Deciphering a Novel LncRNA-mediated Lipid Droplet Transport System in Human Heart

破译人类心脏中新型 LncRNA 介导的脂滴转运系统

• 批准号: 10640148
• 负责人: Lei Yang
• 金额: $ 55.79万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10640148
• 关键词: 3-Dimensional; Adult; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cells; Cessation of life; Clustered Regularly Interspaced Short Palindromic Repeats; Cytoskeleton; Development; Diabetes Mellitus; Dimensions; Disease; Down-Regulation; Engineering; Fatty Acids; Functional disorder; Future; Genetic Transcription; Goals; Heart; Heart failure; High Fat Diet; Human; Impairment; In Vitro; Incidence; Knock-out; Laboratories; Lipid Binding; Lipids; Mediating; Membrane; Metabolic syndrome; Mitochondria; Mitochondrial Swelling; Modeling; Molecular; Mus; Mutation; Myocardial dysfunction; Myocardium; Nonmuscle Myosin Type IIB; Obesity; Patients; Pharmaceutical Preparations; Phenocopy; Phospholipids; Play; Proteins; RNA; Research; Rodent Model; Role; System; Testing; Tissues; Transgenes; Transgenic Mice; Transgenic Organisms; Type 2 diabetic; Untranslated RNA; cardiogenesis; cardioprotection; diabetic; diabetic cardiomyopathy; diabetic patient; feeding; heart function; heart preservation; human pluripotent stem cell; in vitro Model; in vivo; induced pluripotent stem cell; insight; lipid metabolism; long chain fatty acid; mitochondrial dysfunction; monolayer; non-muscle myosin; non-muscle myosin heavy chain-B; novel; overexpression; oxidation; translational potential

Abstract The overarching goal of this proposal is to uncover novel HUMAN-SPECIFIC molecular mechanisms by which human long non-coding RNA (lncRNA) HL6 facilitates lipid droplet (LD) transport in human cardiomyocytes (CMs) and manifests a cardioprotective role against metabolic syndrome associated cardiomyopathy. ~70% energy of adult human heart is obtained from oxidation of long chain fatty acids (FAs). Balanced lipid metabolism is crucial for heart function. Compromised lipid metabolism have been widely observed in cardiomyopathies associated with metabolic syndromes, such as obesity and diabetes. The distinct features of obese and diabetes associated cardiomyopathy are increased incidence of heart failure together with extensive intramyocyte lipid droplet accumulation. LD consists of a neutral lipid core surrounded by a phospholipid monolayer, which plays a critical role in excess fatty acid storage and mobilization. However, overwhelmed intramyocyte LDs can cause cardiac lipotoxicity and dysfunction in both human patients and rodent models of obesity and diabetes. Although ample evidence suggests that LD accumulation in CMs could be due to impaired LD transport, the cellular system for LD transport in mammalian heart remains elusive. Particularly, the human-specific LD transport system of CMs and its implication in metabolic syndrome associated cardiomyopathy and heart failure remain unknown. Recently, we identified a human lncRNA, Heart LncRNA 6 (HL6), which is highly and specifically expressed in human CMs and downregulated in human type 2 diabetic myocardium. HL6 was knocked out (HL6KO) in human iPSCs (hiPSCs) by using CRISPR/Cas-9. We found HL6 deficiency led to extensive LD accumulation, defective LD transport to mitochondria, swollen mitochondria with impaired function, and enhanced CM death in HL6KO hiPSC-CMs verse WT hiPSC-CMs. Intriguingly, HL6 binds LDs and cytoskeleton in hiPSC-CMs. Additionally, transgenic HL6 overexpression significantly mitigated high fat diet (HFD)-induced lipid accumulation and cardiac dysfunction of mouse heart. Therefore, we hypothesize that HL6 plays an indispensable role in LD transport to mitochondria in human CMs, and gain-of-HL6 manifests a cardioprotective role against metabolic syndrome associated cardiomyopathy. Two specific aims are proposed: Specific Aim 1: Decipher the indispensable role of HL6 in lipid droplet transport of human CMs. Specific Aim 2: Determine the cardioprotective role of HL6 in metabolic syndrome associated cardiomyopathy.

摘要 这项提议的首要目标是揭示新的人类特有的分子机制，通过 人长非编码RNA(LncRNA)HL6促进人心肌细胞脂滴(LD)转运 对代谢综合征相关性心肌病具有心脏保护作用。~70%的能源 成人心脏是由长链脂肪酸(FAs)氧化而成。平衡的脂类代谢至关重要 对心脏功能的影响。广泛观察到与心肌病相关的脂代谢受损 患有代谢综合征，如肥胖和糖尿病。与肥胖和糖尿病相关的明显特征 心肌病是心力衰竭发生率增加，并伴有广泛的心肌细胞内脂滴 积累。LD由一个被磷脂单分子层包围的中性脂核组成，它起着关键的作用 在过量的脂肪酸储存和动员中的作用。然而，超负荷的心肌细胞内LDS可导致心脏 肥胖和糖尿病的人类患者和啮齿动物模型中的脂毒性和功能障碍。虽然很充足 有证据表明，CMS中LD的积累可能是由于LD运输受损所致，细胞系统 乳酸在哺乳动物心脏中的转运仍然难以捉摸。特别是，CMS的人类特有的LD运输系统 它在代谢综合征相关的心肌病和心力衰竭中的作用尚不清楚。 最近，我们发现了一个人类LncRNA，心脏LncRNA6(HL6)，它在 人CMS，在人2型糖尿病心肌中表达下调。HL6(HL6KO)在 人IPSCs(HiPSCs)，使用CRISPR/Cas-9。我们发现HL6缺乏导致广泛的学习障碍 积聚，LD转运到线粒体的缺陷，线粒体肿胀并功能受损，以及 HL6KO HiPSC-CMS与WT HiPSC-CMS的CM死亡增强。耐人寻味的是，HL6与LD和 HIPSC-CMS中的细胞骨架。此外，转基因HL6的过度表达显著缓解了高脂肪饮食 高脂蛋白(HFD)诱导的小鼠心脏脂质蓄积和心功能不全。因此，我们假设HL6 在人类CMS中LD转运到线粒体中起着不可或缺的作用，而Gain-of-HL6表现为 对代谢综合征相关性心肌病的心脏保护作用。提出了两个具体目标： 具体目的1：破译HL6在人类CMS脂滴运输中不可或缺的作用。具体目标2： 确定HL6在代谢综合征相关性心肌病中的心肌保护作用。