SOCIETY FOR NEUROSCIENCE NEWS: Mouse embryonic stem cells differentiate in opossum eyes – BioProcess Online

Findings have implications for treating eye diseases as well as brain disorders

In a positive sign for future treatment of human eye diseases, researchers from Iowa State University (Ames) and Harvard Medical School (Boston) found that transplanted mouse stem cells become integrated into the retinas of Brazilian opossums.

"The research is a promising step for using cell replacements to treat diseases of the human eye like glaucoma, macular degeneration, and diabetic retinopathy," said Don Sakaguchi, a developmental neurobiologist and associate professor of zoology and genetics at Iowa State.

"The work also may have implications for treating brain disorders such as Parkinson's and Alzheimer's as well as injuries to the brain or spinal cord," said Sakaguchi, who reported on the research on November 7 at the Society of Neuroscience's annual meeting in New Orleans.

In order to be able to follow the fate of transplanted stem cells, Sakaguchi, in collaboration with Harvard scientist Michael Young, engineered mice to produce enhanced green fluorescent protein in all its cells. Stem cells isolated from embryonic brains of these transgenic mice were then transplanted by intraocular injection into the eyes of Brazilian opossum pups of various ages (from 10 days to two years). The researchers determined the fate of transplanted cells by tracking GFP in sectioned eyes at various times following transplantation.

After only one week, GFP-expressing cells had not only been incorporated into the retina, but were expressing proteins characteristic of retinal cellsneurofilament protein, calretinin, and others. The researchers also found that the younger the animal was at the time of transplantation, the more highly differentiated the stem cells became.

"Experiments by other scientists have had limited success in integrating neural stem cells into adult animals," Sakaguchi said. "Our results suggest stem cells stand a better chance if they can be transplanted into an embryo-like environment."

Opossum neonates provide that kind of environment, as the opossum's pea-sized newborns are very immature.

Seven-day-old opossum pups attached to mother's nipples

"With the newborn opossum, we essentially have access to an embryonic stage of brain development," Sakaguchi said. "This makes the opossum a good model to study cellular connections in the brain as they become established."

The researchers will next try to identify the conditions in this embryo-like environment that enhance the survival and differentiation of stem cells. With this information, researchers can try to mimic the conditions so stem cells stand a better chance for use in adult animals. In the future, the researchers would like to transplant stem cells into animals with eye or other brain disorders to see whether the cells help treat the disease.

Abstract Number 415.2 and 415.2 Incorporation and differentiation of embryonic mouse stem cells transplanted into the mammalian retina. S.J. Van Hoffelen; A.M. Benediktsson; M.A. Shatos; M.J. Young; M.H. West Greenlee; D.S. Sakaguchi, Neuroscience Program, Iowa State University, Ames, Iowa, and Schepens Eye Research Institute, Harvard Medical School, Boston, MA.

Edited by Laura DeFrancesco Managing Editor, Bioresearch Online Email: ldefrancesco@bioresearchonline.com

Click here for more news from the Society for Neuroscience Annual Meeting.

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SOCIETY FOR NEUROSCIENCE NEWS: Mouse embryonic stem cells differentiate in opossum eyes - BioProcess Online