Myofibroblasts are key cellular effectors of corneal wound healing from trauma, surgery, or infection. However, their persistent deposition of disorganized extracellular matrix can also cause corneal fibrosis and visual impairment. Recent work showed that the PPARγ agonist Troglitazone can mitigate established corneal fibrosis, and parallel in vitro data suggested this occurred through inhibition of the mitochondrial pyruvate carrier (MPC) rather than PPARγ. In addition to oxidative phosphorylation (Ox-Phos), pyruvate and other mitochondrial metabolites provide carbon for the synthesis of biological macromolecules. However, it is currently unclear how these roles selectively impact fibrosis. Here, we performed bioenergetic, metabolomic, and epigenetic analyses of corneal fibroblasts treated with TGF-β1 to stimulate myofibroblast -differentiation, with further addition of Troglitazone or the MPC inhibitor UK5099, to identify MPC-dependencies that may facilitate remodeling and loss of the myofibroblast phenotype. Our results show that a shift in energy metabolism is associated with, but not sufficient to drive cellular remodeling. Metabolites whose abundances were sensitive to MPC inhibition suggest that sustained carbon influx into the Krebs’ cycle is prioritized over proline synthesis to fuel collagen deposition. Furthermore, increased abundance of acetyl-CoA and increased histone H3 acetylation suggest that epigenetic mechanisms downstream of metabolic remodeling may reinforce cellular phenotypes. Overall, our results highlight a novel molecular target and metabolic vulnerability that affects myofibroblast persistence in the context of corneal wounding.

中文翻译：

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操纵线粒体丙酮酸载体功能导致角膜肌成纤维细胞代谢重塑，从而改善纤维化


肌成纤维细胞是创伤、手术或感染引起的角膜伤口愈合的关键细胞效应器。然而，它们持续沉积的杂乱的细胞外基质也会导致角膜纤维化和视力障碍。最近的研究表明，PPARγ 激动剂曲格列酮可以减轻已形成的角膜纤维化，并且平行的体外数据表明，这是通过抑制线粒体丙酮酸载体 (MPC) 而不是 PPARγ 来实现的。除了氧化磷酸化（Ox-Phos）之外，丙酮酸和其他线粒体代谢物还为生物大分子的合成提供碳。然而，目前尚不清楚这些作用如何选择性地影响纤维化。在这里，我们对用 TGF-β1 处理的角膜成纤维细胞进行生物能、代谢组学和表观遗传学分析，以刺激肌成纤维细胞分化，并进一步添加曲格列酮或 MPC 抑制剂 UK5099，以确定可能促进肌成纤维细胞重塑和丧失的 MPC 依赖性表型。我们的结果表明，能量代谢的转变与细胞重塑相关，但不足以驱动细胞重塑。丰度对 MPC 抑制敏感的代谢物表明，持续碳流入克雷布斯循环优先于脯氨酸合成，以促进胶原蛋白沉积。此外，乙酰辅酶A丰度的增加和组蛋白H3乙酰化的增加表明代谢重塑下游的表观遗传机制可能会增强细胞表型。总的来说，我们的结果强调了一个新的分子靶点和代谢脆弱性，在角膜受伤的情况下影响肌成纤维细胞的持久性。