AAV-mediated transfer of FKRP shows therapeutic efficacy in a murine model but requires control of gene expression
AAV-mediated transfer of FKRP shows therapeutic efficacy in a murine model but requires control of gene expression
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DOI：
10.1093/hmg/ddx066
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发表时间：
2017-05-15
影响因子：
3.5
通讯作者：
Richard, Isabelle
中科院分区：
文献类型：
--
作者：
Gicquel, Evelyne;Maizonnier, Natacha;Richard, Isabelle
肢体带状肌营养不良症2I型（LGMD2I）是一种隐性常染色体肌营养不良症，由Fukutin相关蛋白（FKRP）基因突变引起。FKRP是一种利比醇-5-磷酸转移酶，它参与了α -糖醛酸失调（α DG）糖基化，这对确保肌纤维的细胞/基质锚定非常重要。生成LGMD2I敲入小鼠模型来表达患者中最常见的突变（L276I）。FKRP在转录和翻译水平上的表达均未发生改变，但由于观察到aDG异常糖基化，其功能受到影响。骨骼肌从2月龄开始功能受损，从6月龄开始出现明显的中度营养不良模式。用表达Fkrp的rAAV2/9载体进行基因转移，修复了小鼠模型的生化缺陷，纠正了组织学异常，提高了小鼠对偏心应激的抵抗力。然而，注射高剂量的载体诱导aDG糖基化和层粘连蛋白结合减少，即使在WT动物中也是如此。最后，将rAAV-Fkrp载体静脉注射到Fukutin （Fktn）敲除引起的糖代谢异常小鼠模型中，显示出剂量依赖性毒性。这些数据提示需要控制FKRP在肌肉中的表达。
Limb Girdle Muscular Dystrophies type 2I (LGMD2I), a recessive autosomal muscular dystrophy, is caused by mutations in the Fukutin Related Protein (FKRP) gene. It has been proposed that FKRP, a ribitol-5-phosphate transferase, is a participant in alpha-dystroglycan (alpha DG) glycosylation, which is important to ensure the cell/matrix anchor of muscle fibers. A LGMD2I knock-in mouse model was generated to express the most frequent mutation (L276I) encountered in patients. The expression of FKRP was not altered neither at transcriptional nor at translational levels, but its function was impacted since abnormal glycosylation of aDG was observed. Skeletal muscles were functionally impaired from 2 months of age and a moderate dystrophic pattern was evident starting from 6 months of age. Gene transfer with a rAAV2/9 vector expressing Fkrp restored biochemical defects, corrected the histological abnormalities and improved the resistance to eccentric stress in the mouse model. However, injection of high doses of the vector induced a decrease of aDG glycosylation and laminin binding, even in WT animals. Finally, intravenous injection of the rAAV-Fkrp vector into a dystroglycanopathy mouse model due to Fukutin (Fktn) knock-out indicated a dose-dependent toxicity. These data suggest requirement for a control of FKRP expression in muscles.