The role and mechanism of activin A in neurite outgrowth of embryonic dorsal root ganglia of chicken

Abstract

Activin A, a member of transforming growth factor β (TGF-β) superfamily, plays essential role in neuron survival as a neurotrophic and neuroprotective factor in central nervous system. However, the effects and mechanisms of activin A on the neurite outgrowth of dorsal root ganglia (DRG) remain unclear. In the present study, we found that activin A is expressed in DRG collected from chicken embryos on day 8 (E8). Moreover, activin A induced neurite outgrowth of the primary cultured DRG and maintained long-time survival of monolayer-cultured DRG neurons during the observation for 10 days. Follistatin (FS), an activin-binding protein, significantly inhibited activin A-induced neurite outgrowth of DRG, but fails to influence the effect of nerve growth factor (NGF) on DRG neurite outgrowth. Furthermore, the results showed that activin A significantly up-regulated mRNA expressions of activin receptor type IIA (ActRIIA) and calcitonin gene-related peptide (CGRP) in DRG, and stimulated serotonin (5-HT) production from DRG, indicating that activin A may induce DRG neurite outgrowth via promoting CGRP expression and stimulating 5-HT release. These data suggest that activin A plays an important role in the development of DRG by autocrine/paracrine manner.