated valuable in vitro models for many neurodegenerative (including Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis), hematologic (including Fanconi's anemia and dyskeratosis congenital), and cardiac disorders (most notably the long QT syndrome) (Park et al, 2008). iPS cells from patients with the long QT syndrome are particularly interesting as they may provide an excellent platform for rapidly screening drugs for a common, lethal side effect (Zwi et al, 2009; Malan et al, 2011; Tiscornia et al, 2011). The development of patient-specific iPS cells for in vitro disease modeling will determine the potential for these cells to differentiate into desired cell lineages, serve as models for investigating the mechanisms underlying disease pathophysiology, and serve as tools for future preclinical drug screening and toxicology studies.

Despite substantial improvements in therapy, cardiovascular disease remains the leading cause of death in the industrialized world. Therefore, there is a particular interest in cardiovascular regenerative therapies. The potential of diverse progenitor cells to repair damaged heart tissue includes replacement (tissue transplant), restoration (activation of resident cardiac progenitor cells, paracrine effects), and regeneration (stem cell engraftment forming new myocytes) (Codina et al, 2010). It is unclear whether the heart contains resident stem cells. However, experiments show that bone marrow mononuclear cells (BMCs) can repair myocardial damage, reduce left ventricular remodeling, and improve heart function by myocardial regeneration (Hakuno et al, 2002; Amado et al, 2005; Dai et al, 2005; Schneider et al, 2008). The regenerative capacity of human heart tissue was further supported by the detection of the renewal of human cardiomyocytes (1% annually at the age of 25) by analysis of carbon-14 integration into human cardiomyocyte DNA (Bergmann et al, 2009). It is not clear whether cardiomyocyte renewal is derived from resident adult stem cells, cardiomyocyte duplication, or homing of non-myocardial progenitor cells. Bone marrow cells home to the injured myocardium as shown by Y chromosome-positive BMCs in female recipients (Deb et al, 2003). On the basis of these promising results, clinical trials in patients with ischemic heart disease have been initiated primarily using bone marrow-derived cells. However, these small trials have shown controversial results. This is likely due to a lack of standardization for cell harvesting and delivery procedures. This highlights the need for a better understanding of the basic mechanisms underlying stem cell isolation and homing prior to clinical implementation.

Although stem cells have the capacity to differentiate into neurons, oligodendrocytes, and astrocytes, novel clinical stem cellbased therapies for central and peripheral nervous system diseases have yet to be realized. It is widely hoped that transplantation of stem cells will provide effective therapy for Parkinson's disease, Alzheimer's disease, Huntington's Disease, amyloid lateral sclerosis, spinal cord injury, and stroke. Several encouraging animal studies have shown that stem cells can rescue some degree of neurological function after injury (Daniela et al, 2007; Hu et al, 2010; Shimada and Spees, 2011). Currently, a number of clinical trials have been performed and are ongoing.

Dental stem cells could potentially repair damaged tooth tissues such as dentin, periodontal ligament, and dental pulp (Gronthos et al, 2002; Ohazama et al, 2004; Jo et al, 2007; Ikeda et al, 2009; Balic et al, 2010; Volponi et al, 2010). Moreover, as the behavior of dental stem cells is similar to MSCs, dental stem cells could also be used to facilitate the repair of non-dental tissues such as bone and nerves (Huang et al, 2009; Takahashi et al, 2010). Several populations of cells with stem cell properties have been isolated from different parts of the tooth. These include cells from the pulp of both exfoliated (children's) and adult teeth, the periodontal ligament that links the tooth root with the bone, the tips of developing roots, and the tissue that surrounds the unerupted tooth (dental follicle) (Bluteau et al, 2008). These cells probably share a common lineage from neural crest cells, and all have generic mesenchymal stem cell-like properties, including expression of marker genes and differentiation into mesenchymal cells in vitro and in vivo (Bluteau et al, 2008). different cell populations do, however, differ in certain aspects of their growth rate in culture, marker gene expression, and cell differentiation. However, the extent to which these differences can be attributed to tissue of origin, function, or culture conditions remains unclear.

There are several issues determining the long-term outcome of stem cellbased therapies, including improvements in the survival, engraftment, proliferation, and regeneration of transplanted cells. The genomic and epigenetic integrity of cell lines that have been manipulated in vitro prior to transplantation play a pivotal role in the survival and clinical benefit of stem cell therapy. Although stem cells possess extensive replicative capacity, immune rejection of donor cells by the host immune system post-transplantation is a primary concern (Negro et al, 2012). Recent studies have shown that the majority of donor cell death occurs in the first hours to days after transplantation, which limits the efficacy and therapeutic potential of stem cellbased therapies (Robey et al, 2008).

Although mouse and human ES cells have traditionally been classified as being immune privileged, a recent study used in vivo, whole-animal, live cell-tracing techniques to demonstrate that human ES cells are rapidly rejected following transplantation into immunocompetent mice (Swijnenburg et al, 2008). Treatment of ES cell-derived vascular progenitor cells with inter-feron (to upregulate major histocompatibility complex (MHC) class I expression) or in vivo ablation of natural killer (NK) cells led to enhanced progenitor cell survival after transplantation into a syngeneic murine ischemic hindlimb model. This suggests that MHC class I-dependent, NK cell-mediated elimination is a major determinant of graft survivability (Ma et al, 2010). Given the risk of rejection, it is likely that initial therapeutic attempts using either ES or iPS cells will require adjunctive immunosuppressive therapy. Immunosuppressive therapy, however, puts the patient at risk of infection as well as drug-specific adverse reactions. As such, determining the mechanisms regulating donor graft tolerance by the host will be crucial for advancing the clinical application of stem cellbased therapies.

An alternative strategy to avoid immune rejection could employ so-called gene editing. Using this technique, the stem cell genome is manipulated ex vivo to correct the underlying genetic defect prior to transplantation. Additionally, stem cell immunologic markers could be manipulated to evade the host immune response. Two recent papers offer alternative methods for gene editing. Soldner et al (2011) used zinc finger nuclease to correct the genetic defect in iPS cells from patients with Parkinson's disease because of a mutation in the -Synuclein (-SYN) gene. Liu et al (2011) used helper-dependent adenoviral vectors (HDAdV) to correct the mutation in the Lamin A (LMNA) gene in iPS cells derived from patients with HutchinsonGilford Progeria (HGP), a syndrome of premature aging. Cells from patients with HGP have dysmorphic nuclei and increased levels of progerin protein. The cellular phenotype is especially pronounced in mature, differentiated cells. Using highly efficient helper-dependent adenoviral vectors containing wild-type sequences, they were able to use homologous recombination to correct two different Lamin A mutations. After genetic correction, the diseased cellular phenotype was reversed even after differentiation into mature smooth muscle cells. In addition to the potential therapeutic benefit, gene editing could generate appropriate controls for in vitro studies.

Finally, there are multiple safety and toxicity concerns regarding the transplantation, engraftment, and long-term survival of stem cells. Donor stem cells that manage to escape immune rejection may later become oncogenic because of their unlimited capacity to replicate (Amariglio et al, 2009). Thus, ES and iPS cells may need to be directed into a more mature cell type prior to transplantation to minimize this risk. Additionally, generation of ES and iPS cells harboring an inducible kill-switch may prevent uncontrolled growth of these cells and/or their derivatives. In two ongoing human trials with ES cells, both companies have provided evidence from animal studies that these cells will not form teratomas. However, this issue has not been thoroughly examined, and enrolled patients will need to be monitored closely for this potentially lethal side effect.

In addition to the previously mentioned technical issues, the use of ES cells raises social and ethical concerns. In the past, these concerns have limited federal funding and thwarted the progress of this very important research. Because funding limitations may be reinstituted in the future, ES cell technology is being less aggressively pursued and young researchers are shying away from the field.

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The benefits and risks of stem cell technology - PMC