New GABAergic Interneurons Supported by Myelin-specific T Cells are Formed in Intact Adult Spinal Cord

¹ Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel

^* To whom correspondence should be addressed. E-mail: michal.schwartz{at}weizmann.ac.il.

	Abstract

Neural stem/progenitor cells are known to exist in the intact spinal cord, but the presence of newly formed neurons during adulthood has not been documented there to date. Here, we report the appearance of newly formed neurons under normal physiological conditions. These neurons are immature, express a GABAergic phenotype, and are primarily located in the dorsal part of the spinal cord. This localization appeared to be mediated by SDF-1/CXCR-4 signaling in the dorsal region. The extent of spinal cord neurogenesis was found to be greatly influenced by immune system integrity, and in particular by myelin-specific T cells. These observations provide evidence for in-vivo spinal cord neurogenesis under non-pathological conditions, and introduce novel mechanisms regulating adult spinal cord plasticity.