SWELL1-LRRC8 mediated regulation of skeletal muscle function and metabolism

项目摘要 众所周知，保持肌肉质量有助于预防肥胖和肥胖相关疾病。 例如糖尿病和心脏病，除了促进我们老龄化人口的整体健康外。骨骼 肌肉萎缩与癌症(恶病质)、心力衰竭、长期使用皮质类固醇、瘫痪或 去神经(废用性萎缩)，衰老，导致新陈代谢健康不良，并增加死亡率。因此， 对调节骨骼肌维持、生长和发育的分子机制有更深入的了解 人体机能对人体健康至关重要。 我们最近发现，在骨骼肌中，SWELL1是维持AKT-mTOR信号所必需的，正常 肌肉纤维大小、运动能力、力量生成、肥胖和全身性血糖，从而揭示了一种新的 SWELL1-AKT-mTOR信号轴在骨骼肌生理学中的作用。此外，我们集团现在有 已发表和未发表的生化、膜片钳和成像证据表明SWELL1通道 复合体也在溶酶体(lyso-SWELL1)中表达和发挥功能--这一概念也得到了支持 由最近不偏不倚的CRISPR屏幕。鉴于溶酶体是整合营养感知的信号中枢 和AKT-mTOR信号，我们假设SWELL1-LRRC8通道共同调节质膜 PI3K-AKT信号和溶酶体介导的营养mTOR信号。为了检验这一假设，我们结合了 我们在SWELL1信号转导方面的独特试剂和专业知识与Diwan(溶酶体信号转导)的试剂和专业知识相同 (溶酶体膜片钳)和迈耶(骨骼肌生理学)实验室。我们的目标是了解 质膜SWELL1信号和溶酶体SWELL1(lyso-SWELL1)营养的双重机制 骨骼肌的感觉及其对骨骼肌生长和功能的贡献。这样做的理由是 研究表明，阐明骨骼肌SWELL1-AKT-mTOR信号转导的分子机制将 促进我们对新的、基本的机械信号和营养传感机制的理解 调节骨骼肌的生长和功能。我们提出以下目标： ·目的1：阐明质膜与溶酶体SWELL1信号转导AKT-1的机制 骨骼肌细胞中的mTOR信号。这些研究将测试细胞营养传感的新范例。 在体外通过溶酶体离子通道信号复合体，为体内实验奠定了基础。 ·目的2：研究SWELL1信号对有氧能力、骨骼肌生长和 随着训练和衰老，在体内产生力量。这些研究将确定SWELL1的贡献 骨骼肌生长的信号和体内的信号，以及随着年龄的增长。

Project Summary Maintenance of muscle mass is known to be beneficial in the prevention of obesity and obesity-related diseases such as diabetes and heart disease, in addition to promoting overall health of our aging population. Skeletal muscle atrophy is associated with cancer (cachexia), heart failure, chronic corticosteroid use, paralysis or denervation (disuse atrophy), aging, contributing to poor metabolic health, and increased mortality. Accordingly, a deeper understanding of the molecular mechanisms that regulate skeletal muscle maintenance, growth and function is critical for human health. We recently showed that, in skeletal muscle, SWELL1 is required for maintaining AKT-mTOR signaling, normal muscle fiber size, exercise capacity, force generation, adiposity and systemic glycemia, thereby revealing a novel role for a SWELL1-AKT-mTOR signaling axis in skeletal muscle physiology. Furthermore, our group now has published and unpublished biochemical, patch-clamp and imaging evidence that SWELL1 channel complexes are also expressed and functional in lysosomes (Lyso-SWELL1) – a notion also supported by a recent unbiased CRISPR screen. Given that lysosomes are signaling hubs that integrate nutrient sensing and AKT-mTOR signaling, we hypothesize that SWELL1-LRRC8 channels co-regulate plasma membrane PI3K-AKT signaling and lysosome centered nutrient-mTOR signaling. To test this hypothesis, we combine our unique reagents and expertise in SWELL1 signaling with the those of the Diwan (lysosomal signaling), Xu (lysosomal patch-clamp), and Meyer (skeletal muscle physiology) laboratories. Our objective is to understand the dual mechanisms of plasma membrane SWELL1 signaling and lysosomal SWELL1 (Lyso-SWELL1) nutrient sensing in skeletal muscle and its contribution to skeletal muscle growth and function. The rationale for these studies is that delineating the molecular mechanisms of skeletal muscle SWELL1-AKT-mTOR signaling will advance our understanding of novel, fundamental mechano-signaling and nutrient sensing mechanisms that regulate skeletal muscle growth and function. We propose the following AIMs: · AIM#1: Delineate the mechanisms of plasma membrane versus lysosomal SWELL1 signaling to AKT- mTOR signaling in skeletal muscle cells. These studies will test a novel paradigm for cellular nutrient sensing by a lysosomal ion channel signaling complex in vitro, setting the stage for in vivo experiments. · AIM#2: Examine the contribution of SWELL1 signaling to aerobic capacity, skeletal muscle growth, and force generation in vivo with training and with aging. These studies will define the contributions of SWELL1 signaling to skeletal muscle growth and signaling in vivo, and with aging.