The Role of Sulfonylurea Receptor 2 Splice Variants in Myocardial Function

磺酰脲类受体 2 剪接变体在心肌功能中的作用

• 批准号: 7752911
• 负责人: John P Fahrenbach
• 金额: $ 4.72万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7752911
• 关键词: ATP sensitive potassium channel complex; Abbreviations; Adult; Affect; Alternative Splicing; Arrhythmia; Attenuated; Binding; Birth; Blood Vessels; Breeding; Calcium; Cardiac; Cardiac Myocytes; Cell Survival; Cells; Cellular Stress; Cellular Stress Response; Coronary artery; Data; Development; Diabetes Mellitus; Drug usage; Endoplasmic Reticulum; Exhibits; Exons; Family; Functional disorder; Genes; Goals; Heart; Homeostasis; Hydrogen Peroxide; Ischemic Preconditioning; Laboratories; Length; Light; Link; Measures; Membrane Potentials; Metabolism; Mitochondria; Molecular; Mus; Myocardial; Myocardial Ischemia; Myosin Light Chains; Neonatal; Nucleotides; Pattern; Perinatal; Phenotype; Physiological; Play; Potassium; Potassium Channel; Property; Protein Isoforms; Proteins; RNA Splicing; Regulation; Reporter; Resistance; Role; Smooth Muscle Myocytes; Spasm; Staging; Stress; Sulfonylurea Compounds; Testing; Transgenes; Transmembrane Domain; Variant; Vasospasm; Ventricular; Work; biological adaptation to stress; functional restoration; improved; inward rectifier potassium channel; mRNA Expression; member; mitochondrial K(ATP) channel; mitochondrial dysfunction; mitochondrial membrane; nucleotide binding fold; protein complex; response; restoration; sudden cardiac death; sulfonylurea receptor; voltage clamp

DESCRIPTION (provided by applicant): ATP-sensitive potassium (KATP) channels play a critical role in many cellular stress responses by linking cellular metabolism and membrane potential. KATP channels are also the target of sulfonylurea drugs used to treat diabetes. The sulfonylurea receptor 2 (SUR2) is the regulatory subunit of cardiac KATP channel and directly binds to ADP. Therefore, the energy state of the cell determines channel opening. KATP channels are also present in mitochondria, but the molecular components of the mitochondrial channels are less clear. The major goal of the proposal is to determine the role of SUR2 in cardiac KATP cannels. Our laboratory's previous results show that mice lacking exons 14 to 18 (Ex14/18) of the SUR2 gene display vasospasm, arrhythmia, and sudden cardiac death. Surprisingly, the myocardial ischemic stress response was not attenuated in Ex14/18 mice. The discovery of shorter proteins related to SUR2 and produced from the same gene has suggested that these SUR2 short forms may confer ischemic resistance independent of canonical KATP channels. These SUR2 short forms were unperturbed in the Ex14/18 mouse. To explore this hypothesis, a new mouse was generated where exon 5 was deleted from the SUR gene. Exon 5 encodes a region critical for the translocation of both full and short SUR2 isoforms from the endoplasmic reticulum. While Ex14/18 mice survive until adulthood, Ex5 mice exhibit progressive cardiac dysfunction and die within 10 days of birth. I hypothesize that the Ex5 deletion affects both full length and short SUR2 forms. In AIM 1, I will study the developmental expression patterns of SUR2 short forms in normal, Ex14/18, and Ex5 hearts. In AIM 2, I will determine how of the SUR2 short forms contribute the KATP function by examining how SUR2 and the KATP potassium channel subunit, Kir6.2 interact and localize. In AIM 3, I will determine whether cardiac-specific expression of full length SUR2 is able to rescue the severe phenotype of Ex5 mice. The work from this proposal will shed light on the role of KATP channels in development and cardiac stress.

描述（由申请人提供）：ATP 敏感钾 (KATP) 通道通过连接细胞代谢和膜电位，在许多细胞应激反应中发挥关键作用。 KATP 通道也是用于治疗糖尿病的磺酰脲类药物的靶标。磺酰脲受体 2 (SUR2) 是心脏 KATP 通道的调节亚基，直接与 ADP 结合。因此，细胞的能量状态决定了通道的开放。 KATP 通道也存在于线粒体中，但线粒体通道的分子组成尚不清楚。该提案的主要目标是确定 SUR2 在心脏 KATP 通道中的作用。我们实验室之前的结果表明，缺乏SUR2基因14至18号外显子（Ex14/18）的小鼠会出现血管痉挛、心律失常和心源性猝死。令人惊讶的是，Ex14/18 小鼠的心肌缺血应激反应并未减弱。与 SUR2 相关并由同一基因产生的较短蛋白质的发现表明，这些 SUR2 短形式可能具有独立于经典 KATP 通道的缺血抵抗能力。这些 SUR2 短形式在 Ex14/18 小鼠中未受到干扰。为了探索这一假设，我们培育了一只新小鼠，其中 SUR 基因的外显子 5 被删除。外显子 5 编码一个对于完整和短 SUR2 亚型从内质网易位的关键区域。 Ex14/18 小鼠可以存活到成年，而 Ex5 小鼠则表现出进行性心脏功能障碍，并在出生后 10 天内死亡。我假设 Ex5 缺失同时影响全长和短 SUR2 形式。在 AIM 1 中，我将研究正常、Ex14/18 和 Ex5 心脏中 SUR2 短形式的发育表达模式。在 AIM 2 中，我将通过检查 SUR2 和 KATP 钾通道亚基 Kir6.2 如何相互作用和定位来确定 SUR2 短形式如何贡献 KATP 功能。在 AIM 3 中，我将确定全长 SUR2 的心脏特异性表达是否能够挽救 Ex5 小鼠的严重表型。该提案的工作将阐明 KATP 通道在发育和心脏应激中的作用。