SWELL1-LRRC8 mediated regulation of skeletal muscle function and metabolism

项目摘要 众所周知，保持肌肉质量有利于预防肥胖和肥胖相关疾病 例如糖尿病和心脏病，以及促进本港人口老化的整体健康。骨骼 肌肉萎缩与癌症（恶病质）、心力衰竭、慢性皮质类固醇使用、瘫痪或 失神经支配（废用性萎缩）、衰老、导致代谢健康不良和死亡率增加。因此，委员会认为， 更深入地了解调节骨骼肌维持，生长和 功能对人类健康至关重要。 我们最近发现，在骨骼肌中，SWELL 1是维持AKT-mTOR信号传导所必需的， 肌肉纤维大小，运动能力，力量产生，肥胖和全身性肥胖，从而揭示了一种新的 SWELL 1-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，SWELL 1通道 复合物也在溶酶体中表达和发挥功能（Lyso-SWELL 1）-这一观点也得到了支持 通过最近的无偏CRISPR筛选。鉴于溶酶体是整合营养感知的信号中枢 和AKT-mTOR信号转导，我们假设SWELL 1-LRRC 8通道共调节质膜 PI 3 K-AKT信号传导和以溶酶体为中心的营养素-mTOR信号传导。为了验证这个假设，我们将联合收割机 我们在SWELL 1信号传导方面的独特试剂和专业知识与Diwan（溶酶体信号传导），Xu （溶酶体膜片钳）和Meyer（骨骼肌生理学）实验室。我们的目标是了解 质膜SWELL 1信号传导和溶酶体SWELL 1（Lyso-SWELL 1）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。这些理由 研究表明，描述骨骼肌SWELL 1-AKT-mTOR信号传导的分子机制将 推进我们对新的，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： · AIM#1：描述质膜相对于溶酶体SWELL 1信号传导至AKT的机制。 骨骼肌细胞中的mTOR信号传导。这些研究将测试细胞营养感测的新范式 通过体外溶酶体离子通道信号复合物，为体内实验奠定基础。 · AIM#2：检查SWELL 1信号传导对有氧能力、骨骼肌生长和肌肉生长的贡献。 通过训练和老化在体内产生力。这些研究将确定SWELL 1的贡献 信号传导到骨骼肌生长和体内信号传导，以及衰老。

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 Furthermore, our group now has published and unpublished biochemical, patch-clamp and imaging evidence that SWELL1 channel complexes are also expressed and functional in lysosomes (Lyso-SWELL1) – a notion also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.