Deciphering the role of a novel micropeptide in cardiac function and dysfunction

破译新型微肽在心脏功能和功能障碍中的作用

• 批准号: 10331296
• 负责人: RHONDA BASSEL-DUBY
• 金额: $ 54.5万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-16 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10331296
• 关键词: Actomyosin; Affinity; Binding; Ca(2+)-Transporting ATPase; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cardiovascular Pathology; Cardiovascular Physiology; Cardiovascular system; Cell membrane; Cell physiology; Cultured Cells; Cytosol; Development; Dilated Cardiomyopathy; Disease; Dwarfism; Endothelium; Epithelial Cells; Family; Fostering; Functional disorder; Funding; Gene Delivery; Gene Transfer Techniques; Goals; Growth; Health; Heart; Heart Diseases; Heart failure; Homeostasis; Maintenance; Mediating; Membrane; Metabolic Diseases; Metabolism; Mission; Modeling; Mus; Muscle Cells; Muscle Contraction; Muscle relaxation phase; Myocardial dysfunction; Myopathy; Names; Open Reading Frames; Pathogenicity; Pathologic; Peptides; Play; Process; Protein Isoforms; Proteins; Public Health; Pump; RNA; RNA Sequences; Relaxation; Research; Role; Sarcomeres; Sarcoplasmic Reticulum; Second Messenger Systems; Signal Transduction; Signal Transduction Pathway; Stress; Striated Muscles; System; Testing; Therapeutic; Tissues; Transmembrane Domain; United States National Institutes of Health; Untranslated RNA; cell type; extracellular; genetic regulatory protein; heart function; in vivo; innovation; insight; loss of function; mouse model; novel; overexpression; phospholamban; prevent; protein protein interaction; response; reuptake; therapeutic target

Project Summary/Abstract Ca2+ controls cardiac function by acting as the primary regulator of the sarcomeric contractile machinery and as a second messenger in the signal transduction pathways that control cardiac growth, metabolism and pathological remodeling. Ca2+ handling in striated muscle is tightly regulated by Ca2+ pumps in the sarcoplasmic reticulum (SR) and plasma membranes that maintain intracellular Ca2+ levels ~10,000-fold lower than extracellular and SR concentrations. Ca2+ release from the SR membrane transiently increases Ca2+ levels in the cytosol, triggering actomyosin cross-bridge formation within the sarcomere to generate contractile force. Reuptake of Ca2+ into the SR by sarcoplasmic reticulum Ca2+-ATPase (SERCA) is necessary for muscle relaxation and restores SR Ca2+ levels for subsequent contraction-relaxation cycles. SERCA thus serves as a central regulator of cardiac function, as well as the pathogenic signaling cascades that drive heart disease. The activity of SERCA in the heart is modulated by phospholamban (PLN), a tiny peptide that interacts with SERCA in the SR membrane and diminishes Ca2+ pump activity. We discovered that a cardiac-specific RNA annotated as a long noncoding RNA actually encodes a previously unrecognized micropeptide, which we named DWORF (Dwarf Open Reading Frame). During the initial funding period we showed that DWORF has a higher binding affinity for SERCA than PLN and that DWORF overexpression mitigates the contractile dysfunction associated with PLN overexpression, substantiating its role as a potent activator of SERCA. Additionally, using a mouse model of dilated cardiomyopathy, we showed that DWORF overexpression restores cardiac function and prevents the pathological remodeling and Ca2+ dysregulation. Our results established DWORF as a potent activator of SERCA within the heart and as an attractive candidate for a heart failure therapeutic. Recently, we discovered two PLN-related micropeptides, referred to as Endoregulin (ELN) and Another-regulin (ALN), which associate with specific SERCA isoforms, suggesting their involvement in SERCA-dependent Ca2+ signaling. Collectively, we refer to this family of inhibitory SERCA micropeptides as Regulins. Our discovery of the DWORF- Regulin micropeptides provides new inroads into our understanding of the mechanisms involved in cardiac contractility and function and points to unexplored roles of micropeptides in the control of cardiovascular physiology and pathology. Our hypothesis is that DWORF-Regulin micropeptides are critical for cellular homeostasis and stress adaptation in disease, such that these micropeptides can serve as therapeutic targets for cardiovascular and metabolic diseases. The overall goals of this proposal are to define the functions and regulatory protein-protein interactions of DWORF and Regulins in the cardiovascular system and evaluate their therapeutic significance.

项目概要/摘要 Ca2+ 通过充当肌节收缩机制的主要调节器和作为 信号转导途径中的第二信使，控制心脏生长、代谢和 病理性重塑。横纹肌中的 Ca2+ 处理受到肌浆中 Ca2+ 泵的严格调节 维持细胞内 Ca2+ 水平约低于 10,000 倍的网织 (SR) 和质膜 细胞外浓度和 SR 浓度。 SR 膜释放的 Ca2+ 瞬时增加了体内 Ca2+ 水平 细胞质，触发肌节内肌动球蛋白跨桥形成，产生收缩力。 肌浆网 Ca2+-ATP 酶 (SERCA) 将 Ca2+ 重新摄取到 SR 中，对于肌肉来说是必需的 放松并恢复随后的收缩-放松周期的 SR Ca2+ 水平。 SERCA 因此充当 心脏功能的中央调节器，以及导致心脏病的致病信号级联。这 心脏中 SERCA 的活性受到受磷蛋白 (PLN) 的调节，PLN 是一种与 SERCA 相互作用的微小肽 SR 膜中并降低 Ca2+ 泵活性。我们发现心脏特异性 RNA 注释 因为长非编码RNA实际上编码了一种以前未被识别的微肽，我们将其命名为DWORF （矮人开放阅读框）。在最初的资助期间，我们证明了 DWORF 具有更高的结合力 对 SERCA 的亲和力高于 PLN，并且 DWORF 过度表达可减轻相关的收缩功能障碍 PLN 过度表达，证实了其作为 SERCA 有效激活剂的作用。另外，使用鼠标 在扩张型心肌病模型中，我们发现 DWORF 过度表达可恢复心脏功能，并且 防止病理重塑和 Ca2+ 失调。我们的结果表明 DWORF 是一种有效的 心脏内 SERCA 的激活剂，是心力衰竭治疗的有吸引力的候选者。最近，我们 发现了两种与 PLN 相关的微肽，称为 Endoregulin (ELN) 和 Another-regulin (ALN)， 与特定的 SERCA 同工型相关，表明它们参与 SERCA 依赖性 Ca2+ 信号传导。 总的来说，我们将这个抑制性 SERCA 微肽家族称为调节蛋白。我们对 DWORF 的发现- 调节蛋白微肽为我们理解心脏相关机制提供了新的进展 收缩性和功能，并指出微肽在心血管控制中尚未探索的作用 生理学和病理学。我们的假设是 DWORF-Regulin 微肽对细胞至关重要 疾病中的稳态和应激适应，因此这些微肽可以作为治疗靶点 用于心血管和代谢疾病。该提案的总体目标是定义职能和 DWORF 和 Regulins 在心血管系统中的调节蛋白-蛋白相互作用并评估其作用 治疗意义。