Bioreactor Transient Exposure Activates Specific Neurotrophic Pathway in Cortical Neurons

Abstract

Altered gravity forces might influence neu- roplasticity and can provoke changes in biochemical mechanisms. In this contest, neurotrophins have a piv- otal role, particularly nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF). A suspen- sion of dissociated cortical cells from rat embryos was exposed to 24 h of microgravity before plating in nor- mal adherent culture system. Expression and transduc- tional signalling pathways of NGF and BDNF were assessed at the end of maturational process (8-10 days in vitro). Rotating wall vessel bioreactor (RWV) pre- exposition did not induce changes in NGF expression and its high affinity receptor TrkA. On the contrary both BDNF expression and its high affinity recep- tor TrkB were strongly up-regulated, inducing Erk- 5, but not Erk-1/2 activation and, in turn, MEF2C over-expression and activation. According to our pre- vious and present results, we postulate that relatively short microgravitational stimuli, applied to neural cells