Urolithin A ameliorates liver fibrosis by modulating the gut microbiota-bile acid-FXR axis

Abstract

Abstract: Abstract: Object: Urolithin A (UroA), a gut microbiota-derived metabolite of ellagic acid, exhibits hepatoprotective effects; however, its role in liver fibrosis (LF) remains?poorly understood. This study?aimed to?investigate the protective effects of Urolithin A (UroA) against liver fibrosis (LF)?through the gut-liver axis,?with a particular emphasis on?its regulatory mechanisms in the gut microbiota-bile acid (BA) axis. Method: The therapeutic potential of UroA was evaluated?in?a CCl?-induced mouse model of LF (in vivo) and TGF-β1-activated HSC-LX2 cells (in vitro). Liver injury markers (ALT, AST, ALP), fibrosis indicators (α-SMA, COL1A1, TGF-β1), and inflammatory cytokines (TNF-α, IL-6, IL-1β) were assessed?using?histopathology, biochemical assays, RT-qPCR, and Western blotting. Gut microbiota composition was analyzed by 16S rDNA sequencing,?while?intestinal barrier integrity was?evaluated?by immunohistochemical detection of tight junction proteins (ZO-1, Occludin). Targeted metabolomics was performed to analyze BA metabolism, and the expression of key FXR signaling pathway components (CYP7A1, CYP27A1, CYP8B1, BSEP, and MRP2) was examined. Results: UroA significantly reduced serum ALT, AST, and ALP levels, decreased hepatic hydroxyproline content, and mitigated liver injury and collagen deposition. Moreover, UroA downregulated the expression of fibrogenic markers (α-SMA, COL1A1, and TGF-β1). 16S rDNA sequencing revealed that UroA reshaped the gut microbiota composition, significantly increasing the abundance of beneficial genera such as Lawsonibacter, Paramuribaculum, Oscillibacter, Barnesiella, and Akkermansia, while reducing the levels of the pro-inflammatory genus Allobaculum. Furthermore, UroA?strengthened?intestinal barrier function by upregulating tight junction proteins (ZO-1, Occludin) and?restored?BA homeostasis by?reducing?the FXR antagonist T-β-MCA.?Mechanistic studies revealed that UroA activated the FXR pathway, thereby inhibiting key bile acid synthesis enzymes (CYP7A1, CYP27A1, and CYP8B1) while promoting the expression of BA efflux transporters (BSEP and MRP2). Conclusion: UroA?mitigates?LF?via?the gut microbiota–BA–FXR axis,?modulating?gut microbial ecology,?preserving?intestinal barrier integrity, and?normalizing?BA metabolism. These findings?provide?a novel therapeutic strategy?for?LF.

Key words: Bile acid metabolism, farnesoid X receptor, gut microbiota, liver fibrosis, urolithin A

CLC Number:

Li-Hua LI Qi CUI Xiao-Xia SHEN. Urolithin A ameliorates liver fibrosis by modulating the gut microbiota-bile acid-FXR axis[J]. FOOD SCIENCE.

References

[1]Sun Y M, Chen S Y, You H.Regression of liver fibrosis: evidence and challenges[J].Chin Med J (Engl), 2020, 133(14):1696-1702 [2]Chang T T, Liaw Y F, Wu S S, et al.Long-term entecavir therapy results in the reversal of fibrosiscirrhosis and continued histological improvement in patients with chronic hepatitis B[J].Hepatology, 2010, 52(3):886-893 [3]Rupcic R V, Bojanic K, Smolic M, et al.An update on efficacy and safety of emerging hepatic antifibrotic agents[J].J Clin Transl Hepatol, 2021, 9(1):60-70 [4]Zhang Y L, Li Z J, Gou H Z, et al.The gut microbiota-bile acid axis: a potential therapeutic target for liver fibrosis[J]. Front Cell Infect Microbiol, 2022, 12: 945368. DOI: 10.3389/fcimb.2022.945368.[J].Front Cell Infect Microbiol, 2022, 12(9): 945368-无 [5]Dai X, Hou H, Zhang W, et al.Microbial metabolites: critical regulators in NAFLD[J]. Front Microbiol, 2020, 11: 567654. DOI: 10.3389/fmicb.2020.567654.[J].Front Microbiol, 2020, 11(无):567654-无 [6]Clifford B L, Sedgeman L R, Williams K J, et al.FXR activation protects against NAFLD via bile-acid-dependent reductions in lipid absorption[J].Cell Metab, 2021, 33(8):1671-1684 [7]Gupta A, Singh A K, Kumar R, et al.Neuroprotective potential of ellagic acid: a critical review[J].Adv Nutr, 2021, 12(4):1211-1238 [8]Cerdá B, Espín J C, Parra S, et al.The potent in vitro antioxidant ellagitannins from pomegranate juice are metabolised into bioavailable but poor antioxidant hydroxy-6H-dibenzopyran-6-one derivatives by the colonic microflora of healthy humans[J].Eur J Nutr, 2004, 43(4):205-220 [9]Ryu D, Mouchiroud L, Andreux P A, et al.Urolithin A induces mitophagy and prolongs lifespan in Celegans and increases muscle function in rodents[J].Nat Med, 2016, 22(8):879-888 [10]Ghosh S, Singh R, Vanwinkle Z M, et al.Microbial metabolite restricts 5-fluorouracil-resistant colonic tumor progression by sensitizing drug transporters via regulation of FOXO3-FOXM1 axis[J].Theranostics, 2022, 12(12):5574-5595 [11]Tao H, Li W, Zhang W, et al.Urolithin A suppresses RANKL-induced osteoclastogenesis and postmenopausal osteoporosis by, suppresses inflammation and downstream NF-κB activated pyroptosis pathways[J]. Pharmacol Res, 2021, 174: 105967. DOI: 10.1016/j.phrs.2021.105967.[J].Pharmacol Res, 2021, 174(无):105967-无 [12]Gao Z, Yi W, Tang J, et al.Urolithin A protects against acetaminophen-induced liver injury in mice via sustained activation of Nrf2[J].Int J Biol Sci, 2022, 18(5):2146-2162 [13]Karim S, Madani B, Burzangi A S, et al.Urolithin A' s antioxidative, anti-Inflammatory, and antiapoptotic activities mitigate doxorubicin-induced liver injury in wistar rats[J]. Biomedicines, 2023, 11(4). DOI: 10.3390/biomedicines11041125.[J].Biomedicines, 2023, 11(4):1125-无 [14]Chen P, Lei J, Chen F, et al.Ameliorative effect of urolithin A on d-gal-induced liver and kidney damage in aging mice via its antioxidative,anti-inflammatory and antiapoptotic properties[J].RSC Adv, 2020, 10(14):8027-8038 [15]Zhang C, Song Y, Yuan M, et al.Ellagitannins-derived intestinal microbial metabolite urolithin A ameliorates fructose-driven hepatosteatosis by suppressing hepatic lipid metabolic reprogramming and inducing lipophagy[J].J Agric Food Chem, 2023, 71(9):3967-3980 [16]Yan M, Xie Y, Yao J, et al.The dual-mode transition of myofibroblasts derived from hepatic stellate cells in liver fibrosis[J]. Int J Mol Sci, 2023, 24(20). DOI: 10.3390/ijms242015460.[J].Int J Mol Sci, 2023, 24(20):15460-无 [17]Kisseleva T, Brenner D.Molecular and cellular mechanisms of liver fibrosis and its regression[J].Nat Rev Gastroenterol Hepatol, 2021, 18(3):151-166 [18]Xu S, Chen Y, Miao J, et al.Esculin inhibits hepatic stellate cell activation and CCl4-induced liver fibrosis by activating the Nrf2/GPX4 signaling pathway[J]. Phytomedicine, 2024, 128: 155465. DOI: 10.1016/j.phymed.2024.155465.[J].Phytomedicine, 2024, 128(无):155465-无 [19]Zhou B, Yuan Y, Zhang S, et al.Intestinal flora and disease mutually shape the regional immune system in the intestinal tract[J]. Front Immunol, 2020, 11: 575. DOI: 10.3389/fimmu.2020.00575.[J].Front Immunol, 2020, 11(无):575-无 [20]Martinez-Gili L, Pechlivanis A, McDonald J, et al.Bacterial and metabolic phenotypes associated with inadequate response to ursodeoxycholic acid treatment in primary biliary cholangitis[J].Gut Microbes, 2023, 15(1):2208501-无 [21]Chen W, Wei Y, Xiong A, et al.Comprehensive analysis of serum and fecal bile acid profiles and interaction with gut microbiota in primary biliary cholangitis[J].Clin Rev Allergy Immunol, 2020, 58(1):25-38 [22]Xie G, Jiang R, Wang X, et al.Conjugated secondary 12α-hydroxylated bile acids promote liver fibrogenesis[J]. EBioMedicine, 2021, 66: 103290. DOI: 10.1016/j.ebiom.2021.103290.[J].EBioMedicine, 2021, 66(无):103290-无 [23]Sun L, Cai J, Gonzalez F J.The role of farnesoid X receptor in metabolic diseases,and gastrointestinal and liver cancer[J].Nat Rev Gastroenterol Hepatol, 2021, 18(5):335-347 [24]Sayin S I, Wahlstr?m A, Felin J, et al.Gut microbiota regulates bile acid metabolism by reducing the levels of tauro-beta-muricholic acid,a naturally occurring FXR antagonist[J].Cell Metab, 2013, 17(2):225-235 [25]Gilgenkrantz H, Mallat A, Moreau R, et al.Targeting cell-intrinsic metabolism for antifibrotic therapy[J].J Hepatol, 2021, 74(6):1442-1454 [26]Zhang X, Zhang L, Ji L, et al.Pien Tze Huang plus entecavir improves hepatic fibrosis in Chinese patients with chronic hepatitis B[J]. Phytomedicine, 2025, 142: 156741. DOI: 10.1016/j.phymed.2025.156741.?[J].Phytomedicine, 2025, 142(无):156741-无 [27]Sanyal A J, Ratziu V, Loomba R, et al.Results from a new efficacy and safety analysis of the REGENERATE trial of obeticholic acid for treatment of pre-cirrhotic fibrosis due to non-alcoholic steatohepatitis[J].J Hepatol, 2023, 79(5):1110-1120 [28]Cani P D, Depommier C, Derrien M, et al.Akkermansia muciniphila: paradigm for next-generation beneficial microorganisms[J].Nat Rev Gastroenterol Hepatol, 2022, 19(10):625-637 [29]Grander C, Adolph T E, Wieser V, et al.Recovery of ethanol-induced Akkermansia muciniphila depletion ameliorates alcoholic liver disease[J].Gut, 2018, 67(5):891-901 [30]Nie Q, Luo X, Wang K, et al.Gut symbionts alleviate MASH through a secondary bile acid biosynthetic pathway[J].Cell, 2024, 187(11):2717-2734 [31]Oguri N, Miyoshi J, Nishinarita Y, et al.Akkermansia muciniphila in the small intestine improves liver fibrosis in a murine liver cirrhosis model[J].NPJ Biofilms Microbiomes, 2024, 10(1):81-无 [32]Zhang Y, Xu D, Cai X, et al.Gut commensal barnesiella intestinihominis ameliorates hyperglycemia and liver metabolic disorders[J].Adv Sci (Weinh), 2025, 12(8):e2411181-无 [33]van Muijlwijk G H, van Mierlo G, Jansen P, et al.Identification of Allobaculum mucolyticum as a novel human intestinal mucin degrader[J].Gut Microbes, 2021, 13(1):1966278- [34]Liu C, Du MX, Xie L S, et al.Gut commensal Christensenella minuta modulates host metabolism via acylated secondary bile acids[J].Nat Microbiol, 2024, 9(2):434-450 [35]Liu Y, Chen K, Li F, et al.Probiotic Lactobacillus rhamnosus GG prevents liver fibrosis through inhibiting hepatic bile acid synthesis and enhancing bile acid excretion in mice[J].Hepatology, 2020, 71(6):2050-2066 [36]Zhang L, Chen J, Yang X, et al.Hepatic Zbtb18 (Zinc Finger and BTB Domain Containing 18) alleviates hepatic steatohepatitis via FXR (Farnesoid X Receptor)[J].Signal Transduct Target Ther, 2024, 9(1):20-无