下调心肌CPT1b的表达对肥胖小鼠心肌细胞钙调控的影响  

Effects of Cardiac-specific Carnitine Palmitoyltransferase-1b(CPT1b) Inhibition on Myocardial Calcium Handling

作　　者：张逸杰[1] 夏巍[1] 曹权[1] 戴明彦 何文博[1] 包明威[1] 

机构地区：[1]武汉大学人民医院心内科,武汉大学心血管病研究所,心血管病湖北省重点实验室,430060

出　　处：《医学研究杂志》2017年第5期22-27,158,共7页Journal of Medical Research

基　　金：国家自然科学基金资助项目(面上项目)(81570460);国家自然科学基金青年科学基金资助项目(81500668)

摘　　要：目的研究干扰心肌组织中肉毒碱脂酰转移酶-1b(CPT1b)的表达对高脂饮食诱导的肥胖小鼠心肌细胞钙调控的影响。方法 4周龄的雄性C57小鼠,随机分为正常对照组(N-mock)、肥胖对照组(O-mock)及肥胖干预组(O-CPT1b),采用高脂饮食诱导肥胖。6周龄时,经心肌分别注射靶向CPT1b(O-CPT1b)或靶向无关基因(N-mock、O-mock)的重组慢病毒,以下调目标基因的表达。10周后,取小鼠左心室组织检测RNA干扰的效率;采用Western blot法检测左心室组织中肌浆网钙泵(SERCA2a)的蛋白表达;并分离单个心室肌细胞,使用活细胞工作站检测心肌细胞钙瞬变。结果肥胖小鼠心肌组织中CPT1b的表达增加,慢病毒介导的RNA干扰显著下调其表达。肥胖引起心肌细胞SERCA2a的蛋白表达降低及肌质网钙处理能力的下降,下调CPT1b的表达增加了SERCA2a的含量,并改善了钙调控异常。结论下调心肌组织中CPT1b的表达可改善肥胖所导致的心肌细胞钙调控异常。Objective To study the effects of cardiac-specific CPT1b inhibition on myocardial calcium handling in high-fat-diet （HFD） induced obese mice. Methods Four-week-old male C57 mice were randomly divided into normal control group （N-mock）, obese control group （O-mock） and obese intervention group （O-CPT1b）. HFD was used to induce obesity in this study. At six weeks of age, mice were subjected to intramyocardial injection with recombinant lentivirus targeting murine CPT1b （for O-CPT1b） or irrelevant gene （for N-mock and O-mock） to down-regulate their expressions. Ten weeks later, left ventricular tissues were obtained. CPT1b mRNA and protein expressions were measured by RT-PCR and Western blot. The protein expression of sarco/endoplasmic reticulum Ca2＋-ATPase 2a （SERCA2a） was detected by Western blot. Isolated ventricular myocytes were obtained by enzymatic dissociation method, and used for myocardial calcium transient detection via live cell station. Results The mRNA and protein expressions of CPT1b were increased in obese mice hearts. Lentivirus-mediated RNAi significantly down-regulated cardiac CPT1b expression in O-CPT1b mice. Obesity decreased the protein expression of SERCA2a, and damaged calcium handling of sarcoplasmic reticulum as well. Cardiac CPT1b inhibition ameliorated the myocardial SERCA2a deficiency. Meanwhile, the calcium mishandling was improved in O-CPT1b mice hearts. Conclusion Cardiac-specific CPT1b suppression ameliorated myocardial calcium mishandling associated with obesity.

关 键 词：肥胖模型 CPT1b RNA干扰 钙调控异常 SERCA2A 

分 类 号：R541.8[医药卫生—心血管疾病]