Image by Patrick Hoesly via FlickrResearchers for the first time have induced vigorous regeneration of nerve connections that control voluntary movement after spinal cord injury, revealing the possibility for new therapeutic treatments for paralysis and other motor function impairments.
In a study on lab rodents, University of California (UC) Irvine (UCI; USA), UC San Diego (UCSD; USA), and Harvard University (Cambridge, MA, USA) investigators achieved this breakthrough by turning back the developmental clock in a molecular pathway vital for the growth of corticospinal tract nerve connections. They did this by deleting an enzyme called a phosphatase and tensin homolog (PTEN), which controls a molecular pathway called mTOR that is a key regulator of cell growth. PTEN activity is low early during development, allowing cell proliferation. PTEN then turns on when growth is completed, suppressing mTOR and preventing any ability to regenerate.
Trying to find a way to restore early-developmental-stage cell growth in injured tissue, Dr. Zhigang He, a senior neurology researcher at Children’s Hospital Boston (MA, USA) and Harvard Medical School, first demonstrated in a 2008 study that blocking PTEN in mice enabled the regeneration of connections from the eye to the brain after optic nerve damage. He then collaborated with Drs. Oswald Steward of UCI and Binhai Zheng of UCSD to see if the same approach could promote nerve regeneration in injured spinal cord sites.