Astrocytes induce proliferation of oligodendrocyte progenitor cells via connexin 47-mediated activation of Chi3l1 expression.

Abstract

Demyelinating neurodegenerative diseases are some of the most important neurological diseases that threaten the health of the elderly. Astrocytes (ASTs) play an important role in the regulation of the growth and development of oligodendrocytes (OLs) and oligodendrocyte progenitor cells (OPCs), which participate in remyelination. This study investigated the mechanism by which ASTs promote the proliferation of OPCs via connexin 47 (Cx47) in OPCs. Under direct-contact co-culture conditions, we performed Cx47 siRNA interference in ASTs and OPCs and tested the cell proliferation ability by flow cytometry and with 5-ethynyl-20-deoxyuridine (EdU). We then detected Chi3l1 expression by Western blotting and immunofluorescence. Next, after the addition of exogenous Chi3l1 protein to OPCs under monoculture conditions, we tested the cell proliferation ability by flow cytometry and EdU. After siRNA interference with Cx47, the expression of Chi3l1 decreased from 1.10±0.91 to 0.30±0.08, and the proportion of new OPCs decreased from 48.7±3.8% to 28.4±6.6%. Moreover, upon addition of exogenous Chi3l1 protein under OPCs mono-culture conditions, the expression of cyclin D1 increased from 0.68±0.09 to 1.16±0.14, leading to an increased number of OPCs in the S phase, from 7.37±1.38% to 13.55±1.60%. Cx47/Chi3l1 plays an important role in the promotion of OPCs proliferation by ASTs. ASTs can promote the expression of Chi3l1 via Cx47 in OPCs, and then activate the expression of cyclin D1 and regulate the cell cycle of OPCs, thereby promoting cell proliferation. This study provides a new target for the treatment of neurodegenerative diseases.