The progression of liver fibrosis is related with overexpression of the miR-199 and 200 families

miR-199a-5p Is upregulated during fibrogenic response to tissue injury and mediates TGFbeta-induced lung fibroblast activation by targeting caveolin-1

As miRNAs are associated with normal cellular processes, deregulation of miRNAs is thought to play a causative role in many complex diseases. Nevertheless, the precise contribution of miRNAs in fibrotic lung diseases, especially the idiopathic form (IPF), remains poorly understood. Given the poor response rate of IPF patients to current therapy, new insights into the pathogenic mechanisms controlling lung fibroblasts activation, the key cell type driving the fibrogenic process, are essential to develop new therapeutic strategies for this devastating disease. To identify miRNAs with potential roles in lung fibrogenesis, we performed a genome-wide assessment of miRNA expression in lungs from two different mouse strains known for their distinct susceptibility to develop lung fibrosis after bleomycin exposure. This led to the identification of miR-199a-5p as the best miRNA candidate associated with bleomycin response. Importantly, miR-199a-5p pulmonary expression was also significantly increased in IPF patients (94 IPF versus 83 controls). In particular, levels of miR-199a-5p were selectively increased in myofibroblasts from injured mouse lungs and fibroblastic foci, a histologic feature associated with IPF. Therefore, miR-199a-5p profibrotic effects were further investigated in cultured lung fibroblasts: miR-199a-5p expression was induced upon TGFβ exposure, and ectopic expression of miR-199a-5p was sufficient to promote the pathogenic activation of pulmonary fibroblasts including proliferation, migration, invasion, and differentiation into myofibroblasts. In addition, we demonstrated that miR-199a-5p is a key effector of TGFβ signaling in lung fibroblasts by regulating CAV1, a critical mediator of pulmonary fibrosis. Remarkably, aberrant expression of miR-199a-5p was also found in unilateral ureteral obstruction mouse model of kidney fibrosis, as well as in both bile duct ligation and CCl₄-induced mouse models of liver fibrosis, suggesting that dysregulation of miR-199a-5p represents a general mechanism contributing to the fibrotic process. MiR-199a-5p thus behaves as a major regulator of tissue fibrosis with therapeutic potency to treat fibroproliferative diseases.

Fibrosis is the final common pathway in virtually all forms of chronic organ failure, including lung, liver, and kidney, and is a leading cause of morbidity and mortality worldwide. Fibrosis results from the excessive activity of fibroblasts, in particular a differentiated form known as myofibroblast that is responsible for the excessive and persistent accumulation of scar tissue and ultimately organ failure. Idiopathic Lung Fibrosis (IPF) is a chronic and often rapidly fatal pulmonary disorder of unknown origin characterized by fibrosis of the supporting framework (interstitium) of the lungs. Given the poor prognosis of IPF patients, new insights into the biology of (myo)fibroblasts is of major interest to develop new therapeutics aimed at reducing (myo)fibroblast activity to slow or even reverse disease progression, thereby preserving organ function and prolonging life. MicroRNAs (miRNAs), a class of non-coding RNA recently identified, are associated with normal cellular processes; and deregulation of miRNAs plays a causative role in a vast array of complex diseases. In this study, we identified a particular miRNA: miR-199a-5p that governs lung fibroblast activation and ultimately lung fibrosis. Overall we showed that miR-199a-5p is a major regulator of fibrosis with strong therapeutic potency to treat fibroproliferative diseases such as IPF.

microRNAs in liver disease: from diagnostics to therapeutics

There is a need to identify effective biomarkers for diagnosis, prognosis and prediction of treatment efficacy for many liver diseases such as hepatocellular cancer, and chronic viral hepatitis. The identification of disease-specific alterations in microRNA expression and the ability to detect microRNAs in the circulation provide the basis for identifying novel clinically effective treatments and biomarkers. Knowledge regarding miRNA in human liver disease may eventually lead to serum or tissue biomarkers with clinical utility. A selection of relevant studies is reviewed. There are major challenges that need to be addressed prior to clinical application such as the need for careful validation of diagnostic miRNA candidates in well described clinical cohorts, and technical issues such as quantitation and standardization of assays. The rapid progress in therapeutic interventions using miRNA based strategies for chronic hepatitis C and hepatocellular cancer provides optimism for novel approaches that will build on the existing and emerging knowledge regarding miRNA in liver diseases.

Analysis of circulating microRNA by microarray in liver disease

MicroRNAs (miRNAs) are small, noncoding RNAs that regulate protein levels post-transcriptionally. miRNAs play important regulatory roles in many cellular processes, including differentiation, neoplastic transformation, and cell replication and regeneration. Aberrant expression of miRNAs has been linked to infectious and regenerative disease and carcinogenesis, among others. Recent studies as well have reported that significantly expressed miRNAs in serum are related to cancer and a range of infectious disease. With this in mind, several investigators have made attempts to apply circulating miRNAs as useful clinical biomarkers. In this chapter, we explore making diagnoses using miRNA expression pattern with the hope that this method will lead to higher levels of accuracy.

Prevention of hepatocellular carcinoma: potential targets, experimental models, and clinical challenges

Chronic fibrotic liver diseases such as viral hepatitis eventually develop liver cirrhosis, which causes occurrence of hepatocellular carcinoma (HCC). Given the limited therapeutic efficacy in advanced HCC, prevention of HCC development could be an effective strategy for improving patient prognosis. However, there is still no established therapy to meet the goal. Studies have elucidated a wide variety of molecular mechanisms and signaling pathways involved in HCC development. Genetically-engineered or chemically-treated experimental models of cirrhosis and HCC have been developed and shown their potential value in investigating molecular therapeutic targets and diagnostic biomarkers for HCC prevention. In this review, we overview potential targets of prevention and currently available experimental models, and discuss strategies to translate the findings into clinical practice.

Comprehensive miRNA expression analysis in peripheral blood can diagnose liver disease

Background

miRNAs circulating in the blood in a cell-free form have been acknowledged for their potential as readily accessible disease markers. Presently, histological examination is the golden standard for diagnosing and grading liver disease, therefore non-invasive options are desirable. Here, we investigated if miRNA expression profile in exosome rich fractionated serum could be useful for determining the disease parameters in patients with chronic hepatitis C (CHC).

Methodology

Exosome rich fractionated RNA was extracted from the serum of 64 CHC and 24 controls with normal liver (NL). Extracted RNA was subjected to miRNA profiling by microarray and real-time qPCR analysis. The miRNA expression profiles from 4 chronic hepatitis B (CHB) and 12 non alcoholic steatohepatitis (NASH) patients were also established. The resulting miRNA expression was compared to the stage or grade of CHC determined by blood examination and histological inspection.

Principal Findings

miRNAs implicated in chronic liver disease and inflammation showed expression profiles that differed from those in NL and varied among the types and grades of liver diseases. Using the expression patterns of nine miRNAs, we classified CHC and NL with 96.59% accuracy. Additionally, we could link miRNA expression pattern with liver fibrosis stage and grade of liver inflammation in CHC. In particular, the miRNA expression pattern for early fibrotic stage differed greatly from that observed in high inflammation grades.

Conclusions

We demonstrated that miRNA expression pattern in exosome rich fractionated serum shows a high potential as a biomarker for diagnosing the grade and stage of liver diseases.

MicroRNAs, hepatitis C virus, and HCV/HIV-1 co-infection: new insights in pathogenesis and therapy

MicroRNAs (miRNAs) can exert a profound effect on Hepatitis C virus (HCV) replication. The interaction of HCV with the highly liver-enriched miRNA, miR-122 represents one such unique example of viruses having evolved mechanism(s) to usurp the host miRNA machinery to support viral life cycle. Furthermore, HCV infection can also trigger changes in the cellular miRNA profile, which may ultimately contribute to the outcome of viral infection. Accumulating knowledge on HCV-host miRNA interactions has ultimately influenced the design of therapeutic interventions against chronic HCV infection. The importance of microRNA modulation in Human Immunodeficiency Virus (HIV-1) replication has been reported, albeit only in the context of HIV-1 mono-infection. The development of HCV infection is dramatically influenced during co-infection with HIV-1. Here, we review the current knowledge on miRNAs in HCV mono-infection. In addition, we discuss the potential role of some miRNAs, identified from the analyses of public data, in HCV/HIV-1 co-infection.

Modulation of immune responses following solid organ transplantation by microRNA

Organ transplantation, an accepted treatment for end stage organ failure, is often complicated by allograft rejection and disease recurrence. In this review we will discuss the potential role of microRNAs in allograft immunity especially leading to rejection of the transplanted organ. microRNAs (miRNAs), originally identified in C. elegans, are short non-coding 21-24 nucleotide sequences that bind to its complementary sequences in functional messenger RNAs and inhibits post-translational processes through RNA duplex formation resulting in gene silencing (Lau et al., 2001). Gene specific translational silencing by miRNAs regulates pathways for immune responses such as development of innate immunity, inflammation, T-cell and B-cell differentiation and signaling that are implicated in various stages of allograft rejection. miRNAs also play a role in development of post-transplant complicacies like fibrosis, cirrhosis, carcinogenesis often leading to graft loss and poor patient outcome. Recent advancements in the methods for detecting and quantifying miRNA in tissue biopsies, as well as in serum and urine samples, has led to identification of specific miRNA signatures in patients with allograft rejection and have been utilized to predict allograft status and survival. Therefore, miRNAs play a significant role in post-transplant events including allograft rejection, disease recurrence and tumor development impacting patient outcome.

MicroRNA signatures of iPSCs and endoderm-derived tissues

MicroRNAs (miRNAs), small non-coding RNAs that fine-tune gene expression, play multiple roles in the cell, including cell fate specification. We have analyzed the differential expression of miRNAs during fibroblast reprogramming into induced pluripotent stem cells (iPSCs) and endoderm induction from iPSCs upon treatment with high concentrations of Activin-A. The reprogrammed iPSCs assumed an embryonic stem cell (ESC)-like miRNA signature, marked by the induction of pluripotency clusters miR-290-295 and miR-302/367 and conversely the downregulation of the let-7 family. On the other hand, endoderm induction in iPSCs resulted in the upregulation of 13 miRNAs. Given that the liver and the pancreas are common derivatives of the endoderm, analysis of the expression of these 13 upregulated miRNAs in hepatocytes and pancreatic islets revealed a tendency for these miRNAs to be expressed more in pancreatic islets than in hepatocytes. These observations provide insights into how differentiation may be guided more efficiently towards the endoderm and further into the liver or pancreas. Moreover, we also report novel miRNAs enriched for each of the cell types analyzed.

[MicroRNAs in hepatocarcinogenesis]

The details of molecular alterations occurring during hepatocarcinogenesis have not been revealed yet. Nevertheless, it is known that microRNAs (miRNA), these short RNA molecules regulating gene expression mainly in a negative way, are also involved in this process. Altered miRNA expression levels are present in liver diseases when compared with normal liver tissue, and the observed alterations depend mainly on which is more advantegous for the disease: activation or inhibition of the genes (e.g. oncogenes or tumor suppressor genes) regulated by the altered miRNAs. The miRNA expression pattern described in hepatocellular carcinoma seems to differ the most from that found in the normal liver; however, remarkable alterations at miRNA levels have been published in early stages of hepatic tumor progression such as fibrosis and chronic hepatitis. For example, the expression of miR-21, miR-221, miR-222 and miR-199a showing characteristic alterations in hepatocellular carcinoma also displayed deregulated expressions in these two early stages. The liver characteristic miRNA, miR-122, usually exhibits a decreased expression level upon liver injury as well as miR-122 expression tends to decrease as hepatic carcinogenesis progresses. Besides, miR-122 enhances the replication of hepatitis C virus and the initial low or high level of miR-122 seems to influence the efficiency of interferon therapy. Recently, statistically significant differences have been detected in the expression of several miRNAs being present in the serum of patients with chronic hepatitis, chirrhosis and hepatocellular carcinoma when compared with normal controls. It suggests that serum miRNAs could be potential biomarkers. In this article, the major and recent alterations of microRNA expression patterns in stages of hepatocarcinogenesis such as fibrosis, viral infections (hepatitis), cirrhosis and hepatocellular carcinoma are summarized.

The potential of microRNAs in liver fibrosis

MicroRNAs (miRNAs) are a class of ~22-nucleotides noncoding RNAs that regulate gene expression by specifically binding with 3'-untranslated region (3'-UTR) of target gene mRNAs to posttranscriptionally effect mRNA stability and translation,and play essential roles in a variety of biological processes, including cell development, proliferation, differentiation, and apoptosis. Liver fibrosis is the occurrence of liver cell necrosis and inflammatory stimulation, and is characterized by excessive accumulation of extracellular matrices(ECMs). In the fibrotic liver, hepatic stellate cells (HSCs), which are regulated by multiple signal transduction pathways, undergo myofibroblastic transdifferentiation and are generally regarded as the major ECM producer responsible for liver fibrosis. A growing body of evidence suggests that divergent miRNAs participate in liver fibrotic process and activation of HSC. Moreover, members of many signal transduction pathways are important targets for miRNAs. In this review, we make a summary on current understanding of the roles of miRNAs in the development of liver fibrosis, HSC functions and their potential as novel drug targets.

MicroRNA silencing and the development of novel therapies for liver disease

In recent years microRNAs have emerged as crucial small non-coding RNA molecules with diverse roles in various diseases including diseases of the liver. In this review, we highlight the latest advances in the field of microRNA biology and their potential as emerging therapeutic targets in liver disease.

Induction of microRNA-214-5p in human and rodent liver fibrosis

Background

miRNAs are non-coding RNAs that regulate gene expression in a wide range of biological contexts, including a variety of diseases. The present study clarified the role of miR-214-5p in hepatic fibrogenesis using human clinical tissue samples, livers from rodent models, and cultured hepatic stellate cells.

Methods

The expression of miR-214-5p and genes that are involved in liver fibrosis were analyzed in hepatitis C virus-infected human livers, rodent fibrotic livers, a human stellate cell line (LX-2), and the cells from intact mouse livers using real-time PCR. The effect of miR-214-5p overexpression in LX-2 cells on cell function was investigated. Twist-1 expression in the liver tissues of mouse models and primary-cultured stellate cells was also analyzed.

Results

miR-214-5p was upregulated in human and mouse livers in a fibrosis progression–dependent manner. miR-214-5p expression increased during the culture-dependent activation of mouse primary stellate cells and was significantly higher in stellate cells than in hepatocytes. The overexpression of miR-214-5p in LX-2 cells increased the expression of fibrosis-related genes, such as matrix metalloproteinase (MMP)-2, MMP-9, α-smooth muscle actin, and transforming growth factor (TGF)-β1. TGF-β stimulation induced miR-214-5p in LX-2 cells. Twist-1 was increased in fibrotic mouse livers and induced during mouse stellate cell activation.

Conclusion

miR-214-5p may play crucial roles in the activation of stellate cells and the progression of liver fibrosis. Twist-1 may regulate miR-214-5p expression in the liver, particularly in stellate cells.

MicroRNAs: Small but amazing, and their association with endothelin

MicroRNAs (miRNAs) are small non-coding RNA molecules involved in the expressional regulation of genes by inhibiting gene translation. MicroRNAs are recruited and incorporated into the miRISC, ribonucleoprotein complex, targeting specific mRNAs through mechanisms specific for a miRNA sequence. Here we review the biogenesis, regulation, and monitoring of miRNAs, as well as the current evidence for potential roles of miRNAs in human diseases associated with activation of the endothelin system. These diseases include cancer, kidney disease, cardiovascular diseases, inflammatory diseases, infectious diseases, and blood diseases, that may all be aggravated by aberrant miRNA expression. In this review we will also discuss regulatory mechanisms determining production of miRNA as well as measuring or targeting miRNAs as potential novel approaches for diagnosis and treatment. Targeting miRNAs possibly will allow one to detect diseases or to interfere with the progression of diseases associated with activation of the endothelin system.

Role of MicroRNAs in Fibrosis

Fibrosis is the leading cause of organ dysfunction in diseases such as systemic sclerosis, liver cirrhosis, cardiac fibrosis, progressive kidney disease, and idiopathic pulmonary fibrosis. The hallmark of fibrosis is tissue remodeling with excess deposition of extracellular matrix components, predominantly collagens. Different cell types, cytokines, growth factors, and enzymes interact in complex pathogenic networks with myofibroblasts playing a pivotal role. MicroRNAs are small non-coding RNAs acting as negative regulators of gene expression at the post-transcriptional level. MicroRNAs have been associated with many basic cellular processes as well as with a wide spectrum of diseases, most notably cancer. This review provides a comprehensive overview of microRNAs regulating profibrotic pathways and extracellular matrix synthesis. The potential of miRNA for targeted therapeutic approaches in fibrotic disorders is also discussed.

MicroRNAs and hepatitis C virus: toward the end of miR-122 supremacy

The most common etiologic agents causing chronic hepatitis are hepatitis C and B viruses (HCV and HBV, respectively). Chronic infection caused by HCV is considered one of the major causative agents of liver cirrhosis and hepatocellular carcinoma worldwide. In combination with the increasing rate of new HCV infections, the lack of a current vaccine and/or an effective treatment for this virus continues to be a major public health challenge. The development of new treatments requires a better understanding of the virus and its interaction with the different components of the host cell. MicroRNAs (miRNAs) are small non-coding RNAs functioning as negative regulators of gene expression and represent an interesting lead to study HCV infection and to identify new therapeutic targets. Until now, microRNA-122 (miR-122) and its implication in HCV infection have been the focus of different published studies and reviews. Here we will review recent advances in the relationship between HCV infection and miRNAs, showing that some of them emerge in publications as challengers against the supremacy of miR-122.

Anti-fibrotic therapy: lost in translation?

While preclinical development of potential anti-fibrotics is far advanced, with numerous pharmacological targets and promising agents, almost none has entered clinical validation. Reasons are manifold, including the usually slow progression of liver fibrosis, requiring high numbers of well-stratified patients undergoing long-term treatment when conventional liver biopsy based parameters or hard liver-related endpoints are used. Importantly, there is a notorious lack of sensitive and specific surrogate markers or imaging technologies for liver fibrosis progression or regression that would permit a rapid clinical screening for potential anti-fibrotics. Nonetheless, in view of an urgent need for anti-fibrotics that positively impact morbidity and mortality from chronic liver diseases, the field is now moving more quickly towards clinical translation. This development is driven by thoughtful preclinical validation, a better study design and improved surrogate readouts using currently available methodologies. Moreover, upcoming novel biomarkers and imaging technologies will soon permit a more exact and efficient assessment of fibrosis progression and regression.

MicroRNAs in liver disease

MicroRNAs are small noncoding RNA molecules that regulate gene expression posttranscriptionally through complementary base pairing with thousands of messenger RNAs. They regulate diverse physiological, developmental, and pathophysiological processes. Recent studies have uncovered the contribution of microRNAs to the pathogenesis of many human diseases, including liver diseases. Moreover, microRNAs have been identified as biomarkers that can often be detected in the systemic circulation. We review the role of microRNAs in liver physiology and pathophysiology, focusing on viral hepatitis, liver fibrosis, and cancer. We also discuss microRNAs as diagnostic and prognostic markers and microRNA-based therapeutic approaches for liver disease.

microRNA are Central Players in Anti- and Profibrotic Gene Regulation during Liver Fibrosis

MicroRNA (miRNA) are small non-coding RNA molecules that posttranscriptionally effect mRNA stability and translation by targeting the 3'-untranslated region (3'-UTR) of various transcripts. Thus, dysregulation of miRNA affects a wide range of cellular processes such as cell proliferation and differentiation involved in organ remodeling processes. Divergent miRNA patterns were observed during chronic liver diseases of various etiologies. Chronic liver diseases result in uncontrolled scar formation ending up in liver fibrosis or even cirrhosis. Since it has been shown that miR-29 dysregulation is involved in synthesis of extracellular matrix proteins, miR-29 is of special interest. The importance of miR-29 in hepatic collagen homeostasis is underlined by in vivo data showing that experimental severe fibrosis is associated with a prominent miR-29 decrease. The loss of miR-29 is due to the response of hepatic stellate cells to exposure to the profibrogenic mediators TGF-β and PDGF-BB. Several putative binding sites for the Smad proteins and the Ap1 complex are located in the miR-29 promoter, which are suggested to mediate miR-29 decrease in fibrosis. Other miRNA are highly increased after profibrogenic stimulation, such as miR-21. miR-21 is transcriptionally upregulated in response to Smad-3 rather than Smad-2 activation after TGF-β stimulation. In addition, TGF-β promotes miR-21 expression by formation of a microprocessor complex containing Smad proteins. Elevated miR-21 may then act as a profibrogenic miRNA by its repression of the TGF-β inhibitory Smad-7 protein.

Plasma microRNA profiles in rat models of hepatocellular injury, cholestasis, and steatosis

MicroRNAs (miRNAs) are small RNA molecules that function to modulate the expression of target genes, playing important roles in a wide range of physiological and pathological processes. The miRNAs in body fluids have received considerable attention as potential biomarkers of various diseases. In this study, we compared the changes of the plasma miRNA expressions by acute liver injury (hepatocellular injury or cholestasis) and chronic liver injury (steatosis, steatohepatitis and fibrosis) using rat models made by the administration of chemicals or special diets. Using miRNA array analysis, we found that the levels of a large number of miRNAs (121-317 miRNAs) were increased over 2-fold and the levels of a small number of miRNAs (6-35 miRNAs) were decreased below 0.5-fold in all models except in a model of cholestasis caused by bile duct ligation. Interestingly, the expression profiles were different between the models, and the hierarchical clustering analysis discriminated between the acute and chronic liver injuries. In addition, miRNAs whose expressions were typically changed in each type of liver injury could be specified. It is notable that, in acute liver injury models, the plasma level of miR-122, the most abundant miRNA in the liver, was more quickly and dramatically increased than the plasma aminotransferase level, reflecting the extent of hepatocellular injury. This study demonstrated that the plasma miRNA profiles could reflect the types of liver injury (e.g. acute/chronic liver injury or hepatocellular injury/cholestasis/steatosis/steatohepatitis/fibrosis) and identified the miRNAs that could be specific and sensitive biomarkers of liver injury.

Serum miR-483-5p as a potential biomarker to detect hepatocellular carcinoma

BACKGROUND AND GOALS

There are no highly sensitive and specific minimally invasive biomarkers for hepatocellular carcinoma (HCC) to date. The objective of this study was to identify serum microRNAs (miRNAs) as potential HCC biomarkers.

METHODS

Using miRCURY LNA™ microRNA arrays, the levels of circulating miRNAs in the serum of patients with HCC were compared and controls were matched. Then 253 subjects (112 HCC, 85 chronic hepatitis B [CHB], and 56 healthy controls) were recruited and 12 serum miRNAs were compared by quantitative real-time polymerase chain reaction (qRT-PCR). It was followed by the comparison of serum miRNA concentrations before and after the surgical resection in HCC group.

RESULTS

Median levels of miR-483-5p and miR-500a were higher in HCC patients than in patients with CHB and in healthy controls (p < 0.0001), but there were no differences between CHB patients and healthy controls (p > 0.05) and miR-483-5p levels were significantly reduced in serum samples obtained 30 days after surgical resection (p < 0.0001). The area under receiver operating characteristic curves of miR-483-5p and miR-500a was 74% (cutoff [Ct] value = 2.824, sensitivity = 74%, and specificity = 66%) and 66% (Ct value = 1.830, sensitivity = 74%, and specificity = 51%) for the prediction of HCC, respectively. In detecting HCC, combining α-fetoprotein (AFP) and serum miR-483-5p (sensitivity = 81% and specificity = 83%) was better than AFP alone (sensitivity = 78%, specificity = 70%).

CONCLUSION

Our observations suggest that serum miR-483-5p and miR-500a might serve as novel, noninvasive biomarkers for HCC. Serum miR-483-5p might complement AFP in detecting HCC.

miR-200b is involved in intestinal fibrosis of Crohn's disease

Intestinal fibrosis is one of the major serious complications of Crohn’s disease (CD). However, there are no effective antifibrotic drugs to treat intestinal fibrosis in CD. Therefore, it is important to understand the pathogenesis of fibrosis in CD. It has been reported that members of the miR-200 family are essential in the regulation of renal fibrogenesis. In this study, we analyzed the function of miR-200a and miR-200b in intestinal fibrosis, which was induced by transforming growth factor β1 (TGF-β1) in vitro. Furthermore, we detected the expression of miR-200a and miR-200b in CD specimens, which were divided into groups of fibrosis and no-fibrosis. The results of this study showed that administration of miR-200b could partially protect intestinal epithelial cells from fibrogenesis in vitro. Furthermore, we found that miR-200b was overexpressed in the serum of the fibrosis group. The results suggest that miR-200b has potential value for diagnostic and therapeutic applications for CD patients with fibrosis complications.

Roles of microRNAs in the liver

MicroRNAs (miRNAs) are a group of small non-coding RNAs that function as endogenous silencers of numerous target genes. Hundreds of human miRNAs have been identified in the human genome, and they are expressed in a tissue-specific manner and play important roles in cell proliferation, apoptosis, and differentiation. Numerous studies have shown that miRNAs participate in a variety of physiological and pathological processes in the liver. In this review, we will discuss the roles of miRNAs in the processes of liver regeneration (LR), liver immune responses, and the pathogenesis of liver fibrosis and hepatocellular carcinoma (HCC).

Expression of p53 in the effects of artesunate on induction of apoptosis and inhibition of proliferation in rat primary hepatic stellate cells

Background

Activation of hepatic stellate cells (HSCs) plays an important role in the development of cirrhosis through the increased production of collagen. p53, the “guardian of the genome”, is a transcription factor that can bind to promoter regions of hundreds of genes where it either activates or suppresses gene expression. Thereby, p53 serves as a tumor suppressor by inducing cell cycle arrest, apoptosis, senescence and DNA repair. Artesunate is a derivative of Artemisinin, Scholars had found it had more extensive pharmacological effects past 10 years. However, little is known about the expression of p53 in the effects of Artesunate on induction of apoptosis and inhibition of proliferation in rat HSCs.

Methodology/Principal Findings

Isolated and cultured rat primary HSCs in the flask for 10 days to make cells activated. HSCs were divided into two groups: experimental groups and control groups, experimental groups included with various concentrations of Artesunate (125, 150, 175, 200, 225 µmol/L) for 24, 48 and 72 hours. Analysis of MTT revealed that activated HSCs treated with various concentrations of Artesunate (150–225 µmol/L) were inhibited on dose and time-effect relationships; Concentration of hydroxyproline in supernatant was detected by digestive method; Analysis of flow cytometry demonstrated that Artesunate could arrest cell cycle in G1 and induce apoptosis; The nuclear morphological changes in apoptotic cells were evaluated with DNA staining by Hoechst 33258 dye; The expression of p53 were up-regulated showed by western blotting and RT-PCR.

Conclusion

Artesunate could inhibit HSCs proliferation in dose-dependent and time-dependent manners in vitro through increase the expression of p53.

Role of microRNAs in the reperfused myocardium towards post-infarct remodelling

Myocardial ischaemia/reperfusion (I/R)-induced remodelling generally includes cell death (necrosis and apoptosis), myocyte hypertrophy, angiogenesis, cardiac fibrosis, and myocardial dysfunction. It is becoming increasingly clear that microRNAs (miRNAs or miRs), a group of highly conserved small (∼18-24 nucleotide) non-coding RNAs, fulfil specific functions in the reperfused myocardium towards post-infarct remodelling. While miR-21, -133, -150, -195, and -214 regulate cardiomyocyte hypertrophy, miR-1/-133 and miR-208 have been elucidated to influence myocardial contractile function. In addition, miR-21, -24, -133, -210, -494, and -499 appear to protect myocytes against I/R-induced apoptosis, whereas miR-1, -29, -199a, and -320 promote apoptosis. Myocardial fibrosis can be regulated by the miR-29 family and miR-21. Moreover, miR-126 and miR-210 augment I/R-induced angiogenesis, but miR-24, -92a, and -320 suppress post-infarct neoangiogenesis. In this review, we summarize the latest advances in the identification of myocardial ischaemia-associated miRNAs and their functional significance in the modulation of I/R-triggered remodelling. Controversial effects of some miRNAs in post-infarct remodelling will be also discussed.

MicroRNAs in hepatic pathophysiology in diabetes

MicroRNAs (miRNAs or miRs) are small approximately 22 nucleotide RNA species that are believed to regulate diverse metabolic and physiological processes. In the recent past, several reports have surfaced that demonstrate the role of miRNAs in various biological processes and numerous disease states. For a disease as complex as diabetes, the emergence of miRNAs as key regulators leading to the disease phenotype has added a novel dimension to the area of diabetes research. On the other hand, the liver, a metabolic hub, contributes in a major way towards maintaining normal glucose levels in the body as it can both stimulate and inhibit hepatic glucose output. This equilibrium is frequently disturbed in diabetes and hence, the liver assumes special significance considering the correlation between altered hepatic physiology and diabetes. While the understanding of the mechanisms behind this altered hepatic behavior is not yet completely understood, recent reports on the status and role of miRNAs in the diabetic liver have further added to the complexities of the knowledge of hepatic pathophysiology in diabetes. Here, we bring together the various miRNAs that play a role in the altered hepatic behavior during diabetes.

Banking on the future: biobanking for "omics" approaches to biomarker discovery for Opisthorchis-induced cholangiocarcinoma in Thailand

Cholangiocarcinoma (CCA)--bile duct cancer--is associated with late presentation, poses challenges for diagnosis, and has high mortality. These features t highlight the desperate need for biomarkers than can be measured early and in accessible body fluids such as plasma of people at risk for developing this lethal cancer. In this manuscript, we address previous limitations in the discovery stage of biomarker(s) for CCA and indicate how new generation of "omics" technologies could be used for biomarker discovery in Thailand. A key factor in the success of this biomarker program for CCA is the combination of cutting edge technology with strategic sample acquisition by a biorepositories.