Figure 1: The tissue response to myelin injury requires the coordination of various cells and signals.

(a) Healthy oligodendrocytes (OLs; light purple) identified by major myelin proteins MBP, PLP, and MOG extend processes that insulate axons (gray). Myelination enhances nerve activity, depicted by higher amplitude nerve impulses. (b) Myelin injury retards neuronal signaling and initiates phagocytic clearance of myelin debris by microglia. (c) OPCs, identified by A2B5, PDGFRα, and/or NG2, respond to distinct molecular cues that orchestrate migration, proliferation, and ultimately differentiation toward oligodendrocytes. (d) Pre-myelinating oligodendrocytes engage denuded axons. (e) Remyelination by newly-formed OLs and restoration of accelerated nerve activity completes the tissue response to myelin injury.