Researchers Generate New Neurons in Brains, Spinal Cords of Living Adult Mammals Without the Need of Stem Cell …

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Newswise DALLAS, Feb. 25, 2014 UTSouthwestern Medical Center researchers created new nerve cells in the brains and spinal cords of living mammals without the need for stem cell transplants to replenish lost cells.

Although the research indicates it may someday be possible to regenerate neurons from the bodys own cells to repair traumatic brain injury or spinal cord damage or to treat conditions such as Alzheimers disease, the researchers stressed that it is too soon to know whether the neurons created in these initial studies resulted in any functional improvements, a goal for future research.

Spinal cord injuries can lead to an irreversible loss of neurons, and along with scarring, can ultimately lead to impaired motor and sensory functions. Scientists are hopeful that regenerating cells can be an avenue to repair damage, but adult spinal cords have limited ability to produce new neurons. Biomedical scientists have transplanted stem cells to replace neurons, but have faced other hurdles, underscoring the need for new methods of replenishing lost cells.

Scientists in UTSouthwesterns Department of Molecular Biology first successfully turned astrocytes the most common non-neuronal brain cells into neurons that formed networks in mice. They now successfully turned scar-forming astrocytes in the spinal cords of adult mice into neurons. The latest findings are published today in Nature Communications and follow previous findings published in Nature Cell Biology.

Our earlier work was the first to clearly show in vivo (in a living animal) that mature astrocytes can be reprogrammed to become functional neurons without the need of cell transplantation. The current study did something similar in the spine, turning scar-forming astrocytes into progenitor cells called neuroblasts that regenerated into neurons, said Dr. Chun-Li Zhang, assistant professor of molecular biology at UTSouthwestern and senior author of both studies.

Astrocytes are abundant and widely distributed both in the brain and in the spinal cord. In response to injury, these cells proliferate and contribute to scar formation. Once a scar has formed, it seals the injured area and creates a mechanical and biochemical barrier to neural regeneration, Dr. Zhang explained. Our results indicate that the astrocytes may be ideal targets for in vivo reprogramming.

The scientists' two-step approach first introduces a biological substance that regulates the expression of genes, called a transcription factor, into areas of the brain or spinal cord where that factor is not highly expressed in adult mice. Of 12 transcription factors tested, only SOX2 switched fully differentiated, adult astrocytes to an earlier neuronal precursor, or neuroblast, stage of development, Dr. Zhang said.

In the second step, the researchers gave the mice a drug called valproic acid (VPA) that encouraged the survival of the neuroblasts and their maturation (differentiation) into neurons. VPA has been used to treat epilepsy for more than half a century and also is prescribed to treat bipolar disorder and to prevent migraine headaches, he said.

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Researchers Generate New Neurons in Brains, Spinal Cords of Living Adult Mammals Without the Need of Stem Cell ...

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