ANO5 in Muscle Health and Disease

项目总结 ANO5的突变被认为与包括肌肉营养不良在内的几种人类疾病有关。Ano5是一种 胞内膜蛋白，属于异辛胺蛋白家族。这个家族中的许多蛋白质 已发现具有钙激活的磷脂争抢活性。尽管有明确的基因 ANO5与肌营养不良患者的联系，我们在小鼠中发现了ANO5的完整KO 在我们的上一次资助期间没有明显的肌肉病变。这一点得到了其他人的独立证实 研究人员使用了不同品系的完整Ano5-KO小鼠。这些发现表明，一个潜在的 代偿机制，可能通过其他ANoctamin蛋白，参与最小化的影响 Ano5完全缺乏症。有趣的是，一只Ano5-KO小鼠可能表达了一种截短的Ano5肽 出现肌营养不良症的临床症状，伴有细胞内聚集体和膜修复缺陷。 许多与人类肌肉营养不良相关的ANO5突变是过早终止突变。 这些发现提出了一个有趣的问题，即ANO5突变是如何导致人类肌肉退化的 患者：突变氨基末端Ano5肽的表达是否通过促进肌肉营养不良 细胞内聚集体的形成和膜修复机制的破坏？我们的继续 这项建议的研究集中在确定ANO5的氨基末端在 调节AnocTamins蛋白固有的脂质扰乱功能、膜修复及其在 ANO5基因突变引起的肌营养不良的发病机制。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代偿机制。 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，我们计划的实验将促进我们对生理和 氨基末端Ano5肽在肌肉中的病理作用 开发治疗ANO5相关性肌营养不良的新治疗策略。

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.