RYR1 encodes the type 1 ryanodine receptor, an intracellular calcium release channel (RyR1) on the skeletal muscle sarcoplasmic reticulum (SR). Pathogenic RYR1 variations can destabilize RyR1 leading to calcium leak causing oxidative overload and myopathy. However, the effect of RyR1 leak has not been established in individuals with RYR1-related myopathies (RYR1-RM), a broad spectrum of rare neuromuscular disorders. We sought to determine whether RYR1-RM affected individuals exhibit pathologic, leaky RyR1 and whether variant location in the channel structure can predict pathogenicity. Skeletal muscle biopsies were obtained from 17 individuals with RYR1-RM. Mutant RyR1 from these individuals exhibited pathologic SR calcium leak and increased activity of calcium-activated proteases. The increased calcium leak and protease activity were normalized by ex-vivo treatment with S107, a RyR stabilizing Rycal molecule. Using the cryo-EM structure of RyR1 and a new dataset of > 2200 suspected RYR1-RM affected individuals we developed a method for assigning pathogenicity probabilities to RYR1 variants based on 3D co-localization of known pathogenic variants. This study provides the rationale for a clinical trial testing Rycals in RYR1-RM affected individuals and introduces a predictive tool for investigating the pathogenicity of RYR1 variants of uncertain significance.

中文翻译：

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细胞内钙泄漏作为RYR1相关性肌病的治疗靶标。

RYR1编码1型ryanodine受体，即骨骼肌肌质网（SR）上的细胞内钙释放通道（RyR1）。致病性RYR1变异可破坏RyR1的稳定性，导致钙泄漏，从而导致氧化超负荷和肌病。但是，尚未在患有RYR1相关性肌病（RYR1-RM）（广泛的罕见神经肌肉疾病）的个体中建立RyR1泄漏的作用。我们试图确定受RYR1-RM影响的个体是否表现出病理性，漏泄的RyR1，以及通道结构中的变异位置是否可以预测致病性。从RYR1-RM的17位个体获得骨骼肌活检。这些个体的突变RyR1表现出病理性SR钙泄漏和钙激活蛋白酶活性增加。通过用RyR稳定Rycal分子S107进行离体处理，可以使增加的钙泄漏和蛋白酶活性标准化。使用RyR1的冷冻电磁结构和新的数据集，该数据集包含2200多例受RYR1-RM影响的可疑个体，我们开发了一种基于已知病原变体的3D共定位为RYR1变体分配致病性概率的方法。这项研究为在RYR1-RM患病个体中进行Rycals的临床试验提供了理论依据，并为研究不确定意义的RYR1变体的致病性提供了一种预测工具。2200名受RYR1-RM影响的可疑个体，我们开发了一种基于已知致病变体的3D共定位为RYR1变体分配致病性概率的方法。这项研究为在RYR1-RM患病个体中进行Rycals的临床试验提供了理论依据，并为研究不确定意义的RYR1变体的致病性提供了一种预测工具。2200名受RYR1-RM影响的可疑个体，我们开发了一种基于已知病原体变异体的3D共定位为RYR1变异体分配致病性概率的方法。这项研究为在RYR1-RM患病个体中进行Rycals的临床试验提供了理论依据，并为研究不确定意义的RYR1变体的致病性提供了一种预测工具。