Researchers report that they have created new nerve cells in the brains and spinal cords of living mammals, without the need for stem cell transplants. The researchers, who are based out of UT Southwestern Medical Center’s department of Molecular Biology, first found success in turning astrocytes into neurons that formed networks in mice. Presently, they have turned scar-forming astrocytes in the spinal cords of adult mice into neurons.
Chun-Li Zhang, PhD, senior author of both studies, assistant professor of molecular biology notes, that in the researchers’ earlier work, it showed “in vivo 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.”
According to a news release from UT Southwestern, in the current study researchers first introduced a biological substance that regulates the expression of genes into areas of the brain or spinal cord where that factor is not highly expressed in adult mice. Among the 12 transcription factors tested, Zhang notes, only SOX2 switched fully differentiated, adult astrocytes to an earlier neuronal precursor, or neuroblast, stage of development.
As a second step, the release states, researchers gave the mice a treatment called valproic acid (VPA) designed to promote the survival of the neuroblasts and their maturation into neurons. According to Zhang, neurogenesis occurred in the spinal cords of both adult and aged mice (more than one year old) of both sexes, though the response was much weaker in the aged mice.
The release notes that researchers are now targeting strategies to boost the number and speed of neuron creation. They explain that neuroblasts took 4 weeks to form and 8 weeks to mature into neurons, slower than neurogenesis reported in lab dish experiments. The researchers reportedly plan to conduct experiments intended to pinpoint if a slower pace helps the newly generated neurons properly integrate into their environment.
Zhang adds that during the spinal cord study, SOX2-induced mature neurons created from reprogramming astrocytes persisted for 210 days following the start of the experiment.
Photo Caption: Zhang, left, and Zhida Su, a UT Southwestern visiting instructor of molecular biology from the Second Military Medical University in Shanghai, China.
Photo Credit: UT Southwestern Medical Center
Source: UT Southwestern Medical Center