Co-expression of heat shock transcription factors 1 and 2 in rat retinal ganglion cells.

Heat shock protein (HSP) plays an important role in the maintenance of neuronal survival during harmful conditions. Previously, we reported that metabolic stress induces HSP72 in retinal ganglion cells (RGCs) and protects against excitotoxicity, hypoxia and experimental glaucoma. To understand heat shock protein transcriptional mechanisms, we examined the cellular expression of heat shock factors 1 (HSF1) and 2 (HSF2) in the unstressed adult rat retina. Western blotting, immunohistochemistry and RT-PCR showed that mRNA and protein of HSF1 and HSF2 were present in the rat retina and predominantly expressed in RGC layer cells. Western blotting of dissociated RGC suspensions harvested with Thy-1 immuno-labeled magnetic beads confirmed that RGCs expressed HSF1, HSF2 and HSP72. Our findings suggest that both heat shock transcription factors 1 and 2 are linked to the heat shock response in retinal ganglion cells.