Manali Patel

Alcohol-associated liver disease (ALD) is driven by complex interactions among hepatic lipid accumulation, oxidative stress, inflammation, cell death, and disruption of the gut–liver axis. Therapeutic strategies capable of targeting multiple interconnected pathogenic pathways remain limited. In this study, we investigated the protective potential of graphene oxide nanoparticles (GNPs) in a chronic ethanol-fed rat model of ALD. Male Wistar rats were subjected to ethanol feeding and intermittently treated with GNPs (10 mg/kg) by oral gavage. Hepatic injury was assessed by biochemical parameters, histology, lipid accumulation, gene and miRNA expression, protein analysis, and gut microbiome profiling. Ethanol feeding induced hepatic steatosis, oxidative stress, apoptotic and necroptotic signaling, intestinal barrier disruption, gut dysbiosis, and activation of hepatic inflammatory pathways. GNP treatment markedly attenuated ethanol-induced lipid accumulation, normalized liver morphology, and reduced biochemical markers of liver injury. These effects were accompanied by restoration of antioxidant defenses, including Nrf2 and HO-1, and suppression of CYP2E1 expression and cell death–associated markers. In parallel, GNPs preserved intestinal architecture, maintained tight junction gene expression, and suppressed intestinal inflammatory responses. Gut microbiome analysis revealed partial restoration of ethanol-induced dysbiosis, including recovery of beneficial postbiotic-associated bacterial taxa. Improved intestinal homeostasis was associated with attenuation of hepatic TLR4-associated inflammatory signalling and modulation of macrophage-associated markers. Furthermore, GNP treatment partially normalized ethanol-induced dysregulation of miRNAs implicated in lipid metabolism, inflammation, and oxidative stress. Collectively, these findings demonstrate that GNPs exert a coordinated protective effect against ethanol-induced liver injury by modulating multiple pathological processes along the gut–liver axis. This multi-targeted activity highlights the therapeutic potential of graphene oxide nanoparticles as an intervention strategy for early-stage alcohol-associated liver disease.

The human gut microbiota (GM) functions as a vital immunometabolic organ that influences liver physiology through the gut–liver axis. Disruption of this carefully regulated network is increasingly acknowledged as a fundamental driver of steatotic liver disease (SLD) and liver fibrosis, conditions characterized by convergent inflammatory, metabolic, and immune‐mediated mechanisms. Microbial dysbiosis, combined with compromised intestinal barrier integrity, facilitates endotoxin translocation and elevates the portal delivery of microbial products and metabolites to the liver, thereby perpetuating chronic hepatic inflammation, hepatocellular injury, and progressive fibrogenic signaling. Among microbial‐derived metabolites, short‐chain fatty acids (SCFAs), produced via dietary fiber fermentation, serve as essential molecular links between diet, microbiota, and host responses. SCFAs possess pleiotropic effects that transcend intestinal homeostasis, extending to the regulation of hepatic metabolism and immune function. They influence these processes through mechanisms such as G‐protein–coupled receptor (GPR) activation, epigenetic modulation via histone deacetylase (HDAC) inhibition, and intracellular signaling cascades. In doing so, SCFAs modulate inflammatory pathways, including nuclear factor kappa B (NF‐κB) and inflammasome activation, while shaping innate and adaptive immune responses. Within the hepatic environment, these metabolites impact Kupffer cell (KC) activation, cytokine production, and hepatic stellate cell (HSC) activation, directly affecting the progression of steatosis and fibrogenesis. It is noteworthy that SCFA signaling is metabolite‐specific and context‐dependent. For example, butyrate consistently demonstrates barrier‐protective, anti‐inflammatory, and anti‐fibrotic properties, whereas acetate and propionate exhibit dual roles that depend on concentration, cellular targets, and disease stage. Emerging evidence further underscores extensive crosstalk between SCFAs and key regulatory pathways, including transforming growth factor‐beta (TGF‐β) and AMP‐activated protein kinase (AMPK) signaling, which coordinate responses to metabolic stress, inflammatory resolution, and extracellular matrix (ECM) remodeling. This review consolidates current advances in understanding the microbiota–SCFA–immune axis in SLD and hepatic fibrosis, highlighting how microbial metabolites coordinate immunometabolic signaling at the gut–liver interface. Elucidating this integrated network offers a robust conceptual framework for developing targeted, postbiotic‐ and pathway‐based therapeutic strategies aimed at restoring hepatic homeostasis and mitigating disease progression.

Chronic ethanol exposure activates inflammatory signaling pathways and inflicts hepatocellular damage, leading to alcohol‐associated liver diseases (ALDs). ALD is one of the major causes of global burden, yet there are no FDA‐approved treatment options available. This study evaluates the hepatoprotective effects of short‐chain fatty acids (SCFAs), mainly sodium acetate (NaA) and sodium butyrate (NaB), against ethanol‐induced inflammation and oxidative stress in both in vitro (Buffalo Rat Liver‐3A [BRL3A]) and in vivo (male Wistar rats) models. The treatment of NaA and NaB and their combination was given to the cell lines where maximum viability was observed at concentrations of 1.5 mM, 5 mM, and 0.1 mM + 1 mM, respectively. Additionally, reactive oxygen species (ROS) and nuclear morphology were assessed by fluorescent staining. For in vivo samples, the hepatic injury was analyzed by serum biochemical markers. Furthermore, hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) staining were employed, which provided structural and immunological alterations in hepatic tissue. RT‐qPCR profiled the expression levels of various pro‐inflammatory and anti‐inflammatory cytokines, as well as cytochrome P450 E1 (CYP2E1) and antioxidative stress markers. Moreover, enzyme‐linked immunosorbent assay (ELISA) quantified the essential protein targets such as TNF‐α, MCP‐1, IL‐1β, IL‐6, HO‐1, and Nrf2. The administration of NaA, NaB, and their combination resulted in reduced ROS levels and expression of pro‐inflammatory cytokines, preserved nuclear integrity, and neutrophil infiltration. These findings were further confirmed by in silico analysis and conserved amino acid interactions, and the affinities of NaA and NaB for TNF‐α and MCP‐1 were observed as compared to established inhibitors or activators. This study is the first demonstration to report the synergistic effects of NaA and NaB on the feedback loop of the nuclear factor kappa B (NF‐κB) signaling pathway, suggesting their potential as promising therapeutic candidates for alleviating alcohol‐induced hepatic damage.

The gut–liver–brain axis (GLB axis) plays a crucial role in maintaining metabolic, immune, and neurological homeostasis. The gut microbiota influences systemic health through its metabolites, including short‐chain fatty acids (SCFAs), bile acids (BAs), and tryptophan (Trp) derivatives, which regulate immune function, lipid metabolism, and neurotransmitter balance. Dysbiosis is an imbalance in gut microbiota that has been implicated in metabolic dysfuntion associated fatty liver disease (MAFLD), alcohol‐associated liver disease (AALD), and neuroinflammatory conditions such as schizophrenia. Increased gut permeability allows microbial byproducts like lipopolysaccharides (LPSs) to enter the liver and brain, activating inflammatory pathways that contribute to disease progression. Moreover, hepatic dysfunction can lead to neuroinflammation and cognitive impairments. Understanding the interplay between microbial metabolites and host physiology provides insight into novel therapeutic interventions. Strategies such as probiotics, prebiotics, synbiotics, fecal microbiota transfer (FMT), and postbiotics offer potential treatments to restore gut eubiosis and mitigate disease severity. This review highlights the mechanistic role of the GLB axis in health and disease, emphasizing microbiome‐targeted therapies as a promising avenue for managing metabolic and neuropsychiatric disorders. Trial Registration: ClinicalTrials.gov identifier: NCT04823676, NCT02496390, NCT06024681, NCT02721264