Acid sphingomyelinase involvement in tumor necrosis factor {alpha}-regulated vascular and steroid disruption during luteolysis in vivo. Henkes LE et al. TNF is well known for its role in inflammation, including direct effects on the vasculature. TNF also is implicated in the regulation of reproduction by its actions to affect ovarian steroidogenic cells and to induce apoptosis of corpus luteum (CL)-derived endothelial cells in vitro. We hypothesized that the disruption of TNF signaling would postpone the regression of the highly vascularized CL in vivo, and this effect could be replicated in mutant mouse models lacking TNF receptor (TNFRI(-/-)) and/or a critical enzyme of TNF signaling, acid sphingomyelinase (ASMase(-/-)). In the current study, the treatment of pseudopregnant mice with the luteolytic mediator prostaglandin F2-alpha (PGF) significantly increased TNF in the ovaries when compared with saline-treated controls. Treatment with PGF also reduced serum progesterone (P4) concentrations and caused involution of the CL. However, pretreatment of pseudopregnant mice with Etanercept (ETA), a TNF-neutralizing antibody, inhibited the PGF-induced decrease in P4 and delayed luteal regression. A similar outcome was evident in pseudopregnant TNFRI(-/-) animals. Treatment of luteal microvascular endothelial cells (MVECs) with TNF provoked a significant increase in ASMase activity when compared with the corresponding controls. Furthermore, TNF-induced MVEC death was inhibited in the ASMase(-/-) mice. The ASMase(-/-) mice displayed no obvious evidence of luteal regression 24 h after treatment with PGF and were resistant to the PGF-induced decrease in P4. Together these data provide evidence that TNF plays an active role in luteolysis. Further studies are required to determine the deleterious effects of anti-inflammatory agents on basic ovarian processes.
Expression regulated by
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Ovarian localization
Granulosa, Luteal cells
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RNA interference targeting of sphingomyelin phosphodiesterase 1 protects human granulosa cells from apoptosis. Gao J et al. Aim: Sphingomyelin phosphodiesterase 1 (SMPD1) plays an essential role in initiating the female germ cell death signal. To evaluate whether RNA interference has potential as a new approach in germ cell protection, we tested the effect of SMPD1 knockdown on human granulosa cells in vitro. Methods: We designed and synthesized three small interference RNA (siRNA) sequences targeted on SMPD1 and transfected them into human luteinizing granulosa cells (hGC) in vitro. Forty-eight hours after transfecting with siRNAs, hGC were treated with mitomycin C (MMC) to induce apoptosis. mRNA was detected with quantitative RT-PCR and protein was detected with Western blot. Methyl thiazolyl tetrazolium (MTT) assay was used to measure cell survival rate and detection of apoptotic rate of cells with Annexin V-PI staining by flow cytometer (FCM). Study groups were compared with liposome (lipofectamine 2000), MMC control and negative control siRNA. Results: After treatment with siRNA targeted to SMPD1, significant SMPD1 suppression occurred. After knockdown expression of SMPD1, the survival rate of hGC increased from 32.3% to 40.3%, and the apoptosis rate decreased from 68.3% to 44%. Conclusion: siRNA targeted on SMPD1 can protect hGC cells from apoptosis. These results reveal SMPD1 as a significant and effective target site for RNAi in the protection of human germ cells, which may have a direct bearing on future therapeutic research.