Growth hormone and cell survival in the neural retina: caspase dependence and independence.
Growth hormone has recently been shown to be expressed in the retinal ganglion cells of embryonic chicks, in which it induces cell survival during neurogenesis. The mechanism of this action has been examined in neural retina explants from 6-day-old and 8-day-old embryos that were incubated for 48 h in 10 M growth hormone, to reduce the number of spontaneous apoptotic cells. This anti-apoptotic action was accompanied by a reduction in caspase-3 expression and, at embryonic day 8, by reduced expression of apoptosis inducing factor-1, which is caspase independent. These actions were specific, as other genes involved in apoptotic signaling (bcl-2, bcl-x, bid and inhibitor of apoptosis protein-1) were unaffected. These results therefore demonstrate caspase-dependent and caspase-independent pathways in growth hormone-induced retinal cell survival.
Harvey
Steve
S
Department of Physiology, University of Alberta, Edmonton, Alberta, Canada. steve.harvey@ualberta.ca
Baudet
Marie-Laure
ML
Sanders
Esmond J
EJ
D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000096:biosynthesis; D053148:Caspase 3 / Q000096:biosynthesis / Q000502:physiology*; D002470:Cell Survival; D002642:Chick Embryo; D047108:Embryonic Development; D013006:Growth Hormone / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000201:enzymology*; D046509:Tissue Culture Techniques
D051033:Apoptosis Inducing Factor; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D013006:Growth Hormone; D053148:Caspase 3