Novel mechanisms of regulating endoplasmic reticulum homeostasis in alcoholic pancreatitis

项目摘要 酗酒是引发人类和啮齿动物胰腺炎的主要危险因素。然而，只有不到 10%的酗酒者会患上酒精性胰腺炎，而大多数酗酒者会患上轻度自限性胰腺炎 病理变化，提示胰腺细胞的精细化适应，以保护其免受 酒精的影响。胰腺外分泌腺泡细胞具有很高的蛋白质合成率，可以产生和分泌 大量的消化酶。为了满足蛋白质合成的高要求，腺泡细胞 特别富含内质网(ER)。内质网稳态失调可导致内质网 应激和腺泡细胞损伤导致胰腺炎的发病。细胞使用保护机制，如 自噬来平衡内质网等细胞器的动态平衡，以适应和保护自己免受内质网的影响 压力。小鼠胰腺基础自噬缺陷破坏内质网稳态，导致内质网应激和 自发性胰腺炎。我们最近证实，转录因子EB(TFEB)直接调节 溶酶体的生物发生和间接的自噬，这是由酒精引起的酒精性肝炎和 胰腺炎。我们的初步研究表明，酒精喂养会降低VMP1(液泡膜蛋白 1)，一个内质网驻留的多跨膜蛋白，在mRNA和蛋白质水平上，在实验中 酒精性胰腺炎小鼠模型。更重要的是，小鼠腺泡细胞特异性缺失VMP1导致 内质网应激增加和自发性胰腺炎。受损和过剩的内质网可以通过选择性的 自噬，称为内质网吞噬，有助于维持内质网稳态，缓解内质网应激。我们的长- 这项提议的长期目标是了解酒精如何降低VMP1在脑内的分子机制。 腺泡细胞和VMP1介导的自噬如何预防酒精诱导的胰腺炎。的目标是 这项建议是为了了解VMP1介导的ER吞噬是如何被酒精破坏的腺泡细胞，以及如何 从药理上维持腺泡细胞内质网稳态，以预防酒精性胰腺炎。我们会 确定TFEB-VMP1介导的ER-噬菌体的遗传和药物激活如何调节ER 动态平衡和预防酒精引起的胰腺炎。这项提议将为 VMP1介导的酒精性胰腺炎治疗新疗法的研究进展 吞噬内质网以维持腺泡细胞细胞器的动态平衡。

Project Summary Alcohol abuse is a major risk factor in initiating pancreatitis in humans and in rodents. However, only less than 10% of heavy drinkers develop alcoholic pancreatitis whereas most heavy drinkers have mild and autolimited pathological changes, suggesting that a refined adaptation in pancreatic cells to protect against the detrimental effects of alcohol. Pancreatic exocrine acinar cells possess high protein synthetic rates to produce and secrete large amounts of digestive enzymes. To meet the high demand of protein synthesis, acinar cells are exceptionally enriched with endoplasmic reticulum (ER). Dysregulation of ER homeostasis can lead to ER stress and acinar cell damage resulting in the onset of pancreatitis. Cells use protective mechanisms such as autophagy to balance the homeostasis of organelles such as ER to adapt and protect themselves from ER stress. Defective basal autophagy in mouse pancreas disrupts ER homoeostasis resulting in ER stress and spontaneous pancreatitis. We recently demonstrated that transcription factor EB (TFEB) directly regulates lysosomal biogenesis and, indirectly, autophagy, which is impaired by alcohol causing alcoholic hepatitis and pancreatitis. Our preliminary studies showed that alcohol feeding decreased VMP1 (vacuole membrane protein 1), an ER-resident multispanning transmembrane protein, at both mRNA and protein levels in an experimental alcohol pancreatitis mouse model. More importantly, acinar cell-specific deletion of VMP1 in mice leads to increased ER stress and spontaneous pancreatitis. Damaged and excess ER can be removed via selective autophagy, termed as ER-phagy, which helps to maintain ER homeostasis and relieve ER stress. Our long- term goal of this proposal is to understand the molecular mechanisms for how alcohol decreases VMP1 in acinar cells and how VMP1-mediated autophagy protects against alcohol-induced pancreatitis. The objective of this proposal is to understand how VMP1-mediated ER-phagy is impaired by alcohol in acinar cells and how to pharmacologically maintain acinar cell ER homeostasis to protect against alcohol-induced pancreatitis. We will determine how genetic and pharmacological activation of TFEB-VMP1-mediated ER-phagy regulates ER homeostasis and protects against alcohol-induced pancreatitis. This proposal will establish a foundation for the development of novel therapeutics for treating alcoholic pancreatitis through modulation of VMP1-mediated ER-phagy to maintain acinar cell organelle homeostasis.