title: Prohibitin (PHB) acts as a potent survival factor against ceramide induced apoptosis in rat granulosa cells.
abstract: OBJECTIVE
  Ceramide is a key factor in inducing germ cell apoptosis by translocating from cumulus cells into the adjacent oocyte and lipid rafts through gap junctions. Therefore studies designed to elucidate the mechanistic pathways in ceramide induced granulosa cell (GC) apoptosis and follicular atresia may potentially lead to the development of novel lipid-based therapeutic strategies that will prevent infertility and premature menopause associated with chemo and/or radiation therapy in female cancer patients. Our previous studies have shown that Prohibitin (PHB) is intimately involved in GCs differentiation, atresia, and luteolysis.
  
  
  METHODS
  In the present study, we have examined the functional effects of loss-/gain-of-function of PHB using adenoviral technology in delaying apoptosis induced by the physiological ligand ceramide in rat GCs.
  
  
  RESULTS
  Under these experimental conditions, exogenous ceramide C-8 (50 μM) augmented the expression of mitochondrial PHB and subsequently cause the physical destruction of GC by the release of mitochondrial cytochrome c and activation of caspase-3. In further studies, silencing of PHB expression by adenoviral small interfering RNA (shRNA) sensitized GCs to ceramide C8-induce apoptosis. In contrast, adenovirus (Ad) directed overexpression of PHB in GCs resulted in increased PHB content in mitochondria and delayed the onset of ceramide induced apoptosis in the infected GCs.
  
  
  CONCLUSIONS
  Taken together, these results provide novel evidences that a critical level of PHB expression within the mitochondria plays a key intra-molecular role in GC fate by mediating the inhibition of apoptosis and may therefore, contribute significantly to ceramide induced follicular atresia.
authors.affiliation: Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, GA, USA.
authors.forename: Indrajit
authors.initials: I
authors.lastname: Chowdhury
authors.forename: Alicia
authors.initials: A
authors.lastname: Branch
authors.forename: Moshood
authors.initials: M
authors.lastname: Olatinwo
authors.forename: Kelwyn
authors.initials: K
authors.lastname: Thomas
authors.forename: Roland
authors.initials: R
authors.lastname: Matthews
authors.forename: Winston E
authors.initials: WE
authors.lastname: Thompson
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002518:Ceramides / Q000494:pharmacology*; D016895:Culture Media, Serum-Free; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D015870:Gene Expression; D006107:Granulosa Cells / Q000187:drug effects* / Q000648:ultrastructure; D008858:Microscopy, Phase-Contrast; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D000091402:Prohibitins; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D013997:Time Factors
chemical_list: D002518:Ceramides; D016895:Culture Media, Serum-Free; C000717332:Phb protein, rat; D000091402:Prohibitins; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D045304:Cytochromes c; D053148:Caspase 3