Non-coding RNAs in hepatitis C-induced hepatocellular carcinoma:Dysregulation and implications for early detection,diagnosis and therapy

Hepatitis C virus(HCV)infection is one of main causes of hepatocellular carcinoma(HCC)and the prevalence of HCV-associated HCC is on the rise worldwide.It is particularly important and helpful to identify potential markers for screening and early diagnosis of HCC among high-risk individuals with chronic hepatitis C,and to identify target molecules for the prevention and treatment of HCV-associated-HCC.Small noncoding RNAs,mainly microRNAs(miRNAs),and long non-coding RNAs(lncRNAs)with size greater than 200nucleotides,are likely to play important roles in a variety of biological processes,including development and progression of HCC.For the most part their underlying mechanisms of action remain largely unknown.In recent years,with the advance of high-resolution of microarray and application of next generation sequencing techniques,a significant number of non-coding RNAs(ncRNAs)associated with HCC,particularly caused by HCV infection,have been found to be differentially expressed and to be involved in pathogenesis of HCVassociated HCC.In this review,we focus on recent studies of ncRNAs,especially miRNAs and lncRNAs related to HCV-induced HCC.We summarize those ncRNAs aberrantly expressed in HCV-associated HCC and highlight the potential uses of ncRNAs in early detection,diagnosis and therapy of HCV-associated HCC.We also discuss the limitations of recent studies,and suggest future directions for research in the field.miRNAs,lncRNAs and their target genes may represent new candidate molecules for the prevention,diagnosis and treatment of HCC in patients with HCV infection.Studies of the potential uses of miRNAs and lncRNAs as diagnostic tools or therapies are still in their infancy.

Heme status affects human hepatic messenger RNA and microRNA expression

AIM:To assess effects of heme on messenger RNA(mRNA) and microRNA(miRNA) profiles of liver cells derived from humans.METHODS:We exposed human hepatoma cell line Huh-7 cells to excess iron protoporphyrin(heme)(10 μmol/L) or induced heme deficiency by addition of 4,6-dioxoheptanoic acid(500 μmol/L),a potent inhibitor of aminolevulinic acid dehydratase,for 6 h or 24 h.We harvested total RNA from the cells and performed both mRNA and miRNA array analyses,with use of Affymetrix chips,reagents,and instruments(human genome U133 plus 2.0 and miRNA 2.0 arrays).We assessed changes and their significance and interrelationships with Target Scan,Pathway Studios,and Ingenuity software.RESULTS:Changes in mRNA levels were most numerous and striking at 6 h after heme treatment but were similar and still numerous at 24 h.After 6 h of heme exposure,the increase in heme oxygenase 1 gene expression was 60-fold by mRNA and 88-fold by quantitative reverse transcription-polymerase chain reaction.We found striking changes,especially up-regulation by heme of nuclear erythroid-2 related factor-mediated oxidative stress responses,protein ubiquitination,glucocorticoid signaling,P53 signaling,and changes in RNAs that regulate intermediary metabolism.Fewer mRNAs were down-regulated by heme,and the fold decreases were less exuberant than were the increases.Notable decreases after 24 h of heme exposure were patatin-like phospholipase domain-containing protein 3(-6.5-fold),neuronal PAS domain protein 2(-1.93-fold),and protoporphyrinogen oxidase(-1.7-fold).CONCLUSION:Heme excess exhibits several toxic effects on liver and kidney,which deserve study in humans and in animal models of the human porphyrias or other disorders.

Daily genetic profiling indicates JAK/STAT signaling promotes early hepatic stellate cell transdifferentiation

AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor. RESULTS: Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR. CONCLUSION: These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.

microRNAs: Fad or future of liver disease

microRNAs (miRs) are small non-coding RNAs that regulate both mRNA and protein expression of target genes, which results in alterations in mRNA stability or translation inhibition. miRs influence at least one third of all human transcripts and are known regulators of various important cellular growth and differentiation factors. miRs have recently emerged as key regulatory molecules in chronic liver disease. This review details recent contributions to the field of miRs that influence liver development and the broad spectrum of disease, from non-alcoholic fatty liver disease to fibrosis/cirrhosis, with particular emphasis on hepatic stellate cells and potential use of miRs as therapeutic tools.

Targeting collagen expression in alcoholic liver disease

Alcoholic liver disease(ALD)is a leading cause of liver disease and liver-related deaths globally,particularly in developed nations.Liver fibrosis is a consequence of ALD and other chronic liver insults,which can progress to cirrhosis and hepatocellular carcinoma if left un-treated.Liver fibrosis is characterized by accumulation of excess extracellular matrix components,including typeⅠcollagen,which disrupts liver microcirculation and leads to injury.To date,there is no therapy for the treatment of liver fibrosis;thus treatments that either prevent the accumulation of typeⅠcollagen or hasten its degradation are desirable.The focus of this review is to examine the regulation of typeⅠcollagen in fibrogenic cells of the liver and to discuss current advances in therapeutics to eliminate excessive collagen deposition.

Nonmuscle myosin Ⅱ regulates migration but not contraction in rat hepatic stellate cells

AIM: To identify and characterize the function of non-mu-scle myosin Ⅱ (NMM Ⅱ) isoforms in primary rat hepatic stellate cells (HSCs).METHODS: Primary HSCs were isolated from male Spra-gue-Dawley rats by pronase/collagenase digestion. Total RNA and protein were harvested from quiescent and culture-activated HSCs. NMM Ⅱ isoform (Ⅱ-A, Ⅱ-B and Ⅱ-C) gene and protein expression were measured by RealTime polymerase chain reaction and Western blot analyses respectively. NMM Ⅱ protein localization was visualized in vitro using immunocytochemical analysis. For in vivo assessment, liver tissue was harvested from bile duct-ligated (BDL) rats and NMM Ⅱisoform expression determined by immunohistochemistry. Using a selective myosin Ⅱ inhibitor and siRNA-mediated knockdown of each isoform, NMM Ⅱ functionality inprimary rat HSCs was determined by contraction and migration assays.RESULTS: NMM Ⅱ-A and Ⅱ-B mRNA expression was increased in culture-activated HSCs (Day 14) with sig-niflicant increases seen in all pairwise comparisons (Ⅱ-A: 12.67 ± 0.99 (quiescent) vs 17.36 ± 0.78 (Day 14), P < 0.05; Ⅱ-B: 4.94 ± 0.62 (quiescent) vs 13.90 ±0.85 (Day 14), P < 0.001). Protein expression exhibited similar expression patterns (Ⅱ-A: 1.87 ± 2.50 (quiescent) vs 58.64 ± 8.76 (Day 14), P < 0.05; Ⅱ-B: 1.17 ± 1.93 (quiescent) vs 103.71 ± 21.73 (Day 14), P < 0.05). No signif icant differences were observed in NMM Ⅱ-C mRNA and protein expression between quiescent and activated HSCs. In culture-activated HSCs, NMM Ⅱ-A and Ⅱ-B merged with F-actin at the cellular periphery and throughout cytoplasm respectively. In vitro stud-ies showed increased expression of NMM Ⅱ-B in HSCs activated by BDL compared to sham-operated animals. There were no apparent increases of NMM Ⅱ-A and Ⅱ-C protein expression in HSCs during hepatic BDL injury. To determine the contribution of NMM Ⅱ-A and Ⅱ-B to migration and contraction, NMM Ⅱ-A and Ⅱ-B expres-sion were downregulated with siRNA. NMM Ⅱ-A and/or Ⅱ-B siRNA inhibited HSC migration by approximately 25% compared to scramble siRNA-treated cells. Conversely, siRNA-mediated NMM Ⅱ-A and Ⅱ-B inhibition had no signif icant effect on HSC contraction; however, contraction was inhibited with the myosin Ⅱ inhibitor, blebbistatin (38.7% ± 1.9%).CONCLUSION: Increased expression of NMM Ⅱ-A and Ⅱ-B regulates HSC migration, while other myosin Ⅱclasses likely modulate contraction, contributing to development and severity of liver f ibrosis.