High Mobility Group Box-1 Drives Fibrosis Progression Signaling via the Receptor for Advanced Glycation End Products in Mice

Activation of Sig-1R by afobazole attenuates Tollip/HMGB1-mediaded CCN2 autophagic degradation and NETs formation in sunitinib-induced cardiotoxicity in mice: Involvement of IRE 1α/ASK1/JNK/ AP-1 trajectory

Although the contribution of sigma1 receptor (Sig-1R) to afobazole's cardioprotection has been meticulously investigated, Sig-1R-mediated cardioprotective effect of afobazole against sunitinib cardiotoxicity has not been studied yet. Hence, we aimed at studying the potential modulatory impact of afobazole on Sig-1R to combat sunitinib-induced endoplasmic reticulum (ER) stress, maladaptive autophagy, and hyperactivation of neutrophils that ends up with neutrophil extracellular traps (NETs) formation. Pre-treatment with afobazole attenuated sunitinib-induced cardiotoxicity and enhanced cardiac function via significant reduction of TNNT2 and CK-MB, and restoration of nearly normal hemodynamic measurements. Afobazole-mediated Sig-1R activation mitigated the ER stress sensor, IRE1α activation and its downstream (ASK/JNK/AP-1) pathways along with caspase-3 and FK18. Subsequently, afobazole hindered NETs formation by prohibiting ER stress-induced activation of caspase-2 and pro-inflammatory cytokines; IL-1β and TNFα, as indicated by the significant reduction of NETs' specific components, namely, PAD4, NE, and MPO, along with the NETs' specific marker Cit H3. Afobazole also downregulated sunitinib-induced maladaptive autophagy, as reflected by reducing the expressions of autophagy-regulating proteins (ATG5 and ATG7) and microtubule-associated protein light chain 3 (LC3-II/I) ratio as well p62 upregulation. Furthermore, afobazole exhibited a cardioprotective effect by restoring nearly normal CCN2 level that was degraded by Tollip and HMGB1. The above-mentioned outcomes triggered by afobazole were clearly negated upon administration of the Sig-1R antagonist (BD1047), confirming that Sig-1R activation predominantly mediates the observed cardioprotective effects. Afobazole demonstrated efficacy in mitigating sunitinib-induced cardiotoxicity, as evidenced through the enhancements in hemodynamic stability, reduction of ER stress, amelioration of maladaptive autophagy, and inhibition of NETs formation.

QRICH1, as a key effector of endoplasmic reticulum stress, enhances HBV in promoting HMGB1 translocation and secretion in hepatocytes

BACKGROUND

Extracellular high mobility group box 1 (HMGB1) serves as a damage-associated molecular pattern (DAMP) and leads to diverse biological effects, including the aggravation of HBV-related liver diseases. However, mechanisms underlying HMGB1 secretion in HBV-induced hepatic injury and fibrosis remain unclear. Glutamine-rich 1 (QRICH1) is known as a critical effector of endoplasmic reticulum (ER) stress and is elevated in liver diseases. Whether QRICH1 participates in HBV-induced hepatic fibrosis warrants further investigation. Here, we explore the mechanism of HMGB1 secretion during HBV-induced hepatic fibrosis and the effect of QRICH1 on the process.

METHODS

In vivo experiments were conducted using a chronic recombinant cccDNA (rcccDNA) mouse model. Clinical specimens were obtained from Zhongshan Hospital, Fudan University. The levels of QRICH1 and HMGB1 were determined via immunohistochemistry. Liver collagen deposition was determined by Sirius red and Masson's trichrome staining. The serum levels of HMGB1 and indicators of liver injury were detected via ELISA. HMGB1 cyto-translocation was analyzed by Western blotting and quantitative real-time PCR (qRT-PCR).

RESULTS

Our findings demonstrated that ER stress promoted HBV-induced hepatic fibrosis in a mouse model. QRICH1 expression and HMGB1 secretion were elevated and positively correlated in rcccDNA mice with ER stress activation and chronic hepatitis B (CHB) patients with severe fibrosis. HBV modulated Sirtuin6 (SIRT6) expression, affecting HMGB1 cyto-translocation via acetylation regulation. Furthermore, QRICH1 enhanced HBV-induced HMGB1 translocation and secretion by regulating HMGB1 transcription.

CONCLUSION

HBV promotes HMGB1 acetylation and cyto-translocation by modulating SIRT6 expression. QRICH1 enhances HBV-induced HMGB1 translocation and secretion by regulating HMGB1 transcription.

RAGE deficiency ameliorates abdominal aortic aneurysm progression

BACKGROUND

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by inflammation and arterial wall degradation. The receptor for advanced glycation end products (RAGE) plays a pivotal role in regulating inflammatory pathways, but its specific contribution to AAA pathogenesis remains unclear.

PURPOSE

This study aimed to investigate the role of RAGE in AAA development by examining its expression in human and mice AAA tissues and exploring the effects of RAGE deficiency on aneurysm progression, macrophage polarization, and inflammatory responses.

METHODS

RAGE expression was analyzed in human AAA samples and porcine pancreatic elastase (PPE) induced AAA mouse models using Western blotting, immunohistochemistry, and immunofluorescence. In vivo RAGE-deficient (RAGE-/-) mice were generated to assess the impact of RAGE knockout on AAA progression. In vitro experiments utilized RAW264.7 transfected with RAGE-targeting siRNA to study macrophage polarization and NF-κB signaling.

RESULTS

RAGE expression was elevated in AAA tissues, particularly in macrophages. RAGE-/- mice exhibited reduced AAA incidence, mortality, and aortic dilation compared to wild-type mice. Histological analysis showed preserved elastic fibers and smooth muscle layers, along with decreased inflammatory cell infiltration and MMP2/MMP9 expression. RAGE deficiency inhibited M1-like macrophage polarization and pro-inflammatory cytokine secretion, mediated through suppression of the NF-κB pathway.

CONCLUSIONS

RAGE deficiency mitigates AAA progression by modulating macrophage polarization and reducing inflammation via the NF-κB pathway. These findings highlight RAGE as a potential therapeutic target for AAA treatment.

Neutrophil extracellular traps mediate pathophysiology of hepatic cells during liver injury

Neutrophil extracellular traps (NETs) are web-like, bactericidal structures produced by neutrophils and are composed principally of extracellular DNA, histones, elastase, and myeloperoxidase, among other components. NET formation is an innate immune response that is beneficial for pathogen killing and clearance. However, excessive NET formation and clearance defects can lead to inflammation and induce damage to host organs. NETs are also implicated in the development of noninfectious inflammatory disorders, such as liver injury in chronic liver diseases. The liver parenchyma contains hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, and hepatic stellate cells. Each of these cells possesses unique structures and functions, and their interactions with NETs result in pathophysiological changes contributing to liver injury. This review updates the findings related to the modes of action and molecular mechanisms by which NETs modulate the pathophysiology of various hepatic cells and potentiate liver injury. The article also reviews the roles of NETs in hepatic ischemia reperfusion injury, hepatocellular carcinoma pathogenesis, and cancer metastasis. Last, we examine data to determine whether NETs induce crosstalk among various hepatic cells during liver injury and to identify future research directions.

Extracellular vesicles from mesenchymal stem cells improve liver injury in rats with mild liver damage. Underlying mechanisms and role of TGFβ

Preventing the progression of liver damage to fibrosis would be beneficial for patients with steatotic liver disease (SLD). Mesenchymal stem cells (MSC) are a promising therapy for SLD and derived extracellular vesicles (EVs) could even improve the treatment's efficacy and safety. However, the mechanisms of MSC-EVs beneficial effects are not well known. It has been suggested that modifying the EVs cargo could improve their beneficial effects. The aims of this study were to assess if MSC-EVs reduce liver damage in a rat model of mild liver damage; to analyze the underlying mechanisms and to assess if silencing TGFβ enhances the beneficial effects of MSC-EVs. CCl4 was injected three times per week during four weeks to induce mild liver damage. EVs from human adipocyte MSC and from TGFβ-depleted MSC (siTGFβ-MSC-EVs) were injected in the tail vein. Steatosis, fibrosis, liver inflammation, macrophage infiltration and liver content of fibrotic markers, DAMPs, cytokines and bile acids were analyzed. Normal MSC-EVs reduce the CCL2 increase in liver, macrophage infiltration and the increases in the fibrosis markers collagen I and α-SMA. Treatment with siTGFβ-MSC-EVs, in addition, reduces liver steatosis, the increase of bile acids (mainly TCA), and DAMP HMGB1 levels, inducing a larger reduction of collagen I in liver of CCl4 rats. Treatment with MSCs-EVs effectively reduces early liver damage. Silencing of TGFβ in MSCs enhances the beneficial effects by additional mechanisms. Early treatment with MSC-EVs, especially after silencing TGFβ, could improve liver damage in SLD patients.

Ferroptosis: A New Strategy for the Treatment of Fibrotic Diseases

Ferroptosis is a new type of cell death characterized by iron dependence and the excessive accumulation of lipid reactive oxygen species (lipid ROS) that has gradually become better characterized. There is sufficient evidence indicating that ferroptosis is associated with a variety of human life activities and diseases, such as tumor suppression, ischemic organ injury, and degenerative disorders. Notably, ferroptosis is also involved in the initiation and development of fibrosis in various organs, including liver fibrosis, pulmonary fibrosis, renal fibrosis, and cardiac fibrosis, which is usually irreversible and refractory. Although a large number of patients with fibrosis urgently need to be treated, the current treatment options are still limited and unsatisfactory. Organ fibrosis involves a series of complex and orderly processes, such as parenchymal cell damage, recruitment of inflammatory cells and activation of fibroblasts, which ultimately leads to the accumulation of extracellular matrix (ECM) and the formation of fibrosis. An increasing number of studies have confirmed the close association between these pathological processes and ferroptosis. This review summarizes the role and function of ferroptosis in fibrosis and proposes several potential therapeutic strategies and pathways based on ferroptosis.

HMGB1 mediates epithelial-mesenchymal transition and fibrosis in silicosis via RAGE/β-catenin signaling

Epithelial-mesenchymal transition (EMT) is implicated in the pathogenesis of silicosis. High mobility group box 1 (HMGB1) has been found to induce EMT in fibrotic diseases. Previous studies have revealed a critical role of HMGB1 in silicosis, whereas the detail mechanisms still obscure. Here, we observed that HMGB1 protein was increased in the serum of silicosis patients and in the lung tissues of silicotic mice. The levels of HMGB1, receptor for advanced glycation end products (RAGE) and β-catenin protein were increased in the alveolar EMT cell model established by the treatment of transforming growth factor β1 (TGF-β1) and conditioned mediums derived from silica-stimulated macrophages. The activation of HMGB1, RAGE, β-catenin, EMT process, as well as cell migration triggered by TGF-β1 in RLE-6TN cells could be enhanced by treatment with recombinant HMGB1 protein (rHMGB1) and decreased by HMGB1 chemical inhibitor glycyrrhizin or RAGE inhibitor FPS-ZM1. And RAGE suppression could alleviate HMGB1-mediated the aggravation of β-catenin signaling, cell migration and EMT process induced by TGF-β1. Furthermore, both HMGB1 inhibition and RAGE knockout effectively alleviated the lung function impairment, EMT process, pulmonary inflammation and fibrosis in silicotic mice. These findings suggested that HMGB1 might promote EMT through RAGE/β-catenin axis in silicosis. And HMGB1 might constitute a therapeutic target for ameliorating the fibrosis of silicosis.

Bruceine A attenuates fibrogenesis and inflammation through NR2F2-regulated HMGB1 inflammatory signaling cascades in hepatic fibrosis

This investigation explored the hepatoprotective capabilities of Bruceine A (BA) and its underlying mechanisms in mitigating hepatic fibrosis. Hepatic stellate cells (HSCs) and mouse primary hepatocytes were treated with TGF-β and subsequently exposed to BA. To assess the effects of BA on the NR2F2-HMGB1 signaling cascade, these cells underwent transfection with a siRNA vector targeting NR2F2. The interaction between NR2F2 and the HMGB1 promoter was elucidated using a dual luciferase assay. In vivo, C57BL/6 mice were treated with thioacetamide (TAA) to induce liver damage, followed by administration of BA. The study found that BA moderated extracellular matrix (ECM) buildup, epithelial-mesenchymal transition (EMT), and inflammatory mediator levels, while concurrently reducing NR2F2 and HMGB1 expression in activated HSCs. Furthermore, BA lessened pyroptosis in hepatocytes, curtailing the inflammatory response. The absence of NR2F2 in HSCs or hepatocytes hindered BA's inhibitory effect on this pathway. It was demonstrated that NR2F2 binds directly to the HMGB1 promoter. Treatment with BA resulted in diminished serum levels of ALT and AST, mitigated damage in hepatic tissues, and decreased the ECM and neutrophil extracellular traps (NETs), thus protecting hepatocytes from fibrosis. Furthermore, BA suppressed the synthesis of inflammatory mediators such as NLRP3, caspase-1, and IL-1β by blocking the NR2F2-driven HMGB1 pathway, markedly reversing hepatic fibrosis. These observations highlight the efficacy of BA as a viable therapeutic candidate for hepatic fibrosis.

Emerging Roles of High-mobility Group Box-1 in Liver Disease

High-mobility group box-1 (HMGB1) is an architectural chromosomal protein with various roles depending on its cellular localization. Extracellular HMGB1 functions as a prototypical damage-associated molecular pattern that triggers inflammation and adaptive immune responses, mediated by specific cell surface receptors, including receptors for advanced glycation end products and toll-like receptors. Post-translational modifications of HMGB1 significantly impact various cellular processes that contribute to the pathogenesis of liver diseases. Recent studies have highlighted the close relationship between HMGB1 and the pathogenesis of acute liver injuries, including acetaminophen-induced liver injury, hepatic ischemia-reperfusion injury, and acute liver failure. In chronic liver diseases, HMGB1 plays a role in nonalcoholic fatty liver disease, alcohol-associated liver disease, liver fibrosis, and hepatocellular carcinoma. Targeting HMGB1 as a therapeutic approach, either by inhibiting its release or blocking its extracellular function, is a promising strategy for treating liver diseases. This review aimed to summarize the available evidence on HMGB1's role in liver disease, focusing on its multifaceted signaling pathways, impact on disease progression, and the translation of these findings into clinical interventions.

An anti-RAGE chimeric antibody alleviates CCl4-induced liver fibrosis via RAGE/NF-kB pathway in mice

Liver fibrosis is a progressive condition characterized by excessive deposition of extracellular matrix components, leading to organ dysfunction. Chronic inflammation and activation of hepatic stellate cells (HSCs) are two dominant events in all stages of fibrosis development. The receptor for advanced glycation end products (RAGE) pathway is involved in modulating liver injury and fibrosis, and preventing it, or deletion of Ager gene can protect the liver against fibrosis progression. To investigate functions and mechanism of chimeric anti-RAGE monoclonal antibody against liver fibrosis, murine-derived monoclonal anti-RAGE antibodies were used to construct murine-human chimeric antibodies. The properties of the chimeric antibody were characterized, and the biological functions of antibody A5 or its evolved humanized molecule, huA5, were investigated in cell or animal model. The data showed that blocking the RAGE pathway with huA5 robustly reduced liver injury and fibrosis. Furthermore, huA5 significantly suppressed the activation of HSCs and inhibited expression of fibrosis-associated genes, including COL1A1,TIMP1, and ACTA2. huA5 also interfered with RAGE downstream signal transduction and down-regulate both ERK and NF-κB phosphorylation, inhibited the RAGE/NF-kB pathway, leading to reduced expression of pro-inflammatory cytokines and profibrotic markers. Finally, RAGE silencing significantly decreased the expression of activation-related genes in HSCs, inhibiting HSCs proliferation and migration. These results clearly revealed that the anti-RAGE chimeric antibody exerted antifibrotic efficacy in vitro and attenuated liver fibrosis in vivo. HuA5 can be further developed as a lead molecule of drug to treat patients with liver fibrosis.

The role of macrophages in liver fibrosis: composition, heterogeneity, and therapeutic strategies

Macrophages, the predominant immune cells in the liver, are essential for maintaining hepatic homeostasis and responding to liver injury caused by external stressors. The hepatic macrophage population is highly heterogeneous and plastic, mainly comprised of hepatic resident kuffer cells (KCs), monocyte-derived macrophages (MoMφs), lipid-associated macrophages (LAMs), and liver capsular macrophages (LCMs). KCs, a population of resident macrophages, are localized in the liver and can self-renew through in situ proliferation. However, MoMφs in the liver are recruited from the periphery circulation. LAMs are a self-renewing subgroup of liver macrophages near the bile duct. While LCMs are located in the liver capsule and derived from peripheral monocytes. LAMs and LCMs are also involved in liver damage induced by various factors. Hepatic macrophages exhibit distinct phenotypes and functions depending on the specific microenvironment in the liver. KCs are critical for initiating inflammatory responses after sensing tissue damage, while the MoMφs infiltrated in the liver are implicated in both the progression and resolution of chronic hepatic inflammation and fibrosis. The regulatory function of liver macrophages in hepatic fibrosis has attracted significant interest in current research. Numerous literatures have documented that the MoMφs in the liver have a dual impact on the progression and resolution of liver fibrosis. The MoMφs in the liver can be categorized into two subtypes based on their Ly-6C expression level: inflammatory macrophages with high Ly-6C expression (referred to as Ly-6Chi subgroup macrophages) and reparative macrophages with low Ly-6C expression (referred to as Ly-6Clo subgroup macrophages). Ly-6Chi subgroup macrophages are conducive to the occurrence and progression of liver fibrosis, while Ly-6Clo subgroup macrophages are associated with the degradation of extracellular matrix (ECM) and regression of liver fibrosis. Given this, liver macrophages play a pivotal role in the occurrence, progression, and regression of liver fibrosis. Based on these studies, treatment therapies targeting liver macrophages are also being studied gradually. This review aims to summarize researches on the composition and origin of liver macrophages, the macrophage heterogeneity in the progression and regression of liver fibrosis, and anti-fibrosis therapeutic strategies targeting macrophages in the liver.

Identification of protein partners for small molecules reshapes the understanding of nonalcoholic steatohepatitis and drug discovery

AIMS

Nonalcoholic steatohepatitis (NASH) is the severe subtype of nonalcoholic fatty diseases (NAFLD) with few options for treatment. Patients with NASH exhibit partial responses to the current therapeutics and adverse effects. Identification of the binding proteins for the drugs is essential to understanding the mechanism and adverse effects of the drugs and fuels the discovery of potent and safe drugs. This paper aims to critically discuss recent advances in covalent and noncovalent approaches for identifying binding proteins that mediate NASH progression, along with an in-depth analysis of the mechanisms by which these targets regulate NASH.

MATERIALS AND METHODS

A literature search was conducted to identify the relevant studies in the database of PubMed and the American Chemical Society. The search covered articles published from January 1990 to July 2024, using the search terms with keywords such as NASH, benzophenone, diazirine, photo-affinity labeling, thermal protein profiling, CETSA, target identification.

KEY FINDINGS

The covalent approaches utilize drugs modified with diazirine and benzophenone to covalently crosslink with the target proteins, which facilitates the purification and identification of target proteins. In addition, they map the binding sites in the target proteins. By contrast, noncovalent approaches identify the binding targets of unmodified drugs in the intact cell proteome. The advantages and limitations of both approaches have been compared, along with a comprehensive analysis of recent innovations that further enhance the efficiency and specificity.

SIGNIFICANCE

The analyses of the applicability of these approaches provide novel tools to delineate NASH pathogenesis and promote drug discovery.

Post-translational modifications drive the effects of HMGB1 in alcohol-associated liver disease

BACKGROUND

We previously identified that high-mobility group box-1 (HMGB1) is increased and undergoes post-translational modifications (PTMs) in response to alcohol consumption. Here, we hypothesized that specific PTMs, occurring mostly in hepatocytes and myeloid cells, could contribute to the pathogenesis of alcohol-associated liver disease (AALD).

METHODS

We used the Lieber-DeCarli (LD) model of early alcohol-induced liver injury, combined with engineered viral vectors and genetic approaches to regulate the expression of HMGB1, its PTMs (reduced [H], oxidized [O], acetylated [Ac], both [O + Ac]), and its receptors (RAGE, TLR4) in a cell-specific manner (hepatocytes and/or myeloid cells).

RESULTS

Hmgb1 ablation in hepatocytes or myeloid cells partially protected, while ablation in both prevented steatosis, inflammation, IL1B production, and alcohol-induced liver injury. Hepatocytes were a major source of [H], [O], and [Ac] HMGB1, whereas myeloid cells produced only [H] and [Ac] HMGB1. Neutralization of HMGB1 prevented, whereas injection of [H] HMGB1 increased AALD, which was worsened by injection of [O] HMGB1. While [O] HMGB1 induced liver injury, [Ac] HMGB1 protected and counteracted the effects of [O] HMGB1 in AALD. [O] HMGB1 stimulated macrophage (MF) migration, activation, IL1B production, and secretion. Ethanol-fed RageΔMye but not Tlr4ΔMye, RageΔHep, or Tlr4ΔHep mice were protected from AALD, indicating a crucial role of RAGE in myeloid cells for AALD. [O] HMGB1 recruited and activated myeloid cells through RAGE and contributed to steatosis, inflammation, and IL1B production in AALD.

CONCLUSIONS

These results provide evidence for targeting [O] HMGB1 of hepatocyte origin as a ligand for RAGE signaling in myeloid cells and a driver of steatosis, inflammatory cell infiltration, and IL1B production in AALD. Importantly, we reveal that [Ac] HMGB1 offsets the noxious effects of [O] HMGB1 in AALD.

Hepatocyte activation and liver injury following cerebral ischemia promote HMGB1-mediated hepcidin upregulation in hepatocytes and regulation of systemic iron levels

We previously reported that high mobility group box 1 (HMGB1), a danger-associated molecular pattern (DAMP), increases intracellular iron levels in the postischemic brain by upregulating hepcidin, a key regulator of iron homeostasis, triggering ferroptosis. Since hepatocytes are the primary cells that produce hepcidin and control systemic iron levels, we investigated whether cerebral ischemia induces hepcidin upregulation in hepatocytes. Following middle cerebral artery occlusion (MCAO) in a rodent model, significant liver injury was observed. This injury was evidenced by significantly elevated Eckhoff's scores and increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Additionally, total iron levels were significantly elevated in the liver, with intracellular iron accumulation detected in hepatocytes. Hepcidin expression in the liver, which is primarily localized in hepatocytes, increased significantly starting at 3 h after MCAO and continued to increase rapidly, reaching a peak at 24 h. Interestingly, HMGB1 levels in the liver were also significantly elevated after MCAO, with the disulfide form of HMGB1 being the major subtype. In vitro experiments using AML12 hepatocytes showed that recombinant disulfide HMGB1 significantly upregulated hepcidin expression in a Toll-like receptor 4 (TLR4)- and RAGE-dependent manner. Furthermore, treatment with a ROS scavenger and a peptide HMGB1 antagonist revealed that both ROS generation and HMGB1 induction contributed to hepatocyte activation and liver damage following MCAO-reperfusion. In conclusion, this study revealed that cerebral ischemia triggers hepatocyte activation and liver injury. HMGB1 potently induces hepcidin not only in the brain but also in the liver, thereby influencing systemic iron homeostasis following ischemic stroke.

Nano-drug delivery systems (NDDS) in metabolic dysfunction-associated steatotic liver disease (MASLD): current status, prospects and challenges

About one-third of the global population suffers from metabolic dysfunction-associated steatotic liver disease (MASLD), but specific treatments for MASLD have long been lacking, primarily due to the unclear etiology of the disease. In addition to lifestyle modifications and weight loss surgery, pharmacotherapy is the most common treatment among MASLD patients, and these drugs typically target the pathogenic factors of MASLD. However, bioavailability, efficacy, and side effects all limit the maximum therapeutic potential of the drugs. With the development of nanomedicine, recent years have seen attempts to combine MASLD pharmacotherapy with nanomaterials, such as liposomes, polymer nanoparticles, micelles, and cocrystals, which effectively improves the water solubility and targeting of the drugs, thereby enhancing therapeutic efficacy and reducing toxic side effects, offering new perspectives and futures for the treatment of MASLD.

Nanoformulations for the diagnosis and treatment of metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive phase of metabolic dysfunction-associated steatotic liver disease (MASLD) that develops into irreversible liver cirrhosis and hepatocellular carcinoma, ultimately necessitating liver transplantation as the sole life-saving option. However, given the drawbacks of liver transplantation, including invasiveness, chronic immunosuppression, and a lack of donor livers, prompt diagnosis and effective treatment are indispensable. Due to the limitations of liver biopsy and conventional imaging modalities in diagnosing MASH, as well as the potential hazards associated with liver-protecting medicines, numerous nanoformulations have been created for MASH theranostics. Particularly, there has been significant study interest in artificial nanoparticles, natural biomaterials, and bionic nanoparticles that exhibit exceptional biocompatibility and bioavailability. In this review, we summarized extracellular vesicles (EVs)-based omics analysis and Fe3O4-based functional magnetic nanoparticles as magnetic resonance imaging (MRI) contrast agents for MASH diagnosis. Additionally, artificial nanoparticles such as organic and inorganic nanoparticles, as well as natural biomaterials such as cells and cell-derived EVs and bionic nanoparticles including cell membrane-coated nanoparticles, have also been reported for MASH treatment owing to their specific targeting and superior therapeutic effect. This review has the potential to stimulate advancements in nanoformulation fabrication techniques. By exploring their compatibility with cell biology, it could lead to the creation of innovative material systems for efficient theragnostic uses for MASH. STATEMENT OF SIGNIFICANCE: People with metabolic dysfunction-associated steatohepatitis (MASH) will progress to fibrosis, cirrhosis, or even liver cancer. It is imperative to establish effective theragnostic techniques to stop MASH from progressing into a lethal condition. In our review, we summarize the advancement of artificial, natural, and bionic nanoparticles applied in MASH theragnosis. Furthermore, the issues that need to be resolved for these cutting-edge techniques are summarized to realize a more significant clinical impact. We forecast the key fields that will advance further as nanotechnology and MASH research progress. Generally, our discovery has significant implications for the advancement of nanoformulation fabrication techniques, and their potential to be compatible with cell biology could lead to the creation of innovative materials systems for effective MASH theragnostic.

RG-I pectin-like polysaccharide from Rosa chinensis inhibits inflammation and fibrosis associated to HMGB1/TLR4/NF-κB signaling pathway to improve non-alcoholic steatohepatitis

A novel RG-I pectin-like polysaccharide, YJ3A1, was purified from the flowers of Rosa chinensis and its structure and hepatoprotective effect in vivo and in vitro were investigated. The backbone of this polysaccharide is mainly composed of 1, 4-galactan, 1, 4-linked α-GalpA and 1, 2-linked α-Rhap disaccharide repeating unit attached by 1, 6-linked β-Galp or 1, 5-linked α-Araf on C-4 of the Rhap. Interestingly, oral administration of YJ3A1 significantly ameliorates NASH-associated inflammation, oxidative stress and fibrosis and does not affect the liver morphology of normal mice at a dose of 50 mg/kg. The mechanism study suggests that the biological activity may associate to inactivating of high-mobility group box 1 protein (HMGB1)/TLR4/NF-κB and Akt signaling pathways by restraining the expression and release of HMGB1, thereby impeding the effect of NASH. The current findings outline a novel leading polysaccharide for new drug candidate development against NASH.

HMGB1 as an extracellular pro-inflammatory cytokine: Implications for drug-induced organic damage

Drug-induced organic damage encompasses various intricate mechanisms, wherein HMGB1, a non-histone chromosome-binding protein, assumes a significant role as a pivotal hub gene. The regulatory functions of HMGB1 within the nucleus and extracellular milieu are interlinked. HMGB1 exerts a crucial regulatory influence on key biological processes including cell survival, inflammatory regulation, and immune response. HMGB1 can be released extracellularly from the cell during these processes, where it functions as a pro-inflammation cytokine. HMGB1 interacts with multiple cell membrane receptors, primarily Toll-like receptors (TLRs) and receptor for advanced glycation end products (RAGE), to stimulate immune cells and trigger inflammatory response. The excessive or uncontrolled HMGB1 release leads to heightened inflammatory responses and cellular demise, instigating inflammatory damage or exacerbating inflammation and cellular demise in different diseases. Therefore, a thorough review on the significance of HMGB1 in drug-induced organic damage is highly important for the advancement of pharmaceuticals, ensuring their effectiveness and safety in treating inflammation as well as immune-related diseases. In this review, we initially outline the characteristics and functions of HMGB1, emphasizing their relevance in disease pathology. Then, we comprehensively summarize the prospect of HMGB1 as a promising therapeutic target for treating drug-induced toxicity. Lastly, we discuss major challenges and propose potential avenues for advancing the development of HMGB1-based therapeutics.

Hepatocyte-specific loss of DDB1 attenuates hepatic steatosis but aggravates liver inflammation and fibrosis in MASH

BACKGROUND

MASH is a common clinical disease that can lead to advanced liver conditions, but no approved pharmacotherapies are available due to an incomplete understanding of its pathogenesis. Damaged DNA binding protein 1 (DDB1) participates in lipid metabolism. Nevertheless, the function of DDB1 in MASH is unclear.

METHODS

Clinical liver samples were obtained from patients with MASH and control individuals by liver biopsy. Hepatocyte-specific Ddb1-knockout mice and liver Hmgb1 knockdown mice were fed with a methionine-and choline-deficient diet to induce MASH.

RESULTS

We found that the expression of DDB1 in the liver was significantly decreased in MASH models. Hepatocyte-specific ablation of DDB1 markedly alleviated methionine-and choline-deficient diet-induced liver steatosis but unexpectedly exacerbated inflammation and fibrosis. Mechanistically, DDB1 deficiency attenuated hepatic steatosis by downregulating the expression of lipid synthesis and uptake genes. We identified high-mobility group box 1 as a key candidate target for DDB1-mediated liver injury. DDB1 deficiency upregulated the expression and extracellular release of high-mobility group box 1, which further increased macrophage infiltration and activated HSCs, ultimately leading to the exacerbation of liver inflammation and fibrosis.

CONCLUSIONS

These data demonstrate the independent regulation of hepatic steatosis and injury in MASH. These findings have considerable clinical implications for the development of therapeutic strategies for MASH.

Sex-determining region Y gene promotes liver fibrosis and accounts for sexual dimorphism in its pathophysiology

BACKGROUND & AIMS

Men are more prone to develop and die from liver fibrosis than women. In this study, we aim to investigate how sex-determining region Y gene (SRY) in hepatocytes promotes liver fibrosis.

METHODS

Hepatocyte-specific Sry knock-in (KI), Sry knockout (KO), and Sry KI with platelet-derived growth factor receptor α (Pdgfrα) KO mice were generated. Liver fibrosis was induced in mice by bile duct ligation for 2 weeks or carbon tetrachloride treatment for 6 weeks. In addition, primary hepatocytes, hepatic stellate cells (HSCs), and immortalized cell lines were used for in vitro studies and mechanistic investigation.

RESULTS

Compared to females, the severity of toxin- or cholestasis-induced liver fibrosis is similarly increased in castrated and uncastrated male mice. Among all Y chromosome-encoded genes, SRY was the most significantly upregulated and consistently increased gene in fibrotic/cirrhotic livers in male patients and in mouse models. Sry KI mice developed exacerbated liver fibrosis, whereas Sry KO mice had alleviated liver fibrosis, compared to age- and sex-matched control mice after bile duct ligation or administration of carbon tetrachloride. Mechanistically, both our in vivo and in vitro studies illustrated that SRY in hepatocytes can transcriptionally regulate Pdgfrα expression, and promote HMGB1 (high mobility group box 1) release and subsequent HSC activation. Pdgfrα KO or treatment with the SRY inhibitor DAX1 in Sry KI mice abolished SRY-induced HMGB1 secretion and liver fibrosis.

CONCLUSIONS

SRY is a strong pro-fibrotic factor and accounts for the sex disparity observed in liver fibrosis, suggesting its critical role as a potentially sex-specific therapeutic target for prevention and treatment of the disease.

IMPACT AND IMPLICATION

We identified that a male-specific gene, sex-determining region Y gene (SRY), is a strong pro-fibrotic gene that accounts for the sex disparity observed in liver fibrosis. As such, SRY might be an appropriate target for surveillance and treatment of liver fibrosis in a sex-specific manner. Additionally, SRY might be a key player in the sexual dimorphism observed in hepatic pathophysiology more generally.

The inhibitory effects of endophytic metabolites on glycated proteins under non-communicable disease conditions: A review

Protein glycation in human body is closely linked to the onset/progression of diabetes associated complications. These glycated proteins are commonly known as advanced glycation end products (AGEs). Recent literature has also highlighted the involvement of AGEs in other non-communicable diseases (NCDs) such as cardiovascular, cancer, and Alzheimer's diseases and explored the impact of plant metabolites on AGEs formation. However, the significance of endophytic metabolites against AGEs has recently garnered attention but has not been thoroughly summarized thus far. Therefore, the objective of this review is to provide a comprehensive overview of the importance of endophytic metabolites in combating AGEs under NCDs conditions. Additionally, this review aims to elucidate the processes of AGEs formation, absorption, metabolism, and their harmful effects. Collectively, endophytic metabolites play a crucial role in modulating signaling pathways and enhancing the digestibility properties of gut microbiota (GM) by targeting on AGEs/RAGE (receptor for AGEs) axis. Furthermore, these metabolites exhibit anti-AGEs activities similar to those derived from host plants, but at a lower cost and higher production rate. The use of endophytes as a source of such metabolites offers a risk-free and sustainable approach that holds substantial potential for the treatment and management of NCDs.

Neutrophil extracellular traps (NETs) and fibrotic diseases

Fibrosis, a common cause and serious outcome of organ failure that can affect any organ, is responsible for up to 45% of all deaths in various clinical settings. Both preclinical models and clinical trials investigating various organ systems have shown that fibrosis is a highly dynamic process. Although many studies have sought to gain understanding of the mechanism of fibrosis progression, their findings have been mixed. In recent years, increasing evidence indicates that neutrophil extracellular traps (NETs) are involved in many inflammatory and autoimmune disorders and participate in the regulation of fibrotic processes in various organs and systems. In this review, we summarize the current understanding of the role of NETs in fibrosis development and progression and their possibility as therapeutic targets.

A Protein Complex of Liver Origin Activates a Pro-inflammatory Program That Drives Hepatic and Intestinal Injury in Alcohol-Associated Liver Disease

BACKGROUND & AIMS

There is limited information on how the liver-to-gut axis contributes to alcohol-associated liver disease (AALD). We previously identified that high-mobility group box-1 (HMGB1) undergoes oxidation in hepatocytes and demonstrated elevated serum levels of oxidized HMGB1 ([O] HMGB1) in alcoholic patients. Since interleukin-1 beta (IL-1B) increases in AALD, we hypothesized hepatocyte-derived [O] HMGB1 could interact with IL-1B to activate a pro-inflammatory program that, besides being detrimental to the liver, drives intestinal barrier dysfunction.

RESULTS

Alcohol-fed RageΔMye mice exhibited decreased nuclear factor kappa B signaling, a pro-inflammatory signature, and reduced total intestinal permeability, resulting in protection from AALD. In addition, [O] HMGB1 bound and signaled through the receptor for advanced-glycation end-products (RAGE) in myeloid cells, driving hepatic inflammation, intestinal permeability, and increased portal blood lipopolysaccharide in AALD. We identified that [O] HMGB1 formed a complex with IL-1B, which was found in the livers of patients with acute alcoholic hepatitis and mice with AALD. This complex originated from the liver, because it was absent in the intestine when hepatocytes did not produce [O] HMGB1. Mechanistically, the complex bound RAGE in Kupffer cells and macrophages induced a pro-inflammatory program. Moreover, it bound RAGE in intestinal macrophages and epithelial cells, leading to intestinal inflammation, altered intestinal epithelial cell tight junction protein expression, increased intestinal permeability, and elevated portal blood lipopolysaccharide, enhancing AALD pathogenesis.

CONCLUSIONS

We identified a protein complex of liver origin that amplifies the pro-inflammatory feedback loop in AALD; therefore, targeting this complex could have significant therapeutic potential.

Glycyrrhizic Acid Alleviates Semen Strychni-Induced Neurotoxicity Through the Inhibition of HMGB1 Phosphorylation and Inflammatory Responses

The neurotoxicity of Semen Strychni has been reported recently in several clinical cases. Therefore, this study was conducted to investigate the role of HMGB1 in a model of neurotoxicity induced by Semen Strychni and to assess the potential alleviating effects of glycyrrhizic acid (GA), which is associated with the regulation of HMGB1 release. Forty-eight SD rats were intraperitoneally injected with Semen Strychni extract (175 mg/kg), followed by oral administration of GA (50 mg/kg) for four days. After treatment of SS and GA, neuronal degeneration, apoptosis, and necrosis were observed via histopathological examination. Inflammatory cytokines (TNF-α and IL-1β), neurotransmitter associated enzymes (MAO and AChE), serum HMGB1, nuclear and cytoplasmic HMGB1/ph-HMGB1, and the interaction between PP2A, PKC, and HMGB1 were evaluated. The influence of the MAPK pathway was also examined. As a result, this neurotoxicity was characterized by neuronal degeneration and apoptosis, the induction of pro-inflammatory cytokines, and a reduction in neurotransmitter-metabolizing enzymes. In contrast, GA treatment significantly ameliorated the abovementioned effects and alleviated nerve injury. Furthermore, Semen Strychni promoted HMGB1 phosphorylation and its translocation between the nucleus and cytoplasm, thereby activating the NF-κB and MAPK pathways, initiating various inflammatory responses. Our experiments demonstrated that GA could partially reverse these effects. In summary, GA acid alleviated Semen Strychni-induced neurotoxicity, possibly by inhibiting HMGB1 phosphorylation and preventing its release from the cell.

Transcriptomic and proteomic investigation of the ameliorative effect of total polyphenolic glycoside extract on hepatic fibrosis in Lamiophlomis rotata Kudo via the AGE/RAGE pathway

ETHNOPHARMACOLOGICAL RELEVANCE

During the regression of liver fibrosis, a decrease in hepatic stellate cells (HSCs) can occur through apoptosis or inactivation of activated HSCs (aHSCs). A new approach for antifibrotic therapy involves transforming hepatic myofibroblasts into a quiescent-like state. Lamiophlomis rotata (Benth.) Kudo (L. rotata), an orally available Tibetan herb, has traditionally been used to treat skin disease, jaundice, and rheumatism. In our previous study, we found that the total polyphenolic glycoside extract of L. rotata (TPLR) promotes apoptosis in aHSCs for the treatment of hepatic fibrosis. However, whether TPLR induces aHSCs to become inactivated HSCs (iHSCs) is unclear, and the underlying mechanism remains largely unknown.

PURPOSE

This study aimed to examine the impact of TPLR on the phenotypes of hepatic stellate cells (HSCs) during the regression of liver fibrosis and explore the potential mechanism of action.

METHODS

The effect of TPLR on the phenotypes of hepatic stellate cells (HSCs) was assessed using immunofluorescence (IF) staining, reverse transcription-polymerase chain reaction (RT-PCR), and Western blotting. Transcriptomic and proteomic methods were employed to identify the main signaling pathways involved. Based on the omics results, the likely mechanism of TPLR on the phenotypes of aHSCs was confirmed through overexpression and knockdown experiments in TGF-β1-activated LX-2 cells. Using a CCl4-induced liver fibrosis mouse model, we evaluated the anti-hepatic fibrosis effect of TPLR and explored its potential mechanism based on omics findings.

RESULTS

TPLR was found to induce the differentiation of aHSCs into iHSCs by significantly decreasing the protein expression of α-SMA and Desmin. Transcriptomic and proteomic analyses revealed that the AGE/RAGE signaling pathway plays a crucial role in the morphological transformation of HSCs following TPLR treatment. In vitro experiments using RAGE overexpression and knockdown demonstrated that the mechanism by which TPLR affects the phenotype of HSCs is closely associated with the RAGE/RAS/MAPK/NF-κB axis. In a model of liver fibrosis, TPLR obviously inhibited the generation of AGEs and alleviated liver tissue damage and fibrosis by downregulating RAGE and its downstream targets.

CONCLUSION

The AGE/RAGE axis plays a pivotal role in the transformation of activated hepatic stellate cells (aHSCs) into inactivated hepatic stellate cells (iHSCs) following TPLR treatment, indicating the potential of TPLR as a therapeutic agent for the management of liver fibrosis.

Predictors of liver disease progression in people living with HIV-HBV co-infection on antiretroviral therapy

BACKGROUND

In people living with HIV-HBV, liver fibrosis progression can occur even with suppressive antiretroviral therapy (ART). We investigated the relationship between liver fibrosis and biomarkers of inflammation, apoptosis, and microbial translocation.

METHODS

In this observational cohort study adults living with HIV-HBV already on effective ART were recruited in Australia and Thailand and followed for 3 years including 6 monthly clinical review and blood tests and annual transient elastography. Differences in clinical and laboratory predictors of liver fibrosis progression were tested followed by regression analysis adjusted for CD4+ T-cells at study entry. A linear mixed model was fitted to longitudinal data to explore changes over time.

FINDINGS

67 participants (85% male, median age 49 y) were followed for 175 person-years. Median duration of ART was 10 years (interquartile range (IQR) 8-16 years). We found 11/59 (19%) participants during 3-years follow-up (6/100 person-years) met the primary endpoint of liver disease progression, defined as increased Metavir stage from baseline to final scan. In regression analysis, progressors compared to non-progressors had higher levels of high mobility group box 1 protein (HGMB1), (median (IQR) 3.7 (2.6-5.0) and 2.4 ng/mL (1.5-3.4) respectively, adjusted relative risk 1.47, 95% CI [1.00, 2.17]) and lower nadir CD4+ T-cell percentage (median 4% (IQR 2-8) and 11% (4-15) respectively (relative risk 0.93, 95% CI [0.88, 0.98]).

INTERPRETATION

Progression in liver fibrosis occurs in people with HIV-HBV on suppressive ART. Fibrosis progression was associated with higher HMGB1 and lower percentage nadir CD4+ T-cell count, highlighting the importance of early initiation of HBV-active ART.

FUNDING

This work was supported by NHMRC project grant 1101836; NHMRC practitioner fellowship 1138581 and NHMRC program grant 1149990. The funder had no role in study design, data collection, data analysis, interpretation, writing of this manuscript or decision to submit for publication.

Total iridoid glycoside extract of Lamiophlomis rotata (Benth) Kudo accelerates diabetic wound healing by the NRF2/COX2 axis

BACKGROUND

Lamiophlomis rotata (Benth.) Kudo (L. rotata), the oral Traditional Tibetan herbal medicine, is adopted for treating knife and gun wounds for a long time. As previously demonstrated, total iridoid glycoside extract of L. rotata (IGLR) induced polarization of M2 macrophage to speed up wound healing. In diabetic wounds, high levels inflammatory and chemotactic factors are usually related to high reactive oxygen species (ROS) levels. As a ROS target gene, nuclear factor erythroid 2-related factor 2 (NRF2), influences the differentiation of monocytes to M1/M2 macrophages. Fortunately, iridoid glycosides are naturally occurring active compounds that can be used as the oxygen radical scavenger. Nevertheless, the influence of IGLR in diabetic wound healing and its associated mechanism is largely unclear.

MATERIALS AND METHODS

With macrophages and dermal fibroblasts in vitro, as well as a thickness excision model of db/db mouse in vivo, the role of IGLR in diabetic wound healing and the probable mechanism of the action were investigated.

RESULTS

Our results showed that IGLR suppressed oxidative distress and inflammation partly through the NRF2/cyclooxygenase2 (COX2) signaling pathway in vitro. The intercellular communication between macrophages and dermal fibroblasts was investigated by the conditioned medium (CM) of IGLR treatment cells. The CM increased the transcription and translation of collagen I (COL1A1) and alpha smooth muscle actin (α-SMA) within fibroblasts. With diabetic wound mice, the data demonstrated IGLR activated the NRF2/KEAP1 signaling and the downstream targets of the pathway, inhibited COX2/PEG2 signaling and decreased the interaction inflammatory targets of the axis, like interleukin-1beta (IL-1β), interleukin 6 (IL-6), apoptosis-associated speck-like protein (ASC), cysteinyl aspartate specific proteinase1 (caspase1) and NOD-like receptor-containing protein 3 (NLRP3).In addition, the deposition of COL1A1, and the level of α-SMA, and Transforming growth factor-β1 (TGF-β1) obviously elevated, whereas that of pro-inflammatory factors reduced in the diabetic wound tissue with IGLR treatment.

CONCLUSION

IGLR suppressed oxidative distress and inflammation mainly through NRF2/COX2 axis, thus promoting paracrine and accelerating wound healing in diabetes mice.

Redox-sensitive high-mobility group box-1 isoforms contribute to liver fibrosis progression and resolution in mice

BACKGROUND & AIMS

High-mobility group box-1 (HMGB1) significantly increases and undergoes post-translational modifications (PTMs) in response to liver injury. Since oxidative stress plays a major role in liver fibrosis and induces PTMs in proteins, we hypothesized that redox-sensitive HMGB1 isoforms contribute to liver fibrosis progression and resolution.

METHODS

We used ESI-LC-MS (electrospray ionization-liquid chromatography-mass spectrometry) to study PTMs of HMGB1 during fibrosis progression and resolution. Conditional knockout mice were used for functional analyses.

RESULTS

We identified that disulfide ([O]) and sulfonated ([SO3]) HMGB1 increase during carbon tetrachloride-induced liver fibrosis progression, however, while [O] HMGB1 declines, [SO3] HMGB1 drops but remains, during fibrosis resolution. Conditional knockout of Hmgb1 revealed that production of [O] and [SO3] HMGB1 occurs mostly in hepatocytes. Co-injection of [O] HMGB1 worsens carbon tetrachloride-induced liver fibrosis more than co-injection of [H] HMGB1. Conversely, ablation of [O] Hmgb1 in hepatocytes reduces liver fibrosis. Moreover, ablation of the receptor for advanced-glycation end-products (Rage) reveals that the profibrogenic effect of [O] HMGB1 is mediated by RAGE signaling in hepatic stellate cells (HSCs). Notably, injection of [SO3] HMGB1 accelerates fibrosis resolution due to RAGE-dependent stimulation of HSC apoptosis. Importantly, gene signatures activated by redox-sensitive HMGB1 isoforms in mice, classify patients with fibrosis according to fibrosis and inflammation scores.

CONCLUSION

Dynamic changes in hepatocyte-derived [O] and [SO3] HMGB1 signal through RAGE-dependent mechanisms on HSCs to drive their profibrogenic phenotype and fate, contributing to progression and resolution of liver fibrosis.

IMPACT AND IMPLICATIONS

Since oxidative stress plays a major role in liver fibrosis and induces post-translational modifications of proteins, we hypothesized that redox-sensitive HMGB1 isoforms contribute to liver fibrosis progression and resolution. This study is significant because a rise in [H] HMGB1 could flag 'patient at risk', the presence of [O] HMGB1 could suggest 'disease in progress or active scarring', while the appearance of [SO3] HMGB1 could point at 'resolution under way'. The latter could be used as a readout for response to pharmacological intervention with anti-fibrotic agents.

A patent review on HMGB1 inhibitors for the treatment of liver diseases

INTRODUCTION

HMGB1 is a non-histone chromatin protein released or secreted in response to tissue damage or infection. Extracellular HMGB1, as a crucial immunomodulatory factor, binds with several different receptors to innate inflammatory responses that aggravate acute and chronic liver diseases. The increased levels of HMGB1 have been reported in various liver diseases, highlighting that it represents a potential biomarker and druggable target for therapeutic development.

AREAS COVERED

This review summarizes the current knowledge on the structure, function, and interacting receptors of HMGB1 and its significance in multiple liver diseases. The latest patented and preclinical studies of HMGB1 inhibitors (antibodies, peptides, and small molecules) for liver diseases are summarized by using the keywords 'HMGB1,' 'HMGB1 antagonist, HMGB1-inhibitor,' 'liver disease' in Web of Science, Google Scholar, Google Patents, and PubMed databases in the year from 2017 to 2023.

EXPERT OPINIONS

In recent years, extensive research on HMGB1-dependent inflammatory signaling has discovered potent inhibitors of HMGB1 to reduce the severity of liver injury. Despite significant progress in the development of HMGB1 antagonists, few of them are approved for clinical treatment of liver-related diseases. Developing safe and effective specific inhibitors for different HMGB1 isoforms and their interaction with receptors is the focus of future research.

Contributing roles of mitochondrial dysfunction and hepatocyte apoptosis in liver diseases through oxidative stress, post-translational modifications, inflammation, and intestinal barrier dysfunction

This review provides an update on recent findings from basic, translational, and clinical studies on the molecular mechanisms of mitochondrial dysfunction and apoptosis of hepatocytes in multiple liver diseases, including but not limited to alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and drug-induced liver injury (DILI). While the ethanol-inducible cytochrome P450-2E1 (CYP2E1) is mainly responsible for oxidizing binge alcohol via the microsomal ethanol oxidizing system, it is also responsible for metabolizing many xenobiotics, including pollutants, chemicals, drugs, and specific diets abundant in n-6 fatty acids, into toxic metabolites in many organs, including the liver, causing pathological insults through organelles such as mitochondria and endoplasmic reticula. Oxidative imbalances (oxidative stress) in mitochondria promote the covalent modifications of lipids, proteins, and nucleic acids through enzymatic and non-enzymatic mechanisms. Excessive changes stimulate various post-translational modifications (PTMs) of mitochondrial proteins, transcription factors, and histones. Increased PTMs of mitochondrial proteins inactivate many enzymes involved in the reduction of oxidative species, fatty acid metabolism, and mitophagy pathways, leading to mitochondrial dysfunction, energy depletion, and apoptosis. Unique from other organelles, mitochondria control many signaling cascades involved in bioenergetics (fat metabolism), inflammation, and apoptosis/necrosis of hepatocytes. When mitochondrial homeostasis is shifted, these pathways become altered or shut down, likely contributing to the death of hepatocytes with activation of inflammation and hepatic stellate cells, causing liver fibrosis and cirrhosis. This review will encapsulate how mitochondrial dysfunction contributes to hepatocyte apoptosis in several types of liver diseases in order to provide recommendations for targeted therapeutics.

Emerging delivery approaches for targeted pulmonary fibrosis treatment

Pulmonary fibrosis (PF) is a progressive, and life-threatening interstitial lung disease which causes scarring in the lung parenchyma and thereby affects architecture and functioning of lung. It is an irreversible damage to lung functioning which is related to epithelial cell injury, immense accumulation of immune cells and inflammatory cytokines, and irregular recruitment of extracellular matrix. The inflammatory cytokines trigger the differentiation of fibroblasts into activated fibroblasts, also known as myofibroblasts, which further increase the production and deposition of collagen at the injury sites in the lung. Despite the significant morbidity and mortality associated with PF, there is no available treatment that efficiently and effectively treats the disease by reversing their underlying pathologies. In recent years, many therapeutic regimens, for instance, rho kinase inhibitors, Smad signaling pathway inhibitors, p38, BCL-xL/ BCL-2 and JNK pathway inhibitors, have been found to be potent and effective in treating PF, in preclinical stages. However, due to non-selectivity and non-specificity, the therapeutic molecules also result in toxicity mediated severe side effects. Hence, this review demonstrates recent advances on PF pathology, mechanism and targets related to PF, development of various drug delivery systems based on small molecules, RNAs, oligonucleotides, peptides, antibodies, exosomes, and stem cells for the treatment of PF and the progress of various therapeutic treatments in clinical trials to advance PF treatment.

Aging aggravates liver fibrosis through downregulated hepatocyte SIRT1-induced liver sinusoidal endothelial cell dysfunction

BACKGROUND

Aging increases the susceptibility to chronic liver diseases and hastens liver fibrosis deterioration, but the underlying mechanisms remain partially understood. The aim of this study was to investigate the effect of aging and chronic liver diseases on hepatocyte Sirtuin 1 (SIRT1) and LSECs and their contribution to liver fibrosis pathogeneses.

METHODS

Young (8-12 wk) and aged (18-20 mo) mice were subjected to carbon tetrachloride-induced liver fibrosis. Primary HSCs and LSECs were isolated and cocultured for in vitro experiments. Liver tissues and blood samples from healthy controls and patients with liver fibrosis were analyzed.

RESULTS

Downregulated hepatocytes SIRT1 in aged mice increased high mobility group box 1 acetylation, cytoplasmic translocation, and extracellular secretion, causing LSECs dysfunction by means of the toll-like receptor 4/AK strain transforming (AKT)/endothelial nitric oxide synthase pathway, ultimately activating HSCs and increasing susceptibility to liver injury and fibrosis. Adeno-associated virus-mediated overexpression of SIRT1 in hepatocytes suppressed the abovementioned alterations and attenuated carbon tetrachloride-induced liver injury and fibrosis in liver fibrosis mice, and there were no significant differences in liver injury and fibrosis indicators between young and aged mice after SIRT1 overexpression treatment. In vitro experiments demonstrated that SIRT1 overexpression and endothelial nitric oxide synthase agonist YC-1 improved LSECs function and inhibited HSCs activation, mediated by nitric oxide. Similarly, downregulated hepatocytes SIRT1 and LSECs dysfunction were observed in the livers of aged individuals compared to young individuals and were more pronounced in aged patients with liver fibrosis.

CONCLUSIONS

Aging aggravates liver fibrosis through downregulated hepatocytes SIRT1-induced LSECs dysfunction, providing a prospective curative approach for preventing and treating liver fibrosis.

Overexpression of HMGB1 in hepatocytes accelerates PTEN inactivation-induced liver cancer

BACKGROUND

Liver cancer is increasing due to the rise in metabolic dysfunction-associated steatohepatitis (MASH). High-mobility group box-1 (HMGB1) is involved in the pathogenesis of chronic liver disease, but its role in MASH-associated liver cancer is unknown. We hypothesized that an increase in hepatocyte-derived HMGB1 in a mouse model of inactivation of PTEN that causes MASH could promote MASH-induced tumorigenesis.

METHODS

We analyzed publicly available transcriptomics datasets, and to explore the effect of overexpressing HMGB1 in cancer progression, we injected 1.5-month-old Pten∆Hep mice with adeno-associated virus serotype-8 (AAV8) vectors to overexpress HMGB1-EGFP or EGFP, and sacrificed them at 3, 9 and 11 months of age.

RESULTS

We found that HMGB1 mRNA increases in human MASH and MASH-induced hepatocellular carcinoma (MASH-HCC) compared to healthy livers. Male and female Pten∆Hep mice overexpressing HMGB1 showed accelerated liver tumor development at 9 and 11 months, respectively, with increased tumor size and volume, compared to control Pten∆Hep mice. Moreover, Pten∆Hep mice overexpressing HMGB1, had increased incidence of mixed HCC-intrahepatic cholangiocarcinoma (iCCA). All iCCAs were positive for nuclear YAP and SOX9. Male Pten∆Hep mice overexpressing HMGB1 showed increased cell proliferation and F4/80+ cells at 3 and 9 months.

CONCLUSION

Overexpression of HMGB1 in hepatocytes accelerates liver tumorigenesis in Pten∆Hep mice, enhancing cell proliferation and F4/80+ cells to drive MASH-induced liver cancer.

Sirtuin 1 alleviates alcoholic liver disease by inhibiting HMGB1 acetylation and translocation

Background

Alcoholic liver disease (ALD) encompasses a spectrum of liver disorders resulting from prolonged alcohol consumption and is influenced by factors such as oxidative stress, inflammation, and apoptosis. High Mobility Group Box 1 (HMGB1) plays a pivotal role in ALD due to its involvement in inflammation and immune responses. Another key factor, Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, is known for its roles in cellular stress responses and metabolic regulation. Despite individual studies on HMGB1 and SIRT1 in ALD, their specific molecular interactions and combined effects on disease advancement remain incompletely understood.

Methods

Alcohol-induced liver injury (ALI) models were established using HepG2 cells and male C57BL/6 mice. HMGB1 and SIRT1 expressions were assessed at the mRNA and protein levels usingreverse transcription-quantitative polymerase chain reaction, western blot, and immunofluorescence staining. The physical interaction between HMGB1 and SIRT1 was investigated using co-immunoprecipitation and immunofluorescence co-expression analyses. Cellular viability was evaluated using the CCK-8 assay.

Results

In patients with clinical ALI, HMGB1 mRNA levels were elevated, while SIRT1 expression was reduced, indicating a negative correlation between the two. ALI models were successfully established in cells and mice, as evidenced by increased markers of cellular and liver damage. HMGB1 acetylation and translocation were observed in both ALI cells and mouse models. Treatment with the SIRT1 agonist, SRT1720, reversed the upregulation of HMGB1 acetylation, nuclear translocation, and release in the ethyl alcohol (EtOH) group. Furthermore, SIRT1 significantly attenuated ALI. Importantly, in vivo binding was confirmed between SIRT1 and HMGB1.

Conclusions

SIRT1 alleviates HMGB1 acetylation and translocation, thereby ameliorating ALI.

Hepatic Macrophages as Targets for the MSC-Based Cell Therapy in Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) is a serious public health issue associated with the obesity pandemic. Obesity is the main risk factor for the non-alcoholic fatty liver disease (NAFLD), which progresses to NASH and then to end-stage liver disease. Currently, there are no specific pharmacotherapies of NAFLD/NASH approved by the FDA or other national regulatory bodies and the treatment includes lifestyle adjustment and medicines for improving lipid metabolism, enhancing sensitivity to insulin, balancing oxidation, and counteracting fibrosis. Accordingly, further basic research and development of new therapeutic approaches are greatly needed. Mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles prevent induced hepatocyte death in vitro and attenuate NASH symptoms in animal models of the disease. They interact with hepatocytes directly, but also target other liver cells, including Kupffer cells and macrophages recruited from the blood flow. This review provides an update on the pathogenesis of NAFLD/NASH and the key role of macrophages in the development of the disease. We examine in detail the mechanisms of the cross-talk between the MSCs and the macrophages, which are likely to be among the key targets of MSCs and their derivatives in the course of NAFLD/NASH cell therapy.

RAGE deficiency ameliorates autoimmune hepatitis involving inhibition of IL-6 production via suppressing protein Arid5a in mice

Activation of T cells and pro-inflammatory cytokines are essential for human autoimmune hepatitis. RAGE is one of the receptors for the inflammatory alarm molecule high mobility group box 1 (HMGB1), and it is involved in autoimmune hepatitis. However, the molecular mechanism of RAGE in the context of autoimmune hepatitis remains elusive. This study aimed to identify the function and mechanism of RAGE in autoimmune hepatitis. The role and underlying mechanisms of RAGE signaling-driven immune inflammatory response in ConA-induced experimental hepatitis were examined using the RAGE-deficient mice. We found that the RAGE deficiency protected the mouse from liver inflammatory injury caused by the ConA challenge. mRNA expression of VCAM-1, IL-6, and TNF-α within the livers is markedly decreased in RAGE-deficient mice compared to wild-type mice. In parallel, RAGE deficiency leads to reduced levels of the serum pro-inflammatory cytokines IL-6 and TNF-α as compared with wild-type control mice. RAGE-deficient mice exhibit increased hepatic NK cells and decreased CD4+ T cells compared with wild-type control mice. Notably, in vivo blockade of IL-6 in wild-type mice significantly protected mice from ConA-induced hepatic injury. Furthermore, RAGE deficiency impaired IL-6 production and was associated with decreased expression of Arid5a in liver tissues, a half-life IL-6 mRNA regulator. RAGE signaling is important in regulating the development of autoimmune hepatitis. Immune regulation of RAGE may represent a novel therapeutic strategy to prevent immune-mediated liver injury.

MANF brakes TLR4 signaling by competitively binding S100A8 with S100A9 to regulate macrophage phenotypes in hepatic fibrosis

The mesencephalic astrocyte-derived neurotrophic factor (MANF) has been recently identified as a neurotrophic factor, but its role in hepatic fibrosis is unknown. Here, we found that MANF was upregulated in the fibrotic liver tissues of the patients with chronic liver diseases and of mice treated with CCl4. MANF deficiency in either hepatocytes or hepatic mono-macrophages, particularly in hepatic mono-macrophages, clearly exacerbated hepatic fibrosis. Myeloid-specific MANF knockout increased the population of hepatic Ly6Chigh macrophages and promoted HSCs activation. Furthermore, MANF-sufficient macrophages (from WT mice) transfusion ameliorated CCl4-induced hepatic fibrosis in myeloid cells-specific MANF knockout (MKO) mice. Mechanistically, MANF interacted with S100A8 to competitively block S100A8/A9 heterodimer formation and inhibited S100A8/A9-mediated TLR4-NF-κB signal activation. Pharmacologically, systemic administration of recombinant human MANF significantly alleviated CCl4-induced hepatic fibrosis in both WT and hepatocytes-specific MANF knockout (HKO) mice. This study reveals a mechanism by which MANF targets S100A8/A9-TLR4 as a "brake" on the upstream of NF-κB pathway, which exerts an impact on macrophage differentiation and shed light on hepatic fibrosis treatment.

RAGE/SNAIL1 signaling drives epithelial-mesenchymal plasticity in metastatic triple-negative breast cancer

Epithelial/Mesenchymal (E/M) plasticity plays a fundamental role both in embryogenesis and during tumorigenesis. The receptor for advanced glycation end products (RAGE) is a driver of cell plasticity in fibrotic diseases; however, its role and molecular mechanism in triple-negative breast cancer (TNBC) remains unclear. Here, we demonstrate that RAGE signaling maintains the mesenchymal phenotype of aggressive TNBC cells by enforcing the expression of SNAIL1. Besides, we uncover a crosstalk mechanism between the TGF-β and RAGE pathways that is required for the acquisition of mesenchymal traits in TNBC cells. Consistently, RAGE inhibition elicits epithelial features that block migration and invasion capacities. Next, since RAGE is a sensor of the tumor microenvironment, we modeled acute acidosis in TNBC cells and showed it promotes enhanced production of RAGE ligands and the activation of RAGE-dependent invasive properties. Furthermore, acute acidosis increases SNAIL1 levels and tumor cell invasion in a RAGE-dependent manner. Finally, we demonstrate that in vivo inhibition of RAGE reduces metastasis incidence and expands survival, consistent with molecular effects that support the relevance of RAGE signaling in E/M plasticity. These results uncover new molecular insights on the regulation of E/M phenotypes in cancer metastasis and provide rationale for pharmacological intervention of this signaling axis.

Diacerein ameliorates cholestasis-induced liver fibrosis in rat via modulating HMGB1/RAGE/NF-κB/JNK pathway and endoplasmic reticulum stress

Diacerein is an interleukin (IL)-1β inhibitor approved for osteoarthritis. This study aimed to investigate the potential anti-fibrotic effect of diacerein against bile duct ligation (BDL)-induced liver fibrosis. Forty male Wistar rats were divided into: sham-operated group, BDL group, and BDL groups treated with diacerein at 10, 30, and 50 mg/kg/day starting two days before surgery and continued for 4 weeks. Diacerein decreased the hepatic injury markers and alleviated oxidative stress triggered by BDL by reducing hepatic malondialdehyde (MDA) and increasing hepatic superoxide dismutase (SOD) levels. Diacerein mitigated BDL-induced inflammation via lowering hepatic levels and mRNA expression of high mobility group box 1 (HMGB1), nuclear factor-κB (NF-κB), and IL-1β. The hepatic gene expression of Advanced Glycation End products Receptor (RAGE) gene and immunohistochemical expression of some ER stress markers, e.g., glucose-regulated protein 78 (GRP78), inositol-requiring enzyme 1 (IRE1α), protein kinase RNA-like endoplasmic reticulum kinase (PERK), CCAAT/enhancer-binding protein homologous protein (CHOP), and phosphorylated c-Jun N-terminal kinase protein contents were lowered by diacerein. Furthermore, diacerein suppressed the hepatic levels of fibrogenic mediators, e.g., Transforming growth factor β1 (TGF-β1), α- smooth muscle actin (α-SMA), collagen 1, and hydroxyproline, as well as the apoptotic caspase 3 and BAX immunostaining in BDL rats. The histopathological abnormalities induced by BDL significantly improved. Our study demonstrated that diacerein exhibited an antifibrotic effect by inhibiting HMGB1/RAGE/NF-κB/JNK pathway, and ER stress. Better protection was observed with increasing the dose.

HMGB1-mediated elevation of KLF7 facilitates hepatocellular carcinoma progression and metastasis through upregulating TLR4 and PTK2

Background: Metastasis is a major cause of HCC-related deaths with no effective pharmacotherapies. Chronic inflammation promotes HCC dissemination, however, its underlying mechanisms are not fully understood. Here, we investigated the role of Krüppel-like factor 7 (KLF7) in inflammation-provoked HCC metastasis and proposed therapeutic strategies for KLF7-positive patients. Methods: The expression of KLF7 in human HCC specimens were examined by immunohistochemistry and quantitative real-time PCR. The luciferase reporter assays and chromatin immunoprecipitation assays were conducted to explore the transcriptional regulation related to KLF7. Orthotopic xenograft models and DEN/CCl4-induced HCC models were established to evaluate HCC progression and metastasis. Results: KLF7 overexpression promotes HCC metastasis through transactivating toll-like receptor 4 (TLR4) and protein tyrosine kinase 2 (PTK2) expression. High mobility group box 1 (HMGB1) upregulates KLF7 expression through the TLR4/advanced glycosylation end-product specific receptor (RAGE)-PI3K-AKT-NF-κB pathway, forming an HMGB1-KLF7-TLR4 positive feedback loop. The HMGB1-KLF7-TLR4/PTK2 axis is gradually activated during the progression of inflammation-HCC transition. Genetic depletion of KLF7 impedes HMGB1-mediated HCC progression and metastasis. The combined application of TLR4 inhibitor TAK-242 and PTK2 inhibitor defactinib alleviates HCC progression and metastasis induced by the HMGB1-KLF7 axis. In human HCCs, KLF7 expression is positively correlated with cytoplasmic HMGB1, p-p65, TLR4, and PTK2 levels, and patients positively co-expressing HMGB1/KLF7, p-p65/KLF7, KLF7/TLR4 or KLF7/PTK2 exhibit the worst prognosis. Conclusions: HMGB1-induced KLF7 overexpression facilitates HCC progression and metastasis by upregulating TLR4 and PTK2. Genetic ablation of KLF7 via AAV gene therapy and combined blockade of TLR4 and PTK2 represents promising therapy strategies for KLF7-positive HCC patients.

Targeting Endothelial Necroptosis Disrupts Profibrotic Endothelial-Hepatic Stellate Cells Crosstalk to Alleviate Liver Fibrosis in Nonalcoholic Steatohepatitis

Chronic liver diseases affect over a billion people worldwide and often lead to fibrosis. Nonalcoholic steatohepatitis (NASH), a disease paralleling a worldwide surge in metabolic syndromes, is characterized by liver fibrosis, and its pathogenesis remains largely unknown, with no effective treatment available. Necroptosis has been implicated in liver fibrosis pathogenesis. However, there is a lack of research on necroptosis specific to certain cell types, particularly the vascular system, in the context of liver fibrosis and NASH. Here, we employed a mouse model of NASH in combination with inducible gene knockout mice to investigate the role of endothelial necroptosis in NASH progression. We found that endothelial cell (EC)-specific knockout of mixed lineage kinase domain-like protein (MLKL), a critical executioner involved in the disruption of cell membranes during necroptosis, alleviated liver fibrosis in the mouse NASH model. Mechanistically, EC-specific deletion of Mlkl mitigated the activation of TGFβ/Smad 2/3 pathway, disrupting the pro-fibrotic crosstalk between endothelial cells and hepatic stellate cells (HSCs). Our findings highlight endothelial MLKL as a promising molecular target for developing therapeutic interventions for NASH.

Advanced Biomarkers of Hepatotoxicity in Psychiatry: A Narrative Review and Recommendations for New Psychoactive Substances

One of the factors that increase the effectiveness of the pharmacotherapy used in patients abusing various types of new psychoactive substances (NPSs) is the proper functioning of the liver. However, the articles published to date on NPS hepatotoxicity only address non-specific hepatic parameters. The aim of this manuscript was to review three advanced markers of hepatotoxicity in psychiatry, namely, osteopontin (OPN), high-mobility group box 1 protein (HMGB1) and glutathione dehydrogenase (GDH, GLDH), and, on this basis, to identify recommendations that should be included in future studies in patients abusing NPSs. This will make it possible to determine whether NPSs do indeed have a hepatotoxic effect or whether other factors, such as additional substances taken or hepatitis C virus (HCV) infection, are responsible. NPS abusers are at particular risk of HCV infection, and for this reason, it is all the more important to determine what factors actually show a hepatotoxic effect in them.

Age-dependent loss of hepatic SIRT1 enhances NLRP3 inflammasome signaling and impairs capacity for liver fibrosis resolution

Our studies indicate that the longevity factor SIRT1 is implicated in metabolic disease; however, whether and how hepatocyte-specific SIRT1 signaling is involved in liver fibrosis remains undefined. We characterized a functional link of age-mediated defects in SIRT1 to the NLRP3 inflammasome during age-related liver fibrosis. In multiple experimental murine models of liver fibrosis, we compared the development of liver fibrosis in young and old mice, as well as in liver-specific SIRT1 knockout (SIRT1 LKO) mice and wild-type (WT) mice. Liver injury, fibrosis, and inflammation were assessed histologically and quantified by real-time PCR analysis. In a model of hepatotoxin-induced liver fibrosis, old mice displayed more severe and persistent liver fibrosis than young mice during liver injury and after injury cessation, as characterized by inhibition of SIRT1, induction of NLRP3, infiltration of macrophages and neutrophils, activation of hepatic stellate cells (HSCs), and excessive deposition and remodeling of the extracellular matrix. Mechanistically, deletion of SIRT1 in hepatocytes resulted in NLRP3 and IL-1β induction, pro-inflammatory response, and severe liver fibrosis in young mice, mimicking the ability of aging to impair the resolution of established fibrosis. In an aging mouse model, chronic-plus-binge alcohol feeding-induced liver fibrosis was attenuated by treatment with MCC950, a selective NLRP3 inhibitor. NLRP3 inhibition ameliorated alcoholic liver fibrosis in old mice by repressing inflammation and reducing hepatocyte-derived danger signaling-ASK1 and HMGB1. In conclusion, age-dependent SIRT1 defects lead to NLRP3 activation and inflammation, which in turn impairs the capacity to resolve fibrosis during aging.

RAGE pathways play an important role in regulation of organ fibrosis

Organ fibrosis is a pathological process of fibroblast activation and excessive deposition of extracellular matrix after persistent tissue injury and therefore is a common endpoint of many organ pathologies. Multiple cellular types and soluble mediators, including chemokines, cytokines and non-peptidic factors, are implicated in fibrogenesis and the remodeling of tissue architecture. The molecular basis of the fibrotic process is complex and consists of closely intertwined signaling networks. Research has strived for a better understanding of these pathological mechanisms to potentially reveal novel therapeutic targets for fibrotic diseases. In light of new knowledge, the receptor for advanced glycation end products (RAGE) emerged as an important candidate for the regulation of a wide variety of cellular functions related to fibrosis, including inflammation, cell proliferation, apoptosis, and angiogenesis. RAGE is a pattern recognition receptor that binds a broad range of ligands such as advanced glycation end products, high mobility group box-1, S-100 calcium-binding protein and amyloid beta protein. Although the link between RAGE and fibrosis has been established, the exact mechanisms need be investigated in further studies. The aim of this review is to collect all available information about the intricate function of RAGE and its signaling cascades in the pathogenesis of fibrotic diseases within different organs. In addition, to the major ligands and signaling pathways, we discuss potential strategies for targeting RAGE in fibrosis. We emphasize the functional links between RAGE, inflammation and fibrosis that may guide further studies and the development of improved therapeutic drugs.

Macrophage pyroptosis promotes synovial fibrosis through the HMGB1/TGF- β1 axis: an in vivo and in vitro study

Macrophages and fibroblasts are the main effector cells in synovial tissue in the knee joint. Our previous studies showed that there was synovial macrophage pyroptosis in knee osteoarthritis (KOA) and that inhibiting this pyroptosis could alleviate synovial fibrosis. In the present study, we aimed to elucidate the mechanism by which macrophage pyroptosis affects synovial fibrosis. We established an LPS/ATP-induced model in macrophages that mimicked the inflammatory environment of KOA and induced macrophage pyroptosis. The TGF-β1, SMAD3, and P-SMAD3, and the synovial fibrosis markers (Collagen I, TIMP1, Vimentin, and TGF-β1) were significantly decreased after fibroblasts were cultured with RAGE inhibitors and SMAD3 inhibitors. Moreover, ELISA and immunofluorescence analysis showed that macrophage pyroptosis induced the release of IL-1β, IL-18, and HMGB1 and caused the translocation of HMGB1 from the fibroblast nucleus to the cell membrane, where it could bind with RAGE. Subsequently, in the synovial tissue of KOA model rats, we observed that inhibiting HMGB1, RAGE, and SMAD3 could alleviate the expression of synovial fibrosis markers (Collagen I, TIMP1, Vimentin, and TGF-β1) at both the mRNA and protein levels. Besides, HE and Sirius Red staining were used to observe the transverse diameter of the right knee. In conclusion, macrophage pyroptosis induced IL-1β, IL-18, and HMGB1, which could be caused HMGB1 to translocate from the fibroblast nucleus and bind with RAGE, activating the TGF-β1/SMAD3 signaling pathway and affecting synovial fibrosis.

S100A6 Activates Kupffer Cells via the p-P38 and p-JNK Pathways to Induce Inflammation, Mononuclear/macrophage Infiltration Sterile Liver Injury in Mice

Noninfectious liver injury, including the effects of chemical material, drugs and diet, is a major cause of liver diseases worldwide. In chemical and drugs-induced liver injury, innate inflammatory responses are mediated by extracellular danger signals. The S100 protein can act as danger signals, which can promote the migration and chemotaxis of immune cells, promote the release of various inflammatory cytokines, and regulate the body's inflammatory and immune responses. However, the role of S100A6 in inflammatory response in chemical and drugs-induced sterile liver injury remains unclear. We constructed the model of sterile liver injury induced by carbon tetrachloride (CCl₄)/Paracetamol (APAP) and performed RNA sequencing (RNA-seq) on the liver tissues after injury (days 2 and 5). We analyzed inflammatory protein secretion in the liver tissue supernatant by enzyme-linked immunosorbent assay (ELISA), determined the inflammation response by bioinformatic analysis during sterile liver injury, and assessed mononuclear/macrophage infiltration by immunohistochemistry and flow cytometry. Immunohistochemistry was used to analyze the location of S100A6. We conducted inflammatory factor expression analysis and molecular mechanistic studies in Kupffer cells (KCs) induced by S100A6 using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), ELISA, and western blot in vitro experiments. We performed chemokine CCL2 expression analysis and molecular mechanism studies using the same method. We used a Transwell assay to show the infiltration of mononuclear/macrophage. We here observed that aggravated inflammatory response was shown in CCl₄ and APAP-administrated mice, as evidenced by enhanced production of inflammatory cytokines (TNF-α, IL-1β), and elevated mononuclear/macrophage infiltration and activation of immunity. The expression of S100A6 was significantly increased on day 2 after sterile liver injury, which is primarily produced by injured liver cells. Mechanistic studies established that S100A6 activates Kupffer cells (KCs) via the p-P38, p-JNK and P65 pathways to induce inflammation in vitro. Furthermore, TNF-α can stimulate liver cells via the p-P38 and p-JNK pathways to produce CCL2 and promote the infiltration of mononuclear/macrophage. In summary, we showed that S100A6 plays an important role in regulating inflammation, thus influencing sterile liver injury. Our findings provide novel evidence that S100A6 can as a danger signal that contributes to pro-inflammatory activation through p-P38 and p-JNK pathways in CCl₄ and APAP-induced sterile liver injury in mice. In addition, the inflammatory factor TNF-α induces a large amount of CCL2 production in normal liver cells surrounding the injured area through a paracrine action, which is chemotactic for blood mononuclear/macrophage infiltration.

Three-Dimensional Cell Co-Culture Liver Models and Their Applications in Pharmaceutical Research

As the primary site for the biotransformation of drugs, the liver is the most focused on organ type in pharmaceutical research. However, despite being widely used in pharmaceutical research, animal models have inherent species differences, while two-dimensional (2D) liver cell monocultures or co-cultures and three-dimensional (3D) liver cell monoculture in vitro liver models do not sufficiently represent the complexity of the human liver’s structure and function, making the evaluation results from these tools less reliable. Therefore, there is a pressing need to develop more representative in vitro liver models for pharmaceutical research. Fortunately, an exciting new development in recent years has been the emergence of 3D liver cell co-culture models. These models hold great promise as in vitro pharmaceutical research tools, because they can reproduce liver structure and function more practically. This review begins by explaining the structure and main cell composition of the liver, before introducing the potential advantages of 3D cell co-culture liver models for pharmaceutical research. We also discuss the main sources of hepatocytes and the 3D cell co-culture methods used in constructing these models. In addition, we explore the applications of 3D cell co-culture liver models with different functional states and suggest prospects for their further development.

Pro-fibrogenic role of alarmin high mobility group box 1 in HIV-hepatitis B virus coinfection

OBJECTIVE

Liver disease is accelerated in people with HIV (PWH) with hepatitis B virus (HBV) coinfection. We hypothesized that liver fibrosis in HIV-HBV is triggered by increased hepatocyte apoptosis, microbial translocation and/or HIV/HBV viral products.

DESIGN

Sera from PWH with HBV coinfection versus from those with HBV only or putative mediators were used to examine the pathogenesis of liver disease in HIV-HBV.

METHODS

We applied sera from PWH and HBV coinfection versus HBV alone, or putative mediators (including HMGB1), to primary human hepatic stellate cells (hHSC) and examined pro-fibrogenic changes at the single cell level using flow cytometry. High mobility group box 1 (HMGB1) levels in the applied sera were assessed according to donor fibrosis stage.

RESULTS

Quantitative flow cytometric assessment of pro-fibrogenic and inflammatory changes at the single cell level revealed an enhanced capacity for sera from PWH with HBV coinfection to activate hHSC. This effect was recapitulated by lipopolysaccharide, HIV-gp120, hepatocyte conditioned-media and the alarmin HMGB1. Induction of hepatocyte cell death increased their pro-fibrogenic potential, an effect blocked by HMGB1 antagonist glycyrrhizic acid. Consistent with a role for this alarmin, HMGB1 levels were elevated in sera from PWH and hepatitis B coinfection compared to HBV alone and higher in those with HIV-HBV with liver fibrosis compared to those without.

CONCLUSIONS

Sera from PWH and HBV coinfection have an enhanced capacity to activate primary hHSC. We identified an increase in circulating HMGB1 which, in addition to HIV-gp120 and translocated microbial products, drove pro-fibrogenic changes in hHSC, as mechanisms contributing to accelerated liver disease in HIV-HBV.

Effects and mechanisms of Xiaochaihu Tang against liver fibrosis: An integration of network pharmacology, molecular docking and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Liver fibrosis is a potentially harmful chronic liver disease caused by various etiologies. There is currently no specific drug for liver fibrosis. Xiaochaihu Tang (XCHT) is a traditional formula combined of seven herbs, which was first recorded in the Treatise on Febrile Diseases in Han Dynasty of ancient China. It is widely used in clinic to hepatic protection, analgesic, antipyretic and anti-inflammatory treatment. And it has been recommended for treating chronic hepatitis and chronic cholecystitis in the latest guidelines for the diagnosis and treatment of liver fibrosis with integrated traditional and western medicine. However, the underlying regulatory mechanisms remain elusive.

AIM OF THE STUDY

This study aims to explore the therapeutic effects of XCHT on liver fibrosis and its underlying molecular mechanisms from the perspective of network pharmacology and experimental research.

MATERIALS AND METHODS

Carbon tetrachloride (CCl₄) induced and bile duct ligation (BDL) induced liver fibrosis models in mice were established to evaluate the anti-fibrosis effects of XCHT in vivo. Potential anti-fibrosis targets of XCHT were screened via network establishment. The underlying mechanisms were uncovered through GO and pathway enrichment analysis. Then, the core targets were identified from protein-protein interaction network by means of the Cytohubba plug-in of Cytoscape. Furthermore, two effective monomer components of XCHT were recognized by molecular docking. Moreover, the predicted components and pathways were verified by in vitro experiments.

RESULTS

When treated with XCHT, liver fibrosis was alleviated in both mice models, showing as the improvement of liver function, the protection of hepatocytes, the inhibition of HSC activation and the reduction of hepatic collagen accumulation. 540 monomer components, 300 therapeutic targets, 109 signaling pathways, 246 GO biological processes, 77 GO cellular components, 107 GO molecular functions items and core targets were identified by network analysis. Then, 6-gingerol and baicalein were identified as the core components of anti-fibrosis effects of XCHT via leptin or Nrf2 signaling pathway. Furthermore, the experiment in vitro also validated the results.

CONCLUSIONS

Our study suggests XCHT could alleviate liver fibrosis through multi-targets and multi-pathways; 6-gingerol and baicalein are its core components which may play an important role via leptin or Nrf2 signaling pathway.