HYALURONIC ACID SYNTHESIS BY OVARIAN CUMULUS AND GRANULOSA CELLS

这个项目的目的是研究生物和生物化学 参与合成和组织透明质酸的过程- 丰富的细胞外基质，围绕大多数哺乳动物的卵母细胞， 排卵时间 该矩阵主要由 大约1,000个最初紧密粘附的卵丘细胞 到卵母细胞 为了响应促性腺激素激增，这些细胞启动 透明质酸合成并将其存款在细胞外基质中。 这一过程扩大了卵丘细胞-卵母细胞复合体， 膨胀的复合体在大约10小时后排卵。 我们 在体外用小鼠卵丘细胞-卵母细胞复合体研究这一过程。 已经确定了三个扩展所必需的因素：（1） 一种由卵母细胞产生的诱导透明质酸的可溶性因子 （2）FSH（或cAMP），其放大合成反应，和 (3)血清中的一种因子，需要保留新合成的透明质酸 基质中的酸。 我们已经证明：a）血清因子，鉴定为 作为一种α-胰蛋白酶间抑制剂，必须连续 存在以最大限度地保留新合成的透明质酸， 基质，B）透明质酸的十糖而不是八糖， 取代HA并防止基质形成，c）相反，一旦形成， 十碳碳化物不促进基质分解，和d） 内源性合成的45 kDa蛋白质与透明质酸结合 在基质形成过程中。 目前感兴趣的主题包括：（1） 鉴定由卵母细胞产生的诱导所需的因子， 透明质酸合成，（2）确定卵丘细胞如何响应 通过第二信使系统，（3）识别 通过免疫学和分子生物学方法， 探针，和（4）确定该蛋白质在基质形成中的作用。

The purpose of this project is to study the biological and biochemical processes involved in synthesizing and organizing the hyaluronic acid- rich extracellular matrix which surrounds most mammalian oocytes at the time of ovulation. This matrix is produced primarily by the approximately 1,000 cumulus cells which are initially closely adherent to the oocyte. In response to a gonadotropin surge these cells initiate hyaluronic acid synthesis and deposit it in the extracellular matrix. This process enlarges the cumulus cell-oocyte complex, and the fully expanded complex is ovulated approximately 10 hours later. We are studying this process with mouse cumulus cell-oocyte complexes in vitro. Three factors have been identified that are necessary for expansion: (1) a soluble factor produced by the oocyte which induces hyaluronic acid synthesis, (2) FSH (or cAMP) which amplifies the synthetic response, and (3) a factor in serum required to retain the newly synthesized hyaluronic acid in the matrix. We have shown that: a) the serum factor, identified by others as an inter-alpha-trypsin inhibitor, must be continuously present to maximize retention of newly synthesized hyaluronic acid in the matrix, b) decasaccharides but not octasaccharides of hyaluronic acid can displace the HA and prevent matrix formation, c) conversely, once formed decassacharides do not facilitate matrix disassembly, and d) an endogenously synthesized 45 kDa protein binds to the hyaluronic acid during matrix formation. Topics of present interest include: (1) identifying the factor produced by the oocyte that is required to induce hyaluronic acid synthesis, (2) determining how the cumulus cells respond to this factor via second messenger systems, (3) identifying the approximately 45 kDa protein by immunological and molecular biological probes, and (4) determining the role of this protein in matrix formation.