Abstract：
The steroidogenic activity of the granulosa cells is important for the reproductive cycle, and lipoproteins are involved in this process. The clathrin-mediated endocytosis pathway for LDL transport is considered to be the main one in eukaryotic cells. However, there are no studies that elucidate LDL internalization in human granulosa cells clarifying whether the clathrin-mediated endocytic pathway is functional in this process. The aim of this study is to investigate the role of clathrin and v-SNARE proteins in the formation of vesicles in human granulosa cells. In this study, the COV434 human granulosa cells were cultured and divided into four groups where in some of the groups Dil-conjugated LDL and Icarugamycin (ICA) a clathrin-mediated endocytosis inhibitor were added. From the collected mediums pregnenolone and progesterone levels were measured using ELISA. Oil red O staining was performed to show the intracellular lipids in the cells. Clathrin-coated vesicles believed to be responsible for carrying LDL, and v-SNARE proteins that direct the vesicles to their target molecules were also labeled and investigated by histological and ultrastructural methods. Our results show that human granulosa cells as well use the LDL cholesterol for steroid biosynthesis and they may prefer the clathrin-mediated endocytotic pathway to internalize it.
摘要：
颗粒细胞的类固醇生成活性对生殖周期很重要，脂蛋白参与了这个过程。网格蛋白介导的LDL转运途径被认为是真核细胞中的主要途径。然而,目前尚无研究阐明LDL在人颗粒细胞中的内化作用,从而阐明网格蛋白介导的内吞途径在此过程中是否起作用.这项研究的目的是研究网格蛋白和v-SNARE蛋白在人颗粒细胞囊泡形成中的作用。在这项研究中,培养COV434人颗粒细胞,并将其分为4组,其中一些组中加入了Dil-缀合的LDL和Icarugamin(ICA)-一种网格蛋白介导的内吞作用抑制剂.使用ELISA从收集的培养基中测量孕烯醇酮和孕酮水平。进行油红O染色以显示细胞中的细胞内脂质。被认为是携带低密度脂蛋白的包裹素的囊泡，还通过组织学和超微结构方法标记并研究了将囊泡引导至其靶分子的v-SNARE蛋白。我们的结果表明，人颗粒细胞也使用LDL胆固醇进行类固醇生物合成，他们可能更喜欢网格蛋白介导的内吞途径将其内化。
