Hepatic mitochondrial DNA/Toll-like receptor 9/MicroRNA-223 forms a negative feedback loop to limit neutrophil overactivation and acetaminophen hepatotoxicity in mice

A review on the lncRNA-miRNA-mRNA regulatory networks involved in inflammatory processes in Alzheimer's disease

Alzheimer's disease is a progressive neurodegenerative condition that is the most frequent reason for dementia. Due to the increasing trend of aging in societies, it will place a large social and financial burden on society. Although beta amyloid plaques and the formation of neurofibrillary tangles are mentioned as the main events in this disorder, the exact molecular pathology and inflammatory regulatory networks involved in neuroinflammatory events, as a fundamental pathogenic mechanism remain unknown. Understanding these molecular network pathways in addition to helping to understand the pathogenesis of Alzheimer's disease, can also help in the early diagnosis as well as the control of inflammatory processes that are involved in its progression. So, in this study, we intend to have an overview on the regulatory lncRNAs of Alzheimer's disease and their related miRNA and mRNAs, as well as the relationship of these regulatory pathways with inflammatory processes, so that we can provide a perspective for future studies in the field of diagnosis and possibly treatment of this disorder.

The different innate immune response to infections in males and females emerges before birth

AIM

Sex-specific immune responses to intra-amniotic infections remain poorly understood despite their key role in preterm birth.

METHODS

We infected male and female amniotic fluid cells (AFCs) with M. hominis to explore the potential impact of sex-specific innate immune responses, evaluating the gene and protein expression levels of IL-1β, IL-6, IL-8, TNF-α, TLR2 and TLR4, the production of nitrites, and the levels of selected miRNAs.

KEY FINDINGS

The gene expression of IL-1β, IL-6, IL-8, TNF-α, and TLR2 were elevated in infected females AFCs, while only IL-6, IL-8 and TLR4 expression were up-regulated in infected males. Protein levels of IL-6, TNF-α and TLR2 were up-regulated exclusively in infected females. Furthermore, infected female AFCs produced higher levels of nitrites. MiRNA expression revealed an up-regulation of miR-29a-3p in infected females, and miR-223-3p in infected males, with miR-29b-3p showing up-regulation in both sexes upon infection.

SIGNIFICANCE

The response to intrauterine infections differs between males and females. Female foetuses may possess a greater capacity to manage the infection and inflammation, underscoring the importance of personalized prenatal care.

Alcoholic cirrhosis-associated immune dysfunction: What does it imply for us?

Alcoholic cirrhosis is a leading cause of chronic advanced liver disease. With the gradual eradication of viral hepatitis and the rising levels of alcohol consumption, the incidence of alcoholic cirrhosis is expected to increase steadily. Alcohol is primarily metabolized in the gastrointestinal tract, producing toxic metabolites that enter the portal vein circulation and are subsequently transported to the liver. Excessive alcohol intake activates the microsomal ethanol oxidation system and disrupts the intestinal microbiota-driven microenvironment dictated by intestinal microbiota, and increase intestinal permeability, all of which trigger severe systemic inflammatory responses and impaired immune function. This phenomenon, known as cirrhosis-associated immune dysfunction (CAID), is closely linked to the severity of cirrhosis and can significantly influence disease progression, potentially leading to multi-organ failure. This narrative review sheds light on the relationship between alcoholic cirrhosis and CAID, focusing on tailored interventions to modify immune response and modulate gut microbiota composition in hopes of mitigating the development and deterioration of alcoholic cirrhosis.

Molecular dynamics of inflammation resolution: therapeutic implications

Inflammation is a critical part of innate immune response that is essential for exclusion of harmful stimuli and restoration of tissue homeostasis. Nonetheless, failure to resolve inflammation results in chronic inflammatory conditions, including autoimmune diseases. Conventionally, resolution of inflammation was deemed a passive process; however, evidence indicates that it entails active, highly regulated molecular and cellular events involving efferocytosis-driven macrophage reprogramming, post-transcriptional regulatory mechanisms and the production of specialized pro-resolving mediators (SPMs). These processes collectively restore tissue homeostasis and prevent chronic inflammation. Emerging therapeutic approaches targeting these pathways demonstrate promising results in preclinical studies and clinical trials, enhancing resolution and improving overall disease outcome. This resulted in a paradigm shift from conventional anti-inflammatory strategies to resolution-focused treatment. Yet, challenges remain due to the complexity of resolution mechanisms and tissue-specific differences. This review summarizes current advances in inflammation resolution, emphasizing emerging concepts of resolution pharmacology. By employing endogenous mechanisms facilitating resolution, novel therapeutic applications can effectively manage several chronic inflammatory disorders.

miR-301a-5p regulated IKKβ/NF-κB axis and macrophage polarization to accelerate skin wound healing

Wound healing is a highly coordinated biological process encompassing four distinct yet interconnected stages. Notably, microRNA (miRNA) dysregulation is related to non-healing wounds, and miRNAs are considered promising therapeutic targets for wound healing. However, its function and underlying mechanism in wound healing remain incompletely understood. Here, we detected and characterized the miRNA expression patterns during wound healing. Interestingly, miR-301a-5p was significantly downregulated in the initial inflammatory stage and finally peaked in early proliferative phases, suggesting its potential role in modulating phase transition from inflammatory to proliferative phase. Moreover, miR-301a-5p not only promoted the proliferation and migration of macrophages, but also suppressed the excessive inflammatory response, as evidenced by both facilitating the expression of IL-10 and TGF-β and suppressing the pro-inflammatory factors expression. Mechanistically, miR-301a-5p directly targeted inhibitor of κB kinaseβ (IKKβ) and regulated its expression to modulate nuclear factor κB (NF-κB) pathway and macrophage polarization (M1 to M2). Importantly, miR-301a-5p overexpression significantly promoted the regeneration of full-thickness skin wound in mice by regulating NF-κB and macrophage polarization, thereby facilitating epidermal regeneration and collagen deposition. Together, our study found that miR-301a-5p as a novel regulator in the wound healing process transition, and provided potent pro-healing agents for wound healing.

Multiple cell-type interactions drive invariant NKT cell hepatitis

BACKGROUND

α-Galactosylceramide (α-Galcer), a specific ligand for invariant natural killer T (NKT) cell activation, has been actively investigated in clinical trials such as antitumor therapy; however, treatment with α-Galcer is well known to induce acute hepatitis due to enriched NKT cells in the liver. The molecular mechanisms underlying NKT-mediated hepatitis still remain obscure. The object of this study was to investigate whether and how myeloid cells affect NKT-mediated hepatitis.

METHODS

α-Galcer-induced NKT hepatitis was used in this study. microRNA-223 (miR-223) and neutrophil cytosolic factor 1 (Ncf1)-deficent mice were generated and subjected to α-Galcer-induced NKT hepatitis.

RESULTS

In this study, we demonstrated that α-Galcer-induced NKT cell activation resulted in neutrophil and monocyte-derived macrophage accumulation in the liver. Importantly, serum levels of several hepatic myeloid cell infiltration-related cytokines and chemokines were significantly elevated after α-Galcer administration. Among these myeloid cells, blockade of neutrophil or macrophage migration through using different inhibitors of (C-X-C Motif) receptor 2, (C-C motif) receptor 2, and (C-C motif) receptor 5 signaling ameliorated α-Galcer-induced liver injury, mainly due to the decrease of reactive oxygen species production and inflammation. Depletion of neutrophils reduced α-Galcer-induced liver injury and hepatitis. Interestingly, genetic deletion of neutrophil-specific miR-223 markedly enhanced while Ncf1 deficiency significantly ameliorated liver inflammation and oxidative damage caused by α-Galcer.

CONCLUSIONS

Neutrophil and macrophage infiltration through multiple inflammatory mediators is required for NKT cell activation-induced hepatitis, which sheds light on the myeloid cell infiltration-related molecular mechanisms of NKT cell-mediated liver injury. Our study may provide a novel therapeutical strategy for the treatment of NKT cell hepatitis.

Isorhapontigenin alleviates acetaminophen-induced liver injury by promoting fatty acid oxidation

Acetaminophen (APAP) is a widely used analgesic and antipyretic medicine. It is frequently employed to alleviate pain and mitigate fever-related symptoms, but it can cause liver injury or even liver failure when overdosed. Isorhapontigenin, a compound derived from Chinese herbs and grapes, has been demonstrated to exhibit antioxidant and anti-inflammatory effects. This study focused on evaluating the effect of isorhapontigenin in alleviating APAP-induced liver injury. In the study, a single intraperitoneal administration of APAP was employed to induce liver injury, and isorhapontigenin was given orally 3 days before or 1 h after APAP administration. The results revealed that isorhapontigenin significantly mitigated liver injury by effectively inhibiting APAP-induced apoptosis, oxidative stress, and inflammation. Furthermore, transcriptomic RNA sequencing of liver tissues indicated that isorhapontigenin probably protected against APAP-induced liver injury by promoting fatty acid oxidation. Pharmacological experiments also demonstrated that isorhapontigenin treatment led to a significant reduction in triglyceride accumulation, increased ATP levels and direct fatty acid oxidation activity, as well as enhanced expression of proteins associated with fatty acid oxidation, including PPAR-α, PGC-1α, and CPT-1A. Moreover, the protective effects of isorhapontigenin against APAP-induced liver injury were abolished by a CPT-1A inhibitor, etomoxir. Notably, we found that combining isorhapontigenin with NAC (N-acetyl-L-cysteine) resulted in a more significant alleviation of APAP-induced liver injury compared to NAC alone. In conclusion, our study indicates that isorhapontigenin is a potential therapeutic strategy that works by regulating fatty acid oxidation to alleviate APAP-induced liver injury.

Unlocking the Potential of miRNAs in Sepsis Diagnosis and Prognosis: From Pathophysiology to Precision Medicine

The clinical syndrome appears as a dysregulated host response to infection that results in life-threatening organ dysfunction known as Sepsis. Sepsis is a serious public health concern where for every five deaths in ICU there is one patient who dies with sepsis worldwide. Sepsis is featured as unbalanced inflammation and immunosuppression which is sustained and profound, increasing patient susceptibility to secondary infections and mortality. microRNAs (miRNAs) play a central role in the control of many biological processes, and the deregulation of their expression has been linked to the development of oncological, cardiovascular, neurodegenerative, and metabolic diseases. In this review, we discuss the role of miRNAs in sepsis pathophysiology. Overall, miRNAs are seen as promising biomarkers, and it has been proposed to develop miRNA-based diagnosis and therapies for sepsis. Yet, the picture is not so straightforward because of miRNAs' versatile and dynamic features. More research is needed to clarify the expression and role of miRNAs in sepsis and promote the use of miRNAs for sepsis management. This study provides an extensive, current, and thorough analysis of the involvement of miRNAs in sepsis. Its purpose is to encourage future research in this area, as tiny miRNAs have the potential to be used for rapid diagnosis, prognosis, and treatment of sepsis.

miR-324-3p Suppresses Hepatic Stellate Cell Activation and Hepatic Fibrosis Via Regulating SMAD4 Signaling Pathway

In hepatic fibrosis (HF), hepatic stellate cells (HSCs) form the extracellular matrix (ECM), and the pathological accumulation of ECM in the liver leads to inflammation. Our previous research found that miR-324-3p was down-regulated in culture-activated human HSCs. However, the precise effect of miR-324-3p on HF has not been elucidated. In this study, the HF mouse models were induced through directly injecting carbon tetrachloride (CCl4) into mice; the HF cell models were constructed using TGF-β1-treated LX-2 cells. Next, real-time-quantitative polymerase chain reaction (RT-qPCR), western blot (WB) and immunohistochemistry (IHC) were applied to assess the expression levels of miR-324-3p, α-smooth muscle actin (α-SMA), Vimentin or SMAD4; hematoxylin and eosin (H&E), Masson' s trichrome and Sirius red staining to evaluate the liver injury; luciferase reporter assay to verify the targeting relationship between miR-324-3p and SMAD4; enzyme-linked immunosorbent assay (ELISA) to determine the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST); and cell counting kit-8 (CCK-8) and flow cytometry to evaluate the effects of miR-324-3p on cell proliferation and cycle/apoptosis, respectively. The experimental results showed a reduction in miR-324-3p level in CCl4-induced HF mice as well as transforming growth factor (TGF)-β1-activated HSCs. Interestingly, the miR-324-3p level was rescued following the HF recovery process. In HF mice induced by CCl4, miR-324-3p overexpression inhibited liver tissue damage, decreased serum ALT and AST levels, and inhibited fibrosis-related biomarkers (α-SMA, Vimentin) expression, thereby inhibiting HF. Similarly, miR-324-3p overexpression up-regulated α-SMA and Vimentin levels in HF cells, while knockdown of miR-324-3p had the opposite effect. Besides, miR-324-3p played an antifibrotic role through inhibiting the proliferation of hepatocytes. Further experiments confirmed that miR-324-3p targeted and down-regulated SMAD4 expression. SMAD4 was highly expressed in HF cells, and silencing SMAD4 significantly decreased the α-SMA and Vimentin levels in HF cells. Collectively, the miR-324-3p may suppress the activation of HSCs and HF by targeting SMAD4. Therefore, miR-324-3p is identified as a potential and novel therapeutic target for HF.

Role and therapeutic perspectives of extracellular vesicles derived from liver and adipose tissue in metabolic dysfunction-associated steatotic liver disease

The global epidemic of metabolic diseases has led to the emergence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH), which pose a significant threat to human health. Despite recent advances in research on the pathogenesis and treatment of MASLD/MASH, there is still a lack of more effective and targeted therapies. Extracellular vesicles (EVs) discovered in a wide range of tissues and body fluids encapsulate different activated biomolecules and mediate intercellular communication. Recent studies have shown that EVs derived from the liver and adipose tissue (AT) play vital roles in MASLD/MASH pathogenesis and therapeutics, depending on their sources and intervention types. Besides, adipose-derived stem cell (ADSC)-derived EVs appear to be more effective in mitigating MASLD/MASH. This review presents an overview of the definition, extraction strategies, and characterisation of EVs, with a particular focus on the biogenesis and release of exosomes. It also reviews the effects and potential molecular mechanisms of liver- and AT-derived EVs on MASLD/MASH, and emphasises the contribution and clinical therapeutic potential of ADSC-derived EVs. Furthermore, the future perspective of EV therapy in a clinical setting is discussed.

Targeting Autophagy for Acetaminophen-Induced Liver Injury: An Update

Acetaminophen (APAP) overdose can induce hepatocyte necrosis and acute liver failure in experimental rodents and humans. APAP is mainly metabolized via hepatic cytochrome P450 enzymes to generate the highly reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI), which forms acetaminophen protein adducts (APAP-adducts) and damages mitochondria, triggering necrosis. APAP-adducts and damaged mitochondria can be selectively removed by autophagy. Increasing evidence implies that the activation of autophagy may be beneficial for APAP-induced liver injury (AILI). In this minireview, we briefly summarize recent progress on autophagy, in particular, the pharmacological targeting of SQSTM1/p62 and TFEB in AILI.

Neutrophil extracellular traps promote acetaminophen-induced acute liver injury in mice via AIM2

Excessive acetaminophen (APAP) can induce neutrophil activation and hepatocyte death. Along with hepatocyte dysfunction and death, NETosis (a form of neutrophil-associated inflammation) plays a vital role in the progression of acute liver injury (ALI) induced by APAP overdose. It has been shown that activated neutrophils tend to migrate towards the site of injury and participate in inflammatory processes via formation of neutrophil extracellular traps (NETs). In this study we investigated whether NETs were involved in hepatocyte injury and contributed to APAP-induced ALI progression. ALI mouse model was established by injecting overdose (350 mg/kg) of APAP. After 24 h, blood and livers were harvested for analyses. We showed that excessive APAP induced multiple programmed cell deaths of hepatocytes including pyroptosis, apoptosis and necroptosis, accompanied by significantly increased NETs markers (MPO, citH3) in the liver tissue and serum. Preinjection of DNase1 (10 U, i.p.) for two consecutive days significantly inhibited NETs formation, reduced PANoptosis and consequently alleviated excessive APAP-induced ALI. In order to clarify the communication between hepatocytes and neutrophils, we induced NETs formation in isolated neutrophils, and treated HepaRG cells with NETs. We found that NETs treatment markedly increased the activation of GSDMD, caspase-3 and MLKL, while pre-treatment with DNase1 down-regulated the expression of these proteins. Knockdown of AIM2 (a cytosolic innate immune receptor) abolished NETs-induced PANoptosis in HepaRG cells. Furthermore, excessive APAP-associated ALI was significantly attenuated in AIM2KO mice, and PANoptosis occurred less frequently. Upon restoring AIM2 expression in AIM2KO mice using AAV9 virus, both hepatic injury and PANoptosis was aggravated. In addition, we demonstrated that excessive APAP stimulated mtROS production and mitochondrial DNA (mtDNA) leakage, and mtDNA activated the TLR9 pathway to promote NETs formation. Our results uncover a novel mechanism of NETs and PANoptosis in APAP-associated ALI, which might serve as a therapeutic target.

Biomarkers of Hepatic Toxicity: An Overview

Background

Hepatotoxicity is the foremost issue for clinicians and the primary reason for pharmaceutical product recalls. A biomarker is a measurable and quantifiable attribute used to evaluate the efficacy of a treatment or to diagnose a disease. There are various biomarkers which are used for the detection of liver disease and the intent of liver damage.

Objective

This review aims to investigate the current state of hepatotoxicity biomarkers and their utility in clinical settings. Using hepatic biomarkers, the presence of liver injury, its severity, prognosis, causative agent, and type of hepatotoxicity can all be determined.

Methods

Relevant published articles up to 2022 were systematically retrieved from MEDLINE/PubMed, SCOPUS, EMBASE, and WOS databases using keywords such as drug toxicity, hepatotoxicity biomarkers, biochemical parameters, and nonalcoholic fatty liver disease.

Results

In clinical trials and everyday practice, biomarkers of drug-induced liver injury are essential for spotting the most severe cases of hepatotoxicity. Hence, developing novel biomarker approaches to enhance hepatotoxicity diagnosis will increase specificity and/or identify the person at risk. Importantly, early clinical studies on patients with liver illness have proved that some biomarkers such as aminotransferase, bilirubin, albumin, and bile acids are even therapeutically beneficial.

Conclusions

By assessing the unique signs of liver injury, health care professionals can rapidly and accurately detect liver damage and evaluate its severity. These measures contribute to ensuring prompt and effective medical intervention, hence reducing the risk of long-term liver damage and other major health concerns.

The challenges and potential of microRNA-based therapy for patients with liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Morbidity and mortality from liver disease continues to rise worldwide. There are currently limited curative treatments for patients with liver failure syndromes, encompassing acute liver failure and decompensated cirrhosis states, outside of transplantation. Whilst there have been improvements in therapeutic options for patients with hepatocellular carcinoma (HCC), there remain challenges necessitating novel therapeutic agents. microRNA have long been seen as potential therapeutic targets but there has been limited clinical translation.

AREAS COVERED

We will discuss the limitations of conventional non-transplant management of patients with liver failure syndromes and HCC. We will provide an overview of microRNA and the challenges in developing and delivering microRNA-based therapeutic agents. We will finally provide an overview of microRNA-based therapeutic agents which have progressed to clinical trials.

EXPERT OPINION

microRNA have great potential to be developed into therapeutic agents due to their association with critical biological processes which govern health and disease. Utilizing microRNA sponges to target multiple microRNA associated with specific biological processes may improve their therapeutic efficacy. However, there needs to be significant improvements in delivery systems to ensure the safe delivery of microRNA to target sites and minimize systemic distribution. This currently significantly impacts the clinical translation of microRNA-based therapeutic agents.

Liver protecting effects and molecular mechanisms of icariin and its metabolites

As a detoxification and metabolism organ, the liver plays a vital role in human health. However, an excessive consumption of drugs and toxins, exposure to pathogenic viruses, and unhealthy living habits can lead to liver damage, which may even develop into liver cirrhosis and liver cancer. Epimedium brevicornum Maxim. is a traditional Chinese medicine and dietary supplement in which the flavonoid icariin is a main functional component. Although the protective mechanisms of icariin and its metabolites against liver injury are not yet comprehensively understood, an increasing number of studies have confirmed their liver-protective and anticancer effects. Indeed, icaritin, one of the metabolites of icariin, is currently utilized as an active component of an anti-cancer drug. This paper presents a review of the molecular mechanisms through which icariin and its metabolites actively protect against the occurrence and development of liver injury, and, thus, provides a comprehensive reference for further research and their application in liver protection.

The Role of MicroRNAs in Liver Functioning: from Biogenesis to Therapeutic Approaches (Review)

Molecular diagnostics based on small non-coding RNA molecules (in particular microRNA) is a new direction in modern biomedicine and is considered a promising method for identification of a wide range of pathologies at an early stage, clinical phenotype assessment, as well as monitoring the course of the disease, evaluation of therapy efficacy and the risk of the disease recurrence. Currently, the role of microRNAs as the most important epigenetic regulator in cancer development has been proven within the studies of normal and pathogenic processes. However, currently, there are insignificant studies devoted to studying the role of microRNAs in functioning of other organs and tissues, as well as to development of possible therapeutic approaches based on microRNAs. A huge number of metabolic processes in the liver are controlled by microRNAs, which creates enormous potential for the use of microRNAs as a diagnostic marker and makes it a target for therapeutic intervention in metabolic, oncological, and even viral diseases of this organ. This review examines various aspects of biological functions of microRNAs in different types of liver cells. Both canonical and non-canonical pathways of biogenesis, epigenetic regulation mediated by microRNAs, as well as the microRNAs role in intercellular communication and the course of viral diseases are shown. The potential of microRNAs as a diagnostic marker for various liver pathologies is described, as well as therapeutic approaches and medicines based on microRNAs, which are approved for clinical use and currently being developed.

MicroRNA-223 attenuates hepatocarcinogenesis by blocking hypoxia-driven angiogenesis and immunosuppression

OBJECTIVE

The current treatment for hepatocellular carcinoma (HCC) to block angiogenesis and immunosuppression provides some benefits only for a subset of patients with HCC, thus optimised therapeutic regimens are unmet needs, which require a thorough understanding of the underlying mechanisms by which tumour cells orchestrate an inflamed tumour microenvironment with significant myeloid cell infiltration. MicroRNA-223 (miR-223) is highly expressed in myeloid cells but its role in regulating tumour microenvironment remains unknown.

DESIGN

Wild-type and miR-223 knockout mice were subjected to two mouse models of inflammation-associated HCC induced by injection of diethylnitrosamine (DEN) or orthotopic HCC cell implantation in chronic carbon tetrachloride (CCl4)-treated mice.

RESULTS

Genetic deletion of miR-223 markedly exacerbated tumourigenesis in inflammation-associated HCC. Compared with wild-type mice, miR-223 knockout mice had more infiltrated programmed cell death 1 (PD-1+) T cells and programmed cell death ligand 1 (PD-L1+) macrophages after DEN+CCl4 administration. Bioinformatic analyses of RNA sequencing data revealed a strong correlation between miR-223 levels and tumour hypoxia, a condition that is well-documented to regulate PD-1/PD-L1. In vivo and in vitro mechanistic studies demonstrated that miR-223 did not directly target PD-1 and PD-L1 in immune cells rather than indirectly downregulated them by modulating tumour microenvironment via the suppression of hypoxia-inducible factor 1α-driven CD39/CD73-adenosine pathway in HCC. Moreover, gene delivery of miR-223 via adenovirus inhibited angiogenesis and hypoxia-mediated PD-1/PD-L1 activation in both HCC models, thereby hindering HCC progression.

CONCLUSION

The miR-223 plays a critical role in modulating hypoxia-induced tumour immunosuppression and angiogenesis, which may serve as a novel therapeutic target for HCC.

MicroRNA therapeutics and nucleic acid nano-delivery systems in bacterial infection: a review

Bacteria that have worked with humans for thousands of years pose a major threat to human health even today, as drug resistance has become a prominent problem. Compared to conventional drug therapy, nucleic acid-based therapies are a promising and potential therapeutic strategy for diseases in which nucleic acids are delivered through a nucleic acid delivery system to regulate gene expression in specific cells, offering the possibility of curing intractable diseases that are difficult to treat at this stage. Among the many nucleic acid therapeutic ideas, microRNA, a class of small nucleic acids with special properties, has made great strides in biology and medicine in just over two decades, showing promise in preclinical drug development. In this review, we introduce recent advances in nucleic acid delivery systems and their clinical applications, highlighting the potential of nucleic acid therapies, especially miRNAs extracted from traditional herbs, in combination with the existing set of nucleic acid therapeutic systems, to potentially open up a new line of thought in the treatment of cancer, viruses, and especially bacterial infectious diseases.

Allii Macrostemonis Bulbus: A Comprehensive Review of Ethnopharmacology, Phytochemistry and Pharmacology

The dried bulbs of Allii Macrostemonis Bulbus (AMB) are called “薤白” in China and are mainly distributed in Asia. The plant species included in the 2020 Edition of the Chinese Pharmacopoeia (ChP) are Allium macrostemon Bunge (called xiaogensuan in Chinese, A. macrostemon) and Allium chinense G. Don (called xie in Chinese, A. chinense), respectively. In the traditional Chinese medicine (TCM) theoretical system, AMB is warm in nature, acrid-bitter taste, and attributive to the heart, lung, stomach, large intestine meridian. AMB has the function of activating Yang and removing stasis, regulating Qi and eliminating stagnation. Modern pharmacological studies have shown that AMB has anti-platelet aggregation, hypolipidemic, anti-atherosclerotic, cardiomyocyte, vascular endothelial cell protection, anti-cancer, anti-bacterial, anti-asthmatic, and anti-oxidant effects. In some Asian countries, AMB is often used to treat coronary heart disease (CHD), angina pectoris (AP), asthma, and diarrhea. This review collates the botanical background, ethnopharmacology, phytochemistry, pharmacological activities, quality control, and toxicological studies of AMB, and provides an outlook on the current research deficiencies and future research priorities of AMB, intending to provide ideas for future research directions and commercial development.

Mitophagy-promoting miR-138-5p promoter demethylation inhibits pyroptosis in sepsis-associated acute lung injury

BACKGROUND

The present study was designed to explore the potential regulatory mechanism between mitophagy and pyroptosis during sepsis-associated acute lung injury (ALI).

METHODS

In vitro or in vivo models of sepsis-associated ALI were established by administering lipopolysaccharide (LPS) or performing caecal ligation and puncture (CLP) surgery. Pyroptosis levels were detected by electron microscopy, immunofluorescence, flow cytometry, western blotting and immunohistochemistry. Dual-luciferase reporter gene assay was applied to verify the targeting relationship between miR-138-5p and NLRP3. Methylation-specific PCR and chromatin immunoprecipitation assays were used to determine methylation of the miR-138-5p promoter. Mitophagy levels were examined by transmission electron microscopy and western blotting.

RESULTS

NLRP3 inflammasome silencing alleviated alveolar macrophage (AM) pyroptosis and septic lung injury. In addition, we confirmed the direct targeting relationship between miR-138-5p and NLRP3. Overexpressed miR-138-5p alleviated AM pyroptosis and the pulmonary inflammatory response. Moreover, the decreased expression of miR-138-5p was confirmed to depend on promoter methylation, while inhibition of miR-138-5p promoter methylation attenuated AM pyroptosis and pulmonary inflammation. Here, we discovered that an increased cytoplasmic mtDNA content in sepsis-induced ALI models induced the methylation of the miR-138-5p promoter, thereby decreasing miR-138-5p expression, which may activate the NLRP3 inflammasome and trigger AM pyroptosis. Mitophagy, a form of selective autophagy that clears damaged mitochondria, reduced cytoplasmic mtDNA levels. Furthermore, enhanced mitophagy might suppress miR-138-5p promoter methylation and relieve the pulmonary inflammatory response, changes that were reversed by treatment with isolated mtDNA.

CONCLUSIONS

In summary, our study indicated that mitophagy induced the demethylation of the miR-138-5p promoter, which may subsequently inhibit NLRP3 inflammasome, AM pyroptosis and inflammation in sepsis-induced lung injury. These findings may provide a promising therapeutic target for sepsis-associated ALI.

Toll-like Receptors and Thrombopoiesis

Platelets are the second most abundant blood component after red blood cells and can participate in a variety of physiological and pathological functions. Beyond its traditional role in hemostasis and thrombosis, it also plays an indispensable role in inflammatory diseases. However, thrombocytopenia is a common hematologic problem in the clinic, and it presents a proportional relationship with the fatality of many diseases. Therefore, the prevention and treatment of thrombocytopenia is of great importance. The expression of Toll-like receptors (TLRs) is one of the most relevant characteristics of thrombopoiesis and the platelet inflammatory function. We know that the TLR family is found on the surface or inside almost all cells, where they perform many immune functions. Of those, TLR2 and TLR4 are the main stress-inducing members and play an integral role in inflammatory diseases and platelet production and function. Therefore, the aim of this review is to present and discuss the relationship between platelets, inflammation and the TLR family and extend recent research on the influence of the TLR2 and TLR4 pathways and the regulation of platelet production and function. Reviewing the interaction between TLRs and platelets in inflammation may be a research direction or program for the treatment of thrombocytopenia-related and inflammatory-related diseases.

Osthole Alleviates D-Galactose-Induced Liver Injury In Vivo via the TLR4/MAPK/NF-κB Pathways

Osthole, a coumarin derivative, is found in several medicinal herbs. However, the protective effects of osthole against D-galactose (D-Gal)-induced liver injury still remain unclear. In this study, osthole treatment effectively reversed D-Gal-induced liver injury, according to the results of liver HE staining, and improved ALT and AST activities. Feeding with D-Gal significantly increased MDA content, and reduced the level or activity of SOD, CAT and GSH-Px, which were all alleviated by osthole intervention. Meanwhile, osthole treatment significantly inhibited the D-Gal-induced secretion of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6, in both serum and liver tissue. Investigations revealed that osthole ameliorated the D-Gal-induced activation of TLR4, MYD88 and its downstream signaling pathways of MAPK (p38 and JNK) and NF-κB (nucleus p65). Therefore, osthole mediates a protective effect against D-Gal-induced liver injury via the TLR4/MAPK/NF-κB pathways, and this coumarin derivative could be developed as a candidate bioactive component for functional food.

Targeting epigenetic regulators for inflammation: Mechanisms and intervention therapy

Emerging evidence indicates that resolution of inflammation is a critical and dynamic endogenous process for host tissues defending against external invasive pathogens or internal tissue injury. It has long been known that autoimmune diseases and chronic inflammatory disorders are characterized by dysregulated immune responses, leading to excessive and uncontrol tissue inflammation. The dysregulation of epigenetic alterations including DNA methylation, posttranslational modifications to histone proteins, and noncoding RNA expression has been implicated in a host of inflammatory disorders and the immune system. The inflammatory response is considered as a critical trigger of epigenetic alterations that in turn intercede inflammatory actions. Thus, understanding the molecular mechanism that dictates the outcome of targeting epigenetic regulators for inflammatory disease is required for inflammation resolution. In this article, we elucidate the critical role of the nuclear factor-κB signaling pathway, JAK/STAT signaling pathway, and the NLRP3 inflammasome in chronic inflammatory diseases. And we formulate the relationship between inflammation, coronavirus disease 2019, and human cancers. Additionally, we review the mechanism of epigenetic modifications involved in inflammation and innate immune cells. All that matters is that we propose and discuss the rejuvenation potential of interventions that target epigenetic regulators and regulatory mechanisms for chronic inflammation-associated diseases to improve therapeutic outcomes.

The Roles of MiRNAs (MicroRNAs) in Melanoma Immunotherapy

Melanoma is the most aggressive form of skin cancer, characterized by life-threatening and rapidly spreading progression. Traditional targeted therapy can alleviate tumors by inactivating hyperactive kinases such as BRAF or MEK but inevitably encounters drug resistance. The advent of immunotherapy has revolutionized melanoma treatment and significantly improved the prognosis of melanoma patients. MicroRNAs (miRNAs) are intricately involved in innate and adaptive immunity and are implicated in melanoma immunotherapy. This systematic review describes the roles of miRNAs in regulating the functions of immune cells in skin and melanoma, as well as the involvement of miRNAs in pharmacology including the effect, resistance and immune-related adverse events of checkpoint inhibitors such as PD-1 and CTLA-4 inhibitors, which are used for treating cutaneous, uveal and mucosal melanoma. The expressions and functions of miRNAs in immunotherapy employing tumor-infiltrating lymphocytes and Toll-like receptor 9 agonists are also discussed. The prospect of innovative therapeutic strategies such as the combined administration of miRNAs and immune checkpoint inhibitors and the nanotechnology-based delivery of miRNAs are also provided. A comprehensive understanding of the interplay between miRNAs and immunotherapy is crucial for the discovery of reliable biomarkers and for the development of novel miRNA-based therapeutics against melanoma.

The immunological mechanisms and therapeutic potential in drug-induced liver injury: lessons learned from acetaminophen hepatotoxicity

Acute liver failure caused by drug overdose is a significant clinical problem in developed countries. Acetaminophen (APAP), a widely used analgesic and antipyretic drug, but its overdose can cause acute liver failure. In addition to APAP-induced direct hepatotoxicity, the intracellular signaling mechanisms of APAP-induced liver injury (AILI) including metabolic activation, mitochondrial oxidant stress and proinflammatory response further affect progression and severity of AILI. Liver inflammation is a result of multiple interactions of cell death molecules, immune cell-derived cytokines and chemokines, as well as damaged cell-released signals which orchestrate hepatic immune cell infiltration. The immunoregulatory interplay of these inflammatory mediators and switching of immune responses during AILI lead to different fate of liver pathology. Thus, better understanding the complex interplay of immune cell subsets in experimental models and defining their functional involvement in disease progression are essential to identify novel therapeutic targets for the treatment of AILI. Here, this present review aims to systematically elaborate on the underlying immunological mechanisms of AILI, its relevance to immune cells and their effector molecules, and briefly discuss great therapeutic potential based on inflammatory mediators.

Platelet in thrombo-inflammation: Unraveling new therapeutic targets

In the broad range of human diseases, thrombo-inflammation appears as a clinical manifestation. Clinically, it is well characterized in context of superficial thrombophlebitis that is recognized as thrombosis and inflammation of superficial veins. However, it is more hazardous when developed in the microvasculature of injured/inflamed/infected tissues and organs. Several diseases like sepsis and ischemia-reperfusion can cause formation of microvascular thrombosis subsequently leading to thrombo-inflammation. Thrombo-inflammation can also occur in cases of antiphospholipid syndrome, preeclampsia, sickle cell disease, bacterial and viral infection. One of the major contributors to thrombo-inflammation is the loss of normal anti-thrombotic and anti-inflammatory potential of the endothelial cells of vasculature. This manifest itself in the form of dysregulation of the coagulation pathway and complement system, pathologic platelet activation, and increased recruitment of leukocyte within the microvasculature. The role of platelets in hemostasis and formation of thrombi under pathologic and non-pathologic conditions is well established. Platelets are anucleate cells known for their essential role in primary hemostasis and the coagulation pathway. In recent years, studies provide strong evidence for the critical involvement of platelets in inflammatory processes like acute ischemic stroke, and viral infections like Coronavirus disease 2019 (COVID-19). This has encouraged the researchers to investigate the contribution of platelets in the pathology of various thrombo-inflammatory diseases. The inhibition of platelet surface receptors or their intracellular signaling which mediate initial platelet activation and adhesion might prove to be suitable targets in thrombo-inflammatory disorders. Thus, the present review summarizes the concept and mechanism of platelet signaling and briefly discuss their role in sterile and non-sterile thrombo-inflammation, with the emphasis on role of platelets in COVID-19 induced thrombo-inflammation. The aim of this review is to summarize the recent developments in deciphering the role of the platelets in thrombo-inflammation and discuss their potential as pharmaceutical targets.

The immunosuppressive tumor microenvironment in hepatocellular carcinoma-current situation and outlook

Hepatocellular carcinoma (HCC) is one of the most severe malignant tumors that threaten human health, and its incidence is still on the rise recently. In spite of the current emerging treatment strategies, the overall prognosis of liver cancer remains worrying. Currently, immunotherapy has become a new research-active spot. The emergence of immune checkpoints and targeted immune cell therapy can significantly improve the prognosis of HCC. To a large extent, the effect of this immunotherapy depends on the tumor immune microenvironment (TME), an intricate system in which cancer cells and other non-cancer cells display various interactions. Understanding the immunosuppressive situation of these cells, along with the malignant behavior of cancer cells, can assist us to design new therapeutic approaches against tumors. Therefore, it is necessary to clarify the TME of HCC for further improvement of clinical treatment. This review discussed the functions of several immunosuppressive cells and exosomes in the latest research progress of HCC, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs) and tumor-associated neutrophils (TANs) interacted actively to facilitate tumor progression. It further describes the treatment methods targeting them and the potential that needs to be explored in the future.

Role of released mitochondrial DNA in acute lung injury

Acute lung injury(ALI)/acute respiratory distress syndrome(ARDS) is a form of acute-onset hypoxemic respiratory failure characterised by an acute, diffuse, inflammatory lung injury, and increased alveolar-capillary permeability, which is caused by a variety of pulmonary or nonpulmonary insults. Recently, aberrant mitochondria and mitochondrial DNA(mtDNA) level are associated with the development of ALI/ARDS, and plasma mtDNA level shows the potential to be a promising biomarker for clinical diagnosis and evaluation of lung injury severity. In mechanism, the mtDNA and its oxidised form, which are released from impaired mitochondria, play a crucial role in the inflammatory response and histopathological changes in the lung. In this review, we discuss mitochondrial outer membrane permeabilisation (MOMP), mitochondrial permeability transition pore(mPTP), extracellular vesicles (EVs), extracellular traps (ETs), and passive release as the principal mechanisms for the release of mitochondrial DNA into the cytoplasm and extracellular compartments respectively. Further, we explain how the released mtDNA and its oxidised form can induce inflammatory cytokine production and aggravate lung injury through the Toll-like receptor 9(TLR9) signalling, cytosolic cGAS-stimulator of interferon genes (STING) signalling (cGAS-STING) pathway, and inflammasomes activation. Additionally, we propose targeting mtDNA-mediated inflammatory pathways as a novel therapeutic approach for treating ALI/ARDS.

The Dual Role of Innate Immune Response in Acetaminophen-Induced Liver Injury

Acetyl-para-aminophenol (APAP), a commonly used antipyretic analgesic, is becoming increasingly toxic to the liver, resulting in a high rate of acute hepatic failure in Europe and the United States. Excessive APAP metabolism in the liver develops an APAP-protein adduct, which causes oxidative stress, MPTP opening, and hepatic necrosis. HMGB-1, HSP, nDNA, mtDNA, uric acid, and ATP are DMAPs released during hepatic necrosis. DMAPs attach to TLR4-expressing immune cells such KCs, macrophages, and NK cells, activating them and causing them to secrete cytokines. Immune cells and their secreted cytokines have been demonstrated to have a dual function in acetaminophen-induced liver injury (AILI), with a role in either proinflammation or pro-regeneration, resulting in contradicting findings and some research confusion. Neutrophils, KCs, MoMFs, NK/NKT cells, γδT cells, DCs, and inflammasomes have pivotal roles in AILI. In this review, we summarize the dual role of innate immune cells involved in AILI and illustrate how these cells initiate innate immune responses that lead to persistent inflammation and liver damage. We also discuss the contradictory findings in the literature and possible protocols for better understanding the molecular regulatory mechanisms of AILI.

The Immune Pathogenesis of Acute-On-Chronic Liver Failure and the Danger Hypothesis

Acute-on-chronic liver failure (ACLF) is a group of clinical syndromes related to severe acute liver function impairment and multiple-organ failure caused by various acute triggering factors on the basis of chronic liver disease. Due to its severe condition, rapid progression, and high mortality, it has received increasing attention. Recent studies have shown that the pathogenesis of ACLF mainly includes direct injury and immune injury. In immune injury, cytotoxic T lymphocytes (CTLs), dendritic cells (DCs), and CD4⁺ T cells accumulate in the liver tissue, secrete a variety of proinflammatory cytokines and chemokines, and recruit more immune cells to the liver, resulting in immune damage to the liver tissue, massive hepatocyte necrosis, and liver failure, but the key molecules and signaling pathways remain unclear. The “danger hypothesis” holds that in addition to the need for antigens, damage-associated molecular patterns (DAMPs) also play a very important role in the occurrence of the immune response, and this hypothesis is related to the pathogenesis of ACLF. Here, the research status and development trend of ACLF, as well as the mechanism of action and research progress on various DAMPs in ACLF, are summarized to identify biomarkers that can predict the occurrence and development of diseases or the prognosis of patients at an early stage.

miR-301a-3p promotes hepatic stellate cells activation and liver fibrogenesis via regulating PTEN/PDGFR-β

Hepatic fibrosis is an essential pathology of multiple chronicliverdiseases. The aim of this study was to investigate the role of miR-301a-3p in hepatic fibrosis. We found that miR-301a-3p was upregulated in hepatic fibrosis patients and in culture-activated human hepatic stellate cells (HSCs). Interestingly, miR-301a-3p expression was increased in hepatic fibrosis progression mice while decreased in hepatic fibrosis recovery mice, indicating that miR-301a-3p may participate in the hepatic fibrosis pathology. Functionally, the effects of miR-301a-3p both on hepatic fibrosis progression and regression were assessed in vivo. Inhibiting miR-301a-3p amelioratedmouse liver fibrogenesis and collagen deposition and suppressed HSC activation and fibrogenic factor expression. Whereas, in hepatic fibrosis regression, upregulating miR-301a-3p impaired mouse hepatic fibrosis recovery by inducing HSC activation and triggering inflammation. Consistently, gain-of-function and loss-of-function analysis of miR-301a-3p were performed to evaluate its effects on human HSCs LX-2 cell. We found that suppressing miR-301a-3p inhibited LX-2 cell activation and proliferation, and induced LX-2 cell apoptosis, accompaniedby decreased fibrotic mediators expression. Collectively, these findings suggest miR-301a-3p drives liver fibrogenesis and HSC activation in hepatic fibrosis. Mechanistically, we demonstrated miR-301a-3p binds directly to phosphatase and tensin homolog (PTEN) by luciferase reporter analysis, pull-down, and RIP assay. Indicating that miR-301a-3p plays a critical rolein promotingliverfibrogenesis viamodulating the PTEN/platelet derived growth factor β (PDGFR-β) pathway. In conclusion, our findings demonstrate that miR-301a-3p expression is closely correlated with hepatic fibrosis pathology, and that enhancing miR-301a-3p maintains the HSC profibrogenic phenotype, triggers inflammatoryresponses, promotes fibrogenic factor production, and further exacerbates liver fibrogenesis. These findings suggest that miR-301a-3p may serve as a promising diagnostic and prognosis biomarker for hepatic fibrosis treatment.

Targeting innate immune responses to attenuate acetaminophen-induced hepatotoxicity

Acetaminophen (APAP) hepatotoxicity is an important cause of acute liver failure, resulting in massive deaths in many developed countries. Currently, the metabolic process of APAP in the body has been well studied. However, the underlying mechanism of APAP-induced liver injury remains elusive. Increasing clinical and experimental evidences indicate that the innate immune responses are involved in the pathogenesis of APAP-induced acute liver injury (AILI), in which immune cells have dual roles of inducing inflammation to exacerbate hepatotoxicity and removing dead cells and debris to help liver regeneration. In this review, we summarize the latest findings of innate immune cells involved in AILI, particularly emphasizing the activation of innate immune cells and their different roles during the injury and repair phases. Moreover, current available treatments are discussed according to the different roles of innate immune cells in the development of AILI. This review aims to update the knowledge about innate immune responses in the pathogenesis of AILI, and provide potential therapeutic interventions for AILI.

Neutrophil Extracellular Traps Mediate Acute Liver Failure in Regulation of miR-223/Neutrophil Elastase Signaling in Mice

BACKGROUND & AIMS

Marked enhancement of neutrophil infiltration in the liver is a hallmark of acute liver failure (ALF), a severe life-threatening disease with varying etiologies. However, the mechanisms and pathophysiological role corresponding to hepatic neutrophil infiltration during ALF development remain poorly characterized.

METHODS

Experimental ALF was induced in 10-week-old male microRNA-223 (miR-223) knockout (KO) mice, neutrophil elastase (NE) KO mice, and wild-type controls by intraperitoneal injection of galactosamine hydrochloride and lipopolysaccharide. Age-matched mice were injected with phosphate-buffered saline and served as vehicle controls.

RESULTS

Mouse liver with ALF showed evident formation of neutrophil extracellular traps (NETs), which were enhanced markedly in miR-223 KO mice. The blockade of NETs by pharmacologic inhibitor GSK484 significantly attenuated neutrophil infiltration and massive necrosis in mouse liver with ALF. ALF-related hepatocellular damage and mortality in miR-223 KO mice were aggravated significantly and accompanied by potentiated neutrophil infiltration in the liver when compared with wild-type controls. Transcriptomic analyses showed that miR-223 deficiency in bone marrow predominantly caused the enrichment of pathways involved in neutrophil degranulation. Likewise, ALF-induced hepatic NE enrichment was potentiated in miR-223 KO mice. Genetic ablation of NE blunted the formation of NETs in parallel with significant attenuation of ALF in mice. Pharmaceutically, pretreatment with the NE inhibitor sivelestat protected mice against ALF.

CONCLUSIONS

The present study showed the miR-223/NE axis as a key modulator of NETs, thereby exacerbating oxidative stress and neutrophilic inflammation to potentiate hepatocellular damage and liver necrosis in ALF development, and offering potential targets against ALF.

Mitochondria as mediators of systemic inflammation and organ cross talk in acute kidney injury

Acute kidney injury (AKI) is a systemic inflammatory disease that contributes to remote organ failures. Multiple organ failure is the leading cause of death due to AKI, and lack of understanding of the mechanisms involved has precluded the development of novel therapies. Mitochondrial injury in AKI leads to mitochondrial fragmentation and release of damage-associated molecular patterns, which are known to active innate immune pathways and systemic inflammation. This review presents current evidence suggesting that extracellular mitochondrial damage-associated molecular patterns are mediators of remote organ failures during AKI that have the potential to be modifiable.

MiR-223 as a Regulator and Therapeutic Target in Liver Diseases

MicroRNAs (miRNAs) are endogenous non-coding single-stranded small molecule RNAs consisting of 20–24 nucleotides that are highly conserved in species evolution. Expression of miRNAs is strictly tissue-specific, and it is chronological in fungi and plants, as well as in animals. MiR-223 has been shown to play a key role in innate immunity, and dysregulation of its expression contributes to the pathogenesis of multiple inflammatory diseases, and cancers. In this article the biosynthesis and functions of miR-223 in innate immunity are reviewed, and the role of miR-223 in liver physiopathology and therapeutic prospects are highlighted.

Scavenging ROS to Alleviate Acute Liver Injury by ZnO-NiO@COOH

Currently, the incidence of acute liver injury (ALI) is increasing year by year, and infection with coronavirus disease 2019 (COVID-19) can also induce ALI, but there are still no targeted therapeutic drugs. ZnO-NiO particles is mainly used to clean up reactive oxygen species (ROS) in industrial wastewater, and it is insoluble in water. Its excellent properties are discovered and improved by adding shuttle-based bonds to make it more water-soluble. ZnO-NiO@COOH particles are synthetically applied to treat ALI. The p-n junction in ZnO-NiO@COOH increases the surface area and active sites, thereby creating large numbers of oxygen vacancies, which can quickly adsorb ROS. The content in tissues and serum levels of L-glutathione (GSH) and the GSH/oxidized GSH ratio are measured to assess the capacity of ZnO-NiO@COOH particles to absorb ROS. The ZnO-NiO@COOH particles significantly reduce the expression levels of inflammatory factors (i.e., IL-1, IL-6, and TNF-α), macrophage infiltration, and granulocyte activation. ZnO-NiO@COOH rapidly adsorb ROS in a short period of time to block the generation of inflammatory storms and gain time for the follow-up treatment of ALI, which has important clinical significance.

Role of Exosomal miR-223 in Chronic Skeletal Muscle Inflammation

As skeletal muscle is one of the largest organs in the body, its damage can directly reflect a decline in somatic function, thus, further affecting daily life and health. Inflammation is a prerequisite for the repair of injured skeletal muscles. Chronic inflammation induced by inadequate repair in skeletal muscle aggravates tissue injury. Exosomes regulate inflammatory responses to facilitate the repair of skeletal muscle injury. Moreover, exosomal miR‐223 with high specificity is the most abundant miRNA in peripheral blood and regarded as biomarkers for inflammation post skeletal muscle injury, which warrants further investigation. Available studies have demonstrated that exosomal miR‐223 negatively correlates with TNF‐α levels in serum and regulates the canonical inflammatory NF‐κB signaling pathway. miR‐223 is a negative feedback regulator with great potential for adjusting inflammatory imbalance and promoting skeletal muscle repair. The research on the regulation of negative feedback factors in the inflammatory signaling pathway is essential in biology and medicine. Therefore, this review mainly elaborates the formation, heterogeneity and markers of exosomes and points out exosomal miR‐223 as a beneficial role in chronic skeletal muscle inflammation and can be expected to be a potential therapeutic target for skeletal muscle damage.

Recent insights into the pathogeneses and therapeutic targets of liver diseases: Summary of the 4th Chinese American Liver Society/Society of Chinese Bioscientists in America Hepatology Division Symposium in 2021

The 4th Chinese American Liver Society (CALS)/Society of Chinese Bioscientists in America (SCBA) Hepatology Division Annual Symposium was held virtually on October 29-30, 2021. The goal of the CALS Symposium was to present and discuss the recent research data on the pathogeneses and therapeutic targets of liver diseases among the CALS members, trainees and invited speakers. Here we briefly introduce the history of the CALS/SCBA Hepatology Division and highlight the presentations that focus on the current progresses on basic and translational research in liver metabolism, bile acid biology, alcohol-related liver disease, drug-induced liver injury, cholestatic liver injury, non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and liver cancer.

Atractylenolide I Ameliorates Acetaminophen-Induced Acute Liver Injury via the TLR4/MAPKs/NF-κB Signaling Pathways

Background: Acetaminophen (APAP) overdose results in the production of reactive oxygen species (ROS), induces hepatocyte necrosis, and leads to acute liver failure. Atractylenolide I (AO-I), a phytochemical found in Atractylodes macrocephala Koidz, is known to exhibit antioxidant activity. However, its clinical benefits against drug-induced liver injury remain largely unclear.

Purpose: This study aimed at evaluating the protective effects of AO-I against APAP-induced acute liver injury.

Methods: C57BL/6 mice were administered 500 mg/kg APAP to induce hepatotoxicity. AO-Ⅰ (60 and 120 mg/kg) was intragastrically administered 2 h before APAP dosing. Liver histopathological changes, oxidative stress and hepatic inflammation markers from each group were observed.

Results: We observed that AO-I treatment significantly reversed APAP-induced liver injury, as evidenced by improved plasma alanine transaminase (ALT) level, aspartate aminotransferase (AST) and liver H&E stain. APAP treatment increased liver malondialdehyde (MDA) content and reduced catalase (CAT) and glutathione (GSH) level; however, these effects were alleviated by AO-I intervention. Moreover, AO-I treatment significantly inhibited APAP-induced activation of pro-inflammatory factors, such as IL-1β, IL-6, and TNF-α, at both the mRNA and protein levels. Mechanistic studies revealed that AO-I attenuated APAP-induced activation of TLR4, NF-κB and MAPKs (including JNK and p38).

Conclusion: AO-I mediates protective effects against APAP-induced hepatotoxicity via the TLR4/MAPKs/NF-κB pathways. Thus, AO-I is a candidate therapeutic compound for APAP-induced hepatotoxicity.

Immune and Metabolic Alterations in Liver Fibrosis: A Disruption of Oxygen Homeostasis?

According to the WHO, “cirrhosis of the liver” was the 11th leading cause of death globally in 2019. Many kinds of liver diseases can develop into liver cirrhosis, and liver fibrosis is the main pathological presentation of different aetiologies, including toxic damage, viral infection, and metabolic and genetic diseases. It is characterized by excessive synthesis and decreased decomposition of extracellular matrix (ECM). Hepatocyte cell death, hepatic stellate cell (HSC) activation, and inflammation are crucial incidences of liver fibrosis. The process of fibrosis is also closely related to metabolic and immune disorders, which are usually induced by the destruction of oxygen homeostasis, including mitochondrial dysfunction, oxidative stress, and hypoxia pathway activation. Mitochondria are important organelles in energy generation and metabolism. Hypoxia-inducible factors (HIFs) are key factors activated when hypoxia occurs. Both are considered essential factors of liver fibrosis. In this review, the authors highlight the impact of oxygen imbalance on metabolism and immunity in liver fibrosis as well as potential novel targets for antifibrotic therapies.

Role of caspase-8 and/or -9 as biomarkers that can distinguish the potential to cause toxic- and immune related-adverse event, for the progress of acetaminophen-induced liver injury

AIMS

Acetaminophen (APAP) overdose can cause acute liver failure. Although it is well known that APAP-induced liver injury (AILI) is caused by toxic mechanism, recently it is also reported to be immune related. However, the detail of the mechanism has been unclear. Therefore, elucidation of the pathophysiology is required.

MAIN METHODS

In AILI model rats (800 mg/kg), the levels of AST, ALT and Caspase (C)-3/-8/-9 levels were measured. In in vitro study using human hepatocyte cells (FLC-4) and THP-1 cells, APAP (1.0 mM) were added to FLC-4 and the cell viability, C-9, cytochrome c, mitochondria membrane potential, and glutathione levels of FLC-4 and inflammasome activation of THP-1 were evaluated.

KEY FINDINGS

In AILI model rats, the levels of AST and ALT were increased only at 12-24 h. C-3/-9 levels rose at 6-9 h, whereas C-8 level rose hours later, moreover, 24 h after; C-3/-8/-9 levels re-rose. In FLC-4 cells, cytochrome c was released from the mitochondria which is promoted by oxidative stress due to drug metabolism and C-9 was activated. Thus, AILI was caused mitochondrial damage by NAPQI as early reaction (first stage). In the next stage, inflammasomes of human antigen presenting cells, which released inflammatory cytokines were activated by damage-associated molecular patterns (DAMPs) released from damaged hepatocyte by APAP.

SIGNIFICANCE

It is confirmed that AILI includes immune related mechanism. Thereby, in case of N-acetylcysteine refractory, additional administration of steroid hormones should be effective and recommended as a novel strategy for AILI with immune related adverse event (irAE).

The role of MLKL in Hepatic Ischemia-Reperfusion Injury of Alcoholic Steatotic Livers

Alcohol-related liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the primary causes of chronic liver disease in western countries. Liver transplantation is currently one of the most efficient approaches to save patients with liver failure, which is often associated with hepatic ischemia-reperfusion (IR) injury. IR injury is exacerbated by hepatic steatosis, yet the mechanism remains elusive. Necroptosis is a form of regulated cell death mediated by receptor-interacting protein kinase 1 (RIP1), RIP3 and mixed lineage kinase domain-like (MLKL) protein, which has been implicated in the pathogenesis of ALD and NAFLD. Though necroptosis plays an important role in IR injury of high fat diet - induced steatotic livers, the role of necroptosis in IR injury of ethanol - induced steototic livers has not been investigated. In the present study, we used chronic plus binge alcohol (Gao-binge) feeding followed by IR surgery to investigate IR liver injury with ethanol-associated steatosis. We found that the levels of key necroptotic proteins MLKL and RIP3 increased in alcohol-fed mouse livers. Moreover, we observed increased liver injury after IR in control diet-fed mice, which was further exacerbated by alcohol feeding based on serum alanine aminotransferase (ALT) levels and TUNEL staining of necrotic cells. Hepatic neutrophil infiltration also increased in alcohol-fed mice after IR surgery. However, deletion of Mlkl did not protect against IR liver injury in alcohol-fed mice compared with matched wild-type mice. In conclusion, alcoholic steatosis promotes IR injury, which seems to be independent of MLKL-mediated necroptosis.

miR-223: An Immune Regulator in Infectious Disorders

MicroRNAs (miRNAs) are diminutive noncoding RNAs that can influence disease development and progression by post-transcriptionally regulating gene expression. The anti-inflammatory miRNA, miR-223, was first identified as a regulator of myelopoietic differentiation in 2003. This miR-223 exhibits multiple regulatory functions in the immune response, and abnormal expression of miR-223 is shown to be associated with multiple infectious diseases, including viral hepatitis, human immunodeficiency virus type 1 (HIV-1), and tuberculosis (TB) by influencing neutrophil infiltration, macrophage function, dendritic cell (DC) maturation and inflammasome activation. This review summarizes the current understanding of miR-223 physiopathology and highlights the molecular mechanism by which miR-223 regulates immune responses to infectious diseases and how it may be targeted for diagnosis and treatment.

Dual roles of p62/SQSTM1 in the injury and recovery phases of acetaminophen-induced liver injury in mice

Acetaminophen (APAP) overdose can induce liver injury and is the most frequent cause of acute liver failure in the United States. We investigated the role of p62/SQSTM1 (referred to as p62) in APAP-induced liver injury (AILI) in mice. We found that the hepatic protein levels of p62 dramatically increased at 24 h after APAP treatment, which was inversely correlated with the hepatic levels of APAP-adducts. APAP also activated mTOR at 24 h, which is associated with increased cell proliferation. In contrast, p62 knockout (KO) mice showed increased hepatic levels of APAP-adducts detected by a specific antibody using Western blot analysis but decreased mTOR activation and cell proliferation with aggravated liver injury at 24 h after APAP treatment. Surprisingly, p62 KO mice recovered from AILI whereas the wild-type mice still sustained liver injury at 48 h. We found increased number of infiltrated macrophages in p62 KO mice that were accompanied with decreased hepatic von Willebrand factor (VWF) and platelet aggregation, which are associated with increased cell proliferation and improved liver injury at 48 h after APAP treatment. Our data indicate that p62 inhibits the late injury phase of AILI by increasing autophagic selective removal of APAP-adducts and mitochondria but impairs the recovery phase of AILI likely by enhancing hepatic blood coagulation.

miRNA-223 Suppresses Mouse Gallstone Formation by Targeting Key Transporters in Hepatobiliary Cholesterol Secretion Pathway

miRNA-223 has been previously reported to play an essential role in hepatic cholesterol homeostasis. However, its role in regulation of biliary cholesterol secretion and gallstone formation remains unknown. Hence, mice with conventional knockout (KO), hepatocyte-specific knockout (ΔHepa) / knockdown (KD) or gain expression of miRNA-223 were included in the study and were subjected to lithogenic diet (LD) for various weeks. The gall bladders and liver tissues were harvested for cholesterol crystal imaging, gallstone mass measurement and molecular analysis. Levels of cholesterol, bile salt, phospholipids, and triglyceride were determined in serum, liver tissues, and bile by enzyme color reactive assays. A 3' UTR reporter gene assay was used to verify the direct target genes for miRNA-223. LD-induced gallstone formation was remarkably accelerated in miRNA-223 KO, ΔHepa, and KD mice with concurrent enhancement in total cholesterol levels in liver tissues and bile. Key biliary cholesterol transporters ABCG5 and ABCG8 were identified as direct targets of miRNA-223. Reversely, AAV-mediated hepatocyte-specific miRNA-223 overexpression prevented gallstone progression with reduced targets expression. Therefore, the present study demonstrates a novel role of miRNA-223 in the gallstone formation by targeting ABCG5 and ABCG8 and elevating miRNA-223 would be a potentially novel approach to overcome the sternness of cholesterol gallstone disease.

CD5L deficiency attenuate acetaminophen-induced liver damage in mice via regulation of JNK and ERK signaling pathway

CD5 molecule like (CD5L), a member of the scavenger receptor cysteine-rich domain superfamily, plays a critical role in immune homeostasis and inflammatory disease. Acetaminophen (APAP) is a safe and effective antipyretic analgesic. However, overdose may cause liver damage or even liver failure. APAP hepatotoxicity is characterized by extensive necrotic cell death and a sterile inflammatory response, in which the role of CD5L remains to be investigated. In this study, we found that the expression of CD5L was increased in the livers of mice after APAP overdose. Furthermore, CD5L deficiency reduced the increase of alanine transaminase (ALT) level, histopathologic lesion area, c-Jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK) phosphorylation level, Transferase-Mediated dUTP Nick End-Labeling positive (TUNEL⁺) cells proportion, vascular endothelial cell permeability and release of inflammatory cytokines induced by excess APAP. Therefore, our findings reveal that CD5L may be a potential therapeutic target for prevention and treatment of APAP-induced liver injury.

STING-mediated inflammation contributes to Gao binge ethanol feeding model

Alcohol metabolism causes hepatocytes to release damage‐associated molecular patterns (DAMPs). This includes mitochondrial DNA (mtDNA), which is generated and released from damaged hepatocytes and contributes to liver injury by producing proinflammatory cytokines. STING is a pattern recognition receptor of DAMPs known to control the induction of innate immunity in various pathological processes. However, the expression profile and functions of STING in the Gao binge ethanol model remain poorly understood. We demonstrated that STING is upregulated in the Gao binge ethanol model. STING functions as an mtDNA sensor in the Kupffer cells of the liver and induces STING‐signaling pathway‐dependent inflammation and further aggravates hepatocyte apoptosis in the Gao binge ethanol model. This study provides novel insights into predicting disease progression and developing targeted therapies for alcoholic liver injury.