Neurotrophins in healthy and diseased skin

Neurotrophins (NT) belong to a family of structurally andfunctionally related proteins that, depending on the tissuecontext and the receptors involved, promote either neuronalcell survival and differentiation or cell death. NT, and inparticular NGF, were first identified as neurotrophic factorssupporting the synthesis and development of sensory neuronsin the central and peripheral nervous system. it is now widelyaccepted that NT also act as growth factors in non-neuronalcells, including the skin. in the skin, most cell types are ableto secrete and/or to respond to stimulation by NT, creatinga unique network of molecular signaling in the cutaneousmicroenvironment. Moreover, many skin diseases have beenassociated with an involvement of a number of neural factorsincluding NT, but less attention has been given to the role ofNT as growth factors in the development of skin pathologies.This review summarizes currently data on the expression andfunction of NT and their receptors in several cell types in theskin. Moreover it focuses on the role of the skin NT network intwo cutaneous conditions, melanoma and psoriasis where NTare clearly involved.