Abstract:

Galectin-3 (Gal-3) in oligodendrocyte (OLG) differentiation: OLGs are the cells in charge of myelination in the central nervous system (CNS), allowing rapid conduction of the neural action potential and giving trophic support to axons. OLGs undergo a series of changes throughout their life cycle: first, upon neural stem cell commitment to the OLG lineage, cells referred to as OLG precur sor cells (OPC) present a bipolar morphology, have proliferative and migratory capacity and express molecular markers like platelet-derived growth factor receptor alpha and neural/glial antigen 2;  next, in an intermediate stage called preOLG, OLGs are more ramified and express CNPase, Olig1 and O4, among others; finally, cells develop into myelin forming cells which express molecular markers like myelin basic protein (MBP), adenomatous polyposis polyposis and proteolipid protein. Worth pointing out, the actin cytoskeleton plays an important role in OLG maturation, as it evolves from pro-polymerization to pro-depolymerization dynamics, which allows axon ensheathing. These mechanisms are controlled in part by the relationship between MBP and actin disassembly proteins such as cofilin-1 and gelsolin. The latter are normally sequestered and inactivated by phosphatidylinositol 4,5-bisphosphate present in the plasma membrane. When MBP is expressed in mature OLG, it competes with gelsolin and cofilin-1 for phosphatidylinositol 4,5-bisphosphate binding, displacing and hence activating them, to trigger the disassembly of actin filaments.