SNX14 deficiency-induced defective axonal mitochondrial transport in Purkinje cells underlies cerebellar ataxia and can be reversed by valproate.

Loss-of-function mutations in sorting nexin 14 (SNX14) cause autosomal recessive spinocerebellar ataxia 20, which is a form of early-onset cerebellar ataxia that lacks molecular mechanisms and mouse models. We generated Snx14-deficient mouse models and observed severe motor deficits and cell-autonomous Purkinje cell degeneration. SNX14 deficiency disrupted microtubule organization and mitochondrial transport in axons by destabilizing the microtubule-severing enzyme spastin, which is implicated in dominant hereditary spastic paraplegia with cerebellar ataxia, and compromised axonal integrity and mitochondrial function. Axonal transport disruption and mitochondrial dysfunction further led to degeneration of high-energy-demanding Purkinje cells, which resulted in the pathogenesis of cerebellar ataxia. The antiepileptic drug valproate ameliorated motor deficits and cerebellar degeneration in Snx14-deficient mice via the restoration of mitochondrial transport and function in Purkinje cells. Our study revealed an unprecedented role for SNX14-dependent axonal transport in cerebellar ataxia, demonstrated the convergence of SNX14 and spastin in mitochondrial dysfunction, and suggested valproate as a potential therapeutic agent. © The Author(s) 2021. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.

Citation

Hongfeng Zhang, Yujuan Hong, Weijie Yang, Ruimin Wang, Ting Yao, Jian Wang, Ke Liu, Huilong Yuan, Chaoqun Xu, Yuanyuan Zhou, Guanxian Li, Lishan Zhang, Hong Luo, Xian Zhang, Dan Du, Hao Sun, Qiuyang Zheng, Yun-Wu Zhang, Yingjun Zhao, Ying Zhou, Huaxi Xu, Xin Wang. SNX14 deficiency-induced defective axonal mitochondrial transport in Purkinje cells underlies cerebellar ataxia and can be reversed by valproate. National science review. 2021 Jul;8(7):nwab024

PMID: 34691693

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