Mechanisms of Probiotics in Alcoholic Liver Disease

益生菌已被用于预防/治疗包括酒精性肝病(ALD)在内的各种消化系统疾病。 活的益生菌需要在肠道中定植才能发挥它们的作用。不幸的是，潜在的疾病状态提供了 不利于益生菌肠道定植的环境，降低了益生菌的作用。最后一位 几年来，我们证明了LGG培养上清(LGGs，不含活菌)对预防该病是有效的。 对急性和慢性酒精暴露小鼠模型的酒精性痴呆的影响。然而，LGG上清液如何 发挥其治疗作用尚不完全清楚。胞外体是一种来源于细胞的纳米颗粒。 作为细胞间传递者的内吞作用。最近的研究表明，细菌，无论是革兰氏阴性 和革兰氏阳性，产生NP。从“坏”细菌中提取的NPs已被证明是 致病的。然而，“好的”细菌、益生菌衍生的NPs还没有被研究过。我们的初步研究 研究表明，给予LGG衍生的外切体样NPs(LDNPs)可有效逆转大鼠酒精性肝病。 小鼠慢性酒精暴露模型，提示益生菌LGGs可能通过LDNPs发挥作用 在ALD。LDNPs显著增加肠道AhR活性、IL-22、再生胰岛来源3 (Reg3)β和伽马表达，这在维持肠道微生物区系动态平衡和 预防细菌性肠穿孔。此外，LDNPs的使用显著增加了肠道 上皮细胞(IEC)紧密连接和循环内毒素浓度下降，与上调 肠道Nrf2信号转导，已知可保护肠道屏障连接免受氧化应激诱导 酒精造成的损害。代谢组学分析显示LDNPs含有高水平的微生物代谢物 色氨酸，这是AhR的配体，表明LDNPs可能激活肠道AhR信号。此外，我们 证明生姜外切体状纳米粒(GDNPs)优先被LGG摄取，这表明 GDNP可能作为一种益生素来增强LGG的作用。这些初步研究提供了 我们的中心假设的基础是，通过激活肠道AhR-Nrf2信号，LDNPs增加了肠道 IL-22、Reg3和紧密连接的表达，调节肠道微生物区系动态平衡，增强肠道功能 屏障功能，导致ALD的抑制。我们将通过以下三个具体目标来验证我们的假设： (1)确定细菌来源的NPs在ALD中的作用；(2)确定其有益作用的机制 LDNPs在ALD中的作用；(3)确定生姜衍生的外切体样纳米粒(GDNPs)治疗是否增强 LDNP的产生和AhR激动剂的浓缩导致LDNPs抗ALD效果的改善。完成 这项研究的结果预计将对以免疫球蛋白为基础的益生菌疗法的发展产生重大影响。 酒精相关性肝病的治疗。

Probiotics have been used to prevent/treat a variety of digestive diseases including alcoholic liver disease (ALD). Live probiotics need to colonize the gut to exert their function. Unfortunately, underlying disease states provide an unfavorable environment for probiotic bacterial gut colonization, which diminishes probiotics’ function. In last few years, we showed that LGG culture supernatant (LGGs, without live bacteria) was effective in the prevention of ALD in experimental models of acute and chronic alcohol exposure in mice. However, how LGG supernatant exerts its therapeutic effects is not fully understood. Exosomes are nanoparticles (NPs) derived from cell endocytosis which act as transmitters between cells. Recent studies show that bacteria, both Gram-negative and Gram-positive, produce NPs. The NPs derived from “bad” bacteria have been demonstrated to be pathogenic. However, “good” bacteria-, probiotics-derived NPs have not been studied. Our preliminary study showed that administration of LGG-derived exosome-like NPs (LDNPs) effectively reversed ALD in binge-on- chronic alcohol exposure mouse model, suggesting that probiotic LGGs may exert its function through LDNPs in ALD. LDNPs administration markedly increased intestinal AhR activity, IL-22, regenerating islet-derived 3 (Reg3) beta and gamma expression, which play a key role in maintaining gut microbiota homeostasis and preventing bacterial intestinal transcytosis. In addition, LDNPs administration significantly increased intestinal epithelial cell (IEC) tight junctions and decreased circulating LPS concentration, associated with upregulation of intestinal Nrf2 signaling, which is known for protecting intestinal barrier junctions against oxidative stress-induced damage by alcohol. Metabolomic analysis revealed that LDNPs contain high levels of microbial metabolites of tryptophan, which are AhR ligands, indicating LDNPs may activate intestinal AhR signaling. Furthermore, we demonstrated that ginger exosome-like nanoparticles (GDNPs) are preferentially taken up by LGG, suggesting that GDNP may serve as a prebiotic to enhance the effects of LGG. These preliminary studies provide the groundwork for our central hypothesis that, by activating intestinal AhR-Nrf2 signaling, LDNPs increase intestinal expression of Il-22, Reg3 and tight junctions, and modulate gut microbiota homeostasis and enhance intestinal barrier function, leading to the suppression of ALD. We will test our hypothesis in following three specific aims: (1) Determine the role of bacteria-derived NPs in ALD; (2) Define the mechanisms of the beneficial effect of LDNPs in ALD; (3) Determine whether ginger-derived exosome-like nanoparticles (GDNPs) treatment enhances LDNP production and AhR agonist enrichment that lead to improved effects of LDNPs against ALD. Completion of this study is expected to significantly impact the development of LGG-based probiotic therapeutics in the treatment of alcohol-associated liver diseases.