Prohibitin (PHB) acts as a potent survival factor against ceramide induced apoptosis in rat granulosa cells

Abstract

Aim 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. Main 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. Key findings Under these experimental conditions, exogenous ceramide C-8 (50μM) 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. Significance 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.

Prohibitin (PHB) roles in granulosa cell physiology

“…Our studies have shown that infection of undifferentiated GC from preantral follicles with a PHB adenoviral construct resulted in over-expression of PHB that markedly attenuated ceramide-, staurosporine-, campothecine- and serum withdrawl-induced apoptosis via the intrinsic apoptotic pathway (Chowdhury et al, 2007, 2011, 2013, 2014; Wang et al, 2013a,b; our unpublished data). Further, these studies have confirmed that over-expression of PHB maintains the mitochondrial transmembrane potential by inhibiting cytochrome c release and activation of caspase-3 (Chowdhury et al, 2007, 2011, 2013). …”

Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

“…The addition of 100 µM CER to rat lung cells and prostate cancer cells increased BAX, cytochrome C and caspase expressions (Husari et al, 2006). In addition, CER increased apoptosis, cytochrome C and capase-3 levels in cultures of rat granulosa cells (Chowdhury et al, 2011). Therefore, it is likely that CER could be involved in the granulosa cells apoptotic process that results in follicle atresia.…”

The Presence of HIV-1 Tat Protein Second Exon Delays Fas Protein-mediated Apoptosis in CD4+ T Lymphocytes

“…Other anti-apoptotic factors such as PHB contributed to the higher protection against apoptosis provided by Tat101 but not Tat72. PHB is a potent survival factor that inhibits the release of cytochrome c and caspase-3 activation (98,99), and it was increased 70-fold in Jurkat-Tat101, which was 2-fold higher than in Jurkat-Tat72.…”