Laminin Expression and Function in the Central Nervous System

ABSTRACT

Laminin, an extracellular matrix protein with multiple isoforms, is a key component of the basal lamina. In the central nervous system (CNS), different cells synthesize distinct laminin isoforms, which exert a diverse range of functions, including blood‐brain barrier maintenance/repair, cell survival/migration/differentiation, myelination, inflammatory cell extravasation, and brain injury modulation. However, the exact roles of distinct laminin isoforms synthesized by individual cell types remain incompletely understood. In this review, we discuss cell‐specific expression and function of laminin in the CNS. First, laminin isoforms synthesized by major vascular cells (brain microvascular endothelial cells, pericytes, and vascular smooth muscle cells) and parenchymal cells (astrocytes, neurons, oligodendrocytes) are summarized. Sparse evidence regarding laminin expression in perivascular fibroblasts and microglial is also included. Next, the functions of laminins on various cell types under both homeostatic and pathological conditions are described in detail. Functional redundancy and potential compensatory mechanisms are also reviewed. Finally, we discuss unanswered questions in the field and future research directions. This review provides a comprehensive framework of laminin expression and function in the CNS, which fosters novel hypotheses and catalyzes new avenues of research in matrix biology.