Identification of Relaxin Receptor Antagonists

松弛素受体拮抗剂的鉴定

• 批准号: 6815923
• 负责人: SHEAU-YU Teddy HSU
• 金额: $ 18.92万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-10 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6815923
• 关键词: analog; birth; cell line; cell surface receptors; drug discovery /isolation; gene mutation; hormone receptor; inhibitor /antagonist; nucleic acid sequence; polymerase chain reaction; protein structure function; receptor binding; receptor expression; relaxin; reproductive development; transfection

DESCRIPTION (provided by applicant): Relaxin is a heterodimeric peptide hormone produced by the corpus luteum, decidua, and placenta in pregnant and nonpregnant females attaining the highest plasma levels during pregnancy. Other than its role in the inhibition of uterine contractile activity, relaxin has been shown to effect the induction of collagen remodeling and the consequent softening of the tissues of the birth canal (cervix and vagina), growth and differentiation of the mammary gland, and dilation of the blood vessels. Thus, relaxin plays a significant role in the overall regulation of physiological adaptation during pregnancy. Based on: primary and secondary structural characteristics, relaxin was grouped with insulin and insulin-like growth factors (IGFs) as a structural homolog. Analogous to insulin, prorelaxin, the precursor form of relaxin, has a domain arrangement similar to insulin and IGF precursors; mature relaxin appears to be processed by convertases to generate a two-chain heterodimer from the prorelaxin. In addition to two almost identical relaxin genes in human, there are five additional relaxin family genes including those encoding INSL3/RLF, INSIA/EPIL, INSL5/RIF2, INSL6/RIF1, and relaxin3. Passive immunization with anti-relaxin antibodies during the anteparmm period reduces cervical growth and extensibility as well as disrupts birth in rodents. In addition, numerous studies have shown that serum relaxin is an independent predictor of the risk of preterm delivery at multiple stages of pregnancy in humans. These earlier studies have propelled the proposition that a reduction of relaxin activity through receptor antagonists or immunization could be important for the treatment of preterm labor and birth in conjunction with traditional methods targeting other signaling pathways. Our recent studies have established that relaxin activates two orphan G protein-coupled receptors, LGR7 and LGR8 (Hsu et al., 2002. Science 295:671-4) as well as the cAMP-dependent pathway in target cells, whereas the closely related relaxin3 and INSL3 are selective agonists for LGR7 and LGR8, respectively. To take advantage of these new findings in relaxin signaling for the benefit of reproductive health research, we propose to screen for mutant recombinant relaxin antagonists that retain receptor-binding activity while being devoid of receptor-activation activity. Once mutant peptides with only the receptor binding activity are obtained, the antagonistic effect of these peptides will be tested in co-treatment assays to determine whether the mutant peptides are capable of antagonizing the relaxin-induced cAMP production in LGR7- and LGR8- expressing cells as well as delaying parturition in pregnant rats in vivo. These antagonists could be used to block relaxin action during preterm labor as well as provide a tool for further research on the role of LGR7 and LGR8 in reproductive tract physiology.

描述（由申请人提供）：松弛素是一种异二聚体肽激素，由怀孕和非怀孕女性的黄体、蜕膜和胎盘产生，在怀孕期间达到最高血浆水平。除了其在抑制子宫收缩活动中的作用之外，松弛素还显示出影响胶原蛋白重塑的诱导和随后的产道组织（子宫颈和阴道）软化、乳腺的生长和分化以及血管扩张。因此，松弛素在妊娠期间生理适应的整体调节中起着重要作用。依据：根据一级和二级结构特征，将松弛素与胰岛素和胰岛素样生长因子（IGF）归类为结构同源物。与胰岛素类似，松弛素原（松弛素的前体形式）具有类似于胰岛素和IGF前体的结构域排列;成熟松弛素似乎被转化酶加工以从松弛素原产生双链异源二聚体。在人类中除了两个几乎相同的松弛素基因之外，还有另外五个松弛素家族基因，包括编码INSL 3/RLF、INSIA/EPIL、INSL 5/RIF 2、INSL 6/RIF 1和松弛素3的那些。 在分娩前阶段用抗松弛素抗体进行被动免疫可降低啮齿类动物的宫颈生长和伸展性，并干扰分娩。此外，许多研究表明，血清松弛素是人类妊娠多个阶段早产风险的独立预测因子。这些早期的研究推动了这样一个命题，即通过受体拮抗剂或免疫来降低松弛素活性，结合针对其他信号通路的传统方法，对于治疗早产和分娩可能是重要的。我们最近的研究已经确定松弛素激活两种孤儿G蛋白偶联受体LGR 7和LGR 8（Hsu et al.，2002. Science 295：671-4）以及靶细胞中的cAMP依赖性途径，而密切相关的松弛素3和INSL 3分别是LGR 7和LGR 8的选择性激动剂。为了利用这些新发现的松弛素信号的生殖健康研究的好处，我们建议筛选突变重组松弛素拮抗剂，保留受体结合活性，而没有受体激活活性。一旦获得仅具有受体结合活性的突变肽，将在共处理测定中测试这些肽的拮抗作用，以确定突变肽是否能够拮抗LGR 7-和LGR 8-表达细胞中松弛素诱导的cAMP产生以及延迟体内妊娠大鼠的分娩。这些拮抗剂可用于阻断松弛素在早产过程中的作用，并为进一步研究LGR 7和LGR 8在生殖道生理学中的作用提供工具。