ABSTRACT
OBJECTIVE: To investigate the effect of heat shock protein 10 (HSP10) on apoptosis induced by testosterone in granulosa cells (GCs) of mouse ovaries in order to define the possible roles of HSP10 in ovarian pathological development of polycystic ovarian syndrome (PCOS) and hyperandrogenic conditions. STUDY DESIGN: Cultured mouse ovarian GCs were treated with testosterone (10(-5) mol/l). Apoptosis was assessed using flow cytometry, and proliferation was assessed using the MTT assay. HSP10 expression in the treated GCs was detected by real-time polymerase chain reaction (PCR). HSP10 gene was downregulated in the cultured GCs by AdCMV-H1-SiRNA/HSP10 or overexpressed by AdCMV-HSP10. PD98059 [phosphorylated ERK (p-ERK) inhibitor] was used to treat GCs to induce a high apoptosis index. Critical apoptotic factors and proliferation factors, including P-ERK, Bcl-2, Bax, caspase 9, caspase 3 and Ki67, were monitored by real-time reverse transcriptase PCR (RT-PCR) and Western blot. RESULTS: Compared with the control group, the apoptosis index was higher (p<0.05) and HSP10 expression was lower (p<0.05) in the testosterone-treated groups. In the AdCMV-H1-SiRNA/HSP10-treated group, cell viability was decreased (p<0.05) and the cell cycle was arrested at G2. Expression of p-ERK, Bcl-2 and Ki67, and the Bcl-2:Bax ratio were lower, while expression of apoptotic factors, including Bax, caspase 9 and caspase 3, was higher (p<0.05). Compared with the control group, Bcl-2 expression in the GCs that overexpressed HSP10 was increased (p<0.05), while the reduction of p-ERK and Bcl-2 and the elevation of caspase 9 and caspase 3 induced by PD98059 were significantly suppressed (p<0.05). CONCLUSIONS: Hyperandrogenic conditions induced apoptosis of mouse GCs. Testosterone may have reduced HSP10 expression in GCs, leading to reduced Bcl-2 expression and increased Bax expression.
Subject(s)
Apoptosis/drug effects , Chaperonin 10/pharmacology , Granulosa Cells/drug effects , Testosterone/pharmacology , Animals , Cell Cycle/drug effects , Cell Survival/drug effects , Chaperonin 10/biosynthesis , Female , Granulosa Cells/metabolism , Mice , Proto-Oncogene Proteins c-bcl-2/biosynthesis , bcl-2-Associated X Protein/biosynthesisABSTRACT
OBJECTIVES: To study the roles of heat shock proteins10 (HSP10) in the regulation of mouse ovarian granulose cell (GC) apoptosis, and to further define the possible roles of HSP10 in the development of polycystic ovary syndrome (PCOS). METHODS: Mouse HSP10 small interfering RNA (siRNA) and recombinant adenoviruses overexpressing HSP10 were constructed and subsequently transfected into cultured mouse ovarian GCs. After an infection period of 48 h, the expression levels of the HSP10 gene in mouse GCs were confirmed by Western blot. The GCs were also assessed for apoptosis using flow cytometry and the TUNEL assay. Apoptosis of GCs overexpressing HSP10 was assessed by flow cytometry after cisplatin treatment. RESULTS: Compared with control group, the expression of HSP10 was decreased in mouse GCs infected with AdCMV-siRNA/HSP10, whereas mouse GCs infected with AdCMV-HSP10 showed increased HSP10 expression p < 0.05. Knock-down of HSP10 in mouse GCs significantly increased apoptosis (p < 0.05), whereas overexpression of HSP10 significantly suppressed apoptosis induced by cisplatin (p < 0.05). CONCLUSION: In the present primary study, we have successfully employed recombinant adenovirus technologies to modulate HSP10 gene expression in mouse GCs, and examined the effects on apoptosis. Our experiments have demonstrated that knock-down of HSP10 induces apoptosis of mouse ovarian GCs, whereas overexpression of HSP10 suppresses apoptosis. These findings suggested that HSP10 may play a role in the regulation of apoptosis of mouse ovarian GCs.
