Drp1 controls Complex II assembly and skeletal muscle metabolism by Sdhaf2 action on mitochondria

The Dynamin-related GTPase, Drp1 (encoded by Dnm1l) plays a central role in mitochondrial fission and is requisite for numerous cellular processes however its role in muscle metabolism remains unclear. Herein, we show that among human tissues, the highest number of gene correlations with DNM1L  are in skeletal muscle. Knockdown of Drp1 (Drp1-KD) promoted mitochondrial hyperfusion in the muscle of male mice. Reduced fatty acid oxidation and impaired insulin action along with increased muscle succinate was observed in Drp1-KD muscle. Muscle Drp1-KD reduced Complex II assembly and activity as a consequence of diminished mitochondrial translocation of succinate dehydrogenase assembly factor 2 (Sdhaf2). Restoration of Sdhaf2 normalized Complex II activity, lipid oxidation, and insulin action in Drp1-KD myocytes. Drp1 is critical in maintaining mitochondrial Complex II assembly, lipid oxidation, and insulin sensitivity, suggesting a mechanistic link between mitochondrial morphology and skelet..., RNAseq: A homogenous portion of frozen skeletal muscle samples was homogenized using a tissue homogenizer in Trizol. RNA was isolated using the Qiagen RNeasy Mini QIAcube Kit following the manufacturer’s instructions. Libraries were prepared using the TruSeq Stranded Total RNA Library Prep Kit and RiboZero Gold following the manufacturer’s instructions. The resulting libraries were combined into two pools and sequenced on an Illumina HiSeq 4000 within the UCLA Neuroscience Genomics core facility following in-house established protocols. For metabolomics, muscle samples were processed and analyzed by Metabolon Inc., , # Drp1 controls Complex II assembly and skeletal muscle metabolism by Sdhaf2 action on mitochondria

[https://doi.org/10.5061/dryad.wstqjq2sz](https://doi.org/10.5061/dryad.wstqjq2sz)

Table S4 contains the raw metabolomics data and Table S5 contains the raw RNA-sequencing data of gastrocnemius muscle from normal chow-fed male mDrp1HET vs. Control f/f mice.

## Description of the data and file structure

These data are in Excel files. Table S4 includes Biochemical, mouse ID, and Fold change. Table S5 includes gene ID, baseMean (the mean of normalized count of all samples), log2Foldchange, IfcSE (standard error of the log2FoldChange estimate), stat (statistics), pvalue (p value), and padj (adjusted p value).

动力相关GTP酶（Dynamin-related GTPase）Drp1（由Dnm1l基因编码）在线粒体裂变过程中发挥核心作用，且为诸多细胞进程所必需，但其在肌肉代谢中的作用仍有待阐明。本研究结果显示，在所有人体组织中，与DNM1L基因存在显著相关性的基因数量最多的组织为骨骼肌。敲低Drp1（Drp1-KD）可诱导雄性小鼠肌肉组织出现线粒体过度融合现象。在Drp1-KD小鼠的肌肉组织中，可观测到脂肪酸氧化水平下降、胰岛素介导的信号通路受损，同时肌肉内琥珀酸水平升高。肌肉组织中Drp1敲低会降低复合物II（Complex II）的组装效率与活性，其成因是琥珀酸脱氢酶组装因子2（succinate dehydrogenase assembly factor 2, Sdhaf2）的线粒体转位水平下降。恢复Sdhaf2的表达可使Drp1-KD肌细胞中的复合物II活性、脂质氧化水平与胰岛素介导的信号通路恢复至正常水平。Drp1对于维持线粒体复合物II组装、脂质氧化以及胰岛素敏感性至关重要，这表明线粒体形态与骨骼肌代谢之间存在机制层面的关联。

## RNA测序（RNA sequencing, RNAseq）：
将均一化的冰冻骨骼肌样本置于Trizol试剂中，使用组织匀浆器进行匀浆。随后按照制造商提供的操作说明，采用Qiagen RNeasy Mini QIAcube Kit分离总RNA。文库构建采用TruSeq Stranded Total RNA Library Prep Kit结合RiboZero Gold试剂，并严格遵循制造商提供的操作流程。将构建完成的文库合并为两个混合池，随后在加州大学洛杉矶分校（UCLA）神经基因组学核心实验室，按照内部建立的实验流程，在Illumina HiSeq 4000测序平台上完成测序。

代谢组学分析方面，肌肉样本的处理与检测由Metabolon Inc.公司完成。
# Drp1通过Sdhaf2作用于线粒体调控复合物II组装与骨骼肌代谢
https://doi.org/10.5061/dryad.wstqjq2sz

表S4包含原始代谢组学数据，表S5包含正常饮食喂养的雄性mDrp1HET小鼠与对照f/f小鼠腓肠肌的原始RNA测序数据。

## 数据与文件结构说明
这些数据存储于Excel文件中。表S4包含生化指标、小鼠编号与倍数变化值。表S5包含基因ID、baseMean（所有样本标准化计数的均值）、log2Foldchange、IfcSE（log2FoldChange估计值的标准误）、stat（统计量）、pvalue（p值）以及padj（校正后p值）。