Ceramide-Induced Destruction in Emphysema

摘要 肺气肿的一个标志是形成气体交换所需的肺泡单位的细胞的净损失，这是由于 增加的损伤和受损的细胞修复所造成的吸入香烟烟雾（CS）。我们的建议将 重点是如何提高肺微血管内皮细胞的存活和修复，这是必不可少的， 维持肺泡毛细血管膜。为了在压力下存活下来，受损的细胞会进行修复， 自噬，其特征是一系列致力于受损细胞的溶酶体降解的步骤（通量） 蛋白质和细胞器。尽管在将自噬与COPD联系起来方面取得了进展，但很少有人知道CS是如何发生的。 破坏了自噬流，并且缺乏恢复其正常功能的方法。我们建议填补这个 通过阐明鞘脂对溶酶体适应性和自噬通量的调节， 代谢物在体内平衡和CS暴露期间。我们发现了两种鞘脂变阻器（鞘氨醇/S1 P 和神经酰胺/葡糖神经酰胺），其控制自噬通量，但被CS干扰。我们假设 鞘脂变阻器的恢复是完成溶酶体自噬和修复香烟所必需的 吸烟引起的肺微血管内皮细胞损伤，并会减轻肺气肿。我们将使用 人肺原代内皮细胞在2D和3D修复模型中的互补方法，包括 与肺泡II型上皮细胞、人精确切割的肺切片和CS小鼠模型共培养 为了实现三个具体目标，这些目标的完成将填补重要的知识空白， 肺气肿的发病机制，将机械地联系有针对性的代谢组学与功能结果， 为肺气肿的治疗提供了潜在的新靶点。

Abstract A hallmark of emphysema is the net loss of cells that form alveolar units required for gas exchange, due to increased injury and impaired cell repair caused by inhalation of cigarette smoking (CS). Our proposal will focus on how to enhance the survival and repair of lung microvascular endothelial cells, which are essential for the maintenance of the alveolo-capillary membrane. To survive stress, injured cells engage a repair process, autophagy, characterized by a sequence of steps (flux) devoted to the lysosomal degradation of damaged proteins and organelles. Despite progress made in linking autophagy with COPD, little is known as to how CS disrupts autophagic flux and approaches to restore its proper function are lacking. We propose to fill this knowledge gap, by elucidating the regulation of lysosomal fitness and autophagic flux by sphingolipid metabolites during homeostasis and CS exposure. We uncovered two sphingolipid rheostats (sphingosine/S1P and ceramide/glucosylceramide) that control the autophagy flux, but are disturbed by CS. We hypothesize that restoration of the sphingolipid rheostat is required to complete lysosomal autophagy and repair cigarette smoke-induced lung microvascular endothelial cell injury and will alleviate emphysema. We will use complementary approaches of human lung primary endothelial cells in 2D and 3D models of repair, including co-cultured with alveolar type II epithelial cells, human precision cut lung slices, and mouse models of CS exposure, to pursue three specific aims. Completion of these aims will fill important knowledge gaps in emphysema pathogenesis, will mechanistically link targeted metabolomics with functional outcomes, and provide potential new targets for treatment of emphysema.