The regulation of Sox2 and Sox9 stimulated by ATP in spinal cord astrocytes.

After spinal cord injury (SCI), the level of adenosine triphosphate (ATP) and extracellular matrix (ECM) is increased. Formation of the glial scar is a complex process that is primarily attributed to astrocytic proliferation, and the fibrotic scar results from ECM deposition. In our previous researches, ATP and fibronectin was able to separately stimulate the proliferation of astrocytes. Moreover, fibronectin increases the expression of P2Y1 receptor and offers more binding sites for ATP, which aggravates the proliferation. Meanwhile, ATP was also able to stimulate the release of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α), but fibronectin does not. Recently, it has been reported that over-expressing P2Y1 receptor could promote the level of Sox9. However, the regulation of Sox genes by ATP is still little known in spinal cord astrocytes. In the present study, we discovered that ATP was able to increase the expression of Sox2 and Sox9; fibronectin did not have this direct function. Sox9 was only involved in the proliferation increased by ATP, and Sox2 influenced the release of IL-6 stimulated by ATP. Understanding the critical role of Sox2 and Sox9 mediated by ATP may provide a potential target for therapeutic intervention in spinal cord injury.