In a groundbreaking study that provides scientists with a critical new understanding of stem cell development and its role in disease, UCLA researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research led by Dr. Kathrin Plath, professor of biological chemistry, have established a first-of-its-kind methodology that defines the unique stages by which specialized cells are reprogrammed into stem cells that resemble those found in the embryo.

The study was published online ahead of print in the journal Cell.

Induced pluripotent stem cells (known as iPSCs) are similar to human embryonic stem cells in that both cell types have the unique ability to self-renew and have the flexibility to become any cell in the human body. iPSC cells, however, are generated by reprogramming skin or blood cells and do not require an embryo.

Reprogramming is a long process (about one to two weeks) and largely inefficient, with typically less than one percent of the primary skin or blood cells successfully completing the journey to becoming an iPSC. The exact stages a cell goes through during the reprogramming process are also not well understood. This knowledge is important, as iPSCs hold great promise in the field of regenerative medicine, as they can provide a single source of patient-specific cells to replace those lost to injury or disease. They can also be used to create novel disease models from which new drugs and therapies can be developed.

"This research has broad impact, because by deepening our understanding of cell reprogramming we have the potential to improve disease modeling and the generation of better sources of patient-specific specialized cells suitable for replacement therapy," said Plath. "This can ultimately benefit patients with new and better treatments for a wide range of diseases.

Drs. Vincent Pasque and Jason Tchieu, postdoctoral fellows in the lab of Dr. Plath and co-first authors of the study, developed a roadmap of the reprogramming process using detailed time-course analyses. They induced the reprogramming of skin cells into iPSC, then observed and analyzed on a daily basis or every other day the process of transformation at the single-cell level. The data were collected and recorded over a period of up to two weeks.

Plath's team found that the changes that happen in cells during reprogramming occur in a sequential stage-by-stage manner, and that importantly, the stages were the same across all the different reprogramming systems and different cell types analyzed.

"The exact stage of reprogramming of any cell can now be determined," said Pasque. "This study signals a big change in thinking, because it provides simple and efficient tools for scientists to study stem cell creation in a stage-by-stage manner. Most studies to date ignore the stages of reprogramming, but we can now seek to better understand the entire process on both a macro and micro level."

Plath's team further discovered that the stages of reprogramming to iPSC are different from what was expected. They found that it is not simply the reversed sequence of stages of embryo development. Some steps are reversed in the expected order; others do not actually happen in the exact reverse order and resist a change until late during reprogramming to iPSCs.

"This reflects how cells do not like to change from one specialized cell type to another and resist a change in cell identity," said Pasque. "Resistance to reprogramming also helps to explain why reprogramming takes place only in a very small proportion of the starting cells."

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Pioneering method developed to define stages of stem cell reprogramming

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Newswise A powerful genome editing technology known as CRISPR has been used by researchers since 2012 to trim, disrupt, replace or add to sequences of an organisms DNA. Now, scientists at Johns Hopkins Medicine have shown that the system also precisely and efficiently alters human stem cells.

In a recent online report on the work in Molecular Therapy, the Johns Hopkins team says the findings could streamline and speed efforts to modify and tailor human-induced pluripotent stem cells (iPSCs) for use as treatments or in the development of model systems to study diseases and test drugs.

Stem cell technology is quickly advancing, and we think that the days when we can use iPSCs for human therapy arent that far away, says Zhaohui Ye, Ph.D., an instructor of medicine at the Johns Hopkins University School of Medicine. This is one of the first studies to detail the use of CRISPR in human iPSCs, showcasing its potential in these cells.

CRISPR originated from a microbial immune system that contains DNA segments known as clustered regularly interspaced short palindromic repeats. The engineered editing system makes use of an enzyme that nicks together DNA with a piece of small RNA that guides the tool to where researchers want to introduce cuts or other changes in the genome.

Previous research has shown that CRISPR can generate genomic changes or mutations through these interventions far more efficiently than other gene editing techniques, such as TALEN, short for transcription activator-like effector nuclease.

Despite CRISPRs advantages, a recent study suggested that it might also produce a large number of off-target effects in human cancer cell lines, specifically modification of genes that researchers didnt mean to change.

To see if this unwanted effect occurred in other human cell types, Ye; Linzhao Cheng, Ph.D., a professor of medicine and oncology in the Johns Hopkins University School of Medicine; and their colleagues pitted CRISPR against TALEN in human iPSCs, adult cells reprogrammed to act like embryonic stem cells. Human iPSCs have already shown enormous promise for treating and studying disease.

The researchers compared the ability of both genome editing systems to either cut out pieces of known genes in iPSCs or cut out a piece of these genes and replace it with another. As model genes, the researchers used JAK2, a gene that when mutated causes a bone marrow disorder known as polycythemia vera; SERPINA1, a gene that when mutated causes alpha1-antitrypsin deficiency, an inherited disorder that may cause lung and liver disease; and AAVS1, a gene thats been recently discovered to be a safe harbor in the human genome for inserting foreign genes.

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'CRISPR' Science: Newer Genome Editing Tool Shows Promise in Engineering Human Stem Cells

By: Adam Feuerstein | 01/05/15 - 10:52 AM EST

Once injected, the NurOwn stem cells bathe the damaged neurons of ALS patients with secretions of nerve growth factors. Brainstorm has a home run on its hands if NurOwn can be shown to slow or halt the progressive destruction of neurons, and if that disease-modifying effect translates into improved muscle function for ALS patients. Monday's update comes from a Phase IIa trial in which 14 ALS patientswere followed for the three months without treatment. At month four, each patient wastransplanted with their own personalized NurOwn therapy and then assessed every month for six months. Brainstorm evaluated NurOwn's impact on ALS disease progression using the ALSFRS score, a commonly used assessment of treatment response and muscle function in ALS patients. Lung function, another commonly used measure of efficacy in ALS clinical trials, was also measured.

Twelve ALS patients were evaluable for response. Of these, 11 patientsshowed aslowing of ALS disease progression at six months compared to baseline, measured either by improved ALSFRS or lung function scores, Brainstorm said. Two other patients enrolled in the study died. Administration of the NurOwn therapy was well tolerated by patients, the company said.

The final Phase IIa data announced Monday were a small improvement over interim results from the same study presented last June. Further, detailed data from the study will be presented at a medical meeting later this year. For perspective purposes, it's important to note that this phase IIa study enrolled a relatively small number of ALS patients and was conducted at a single hospital in Israel. This doesn't necessarily discredit the positive results, but conclusions about NurOwn's ultimate benefit as an ALS therapy can't be drawnuntil data from larger studies are gathered.

Brainstorm is conducting another, larger Phase II study in the U.S., enrolling 48 ALS patients who will be randomized 3:1 to receive a single NurOwn treatment in the muscle and spine, or a placebo treatment. The study is being conducted at two hospitals in Massachusetts, UMass Medical Center and Massachusetts General, and the Minnesota-based Mayo Clinic. The study's primary endpoint is the safety and tolerability of NurOwn, but investigators will also assess ALS patients for efficacy using measures of ALS disease activity and muscle function. The first patient was enrolled into the Phase II study last June and Brainstorm expects results to be ready in the first half of 2016.

The company is also in the planning stages for another Phase II study in which ALS patients will be treated with multiple doses of NurOwn. Must Read: 11 Best Small-Cap Technology Stocks That Could Hit It Big in 2015

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Brainstorm Stem-Cell Therapy Continues to Show Treatment Effect in ALS Patients