N-cadherin-mediated human granulosa cell adhesion prevents apoptosis - A role in follicular atresia and luteolysis?
N-cadherin-mediated human granulosa cell adhesion prevents apoptosis - A role in follicular atresia and luteolysis?
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DOI：
10.1016/s0002-9440(10)65393-x
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发表时间：
1999-05-01
影响因子：
6
通讯作者：
Coutifaris, C
中科院分区：
文献类型：
--
作者：
Makrigiannakis, A;Coukos, G;Coutifaris, C
研究表明，细胞间的相互作用可以调节细胞凋亡，特别是，钙依赖性细胞粘附分子N-钙粘蛋白已被证明能够调节这一过程。已知大鼠颗粒细胞（GC）表达N-钙粘蛋白，而已知cAMP在人和大鼠GC中诱导细胞凋亡。基于这些观察结果，我们假设N-钙粘蛋白通过cAMP依赖性机制调节人GC凋亡，利用免疫组织化学技术评估卵泡和黄体中的N-钙粘蛋白表达，并利用免疫印迹、流式细胞术分析、免疫组织化学、和间接免疫荧光技术，利用抗N-针对该分子的细胞外和细胞质结构域的钙粘蛋白抗体。凋亡通过TUNEL和DNA片段化分析进行评估，并通过流式细胞术细胞周期分析和电子显微镜证实。GC凋亡率被认为是两到三倍之间的聚集细胞，与单细胞相比。N-cadherin在体外聚集的GCs中表达，在N-cadherin功能破坏抗体或肽的存在下培养的GCs表现出更高的凋亡率，在窦前和正常生长的排卵前卵泡以及早期黄体的GCs中N-cadherin原位染色强烈，在闭锁卵泡和退化黄体中N-cadherin弱。GC暴露于cAMP增加细胞凋亡，同时以剂量依赖性方式降低N-钙粘蛋白表达。无血清条件下的细胞培养增加了细胞凋亡，降低了N-钙粘蛋白的表达，部分是通过切割分子的胞外结构域。金属蛋白酶抑制剂1-10-菲咯啉抑制N-钙粘蛋白的胞外结构域的切割，并伴随抑制聚集的GC的血清剥夺诱导的细胞凋亡。总的来说，这些观察结果表明，N-钙粘蛋白的下调或该分子的功能性胞外结构域的缺失防止细胞聚集，并与GC细胞凋亡相关。cAMP以剂量依赖性方式诱导细胞凋亡，并且该过程至少部分依赖于细胞表面的N-钙粘蛋白分子的调节。我们得出结论，N-钙粘蛋白介导的GC信号传导在卵泡和黄体细胞存活中起核心作用。
Studies suggest that cell-cell interactions may regulate apoptosis, and in particular, the calcium-dependent cell adhesion molecule N-cadherin has been shown to be capable of modulating this process. Rat granulosa cells (GCs) are known to express N-cadherin whereas cAMP is known to induce apoptosis in human and rat GCs. Based on these observations, we hypothesized that N-cadherin regulates human GC apoptosis via a cAMP-dependent mechanism, N-cadherin expression was evaluated in ovarian follicles and corpora lutea utilizing immunohistochemical techniques and in luteinized GCs in culture using immunoblotting, flow cytometric analysis, immunohistochemistry, and indirect immunofluorescence techniques utilizing anti-N-cadherin antibodies directed against both the extracellular and cytoplasmic domains of the molecule. Apoptosis was assessed by TUNEL and DNA fragmentation analysis and confirmed by flow cytometric cell cycle analysis and electron microscopy. The rate of GC apoptosis was found to be two- to three-fold lower among aggregated cells, as compared with single cells. N-cadherin was found to be expressed by aggregating GCs in vitro and GCs cultured in the presence of either N-cadherin function disrupting antibodies or peptides exhibiting enhanced rates of apoptosis, GCs in situ stained intensely for N-cadherin in preantral and normal growing preovulatory follicles as well as early corpora lutea, N-cadherin was weak in atretic follicles and regressing corpora lutea. Exposure of GCs to cAMP increased apoptosis while decreasing N-cadherin protein expression in a dose-dependent manner. Cell culture under serum-free conditions increased apoptosis and decreased N-cadherin expression, in part through cleavage of the extracellular domain of the molecule. The metalloproteinase inhibitor 1-10-phenanthroline inhibited the cleavage of the extracellular domain of N-cadherin and concomitantly inhibited the serum-deprivation-induced apoptosis of aggregated GCs, Collectively, these observations suggest that down-regulation of N-cadherin or the absence of a functional extracellular domain of the molecule prevents cell aggregation and is associated with GC apoptosis, In addition, cAMP induces apoptosis in a dose-dependent manner, and this process is dependent, at least in part, on regulation of the N-cadherin molecule at the surface of the cells, We conclude that N-cadherin-mediated GC signaling plays a central role in follicular and luteal cell survival.