Hepatic NCoR1 deletion exacerbates alcohol-induced liver injury in mice by promoting CCL2-mediated monocyte-derived macrophage infiltration

Molecular mechanisms of alcohol-associated liver disease-ferroptosis and autophagy crosstalk

Alcohol-associated liver disease (ALD) is a chronic liver injury caused by prolonged heavy drinking and its pathogenesis is extremely complex. According to current researches, ethanol metabolism and the generation of some of its related metabolites, including acetaldehyde and reactive oxygen species, are significant contributors to hepatocyte toxicity. These substances-induced lipid metabolism disorders, inflammatory response, mitochondrial damage, and cellular oxidative stress are important factors that lead to liver injury. Ethanol has been shown in numerous studies to exacerbate ALD by disrupting autophagy via a variety of mechanisms. ALD can be somewhat alleviated by activating autophagy, which plays a significant role in the development of ALD by removing accumulated protein polymers, damaged mitochondria, and excess lipid droplets from hepatocytes. Furthermore, persistent alcohol use raises serum iron levels, which in turn causes hepatocytes to absorb more iron. This, in turn, encourages iron loading in the liver's and other organs' parenchymal and nonparenchymal cells, finally resulting in ferroptosis. Both ferroptosis and autophagy are significant types of controlled cell death, and new research has revealed that cellular autophagy and a variety of signaling pathways play a key role in the initiation and progression of ferroptosis. Alcohol and iron both have the ability to cause oxidative stress on their own, thus their combined effects hasten liver damage. Iron loading, on the other hand, accelerates the development of ALD by triggering mitochondrial oxidative stress and activating signaling pathways and proteins linked to Ferritinophagy. Thus, we think that a new approach to treating ALD in the future will involve examining the interaction between ferroptosis and mitochondrial autophagy based on iron overload.

Alcohol intake exacerbates experimental autoimmune prostatitis through activating PI3K/AKT/mTOR pathway-mediated Th1 differentiation

Background

Epidemiological investigations have revealed a significant association between alcohol consumption and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Nevertheless, the potential mechanisms are still inadequately revealed. This research aimed to investigate the impact of alcohol on CP/CPPS using an animal model and to elucidate the underlying mechanisms.

Methods

We first established the widely used animal model for CP/CPPS, experimental autoimmune prostatitis (EAP). During the induction of EAP, mice were fed with alcohol or control diet. The HE staining, ELISA, and behavioral experiments were employed to assess the severity of inflammation in EAP mice and EAP-alcohol mice. Patients with a history of chronic alcohol consumption were also included to evaluate the effects of chronic alcohol consumption on CP/CPPS. Subsequently, proteomic analysis, flow cytometry, immunofluorescence, Western blotting, and immunohistochemistry were utilized to investigate the underlying mechanism involved both in vivo and in vitro.

Results

HE staining, ELISA, and behavioral experiments showed that alcohol exacerbated the severity of EAP in mice and patients. Proteomic and KEGG pathway analyses showed that abnormal Th1 differentiation and PI3K/AKT/mTOR pathway were significantly enriched. Subsequent mechanistic research showed that alcohol significantly activated PI3K/AKT/mTOR pathway and increased the Th1 cell differentiation both in vivo and in vitro. In contrast, PI3K inhibitor LY294002 and shRNA-PI3K plasmid inhibited PI3K/AKT/mTOR pathway activation, reduced Th1 cell differentiation, and alleviated EAP inflammation severity, respectively.

Conclusion

Our study is the first to demonstrate that alcohol intake promotes Th1 cell differentiation and exacerbates EAP by activating the PI3K/AKT/mTOR pathway. Additionally, the role of LY294002 in inhibiting PI3K/AKT/mTOR pathway to relieve EAP suggests that it can serve as a promising therapeutic target for CP/CPPS.

Unveiling the interplay between hepatocyte SATB1 and innate immunity in autoimmune hepatitis

BACKGROUND

Investigating the function of SATB1 in hepatocytes is essential for developing therapeutic strategies for autoimmune hepatitis (AIH). Although SATB1 has been extensively studied in immune cells, its specific activity in hepatocytes within the context of AIH remains unclear.

METHODS

SATB1 expression in AIH hepatocytes was assessed by qRT-PCR, Western blotting, flow cytometry, and immunohistochemistry. In vivo modulation used RNA interference viruses and overexpression plasmids. SATB1's proinflammatory effects were analyzed with protein microarray, immunohistochemistry, and flow cytometry. Chemotactic effects on RAW264.7 macrophages were tested in vitro, with mechanisms explored by dual-luciferase assays and CUT&RUN qPCR. Liver injury was evaluated by histopathology and serum biochemistry.

RESULTS

SATB1 was significantly upregulated in hepatocytes of AIH patients and models, showing a stronger increase in hepatocytes than in CD45+ cells, and positively correlated with liver injury severity. In vivo RNAi-mediated SATB1 inhibition reduced liver inflammation, while SATB1 overexpression aggravated AIH progression. Both interference and overexpression experiments confirmed that SATB1 promotes liver injury by facilitating the infiltration of proinflammatory (Ly6Chigh) macrophage. In vitro, supernatant from SATB1-overexpressing hepatocytes enriched chemokine signaling pathways, leading to increased CCL2 expression and release, which attracted macrophages and drove their proinflammatory polarization. Mechanistically, SATB1 promoted CCL2 transcription by binding to its DNA and recruiting p300/CBP.

CONCLUSIONS

This study reveals that SATB1 is upregulated in hepatocytes in AIH. Elevated SATB1 levels in liver cells contribute to autoimmune hepatitis by increasing CCL2 expression, promoting the recruitment of inflammatory monocyte-derived macrophage, and reshaping the composition of the liver immune microenvironment.

Saikogenin A improves ethanol-induced liver injury by targeting SIRT1 to modulate lipid metabolism

Chronic alcohol consumption can lead to alcohol live disease (ALD). Steatosis is a critical hallmark of ALD, making it an important stage for therapeutic intervention. Saikosaponin A (SSa), a compound found in Radix Bupleuri, has previously shown promising hepatoprotective, anti-inflammatory, and antioxidant properties. However, its role in ALD remains understudied. We employ cell-based screening models and a chronic-plus-binge ethanol-fed mouse model to investigate the protective mechanisms of SSa and its metabolite Saikogenin A (SGA), against ethanol-induced hepatocyte injury. Our RNA-seq analysis in mice unveils that SSa primarily acts through the mTOR and PPAR-α signaling pathways in the liver. Biophysical assays and loss of function experiments confirm SGA directly binds to and modulates the activity of SIRT1 protein, mitigating ethanol-induced cell injury via the SIRT1-mTOR-PPAR-α axis. Furthermore, SGA displays a survival prolonging advantage compared to resveratrol for treating ALD. This suggests SGA holds promise as a potential therapeutic agent for ALD.

Glycyrrhizic acid alleviates concanavalin A-induced acute liver injury by regulating monocyte-derived macrophages

Autoimmune hepatitis (AIH) is characterized by persistent liver inflammation induced by aberrant immune responses. Glycyrrhizic acid (GA), a prominent bioactive ingredient of licorice, has shown potential as a safe and effective treatment for AIH. However, the immune regulatory mechanism by which GA exerts its therapeutic effect on AIH remains elusive. In this study, we found that GA intervention significantly alleviated ConA-induced acute liver injury in mice. Cytometry by time-of-flight (CyTOF) analysis revealed that GA increased the abundance of anti-inflammatory F4/80loCD11bhiMHCIIhi MoMF-1 and decreased the abundance of pro-inflammatory F4/80loCD11bhiiNOShi MoMF-3. Multiplex immunofluorescence demonstrated the infiltration of MoMFs in liver tissues. Single-cell RNA sequencing (scRNA-seq) analysis indicated that GA facilitated the immune activation in MoMFs, regulated gene expression of diverse cytokines secreted by MoMFs, and played a role in shaping the immune microenvironment. By integrating the results of CyTOF with scRNA-seq, our study comprehensively elucidates the immune landscape of ConA-induced liver injury following GA intervention, advancing the understanding of GA's mechanism of action. However, it is important to note that some single-cell data in this study remain raw and require further processing and annotation. Our findings suggest that GA alleviates ConA-induced acute liver injury by regulating the function of MoMFs, opening potential avenues for AIH treatment and management, and providing a theoretical basis for the design of novel MoMFs-centered immunotherapies.

Foxo1 is an iron-responsive transcriptional factor regulating systemic iron homeostasis

The liver plays a crucial role in maintaining systemic iron homeostasis by secreting hepcidin, which is essential for coordinating iron levels in the body. Imbalances in iron homeostasis are associated with various clinical disorders related to iron deficiency or iron overload. Despite the clinical significance, the mechanisms underlying how hepatocytes sense extracellular iron levels to regulate hepcidin synthesis and iron storage are not fully understood. In this study, we identified Foxo1, a well-known regulator of macronutrient metabolism, which translocates to the nucleus of hepatocytes in response to high-iron feeding, holo-transferrin, and bone morphogenetic protein 6 (BMP6) treatment. Furthermore, Foxo1 plays a crucial role in mediating hepcidin induction in response to both iron and BMP signals by directly interacting with evolutionally conserved Foxo binding sites within the hepcidin promoter region. These binding sites were found to colocalize with Smad-binding sites. To investigate the physiological relevance of Foxo1 in iron metabolism, we generated mice with hepatocyte-specific deletion of Foxo1. These mice exhibited reduced hepatic hepcidin expression and serum hepcidin levels, accompanied by elevated serum iron and liver nonheme iron concentrations. Moreover, high-iron diet further exacerbated these abnormalities in iron metabolism in mice lacking hepatic Foxo1. Conversely, hepatocyte-specific Foxo1 overexpression increased hepatic hepcidin expression and serum hepcidin levels, thereby ameliorating iron overload in a murine model of hereditary hemochromatosis (Hfe-/- mice). In summary, our study identifies Foxo1 as a critical regulator of hepcidin and systemic iron homeostasis. Targeting Foxo1 may offer therapeutic opportunities for managing conditions associated with aberrant iron metabolism.

Alcohol-Associated Liver Disease Outcomes: Critical Mechanisms of Liver Injury Progression

Alcohol-associated liver disease (ALD) is a substantial cause of morbidity and mortality worldwide and represents a spectrum of liver injury beginning with hepatic steatosis (fatty liver) progressing to inflammation and culminating in cirrhosis. Multiple factors contribute to ALD progression and disease severity. Here, we overview several crucial mechanisms related to ALD end-stage outcome development, such as epigenetic changes, cell death, hemolysis, hepatic stellate cells activation, and hepatic fatty acid binding protein 4. Additionally, in this review, we also present two clinically relevant models using human precision-cut liver slices and hepatic organoids to examine ALD pathogenesis and progression.

Microglia nuclear receptor corepressor 1 deficiency alleviates neuroinflammation in mice

Given the established role of nuclear receptor corepressor 1 (NCoR1) in sensing environmental cues and the importance of inflammation in neurodegenerative diseases, elucidation of NCoR1 involvement in neuroinflammation has notable implications. Yet, its regulatory mechanism remains largely unclear. Under in vitro conditions, NCoR1 expression peaked and then decreased at 12 h after lipopolysaccharides (LPS) stimulation in BV2 cells, However, NCoR1 knockdown using si-RNA attenuated microglial inflammation, evident by reduced the levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), phosphorylated-JNK and high mobility group box-1 (HMGB1). Furthermore, NCoR1 suppression could counteract the decline in mitochondrial membrane potential while simultaneously enhancing the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). Under in vivo conditions, microglia-specific NCoR1 knockout (MNKO) mice after LPS injections alleviated the symptoms of anhedonia, diminished autonomic activity and cognitive impairment. Additionally, MNKO mice showed attenuation of microglial activation, downregulated HMGB1 and COX2, and upregulated PGC-1α expression in the cortex. In conclusion, these findings suggest that NCoR1 deficiency leads to a modest reduction in neuroinflammation, possibly attributed to the increased expression of PGC-1α.

Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander?

Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.

Ambiguous Pathogenic Roles of Macrophages in Alcohol-Associated Liver Diseases

Alcohol-associated liver disease (ALD) represents a major public health issue worldwide and is a leading etiology of liver cirrhosis. Alcohol-related liver injuries include a range of manifestations including alcoholic hepatitis (AH), simple steatosis, steatohepatitis, hepatic fibrosis, cirrhosis and liver cancer. Liver disease occurs from several pathological disturbances such as the metabolism of ethanol, which generates reactive oxygen species (ROS) in hepatocytes, alterations in the gut microbiota, and the immune response to these changes. A common hallmark of these liver affections is the establishment of an inflammatory environment, and some (broad) anti-inflammatory approaches are used to treat AH (eg, corticosteroids). Macrophages, which represent the main innate immune cells in the liver, respond to a wide variety of (pathogenic) stimuli and adopt a large spectrum of phenotypes. This translates to a diversity of functions including pathogen and debris clearance, recruitment of other immune cells, activation of fibroblasts, or tissue repair. Thus, macrophage populations play a crucial role in the course of ALD, but the underlying mechanisms driving macrophage polarization and their functionality in ALD are complex. In this review, we explore the various populations of hepatic macrophages in alcohol-associated liver disease and the underlying mechanisms driving their polarization. Additionally, we summarize the crosstalk between hepatic macrophages and other hepatic cell types in ALD, in order to support the exploration of targeted therapeutics by modulating macrophage polarization.

Orchestrated regulation of immune inflammation with cell therapy in pediatric acute liver injury

Acute liver injury (ALI) in children, which commonly leads to acute liver failure (ALF) with the need for liver transplantation, is a devastating life-threatening condition. As the orchestrated regulation of immune hemostasis in the liver is essential for resolving excess inflammation and promoting liver repair in a timely manner, in this study we focused on the immune inflammation and regulation with the functional involvement of both innate and adaptive immune cells in acute liver injury progression. In the context of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, it was also important to incorporate insights from the immunological perspective for the hepatic involvement with SARS-CoV-2 infection, as well as the acute severe hepatitis of unknown origin in children since it was first reported in March 2022. Furthermore, molecular crosstalk between immune cells concerning the roles of damage-associated molecular patterns (DAMPs) in triggering immune responses through different signaling pathways plays an essential role in the process of liver injury. In addition, we also focused on DAMPs such as high mobility group box 1 (HMGB1) and cold-inducible RNA-binding protein (CIRP), as well as on macrophage mitochondrial DNA-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway in liver injury. Our review also highlighted novel therapeutic approaches targeting molecular and cellular crosstalk and cell-based therapy, providing a future outlook for the treatment of acute liver injury.

Manganese Prussian blue nanozymes with antioxidant capacity prevent acetaminophen-induced acute liver injury

As one of the leading cases of acute liver failure triggered by excessive Acetaminophen (APAP), breakdown of the antioxidant system, inflammatory response, and inescapable apoptosis following overaccumulation of reactive oxygen species (ROS) play crucial roles in the mechanisms of APAP-induced liver injury (AILI). Therefore, cutting off ROS overproduction at the source is considered promising. Here, manganese Prussian blue nanozymes (MPBZs) with superior antioxidant enzyme-like activity are prepared as an effective strategy for hepatocyte protection, in which MPBZs accumulated in the liver show anti-oxidation properties by scavenging superfluous ROS. Importantly, in addition to alleviating oxidative stress, bioactive MPBZs with abundant variable valence states as a natural antioxidant enzymes mediated the responses of multi-biological signaling pathways in vitro and in vivo, including Nrf2-Keap1, NF-κB, and mitochondrial-induced apoptosis signaling pathways, enhancing tolerance for imminent AILI. Taking nanomedicine, hepatology, and catalytic chemistry into consideration, the revealed superior performance of AILI prevention suggests that MPBZ-based nano-detoxification therapy may offer an effective alternative against AILI.

PPARγ (Peroxisome Proliferator-Activated Receptor γ) Deacetylation Suppresses Aging-Associated Atherosclerosis and Hypercholesterolemia

BACKGROUND

Atherosclerosis is a medical urgency manifesting at the onset of hypercholesterolemia and is associated with aging. Activation of PPARγ (peroxisome proliferator-activated receptor γ) counteracts metabolic dysfunction influenced by aging, and its deacetylation displays an atheroprotective property. Despite the marked increase of PPARγ acetylation during aging, it is unknown whether PPARγ acetylation is a pathogenic contributor to aging-associated atherosclerosis.

METHODS

Mice with constitutive deacetylation-mimetic PPARγ mutations on lysine residues K268 and K293 (2KR) in an LDL (low-density lipoprotein)-receptor knockout (Ldlr-/-) background (2KR:Ldlr-/-) were aged for 18 months on a standard laboratory diet to examine the cardiometabolic phenotype, which was confirmed in Western-type diet-fed 2KR:Ldlr+/- mice. Whole-liver RNA-sequencing and in vitro studies in bone marrow-derived macrophages were conducted to decipher the mechanism.

RESULTS

In contrast to severe atherosclerosis in WT:Ldlr-/- mice, aged 2KR:Ldlr-/- mice developed little to no plaque, which was underlain by a significantly improved plasma lipid profile, with particular reductions in circulating LDL. The protection from hypercholesterolemia was recapitulated in Western-type diet-fed 2KR:Ldlr+/- mice. Liver RNA-sequencing analysis revealed suppression of liver inflammation rather than changes in cholesterol metabolism. This anti-inflammatory effect of 2KR was attributed to polarized M2 activation of macrophages. Additionally, the upregulation of core circadian component Bmal1 (brain and muscle ARNT-like 1), perceived to be involved in anti-inflammatory immunity, was observed in the liver and bone marrow-derived macrophages.

CONCLUSIONS

PPARγ deacetylation in mice prevents the development of aging-associated atherosclerosis and hypercholesterolemia, in association with the anti-inflammatory phenotype of 2KR macrophages.