Tau modulated Schwann cell proliferation, migration, and differentiation following peripheral nerve injury

Abstract

Microtubule-associated protein tau (MAPT) is essential for the assembly and stability of microtubule and the functional maintenance of the nervous system. Tau is abundant in neurons and detectable in astrocytes and oligodendrocytes. However, whether tau existed in Schwann cells, the unique glial cells in the peripheral nervous system, remains unclear. Here, we investigated the presence of tau and its coding gene MAPT in cultured Schwann cells and found the presence of tau. The gene-silencing of MAPT promoted Schwann cell proliferation and inhibited Schwann cell migration and differentiation. In vivo application of MAPT siRNA suppressed the migration of Schwann cells after sciatic nerve injury. Consistently, tau knockout mice showed elevated proliferation and reduced migration of Schwann cells. Rats injected with MAPT siRNA and tau knockout mice also exhibited impaired myelin and lipid debris clearance. The expressions and distributions of cytoskeleton proteins α-Tubulin and F-actin were disrupted as well. These findings demonstrated the existence and biological effects of tau on Schwann cells and expanded our understanding of the function of tau in the nervous system.