"You Have A Lot of Nerve"

Progress in neuroregeneration has offered potential to repair neural damages, recover neural function after injury and can lead to the development of new therapeutic techniques.

Dr. Jessica Brann visited our neuroscience seminar last month to discuss her study, which showed a new perspective in neuroregeneration. Neuroregeneration can tremendously aid the recovery process from traumatic brain injuries and/or any degenerative process of normal aging. The ability of the olfactory epithelium to generate sensory neurons continues into middle age in mice and is assumed that this ability to regenerate is possible in all developmental stages. However, there is not much sufficient evidence that supports that this ability to generate mature neurons exists into late adulthood. It has been known of the potential of basal stem cells to regenerate sensory neurons in the olfactory epithelium of young adults. Dr. Brann’s study attempts to further investigate neurogenesis in olfactory epithelium of aged adults.

One of the experiments done was to test the behavior of the horizontal basal cells, which are thought to be the primary stem cell population that supplies new cells. These stem cells normally enter an inactive phase during early post-natal stages. In order to test if these stem cells will renter an active phase and start generating new mature neurons, olfactory sensory neurons were purposely killed, something that would happen as a result of a traumatic brain injury or neurological disease. The once inactive horizontal basal cells, changed their shape and function to that of an active state. It was concluded that the basal stem cells in aged olfactory epithelium still has regenerative capability and can yield mature neurons.

An article from ScienceDaily talks about a study similar to that of Dr. Brann’s. However, this study puts more emphasis on the generation of neural stem cells. Rudolf Jaenisch, founder of Whitehead Institute for Biomedical Research, explains how “…it's important to make neural stem cells because they can self-renew and make lots of cells” and how “If you just make mature neurons, which has been done by others, you never get enough cells.”

Originally, viruses with specific transcription factors were inserted into the genome of adult mice skin cells and a specific drug activated these transcription factors, turning on genes in neural stem cells. However, the neural stem cells developed a dependency on the drug and transcription factors, and when removed, they went back to skin cells. After growing it in a special medium, scientist were able to create neural stem cells that remain in their active state and independent of the drugs and transcription factors. This allows the neural stem cells to repeatedly generate new cells effectively and available for use of therapy.

 Overall, both of these studies represent a huge breakthrough in neuroregeneration. The results from both studies provide valuable insight and open up new ideas and treatments to recover nerve functionality from traumatic injuries or neurodegenerative diseases.

Brann, Jessica H., Deandrea P. Ellis, Benson S. Ku, Eleonora F. Spinazzi, and Stuart Firestein. "Injury in Aged Animals Robustly Activates Quiescent Olfactory Neural Stem Cells." Front. Neurosci. Frontiers in Neuroscience9 (2015): n. pag. Web. 2 May 2016.

Whitehead Institute for Biomedical Research. "Direct Generation of Neural Stem Cells Could Enable Transplantation Therapy." ScienceDaily. ScienceDaily, n.d. Web. 04 May 2016. <https://www.sciencedaily.com/releases/2014/11/141106131518.htm>.