ANO5 in Muscle Health and Disease

项目概要 ANO5 突变与包括肌营养不良症在内的多种人类疾病有关。 Ano5 是一个 细胞内膜蛋白，属于 anoctamin 蛋白家族。这个家族的许多蛋白质 已发现具有 Ca2 激活的磷脂加扰活性。尽管有明确的遗传 ANO5 与患者肌营养不良症之间的联系，我们发现小鼠体内 Ano5 完全敲除 在我们最后的资助期间没有表现出明显的肌肉病理学。这已得到其他人的独立证实 研究人员使用不同品系的完整 Ano5-KO 小鼠。这些发现表明，潜在的 补偿机制，可能是通过其他 anoctamin 蛋白，参与最大限度地减少 Ano5 完全缺乏。有趣的是，Ano5-KO 小鼠可能表达截短的 Ano5 肽 出现肌营养不良症的临床症状，伴有细胞内聚集和膜修复缺陷。 许多与人类肌营养不良症相关的 ANO5 突变都是过早终止突变。 这些发现提出了一个有趣的问题：ANO5 突变如何导致人类肌肉退化 患者：突变氨基末端Ano5肽的表达是否通过促进肌营养不良症 细胞内聚集体的形成和损害膜修复机制？我们的持续 本提案的研究重点是确定 Ano5 氨基末端在 调节 anoctamins 蛋白的内在脂质扰乱功能、膜修复及其对 ANO5突变引起的肌营养不良症的发病机制。此外，我们的研究将揭示 完全 Ano5-KO 小鼠缺乏肌营养不良表型的补偿机制。 通过使用体内 CRISPR 基因编辑、生化、组织病理学和活细胞成像研究 通过动物模型，我们计划的实验将增进我们对生理和 氨基末端 Ano5 肽在肌肉中的病理作用，并对 开发治疗 Ano5 相关肌营养不良症的新治疗策略。

PROJECT SUMMARY Mutations in ANO5 have been linked to several human diseases including muscular dystrophy. Ano5 is an intracellular membrane protein, belonging to the anoctamin protein family. Many of the proteins in this family have been found to possess the Ca2+-activated phospholipid scrambling activity. Despite the clear genetic linkage between ANO5 and muscular dystrophy in patients, we found that complete KO of Ano5 in mice showed no overt muscle pathology during our last funding period. This was independently confirmed by other investigators using a different line of complete Ano5-KO mice. These findings indicate that a potential compensatory mechanism, likely through other anoctamin proteins, is involved in minimizing the impact of complete Ano5 deficiency. Intriguingly, an Ano5-KO mouse expressing putatively a truncated Ano5 peptide developed clinical signs of muscular dystrophy with intracellular aggregates and defective membrane repair. Many of the ANO5 mutations associated with human muscular dystrophy are premature termination mutations. These findings raise an interesting question about how ANO5 mutations cause muscle degeneration in human patients: does the expression of mutant amino-terminal Ano5 peptide lead to muscular dystrophy by promoting the formation of intracellular aggregates and compromising membrane repair machinery? Our continuing research in this proposal is centered on determining the fundamental role of the amino-terminus of Ano5 in regulating the intrinsic lipid scrambling function of anoctamins proteins, membrane repair and its contribution to the pathogenesis of muscular dystrophy caused by ANO5 mutations. Moreover, our studies will reveal the compensatory mechanism underlying the lack of muscular dystrophy phenotype in complete Ano5-KO mice. Through the use of in vivo CRISPR gene editing, biochemical, histopathological, and living cell imaging studies with animal models, our planned experiments shall advance our understanding of the physiological and pathological roles of amino-terminal Ano5 peptides in muscle and also shed critical insights into the development of novel therapeutic strategies for the treatment of Ano5-related muscular dystrophy.