探討來自仿人體腸道菌鼠的微生物基因體數據篩選出之新興腸道菌株對於代謝性脂肪肝炎進展的影響

Abstract

代謝性脂肪肝病（MAFLD）是全球常見的慢性肝病，約影響全球30%的人口。MAFLD涵蓋了廣泛的肝臟疾病範疇，從脂肪肝開始逐漸發展為代謝性脂肪肝炎（MASH），最終可能導致肝硬化甚至肝癌。多項研究顯示，人體腸道菌在MAFLD的進展中透過腸肝軸發揮重要作用。因此，許多研究成功利用次世代益生菌（NGP）來預防或治療脂肪肝病。為了探討腸道菌群對MAFLD的作用，我們的研究團隊建立了仿人體腸道菌鼠（HMA）模型，將來自六位具有不同程度MAFLD的肥胖患者的糞便微生物移植到無菌小鼠中，並研究其與MAFLD疾病嚴重程度相關的表徵。我們觀察到在六位供體中，HMA小鼠中供體D的（HMA_D組）腸道菌對抗MASH表現出最佳的肝保護效果。腸道菌分析顯示，HMA_D小鼠中Roseburia hominis和Bacteroides stercoris的豐富度較高，這可能有助於預防MAFLD疾病進展。因此，本研究旨在探討來自仿人體腸道菌鼠的微生物基因體數據篩選出之新興腸道菌株對於Gubra-Amylin NASH（GAN）飲食誘導小鼠之代謝性脂肪肝炎進展的影響。結果顯示，Roseburia hominis和Bacteroides stercoris在介入GAN 飲食誘導的小鼠肝損傷方面效果有限。然而，當這些菌株以混合菌液形式給予時，MAFLD的發生率呈下降的趨勢，顯示混合菌株比單一菌株對預防MAFLD更有效果。此外，本研究發現給予Roseburia hominis或Bacteroides stercoris的小鼠能有效減少肝臟腫大，並顯著降低血漿總膽固醇。然而，這些改善的背後機制尚不清楚，需進一步探討。本實驗的發現之一是，Roseburia hominis 透過上調胰島素訊號通路中的關鍵分子，如IRS1和PI3K，來緩解MAFLD小鼠的胰島素阻抗，並顯著降低空腹血糖。最後，腸道菌群分析顯示，MAFLD小鼠的腸道菌群失衡，表現為有益菌減少和有害菌增加。然而，Roseburia hominis或Bacteroides stercoris對腸道菌群失衡的逆轉效果有限。總結來說，Roseburia hominis和Bacteroides stercoris在緩解MAFLD小鼠的肝損傷和代謝紊亂方面表現出一定的效果，且混合菌株比單一菌株更具療效。然而，它們對腸道菌群失衡的影響及對MAFLD進展的整體影響仍然有限，這表明需要進一步探索。

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a prevalent chronic liver disease worldwide, affecting approximately 30% of the global population. MAFLD encompasses a broad spectrum of liver disease, starting with steatosis and progressing to metabolic dysfunction-associated steatohepatitis (MASH), which can lead to cirrhosis and even hepatocellular carcinoma. Several studies indicate that the human gut microbiota plays an important role in the progression of MAFLD through the gut-liver axis. Consequently, numerous studies have successfully used next-generation probiotics (NGP) for preventive or therapeutic functions against fatty liver disease. To investigate the role of gut microbiota on MAFLD, our research team developed a model of human microbiota-associated (HMA) mice by transplanting fecal microbiota obtained from six obese patients with different degrees of MAFLD to germ-free mice and examining the phenotype associated with MAFLD. We observed that among six donors, the gut microbiota of donor D in HMA mice (HMA_D group) exhibited the best hepatoprotective effect against MASH. Gut microbiota analysis revealed that Roseburia hominis and Bacteroides stercoris were enriched in HMA_D mice, which might be beneficial for MAFLD amelioration. Therefore, this study aims to verify the relationship between the novel intestinal microbiome derived from the microbiomics data of HMA mice and the progression of MASH in a Gubra-Amylin NASH (GAN) mice model. The results indicated that R. hominis and B. stercoris had limited effects in preventing GAN diet-induced liver injury in mice. However, when administered as a combined bacterial suspension, there was a decreasing trend in MAFLD incidence, suggesting that the mixed strains were more effective in preventing MAFLD compared to individual strains. Moreover, this study found that administering R. hominis or B. stercoris to mice effectively decreased liver weight gain and significantly reduced plasma total cholesterol. However, the underlying mechanisms behind these improvements remain unclear and warrant further investigation. What’s more, an important finding of this experiment is that R. hominis alleviated insulin resistance in MAFLD mice by upregulating key molecules in the insulin signaling pathway, such as IRS1 and PI3K, and significantly lowered fasting blood glucose levels. Finally, gut microbiota analysis revealed an imbalance in MAFLD mice, characterized by a reduction in beneficial bacteria and an increase in harmful bacteria. However, the reversal effects of R. hominis and B. stercoris were limited. In summary, R. hominis and B. stercoris demonstrated some efficacy in alleviating liver damage and metabolic disturbances in MAFLD mice, with combined strains showing better results than individual strains. However, their impact on gut microbiota imbalance and the overall progression of MAFLD was limited, suggesting the need for further exploration.