The Extracellular Matrix Protein 1 (ECM1) in Skin Biology: An Update for the Pleiotropic Action

Extracellular matrix protein 1 (ECM1) is a secreted glycoprotein that plays a pivotal role in the structural and homeostatic biology of the skin, particularly in angiogenesis, reconstitution of basement membrane, proliferation and differentiation of epidermal keratinocytes and dermal fibroblasts, and malignant transformation. This rationale is substantiated by loss-of-function mutations in the ECM1 gene in an autosomal recessive genodermatosis lipoid proteinosis and circulating IgG autoantibodies to this molecule in a humoral autoimmune condition lichen sclerosus, both of which are counterpart disease conditions sharing comparable skin pathology. In the recent decade, considerable progress has been made in determining the in vivo function of ECM1 in animal model studies. Furthermore, underlying insights arose for the genetic predisposition in inflammatory bowel disease ulcerative colitis, acquisition of immune tolerance and allergic responses via particular T cell subsets such as CD4+CD25+ regulatory T cells and Th2 cells, regeneration of certain organs, and clinical advantages for diagnostic and prognostic significance in various cancers. Following our latest review in 2009, we now update the most recent evidences for the pleiotropic action of ECM1 in skin research, and also highlight the novel pathogenic relevance of this molecule in a variety of human disorders.