Mechanisms of Probiotics in Alcoholic Liver Disease

益生菌已被用于预防/治疗各种消化系统疾病，包括酒精性肝病（ALD）。 活的益生菌需要在肠道中定植以发挥其功能。不幸的是，潜在的疾病状态提供了 益生菌肠道定植的不利环境，这会降低益生菌的功能。近 几年来，我们发现LGG培养上清液（LGG，不含活菌）在预防中是有效的 在急性和慢性酒精暴露的小鼠实验模型中的ALD。然而，LGG上清液 发挥其治疗作用还不完全清楚。外来体是来源于细胞的纳米颗粒（NP）， 内吞作用，其作为细胞之间的传递物。最近的研究表明，细菌，无论是革兰氏阴性， 和革兰氏阳性菌产生NP。来自“坏”细菌的NP已被证明是 致病的然而，“好的”细菌-益生菌-衍生的NP尚未被研究。我们的初步研究 显示LGG衍生的外泌体样NP（LDNP）的施用有效地逆转了酗酒中的ALD。 慢性酒精暴露小鼠模型，表明益生菌LGGs可能通过LDNPs发挥其功能 在ALD。LDNPs给药显著增加肠AhR活性、IL-22、再生胰岛衍生3 （Reg 3）β和γ表达，其在维持肠道微生物群稳态中起关键作用， 防止细菌的肠道转胞吞作用。此外，LDNPs给药显著增加了肠内 上皮细胞（IEC）紧密连接和循环LPS浓度降低，与 肠Nrf 2信号传导，其已知用于保护肠屏障连接免受氧化应激诱导的损伤。 酒精的伤害。代谢组学分析显示LDNP含有高水平的微生物代谢物， 色氨酸，它们是AhR配体，表明LDNP可以激活肠道AhR信号传导。而且我们 证明姜外泌体样纳米颗粒（GDNP）优先被LGG吸收，这表明 GDNP可以作为益生元来增强LGG的作用。这些初步研究提供了 为我们的中心假设奠定了基础，即通过激活肠道AhR-Nrf 2信号传导，LDNPs增加了肠道 IL-22、Reg 3和紧密连接的表达，并调节肠道微生物群的稳态和增强肠道 屏障功能，导致ALD的抑制。我们将在以下三个具体目标中检验我们的假设： (1)确定细菌来源的NPs在ALD中的作用;（2）确定细菌来源的NPs的有益作用的机制。 （3）确定姜衍生的外泌体样纳米颗粒（GDNP）处理是否增强ALD中的LDNP; LDNP产生和AhR激动剂富集导致LDNP对ALD的改善的效果。完成 这项研究的结果预计将显著影响基于LGG的益生菌治疗剂在美国的发展。 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.