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Li J, Gao H, Tian Z, Wu Y, Wang Y, Fang Y, Lin L, Han Y, Wu S, Haq I, Zeng S. Effects of chronic heat stress on granulosa cell apoptosis and follicular atresia in mouse ovary. J Anim Sci Biotechnol 2016; 7:57. [PMID: 27708774 PMCID: PMC5043540 DOI: 10.1186/s40104-016-0116-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 09/13/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heat stress is known to alter follicular dynamics and granulosa cell function and may contribute to the diminished reproductive efficiency commonly observed in mammals during the summer. Although several investigators have studied heat-induced ovarian injury, few reports have focused on the effects of chronic heat stress on ovarian function and the molecular mechanisms through which it induces ovarian injury. METHODS In Exp. 1, 48 female mice were assigned to a control or heat-stressed treatment. After exposure to a constant temperature of 25 °C for 7, 14, 21 or 28 d (n = 6) or to 42 °C for 3 h per d for 7, 14, 21 or 28 d (n = 6), the mice were euthanized and their ovaries were analyzed for follicular atresia, granulosa cell apoptosis, changes in the abundance of HSP70 protein and serum concentrations of estradiol. In Exp. 2, the expression of HSP70 and aromatase was quantified in antral follicles cultured in vitro at 37 or 42 °C for 24 h. In Exp. 3, granulosa cells from ovaries maintained at 37 or 41 °C for 2 h were analyzed for their expression of HSP70, Bim, caspase-3 and cleaved caspase-3. RESULTS In Exp. 1, body weight and food intake of heat-stressed mice decreased (P < 0.05) compared with control mice while the concentration of estradiol in serum was lower (P < 0.05) in heat-stressed mice than in control mice. Compared with control mice, the percentage of atretic follicles and the number of antral follicles with severe apoptotic signals were increased (P < 0.05) after 21 d of heat-stressed treatment. HSP70 protein was more abundant (P < 0.05) in heat-stressed mice than control mice. In Exp. 2, heat stress increased HSP70 and decreased aromatase proteins (P < 0.05) in antral follicles. In Exp. 3, TUNEL-positive granulosa cells from heat-stressed ovaries were observed concomitant with a significant increase in HSP70, Bim and cleaved caspase-3 protein. CONCLUSION Heat-stress in mice decrease estradiol in serum and aromatase in antral follicles but increased number of atretic follicles and granulosa cell undergoing apoptosis which may explain the decreased fertility commonly observed in heat-stressed animals.
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Affiliation(s)
- Jieyun Li
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Hui Gao
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Zhen Tian
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Yi Wu
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Yingzheng Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yuan Fang
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Lu Lin
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Ying Han
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Shuaishuai Wu
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - IhteshamUl Haq
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
| | - Shenming Zeng
- Laboratory of Animal Embryonic Biotechnology; National Engineering Laboratory for Animal Breeding; Key Laboratory of Animal Genetics, Breeding, and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China
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Wang XL, Wu Y, Tan LB, Tian Z, Liu JH, Zhu DS, Zeng SM. Follicle-stimulating hormone regulates pro-apoptotic protein Bcl-2-interacting mediator of cell death-extra long (BimEL)-induced porcine granulosa cell apoptosis. J Biol Chem 2012; 287:10166-10177. [PMID: 22235114 DOI: 10.1074/jbc.m111.293274] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The pro-apoptotic protein Bim (B-cell lymphoma-2 (Bcl-2)-interacting modulator of cell death) has recently been identified and shown to promote cell death in response to several stimuli. In this report, we investigated the role of Bim in porcine follicular atresia. Initially, Bim cDNA was cloned and characterized from porcine ovarian tissue. Porcine Bim had three alternative splicing variants (Bim-extra long, Bim-long, and Bim-short), all containing the consensus Bcl-2 homology 3 domain. We then found the Bim-extra long (Bim(EL)) protein, the most abundant isoform of Bim, was strongly expressed and co-localized with apoptotic (TUNEL-positive) granulosa cells from porcine atretic follicles. Furthermore, overexpression of Bim(EL) triggered apoptosis in granulosa cells. In primary granulosa cell cultures under basal conditions, we observed that Bim(EL) expression was dampened by treatment with follicle-stimulating hormone (FSH). The role of the PI3K/Akt pathway in the regulation of repression was clarified by the use of the PI3K inhibitor, LY294002, and by transfection with Akt siRNA. Forkhead Box Protein O3a (FoxO3a), a well defined transcriptional activator of Bim, was phosphorylated at Ser-253 and inactivated after FSH stimulation. Also, FSH abolished FoxO3a nuclear accumulation in response to LY294002. Finally, chromatin immunoprecipitation assays demonstrated that FoxO3a directly bound and activated the bim promoter. Taken together, we conclude that Bim(EL) induces porcine granulosa cell apoptosis during follicular atresia, and its expression is regulated by FSH via the PI3K/Akt/FoxO3a pathway.
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Affiliation(s)
- Xian-Long Wang
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193 and
| | - Yi Wu
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193 and
| | - Lu-Bin Tan
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193 and
| | - Zhen Tian
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193 and
| | - Jing-Hao Liu
- Laboratory Animal Centre, Peking University, Beijing 100871, China
| | - De-Sheng Zhu
- Laboratory Animal Centre, Peking University, Beijing 100871, China
| | - Shen-Ming Zeng
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193 and.
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Urbich C, Knau A, Fichtlscherer S, Walter DH, Brühl T, Potente M, Hofmann WK, de Vos S, Zeiher AM, Dimmeler S. FOXO-dependent expression of the proapoptotic protein Bim: pivotal role for apoptosis signaling in endothelial progenitor cells. FASEB J 2005; 19:974-6. [PMID: 15824087 DOI: 10.1096/fj.04-2727fje] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Endothelial progenitor cells (EPCs) contribute to postnatal neovascularization. Risk factors for coronary artery disease reduce the number of EPCs in humans. Since EPC apoptosis might be a potential mechanism to regulate the number of EPCs, we investigated the effects of oxidative stress and HMG-CoA-reductase inhibitors (statins) on EPC apoptosis. Atorvastatin, mevastatin, or VEGF prevented EPC apoptosis induced by H2O2. The antiapoptotic effect was reversed by inhibition of the PI3K/Akt pathway. Forkhead transcription factors (FOXO1, FOXO3a, FOXO4) exert proapoptotic effects and are phosphorylated and, thereby, inactivated by Akt. Therefore, we elucidated the involvement of forkhead transcription factors. Atorvastatin induced the phosphorylation of the predominant forkhead factor FOXO4 in EPCs. In addition, atorvastatin reduced the expression of the proapoptotic forkhead-regulated protein Bim in a PI3K-dependent manner. Consistently, overexpression of FOXO4 activated the Bim promoter as determined by reporter gene expression and stimulated the expression of Bim, resulting in an increased EPC apoptosis. Statins failed to prevent EPC apoptosis induced by overexpression of Bim or nonphosphorylatable FOXO4, suggesting that the protective effects of statins depend on this pathway. In summary, our results show that FOXO-dependent expression of Bim plays a pivotal role for EPC apoptosis. Statins reduce oxidative stress-induced EPC apoptosis, inactivate FOXO4, and down-regulate Bim.
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Affiliation(s)
- Carmen Urbich
- Molecular Cardiology, Department of Internal Medicine IV, University of Frankfurt, Frankfurt, Germany
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