Intestine FXR activation by LGG-derived nanoparticles in alcohol-associated liver disease

大量研究报道了益生菌对酒精相关性肝病(ALD)的疗效。这 反映了科学界和医学界对确定替代性或附加性的强烈兴趣 治疗ALD的方法，目前还没有有效的或被广泛接受的治疗方案。但是，在 关于益生菌如何发挥其作用的深入分子知识缺乏。肌萎缩侧索硬化症患者通常表现为 胆汁淤积症的表现，这是一种由肝脏胆汁酸(BAS)积聚定义的肝脏病理， 毒性，是ALD肝细胞死亡和肝损伤的重要致病因素。肝内BA过多 浓度的增加部分是BA从头合成增加的结果。我们已经鉴定出一种miRNA(MiR194) 在饮酒的小鼠的肠道上皮细胞中过度表达。MmiR194抑制核受体 FXR被bas激活，调节肠源性激素FGF15的表达，它在 通过下调Cyp7A1抑制BA合成，在维持肝脏BA动态平衡中的作用。而当 FXR的BA激活已经被很好地研究了，但FXR是如何转录调控的还不是很清楚。我们的预赛 数据显示，益生菌鼠李糖乳杆菌GG衍生纳米粒(LDNPs)的给药量减少 小鼠肠道miR194，增加FXR和FGF15的表达，降低肝脏碱性磷酸酶和脂肪肝 和ALD一起。我们假设酒精既抑制转录表达又抑制配体介导的表达。 通过上调miR194和干扰肠道-微生物组-BA转化激活肠道中的FXR， 分别导致肝脏新生BA合成、脂肪生成和ALD增加，LDNP增加 补充剂可以减轻酒精引起的BA合成和脂肪生成的增加，并减轻ALD 通过抑制肠道miR194的表达，调节肠道微生物群BA的转化。这个 将追求以下具体目标来检验这一假说：目标1.确定肠道miR194在 酒精引起的肝脏BA合成和脂肪生成的失调。目标2.确定低核动力源在以下方面的作用 ALD时肠道miR194-FXR-FGF15信号的调控目的3.确定LDNP治疗是否 改变肠道微生物区系和BA谱，有助于ALD中FXR的激活。目的4.评估肠道 急性肝炎患者miR194和FXR活性的变化总而言之，这项拟议的研究代表了第一个分子 肠道miRNA如何调节肝脏BA动态平衡以及益生菌产品如何靶向肠道的研究 MiRNA194-FXR-FGF15在ALD中的表达。从这项研究中获得的结果可能会改善管理 对ALD的影响。

Numerous studies have reported the efficacy of probiotics for alcohol associated liver disease (ALD). This reflects a strong interest among the scientific and medical communities in identifying alternative or adjunctive approaches for ALD, for which there is no current effective or widely accepted therapeutic option. However, in depth molecular knowledge on how probiotics render their effects is lacking. Patients with ALD often exhibit manifestations of cholestasis, a liver pathology defined by accumulation of hepatic bile acids (BAs), which are toxic and are an important causative factor in hepatocyte death and liver injury in ALD. Excess hepatic BA concentration is partially a result of increased BA de novo synthesis. We have identified a miRNA (miR194) that is overexpressed in the intestinal epithelial cells in mice fed alcohol. MmiR194 suppresses a nuclear receptor FXR that is activated by BAs and regulates intestine-derived hormone, FGF15, expression, which plays a major role in maintaining hepatic BA homeostasis by suppressing BA synthesis via down-regulation of Cyp7A1. While the BA activation of FXR is well-studied, how FXR is regulated transcriptionally is less clear. Our preliminary data showed that probiotic Lactobacillus rhamnosus GG-derived nanoparticles (LDNPs) administration reduced intestinal miR194 and increased FXR and FGF15 expression, and decreased hepatic BAs and fatty liver in mice with ALD. We hypothesize that alcohol suppresses both the transcriptional expression and ligand-mediated activation of FXR in the intestine through upregulating miR194 and disturbing gut-microbiome-BA transformation, respectively, which lead to the increases in hepatic de novo BA synthesis, lipogenesis and ALD and that LDNP supplementation can diminish alcohol-induced increases in BA synthesis and lipogenesis and attenuate ALD through suppressing intestinal miR194 expression and regulating gut microbiome BA transformation. The following specific aims will be pursued to test this hypothesis: Aim 1. Determine the role of intestinal miR194 in the alcohol-induced dysregulation of liver BA synthesis and lipogenesis. Aim 2. Determine the role of LDNPs in the regulation of intestinal miR194-FXR-FGF15 signaling in ALD. AIM 3. Determine whether LDNP treatment alters gut microbiota and BA profile that contribute to FXR activation in ALD. Aim 4. Evaluate the intestinal miR194 and FXR activity in patients with AH. In summary, the proposed study represents the first molecular study on how intestinal miRNA regulates liver BA homeostasis and how a probiotic product targets intestinal miRNA194-FXR-FGF15 singling in ALD. The results obtained from this study may lead to improved management of ALD.