MicroRNA 181b-3p and its target importin α5 regulate toll-like receptor 4 signaling in Kupffer cells and liver injury in mice in response to ethanol

The role of gut microbiota, exosomes, and their interaction in the pathogenesis of ALD

BACKGROUND

The liver disorders caused by alcohol abuse are termed alcoholic-related liver disease (ALD), including alcoholic steatosis, alcoholic steatohepatitis alcoholic hepatitis, and alcoholic cirrhosis, posing a significant threat to human health. Currently, ALD pathogenesis has not been completely clarified, which is likely to be related to the direct damage caused by alcohol and its metabolic products, oxidative stress, gut dysbiosis, and exosomes.

AIMS

The existing studies suggest that both the gut microbiota and exosomes contribute to the development of ALD. Moreover, there exists an interaction between the gut microbiota and exosomes. We discuss whether this interaction plays a role in the pathogenesis of ALD and whether it can be a potential therapeutic target for ALD treatment.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Chronic alcohol intake alters the diversity and composition of gut microbiota, which greatly contributes to ALD's progression. Some approaches targeting the gut microbiota, including probiotics, fecal microbiota transplantation, and phage therapy, have been confirmed to effectively ameliorate ALD in many animal experiments and/or several clinical trials. In ALD, the levels of exosomes and the expression profile of microRNA have also changed, which affects the pathogenesis of ALD. Moreover, there is an interplay between exosomes and the gut microbiota, which also putatively acts as a pathogenic factor of ALD.

Past, Present, and Future Therapies for Alcohol-associated Hepatitis

PURPOSE

Alcohol-associated hepatitis (AH) is a unique presentation of cholestatic steatohepatitis with liver dysfunction and malaise preceded by heavy alcohol intake. Although AH exists on a spectrum, in its most severe form, 28-day mortality approaches 50%. Clinical trials of therapeutic interventions over the last 50 years have yielded few durable therapies, none of which convey benefit beyond the short term.

METHODS

A qualitative systematic review was performed via searches of PubMed, the International Clinical Trials Registry Platform, and ClinicalTrials.gov for therapeutic interventions for AH.

FINDINGS

Prior to 2005, clinical trial results for AH were identified within PubMed. From 2005 to the present, trials were well catalogued within online registries and included information regarding trial status (eg, complete, terminated, actively enrolling). Most clinical trials for AH have used existing medications broadly targeting pathogenic themes of AH (eg, inflammation, cell death) in an off-label manner. The trend of initially promising pilot studies answered by larger trials showing lack of efficacy or safety signals have ended the hopes of many new therapeutics. The emergence of theragnostics to identify patients who may benefit from existing therapies and trials of agents with novel mechanisms of action, including epigenetic modifications and hyaluronic acid signaling targeted to AH pathogenesis, are currently under investigation.

IMPLICATIONS

This review of AH treatments details the historical interventions and clinical trials that have led to the current treatment algorithm and active studies shaping the therapeutic pipeline for AH.

MiRNAs in Alcohol-Related Liver Diseases and Hepatocellular Carcinoma: A Step toward New Therapeutic Approaches?

Alcohol-related Liver Disease (ALD) is the primary cause of chronic liver disorders and hepatocellular carcinoma (HCC) development in developed countries and thus represents a major public health concern. Unfortunately, few therapeutic options are available for ALD and HCC, except liver transplantation or tumor resection for HCC. Deciphering the molecular mechanisms underlying the development of these diseases is therefore of major importance to identify early biomarkers and to design efficient therapeutic options. Increasing evidence indicate that epigenetic alterations play a central role in the development of ALD and HCC. Among them, microRNA importantly contribute to the development of this disease by controlling the expression of several genes involved in hepatic metabolism, inflammation, fibrosis, and carcinogenesis at the post-transcriptional level. In this review, we discuss the current knowledge about miRNAs' functions in the different stages of ALD and their role in the progression toward carcinogenesis. We highlight that each stage of ALD is associated with deregulated miRNAs involved in hepatic carcinogenesis, and thus represent HCC-priming miRNAs. By using in silico approaches, we have uncovered new miRNAs potentially involved in HCC. Finally, we discuss the therapeutic potential of targeting miRNAs for the treatment of these diseases.

Post-translational modifications of histone and non-histone proteins in epigenetic regulation and translational applications in alcohol-associated liver disease: Challenges and research opportunities

Epigenetic regulation is a process that takes place through adaptive cellular pathways influenced by environmental factors and metabolic changes to modulate gene activity with heritable phenotypic variations without altering the DNA sequences of many target genes. Epigenetic regulation can be facilitated by diverse mechanisms: many different types of post-translational modifications (PTMs) of histone and non-histone nuclear proteins, DNA methylation, altered levels of noncoding RNAs, incorporation of histone variants, nucleosomal positioning, chromatin remodeling, etc. These factors modulate chromatin structure and stability with or without the involvement of metabolic products, depending on the cellular context of target cells or environmental stimuli, such as intake of alcohol (ethanol) or Western-style high-fat diets. Alterations of epigenetics have been actively studied, since they are frequently associated with multiple disease states. Consequently, explorations of epigenetic regulation have recently shed light on the pathogenesis and progression of alcohol-associated disorders. In this review, we highlight the roles of various types of PTMs, including less-characterized modifications of nuclear histone and non-histone proteins, in the epigenetic regulation of alcohol-associated liver disease (ALD) and other disorders. We also describe challenges in characterizing specific PTMs and suggest future opportunities for basic and translational research to prevent or treat ALD and many other disease states.

Karyopherin Subunit Alpha 1 Enhances the Malignant Behaviors of Colon Cancer Cells via Promoting Nuclear Factor-κB p65 Nuclear Translocation

BACKGROUND/AIMS

Aberrant nuclear factor-κB p65 (NF-κB p65) nuclear import commonly occurs in multiple cancers, including colon cancer. According to BioGRID, we noted that Karyopherin subunit alpha 1 (KPNA1), an important molecular transporter between the nucleus and the cytoplasm, may interact with NF-κB p65. KPNA1 itself is highly expressed in colon adenocarcinoma samples (N = 286) based on The Cancer Genome Atlas (TCGA) database. We aimed to explore the role of KPNA1 in colonic carcinogenesis and to determine whether NF-κB p65 nuclear translocation was involved.

METHODS

KPNA1 expressions at mRNA and protein levels were analyzed in colon cancer tissues. The regulatory effect of KPNA1 on malignant biological properties was detected in SW480 and HCT116 colon cancer cells. Coimmunoprecipitation and immunofluorescence were performed to verify the relationship between KPNA1 and NF-κB p65. KPNA1 ubiquitination was also preliminarily investigated.

RESULTS

KPNA1 was firstly confirmed as a significantly upregulated gene in our collected clinical colon cancer samples (N = 35). KPNA1 depletion inhibited cell proliferation, induced cell cycle arrest, and diminished migratory and invasive capacity of SW480 and HCT116 cells. Colon cancer cells overexpressing KPNA1 acquired more aggressive behaviors. KPNA1 acted as a transporter to induce the nuclear accumulation of NF-κB p65, thereby activating NF-κB signaling pathway in colon cancer cells. Furthermore, HECT, C2, and WW Domain-Containing E3 Ubiquitin (HECW2) interacted with KPNA1 to induce its ubiquitination. KPNA1 labeled with polyubiquitins was degraded through ubiquitin-proteasome system.

CONCLUSION

The present study uncovers a role of KPNA1-NF-κB p65 axis in promoting colonic carcinogenesis.

Hyaluronan in liver fibrosis: basic mechanisms, clinical implications, and therapeutic targets

Hyaluronan (HA), also known as hyaluronic acid, is a glycosaminoglycan that is a critical component of the extracellular matrix (ECM). Production and deposition of ECM is a wound-healing response that occurs during chronic liver disease, such as cirrhosis. ECM production is a sign of the disease progression of fibrosis. Indeed, the accumulation of HA in the liver and elevated serum HA levels are used as biomarkers of cirrhosis. However, recent studies also suggest that the ECM, and HA in particular, as a functional signaling molecule, facilitates disease progression and regulation. The systemic and local levels of HA are regulated by de novo synthesis, cleavage, endocytosis, and degradation of HA, and the molecular mass of HA influences its pathophysiological effects. However, the regulatory mechanisms of HA synthesis and catabolism and the functional role of HA are still poorly understood in liver fibrosis. This review summarizes the role of HA in liver fibrosis at molecular levels as well as its clinical implications and discusses the potential therapeutic uses of targeting HA in liver fibrosis.

The role of miRNAs in liver diseases: Potential therapeutic and clinical applications

MicroRNAs (miRNAs) are a class of short, non-coding RNAs that function post-transcriptionally to regulate gene expression by binding to particular mRNA targets and causing destruction of the mRNA or translational inhibition of the mRNA. The miRNAs control the range of liver activities, from the healthy to the unhealthy. Considering that miRNA dysregulation is linked to liver damage, fibrosis, and tumorigenesis, miRNAs are a promising therapeutic strategy for the evaluation and treatment of liver illnesses. Recent findings on the regulation and function of miRNAs in liver diseases are discussed, with an emphasis on miRNAs that are highly expressed or enriched in hepatocytes. Alcohol-related liver illness, acute liver toxicity, viral hepatitis, hepatocellular carcinoma, liver fibrosis, liver cirrhosis, and exosomes in chronic liver disease all emphasize the roles and target genes of these miRNAs. We briefly discuss the function of miRNAs in the etiology of liver diseases, namely in the transfer of information between hepatocytes and other cell types via extracellular vesicles. Here we offer some background on the use of miRNAs as biomarkers for the early prognosis, diagnosis, and assessment of liver diseases. The identification of biomarkers and therapeutic targets for liver disorders will be made possible by future research into miRNAs in the liver, which will also help us better understand the pathogeneses of liver diseases.

Recent Advances in Understanding of Pathogenesis of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is one of the major diseases arising from chronic alcohol consumption and is one of the most common causes of liver-related morbidity and mortality. ALD includes asymptomatic liver steatosis, fibrosis, cirrhosis, and alcohol-associated hepatitis and its complications. The progression of ALD involves complex cell-cell and organ-organ interactions. We focus on the impact of alcohol on dysregulation of homeostatic mechanisms and regulation of injury and repair in the liver. In particular, we discuss recent advances in understanding the disruption of balance between programmed cell death and prosurvival pathways, such as autophagy and membrane trafficking, in the pathogenesis of ALD. We also summarize current understanding of innate immune responses, liver sinusoidal endothelial cell dysfunction and hepatic stellate cell activation, and gut-liver and adipose-liver cross talk in response to ethanol. In addition,we describe the current potential therapeutic targets and clinical trials aimed at alleviating hepatocyte injury, reducing inflammatory responses, and targeting gut microbiota, for the treatment of ALD.

Emerging Pharmacotherapies in Alcohol-Associated Hepatitis

The incidence of alcoholic-associated hepatitis (AH) is increasing. The treatment options for severe AH (sAH) are scarce and limited to corticosteroid therapy which showed limited mortality benefit in short-term use only. Therefore, there is a dire need for developing safe and effective therapies for patients with sAH and to improve their high mortality rates.This review article focuses on the current novel therapeutics targeting various mechanisms in the pathogenesis of alcohol-related hepatitis. Anti-inflammatory agents such as IL-1 inhibitor, Pan-caspase inhibitor, Apoptosis signal-regulating kinase-1, and CCL2 inhibitors are under investigation. Other group of agents include gut-liver axis modulators, hepatic regeneration, antioxidants, and Epigenic modulators. We describe the ongoing clinical trials of some of the new agents for alcohol-related hepatitis.

Conclusion

A combination of therapies was investigated, possibly providing a synergistic effect of drugs with different mechanisms. Multiple clinical trials of novel therapies in AH remain ongoing. Their result could potentially make a difference in the clinical course of the disease. DUR-928 and granulocyte colony-stimulating factor had promising results and further trials are ongoing to evaluate their efficacy in the large patient sample.

Pathogenesis of Alcohol-Associated Liver Disease

Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.

Use of radiolabeled hyaluronic acid for preclinical assessment of inflammatory injury and acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is accompanied by a dramatic increase in lung hyaluronic acid (HA), leading to a dose-dependent reduction of pulmonary oxygenation. This pattern is associated with severe infections, such as COVID-19, and other important lung injury etiologies. HA actively participates in molecular pathways involved in the cytokine storm of COVID-19-induced ARDS. The objective of this study was to evaluate an imaging approach of radiolabeled HA for assessment of dysregulated HA deposition in mouse models with skin inflammation and lipopolysaccharide (LPS)-induced ARDS using a novel portable intensified Quantum Imaging Detector (iQID) gamma camera system.

METHODS

HA of 10 kDa molecular weight (HA10) was radiolabeled with 125I and 99mTc respectively to produce [125I]I-HA10 and [99mTc]Tc-HA10, followed by comparative studies on stability, in vivo biodistribution, and uptake at inflammatory skin sites in mice with 12-O-tetradecanoylphorbol-13-acetate (TPA)-inflamed ears. [99mTc]Tc-HA10 was used for iQID in vivo dynamic imaging of mice with ARDS induced by intratracheal instillation of LPS.

RESULTS

[99mTc]Tc-HA10 and [125I]I-HA10 had similar biodistribution and localization at inflammatory sites. [99mTc]Tc-HA10 was shown to be feasible in measuring skin injury and monitoring skin wound healing. [99mTc]Tc-HA10 dynamic pulmonary images yielded good visualization of radioactive uptake in the lungs. There was significantly increased lung uptake and slower lung washout in mice with LPS-induced ARDS than in control mice. Postmortem biodistribution measurement of [99mTc]TcHA10 (%ID/g) was 11.0 ± 3.9 vs. 1.3 ± 0.3 in the ARDS mice (n = 6) and controls (n = 6) (P < 0.001), consistent with upregulated HA expression as determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) staining.

CONCLUSIONS

[99mTc]Tc-HA10 is promising as a biomarker for evaluating HA dysregulation that contributes to pulmonary injury in ARDS. Rapid iQID imaging of [99mTc]Tc-HA10 clearance from injured lungs may provide a functional template for timely assessment and quantitative monitoring of pulmonary pathophysiology and intervention in ARDS.

Impact of acute schistosomiasis mansoni and long-term ethanol intake on mouse liver pathology

While the effect of ethanol and schistosomiasis mansoni on liver injury has been well-documented, the influence of comorbidity on liver pathology remains unclear. To address this gap, schistosomiasis-infected mice were given one daily dose of 18% ethanol for 28 consecutive days, from day 35 post-infection. Mice were assigned to four groups: A. control; B. uninfected/ethanol gavage; C. infected; and D. infected/ethanol gavage. At day 64 post-infection, mice were euthanized by CO₂ asphyxiation, livers were excised, fixed in 10% buffered formalin, paraffin embedded and cut into 5 μm sections. These were stained with hematoxylin and eosin (HE), Lennert's Giemsa and picrosirius red (for polarization microscopy) to assess histopathological and stereological changes. Group B showed alcoholic liver disease (ALD), including microsteatosis, hepatocyte karyopyknosis, karyorrhexis, karyolysis, increased frequency of Kupffer cells, hydropic degeneration of hepatocyte, thickened plasma membrane and binucleated hepatocytes. Infected mice showed typical exudative and exudative-productive hepatic granulomas, and destruction of the adjacent hepatic parenchyma, resulting in necrotic tissue and periovular leukocyte infiltrate. Group D showed hyperemia (parenchymal panlobular lesions), and liquefactive necrosis in hepatic abscess area. There was also reduced liver collagen deposition (-76%; p = 0.0001) and reduced microsteatosis (-80%, p = 0.0079) compared to group C and group B, respectively. In conclusion, comorbidity exacerbated liver damage.

miR-505-5p alleviates acute rejection of liver transplantation by inhibiting Myd88 and inducing M2 polarizationof Kupffer cells

The occurrence of acute rejection after liver transplantation seriously impairs the prognosis of patients. miRNA is involved in many physiological and pathological processes of the body, but the mechanism of miRNA action in liver transplantation is not completely clear. In this study, we discuss the role of miR-505-5p in acute rejection after liver transplantation and its putative regulating mechanism. We construct an allogeneic rat liver transplantation model, observe the morphological and pathological changes in liver tissue, detect the expression levels of Myd88, miR-505-5p, IL-10 and TNF-α, and confirm that Myd88 is one of the direct targets of miR-505. The effects of miR-505-5p on the Myd88/TRAF6/NF-κB and MAPK pathways are detected both in vitro and in vivo, and the standard markers of Kupffer cell M1/M2 polarization are also detected. The results of qRT-PCR experiments show that miR-505-5p has a downward trend in rats with acute rejection. Western blot analysis reveals that over-expression of miR-505-5p induces the reduction of NF-κB and MAPK pathways both in vitro and in vivo. The role of miR-505-5p in alleviating acute rejection after transplantation may be accomplished by inducing M2-type polarization of Kupffer cells. In conclusion, we find that miR-505-5p alleviates acute rejection of liver transplantation by inducing M2 polarization of macrophages via the Myd88/TRAF6 axis, which suggests a potential strategy based on miRNAs in the follow-up treatment of liver transplantation.

miR-29c-3p promotes alcohol dehydrogenase gene cluster expression by activating an ADH6 enhancer

Alcohol dehydrogenases (ADHs) play vital roles in alcohol metabolism and alcohol toxicity, yet little is known about microRNA-mediated regulation of the ADH gene cluster. Here, we showed that miR-29c activated ADH gene cluster transcription by targeting an enhancer element within the ADH6 gene. miR-29c is differentially expressed in alcoholic liver disease. Following biochemical and molecular evidence demonstrated that miR-29c increased ADH6 mRNA and protein levels without affecting the stability of the ADH6 transcript. Further evidence showed that exogenous miR-29c translocated into the nucleus and then unconventionally bound an enhancer element within the ADH6 gene. Luciferase reporter assay and chromatin immunoprecipitation data indicated that miR-29c activated the enhancer and increased the enrichment of RNA polymerase II at the promoter regions of ADH1A, ADH1B, ADH1C, ADH4, and ADH6. Finally, exogenous miR-29c transfection promoted the expression of ADH1A, ADH1B, ADH1C, and ADH4 pre-mRNA and mRNA transcripts from the ADH gene cluster. In conclusion, our data suggest that miR-29c might be a novel epigenetic regulator involved in ADH gene cluster activation.

Review article: current and emerging therapies for acute alcohol-associated hepatitis

BACKGROUND

Alcohol-associated hepatitis is an acute manifestation of alcohol-associated liver disease (ALD) and is associated with 30%-40% mortality at 28 days. Abstinence and corticosteroids are the mainstays of treatment, but the latter only improves short-term mortality, so new and improved therapies remain an unmet need.

AIMS

The aim was to review the pathophysiology of alcohol-associated hepatitis and how various targets can be used by current and emerging therapies as treatment.

METHODS

A thorough literature review was conducted on acute alcohol-associated hepatitis, current therapies and therapies under investigation.

RESULTS

With the increasing prevalence of alcohol use disorder and ALD, the burden of alcohol-associated hepatitis is also expected to rise. The current understanding of alcohol-associated hepatitis pathophysiology has led to clinical trials of several therapies involving IL-1 antagonism, modification of the gut microbiome and liver regeneration.

CONCLUSIONS

Corticosteroid therapy for alcohol-associated hepatitis is restricted in its applicability and has limited efficacy. Developing multidisciplinary, patient-centred care models based on digital health technologies, in combination with continued discovery of novel therapies using multiomics data and computational biology techniques will be necessary to tackle the increasing burden of alcohol-associated hepatitis.

Epigenetics of alcohol-related liver diseases

Alcohol-related liver disease (ARLD) is a primary cause of chronic liver disease in the United States. Despite advances in the diagnosis and management of ARLD, it remains a major public health problem associated with significant morbidity and mortality, emphasising the need to adopt novel approaches to the study of ARLD and its complications. Epigenetic changes are increasingly being recognised as contributing to the pathogenesis of multiple disease states. Harnessing the power of innovative technologies for the study of epigenetics (e.g., next-generation sequencing, DNA methylation assays, histone modification profiling and computational techniques like machine learning) has resulted in a seismic shift in our understanding of the pathophysiology of ARLD. Knowledge of these techniques and advances is of paramount importance for the practicing hepatologist and researchers alike. Accordingly, in this review article we will summarise the current knowledge about alcohol-induced epigenetic alterations in the context of ARLD, including but not limited to, DNA hyper/hypo methylation, histone modifications, changes in non-coding RNA, 3D chromatin architecture and enhancer-promoter interactions. Additionally, we will discuss the state-of-the-art techniques used in the study of ARLD (e.g. single-cell sequencing). We will also highlight the epigenetic regulation of chemokines and their proinflammatory role in the context of ARLD. Lastly, we will examine the clinical applications of epigenetics in the diagnosis and management of ARLD.

MicroRNA-29b ameliorates hepatic inflammation via suppression of STAT3 in alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is induced by chronic excessive alcohol consumption resulting in the clinical manifestations of steatosis, inflammation, and cirrhosis. MicroRNA-29b (miR-29b) is mainly expressed in hepatic nonparenchymal cells, and its expression level varies in different diseases. In this study, we aimed to determine the role of miR-29b in a mouse model of alcohol-associated liver disease. Wild-type (WT) and miR-29b knockout (miR-29b^-/-) mice were fed a Lieber-DeCarli liquid diet containing 5% alcohol for 10 days, followed by gavage of a single dose of ethanol (5 g/kg body weight). Histology, immunoblotting, and biochemical analyses were then conducted for comparison. miR-29b expression was decreased in the livers of chronic-plus-binge ethanol-fed mice. Further analysis revealed that alcohol exposure exacerbated hepatic injury by significantly increasing serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, with decreased survival rates for miR-29b^-/- mice. Results from the luciferase assay indicated that miR-29b negatively regulated the signal transducer and activator of transcription 3 (STAT3). Depletion of miR-29b led to an increase in STAT3 and more noticeable inflammation in the liver, whereas overexpression of miR-29b downregulated STAT3 and proinflammatory cytokine expression in primary mouse peritoneal macrophages. Taken together, these results demonstrate a novel association between miR-29b and ALD. miR-29b plays a hepatoprotective role in alcohol-induced inflammation and liver injury by targeting STAT3.

Transcriptional and Epigenetic Regulation of Monocyte and Macrophage Dysfunction by Chronic Alcohol Consumption

Drinking alcohol, even in moderation, can affect the immune system. Studies have shown disproportionate effects of alcohol on circulating and tissue-resident myeloid cells (granulocytes, monocytes, macrophages, dendritic cells). These cells orchestrate the body's first line of defense against microbial challenges as well as maintain tissue homeostasis and repair. Alcohol's effects on these cells are dependent on exposure pattern, with acute drinking dampening but chronic drinking enhancing production of inflammatory mediators. Although chronic drinking is associated with heightened systemic inflammation, studies on tissue resident macrophage populations in several organs including the spleen, liver, brain, and lung have also shown compromised functional and metabolic capacities of these cells. Many of these effects are thought to be mediated by oxidative stress caused by alcohol and its metabolites which can directly impact the cellular epigenetic landscapes. In addition, since myeloid cells are relatively short-lived in circulation and are under constant repopulation from the bone marrow compartment, alcohol's effects on bone marrow progenitors and hematopoiesis are important for understanding the impact of alcohol systemically on these myeloid populations. Alcohol-induced disruption of progenitor, circulating, and tissue resident myeloid populations contribute to the increased susceptibility of patients with alcohol use disorders to viral and bacterial infections. In this review, we provide an overview of the impact of chronic alcohol consumption on the function of monocytes and macrophages in host defense, tissue repair and inflammation. We then summarize our current understanding of the mechanisms underlying alcohol-induced disruption and examine changes in transcriptome and epigenome of monocytes and mcrophages. Overall, chronic alcohol consumption leads to hyper-inflammation concomitant with decreased microbial and wound healing responses by monocytes/macrophages due to a rewiring of the epigentic and transcriptional landscape. However, in advanced alcoholic liver disease, myeloid cells become immunosuppressed as a response to the surrounding hyper-inflammatory milieu. Therefore, the effect of chronic alcohol on the inflammatory response depends on disease state and the immune cell population.

Inflammatory Biomarkers in Addictive Disorders

Substance use disorders are a group of diseases that are associated with social, professional, and family impairment and that represent a high socio-economic impact on the health systems of countries around the world. These disorders present a very complex diagnosis and treatment regimen due to the lack of suitable biomarkers supporting the correct diagnosis and classification and the difficulty of selecting effective therapies. Over the last few years, several studies have pointed out that these addictive disorders are associated with systemic and central nervous system inflammation, which could play a relevant role in the onset and progression of these diseases. Therefore, identifying different immune system components as biomarkers of such addictive disorders could be a crucial step to promote appropriate diagnosis and treatment. Thus, this work aims to provide an overview of the immune system alterations that may be biomarkers of various addictive disorders.

miR-103a-3p Could Attenuate Sepsis-Induced Liver Injury by Targeting HMGB1

The liver is one of the most vulnerable organs during sepsis. Current studies have proven that microRNAs play important roles in injury and inflammation. The current study aimed to investigate the role of miR-103 in septic liver injury. The sepsis model was established by cecal ligation and puncture in mice. Then, the mice were divided into four groups: normal group, sepsis group, sepsis + miR-103a-3p agomir group, and sepsis + negative control group. Liver injury was observed by hematoxylin-eosin staining and electron microscopic studies. The sepsis-induced apoptosis in liver tissues was assessed by TUNEL staining. The levels of inflammatory cytokines in liver tissues were determined by enzyme-linked immunosorbent assay kits. The targeted gene of miR-103a-3p in cells was predicted by bioinformatics algorithm and confirmed by dual-luciferase reporter assay. The expression of miR-103a-3p, HMBG1, and the apoptosis-relative proteins was examined by quantitative real-time polymerase chain reaction and Western blotting. miR-103a-3p was downregulated in liver tissues of sepsis animals. miR-103a-3p agomir could alleviate liver injury including the tissue injury and mitochondrial damage, inhibit the secretion of inflammatory factors, and decrease the apoptosis of liver cells. The high-mobility group B1 (HMGB1) was overregulated in sepsis, and it was a downstream target gene of miR-103a-3p. The results of the rescue assay confirmed that miR-103a-3p had a protection role in septic liver injury by targeting HMGB1. In summary, HMGB1 was one of the genes targeted by miR-103a-3p, which played roles in septic injury. These data may provide novel insight for the identification of new target and treatment strategies for septic liver injury.

Alcohol's Impact on the Gut and Liver

Alcohol is inextricably linked with the digestive system. It is absorbed through the gut and metabolised by hepatocytes within the liver. Excessive alcohol use results in alterations to the gut microbiome and gut epithelial integrity. It contributes to important micronutrient deficiencies including short-chain fatty acids and trace elements that can influence immune function and lead to liver damage. In some people, long-term alcohol misuse results in liver disease progressing from fatty liver to cirrhosis and hepatocellular carcinoma, and results in over half of all deaths from chronic liver disease, over half a million globally per year. In this review, we will describe the effect of alcohol on the gut, the gut microbiome and liver function and structure, with a specific focus on micronutrients and areas for future research.

Diagnosis and Therapeutic Management of Liver Fibrosis by MicroRNA

Remarkable progress has been made in the treatment and control of hepatitis B and C viral infections. However, fundamental treatments for diseases in which liver fibrosis is a key factor, such as cirrhosis, alcoholic/nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis, are still under development and remain an unmet medical need. To solve this problem, it is essential to elucidate the pathogenesis of liver fibrosis in detail from a molecular and cellular perspective and to develop targeted therapeutic agents based on this information. Recently, microRNAs (miRNAs), functional RNAs of 22 nucleotides, have been shown to be involved in the pathogenesis of liver fibrosis. In addition, extracellular vesicles called “exosomes” have been attracting attention, and research is being conducted to establish noninvasive and extremely sensitive biomarkers using miRNAs in exosomes. In this review, we summarize miRNAs directly involved in liver fibrosis, miRNAs associated with diseases leading to liver fibrosis, and miRNAs related to complications of cirrhosis. We will also discuss the efficacy of each miRNA as a biomarker of liver fibrosis and pathology, and its potential application as a therapeutic agent.

Acceleration of Small Intestine Development and Remodeling of the Microbiome Following Hyaluronan 35 kDa Treatment in Neonatal Mice

The beneficial effects of human milk suppressing the development of intestinal pathologies such as necrotizing enterocolitis in preterm infants are widely known. Human milk (HM) is rich in a multitude of bioactive factors that play major roles in promoting postnatal maturation, differentiation, and the development of the microbiome. Previous studies showed that HM is rich in hyaluronan (HA) especially in colostrum and early milk. This study aims to determine the role of HA 35 KDa, a HM HA mimic, on intestinal proliferation, differentiation, and the development of the intestinal microbiome. We show that oral HA 35 KDa supplementation for 7 days in mouse pups leads to increased villus length and crypt depth, and increased goblet and Paneth cells, compared to controls. We also show that HA 35 KDa leads to an increased predominance of Clostridiales Ruminococcaceae, Lactobacillales Lactobacillaceae, and Clostridiales Lachnospiraceae. In seeking the mechanisms involved in the changes, bulk RNA seq was performed on samples from the terminal ileum and identified upregulation in several genes essential for cellular growth, proliferation, and survival. Taken together, this study shows that HA 35 KDa supplemented to mouse pups promotes intestinal epithelial cell proliferation, as well as the development of Paneth cells and goblet cell subsets. HA 35 KDa also impacted the intestinal microbiota; the implications of these responses need to be determined.

Alcohol-Related Liver Disease: Basic Mechanisms and Clinical Perspectives

Alcohol-related liver disease (ALD) refers to the liver damage occurring due to excessive alcohol consumption and involves a broad spectrum of diseases that includes liver steatosis, steatohepatitis, hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The progression of ALD is mainly associated with the amount and duration of alcohol usage; however, it is also influenced by genetic, epigenetic, and environmental factors. The definite diagnosis of ALD is based on a liver biopsy, although several non-invasive diagnostic tools and serum biomarkers have emerging roles in the early detection of ALD. While alcohol abstinence and nutritional support remain the cornerstone of ALD treatment, growing evidence has revealed that the therapeutic agents that target oxidative stress or gut-liver axis, inflammatory response inhibition, and liver regeneration enhancement also play a role in ALD management. Furthermore, microRNAs modulation and mesenchymal stem cell-based therapy have emerging potential as ALD therapeutic options. This review summarizes the updated understanding of the pathophysiology, diagnosis, and novel therapeutic approaches for ALD.

Immunological mechanisms and therapeutic targets of fatty liver diseases

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are the two major types of chronic liver disease worldwide. Inflammatory processes play key roles in the pathogeneses of fatty liver diseases, and continuous inflammation promotes the progression of alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH). Although both ALD and NAFLD are closely related to inflammation, their respective developmental mechanisms differ to some extent. Here, we review the roles of multiple immunological mechanisms and therapeutic targets related to the inflammation associated with fatty liver diseases and the differences in the progression of ASH and NASH. Multiple cell types in the liver, including macrophages, neutrophils, other immune cell types and hepatocytes, are involved in fatty liver disease inflammation. In addition, microRNAs (miRNAs), extracellular vesicles (EVs), and complement also contribute to the inflammatory process, as does intertissue crosstalk between the liver and the intestine, adipose tissue, and the nervous system. We point out that inflammation also plays important roles in promoting liver repair and controlling bacterial infections. Understanding the complex regulatory process of disrupted homeostasis during the development of fatty liver diseases may lead to the development of improved targeted therapeutic intervention strategies.

Contribution of glutaredoxin-1 to Fas s-glutathionylation and inflammation in ethanol-induced liver injury

AIMS

The reversible protein S-glutathionylation (PSSG) modification of Fas augments apoptosis, which can be reversed by the cytosolic deglutathionylation enzyme glutaredoxin-1 (Grx1), but its roles in alcoholic liver injury remain unknown. Therefore, the objective of this study was to investigate the impact of genetic ablation of Grx1 on Fas S-glutathionylation (Fas-SSG) in regulating ethanol-induced injury.

MATERIALS AND METHODS

We evaluated the Grx1 activity and oxidative damage, hepatic injury related indicators, Fas-SSG, we also assess the nuclear factor-κB (NF-κB) signaling, its downstream signal, and Akt signaling cascades, Furthermore, the number of Kupffer cells and related proinflammatory cytokines between WT and Grx1- groups after alcohol exposure.

KEY FINDINGS

Ethanol-fed mice had increased Grx1 activity and oxidative damage in the liver. Grx1-deficient mice had more serious liver damage when exposed to ethanol compared to that of wild-type mice, accompanied by increased alanine aminotransferase and aspartate aminotransferase levels, Fas-SSG, cleaved caspase-3 and hepatocyte apoptosis. Grx1 ablation resulted in the suppression of ethanol-induced NF-κB signaling, its downstream signal, and Akt signaling cascades, which are required for protection against Fas-mediated apoptosis. Accordingly, blocking NK-κB prevented Fas-induced apoptosis in WT mice but not Grx1-/- mice. Furthermore, the number of Kupffer cells and related proinflammatory cytokines, including Akt, were lower in Grx1-/- livers than those of the controls.

SIGNIFICANCE

Grx1 is essential for adaptation to alcohol exposure-induced oxidative injury by modulating Fas-SSG and Fas-induced apoptosis.

The Role of Hyaluronan Treatment in Intestinal Innate Host Defense

Hyaluronan (HA) is best known as an abundantly present extracellular matrix component found throughout the body of all vertebrates, including humans. Recent evidence, however, has demonstrated benefits of providing HA exogenously as a therapeutic modality for several medical conditions. Here we discuss the effects of providing HA treatment to increase innate host defense of the intestine, elucidate the size specific effects of HA, and discuss the role of various HA receptors as potential mediators of the HA effects in the intestine. This review especially focuses on HA interaction with the epithelium because it is the primary cellular barrier of the intestine and these cells play a critical balancing role between allowing water and nutrient absorption while excluding microbes and harmful dietary metabolites that are constantly in that organ's environment.

Macrophage Phenotype and Function in Liver Disorder

Hepatic macrophages are a remarkably heterogeneous population consisting of self-renewing tissue-resident phagocytes, termed Kupffer cells (KCs), and recruited macrophages derived from peritoneal cavity as well as the bone marrow. KCs are located in the liver sinusoid where they scavenge the microbe from the portal vein to maintain liver homeostasis. Liver injury may trigger hepatic recruitment of peritoneal macrophages and monocyte-derived macrophages. Studies describing macrophage accumulation have shown that hepatic macrophages are involved in the initiation and progression of various liver diseases. They act as tolerogenic antigen-presenting cells to inhibit T-cell activation by producing distinct sets of cytokines, chemokines, and mediators to maintain or resolve inflammation. Furthermore, by releasing regenerative growth factors, matrix metalloproteinase arginase, they promote tissue repair. Recent experiments found that KCs and recruited macrophages may play different roles in the development of liver disease. Given that hepatic macrophages are considerably plastic populations, their phenotypes and functions are likely switching along disease progression. In this review, we summarize current knowledge about the role of tissue-resident macrophages and recruited macrophages in pathogenesis of alcoholic liver disease (ALD), non-alcoholic steatohepatitis (NASH), viral hepatitis, and hepatocellular carcinoma (HCC).

Sirtuin 1 reduces hyaluronan synthase 2 expression by inhibiting nuclear translocation of NF-κB and expression of the long-noncoding RNA HAS2-AS1

Hyaluronan (HA) is one of the most prevalent glycosaminoglycans of the vascular extracellular matrix (ECM). Abnormal HA accumulation within blood vessel walls is associated with tissue inflammation and is prominent in most vascular pathological conditions such as atherosclerosis and restenosis. Hyaluronan synthase 2 (HAS2) is the main hyaluronan synthase enzyme involved in HA synthesis and uses cytosolic UDP-glucuronic acid and UDP-GlcNAc as substrates. The synthesis of UDP-glucuronic acid can alter the NAD⁺/NADH ratio via the enzyme UDP-glucose dehydrogenase, which oxidizes the alcohol group at C6 to the COO^- group. Here, we show that HAS2 expression can be modulated by sirtuin 1 (SIRT1), the master metabolic sensor of the cell, belonging to the class of NAD⁺-dependent deacetylases. Our results revealed the following. 1) Treatments of human aortic smooth muscle cells (AoSMCs) with SIRT1 activators (SRT1720 and resveratrol) inhibit both HAS2 expression and accumulation of pericellular HA coats. 2) Tumor necrosis factor α (TNFα) induced HA-mediated monocyte adhesion and AoSMC migration, whereas SIRT1 activation prevented immune cell recruitment and cell motility by reducing the expression levels of the receptor for HA-mediated motility, RHAMM, and the HA-binding protein TNF-stimulated gene 6 protein (TSG6). 3) SIRT1 activation prevented nuclear translocation of NF-κB (p65), which, in turn, reduced the levels of HAS2-AS1, a long-noncoding RNA that epigenetically controls HAS2 mRNA expression. In conclusion, we demonstrate that both HAS2 expression and HA accumulation by AoSMCs are down-regulated by the metabolic sensor SIRT1.

Oxidative stress mediates ethanol-induced skeletal muscle mitochondrial dysfunction and dysregulated protein synthesis and autophagy

Protein synthesis and autophagy are regulated by cellular ATP content. We tested the hypothesis that mitochondrial dysfunction, including generation of reactive oxygen species (ROS), contributes to impaired protein synthesis and increased proteolysis resulting in tissue atrophy in a comprehensive array of models. In myotubes treated with ethanol, using unbiased approaches, we identified defects in mitochondrial electron transport chain components, endogenous antioxidants, and enzymes regulating the tricarboxylic acid (TCA) cycle. Using high sensitivity respirometry, we observed impaired cellular respiration, decreased function of complexes I, II, and IV, and a reduction in oxidative phosphorylation in ethanol-treated myotubes and muscle from ethanol-fed mice. These perturbations resulted in lower skeletal muscle ATP content and redox ratio (NAD+/NADH). Ethanol also caused a leak of electrons, primarily from complex III, with generation of mitochondrial ROS and reverse electron transport. Oxidant stress with lipid peroxidation (thiobarbituric acid reactive substances) and protein oxidation (carbonylated proteins) were increased in myotubes and skeletal muscle from mice and humans with alcoholic liver disease. Ethanol also impaired succinate oxidation in the TCA cycle with decreased metabolic intermediates. MitoTEMPO, a mitochondrial specific antioxidant, reversed ethanol-induced mitochondrial perturbations (including reduced oxygen consumption, generation of ROS and oxidative stress), increased TCA cycle intermediates, and reversed impaired protein synthesis and the sarcopenic phenotype. We show that ethanol causes skeletal muscle mitochondrial dysfunction, decreased protein synthesis, and increased autophagy, and that these perturbations are reversed by targeting mitochondrial ROS.

Innate Immunity and Alcohol

The innate immunity has evolved during millions of years, and thus, equivalent or comparable components are found in most vertebrates, invertebrates, and even plants. It constitutes the first line of defense against molecules, which are either pathogen-derived or a danger signal themselves, and not seldom both. These molecular patterns are comprised of highly conserved structures, a common trait in innate immunity, and constitute very potent triggers for inflammation mediated via extracellular or intracellular pattern recognition receptors. Human culture is often interweaved with the consumption of alcohol, in both drinking habits, its acute or chronical misuse. Apart from behavioral effects as often observed in intoxicated individuals, alcohol consumption also leads to immunological modulation on the humoral and cellular levels. In the last 20 years, major advances in this field of research have been made in clinical studies, as well as in vitro and in vivo research. As every physician will experience intoxicated patients, it is important to be aware of the changes that this cohort undergoes. This review will provide a summary of the current knowledge on the influence of alcohol consumption on certain factors of innate immunity after a hit, followed by the current studies that display the effect of alcohol with a description of the model, the mode of alcohol administration, as well as its dose. This will provide a way for the reader to evaluate the findings presented.

The Crosstalk of miRNA and Oxidative Stress in the Liver: From Physiology to Pathology and Clinical Implications

The liver is the central metabolic organ of mammals. In humans, most diseases of the liver are primarily caused by an unhealthy lifestyle-high fat diet, drug and alcohol consumption- or due to infections and exposure to toxic substances like aflatoxin or other environmental factors. All these noxae cause changes in the metabolism of functional cells in the liver. In this literature review we focus on the changes at the miRNA level, the formation and impact of reactive oxygen species and the crosstalk between those factors. Both, miRNAs and oxidative stress are involved in the multifactorial development and progression of acute and chronic liver diseases, as well as in viral hepatitis and carcinogenesis, by influencing numerous signaling and metabolic pathways. Furthermore, expression patterns of miRNAs and antioxidants can be used for biomonitoring the course of disease and show potential to serve as possible therapeutic targets.

Crosstalk network among multiple inflammatory mediators in liver fibrosis

Liver fibrosis is the common pathological basis of all chronic liver diseases, and is the necessary stage for the progression of chronic liver disease to cirrhosis. As one of pathogenic factors, inflammation plays a predominant role in liver fibrosis via communication and interaction between inflammatory cells, cytokines, and the related signaling pathways. Damaged hepatocytes induce an increase in pro-inflammatory factors, thereby inducing the development of inflammation. In addition, it has been reported that inflammatory response related signaling pathway is the main signal transduction pathway for the development of liver fibrosis. The crosstalk regulatory network leads to hepatic stellate cell activation and proinflammatory cytokine production, which in turn initiate the fibrotic response. Compared with the past, the research on the pathogenesis of liver fibrosis has been greatly developed. However, the liver fibrosis mechanism is complex and many pathways involved need to be further studied. This review mainly focuses on the crosstalk regulatory network among inflammatory cells, cytokines, and the related signaling pathways in the pathogenesis of chronic inflammatory liver diseases. Moreover, we also summarize the recent studies on the mechanisms underlying liver fibrosis and clinical efforts on the targeted therapies against the fibrotic response.

Noncoding RNAs in alcoholic liver disease

Alcoholic liver disease (ALD) is a complex process with high morbitity and can cause liver dysfunction, which contains a wide spectrum of hepatic lesions, including steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. To date, the molecular mechanisms for ALD have not been fully explored and an effective therapy is still missing. Overwhelming evidence shows dysregulation of noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), is correlated with etiopathogenesis and progress of ALD including hepatocyte damage, disrupted lipid metabolism, aggressive inflammatory responses, oxidative stress, programmed cell death, fibrosis, and epigenetic changes induced by alcohol. For example, circulating miRNA-122 is a marker of hepatocyte damage, and miRNA-155 is a potential marker of inflammation, indicating their diagnosis therapeutic potential in ALD. In addition, roles for long noncoding RNAs (lncRNAs) and circular RNAs in ALD are being uncovered. Further, circulating ncRNAs and exosome-derived ncRNAs have attracted more attention lately, suggesting a role in the prevention and treatment of ALD. This review covers the roles of ncRNAs in ALD, and the potential uses as markers for diagnosis and therapeutic options.

Hyaluronan-Based Grafting Strategies for Liver Stem Cell Therapy and Tracking Methods

Cell adhesion is essential for survival, it plays important roles in physiological cell functions, and it is an innovative target in regenerative medicine. Among the molecular interactions and the pathways triggered during cell adhesion, the binding of cluster of differentiation 44 (CD44), a cell-surface glycoprotein involved in cell-cell interactions, to hyaluronic acid (HA), a major component of the extracellular matrix, is a crucial step. Cell therapy has emerged as a promising treatment for advanced liver diseases; however, so far, it has led to low cell engraftment and limited cell repopulation of the target tissue. Currently, different strategies are under investigation to improve cell grafting in the liver, including the use of organic and inorganic biomatrices that mimic the microenvironment of the extracellular matrix. Hyaluronans, major components of stem cell niches, are attractive candidates for coating stem cells since they improve viability, proliferation, and engraftment in damaged livers. In this review, we will discuss the new strategies that have been adopted to improve cell grafting and track cells after transplantation.

Hyaluronan synthase 2-mediated hyaluronan production mediates Notch1 activation and liver fibrosis

Hyaluronan (HA), a major extracellular matrix glycosaminoglycan, is a biomarker for cirrhosis. However, little is known about the regulatory and downstream mechanisms of HA overproduction in liver fibrosis. Hepatic HA and HA synthase 2 (HAS2) expression was elevated in both human and murine liver fibrosis. HA production and liver fibrosis were reduced in mice lacking HAS2 in hepatic stellate cells (HSCs), whereas mice overexpressing HAS2 had exacerbated liver fibrosis. HAS2 was transcriptionally up-regulated by transforming growth factor-β through Wilms tumor 1 to promote fibrogenic, proliferative, and invasive properties of HSCs via CD44, Toll-like receptor 4 (TLR4), and newly identified downstream effector Notch1. Inhibition of HA synthesis by 4-methylumbelliferone reduced HSC activation and liver fibrosis in mice. Our study provides evidence that HAS2 actively synthesizes HA in HSCs and that it promotes HSC activation and liver fibrosis through Notch1. Targeted HA inhibition may have potential to be an effective therapy for liver fibrosis.

miRNAs Involved in M1/M2 Hyperpolarization Are Clustered and Coordinately Expressed in Alcoholic Hepatitis

The innate immune system, including monocytes/macrophages, is critical to the progression of alcoholic liver disease (ALD). In response to chronic ethanol, Kupffer cells, the resident macrophage of livers, and peripheral monocytes become sensitized to bacterial lipopolysaccharides (LPS), express more pro-inflammatory cytokines and exhibit macrophage M1/M2 hyperpolarization. Since miRNAs play an important role in the regulation of M1/M2 polarization, we hypothesized that miRNAs regulating macrophage polarization would be dysregulated after chronic ethanol consumption. miRNA sequencing data from Kupffer cells isolated from rats fed an ethanol diet vs. control diet and qPCR data from PBMCs isolated from alcoholic hepatitis (AH) patients and healthy controls were used to assess the role of miRNAs in macrophage hyperpolarization in ALD. Differential expression analyses revealed 40 misregulated miRNAs in Kupffer cells from the chronic ethanol-fed rats compared to pair-fed controls. Nine of these miRNAs are known to be associated with macrophage polarization and consist of a mixture of M1- and M2-associated miRNAs, indicative of hyperpolarization. Twenty-three of the 40 differentially expressed miRNAs were localized to miRNA clusters throughout the genome. Correlation analyses revealed that miRNAs in three of these clusters were co-regulated and located within antisense non-coding RNAs. Similar to Kupffer cells from ethanol-fed rats, M1 and M2 polarization markers, as well as sensitivity to LPS, were elevated in PBMCs from AH patients compared to healthy controls. These increases were associated with an up-regulation of polarization-associated miRNAs, including miR-125a-5p, a miRNA associated with hyperpolarization. miR-125a-5p is clustered in the genome with other miRNAs inside a host gene, Spaca6, which was also upregulated in PBMCs, as well as isolated monocytes, from AH patients. Finally, correlation analyses revealed co-regulation of human polarization-associated miRNA clusters. While expression of polarization-associated miRNAs in clusters was upregulated in AH compared to healthy controls, co-regulation of the miRNAs within a cluster was independent of disease state. Together, these results reveal that global changes in miRNA regulation are associated with polarization phenotypes in Kupffer cells from rat after chronic ethanol as well as in PBMCs from patients with AH. Importantly, polarization-associated miRNAs were localized to coordinately regulated clusters.

Safety of Hyaluronan 35 in Healthy Human Subjects: A Pilot Study

Background. Hyaluronan (HA) is a naturally occurring glycosaminoglycan polymer produced in all vertebrates, and usually present at the high molecular weight (>10⁶ Da). Low molecular weight HA has signaling properties, and fragments ~35 kDa size (HA35) have biological activity in eliciting epithelial β-defensins and tight junction proteins, notably ZO1, important components of innate host defense arsenal of the gut barrier in preclinical models. Safety, tolerability, impact on metabolism, gut permeability, and microbiome composition in healthy human subjects were all evaluated prospectively. Methods. Pharmaceutical grade HA35 (140 mg in water once daily for seven days), was administered orally to 20 healthy subjects (30.7 ± 5.6 years). Demographical, clinical, biochemical laboratory tests, metabolic function and stool microbiome composition were measured on Day 0, 8 and 28. Results. HA35 was tolerated well in all subjects with no serious adverse events in any subjects. No statistical differences in any of the measurements were seen among the study group over the course of the trial. In aggregate there were no changes in demographical, clinical, biochemical laboratory tests, and metabolic function or microbiome composition during the 28-day study. Conclusion. Oral HA35 administration (140 mg/day) is a safe treatment in healthy individuals and does not affect metabolic, inflammatory or microbiome parameters.

Inflammatory pathways in alcoholic steatohepatitis

Inflammatory processes are primary contributors to the development and progression of alcoholic steatohepatitis (ASH), with severe alcoholic hepatitis characterised by non-resolving inflammation. Inflammation in the progression of ASH is a complex response to microbial dysbiosis, loss of barrier integrity in the intestine, hepatocellular stress and death, as well as inter-organ crosstalk. Herein, we review the roles of multiple cell types that are involved in inflammation in ASH, including resident macrophages and infiltrating monocytes, as well as other cell types in the innate and adaptive immune system. In response to chronic, heavy alcohol exposure, hepatocytes themselves also contribute to the inflammatory process; hepatocytes express a large number of chemokines and inflammatory mediators and can also release damage-associated molecular patterns during injury and death. These cellular responses are mediated and accompanied by changes in the expression of pro- and anti-inflammatory cytokines and chemokines, as well as by signals which orchestrate the recruitment of immune cells and activation of the inflammatory process. Additional mechanisms for cell-cell and inter-organ communication in ASH are also reviewed, including the roles of extracellular vesicles and microRNAs, as well as inter-organ crosstalk. We highlight the concept that inflammation also plays an important role in promoting liver repair and controlling bacterial infection. Understanding the complex regulatory processes that are disrupted during the progression of ASH will likely lead to better targeted strategies for therapeutic interventions.

Genetic and Epigenetic Modifiers of Alcoholic Liver Disease

Alcoholic liver disease (ALD), a disorder caused by excessive alcohol consumption is a global health issue. More than two billion people consume alcohol in the world and about 75 million are classified as having alcohol disorders. ALD embraces a wide spectrum of hepatic lesions including steatosis, alcoholic steatohepatitis (ASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). ALD is a complex disease where environmental, genetic, and epigenetic factors contribute to its pathogenesis and progression. The severity of alcohol-induced liver disease depends on the amount, method of usage and duration of alcohol consumption as well as on age, gender, presence of obesity, and genetic susceptibility. Genome-wide association studies and candidate gene studies have identified genetic modifiers of ALD that can be exploited as non-invasive biomarkers, but which do not completely explain the phenotypic variability. Indeed, ALD development and progression is also modulated by epigenetic factors. The premise of this review is to discuss the role of genetic variants and epigenetic modifications, with particular attention being paid to microRNAs, as pathogenic markers, risk predictors, and therapeutic targets in ALD.

Role of microRNAs in alcohol-induced liver disorders and non-alcoholic fatty liver disease

MicroRNAs (miRNAs) are small non-coding RNAs that regulate multiple physiological and pathological functions through the modulation of gene expression at the post-transcriptional level. Accumulating evidence has established a role for miRNAs in the development and pathogenesis of liver disease. Specifically, a large number of studies have assessed the role of miRNAs in alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD), two diseases that share common underlying mechanisms and pathological characteristics. The purpose of the current review is to summarize and update the body of literature investigating the role of miRNAs in liver disease. In addition, the potential use of miRNAs as biomarkers and/or therapeutic targets is discussed. Among all miRNAs analyzed, miR-34a, miR-122 and miR-155 are most involved in the pathogenesis of NAFLD. Of note, these three miRNAs have also been implicated in ALD, reinforcing a common disease mechanism between these two entities and the pleiotropic effects of specific miRNAs. Currently, no single miRNA or panel of miRNAs has been identified for the detection of, or staging of ALD or NAFLD. While promising results have been shown in murine models, no therapeutic based-miRNA agents have been developed for use in humans with liver disease.

MicroRNAs in alcoholic liver disease: Recent advances and future applications

Alcoholic liver disease (ALD) is characterized by hepatocyte damage, inflammatory cell activation, and increased intestinal permeability leading to the clinical manifestations of alcoholic hepatitis. Selected members of the family of microRNAs (miRNAs) are affected by alcohol, resulting in an abnormal miRNA profile in the liver and circulation in ALD. Increasing evidence suggests that miRNAs that regulate inflammation, lipid metabolism and promote cancer are affected by excessive alcohol administration in mouse models of ALD. This communication highlights recent findings in miRNA expression and functions as they relate to the pathogenesis of ALD. The cell-specific distribution of miRNAs, as well as the significance of circulating extracellular miRNAs, is discussed as potential biomarkers. Finally, the prospects of miRNA-based therapies are evaluated in ALD.

Immune Regulation of Tissue Repair and Regeneration via miRNAs-New Therapeutic Target

The importance of immunity in tissue repair and regeneration is now evident. Thus, promoting tissue healing through immune modulation is a growing and promising field. Targeting microRNAs (miRNAs) is an appealing option since they regulate immunity through post-transcriptional gene fine-tuning in immune cells. Indeed, miRNAs are involved in inflammation as well as in its resolution by controlling immune cell phenotypes and functions. In this review, we first discuss the immunoregulatory role of miRNAs during the restoration of tissue homeostasis after injury, focusing mainly on neutrophils, macrophages and T lymphocytes. As tissue examples, we present the immunoregulatory function of miRNAs during the repair and regeneration of the heart, skeletal muscles, skin and liver. Secondly, we discuss recent technological advances for designing therapeutic strategies which target miRNAs. Specifically, we highlight the possible use of miRNAs and anti-miRNAs for promoting tissue regeneration via modulation of the immune system.

Complement Factor D protects mice from ethanol-induced inflammation and liver injury

Complement plays a crucial role in microbial defense and clearance of apoptotic cells. Emerging evidence suggests complement is an important contributor to alcoholic liver disease. While complement component 1, Q subcomponent (C1q)-dependent complement activation contributes to ethanol-induced liver injury, the role of the alternative pathway in ethanol-induced injury is unknown. Activation of complement via the classical and alternative pathways was detected in alcoholic hepatitis patients. Female C57BL/6J [wild type (WT)], C1q-deficient ( C1qa-/-, lacking classical pathway activation), complement protein 4-deficient ( C4-/-, lacking classical and lectin pathway activation), complement factor D-deficient ( FD-/-, lacking alternative pathway activation), and C1qa/FD-/- (lacking classical and alternative pathway activation) mice were fed an ethanol-containing liquid diet or pair-fed control diet for 4 or 25 days. Following chronic ethanol exposure, liver injury, steatosis, and proinflammatory cytokine expression were increased in WT but not C1qa-/-, C4-/-, or C1qa/FD-/- mice. In contrast, liver injury, steatosis, and proinflammatory mediators were robustly increased in ethanol-fed FD-/- mice compared with WT mice. Complement activation, assessed by hepatic accumulation of C1q and complement protein 3 (C3) cleavage products (C3b/iC3b/C3c), was evident in livers of WT mice in response to both short-term and chronic ethanol. While C1q accumulated in ethanol-fed FD-/- mice (short term and chronic), C3 cleavage products were detected after short-term but not chronic ethanol. Consistent with impaired complement activation, chronic ethanol induced the accumulation of apoptotic cells and fibrogenic responses in the liver of FD-/- mice. These data highlight the protective role of complement factor D (FD) and suggest that FD-dependent amplification of complement is an adaptive response that promotes hepatic healing and recovery in response to chronic ethanol. NEW & NOTEWORTHY Complement, a component of the innate immune system, is an important pathophysiological contributor to ethanol-induced liver injury. We have identified a novel role for factor D, a component of the alternative pathway, in protecting the liver from ethanol-induced inflammation, accumulation of apoptotic hepatocytes, and profibrotic responses. These data indicate a dual role of complement with regard to inflammatory and protective responses and suggest that accumulation of apoptotic cells impairs hepatic healing/recovery during alcoholic liver disease.

MiR-181b inhibits P38/JNK signaling pathway to attenuate autophagy and apoptosis in juvenile rats with kainic acid-induced epilepsy via targeting TLR4

OBJECTIVE

To explore the role of miR-181b in alterations of apoptosis and autophagy in the kainic acid (KA)-induced epileptic juvenile rats via modulating TLR4 and P38/JNK signaling pathway.

METHODS

Dual-luciferase reporter assay was performed to testify the targeting relationship between miR-181b and TLR4. After intracerebroventricular injection (i.c.v.) of KA, rats were injected with miR-181b agomir and TLR4 inhibitor (TAK-242). The TLR-4 activator lipopolysaccharide (LPS) was also administered into rats immediately after injection with miR-181b agomir. Quantitative real-time-polymerase chain reaction (qRT-PCR) was used for detections of miR-181b and TLR4 expressions, hematoxylin-eosin (HE) and Nissl staining for observation of the hippocampus morphological changes, and TUNEL staining for apoptosis analysis. Moreover, western blot was determined to detect TLR4 and P38/JNK pathway proteins, as well as autophagy- and apoptosis-related proteins.

RESULTS

TLR4 was identified as a direct target of miR-181b using Dual-luciferase reporter assay. KA rats injected with miR-181b agomir or TAK-242 had improved learning and memory abilities, reduced seizure severity of Racine's scale, and lessened neuron injury. Additionally, miR-181b agomir or TAK-242 could significantly inhibit P38/JNK signaling, decrease LC3II/I, Beclin-1, ATG5, ATG7, ATG12, Bax, and cleaved caspases-3, but increase p62 and Bcl-2 expression. No significances were found between KA group and KA + miR-181b + LPS group.

CONCLUSION

MiR-181b could inhibit P38/JNK signaling pathway via targeting TLR4, thereby exerting protective roles in attenuating autophagy and apoptosis of KA-induced epileptic juvenile rats.

Regulation of hyaluronan biosynthesis and clinical impact of excessive hyaluronan production

The tightly regulated biosynthesis and catabolism of the glycosaminoglycan hyaluronan, as well as its role in organizing tissues and cell signaling, is crucial for the homeostasis of tissues. Overexpression of hyaluronan plays pivotal roles in inflammation and cancer, and markedly high serum and tissue levels of hyaluronan are noted under such pathological conditions. This review focuses on the complexity of the regulation at transcriptional and posttranslational level of hyaluronan synthetic enzymes, and the outcome of their aberrant expression and accumulation of hyaluronan in clinical conditions, such as systemic B-cell cancers, aggressive breast carcinomas, metabolic diseases and virus infection.

Cytochrome P450s and Alcoholic Liver Disease

Alcohol consumption causes liver diseases, designated as Alcoholic Liver Disease (ALD). Because alcohol is detoxified by alcohol dehydrogenase (ADH), a major ethanol metabolism system, the development of ALD was initially believed to be due to malnutrition caused by alcohol metabolism in liver. The discovery of the microsomal ethanol oxidizing system (MEOS) changed this dogma. Cytochrome P450 enzymes (CYP) constitute the major components of MEOS. Cytochrome P450 2E1 (CYP2E1) in MEOS is one of the major ROS generators in liver and is considered to be contributive to ALD. Our labs have been studying the relationship between CYP2E1 and ALD for many years. Recently, we found that human CYP2A6 and its mouse analog CYP2A5 are also induced by alcohol. In mice, the alcohol induction of CYP2A5 is CYP2E1-dependent. Unlike CYP2E1, CYP2A5 protects against the development of ALD. The relationship of CYP2E1, CYP2A5, and ALD is a major focus of this review.