REGULATION OF SPHINGOMYELIN PATHWAY IN THE CORPUS LUTEUM

黄体(CL)的主要功能是合成和合成 分泌孕酮，为子宫的建立提供平静 和维持妊娠。任何过早的功能中断 黄体的不规则性会导致流产 周期性，以及生殖效率的降低。抑制力 类固醇合成(功能回归)，以及最终的 细胞内稳态的破坏(结构退化)，是 统称为黄体溶解。最近，细胞因子 被牵连到黄体溶解的积极作用中；但确切的 它们诱导其细胞毒活性的机制尚不清楚。 演示了。最近的证据表明，细胞死亡的信号， 无论是通过TNFpha、IFNGamma、Fas配体还是其他与应激相关的 刺激，是通过鞘磷脂途径来调节的。同时，这些 同样的因素也与类固醇抑制和死亡有关。 是CL的。细胞因子激活酸性鞘氨酸酶的结果 神经酰胺水平升高。随后，应激诱导的神经酰胺 据信优先通过细胞质胁迫发出信号 激活的蛋白激酶(SAPK)是丝裂原激活的成员 蛋白激酶级联(MAPKs)。MAPK是一种细胞质酶 负责将电池表面产生的信号转换为 它们通过磷酸化来调节转录的细胞核 转录因子。我们假设细胞因子以及其他 细胞毒性刺激，将通过鞘磷脂启动细胞死亡 黄体细胞中的途径及其第二信使神经酰胺。此外， 随后神经酰胺的增加将激活SAPKs，这将 最终使特定的转录因子磷酸化，涉及到 细胞死亡，因此在从 类固醇合成对神经细胞结构退化的功能抑制作用 克莱。为了解决这一假设，我们提出了以下目标：(1) 确定特定的细胞因子是否参与调节 黄体退化的功能和结构方面激活了 鞘磷脂途径。(2)刻画多效性响应 细胞因子(肿瘤坏死因子α-干扰素-γ)，由相对变化决定 ERKs和/或SAPKs/JNK和(3)转录因子c-fos和c-jun 在黄体细胞中。(4)确定是否单独使用类固醇抑制 可以激活培养的牛黄体细胞中的鞘磷脂途径。 (5)确定Capase酶在神经氨酸活化中的作用。这个 实验将利用定义良好的牛黄体原代培养物 细胞，并采用免费的细胞和分子技术 解决目标问题。预计该项目将提供新的信息 黄体溶解过程中涉及的细胞机制。

The primary function of the corpus luteum (CL) is to synthesize and secrete progesterone to provide uterine quiescence for the establishment and maintenance of pregnancy. Any premature disruption in the function of the corpus luteum can result in a loss of pregnancy, irregular cyclicity, and a reduction in reproductive efficiency. The inhibition of steroid synthesis (functional regression), and the eventual disruption of cellular homeostasis (structural regression), is collectively described as luteolysis. More recently, cytokines have been implicated in an active role in luteolysis; yet the exact mechanisms by which they elicit their cytotoxic activity remains to be demonstrated. Recent evidence suggests that the signal for cell death, whether it be by TNFalpha, IFNgamma, FAS ligand or other stress-related stimuli, is mediated via the sphingomyelin pathway. Coincedently, these same factors have also been implicated in steroid inhibition and demise of the CL. Activation of the acid-sphingomyelinase by cytokines results in elevated ceramide levels. Subsequently, stress-induced ceramide is believed to preferentially signal through the cytoplasmic stress activated protein kinase (SAPK) a member of the mitogen activated protein kinase cascade (MAPKs). MAPKs are cytoplasmic enzymes responsible for translating the signal generated on the cell surface to the nucleus where they regulate transcription by phosphorylating transcription factors. We hypothesize that cytokines, as well as other cytotoxic stimuli, will initiate cell death via the sphingomyelin pathway and its second messenger ceramide in luteal cells. Furthermore, subsequent increases in ceramide will activate SAPKs which will ultimately phosphorylate specific transcription factors implicated in cellular demise and therefore play a role in the transition from functional inhibition of steroidogenesis to structural regression of the CL. To address this hypothesis we have proposed the following aims: (1) Determine if specific cytokines implicated in the regulation of the functional and structural aspects of luteal regression activate the sphingomyelin pathway. (2) Characterize the pleiotropic responses to cytokines (TNFalpha-INFgamma) as determined by the relative changes in ERKs and/or SAPKs/JNK and (3) the transcription factors c-fos and c-jun in luteal cells. (4) Determine whether or not steroid inhibition alone can activate the sphingomyelin pathway in cultured bovine luteal cells. (5) Determine the role of capase enzymes in ceramine activation. The experiments will utilize well defined primary cultures of bovine luteal cells and employ complimentary cellular and molecular techniques to address the aims. This project is expected to provide novel information on the cellular mechanisms involved in the process of luteolysis.