Gelsolin is required for macrophage recruitment during remyelination of the peripheral nervous system

Reorganization of the actin cytoskeleton is necessary for Schwann cell proliferation, migration and for the morphological changes associated with sorting, ensheathing and myelination of axons. Such reorganization requires regulated severing and depolymerization of actin filaments. Gelsolin is an actin filament severing protein expressed in many cell types including Schwann cells. Using Gelsolin knockout mice, we investigated the role of this protein in the myelination and remyelination of the peripheral nervous system. Our results show that although gelsolin is not necessary for developmental myelination, it is required for timely remyelination of the sciatic nerve following crush injury. Gelsolin is necessary for macrophage motility in culture, and its absence is likely to impair the recruitment of macrophages to the injury site.