Physiology of LGR7 and LGR8 in Gonadal Tissues

性腺组织中 LGR7 和 LGR8 的生理学

• 批准号: 7055339
• 负责人: AARON JW HSUEH
• 金额: $ 28.14万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-06 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7055339
• 关键词: Leydig cells; SDS polyacrylamide gel electrophoresis; Sertoli cells; binding proteins; biological signal transduction; cell surface receptors; chimeric proteins; corpus luteum; cryptorchidism; enzyme linked immunosorbent assay; genetic polymorphism; germ cells; gonads; graafian follicles; hormone inhibitor; ligands; northern blottings; polymerase chain reaction; protein localization; protein structure function; radioimmunoassay; receptor expression; relaxin; steroid hormone receptor; terminal nick end labeling

DESCRIPTION (provided by applicant): The classic hormone relaxin belongs to a family of peptide hormones with a conserved two-chain structure. Extensive studies have demonstrated that relaxin plays important roles in female physiology during pregnant and nonpregnant states and a paralogous gene, INSL3, is important in male reproductive development. Although relaxin is produced by ovarian luteal cells whereas INSL3 is produced by testis Leydig cells as well as ovarian the cal and luteal cells, their physiological roles in the gonads are unclear. Earlier studies suggested the presence of relaxin and INSL3 binding sites in target tissues including the gonads. However, studies on the putative receptors for these ligands were limited due to difficulties involved in performing ligand-binding assays for these proteins expressed at low levels. Our recent studies demonstrated that relaxin activates the orphan receptors LGR7 and LGR8 whereas INSL3 specifically activates LGR8. In addition to demonstrating the role of cAMP pathways in LGR7 and LGR8 signaling, we generated the soluble ligand-binding ectodomain of LGR7 to serve as a functional antagonist. Treatment with the soluble ectodomain of LGR7 delayed parturition of pregnant mice. Here, we propose to analyze the domains of LGR7 and LGR8 that are important for receptor function by testing ligand signaling of chimeric receptors. Based on our findings of LGR8 variants in cryptorchid patients, we will further test INSL3 activation of a LGR8 variant. We have obtained preliminary data indicating the expression of LGR7 and LGR8 in the testis and ovary and propose to elucidate the physiological roles of LGR7 and LGR8 in gonadal physiology. We will characterize the expression of LGR7 and LGR8 in specific gonadal cell types and their responsiveness to relaxin and INSL3 based on cAMP production and other responses. We will use the soluble ectodomains of LGR7 and LGR8 as functional antagonists to demonstrate the physiological roles of relaxin and INSL3 in testis and ovarian physiology in vivo. The proposed studies should provide a better understanding on the role of relaxin-related hormones and LGR7 and LGR8 receptors in gonadal physiology and other reproductive processes.

描述（由申请人提供）：经典的激素松弛素属于具有保守双链结构的肽激素家族。大量研究表明，松弛素在怀孕和非怀孕状态下的女性生理学中发挥着重要作用，而旁系同源基因 INSL3 在男性生殖发育中也很重要。虽然松弛素是由卵巢黄体细胞产生的，而 INSL3 是由睾丸 Leydig 细胞以及卵巢和黄体细胞产生的，但它们在性腺中的生理作用尚不清楚。早期研究表明，包括性腺在内的靶组织中存在松弛素和 INSL3 结合位点。然而，由于对这些低水平表达的蛋白质进行配体结合测定存在困难，对这些配体的推定受体的研究受到限制。我们最近的研究表明，松弛素激活孤儿受体 LGR7 和 LGR8，而 INSL3 特异性激活 LGR8。除了证明 cAMP 通路在 LGR7 和 LGR8 信号传导中的作用之外，我们还生成了 LGR7 的可溶性配体结合胞外域作为功能拮抗剂。用 LGR7 可溶性胞外域治疗可延迟妊娠小鼠的分娩。在这里，我们建议通过测试嵌合受体的配体信号传导来分析对受体功能重要的 LGR7 和 LGR8 结构域。根据我们在隐睾患者中发现的 LGR8 变异，我们将进一步测试 LGR8 变异的 INSL3 激活。我们已经获得了表明 LGR7 和 LGR8 在睾丸和卵巢中表达的初步数据，并建议阐明 LGR7 和 LGR8 在性腺生理学中的生理作用。我们将基于 cAMP 产生和其他反应来表征 LGR7 和 LGR8 在特定性腺细胞类型中的表达及其对松弛素和 INSL3 的反应。我们将使用LGR7和LGR8的可溶性胞外域作为功能拮抗剂来证明松弛素和INSL3在体内睾丸和卵巢生理学中的生理作用。拟议的研究应该可以更好地了解松弛素相关激素以及 LGR7 和 LGR8 受体在性腺生理学和其他生殖过程中的作用。