The Role of Activins and Follistatins in Skin and Hair Follicle Development and Function

The document from 14 years ago reviewed the role of activins and follistatins in skin and hair follicle development and function. Activins and follistatins are part of the transforming growth factor β (TGFβ) superfamily, which plays a crucial role in the formation of hair follicles and associated appendages. Activins were initially identified as regulators of follicle stimulating hormone but their roles have expanded to include regulation of proliferation, differentiation, apoptosis, metabolism, homeostasis, immune function, wound repair and endocrine function in many tissues. Follistatins are soluble extracellular proteins which inhibit activin activity. The review emphasized the importance of these molecules in the epithelial/mesenchymal communication required for the development of normal hair follicles. Inappropriate expression of these molecules can have detrimental effects on skin and hair growth. The review also discussed the limited evidence regarding the involvement of activins and follistatin in the control of the hair cycle. Transgenic mice with inappropriate expression of components of the activin signalling pathways displayed a range of phenotypes suggesting important roles of activins, their receptors, binding proteins and nuclear response elements in skin and hair follicle neogenesis, hair follicle cycling, skin maintenance and wound healing.