Translocation of TRPV4-PI3Kγ complexes to the plasma membrane drives myofibroblast transdifferentiation
Translocation of TRPV4-PI3Kγ complexes to the plasma membrane drives myofibroblast transdifferentiation
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DOI：
10.1126/scisignal.aau1533
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发表时间：
2019-11-12
影响因子：
7.3
通讯作者：
Olman, Mitchell A.
中科院分区：
文献类型：
--
作者：
Grove, Lisa M.;Mohan, Maradumane L.;Olman, Mitchell A.
肌成纤维细胞是几个主要器官的病理性纤维化状况的关键贡献者。成纤维细胞转分化成肌成纤维细胞需要机械信号和转化生长因子-β（TGF-β）信号传导。阳离子通道瞬时受体电位香草酸4（TRPV 4）通过其对细胞外基质硬度的机械敏感性而成为肌成纤维细胞转分化和体内纤维化的关键介质。在这里，我们发现TRPV 4通过与磷酸肌醇3-激酶γ（PI 3 K γ）相互作用，形成纳摩尔亲和力的细胞内TRPV 4-PI 3 K γ复合物，促进人和小鼠肺成纤维细胞的转分化。TGF-β诱导TRPV 4-PI 3 K γ复合物向质膜的募集，并增加TRPV 4和PI 3 K γ的活性。使用获得和丧失功能的方法，我们表明，TRPV 4和PI 3 K γ所需的肌成纤维细胞转分化的增加生产的α-平滑肌肌动蛋白和其纳入应力纤维，细胞骨架的变化，胶原蛋白-1的生产，和收缩力的评估。在缺乏PI 3 K γ的细胞中表达PI 3 K γ催化亚基（p110 γ）的各种突变形式表明，只有p110 γ的非催化氨基末端结构域对于TGF-β诱导的TRPV 4质膜募集和肌成纤维细胞转分化是必要和足够的。这些数据表明，TGF-β刺激PI 3 K γ的非经典支架作用，其将TRPV 4-PI 3 K γ复合物募集到质膜，从而增加肌成纤维细胞转分化。鉴于TRPV 4和PI 3 K γ两者都具有多效性作用，靶向它们之间的相互作用可以提供用于抑制肌成纤维细胞转分化的特异性治疗方法。
Myofibroblasts are key contributors to pathological fibrotic conditions of several major organs. The transdifferentiation of fibroblasts into myofibroblasts requires both a mechanical signal and transforming growth factor-beta (TGF-beta) signaling. The cation channel transient receptor potential vanilloid 4 (TRPV4) is a critical mediator of myofibroblast transdifferentiation and in vivo fibrosis through its mechanosensitivity to extracellular matrix stiffness. Here, we showed that TRPV4 promoted the transdifferentiation of human and mouse lung fibroblasts through its interaction with phosphoinositide 3-kinase gamma (PI3K gamma), forming nanomolar-affinity, intracellular TRPV4-PI3K gamma complexes. TGF-beta induced the recruitment of TRPV4-PI3K gamma complexes to the plasma membrane and increased the activities of both TRPV4 and PI3K gamma. Using gain- and loss-of-function approaches, we showed that both TRPV4 and PI3K gamma were required for myofibroblast transdifferentiation as assessed by the increased production of alpha-smooth muscle actin and its incorporation into stress fibers, cytoskeletal changes, collagen-1 production, and contractile force. Expression of various mutant forms of the PI3K gamma catalytic subunit (p110 gamma) in cells lacking PI3K gamma revealed that only the noncatalytic, amino-terminal domain of p110 gamma was necessary and sufficient for TGF-beta-induced TRPV4 plasma membrane recruitment and myofibroblast transdifferentiation. These data suggest that TGF-beta stimulates a noncanonical scaffolding action of PI3K gamma, which recruits TRPV4-PI3K gamma complexes to the plasma membrane, thereby increasing myofibroblast transdifferentiation. Given that both TRPV4 and PI3K gamma have pleiotropic actions, targeting the interaction between them could provide a specific therapeutic approach for inhibiting myofibroblast transdifferentiation.