Regional differences of astrocyte response to neurotrophins

GONZALO MONTENEGRO; DANIEL MASCÒ; ANDREA BEATRÍZ CRAGNOLINI

Congreso; 29° Reunión de la Sociedad Argentina de investigación en Neurociencias; 2014

Astrocytes represent a heterogeneous population of cells whose responses may differ among brain regions. Reactive astrocytes proliferate and migrate toward the lesion and also release chemical mediators that includes neurotrophins (NTs). We have previously demonstrated that a brain injury induces the expression of the neurotrophic receptor (NTR) p75ntr on astrocytes which also mediates the anti-proliferative effect of NGF. The aim of this study was to assess the responses of astrocytes from different brain areas to NTs and evaluate how a brain lesion affect the expression of NTRs. In vivo, we observed that the stab wound lesion, induced p75ntr expression in brain tissues obtained from the areas surrounding the injury while the other BDNF receptor, truncated TrkB (TrkB-t), decreased. This change in the pattern of expression of NTRs could make the injured tissue sensitive to differents NTs. In cultured astrocytes from hippocampus (hip), cortex (cx) and striatum (st) we found that the mechanical injury (scratch) induced the expression of both, p75ntr and TrkB-t. When Astrocytes were injured and treated with NGF we found that astrocytes from hip, cx and st responded by migrating to the injured area. However, the treatment with BDNF induced migration but only in astrocytes from st. Taken together, these results showed that astrocytes have regional differences in terms of responses to neurotrophins which may serve to modulate different aspects of gliosis after mechanical injury.