Chronic ethanol feeding alters miRNA expression dynamics during liver regeneration

Influence of polymorphisms in TNF-α and IL1β on susceptibility to alcohol induced liver diseases and therapeutic potential of miR-124-3p impeding TNF-α/IL1β mediated multi-cellular signaling in liver microenvironment

Background and aims

Alcoholic liver disease (ALD) is the leading cause of the liver cirrhosis related death worldwide. Excessive alcohol consumption resulting enhanced gut permeability which trigger sensitization of inflammatory cells to bacterial endotoxins and induces secretion of cytokines, chemokines leading to activation of stellate cells, neutrophil infiltration and hepatocyte injury followed by steatohepatitis, fibrosis and cirrhosis. But all chronic alcoholics are not susceptible to ALD. This study investigated the causes of differential immune responses among ALD patients and alcoholic controls (ALC) to identify genetic risk factors and assessed the therapeutic potential of a microRNA, miR-124-3p.

Materials and methods

Bio-Plex Pro™ Human Chemokine analysis/qRT-PCR array was used for identification of deregulated immune genes. Sequencing/luciferase assay/ELISA detected and confirmed the polymorphisms. THP1 co-cultured with HepG2/LX2/HUVEC and apoptosis assay/qRT-PCR/neutrophil migration assay were employed as required.

Results

The combined data analysis of the GSE143318/Bio-Plex Pro™ Human Chemokine array and qRT-PCR array revealed that six genes (TNFα/IL1β/IL8/MCP1/IL6/TGFβ) were commonly overexpressed in both serum/liver tissue of ALD-patients compared to ALC. The promoter sequence analysis of these 6 genes among ALD (n=322)/ALC (n=168) samples revealed that only two SNPs, rs361525(G/A) at -238 in TNF-α/rs1143627(C/T) at -31 in IL1β were independently associated with ALD respectively. To evaluate the functional implication of these SNPs on ALD development, the serum level of TNF-α/IL1β was verified and observed significantly higher in ALD patients with risk genotypes TNF-α-238GA/IL1β-31CT+TT than TNF-α-238GG/IL1β-31CC. The TNF-α/IL1β promoter Luciferase-reporter assays showed significantly elevated level of luciferase activities with risk genotypes -238AA/-31TT than -238GG/-31CC respectively. Furthermore, treatment of conditioned medium of TNF-α/IL1β over-expressed THP1 cells to HepG2/LX2/HUVEC cells independently showed enhanced level of ER stress and apoptosis in HepG2/increased TGFβ and collagen-I production by LX2/huge neutrophil infiltration through endothelial layer. However, restoration of miR-124-3p in THP1 attenuated such inter-cellular communications and hepatocyte damage/collagen production/neutrophil infiltration were prohibited. Target analysis/luciferase-reporter assays revealed that both TNF-α/IL1β were inhibited by miR-124-3p along with multiple genes from TLR4 signaling/apoptosis/fibrogenesis pathways including MYD88, TRAF3/TRADD, Caspase8/PDGFRA, TGFβR2/MCP1, and ICAM1 respectively.

Conclusion

Thus, rs361525(G/A) in TNF-α and rs1143627(C/T) in IL1β gene may be used as early predictors of ALD susceptibility among East Indian population. Impeding overexpressed TNF-α/IL1β and various genes from associated immune response pathways, miR-124-3p exhibits robust therapeutic potential for ALD patients.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Epigenetics and the role of nutraceuticals in health and disease

In the post-genomic era, the data provided by complete genome sequencing could not answer several fundamental questions about the causes of many noninfectious diseases, diagnostic biomarkers, and novel therapeutic approaches. The rapidly expanding understanding of epigenetic mechanisms, as well as widespread acceptance of their hypothesized role in disease induction, facilitated the development of a number of novel diagnostic markers and therapeutic concepts. Epigenetic aberrations are reversible in nature, which enables the treatment of serious incurable diseases. Therefore, the interest in epigenetic modulatory effects has increased over the last decade, so about 60,000 publications discussing the expression of epigenetics could be detected in the PubMed database. Out of these, 58,442 were published alone in the last 10 years, including 17,672 reviews (69 historical articles), 314 clinical trials, 202 case reports, 197 meta-analyses, 156 letters to the editor, 108 randomized controlled trials, 87 observation studies, 40 book chapters, 22 published lectures, and 2 clinical trial protocols. The remaining publications are either miscellaneous or a mixture of the previously mentioned items. According to the species and gender, the publications included 44,589 human studies (17,106 females, 14,509 males, and the gender is not mentioned in the remaining papers) and 30,253 animal studies. In the present work, the role of epigenetic modulations in health and disease and the influencing factors in epigenetics are discussed.

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.

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.

Non-Invasive microRNA Profiling in Saliva can Serve as a Biomarker of Alcohol Exposure and Its Effects in Humans

Alcohol Use Disorder (AUD) is one of the most prevalent mental disorders worldwide. Considering the widespread occurrence of AUD, a reliable, cheap, non-invasive biomarker of alcohol consumption is desired by healthcare providers, clinicians, researchers, public health and criminal justice officials. microRNAs could serve as such biomarkers. They are easily detectable in saliva, which can be sampled from individuals in a non-invasive manner. Moreover, microRNAs expression is dynamically regulated by environmental factors, including alcohol. Since excessive alcohol consumption is a hallmark of alcohol abuse, we have profiled microRNA expression in the saliva of chronic, heavy alcohol abusers using microRNA microarrays. We observed significant changes in salivary microRNA expression caused by excessive alcohol consumption. These changes fell into three categories: downregulated microRNAs, upregulated microRNAs, and microRNAs upregulated de novo. Analysis of these combinatorial changes in microRNA expression suggests dysregulation of specific biological pathways leading to impairment of the immune system and development of several types of epithelial cancer. Moreover, some of the altered microRNAs are also modulators of inflammation, suggesting their contribution to pro-inflammatory mechanisms of alcohol actions. Establishment of the cellular source of microRNAs in saliva corroborated these results. We determined that most of the microRNAs in saliva come from two types of cells: leukocytes involved in immune responses and inflammation, and buccal cells, involved in development of epithelial, oral cancers. In summary, we propose that microRNA profiling in saliva can be a useful, non-invasive biomarker allowing the monitoring of alcohol abuse, as well as alcohol-related inflammation and early detection of cancer.

Dysregulation of miR-21-associated miRNA regulatory networks by chronic ethanol consumption impairs liver regeneration

Impaired liver regeneration has been considered as a hallmark of progression of alcohol-associated liver disease. Our previous studies demonstrated that in vivo inhibition of the microRNA (miRNA) miR21 can restore regenerative capacity of the liver in chronic ethanol-fed animals. The present study focuses on the role of microRNA regulatory networks that are likely to mediate the miR-21 action. Rats were chronically fed an ethanol-enriched diet along with pair-fed control animals and treated with AM21 (anti-miR-21), a locked nucleic acid antisense to miR-21. Partial hepatectomy (PHx) was performed and miRNA expression profiling over the course of liver regeneration was assessed. Our results showed dynamic expression changes in several miRNAs after PHx, notably with altered miRNA expression profiles between ethanol and control groups. We found that in vivo inhibition of miR-21 led to correlated differential expression of miR-340-5p and anticorrelated expression of miR-365, let-7a, miR-1224, and miR-146a across all sample groups after PHx. Gene set enrichment analysis identified a miRNA signature significantly associated with hepatic stellate cell activation within whole liver tissue data. We hypothesized that at least part of the PHx-induced miRNA network changes responsive to miR-21 inhibition is localized to hepatic stellate cells. We validated this hypothesis using AM21 and TGF-β treatments in LX-2 human hepatic stellate cells in culture and measured expression levels of select miRNAs by quantitative RT-PCR. Based on the in vivo and in vitro results, we propose a hepatic stellate cell miRNA regulatory network as contributing to the restoration of liver regenerative capacity by miR-21 inhibition.

Emerging Therapies for Alcoholic Hepatitis

The incidence of alcoholic hepatitis is increasing while the mortality rate remains high. The single current available therapy for severe alcoholic hepatitis is administration of corticosteroids for patients with severe alcoholic hepatitis, which has demonstrated limited benefits, providing a short-term mortality benefit with a marginal response rate. There is a need for developing safe and effective therapies. This article reviews novel therapies targeting various mechanisms in the pathogenesis of alcoholic hepatitis, such as the gut-liver axis, inflammatory cascade, oxidative stress, and hepatic regeneration. Current ongoing clinical trials for alcoholic hepatitis also are described.

Oxidative Stress-A Key Player in the Course of Alcohol-Related Liver Disease

Oxidative stress is known to be an inseparable factor involved in the presentation of liver disorders. Free radicals interfere with DNA, proteins, and lipids, which are crucial in liver metabolism, changing their expression and biological functions. Additionally, oxidative stress modifies the function of micro-RNAs, impairing the metabolism of hepatocytes. Free radicals have also been proven to influence the function of certain transcriptional factors and to alter the cell cycle. The pathological appearance of alcohol-related liver disease (ALD) constitutes an ideal example of harmful effects due to the redox state. Finally, ethanol-induced toxicity and overproduction of free radicals provoke irreversible changes within liver parenchyma. Understanding the underlying mechanisms associated with the redox state in the course of ALD creates new possibilities of treatment for patients. The future of hepatology may become directly dependent on the effective action against reactive oxygen species. This review summarizes current data on the redox state in the natural history of ALD, highlighting the newest reports on this topic.

Alcoholic and Non-Alcoholic Liver Diseases: Promising Molecular Drug Targets and their Clinical Development

Alcoholic and non-alcoholic fatty liver diseases have become a serious concern worldwide. Both these liver diseases have an identical pathology, starting from simple steatosis to cirrhosis and, ultimately to hepatocellular carcinoma. Treatment options for alcoholic liver disease (ALD) are still the same as they were 50 years ago which include corticosteroids, pentoxifylline, antioxidants, nutritional support and abstinence; and for non-alcoholic fatty liver disease (NAFLD), weight loss, insulin sensitizers, lipid-lowering agents and anti-oxidants are the only treatment options. Despite broad research in understanding the disease pathophysiology, limited treatments are available for clinical use. Some therapeutic strategies based on targeting a specific molecule have been developed to lessen the consequences of disease and are under clinical investigation. Therefore, focus on multiple molecular targets will help develop an efficient therapeutic strategy. This review comprises a brief overview of the pathogenesis of ALD and NAFLD; recent molecular drug targets explored for ALD and NAFLD that may prove to be effective for multiple therapeutic regimens and also the clinical status of these promising drug targets for liver diseases.

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.

Chronic exposure to ethanol alters the expression of miR-155, miR-122 and miR-217 in alcoholic liver disease in an adult zebrafish model

AIM

The aim of this study was to evaluate the hepatic and circulating expression of miR-155, miR-122 and miR-217 in a model of chronic exposure to ethanol in adult zebrafish.

METHODS

Wild-type adult zebrafish were divided into two groups (n = 281): an EG (exposed to 0.5% v/v Ethanol in aquarium water) and a CG (without ethanol). After 28 days the animals were euthanized, followed by histopathological analysis, quantification of lipids, triglycerides and inflammatory cytokines in liver tissue. miR-155, miR-122 and miR-217 gene expression was quantified in liver tissue and serum.

RESULTS

We observed hepatic lesions and increased accumulation of hepatic lipids in the EG. The expression of il-1β was higher in the EG, but there were no differences in il-10 and tnf-α between groups. In the liver, expression of miR-122 and miR-155 was higher in the EG. The circulating expression of miR-155 and miR-217 was significantly higher in the EG.

CONCLUSION

Chronic exposure to ethanol in zebrafish leads to altered hepatic and circulating expression of miR-155, miR-122 and miR-217. This confirms its potential as a biomarker and therapeutic target.

Insights into the Role of Granulocyte Colony-Stimulating Factor in Severe Alcoholic Hepatitis

Alcohol use disorder is the predominant cause of chronic liver disease globally. The standard of care for the treatment of alcoholic hepatitis, corticosteroids, has been shown to provide a therapeutic response in ∼60% of carefully selected patients with a short-term survival benefit. The patients who do not respond to steroids, or are ineligible due to infections or very severe disease, have little options other than liver transplantation. There is, thus, a large unmet need for new therapeutic strategies for this large and sick group of patients. Granulocyte colony stimulating factor (G-CSF) has been shown to favorably modulate the intrahepatic immune milieu and stimulate the regenerative potential of the liver. Initial studies have shown encouraging results with G-CSF in patients with severe alcoholic hepatitis. It has also been found to help steroid nonresponsive patients. There is, however, a need for careful selection of patients, regular dose monitoring and close observation for adverse events of G-CSF. In this review, we analyze the basis of the potential benefits, clinical studies, cautions and challenges in the use of G-CSF in alcoholic hepatitis.

The Impact of Acute or Chronic Alcohol Intake on the NF-κB Signaling Pathway in Alcohol-Related Liver Disease

Ethanol misuse is frequently associated with a multitude of profound medical conditions, contributing to health-, individual- and social-related damage. A particularly dangerous threat from this classification is coined as alcoholic liver disease (ALD), a liver condition caused by prolonged alcohol overconsumption, involving several pathological stages induced by alcohol metabolic byproducts and sustained cellular intoxication. Molecular, pathological mechanisms of ALD principally root in the innate immunity system and are especially associated with enhanced functionality of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. NF-κB is an interesting and convoluted DNA transcription regulator, promoting both anti-inflammatory and pro-inflammatory gene expression. Thus, the abundancy of studies in recent years underlines the importance of NF-κB in inflammatory responses and the mechanistic stimulation of inner molecular motifs within the factor components. Hereby, in the following review, we would like to put emphasis on the correlation between the NF-κB inflammation signaling pathway and ALD progression. We will provide the reader with the current knowledge regarding the chronic and acute alcohol consumption patterns, the molecular mechanisms of ALD development, the involvement of the NF-κB pathway and its enzymatic regulators. Therefore, we review various experimental in vitro and in vivo studies regarding the research on ALD, including the recent active compound treatments and the genetic modification approach. Furthermore, our investigation covers a few human studies.

The Hepatic Sinusoid in Aging and Disease: Update and Advances From the 20th Liver Sinusoid Meeting

This is a meeting report of the 2019 Liver Sinusoid Meeting, 20th International Symposium on Cells of the Hepatic Sinusoid, held in Sydney, Australia, in September 2019. The meeting, which was organized by the International Society for Hepatic Sinusoidal Research, provided an update on the recent advances in the field of hepatic sinusoid cells in relation to cell biology, aging, and liver disease, with particular focus on the molecular and cellular targets involved in hepatic fibrosis, nonalcoholic hepatic steatohepatitis, alcoholic liver disease, hepatocellular carcinoma, and cirrhosis. In addition, the meeting highlighted the recent advances in regenerative medicine, targeted nanotechnologies, therapeutics, and novel methodologies.

The effects of epigenetic modification on the occurrence and progression of liver diseases and the involved mechanism

Introduction: Epigenetic modification is a type of gene expression and regulation that does not involve changes in DNA sequences. An increasing number of studies have proven that epigenetic modifications play an important role in the occurrence and progression of liver diseases through the gene regulation and protein expressions of hepatocellular lipid metabolism, inflammatory reaction, cell proliferation, and activation, etc.Areas covered: In this study, we elaborated and analyzed the underlying functional mechanism of epigenetic modification in alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), liver fibrosis (LF), viral hepatitis, hepatocellular carcinoma (HCC), and research progress of recent years.Expert opinion: The further understanding of epigenetic mechanisms that can regulate gene expression and cell phenotype leads to new insights in epigenetic control of chronic liver disease. Currently, hepatologists are exploring the role of DNA methylation, histone/chromatin modification, and non-coding RNA in specific liver pathology. These findings have led to advances in direct epigenetic biomarker testing of patient tissue or body fluid specimens, as well as quantitative analysis. Based on these findings, drug validation of some targets involved in the epigenetic mechanism of liver disease is gradually being carried out clinically.

Protocatechuic Acid-Mediated miR-219a-5p Activation Inhibits the p66shc Oxidant Pathway to Alleviate Alcoholic Liver Injury

Alcohol abuse has become common worldwide and has been recognized as a major cause of chronic alcoholic liver disease (ALD). ALD encompasses a complex process that includes a broad scope of hepatic lesions, ranging from steatosis to cirrhosis. In particular, reactive oxygen species (ROS) are mainly involved. Numerous studies have shown that p66shc plays a significant role in ALD. Protocatechuic acid (PCA), a dihydroxybenzoic acid that is naturally found in green tea, vegetables, and fruits, has efficient free radical scavenging effects. In this study, we aimed to assess the protective effect of PCA on ALD and to evaluate the microRNA- (miRNA-) p66shc-mediated reduction of ROS formation in ALD. Our results demonstrated that PCA treatment significantly decreased p66shc expression and downstream ROS formation in ALD. miR-219a-5p, which was identified by bioinformatics and experimental analysis, was enhanced by PCA and subsequently suppressed p66shc expression. Importantly, p66shc played an essential role in the protection of PCA-stimulated miR-219a-5p overexpression. Overall, these findings show that PCA-stimulated miR-219a-5p expression mitigates ALD by reducing p66shc-mediated ROS formation. This study may contribute to the development of therapeutic interventions for ALD.

Natural compounds in the chemoprevention of alcoholic liver disease

Alcoholic liver disease (ALD), caused by excessive consumption of alcohol, is a major cause of chronic liver disease worldwide. Much effort has been expended to explore the pathogenesis of ALD. Hepatic cell injury, oxidative stress, inflammation, regeneration, and bacterial translocation are all involved in the pathogenesis of ALD. Immediate abstinence is the most important therapeutic treatment for affected individuals. However, the medical treatment for ALD had not advanced in a long period. Intriguingly, an increasing body of research indicates the potential of natural compounds in the targeted therapy of ALD. A plethora of dietary natural products such as flavonoids, resveratrol, saponins, and β-carotene are found to exert protective effects on ALD. This occurs through various mechanisms composed of antioxidative, anti-inflammatory, iron chelation, pro-apoptosis, and/or antiproliferation of hepatic stellate cells and hepatocellular carcinoma cells. In this review, we will summarize current knowledge about the pathogenesis and treatments of ALD and focus on the potential of natural compounds in ALD therapies and underlying mechanisms.

Circulating Extracellular Vesicles and Their miR "Barcode" Differentiate Alcohol Drinkers With Liver Injury and Those Without Liver Injury in Severe Trauma Patients

Short Summary: Extracellular vesicles (EVs), released during tissue/cell injury, contain a “barcode” indicating specific microRNAs (miRs) that can uncover their origin. We examined whether systemic EVs possessing hepatic miR-signatures would indicate ongoing liver injury and clinical complications in trauma patients (TP). We grouped the patients of alcoholic drinkers into “alcohol-drinkers with liver injury (LI)” (EtOH with LI) or “alcohol-drinkers without LI” (EtOH w/o LI) and we compared these groups to “non-drinkers” (no EtOH). When we examined patient blood from the EtOH with LI group we found the total number of EVs to be increased, along with an increase in miR-122 and let7f—two EV-associated miRNAs—and several inflammation-associating cytokines, such as interleukin (IL)-6 and IL-33. In contrast, all of the aforementioned readouts were found to be decreased in the EtOH w/o LI group. These novel data demonstrate that hepatocyte damage in alcohol-intoxicated trauma patients presenting with liver injury can be reflected by an increase in circulating serum EVs, their specific miR-“barcode” and the concomitant increase of systemic inflammatory markers IL-6 and IL-33. Anti-inflammatory effect of alcohol-drinking in EtOH w/o LI can be presented by a reduced number of hepato-derived EVs, no upregulation of IL-6 and IL-33, and a miR “barcode” different from patients presenting with liver injury.

Background: Alcohol abuse is associated with (neuro)protective effects related to (head) injuries, and with negative effects regarding infection rates and survival in severely injured trauma patients (TP). Extracellular vesicles (EVs), which are released during tissue and/or cell injury, can contain a “barcode” including specific microRNAs (miRs) that uncover their origin. We examined whether EVs with a hepatic miR signature can be systemically measured, and whether they can indicate ongoing liver injury in alcohol-intoxicated TP and foretell clinical complications.

Patients/Methods: We enrolled 35 TP and measured blood EVs, IL-6, TNF-alpha, IL-1beta, IL-10 and IL-33, alcohol (ethanol, EtOH) concentration (BAC), GLDH, GGT, AST, ALT, leukocytes, platelets, and bilirubin. Within circulating EVs we measured the expression levels of miR-122, let7f, miR21, miR29a, miR-155, and miR-146a. Patients of alcohol-drinkers were grouped into “alcohol drinkers with liver injury (LI)” (EtOH with LI) or “alcohol drinkers without LI” (EtOH w/o LI) and compared to “non-drinkers” (no EtOH). We assessed systemic injury characteristics and the outcome of hospitalization with regard to sepsis, septic shock, pneumonia, or mortality.

Results: EtOH with LI patients had significantly increased rates of pneumonia vs. the EtOH w/o LI group. EVs, IL-6, and IL-33 levels were significantly increased in EtOH with LI vs. EtOH w/o LI group (p < 0.05). EV number correlated positively with ALT and IL-6 (p < 0.0001). Two miRs, miR-122 and let7f, were increased only in the blood EVs from the EtOH with LI group (p < 0.05). Five miRs, miR-122, let7f, miR-21, miR-29a, and miR-146a, were reduced in the blood EVs from the EtOH w/o LI group, vs. no EtOH (p < 0.05). Notably miR-122 correlated significantly with increased bilirubin levels in the EtOH with LI group (p < 0.05).

Conclusions: Liver injury in alcohol-intoxicated TP is reflected by increased EV numbers, their specific miR barcode, and the correlated increase of systemic inflammatory markers IL-6 and IL-33. Interestingly, severely injured TP without liver injury were found to have a reduced number of liver-derived EVs, no observed inflammatory infiltration and reduced specific miR “barcode.”

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.

Alcoholic liver disease: A current molecular and clinical perspective

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

Reversing Epigenetic Alterations Caused by Alcohol: A Promising Therapeutic Direction for Alcoholic Liver Disease

Alcoholic liver disease (ALD), a liver function disorder caused by excessive alcohol intake, is a serious threat to global public health and social development. Toxic metabolites and reactive oxygen species produced during the metabolism of alcohol can alter the epigenetic state including DNA methylation, histone modifications, and expression of microRNAs. Epigenetic alterations can conversely involve various signaling pathways, which could contribute to the initiation and progression of ALD. To elucidate the relationship between epigenetic alterations and alcohol damage not only reinforces our understanding on pathogenesis of ALD, but also provides novel targets for clinical diagnosis, treatment, and drug research of ALD. In this review, we have summarized the research progress of epigenetic alterations and related mechanisms caused by alcohol in the pathogenesis of ALD. Considering the invertibility of epigenetic alterations, treatment of ALD through epigenetic modification with common less harmful compounds is also related.

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.

Alcoholic liver disease

Alcoholic liver disease (ALD) is the most prevalent type of chronic liver disease worldwide. ALD can progress from alcoholic fatty liver (AFL) to alcoholic steatohepatitis (ASH), which is characterized by hepatic inflammation. Chronic ASH can eventually lead to fibrosis and cirrhosis and in some cases hepatocellular cancer (HCC). In addition, severe ASH (with or without cirrhosis) can lead to alcoholic hepatitis, which is an acute clinical presentation of ALD that is associated with liver failure and high mortality. Most individuals consuming >40 g of alcohol per day develop AFL; however, only a subset of individuals will develop more advanced disease. Genetic, epigenetic and non-genetic factors might explain the considerable interindividual variation in ALD phenotype. The pathogenesis of ALD includes hepatic steatosis, oxidative stress, acetaldehyde-mediated toxicity and cytokine and chemokine-induced inflammation. Diagnosis of ALD involves assessing patients for alcohol use disorder and signs of advanced liver disease. The degree of AFL and liver fibrosis can be determined by ultrasonography, transient elastography, MRI, measurement of serum biomarkers and liver biopsy histology. Alcohol abstinence achieved by psychosomatic intervention is the best treatment for all stages of ALD. In the case of advanced disease such as cirrhosis or HCC, liver transplantation may be required. Thus, new therapies are urgently needed.

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.

Pleiotropic functions of miR107 in cancer networks

MicroRNAs are short regulatory RNAs that posttranscriptionally modulate gene expression and thus play crucial roles in controlling cancer-onset, growth, and progression processes. miR107, a highly conserved microRNA that maps to intron 5 of the PANK1 gene, contributes to the regulation of normal and tumor biological processes. Studies have reported that miR107 has oncogenic or tumor-suppressor functions in different human tumors. The pleiotropic functions of miR107 in various cancers are achieved via its targeting different genes that are involved in tumor proliferation, invasiveness, metastasis, angiogenesis, and chemotherapy-response pathways. The carcinogenicity or cancer-suppressor effects of miR107 occur in a tissue- and cell-specific manner, and the expression level of miR107 can be affected by various factors, including epigenetic and genetic factors, treatment exposure, and daily diet. A comprehensive analysis of the current literature suggests that miR107 functions as a central element in the regulation of cancer networks and can be used as a potential diagnostic and prognostic biomarker and drug target for therapeutic intervention.

Colorectal Cancer and Alcohol Consumption-Populations to Molecules

Colorectal cancer (CRC) is a major cause of morbidity and mortality, being the third most common cancer diagnosed in both men and women in the world. Several environmental and habitual factors have been associated with the CRC risk. Alcohol intake, a common and rising habit of modern society, is one of the major risk factors for development of CRC. Here, we will summarize the evidence linking alcohol with colon carcinogenesis and possible underlying mechanisms. Some epidemiologic studies suggest that even moderate drinking increases the CRC risk. Metabolism of alcohol involves ethanol conversion to its metabolites that could exert carcinogenic effects in the colon. Production of ethanol metabolites can be affected by the colon microbiota, another recently recognized mediating factor to colon carcinogenesis. The generation of acetaldehyde and alcohol's other metabolites leads to activation of cancer promoting cascades, such as DNA-adduct formation, oxidative stress and lipid peroxidation, epigenetic alterations, epithelial barrier dysfunction, and immune modulatory effects. Not only does alcohol induce its toxic effect through carcinogenic metabolites, but alcoholics themselves are predisposed to a poor diet, low in folate and fiber, and circadian disruption, which could further augment alcohol-induced colon carcinogenesis.

The Role of miRNAs in the Pathophysiology of Liver Diseases and Toxicity

Both acute and chronic liver toxicity represents a major global health burden and an important cause of morbidity and lethality worldwide. Despite epochal progress in the treatment of hepatitis C virus infections, pharmacological treatment strategies for most liver diseases are still limited and new targets for prevention or treatment of liver disease are urgently needed. MicroRNAs (miRNAs) represent a new class of highly conserved small non-coding RNAs that are involved in the regulation of gene expression by targeting whole networks of so called “targets”. Previous studies have shown that the expression of miRNAs is specifically altered in almost all acute and chronic liver diseases. In this context, it was shown that miRNA can exert causal roles, being pro- or anti-inflammatory, as well as pro- or antifibrotic mediators or being oncogenes as well as tumor suppressor genes. Recent data suggested a potential therapeutic use of miRNAs by targeting different steps in the hepatic pathophysiology. Here, we review the function of miRNAs in the context of acute and chronic liver diseases. Furthermore, we highlight the potential role of circulating microRNAs in diagnosis of liver diseases and discuss the major challenges and drawbacks that currently prevent the use of miRNAs in clinical routine.

Epigenetic actions of environmental factors and promising drugs for cancer therapy

Carcinogenesis is known to be primarily associated with gene mutations. Recently, increasing evidence has suggested that epigenetic events also serve crucial roles in tumor etiology. Environmental factors, including nutrition, toxicants and ethanol, are involved in carcinogenesis through inducing epigenetic modifications, such as DNA methylation, histone deacetylase and miRNA regulation. Studying epigenetic mechanisms has facilitated the development of early diagnostic strategies and potential therapeutic avenues. Modulation at the epigenetic level, including reversing epigenetic modifications using targeted drugs, has demonstrated promise in cancer therapy. Therefore, identifying novel epigenetic biomarkers and therapeutic targets has potential for the future of cancer therapy. The present review discusses the environmental factors involved in epigenetic modifications and potential drug candidates for cancer therapy.

Fibrosis in small syngeneic rat liver grafts because of damaged bone marrow stem cells from chronic alcohol consumption

A patient with liver failure due to chronic and acute alcohol abuse under consideration for an urgent liver transplant shortly after stopping alcohol may have residual abnormalities that threaten transplant success, particularly for a small graft. To address this, we studied a model in which reduced-size (50%) Lewis rat livers are transplanted into green fluorescence protein transgenic Lewis recipients after they are fed alcohol or a control diet for 5 weeks. Here we show that normal small Lewis grafts transplanted to alcohol-fed Lewis hosts developed fibrosis, whereas no fibrosis was observed in control-fed recipients. Host-derived CD133 + 8-hydroxy-2'-deoxyguanosine (8-OHdG) cells were significantly increased in livers recovered from both alcohol-fed and control recipients, but only alcohol-fed recipients demonstrated co-staining (a marker of oxidative DNA damage). α smooth muscle actin (α-SMA) staining, a marker for myofibroblasts, also co-localized with CD133 + cells only in the livers of alcohol-fed recipients. Immunostaining and polymerase chain reaction analysis confirmed that chronic alcohol consumption decreased the proportion of bone marrow stem cells (BMSCs) expressing CD133, c-Kit, and chemokine (C-X-C motif) receptor 4 markers and caused oxidative mitochondria DNA (mtDNA) damage. Culture of CD133 + cells from normal rats with medium containing 3% ethanol for 48 hours resulted in elevated mitochondrial 8-OHdG and mtDNA deletion, and ethanol exposure diminished CD133 expression but dramatically increased α-SMA expression. In conclusion, oxidative mtDNA damage and deletions occur in BMSCs of chronic alcohol-fed recipients, and these damaged cells mobilize to the small liver grafts and become myofibroblasts where they play a key role in the subsequent development of fibrosis. Liver Transplantation 23 1564-1576 2017 AASLD.

WITHDRAWN: Epigenetics in Chronic Liver Disease

This article has been withdrawn at the request of the editors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Preliminary profiling of microRNA in the normal and regenerating liver of Chiloscyllium plagiosum

Liver is a vital organ present in animals for detoxification, protein synthesis, digestion and other functions and its powerful regenerative capacity is well known. C. plagiosum is an abundant fish that is representative of the cartilaginous class in the southeast coastal region of China and its liver accounts for >70% of the fish's visceral weight and contains many bioactive substances. MicroRNAs (microRNAs) play important roles in a wide range of biological processes in eukaryotes, including cell proliferation, differentiation, apoptosis. However, microRNAs in response to liver regeneration has not been well studied. This study aimed to identify the microRNAs that participate in liver regeneration and other liver-related diseases and to improve our understanding of the mechanisms of liver regeneration in sharks. To this end, normal and regenerating liver tissues from C. plagiosum were harvested 0, 3, 6, 12 and 24h after partial hepatectomy (pH) and were sequenced using the Illumina/Solexa platform. In total, 309 known microRNAs and 590 novel microRNAs were identified in C. plagiosum. There were many microRNAs differentially expressed in the normal and regenerating livers between time points. Using target prediction and GO analysis, most of the differentially expressed microRNAs were assigned to functional categories that may be involved in regulating liver regeneration, such as cell proliferation, differentiation and apoptosis. The microRNA expression profile of liver regeneration will pave the way for the development of effective strategies to fight against liver disease and other related disease.

Targeting inflammation for the treatment of alcoholic liver disease

Alcoholic liver disease (ALD) is a leading cause of chronic liver disease with a wide spectrum of manifestations including simple steatosis to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Liver injury in ALD is caused by chronic inflammation, which has been actively investigated as a therapeutic target for the treatment of ALD for over the last four decades. In this review, we summarize a wide variety of inflammatory mediators that have been shown to contribute to the pathogenesis of ALD, and discuss the therapeutic potential of these mediators for the treatment of ALD.

Human neutrophil peptide-1 promotes alcohol-induced hepatic fibrosis and hepatocyte apoptosis

BACKGROUND AND AIMS

Neutrophil infiltration of the liver is a typical feature of alcoholic liver injury. Human neutrophil peptide (HNP)-1 is an antimicrobial peptide secreted by neutrophils. The aim of this study was to determine if HNP-1 affects ethanol-induced liver injury and to examine the mechanism of liver injury induced by HNP-1.

METHODS

Transgenic (TG) mice expressing HNP-1 under the control of a β-actin-based promoter were established. Ethanol was orally administered to HNP-1 TG or wild-type C57BL/6N (WT) mice. SK-Hep1 hepatocellular carcinoma cells were used to investigate the effect of HNP-1 on hepatocytes in vitro.

RESULTS

After 24 weeks of ethanol intake, hepatic fibrosis and hepatocyte apoptosis were significantly more severe in TG mice than in WT mice. Levels of CD14, TLR4, and IL-6 in liver tissues were higher in TG mice than in WT mice. Apoptosis was accompanied by higher protein levels of caspase-3, caspase-8, and cleaved PARP in liver tissue. In addition, phosphorylated ASK1, ASK1, phosphorylated JNK, JNK1, JNK2, Bax, Bak and Bim were all more abundant in TG mice than in WT mice. In contrast, the level of anti-apoptotic Bcl2 in the liver was significantly lower in TG mice than in WT mice. Analysis of microRNAs in liver tissue showed that miR-34a-5p expression was significantly higher in TG mice than in WT mice. Furthermore, in the presence of ethanol, HNP-1 increased the apoptosis with the decreased level of Bcl2 in a concentration-dependent manner in vitro.

CONCLUSIONS

HNP-1 secreted by neutrophils may exacerbate alcohol-induced hepatic fibrosis and hepatocyte apoptosis with a decrease in Bcl2 expression and an increase in miR-34a-5p expression.

Blood hsa-miR-122-5p and hsa-miR-885-5p levels associate with fatty liver and related lipoprotein metabolism-The Young Finns Study

MicroRNAs are involved in disease development and may be utilized as biomarkers. We investigated the association of blood miRNA levels and a) fatty liver (FL), b) lipoprotein and lipid pathways involved in liver lipid accumulation and c) levels of predicted mRNA targets in general population based cohort. Blood microRNA profiling (TaqMan OpenArray), genome-wide gene expression arrays and nuclear magnetic resonance metabolomics were performed for Young Finns Study participants aged 34–49 years (n = 871). Liver fat status was assessed ultrasonographically. Levels of hsa-miR-122-5p and -885-5p were up-regulated in individuals with FL (fold change (FC) = 1.55, p = 1.36 * 10⁻¹⁴ and FC = 1.25, p = 4.86 * 10⁻⁴, respectively). In regression model adjusted with age, sex and BMI, hsa-miR-122-5p and -885-5p predicted FL (OR = 2.07, p = 1.29 * 10⁻⁸ and OR = 1.41, p = 0.002, respectively). Together hsa-miR-122-5p and -885-5p slightly improved the detection of FL beyond established risk factors. These miRNAs may be associated with FL formation through the regulation of lipoprotein metabolism as hsa-miR-122-5p levels associated with small VLDL, IDL, and large LDL lipoprotein subclass components, while hsa-miR-885-5p levels associated inversely with XL HDL cholesterol levels. Hsa-miR-885-5p levels correlated inversely with oxysterol-binding protein 2 (OSBPL2) expression (r = −0.143, p = 1.00 * 10⁻⁴) and suppressing the expression of this lipid receptor and sterol transporter could link hsa-miR-885-5p with HDL cholesterol levels.

Inhibition of miR-21 rescues liver regeneration after partial hepatectomy in ethanol-fed rats

Liver regeneration is a clinically significant tissue repair process that is suppressed by chronic alcohol intake through poorly understood mechanisms. Recently, microRNA-21 (miR-21) has been suggested to serve as a crucial microRNA (miRNA) regulator driving hepatocyte proliferation after partial hepatectomy (PHx) in mice. However, we reported recently that miR-21 is significantly upregulated in ethanol-fed rats 24 h after PHx, despite inhibition of cell proliferation, suggesting a more complex role for this miRNA. Here, we investigate how inhibition of miR-21 in vivo affects the early phase of liver regeneration in ethanol-fed rats. Chronically ethanol-fed rats and pair-fed control animals were treated with AM21, a mixed locked nucleic acid-DNA analog antisense to miR-21 that inhibited miR-21 in vivo to undetectable levels. Liver regeneration after PHx was followed by cell proliferation marker and gene expression analysis, miRNA profiling, and cell signaling pathway analysis. Although liver regeneration was not significantly impaired by AM21 in chow-fed rats, AM21 treatment in ethanol-fed animals completely restored regeneration and enhanced PHx-induced hepatocyte proliferation to levels comparable to those of untreated or chow-fed animals. In addition, a marked deposition of α-smooth muscle actin, a marker of stellate cell activation, which was evident in ethanol-treated animals after PHx, was effectively suppressed by AM21 treatment. Gene expression analysis further indicated that suppression of stellate cell-specific profibrogenic profiles and the Notch signaling contributed to AM21-mediated rescue from deficient hepatocyte proliferation in ethanol-fed animals. Our results indicate that the impact of miR-21 balances proproliferative effects with antiproliferative profibrogenic actions in regulating distinctive regenerative responses in normal vs. disease conditions.

Plasma miR-142 accounting for the missing heritability of CYP3A4/5 functionality is associated with pharmacokinetics of clopidogrel

AIM

To investigate whether plasma miRNAs targeting CYP3A4/5 have an impact on the variance of pharmacokinetics of clopidogrel.

MATERIALS & METHODS

The contribution of 13 miRNAs to the CYP3A4/5 gene expression and activity was investigated in 55 liver tissues. The association between plasma miRNAs targeting CYP3A4/5 mRNA and clopidogrel pharmacokinetics was analyzed in 31 patients with coronary heart disease who received 300 mg loading dose of clopidogrel.

RESULTS

Among 13 miRNAs, miR-142 was accounting for 12.2% (p = 0.002) CYP3A4 mRNA variance and 9.4% (p = 0.005) CYP3A5 mRNA variance, respectively. Plasma miR-142 was negatively associated with H4 Cmax (r = -0.5269; p = 0.0040) and associated with H4 AUC0-4h (r = -0.4986; p = 0.0069) after 300 mg loading dose of clopidogrel in coronary heart disease patients.

CONCLUSION

miR-142 could account for a part of missing heritability of CYP3A4/5 functionality related to clopidogrel activation.

Pathogenesis of Alcoholic Liver Disease

Alcoholic liver disease includes a broad clinical-histological spectrum from simple steatosis, cirrhosis, acute alcoholic hepatitis with or without cirrhosis to hepatocellular carcinoma as a complication of cirrhosis. The pathogenesis of alcoholic liver disease can be conceptually divided into (1) ethanol-mediated liver injury, (2) inflammatory immune response to injury, (3) intestinal permeability and microbiome changes. Corticosteroids may improve outcomes, but this is controversial and probably only impacts short-term survival. New pathophysiology-based therapies are under study, including antibiotics, caspase inhibition, interleukin-22, anakinra, FXR agonist and others. These studies provide hope for better future outcomes for this difficult disease.

Lin28 and let-7: roles and regulation in liver diseases

The diagnosis and treatment of liver disease remain a major health concern worldwide because of the diverse etiologies of this disease. For this reason, new therapeutic targets are greatly needed to halt the progression of this damaging disease. Upon initiation of liver injury by viral infection, autoimmune disease or toxin, and/or hepatitis, chronic disease may develop, which can progress to cirrhosis, hepatocellular carcinoma (HCC), cholangiocarcinoma, liver failure, or death. The Lin28/lethal-7 (let-7) molecular switch has emerged as a central regulator of multiorgan injuries and cancer development. Lin28 is a stem cell marker vital to initiation or maintenance of a stem cell phenotype. Lin28 has not been extensively studied in the liver, despite its ability to induce tissue regeneration via reprogramming of oxidative enzymes in other tissues and its involvement with numerous upstream regulators and downstream targets in liver disease. Theoretically, overexpression of Lin28 in certain forms of liver disease could be a potential treatment that aids in liver regeneration. Alternatively, Lin28 has been implicated numerous times in the progression of diverse cancer types and is associated with increased severity of disease. In this case, Lin28 could be a potential inhibitory target to prevent malignant transformation in the liver. This review seeks to characterize the role of Lin28 in liver disease.

Altered regulation of miR-34a and miR-483-3p in alcoholic hepatitis and DDC fed mice

MicroRNAs are small noncoding RNAs that negatively regulate gene expression by binding to the untranslated regions of their target mRNAs. Deregulation of miRNAs is shown to play pivotal roles in tumorigenesis and progression. Mallory-Denk Bodies (MDBs) are prevalent in various liver diseases including alcoholic hepatitis (AH) and are formed in mice livers by feeding DDC. By comparing AH livers where MDBs had formed with normal livers, there were significant changes of miR-34a and miR-483-3p by RNA sequencing (RNA-Seq) analyses. Real-time PCR further shows a 3- and 6-fold upregulation (respectively) of miR-34a in the AH livers and in the livers of DDC re-fed mice, while miR-483-3p was significantly downregulated in AH and DDC re-fed mice livers. This indicates that miR-34a and miR-483-3p may be crucial for liver MDB formation. P53 mRNA was found to be significantly downregulated both in the AH livers and in the livers of DDC re-fed mice, indicating that the upregulation of miR-34a is permitted by the decrease of p53 in AH since miR-34a is a main target of p53. Overexpression of miR-34a leads to an increase of p53 targets such as p27, which inhibits the cell cycle leading to cell cycle arrest. Importantly, BRCA1 is a target gene of miR-483-3p by RNA-Seq analyses and the downregulation of miR-483-3p may be the mechanism for liver MDB formation since the BRCA1 signal was markedly upregulated in AH livers. These results constitute a demonstration of the altered regulation of miR-34a and miR-483-3p in the livers of AH and mice fed DDC where MDBs formed, providing further insight into the mechanism of MDB formation mediated by miR-34a and miR-483-3p in AH.

Chronic alcohol drinking: Liver and pancreatic cancer?

Cancer is a multifactorial disease that results from complex interactions of numerous risk factors - genetic and environmental - over time, eventually leading to the diseased phenotypes. Thus, while epidemiological studies can point to risk factors, they cannot determine cause and effect relationships, and are unable to give biological and clinical insights into carcinogenesis. The link between any risk factor and carcinogenesis needs to be validated in experimental models. This is particularly true in epidemiological studies on alcohol consumption and its consequences. While there is no doubt that heavy alcohol consumption has devastating health effects, the inconsistencies in alcohol-related epidemiological studies and cancer suffer from possible sources of the variability in outcomes, ranging from inaccuracy of self-report of consumption to the problem of correlating cancer that started decades earlier to current or recent alcohol consumption. To further study the interactions between alcohol and cancer, the use of "Molecular Pathological Epidemiology" (MPE) advocated by Ogino et al. for dissecting the interplay between etiological factors, cellular and molecular characteristics, and disease progression in cancer is appropriate. MPE does not consider cancer as a single entity, rather it integrates analyses of epidemiological studies with the macroenvironment and molecular and microenvironment. This approach allows investigating the relationships between potential etiological agents and cancer based on molecular signatures. More research is needed to fully elucidate the link between heavy alcohol consumption and pancreatic cancer, and to further investigate the roles of acetaldehyde and FAEEs in pancreatic carcinogenesis.

MicroRNAs as Signaling Mediators and Biomarkers of Drug- and Chemical-Induced Liver Injury

Drug-induced liver injury (DILI) is major problem for both the drug industry and for clinicians. There are two basic categories of DILI: intrinsic and idiosyncratic. The former is the chief cause of acute liver failure in several developed countries, while the latter is the most common reason for post-marketing drug withdrawal and a major reason for failure to approve new drugs in the U.S. Although considerably more progress has been made in the study of intrinsic DILI, our understanding of both forms of drug hepatotoxicity remains incomplete. Recent work involving microRNAs (miRNAs) has advanced our knowledge of DILI in two ways: (1) possible roles of miRNAs in the pathophysiological mechanisms of DILI have been identified, and (2) circulating miRNA profiles have shown promise for the detection and diagnosis of DILI in clinical settings. The purpose of this review is to summarize major findings in these two areas of research. Taken together, exciting progress has been made in the study of miRNAs in DILI. Possible mechanisms through which miRNA species contribute to the basic mechanisms of DILI are beginning to emerge, and new miRNA-based biomarkers have the potential to greatly improve diagnosis of liver injury and prediction of patient outcomes.

Revisiting Chaos Theorem to Understand the Nature of miRNAs in Response to Drugs of Abuse

Just like Matryoshka dolls, biological systems follow a hierarchical order that is based on dynamic bidirectional communication among its components. In addition to the convoluted inter-relationships, the complexity of each component spans several folds. Therefore, it becomes rather challenging to investigate phenotypes resulting from these networks as it requires the integration of reductionistic and holistic approaches. One dynamic system is the transcriptome which comprises a variety of RNA species. Some, like microRNAs, have recently received a lot of attention. miRNAs are very pleiotropic and have been considered as therapeutic and diagnostic candidates in the biomedical fields. In this review, we survey miRNA profiles in response to drugs of abuse (DA) using 118 studies. After providing a summary of miRNAs related to substance use disorders (SUD), general patterns of miRNA signatures are compared among studies for single or multiple drugs of abuse. Then, current challenges and drawbacks in the field are discussed. Finally, we provide support for considering miRNAs as a chaotic system in normal versus disrupted states particularly in SUD and propose an integrative approach for studying and analyzing miRNA data.

Alcoholic liver disease: mechanisms of injury and targeted treatment

Alcoholic liver disease (ALD) is a complex process that includes a wide spectrum of hepatic lesions, from steatosis to cirrhosis. Cell injury, inflammation, oxidative stress, regeneration and bacterial translocation are key drivers of alcohol-induced liver injury. Alcoholic hepatitis is the most severe form of all the alcohol-induced liver lesions. Animal models of ALD mainly involve mild liver damage (that is, steatosis and moderate inflammation), whereas severe alcoholic hepatitis in humans occurs in the setting of cirrhosis and is associated with severe liver failure. For this reason, translational studies using humans and human samples are crucial for the development of new therapeutic strategies. Although multiple attempts have been made to improve patient outcome, the treatment of alcoholic hepatitis is still based on abstinence from alcohol and brief exposure to corticosteroids. However, nearly 40% of patients with the most severe forms of alcoholic hepatitis will not benefit from treatment. We suggest that future clinical trials need to focus on end points other than mortality. This Review discusses the main pathways associated with the progression of liver disease, as well as potential therapeutic strategies targeting these pathways.

MicroRNA responses to environmental liver carcinogens: Biological and clinical significance

A large number of biological, chemical, and dietary factors have been implicated in the development of liver cancer. These involve complex and protracted interactions between genetic, epigenetic, and environmental factors. The survival rate for patients diagnosed with late-stage liver cancer is currently low due to the aggressive nature of the disease and resistance to therapy. An increasing body of evidence has offered support for the crucial role of non-coding microRNA (miRNA) in directing hepatic responses to environmental risk factors for liver cancer. In this review we focus on miRNA responses to environmental liver cancer risk factors and their potential biological and clinical significance.

Chronic alcohol exposure differentially affects activation of female locus coeruleus neurons and the subcellular distribution of corticotropin releasing factor receptors

Understanding the neurobiological bases for sex differences in alcohol dependence is needed to help guide the development of individualized therapies for alcohol abuse disorders. In the present study, alcohol-induced adaptations in (1) anxiety-like behavior, (2) patterns of c-Fos activation and (3) subcellular distribution of corticotropin releasing factor receptor in locus coeruleus (LC) neurons was investigated in male and female Sprague-Dawley rats that were chronically exposed to ethanol using a liquid diet. Results confirm and extend reports by others showing that chronic ethanol exposure produces an anxiogenic-like response in both male and female subjects. Ethanol-induced sex differences were observed with increased c-Fos expression in LC neurons of female ethanol-treated subjects compared to controls or male subjects. Results also reveal sex differences in the subcellular distribution of the CRFr in LC-noradrenergic neurons with female subjects exposed to ethanol exhibiting a higher frequency of plasmalemmal CRFrs. These adaptations have implications for LC neuronal activity and its neural targets across the sexes. Considering the important role of the LC in ethanol-induced activation of the hypothalamo-pituitary-adrenal (HPA) axis, the present results indicate important sex differences in feed-forward regulation of the HPA axis that may render alcohol dependent females more vulnerable to subsequent stress exposure.

New advances in molecular mechanisms and emerging therapeutic targets in alcoholic liver diseases

Alcoholic liver disease is a major health problem in the United States and worldwide. Chronic alcohol consumption can cause steatosis, inflammation, fibrosis, cirrhosis and even liver cancer. Significant progress has been made to understand key events and molecular players for the onset and progression of alcoholic liver disease from both experimental and clinical alcohol studies. No successful treatments are currently available for treating alcoholic liver disease; therefore, development of novel pathophysiological-targeted therapies is urgently needed. This review summarizes the recent progress on animal models used to study alcoholic liver disease and the detrimental factors that contribute to alcoholic liver disease pathogenesis including miRNAs, S-adenosylmethionine, Zinc deficiency, cytosolic lipin-1β, IRF3-mediated apoptosis, RIP3-mediated necrosis and hepcidin. In addition, we summarize emerging adaptive protective effects induced by alcohol to attenuate alcohol-induced liver pathogenesis including FoxO3, IL-22, autophagy and nuclear lipin-1α.

Amygdalar neuronal plasticity and the interactions of alcohol, sex, and stress

Alcohol abuse and alcoholism are major medical problems affecting both men and women. Previous animal studies reported a difference in c-Fos neuronal activation after chronic alcohol exposure; however, females remain an understudied population. To model chronic alcohol exposure match-pair fed adult male and female rats were administered 14 days of a liquid ethanol containing diet. Analysis focused on the central nucleus of the amygdala (CeA), a region integral to stress sensitivity and substance abuse. Immunocytochemical approaches identified cells containing ΔFosB, a marker of sustained neuronal activation, and activity patterns within the CeA were mapped by subdivision and rostral-caudal extent. Significant interactions were present between all groups, with gender differences noted among control groups, and ethanol exposed animals having the greatest number of ΔFosB immunoreactive cells indicating baseline dysregulation. Compared with c-Fos, a marker of recent neuronal activation, male ethanol treated animals had similar activity to controls, indicating a neuronal habituation not seen in females. Next, a cohort of animals were exposed to the forced swim test (FST), and c-Fos was examined in addition to FST behavior. Neuronal activity was increased in ethanol exposed animals compared to controls, and control females compared to males, indicating a potentiated stress response. Further, a population of activated neurons were shown to contain either corticotropin releasing factor or enkephalin. The present data suggest that dysregulation in the CeA neuronal activity may underlie some of the negative sequelae of alcohol abuse, and may, in part, underlie the distinctive response seen between genders to alcohol use.