Schwann cells: development and role in nerve repair

Schwann cells develop from the neural crest in a well-defined sequence of events. This involves the formation of the Schwann cell precursor and immature Schwann cells, followed by the generation of the myelin and nonmyelin (Remak) cells of mature nerves. This review describes the signals that control the embryonic phase of this process and the organogene-sis of peripheral nerves. We also discuss the phenotypic plasticity retained by mature Schwann cells, and explain why this unusual feature is central to the striking regenerative potential of the peripheral nervous system (PNS). Themyelin and nonmyelin (Remak) Schwanncells of adult nerves originate from the neu-ral crest in well-defined developmental steps (Fig. 1). This review focuses on embryonic de-velopment (for additional information on myelination, see Salzer 2015). We also discuss how the ability to change between differentia-tion states, a characteristic attribute of develop-ing cells, is retained by mature Schwann cells