Mechanisms underlie inverse gender discrepancy in ischemic protection

缺血保护中性别反向差异的机制

• 批准号: 7738824
• 负责人: Nian-Qing Shi
• 金额: $ 22.28万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7738824
• 关键词: Acute; Address; Age; Aging; Antibodies; Binding; Calcium; Cardiac; Cardiovascular Diseases; Cell membrane; Cells; Clinical Treatment; Complex; Couples; Data; Defect; Drug Delivery Systems; Estrogen Receptor 2; Estrogen Receptors; Estrogens; Event; Exhibits; Exons; Female; Future; Gender; Genes; Health; Heart; Heart Mitochondria; Incidence; Infarction; Inner mitochondrial membrane; Ion Channel; Ischemia; Ischemic Preconditioning; Knock-out; Knockout Mice; Lead; Life; Mediating; Membrane; Messenger RNA; Mitochondria; Molecular; Mus; Mutant Strains Mice; Myocardial Infarction; Myocardial Ischemia; Nature; Pathway interactions; Pattern; Physiological; Play; Positioning Attribute; Postmenopause; Potassium Channel; Premenopause; Prevention; RNA Splicing; Regulation; Relative (related person); Reperfusion Therapy; Research; Role; Scheme; Sex Characteristics; Signal Pathway; Structure; Testing; Transcript; Variant; base; improved; in vivo; insight; interest; male; member; mitochondrial K(ATP) channel; mouse model; mutant; novel; polarized cell; preconditioning; public health relevance; response; sulfonylurea receptor; Acute; Address; Age; Aging; Antibodies; Binding; Calcium; Cardiac; Cardiovascular Diseases; Cell membrane; Cells; Clinical Treatment; Complex; Couples; Data; Defect; Drug Delivery Systems; Estrogen Receptor 2; Estrogen Receptors; Estrogens; Event; Exhibits; Exons; Female; Future; Gender; Genes; Health; Heart; Heart Mitochondria; Incidence; Infarction; Inner mitochondrial membrane; Ion Channel; Ischemia; Ischemic Preconditioning; Knock-out; Knockout Mice; Lead; Life; Mediating; Membrane; Messenger RNA; Mitochondria; Molecular; Mus; Mutant Strains Mice; Myocardial Infarction; Myocardial Ischemia; Nature; Pathway interactions; Pattern; Physiological; Play; Positioning Attribute; Postmenopause; Potassium Channel; Premenopause; Prevention; RNA Splicing; Regulation; Relative (related person); Reperfusion Therapy; Research; Role; Scheme; Sex Characteristics; Signal Pathway; Structure; Testing; Transcript; Variant; base; improved; in vivo; insight; interest; male; member; mitochondrial K(ATP) channel; mouse model; mutant; novel; polarized cell; preconditioning; public health relevance; response; sulfonylurea receptor

DESCRIPTION (provided by applicant): Myocardial infarction (MI) is a major health problem worldwide due to its acute nature and lack of effective prevention schemes. Gender difference in ischemic protection exists, with relatively lower MI incidences in pre- menopausal females than age-matched males. Emerging evidence indicates that the female-specific advantage in ischemic protection is mediated by estrogen. In the ischemic protection network, KATP channels (KATP) are postulated to play protective roles, but their relative importance remains to be controversial. Composed by a Kir6.2 pore and an SUR2 regulatory subunit, KATP activity is recorded in cardiac sarcolemmal or mitochondrial inner membrane. Our recent data show that disrupting the SUR2 gene at an earlier exon 3 causes an early lethality and the mutants only lived 8 days. However, disrupting SUR2 at middle exons 12-16 interrupts the SUR2 long forms, but the novel SUR2 short forms remain expressed. We have identified 2 splice variants that are generated by a rare intra-exonic splicing (IES) event in SUR2 mRNA to produce transcripts encoding the 55-kDa SUR2 short forms in heart mitochondria. Characterization of SUR2 KO has revealed an inverse pattern of gender difference in cardioprotection. Completed tests in KO males show that they are constitutively protected, with reduced infarcts after ischemia, while KO females have larger infarcts and cannot be preconditioned. mRNA levels of both IES variants markedly increase in the preconditioned KO males but they reduce dramatically in the preconditioned KO females. This interesting discrepancy offers a new platform of using SUR2 mutant mice to investigate gender difference in ischemic protection. The proposed research intends to explore the molecular mechanisms underlying gender difference in cardioprotection in relation to KATP channels, especially mitochondrial KATP. We hypothesized that estrogen modulates expression of sarcolemmal and mitochondrial SUR2 forms in mice. We further hypothesized that levels of the IES variants encoding the mitochondrial SUR2 short forms are critical to protection. In Aim 1, we will characterize ischemic protection in both genders of WT and KO mice, and study whether estrogen modulates expression of the SUR2 forms. In Aim 2, estrogen regulation in mitochondrial SUR2 will be investigated, and a 55A "rescued" female mouse model will be tested whether we can improve protection. Interactions of estrogen receptor 2 and the IES variants will be explored. Results from this research not only provide new insights in gender-specific response to cardioprotection but also identify new drug targets for future clinical treatments against MI. PUBLIC HEALTH RELEVANCE: The proposed research will employ KATP channel mutant mice that are defective in the sulfonylurea receptor 2 (SUR2) to evaluate gender difference in ischemic protection, regulation of estrogen in sarcolemmal and mitochondrial SUR2 forms and obtain new insights in ion channel regulation in cardiovascular diseases.

描述（由申请人提供）：由于其敏锐的性质和缺乏有效的预防方案，心肌梗塞（MI）是全球主要的健康问题。缺血性保护的性别差异与年龄匹配的男性相比，绝经前女性的MI发病率相对较低。新兴的证据表明，缺血性保护的女性特异性优势是由雌激素介​​导的。在缺血性保护网络中，假定KATP渠道（KATP）扮演保护角色，但其相对重要性仍然是有争议的。由KIR6.2孔和SUR2调节亚基组成，KATP活性记录在心脏肌膜或线粒体内膜中。我们最近的数据表明，在较早的外显子3上破坏SUR2基因会引起早期的致死性，而突变体仅活了8天。然而，在12-16中，在中部外显子上破坏SUR2会中断SUR2长形式，但新颖的SUR2短形式仍然表达。我们已经确定了2个剪接变体，这些变体是由SUR2 mRNA中罕见的外观测（IES）事件产生的，以产生编码心脏线粒体中55 kDa SUR2短形式的转录本。 SUR2 KO的表征揭示了心脏保护性别差异的逆模式。在KO雄性中完成的测试表明，它们受到组成性保护，缺血后梗塞减少，而KO雌性具有较大的梗塞，无法预处理。两种IES变体的mRNA水平在预处理的KO雄性中显着增加，但在预处理的KO女性中会大大降低。这种有趣的差异为使用SUR2突变小鼠的新平台提供了研究缺血性保护的性别差异。拟议的研究旨在探讨与KATP通道有关的心脏保护性别差异的分子机制，尤其是线粒体KATP。我们假设雌激素调节小鼠中肌膜和线粒体SUR2形式的表达。我们进一步假设编码线粒体SUR2短形式的IES变体的水平对于保护至关重要。在AIM 1中，我们将在WT和KO小鼠的性别中表征缺血性保护，并研究雌激素是否调节SUR2形式的表达。在AIM 2中，将研究线粒体SUR2中的雌激素调节，并将测试55A“救出”女小鼠模型，我们是否可以改善保护。将探索雌激素受体2和IES变体的相互作用。这项研究的结果不仅为性别特定对心脏保护的反应提供了新的见解，而且还确定了针对MI的未来临床治疗的新药物靶标。公共卫生相关性：拟议的研究将采用在磺酰脲受体2（SUR2）中有缺陷的KATP通道突变小鼠，以评估缺血性保护的性别差异，调节肌膜和线粒体SUR2形式中雌激素的调节，并在心血管疾病中的离子通道调节新见解。