UNASSIGNED: The large global population of patients with metabolic dysfunction-associated steatotic liver disease (MASLD) has recently been shown to have an association with chronic kidney disease (CKD) due to a host of proposed mechanisms, one of which being lipoprotein dysmetabolism. Furthermore, metabolic comorbidities have been concurrently prevalent in MASLD and CKD independently. This study aimed at analyzing risk and predictive traits among an obese population for both MASLD and CKD.
UNASSIGNED: A retrospective chart review of 546 obese patients with a diagnosis of either MASLD or metabolic dysfunction-associated steatohepatitis between January 2020 and June 2021 was performed. Markers of liver and kidney function in addition to demographic data and renoprotective medications were recorded. Both univariable and multivariable linear regression analyses were performed to understand possible associations between MASLD markers, renal function, and markers of metabolic derangements.
UNASSIGNED: Univariate analysis revealed that increased age (P < .001), elevated alanine aminotransferase (defined as alanine aminotransferase ≥ 30 IU/L, P = .01), low albumin (P = .011), and increasing fibrosis-4 (FIB-4) (P = .005) were statistically associated with a reduced renal function. A reduction in glomerular filtration was associated with an increase in FIB-4 (effect size [beta] of a one-unit increase in glomerular filtration on FIB-4 = -0.013, P < .001) in univariate linear regression. In multivariate linear regression, type 2 diabetes (T2D) was independently associated with increased liver fibrosis (effect size of T2D on FIB-4 = 0.387925, P < .02).
UNASSIGNED: Our study shows that in a patient population with obesity and a diagnosis of MASLD, advanced fibrosis is independently associated with reduced renal function.

Hepatitis B Virus (HBV) is a stealthy and insidious pathogen capable of inducing chronic necro-inflammatory liver disease and hepatocellular carcinoma (HCC), resulting in over one million deaths worldwide per year. The traditional understanding of Chronic Hepatitis B (CHB) progression has focused on the complex interplay among ongoing virus replication, aberrant immune responses, and liver pathogenesis. However, the dynamic progression and crucial factors involved in the transition from HBV infection to immune activation and intrahepatic inflammation remain elusive. Recent insights have illuminated HBV\'s exploitation of the sodium taurocholate co-transporting polypeptide (NTCP) and manipulation of the cholesterol transport system shared between macrophages and hepatocytes for viral entry. These discoveries deepen our understanding of HBV as a virus that hijacks hepatocyte metabolism. Moreover, hepatic niche macrophages exhibit significant phenotypic and functional diversity, zonal characteristics, and play essential roles, either in maintaining liver homeostasis or contributing to the pathogenesis of chronic liver diseases. Therefore, we underscore recent revelations concerning the importance of hepatic niche macrophages in the context of viral hepatitis. This review particularly emphasizes the significant role of HBV-induced metabolic changes in hepatic macrophages as a key factor in the transition from viral infection to immune activation, ultimately culminating in liver inflammation. These metabolic alterations in hepatic macrophages offer promising targets for therapeutic interventions and serve as valuable early warning indicators, shedding light on the disease progression.

Dysregulation of the polyamine metabolism is common in different cancer types. SMOX is upregulated in hepatocellular carcinoma (HCC) but the relationship between SMOX and liver inflammation and fibrosis, remains unclear. In this issue of Clin Res Hepatol Gastroenterol, Hu and colleagues find targeting SMOX can alleviate liver cancer progression.

The chemokine (CCL)-chemokine receptor (CCR2) interaction, importantly CCL2-CCR2, involved in the intrahepatic recruitment of monocytes upon liver injury promotes liver fibrosis. CCL2-CCR2 antagonism using Cenicriviroc (CVC) showed promising results in several preclinical studies. Unfortunately, CVC failed in phase III clinical trials due to lack of efficacy to treat liver fibrosis. Lack of efficacy could be attributed to the fact that macrophages are also involved in disease resolution by secreting matrix metalloproteinases (MMPs) to degrade extracellular matrix (ECM), thereby inhibiting hepatic stellate cells (HSCs) activation. HSCs are the key pathogenic cell types in liver fibrosis that secrete excessive amounts of ECM causing liver stiffening and liver dysfunction. Knowing the detrimental role of intrahepatic monocyte recruitment, ECM, and HSCs activation during liver injury, we hypothesize that combining CVC and MMP (MMP1) could reverse liver fibrosis. We evaluated the effects of CVC, MMP1 and CVC + MMP1 in vitro and in vivo in CCl4-induced liver injury mouse model. We observed that CVC + MMP1 inhibited macrophage migration, and TGF-β induced collagen-I expression in fibroblasts in vitro. In vivo, MMP1 + CVC significantly inhibited normalized liver weights, and improved liver function without any adverse effects. Moreover, MMP1 + CVC inhibited monocyte infiltration and liver inflammation as confirmed by F4/80 and CD11b staining, and TNFα gene expression. MMP1 + CVC also ameliorated liver fibrogenesis via inhibiting HSCs activation as assessed by collagen-I staining and collagen-I and α-SMA mRNA expression. In conclusion, we demonstrated that a combination therapeutic approach by combining CVC and MMP1 to inhibit intrahepatic monocyte recruitment and increasing collagen degradation respectively ameliorate liver inflammation and fibrosis.

Liver diseases have a global prevalence of 25%, accounting for 4% of all deaths worldwide, and are associated with a 36% increased risk of fatal and nonfatal cardiovascular events. Metabolic dysfunction-associated steatotic liver disease constitutes the liver expression of metabolic syndrome and represents the primary type of liver disease. Microscopical analysis of biopsies, which allows the evaluation of a small portion of tissue with inferences made to the entire organ, is considered the gold standard for determining the presence of liver diseases. However, potential sampling errors in liver biopsies are conceivable because the obtained tissue represents only a tiny fraction of the entire liver mass and may not accurately reflect the true pathological state. Studies have demonstrated the existence of sampling errors in liver biopsies, particularly concerning the severity of inflammation, degree of fibrosis, and the presence of cirrhosis. Also, clinical studies have shown that histopathological abnormalities are better detected in humans when liver samples are collected from both the right and the left lobes. However, a gap exists in clinical investigation to clarify the role of differences between these lobes in improving the diagnostic and prognostic for liver diseases. Building upon the heterogeneous nature of pathological alterations observed in liver lobes, this perspective review provided recommendations to enhance the precision of diagnosis and prognostic accuracy of liver diseases.

UNASSIGNED: Dihydroartemisinin (DHA), a derivative of Artemisia annua, has been shown to possess anti-inflammatory properties. Besides, Yes-associated protein 1 (YAP1) plays a crucial role in maintaining liver homeostasis.
UNASSIGNED: This study used Yap1 Flox/Flox, Albumin-Cre mice with hepatocyte-specific Yap1 knockout (referred to as Yap1 LKO) and their control mice (Yap1 Flox/Flox, referred to as Yap1 Flox). The effect of Yap1 on lipid metabolism homeostasis was investigated through non-targeted metabolomic analysis of mouse liver. Subsequently, DHA was administered to Yap1 LKO mice to assess its potential as a treatment. Liver pathology was evaluated via H&E staining, and the levels of AST, ALT, and TG were quantified using biochemical assays. The contents of arachidonic acid (AA), prostaglandin E1 (PGE1), and leukotrienes (LT) in the liver were measured using ELISA, while the protein expressions of PLIN2, 5-lipoxygenase (5-LOX), and cyclooxygenase-2 (COX-2) were analyzed through IHC staining.
UNASSIGNED: Hepatocyte-specific Yap1 knockout activated the AA metabolic pathway, resulting in increased elevated levels of AA, PGE1, and LT levels, along with inflammatory cytokine infiltration. DHA mitigated the elevation of metabolites such as PGE1 and LT caused by the AA metabolic pathway activation by down-regulating the levels of COX-2 and 5-LOX in the liver of Yap1 LKO mice. Moreover, it alleviated the accumulation of lipid vacuoles and reduced triglyceride (TG) and perilipin-2 (PLIN2) levels in the liver of Yap1 LKO mice.
UNASSIGNED: Excessively low YAP1 expression induces liver inflammation and disturbances in lipid metabolism, whereas DHA modulated AA metabolism and mitigated liver inflammation by inhibiting the activation of 5-LOX and COX-2.

OBJECTIVE: Liver macrophages fulfill various homeostatic functions and represent an essential line of defense against pathogenic insults. However, it remains unclear whether a history of infectious disease in the liver instructs long-term alterations to the liver macrophage compartment.
METHODS: We utilized a curable model of parasitic infection invoked by the protozoan parasite Trypanosoma brucei brucei to investigate whether infection history can durably reshape hepatic macrophage identity and function. Employing a combination of fate mapping, single cell CITE-sequencing, single nuclei multiome analysis, epigenomic analysis, and functional assays, we studied the alterations to the liver macrophage compartment during and after the resolution of infection.
RESULTS: We show that T. b. brucei infection alters the composition of liver-resident macrophages, leading to the infiltration of monocytes that differentiate into various infection-associated macrophage populations with divergent transcriptomic profiles. Whereas infection-associated macrophages disappear post-resolution of infection, monocyte-derived macrophages engraft in the liver, assume a Kupffer cell (KC)-like profile and co-exist with embryonic KCs in the long-term. Remarkably, the prior exposure to infection imprinted an altered transcriptional program on post-resolution KCs that was underpinned by an epigenetic remodeling of KC chromatin landscapes and a shift in KC ontogeny, along with transcriptional and epigenetic alterations in their niche cells. This reprogramming altered KC functions and was associated with increased resilience to a subsequent bacterial infection.
CONCLUSIONS: Our study demonstrates that a prior exposure to a parasitic infection induces trained immunity in KCs, reshaping their identity and function in the long-term.
UNASSIGNED: Although the liver is frequently affected during infections, and despite housing a major population of resident macrophages known as Kupffer cells (KCs), it is currently unclear whether infections can durably alter KCs and their niche cells. Our study provides a comprehensive investigation into the long-term impact of a prior, cured parasitic infection, unveiling long-lasting ontogenic, epigenetic, transcriptomic and functional changes to KCs as well as KC niche cells, which may contribute to KC remodeling. Our data suggest that infection history may continuously reprogram KCs throughout life with potential implications for subsequent disease susceptibility in the liver, influencing preventive and therapeutic approaches.

Nod-like receptor family pyrin-containing protein 3 (NLRP3) inflammasome plays a pathologic role in metabolic dysfunction-associated steatohepatitis (MASH), but the molecular mechanism regulating the NLRP3 inflammasome activation in hepatocellular lipotoxicity remains largely unknown. Bromodomain-containing protein 4 (BRD4) has emerged as a key epigenetic reader of acetylated lysine residues in enhancer regions that control the transcription of key genes. The aim of this study is to investigate if and how BRD4 regulated the NLRP3 inflammasome activation and pyroptosis in MASH. Using the AML12 and primary mouse hepatocytes stimulated by palmitic acid (PA) as an in vitro model of hepatocellular lipotoxicity, we found that targeting BRD4 by genetic knockdown or a selective BRD4 inhibitor MS417 protected against hepatosteatosis; and this protective effect was attributed to inhibiting the activation of NLRP3 inflammasome and reducing the expression of Caspase-1, gasdermin D (GSDMD), interleukin (IL)-1β and IL-6. Moreover, BRD4 inhibition limited the voltage-dependent anion channel-1 (VDAC1) expression and oligomerization in PA-treated AML12 hepatocytes, thereby suppressing the NLRP3 inflammasome activation. Additionally, the expression of BRD4 enhanced in MASH livers of humans. Mechanistically, BRD4 was upregulated during hepatocellular lipotoxicity that in turn modulated the active epigenetic mark H3K27ac at the promoter regions of the Vdac and Gsdmd genes, thereby enhancing the expression of VDAC and GSDMD. Altogether, our data provide novel insights into epigenetic mechanisms underlying BRD4 activating the NLRP3 inflammasome and promoting GSDMD-mediated pyroptosis in hepatocellular lipotoxicity. Thus, BRD4 might serve as a novel therapeutic target for the treatment of MASH.

Hepatic stellate cells (HSCs) are responsible for liver fibrosis accompanied by its activation into myofibroblasts and the abundant production of extracellular matrix. However, the HSC contribution to progression of liver inflammation has been less known. We aimed to elucidate the mechanism in HSCs underlying the inflammatory response and the function of tumor necrosis factor α-related protein A20 (TNFAIP3). We established A20 conditional knockout (KO) mice crossing Twist2-Cre and A20 floxed mice. Using these mice, the effect of A20 was analyzed in mouse liver and HSCs. The human HSC line LX-2 was also used to examine the role and underlying molecular mechanism of A20. In this KO model, A20 was deficient in >80% of HSCs. Spontaneous inflammation with mild fibrosis was found in the liver of the mouse model without any exogenous agents, suggesting that A20 in HSCs suppresses chronic hepatitis. Comprehensive RNA sequence analysis revealed that A20-deficient HSCs exhibited an inflammatory phenotype and abnormally expressed chemokines. A20 suppressed JNK pathway activation in HSCs. Loss of A20 function in LX-2 cells also induced excessive chemokine expression, mimicking A20-deficient HSCs. A20 overexpression suppressed chemokine expression in LX-2. In addition, we identified DCLK1 in the genes regulated by A20. DCLK1 activated the JNK pathway and upregulates chemokine expression. DCLK1 inhibition significantly decreased chemokine induction by A20-silencing, suggesting that A20 controlled chemokine expression in HSCs via the DCLK1-JNK pathway. In conclusion, A20 suppresses chemokine induction dependent on the DCLK1-JNK signaling pathway. These findings demonstrate the therapeutic potential of A20 and the DCLK1-JNK pathway for the regulation of inflammation in chronic hepatitis.

ADAR1-mediated RNA editing establishes immune tolerance to endogenous double-stranded RNA (dsRNA) by preventing its sensing, primarily by MDA5. Although deleting Ifih1 (encoding MDA5) rescues embryonic lethality in ADAR1-deficient mice, they still experience early postnatal death, and removing other MDA5 signaling proteins does not yield the same rescue. Here, we show that ablation of MDA5 in a liver-specific Adar knockout (KO) murine model fails to rescue hepatic abnormalities caused by ADAR1 loss. Ifih1;Adar double KO (dKO) hepatocytes accumulate endogenous dsRNAs, leading to aberrant transition to a highly inflammatory state and recruitment of macrophages into dKO livers. Mechanistically, progranulin (PGRN) appears to mediate ADAR1 deficiency-induced liver pathology, promoting interferon signaling and attracting epidermal growth factor receptor (EGFR)+ macrophages into dKO liver, exacerbating hepatic inflammation. Notably, the PGRN-EGFR crosstalk communication and consequent immune responses are significantly repressed in ADAR1high tumors, revealing that pre-neoplastic or neoplastic cells can exploit ADAR1-dependent immune tolerance to facilitate immune evasion.