LAMP-2B regulates human cardiomyocyte function by mediating autophagosome-lysosome fusion
LAMP-2B regulates human cardiomyocyte function by mediating autophagosome-lysosome fusion
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DOI：
10.1073/pnas.1808618116
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发表时间：
2019-01-08
影响因子：
11.1
通讯作者：
Song, Kunhua
中科院分区：
文献类型：
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作者：
Chi, Congwu;Leonard, Andrea;Song, Kunhua
溶酶体相关膜蛋白2(LAMP-2)基因突变与Danon病有关，Danon病通常通过不明确的机制导致心肌病/心力衰竭。在这里，我们确定LAMP-2亚型B(LAMP-2B)是人类心肌细胞(CMS)自噬小体-溶酶体融合所必需的。值得注意的是，LAMP-2B的功能独立于Synaxin 17(STX17)，后者是非CMS中自噬小体-溶酶体融合所必需的蛋白质。相反，LAMP-2B与自噬相关14(ATG14)和囊泡相关膜蛋白8(VAMP8)通过其C端螺旋卷曲结构域(CCD)相互作用，促进自噬融合。来自Danon患者的诱导多能干细胞(hiPSC-CMS)来源的CMS显示ATG14和VAMP8之间的共定位减少，自噬融合严重缺陷，以及线粒体和收缩异常。这种表型被非Danon HiPSC-CMS中的LAMP-2B基因敲除所概括。最后，LAMP-2突变的基因纠正挽救了Danon的表型。这些发现揭示了人类CMS中STX17非依赖的自噬融合机制，为解释Danon患者的心肌病提供了解释，并为靶向LAMP-2B介导的自噬来治疗这一患者群体奠定了基础。
Mutations in lysosomal-associated membrane protein 2 (LAMP-2) gene are associated with Danon disease, which often leads to cardiomyopathy/heart failure through poorly defined mechanisms. Here, we identify the LAMP-2 isoform B (LAMP-2B) as required for autophagosome-lysosome fusion in human cardiomyocytes (CMs). Remarkably, LAMP-2B functions independently of syntaxin 17 (STX17), a protein that is essential for autophagosome-lysosome fusion in non-CMs. Instead, LAMP-2B interacts with autophagy related 14 (ATG14) and vesicle-associated membrane protein 8 (VAMP8) through its C-terminal coiled coil domain (CCD) to promote autophagic fusion. CMs derived from induced pluripotent stem cells (hiPSC-CMs) from Danon patients exhibit decreased colocalization between ATG14 and VAMP8, profound defects in autophagic fusion, as well as mitochondrial and contractile abnormalities. This phenotype was recapitulated by LAMP-2B knockout in non-Danon hiPSC-CMs. Finally, gene correction of LAMP-2 mutation rescues the Danon phenotype. These findings reveal a STX17-independent autophagic fusion mechanism in human CMs, providing an explanation for cardiomyopathy in Danon patients and a foundation for targeting defective LAMP-2B-mediated autophagy to treat this patient population.