title: Apoptosis of rat granulosa cells after staurosporine and serum withdrawal is suppressed by adenovirus-directed overexpression of prohibitin.
abstract: Prohibitin (Phb1) is a highly conserved mitochondrial protein that is associated with granulosa cell differentiation, atresia, and luteolysis. Although prohibitin has been implicated in the suppression of apoptosis in mammalian cells, its specific role in programmed cell death in granulosa cells is unknown. In the present study, we examined the role of prohibitin in mediating staurosporine (STS) and serum withdrawal induced apoptosis in undifferentiated rat granulosa cells. Treatment of granulosa cells isolated from immature rat ovaries with STS and/or serum withdrawal induced a rapid decrease in the transmembrane potential of mitochondria, resulting in increased prohibitin content and induced apoptosis in a time- and dose-dependent manner. Infection of granulosa cells with a Phb1 adenoviral construct resulted in overexpression of prohibitin that markedly attenuated the ability of STS and serum withdrawal to induce apoptosis via the intrinsic apoptotic pathway. To determine the site of action of Phb1, granulosa cells were transfected with a prohibitin-eGFP fusion construct, and the fusion protein expression patterns were analyzed by fluorescence microscopy and Western blot analysis of cell fractionated samples. These studies indicated that the prohibitin-eGFP fusion protein moved from the cytoplasm into the mitochondria. However, no prohibitin-eGFP fusion protein was observed in the nucleus in response to the STS-induced apoptotic stimulus. This result was corroborated by Western blot analysis with green fluorescent protein-specific antibody. Furthermore, the prohibitin-eGFP fusion protein also inhibited programmed cell death. These results provide evidence that prohibitin could serve an antiapoptotic role in undifferentiated granulosa cells.
authors.affiliation: Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Indrajit
authors.initials: I
authors.lastname: Chowdhury
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Stiles
authors.forename: Anthony
authors.initials: A
authors.lastname: Zeleznik
authors.forename: Xuebiao
authors.initials: X
authors.lastname: Yao
authors.forename: Roland
authors.initials: R
authors.lastname: Matthews
authors.forename: Kelwyn
authors.initials: K
authors.lastname: Thomas
authors.forename: Winston E
authors.initials: WE
authors.lastname: Thompson
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001798:Blood Proteins / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000502:physiology; D006107:Granulosa Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D008928:Mitochondria / Q000502:physiology; D010718:Phosphatidylserines / Q000378:metabolism; D000091402:Prohibitins; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000235:genetics*; D019311:Staurosporine / Q000494:pharmacology*; D014162:Transfection
chemical_list: D001798:Blood Proteins; D004791:Enzyme Inhibitors; D010718:Phosphatidylserines; D000091402:Prohibitins; D012097:Repressor Proteins; D045304:Cytochromes c; D053148:Caspase 3; D019311:Staurosporine