MicroRNA-130a and -130b enhance activation of hepatic stellate cells by suppressing PPARγ expression: A rat fibrosis model study

Identification of AGO2 and PLEC genes polymorphisms in Hu sheep and their relationship with body size traits

The body size traits are major traits in livestock, which intuitively displays the development of the animal's bones and muscles. This study used PCR amplification, Sanger sequencing, KASPar genotyping, and quantitative real-time reverse transcription PCR (qRT-PCR) to analyze the Single-nucleotide polymorphism and expression characteristics of Argonaute RISC catalytic component 2 (AGO2) and Plectin (PLEC) genes in Hu sheep. Two intron mutations were found in Hu sheep, which were AGO2 g.51700 A > C and PLEC g.23157 C > T, respectively. Through association analysis of two mutation sites and body size traits, it was found that AGO2 g.51700 A > C mainly affects the chest and cannon circumference of Hu sheep of while PLEC g.23157 C mainly affects body height and body length. The combined genotypes of AGO2 and PLEC genes with body size traits showed SNPs at the AGO2 g.51700 A > C and PLEC g.23157 C > T loci significantly improved the body size traits of Hu sheep. In addition, the AGO2 gene has the highest expression levels in the heart, rumen, and tail fat, and the PLEC gene is highly expressed in the heart. These two loci can provide new research ideas for improving the body size traits of Hu sheep.

Biliary fibrosis is an important but neglected pathological feature in hepatobiliary disorders: from molecular mechanisms to clinical implications

Fibrosis resulting from pathological repair secondary to recurrent or persistent tissue damage often leads to organ failure and mortality. Biliary fibrosis is a crucial but easily neglected pathological feature in hepatobiliary disorders, which may promote the development and progression of benign and malignant biliary diseases through pathological healing mechanisms secondary to biliary tract injuries. Elucidating the etiology and pathogenesis of biliary fibrosis is beneficial to the prevention and treatment of biliary diseases. In this review, we emphasized the importance of biliary fibrosis in cholangiopathies and summarized the clinical manifestations, epidemiology, and aberrant cellular composition involving the biliary ductules, cholangiocytes, immune system, fibroblasts, and the microbiome. We also focused on pivotal signaling pathways and offered insights into ongoing clinical trials and proposing a strategic approach for managing biliary fibrosis-related cholangiopathies. This review will offer a comprehensive perspective on biliary fibrosis and provide an important reference for future mechanism research and innovative therapy to prevent or reverse fibrosis.

The role of miR-143/miR-145 in the development, diagnosis, and treatment of diabetes

Objectives

Diabetes mellitus [DM], is a multifaceted metabolic disease, which has become a worldwide threat to human wellness. Over the past decades, an enormous amount of attention has been devoted to understanding how microRNAs [miRNAs], a class of small non-coding RNA regulators of gene expression at the post-transcriptional level, are tied to DM pathology. It has been demonstrated that miRNAs control insulin synthesis, secretion, and activity. This review aims to provide an evaluation of the use of miR-143 and miR-145 as biomarkers for the diagnosis and prognosis of diabetes.

Methods

The use of miR-143 and miR-145 as biomarkers for the diagnosis and prognosis of diabetes has been studied, and research that examined this link was sought after in the literature. In addition, we will discuss the cellular and molecular pathways of insulin secretion regulation by miR-143/145 expression and finally their role in diabetes.

Results

In the current review, we emphasize recent findings on the miR-143/145 expression profiles as novel DM biomarkers in clinical studies and animal models and highlight recent discoveries on the complex regulatory effect and functional role of miR-143/145 expression in DM.

Conclusion

A novel clinical treatment that alters the expression and activity of miR-143/miR-145 may be able to return cells to their natural state of glucose homeostasis, demonstrating the value of using comprehensive miRNA profiles to predict the beginning of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01317-y.

Differential DNA methylation landscape of miRNAs genes in mice liver fibrosis

BACKGROUND

Patients with chronic liver disease were found nearly all to have liver fibrosis, which is characterized by excess accumulation of extracellular matrix (ECM) proteins. While ECM accumulation can prevent liver infection and injury, it can destroy normal liver function and architecture. miRNA's own regulation was involved in DNA methylation change. The purpose of this study is to detect DNA methylation landscape of miRNAs genes in mice liver fibrosis tissues.

METHODS

Male mice (10-12 weeks) were injected CCl4 from abdominal cavity to induced liver fibrosis. 850 K BeadChips were used to examine DNA methylation change in whole genome. The methylation change of 16 CpG dinucleotides located in promoter regions of 4 miRNA genes were detected by bisulfite sequencing polymerase chain reaction (BSP) to verify chip data accuracy, and these 4 miRNA genes' expressions were detected by RT-qPCR methods.

RESULTS

There are 769 differential methylation sites (DMS) in total between fibrotic liver tissue and normal mice liver tissue, which were related with 148 different miRNA genes. Chips array data were confirmed by bisulfite sequencing polymerase chain reaction (R = 0.953; P < 0.01). GO analysis of the target genes of 2 miRNA revealed that protein binding, cytoplasm and chromatin binding activity were commonly enriched; KEGG pathway enrichment analysis displayed that TGF-beta signaling pathway was commonly enriched.

CONCLUSION

The DNA of 148 miRNA genes was found to have methylation change in liver fibrosis tissue. These discoveries in miRNA genes are beneficial to future miRNA function research in liver fibrosis.

d-Allulose Supplementation Prevents Diet-Induced Hepatic Lipid Accumulation via miR-130-Mediated Regulation in C57BL/6 Mice

SCOPE

d-allulose is a low-calorie rare sugar. It has been reported that d-allulose supplementation significantly inhibits diet-induced hepatic fat accumulation. However, the underlying molecular mechanisms remain unclear. This study elucidates the mechanism underlying the suppressive effect of d-allulose on hepatic fat accumulation in terms of miRNA regulation.

METHODS AND RESULTS

Male C57BL/6 mice are divided into three experimental groups-normal diet and distilled water (CC group), high-fat diet (HFD) and distilled water (HC group), and HFD and 5% d-allulose solution (HA group)-and fed the respective diets for 8 weeks. Weight gain is significantly lower in the HA group than that in the HC group, although the caloric intake is the same in both. Histological analysis of liver tissues reveals excessive lipid accumulation in the HC group; this is greatly attenuated in the HA group. Real-time PCR and western blot analyses demonstrate that, compared to the HC group, the HA group exhibits decreased hepatic PPARγ and CD36 expression. Hepatic miR-130 expression levels are higher in the HA group than those in the CC and HC groups.

CONCLUSIONS

These results indicate that miRNA changes associated with PPARγ may underlie the suppression of hepatic lipid accumulation induced by d-allulose intake.

Exploring the Regulatory Role of ncRNA in NAFLD: A Particular Focus on PPARs

Liver diseases are responsible for global mortality and morbidity and are a significant cause of death worldwide. Consequently, the advancement of new liver disease targets is of great interest. Non-coding RNA (ncRNA), such as microRNA (miRNA) and long ncRNA (lncRNA), has been proven to play a significant role in the pathogenesis of virtually all acute and chronic liver disorders. Recent studies demonstrated the medical applications of miRNA in various phases of hepatic pathology. PPARs play a major role in regulating many signaling pathways involved in various metabolic disorders. Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, encompassing a spectrum spanning from mild steatosis to severe non-alcoholic steatohepatitis (NASH). PPARs were found to be one of the major regulators in the progression of NAFLD. There is no recognized treatment for NAFLD, even though numerous clinical trials are now underway. NAFLD is a major risk factor for developing hepatocellular carcinoma (HCC), and its frequency increases as obesity and diabetes become more prevalent. Reprogramming anti-diabetic and anti-obesity drugs is an effective therapy option for NAFLD and NASH. Several studies have also focused on the role of ncRNAs in the pathophysiology of NAFLD. The regulatory effects of these ncRNAs make them a primary target for treatments and as early biomarkers. In this study, the main focus will be to understand the regulation of PPARs through ncRNAs and their role in NAFLD.

Tumor-derived miR-130b-3p induces cancer-associated fibroblast activation by targeting SPIN90 in luminal A breast cancer

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) interact closely with cancer cells to promote tumor development. Downregulation of SPIN90 in CAFs has been reported to facilitate breast cancer progression, but the underlying mechanism has not been elucidated. Here, we demonstrate that miR-130b-3p directly downregulates SPIN90 in stromal fibroblasts, leading to their differentiation into CAFs. As the decrease of SPIN90 in CAFs was shown to be more prominent in estrogen receptor (ER)-positive breast tumors in this study, miR-130b-3p was selected by bioinformatics analysis of data from patients with ER-positive breast cancer. Ectopic expression of miR-130b-3p in fibroblasts accelerated their differentiation to CAFs that promote cancer cell motility; this was associated with SPIN90 downregulation. We also found that miR-130b-3p was generated in luminal A-type cancer cells and activated fibroblasts after being secreted via exosomes from cancer cells. Finally, miR-130b-3p increased in SPIN90-downregulated tumor stroma of luminal A breast cancer patients and MCF7 cell-xenograft model mice. Our data demonstrate that miR-130b-3p is a key modulator that downregulates SPIN90 in breast CAFs. The inverse correlation between miR-130b-3p and SPIN90 in tumor stroma suggests that the miR-130b-3p/SPIN90 axis is clinically significant for CAF activation during breast cancer progression.

Inflammatory-miR-301a circuitry drives mTOR and Stat3-dependent PSC activation in chronic pancreatitis and PanIN

Activated pancreatic stellate cells (PSCs) are the main cells involved in chronic pancreatitis and pancreatic intraepithelial neoplasia lesion (PanIN). Fine-tuning the precise molecular targets in PSC activation might help the development of PSC-specific therapeutic strategies to tackle progression of pancreatic cancer-related fibrosis. miR-301a is a pro-inflammatory microRNA known to be activated by multiple inflammatory factors in the tumor stroma. Here, we show that miR-301a is highly expressed in activated PSCs in mice, sustained tissue fibrosis in caerulein-induced chronic pancreatitis, and accelerated PanIN formation. Genetic ablation of miR-301a reduced pancreatic fibrosis in mouse models with chronic pancreatitis and PanIN. Cell proliferation and activation of PSCs was inhibited by downregulation of miR-301a via two of its targets, Tsc1 and Gadd45g. Moreover, aberrant PSC expression of miR-301a and Gadd45g restricted the interplay between PSCs and pancreatic cancer cells in tumorigenesis. Our findings suggest that miR-301a activates two major cell proliferation pathways, Tsc1/mTOR and Gadd45g/Stat3, in vivo, to facilitate development of inflammatory-induced PanIN and maintenance of PSC activation and desmoplasia in pancreatic cancer.

Turnera diffusa extract attenuates profibrotic, extracellular matrix and mitochondrial markers in activated human hepatic stellate cells (HSC)

INTRODUCTION AND OBJECTIVES

Hepatic fibrosis is characterized by the accumulation of extracellular matrix which includes the accumulation of α-smooth muscle actin (α-SMA), collagen type I (COL1α1), as well as remodeling induced by metalloproteinases and tissue inhibitor of metalloproteinase (TIMPs), where hepatic stellate cells (HSCs) play a central role. In addition, the transcription factor SNAI1 (which participates in epithelial-mesenchymal transition, EMT) and mitofusin 2 (MFN2, a mitochondrial marker) plays an important role in chronic liver disease. Turnera diffusa (TD), a Mexican endemic plant, has been shown to possess antioxidant and hepatoprotective activity in vitro. We treated human HSC (LX2 cells) with a methanolic extract of Turnera diffusa (METD) to evaluate the mechanism involved in its hepatoprotective effect measured as fibrosis modulation, EMT, and mitochondrial markers.

MATERIALS AND METHODS

HSC LX-2 cells were treated with METD (100 and 200ng/mL) alone or combined with TGF-β (10ng/mL) at different time points (24, 48, and 72h). α-SMA, COL1α1, MMP2, TIMP1, SNAI1, and MFN2 mRNAs and protein levels were determined by real-time quantitative PCR and Western Blot analysis.

RESULTS

We found that METD decreases COL1α1-mRNA, α-SMA, and TIMP1 protein expression in LX2 cells treated with and TGF-β. This treatment also decreases MFN2 and TIMP1 protein expression and induces overexpression of MMP2-mRNA.

CONCLUSIONS

Our results suggest that a methanolic extract of Turnera diffusa is associated with an antifibrotic effect by decreasing profibrotic and mitochondrial markers together with the possible induction of apoptosis through SNAI1 expression in activated HSC cells.

Noncoding RNAs Interactions in Hepatic Stellate Cells during Hepatic Fibrosis

Hepatic fibrosis is a reversible wound healing process following liver injury. Although this process is necessary for maintaining liver integrity, severe excessive extracellular matrix accumulation (ECM) could lead to permanent scar formation and destroy the liver structure. The activation of hepatic stellate cells (HSCs) is a key event in hepatic fibrosis. Previous studies show that most antifibrotic therapies focus on the apoptosis of HSCs and the prevention of HSC activation. Noncoding RNAs (ncRNAs) play a substantial role in HSC activation and are likely to be biomarkers or therapeutic targets for the treatment of hepatic fibrosis. This review summarizes and discusses the previously reported ncRNAs, including the microRNAs, long noncoding RNAs, and circular RNAs, highlighting their regulatory roles and interactions in the signaling pathways that regulate HSC activation in hepatic fibrosis.

Maternal fructose intake predisposes rat offspring to metabolic disorders via abnormal hepatic programming

Given that fructose consumption has increased by more than 10-fold in recent decades, it is possible that excess maternal fructose consumption causes harmful effects in the next generation. This study attempted to elucidate the mechanism of the harmful effects of excessive maternal fructose intake from the perspective of offspring liver function. Female rats during gestation and lactation were fed water containing fructose, and their offspring were fed normal water. We attempted to elucidate the mechanism of fructose-induced transgenerational toxicity by conducting a longitudinal study focusing on hepatic programming prior to disease onset. Impaired Insulin resistance and decreased high-density lipoprotein-cholesterol levels were observed at 160 days of age. However, metabolic disorders were not observed in 60-day-old offspring. Microarray analysis of 60-day-old offspring livers showed the reduction of hepatic insulin-like growth factor-1 (Igf1) mRNA expression. This reduction continued until the rats were aged 160 days and attenuated Igf1 signaling. Hepatic microRNA-29 (miR-29a) and miR-130a, which target Igf1 mRNA, were also found to be upregulated. Interestingly, these miRNAs were upregulated in the absence of metabolic disorder. In this study, we found that maternal fructose intake resulted in dysregulated expression of Igf1 and its target miRNAs in the offspring liver, and that these offspring were more likely to develop metabolic disorders. Abnormal hepatic programming induced by an imbalanced maternal nutritional environment is maintained throughout life, implying that it may contribute to metabolic disorders.

Roles of nuclear receptors in hepatic stellate cells

Introduction: Hepatic stellate cells (HSCs) are essential for physiological homeostasis of the liver extracellular matrix (ECM). Excessive transdifferentiation of HSC from a quiescent to an activated phenotype contributes to disrupt this balance and can lead to liver fibrosis. Accumulating evidence has suggested that nuclear receptors (NRs) are involved in the regulation of HSC activation, proliferation, and function. Therefore, these NRs may be therapeutic targets to balance ECM homeostasis and inhibit HSC activation in liver fibrosis.Areas covered: In this review, the authors summarized the recent progress in the understanding of the regulatory role of NRs in HSCs and their potential as drug targets in liver fibrosis.Expert opinion: NRs are still potential therapy targets for inhibiting HSCs activation and liver fibrosis. However, the development of NRs agonists or antagonists to inhibit HSCs requires fully consideration of systemic effects.

Effect of Chronic Western Diets on Non-Alcoholic Fatty Liver of Male Mice Modifying the PPAR-γ Pathway via miR-27b-5p Regulation

Western diets contribute to metabolic diseases. However, the effects of various diets and epigenetic mechanisms are mostly unknown. Here, six week-old C57BL/6J male and female mice were fed with a low-fat diet (LFD), high-fat diet (HFD), and high-fat high-fructose diet (HFD-HF) for 20 weeks. We determined that HFD-HF or HFD mice experienced significant metabolic dysregulation compared to the LFD. HFD-HF and HFD-fed male mice showed significantly increased body weight, liver size, and fasting glucose levels with downregulated PPARγ, SCD1, and FAS protein expression. In contrast, female mice were less affected by HFD and HFD-HF. As miR-27b contains a seed sequence in PPARγ, it was discovered that these changes are accompanied by male-specific upregulation of miR-27b-5p, which is even more pronounced in the HFD-HF group (p < 0.01 vs. LFD) compared to the HFD group (p < 0.05 vs. LFD). Other miR-27 subtypes were increased but not significantly. HFD-HF showed insignificant changes in fibrosis markers when compared to LFD. Interestingly, fat ballooning in hepatocytes was increased in HFD-fed mice compared to HFD-HF fed mice, however, the HFD-HF liver showed an increase in the number of small cells. Here, we concluded that chronic Western diet-composition administered for 20 weeks may surpass the non-alcoholic fatty liver (NAFL) stage but may be at an intermediate stage between fatty liver and fibrosis via miR-27b-5p-induced PPARγ downregulation.

Non-coding RNA crosstalk with nuclear receptors in liver disease

The dysregulation of nuclear receptors (NRs) underlies the pathogenesis of a variety of liver disorders. Non-coding RNAs (ncRNAs) are defined as RNA molecules transcribed from DNA but not translated into proteins. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two types of ncRNAs that have been extensively studied for regulating gene expression during diverse cellular processes. NRs as therapeutic targets in liver disease have been exemplified by the successful application of their pharmacological ligands in clinics. MiRNA-based reagents or drugs are emerging as flagship products in clinical trials. Advancing our understanding of the crosstalk between NRs and ncRNAs is critical to the development of diagnostic and therapeutic strategies. This review summarizes recent findings on the reciprocal regulation between NRs and ncRNAs (mainly on miRNAs and lncRNAs) and their implication in liver pathophysiology, which might be informative to the translational medicine of targeting NRs and ncRNAs in liver disease.

MicroRNA-130a Is Elevated in Thyroid Eye Disease and Increases Lipid Accumulation in Fibroblasts Through the Suppression of AMPK

Purpose

Thyroid eye disease (TED) is a condition that causes the tissue behind the eye to become inflamed and can result in excessive fatty tissue accumulation in the orbit. Two subpopulations of fibroblasts reside in the orbit: those that highly express Thy1 (Thy1+) and those with little or no Thy1 (Thy1–). Thy1– orbital fibroblasts (OFs) are more prone to lipid accumulation than Thy1+ OFs. The purpose of this study was to investigate the mechanisms whereby Thy1– OFs more readily accumulate lipid.

Methods

We screened Thy1+ and Thy1– OFs for differences in microRNA (miRNA) expression. The effects of increasing miR-130a levels in OFs was investigated by measuring lipid accumulation and visualizing lipid deposits. To determine if adenosine monophosphate-activated protein kinase (AMPK) is important for lipid accumulation, we performed small interfering RNA (siRNA)-mediated knockdown of AMPKβ1. We measured AMPK expression and activity using immunoblotting for AMPK and AMPK target proteins.

Results

We determined that miR-130a was upregulated in Thy1– OFs and that miR-130a targets two subunits of AMPK. Increasing miR-130a levels enhanced lipid accumulation and reduced expression of AMPKα and AMPKβ in OFs. Depletion of AMPK also increased lipid accumulation. Activation of AMPK using AICAR attenuated lipid accumulation and increased phosphorylation of acetyl-CoA carboxylase (ACC) in OFs.

Conclusions

These data suggest that when Thy1– OFs accumulate in TED, miR-130a levels increase, leading to a decrease in AMPK activity. Decreased AMPK activity promotes lipid accumulation in TED OFs, leading to excessive fatty tissue accumulation in the orbit.

Bixin attenuates carbon tetrachloride induced oxidative stress, inflammation and fibrosis in kidney by regulating the Nrf2/TLR4/MyD88 and PPAR-γ/TGF-β1/Smad3 pathway

Bixin, an natural carotenoid extracted from the seeds of the Bixa orellana has been shown to possess numerous important pharmacological activities. The present study was aimed to investigate the mechanisms of Bixin on carbon tetrachloride (CCl4)-induced kidney inflammation, fibrosis and oxidative stress in mice. Our results showed that Bixin improved renal damage by decreasing the serum levels of creatinine, urea, uric acid and alleviating kidney fibrosis. Bixin ameliorated CCl4-induced inflammation in kidneys by reducing the levels of TNF-α and IL-1β. Bixin suppressed oxidative stress by decreasing the MDA level and increasing the activation of SOD, CAT and GPx. Furthermore, Bixin increased the levels of PPAR-γ, NQO1, HO-1 and the nuclear translocation of Nrf2 in the kidneys of mice. Bixin supplementation inhibited the activation of TLR4, MyD88, NF-κB, TGF-β and Smad3. Thus, this study demonstrated that Bixin possesses anti-oxidant, anti-inflammatory and anti-fibrosis properties through regulating the Nrf2/TLR4/MyD88 and PPAR-γ/TGF-β1/Smad3 pathways.

Alpha-1 antitrypsin deficient individuals have circulating extracellular vesicles with profibrogenic cargo

Background

Alpha-1 antitrypsin deficiency (AATD)-mediated liver disease is a toxic “gain-of-function” inflammation in the liver associated with intracellular retention of mutant alpha-1 antitrypsin. The clinical presentation of the disease includes fibrosis, cirrhosis and liver failure. However, the pathogenic mechanism of AATD-mediated liver disease is not well understood. Here, we investigated the role of plasma extracellular vesicles (EVs) in progression of AATD-mediated liver disease.

Methods

EVs were isolated from plasma of AATD individuals with liver disease and healthy controls. Their cytokines and miRNA content were examined by multiplex assay and small RNA sequencing. The bioactivity of EVs was assessed by qPCR, western blot analysis and immunofluorescent experiments using human hepatic stellate cells (HSCs) treated with EVs isolated from control or AATD plasma samples.

Results

We have found that AATD individuals have a distinct population of EVs with pathological cytokine and miRNA contents. When HSCs were cultured with AATD plasma derived-EVs, the expression of genes related to the development of fibrosis were significantly amplified compared to those treated with healthy control plasma EVs.

Conclusion

AATD individuals have a distinct population of EVs with abnormal cytokine and miRNA contents and the capacity to activate HSCs and mediate fibrosis. Better understanding of the components which cause liver inflammation and fibrogenesis, leading to further liver injury, has the potential to lead to the development of new treatments or preventive strategies to prevent AATD-mediated liver disease.

Research on promoting liver fibrosis injury by the targeted regulation of miR-202 for HGF to activate HSC

BACKGROUND

Liver fibrosis is the primary cause of liver cirrhosis and hepatocellular carcinoma and leads to considerable morbidity and mortality. Recent studies have shown that microRNAs are associated with fibrotic processes in liver disorders, but the exact role of miR-202 is still unclear, and its related mechanisms are not fully understood.

AIMS

The aim of this research is to analyze the regarded regulation of miR-202 on HGF and its role in the pathological progress of liver fibrosis.

METHODS

In the present study, qRT-PCR was used to detect the expression level of miR-202 in serum of patients with liver fibrosis and to compare its expression in patients with different pathological stages. HGF was predicted to be the target gene of miR-202 by TargetScan and was verified by Dual-luciferase reporter gene assay. qRT-PCR and western blot were used to detect the regulatory effect of mir-202 on the mRNA and protein of HGF; effect of miR-202 on the expression of fibrosis factors α-smooth muscle actin (α-SMA), FSP1, and collagen was detected; effect of miR-202 on liver fibrosis in mice was detected by establishing CCL4-induced mouse model.

RESULTS

We found that the expression level of miR-202 in serum of patients with liver fibrosis was significantly higher than that of healthy people, and increased with the increase of fibrosis; miR-202 inhibited the expression level of mRNA and protein of HGF by combining with the 3'-UTR of HGF; the expression level of miR-202 significantly increased after hepatic stellate cells (HSC) were stimulated by AngII; the overexpression of miR-202 could up-regulate the expression of fibrotic factors α-SMA, FSP1, and collagen I. In addition, miR-202 up-regulated the expression of collagen I and collagen III in liver tissue of mice with liver fibrosis and promoted the progress of liver fibrosis.

CONCLUSIONS

miR-202 could negatively regulate the expression of target gene HGF, activated HSC, and increased the expression levels of various fibrosis factors, and the pathological process of liver fibrosis injury was promoted.

Peroxisome proliferator-activated receptor γ inhibits hepatic stellate cell activation regulated by miR-942 in chronic hepatitis B liver fibrosis

AIMS

Liver fibrosis is a chronic liver disease characterized by hepatic stellate cell (HSC) activation. Peroxisome proliferator-activated receptor gamma (PPARγ) play an important role in HSC activation. This study aimed to investigate the role of PPARγ in the progression of human hepatic fibrosis and the mechanism by which microRNA-942 regulates HSC activation.

METHODS

70 chronic hepatitis B (CHB) patients liver tissues were used to assess PPARγ, α-SMA and miR-942 levels by immunoblot and real-time PCR. Human primary HSCs or LX2 cells were used to perform multiple molecular experiments based on the transfection of small interfering RNA (siRNA) or co-transfection of microRNA inhibitor. Site-directed mutagenesis and luciferase reporter assays were used to identify miR-942 targets. miR-942 expression and localization in hepatic fibrosis and co-localization between α-SMA were determined by fluorescence in situ hybridization (FISH).

KEY FINDINGS

The mRNA expression of PPARγ was decreased in activated HSCs and CHB patients with liver fibrosis, which was negatively correlated with F stage and α-SMA. miR-942 negatively regulates PPARγ expression via targeting the PPARγ 3'UTR. Inhibiting PPARγ promoted TGFβ1 induced HSC activation, and this effect was blocked after inhibiting the miR-942. Moreover, miR-942 was mainly expressed in fibrous septa and negatively correlated with PPARγ in liver fibrosis.

SIGNIFICANCE

PPARγ targeting by miR-942 and decreasing HSC activation in human hepatic fibrosis. Hence, regulating PPARγ may be a promising therapeutic strategy for hepatic fibrosis.

miR-130b is a potent stimulator of hepatic very-low-density lipoprotein assembly and secretion via marked induction of microsomal triglyceride transfer protein

miR-130b is a microRNA whose expression is particularly elevated within adipose tissue and in the circulation in diabetic states. Hepatic miR-130b expression has been linked to hepatocellular carcinoma and changes in lipid metabolism. Here, we investigated the role of miR-130b in hepatic lipid homeostasis and lipoprotein export. We observed that overexpression of miR-130b-3p or -5p in HepG2 cells markedly enhanced the secretion of very-low-density lipoprotein (VLDL) particles, enhanced the secretion of [³H]glycerol metabolically labeled triglyceride (TG), and significantly increased the number or the average size of lipid droplets (LDs), respectively. Overexpression of miR-130b also altered the expression of key genes involved in lipid metabolism and in particular markedly increased both mRNA and protein expression levels of microsomal triglyceride transfer protein (MTP). Conversely, the miR-130b inhibitor decreased mRNA levels of MTP and fatty acid synthase (FAS) in HepG2 cells. However, dual-luciferase reporter assays indicated that MTP is not a direct target of miR-130b-3p. miR-130b overexpression did not alter de novo synthesized TG or the stability and secretion of apolipoprotein B 100. Interestingly, knockdown of phosphatase and tensin homolog (PTEN) blocked the upregulation of MTP mRNA induced by miR-130b. Finally, miR-130b-induced stimulation of VLDL secretion was also observed in a second hepatocyte cell culture model, immortalized human hepatocytes, confirming the effects observed in HepG2 cells. Overall, these data suggest a potential role for miR-130b in promoting hepatic VLDL assembly and secretion mediated by marked stimulation of MTP expression and TG mobilization. Thus miR-130b overexpression corrects the defect in VLDL production in HepG2 cells.

Platyconic Acid A, Platycodi Radix-Derived Saponin, Suppresses TGF-1-induced Activation of Hepatic Stellate Cells via Blocking SMAD and Activating the PPAR Signaling Pathway

Platycodi radix is a widely sold health food worldwide, which contains numerous phytochemicals that are beneficial to health. Previously, we reported that saponin from the roots of Platycodi radix-derived saponin inhibited toxicant-induced liver diseases. Nevertheless, the inhibitory effect of platyconic acid A (PA), the active component of Platycodi radix-derived saponin, on the anti-fibrotic activity involving the SMAD pathway remains unclear. We investigated the inhibitory effects of PA on TGF-β1-induced activation of hepatic stellate cells (HSCs). PA inhibited TGF-β1-enhanced cell proliferation, as well as expression of α-SMA and collagen Iα1 in HSC-T6 cells. PA suppressed TGF-β1-induced smad2/3 phosphorylation and smad binding elements 4 (SBE4) luciferase activity. Reversely, PA restored TGF-β1-reduced expression of smad7 and peroxisome proliferator-activated receptor (PPAR)γ. PA also repressed TGF-β1-induced phosphorylation of Akt and MAPKs. In summary, the results suggest that the inhibitory effect of PA on HSCs occurs through the blocking of SMAD-dependent and SMAD-independent pathways, leading to the suppression of α-SMA and collagen Iα1 expression.

Lycopene inhibits hepatic stellate cell activation and modulates cellular lipid storage and signaling

Hepatic stellate cells are liver-specific perivascular cells, identified as the major source of collagen in liver fibrosis, following their activation and conversion to myofibroblast-like cells. Lycopene is a carotenoid with biological activities and protective effects described in different pathologies, but little is known about its role in liver protection. We evaluated the influence of lycopene on the cell cycle and lipid metabolism and monitored the possible pathways involved in lycopene inhibition of stellate cell activation. Lycopene induced expression of the lipocyte phenotype, with an accumulation of fat droplets in cytoplasm, with high synthesis and turnover of phospholipids and triglycerides. Cell proliferation analysis showed that lycopene reduced the growth of GRX cells. Lycopene induced an arrest in the G0/G1 phase, followed by a decrease of cells in the G2/M phase, regardless of the concentration of lycopene used. Lycopene modulated relevant signaling pathways related to cholesterol metabolism, cellular proliferation, and lipid metabolism. Also, lycopene treatment increased the expression of RXR-α, RXR-β, and PPARγ, important biomarkers of liver regeneration. These results show that lycopene was able to negatively modulate events related to the activation of hepatic stellate cells through mechanisms that involve changes in expression of cellular lipid metabolism factors, and suggest that this compound might provide a novel pharmacological approach for the prevention and treatment of fibrotic liver diseases.

MicroRNA-130a has pro-fibroproliferative potential in hypertrophic scar by targeting CYLD

Hypertrophic scars are dermal fibrosis diseases that protrude from the surface of the skin and irregularly extend to the periphery, seriously affecting the appearance and limb function of the patient. In this study, we found that microRNA-130a (miR-130a) was increased in hypertrophic scar tissues and derived primary fibroblasts, accompanied by up-regulation of collagen1/3 and α-SMA. Inhibition of miR-130a in hypertrophic scars fibroblasts suppressed the expression of collagen1/3 and α-SMA as well as the cell proliferation. Bioinformatics analysis combined with luciferase reporter gene assay results indicated that CYLD was a target gene of miR-130a, and the miR-130a mimic could reduce the level of CYLD. In contrast to miR-130a, the expression of CYLD was downregulated in hypertrophic scars and their derived fibroblasts. Overexpressing CYLD inhibited the expression of collagen 1/3 and α-SMA, slowed cell proliferation, and inhibited Akt activity. As expected, further study showed that the overexpression of CYLD could prevent the pro-fibroproliferative effects of miR-130a. Consistent with the in vitro results, the inhibitor of miR-130a effectively ameliorated excessive collagen deposition in bleomycin-induced skin fibrosis mouse model. Taken together, our results indicate that miR-130a promotes collagen secretion, myofibroblast transformation and cell proliferation by targeting CYLD and enhancing Akt activity. Therefore, the miR-130a/CYLD/Akt pathway may serve as a novel entry point for future skin fibrosis research.

PPAR-γ: Its ligand and its regulation by microRNAs

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptor superfamily. PPARs are categorized into three subtypes, PPARα, β/δ, and γ, encoded by different genes, expressed in diverse tissues and participate in various biological functions and can be activated by their metabolic derivatives in the body or dietary fatty acids. The PPAR-γ also takes parts in the regulation of energy balance, lipoprotein metabolism, insulin sensitivity, oxidative stress, and inflammatory signaling. It has been implicated in the pathology of numerous diseases including obesity, diabetes, atherosclerosis, and cancers. Among various cellular and molecular targets that are able to regulate PPAR-γ and its underlying pathways, microRNAs (miRNAs) appeared as important regulators. Given that the deregulation of these molecules via targeting PPAR-γ could affect initiation and progression of various diseases, identification of miRNAs that affects PPAR-γ could contribute to the better understanding of roles of PPAR-γ in various biological and pathological conditions. Here, we have summarized the function and various ligands of PPAR-γ and have highlighted various miRNAs involved in the regulation of PPAR-γ.

Comprehensive circular RNA expression profiles in a mouse model of nonalcoholic steatohepatitis

Recent studies have revealed that circular RNAs (circRNAs) are involved in the development of various liver diseases. However, the regulatory role of circRNAs in nonalcoholic steatohepatitis (NASH) has not been fully elucidated. In the present study, the circRNA profiles in a NASH mouse model were investigated, and their functions in NASH were predicted using bioinformatics analysis, with the aim of providing novel clues for delineating the mechanisms of action. A NASH mouse model was established by feeding mice with a methionine and choline‑deficient diet. The liver circRNA profile was screened using a circRNA microarray, and the differentially expressed circRNAs were verified by reverse transcription‑quantitative polymerase chain reaction. Subsequently, circRNA‑microRNA (miRNA) interactions were predicted. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to annotate the biological functions of host linear transcripts of circRNA. A total of 450 circRNAs were revealed to be dysregulated, with 298 circRNAs upregulated and 152 circRNAs downregulated in the NASH model mice. circRNA_29981 was identified as a significantly differentially expressed circRNA. The results from the circRNA‑miRNA pathway interaction analysis revealed that circRNA_29981 was a potential regulator of hepatic stellate cell activation. The host linear transcripts were also analyzed, and the top 10 enriched GO entries and KEGG pathways were annotated. These findings suggested that circRNAs may be important regulators of NASH. Taken together, the results of the present study demonstrated that the circRNA profile in NASH may provide potential candidates for future studies aimed at elucidating the pathogenic mechanism(s) involved in the disease.

Hepatic Ago2-mediated RNA silencing controls energy metabolism linked to AMPK activation and obesity-associated pathophysiology

RNA silencing inhibits mRNA translation. While mRNA translation accounts for the majority of cellular energy expenditure, it is unclear if RNA silencing regulates energy homeostasis. Here, we report that hepatic Argonaute 2 (Ago2)-mediated RNA silencing regulates both intrinsic energy production and consumption and disturbs energy metabolism in the pathogenesis of obesity. Ago2 regulates expression of specific miRNAs including miR-802, miR-103/107, and miR-148a/152, causing metabolic disruption, while simultaneously suppressing the expression of genes regulating glucose and lipid metabolism, including Hnf1β, Cav1, and Ampka1. Liver-specific Ago2-deletion enhances mitochondrial oxidation and ATP consumption associated with mRNA translation, which results in AMPK activation, and improves obesity-associated pathophysiology. Notably, hepatic Ago2-deficiency improves glucose metabolism in conditions of insulin receptor antagonist treatment, high-fat diet challenge, and hepatic AMPKα1-deletion. The regulation of energy metabolism by Ago2 provides a novel paradigm in which RNA silencing plays an integral role in determining basal metabolic activity in obesity-associated sequelae.

rSjP40 protein promotes PPARγ expression in LX-2 cells through microRNA-27b

miR-27b is reported to participate in the proliferation and differentiation of hepatic stellate cells (HSCs) and to regulate fat metabolism of rat HSCs by targeting retinoid X receptor α. Our previous study also indicated that the recombinant P40 protein from Schistosoma japonicum (rSjP40) inhibited the activation of HSCs. In this study, we observed the expression of miR-27b in rSjP40-treated LX-2 cells and explored its potential mechanisms. Quantitative real-time PCR showed that rSjP40 inhibits the expression of miR-27b in LX-2 cells. Further results obtained by Western blot and dual-luciferase reporter assay confirmed that miR-27b regulates peroxisome proliferator-activated receptor γ (PPARγ) expression in rSjP40-treated LX-2 cells by targeting the 3'-UTR of PPARγ. 5-AZA-2'-deoxycytidine (5-AZA-dC), which inhibits methylation of HSCs, partially reversed rSjP40-induced down-regulation expression of miR-27b in LX-2 cells. 5-AZA-dC also partially reversed rSjP40-induced up-regulation expression of PPARγ in LX-2 cells. The increased expression of PPARγ in rSjP40-treated LX-2 cells may be partially due to miR-27b methylation. Therefore, our study provides further insight into the mechanism by which rSjP40 inhibits HSC activation and provides a basis for future study of the blocking effect of rSjP40 in liver fibrosis.-Zhu, D., Lyu, L., Shen, P., Wang, J., Chen, J., Sun, X., Chen, L., Zhang, L., Zhou, Q., Duan, Y. rSjP40 protein promotes PPARγ expression in LX-2 cells through microRNA-27b.

Physiological response and microRNA expression profiles in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to acute cold stress

Cold stress has a serious impact on the overwintering survival and yield of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Understanding the physiological and molecular regulation mechanisms of low-temperature adaptation is necessary to help breed new tolerant strains. The semi-lethal low temperature of juvenile GIFT at 96 h was determined as 9.4 °C. We constructed and sequenced two small RNA libraries from head kidney tissues, one for the control (CO) group and one for the 9.4 °C-stressed (LTS) group, and identified 1736 and 1481 known microRNAs (miRNAs), and 164 and 152 novel miRNAs in the CO and LTS libraries, respectively. We verify the expression of nine up-regulated miRNAs and eight down-regulation miRNAs by qRT-PCR, and found their expression patterns were consistent with the sequencing results. We found that cold stress may have produced dysregulation of free radical and lipid metabolism, decreased superoxide dismutase activity, reduced respiratory burst and phagocytic activity of macrophages, increased malondialdehyde content, and adversely affected the physiological adaptation of GIFT, eventually leading to death. This study revealed interactions among miRNAs and signal regulated pathways in GIFT under cold stress that may help to understand the pathways involved in cold resistance.

MIR196A2 rs11614913 C > T polymorphism correlates with an increased risk of hepatopulmonary syndrome in liver cirrhosis: a case-control study in China

OBJECTIVE

This case-control study is designed to explore the relationship between microRNA-196a2 (MIR196A2) rs11614913 C > T polymorphism and the risk of hepatopulmonary syndrome (HPS) in liver cirrhosis.

METHODS

From January 2013 to January 2015, 163 liver cirrhosis patients with HPS (case group), 264 liver cirrhosis patients without HPS (control group), and 195 healthy people (normal group) were selected. A DNA extraction kit was used to extract plasma DNA from peripheral blood. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the allele and genotype frequencies of MIR196A2 C > T polymorphism. Real-time quantitative polymerase chain reaction was adopted to detect the relative expression of MIR196A.

RESULTS

The frequencies of C allele in the case group were higher than those in the control and normal groups (all P < 0.05), whereas no significant difference was found between the control and normal groups, which indicated that MIR196A2 C > T polymorphism was closely associated with an increased risk of HPS in patients with liver cirrhosis. Compared with the normal group, the relative expression of MIR196A in the case group was significantly increased (P < 0.05), but there was no significant difference in the control group (P > 0.05). In the case group, compared with patients carrying the TT genotype, the relative expression of MIR196A of patients carrying the C allele (CT + CC) evidently increased (P < 0.05).

CONCLUSIONS

The MIR196A2 rs11614913 C > T polymorphism may contribute to an increased risk of HPS in liver cirrhosis patients.

Micro-RNA-130a-3p Regulates Gemcitabine Resistance via PPARG in Cholangiocarcinoma

BACKGROUND

The prognosis of cholangiocarcinoma (CCA) is so poor that its chemoresistance needs to be reduced. In this study, we focused on the microRNAs (miRNAs) associated with gemcitabine resistance of CCA and assessed the clinical significance of miRNAs and their target genes.

METHODS

We performed miRNA microarray analysis for two CCA cell lines (CCLP-1 and MzChA-1) and their gemcitabine-resistant (GR) cells. An miR-130a-3p mimic was induced into CCA cells using lipofection, and we used pioglitazone as a peroxisome proliferator-activated receptor-γ (PPARγ) agonist in vitro. The expression of miR-130a-3p was studied in 27 intrahepatic CCA samples after laser capture microdissection (LCM) and by immunohistochemistry from patients who had undergone curative resection from March 2004 to November 2012 at Osaka University Hospital.

RESULTS

miR-130a-3p expression was upregulated in CCLP-1-GRs and MzChA-1-GRs significantly more than in their parental cells. Transfection of the miR-130a-3p mimic into CCA cells increased gemcitabine resistance, and we detected PPARG as a target gene of miR-130a-3p. Furthermore, pioglitazone had a synergistic effect with gemcitabine and alleviated gemcitabine resistance of CCA GR cells. Moreover, clinical examination revealed that for patients who underwent adjuvant gemcitabine therapy, those who were PPARγ positive had significantly longer disease-free survival than those who were PPARγ negative (n = 5 and 11, respectively; p = 0.027).

CONCLUSIONS

Our data suggest that miR-130a-3p was associated with gemcitabine resistance in CCA through PPARG, and there is a possibility that pioglitazone can be used for the treatment of CCA.

Dysregulation of miRNA Expression in Cancer Associated Fibroblasts (CAFs) and Its Consequences on the Tumor Microenvironment

The tumor microenvironment, including cancer-associated fibroblasts (CAF), has developed as an important target for understanding tumor progression, clinical prognosis and treatment responses of cancer. Cancer cells appear to transform normal fibroblasts (NF) into CAFs involving direct cell-cell communication and epigenetic regulations. This review summarizes the current understanding on miR involvement in cancer cell—tumor environment/stroma communication, transformation of NFs into CAFs, their involved targets and signaling pathways in these interactions; and clinical relevance of CAF-related miR expression profiles. There is evidence that miRs have very similar roles in activating hepatic (HSC) and pancreatic stellate cells (PSC) as part of precancerous fibrotic diseases. In summary, deregulated miRs affect various intracellular functional complexes, such as transcriptional factors, extracellular matrix, cytoskeleton, EMT/MET regulation, soluble factors, tyrosine kinase and G-protein signaling, apoptosis and cell cycle & differentiation, but also formation and composition of the extracellular microenvironment. These processes result in the clinical appearance of desmoplasia involving CAFs and fibrosis characterized by deregulated stellate cells. In addition, modulated release of soluble factors can act as (auto)activating feedback loop for transition of NFs into their pathological counterparts. Furthermore, epigenetic communication between CAFs and cancer cells may confer to cancer specific functional readouts and transition of NF. MiR related epigenetic regulation with many similarities should be considered as key factor in development of cancer and fibrosis specific environment.

MiR-130a-3p attenuates activation and induces apoptosis of hepatic stellate cells in nonalcoholic fibrosing steatohepatitis by directly targeting TGFBR1 and TGFBR2

Nonalcoholic fibrosing steatohepatitis is a uniform process that occurs throughout nonalcoholic fatty liver disease (NAFLD). MicroRNAs (miRNAs) have been shown to be involved in the biological processes, but the role and molecular mechanism of miRNAs in NAFLD are not entirely clear. In this study, we observed a significant reduction in the expression of miR-130a-3p in livers of a mouse model with fibrosis induced by a methionine–choline-deficient diet, of NAFLD patients, and in activated hepatic stellate cells (HSCs). A dual-luciferase activity assay confirmed that transforming growth factor-beta receptors (TGFBRs) 1 and 2 were both the target genes of miR-130a-3p. The hepatic expression of TGFBR1 and TGFBR2 was significantly increased. Moreover, the overexpression of miR-130a-3p in HSCs inhibited HSC activation and proliferation, concomitant with the decreased expression of TGFBR1, TGFBR2, Smad2, Smad3, matrix metalloproteinase-2 (MMP-2), MMP-9, type I collagen (Col-1), and Col-4. In addition, the overexpression of miR-130a-3p promoted HSC apoptosis by inducing the expression of caspase-dependent apoptosis genes. Transfection with si-TGFBR1 and si-TGFBR2 revealed effects on HSC function that were consistent with those of miR-130a-3p. TGFBR1 and TGFBR2 rescued the miR-130a-3p-mediated reductions in the mRNA and protein expression levels of Smad2, Smad3, Col-1, and Col-4. In conclusion, our findings suggest that miR-130a-3p might play a critical role in negatively regulating HSC activation and proliferation in the progression of nonalcoholic fibrosing steatohepatitis by directly targeting TGFBR1 and TGFBR2 via the TGF-β/SMAD signaling pathway.

Gestational Exposure to Sidestream (Secondhand) Cigarette Smoke Promotes Transgenerational Epigenetic Transmission of Exacerbated Allergic Asthma and Bronchopulmonary Dysplasia

Embryonic development is highly sensitive to xenobiotic toxicity and in utero exposure to environmental toxins affects physiological responses of the progeny. In the United States, the prevalence of allergic asthma (AA) is inexplicably rising and in utero exposure to cigarette smoke increases the risk of AA and bronchopulmonary dysplasia (BPD) in children and animal models. We reported that gestational exposure to sidestream cigarette smoke (SS), or secondhand smoke, promoted nicotinic acetylcholine receptor-dependent exacerbation of AA and BPD in mice. Recently, perinatal nicotine injections in rats were reported to induce peroxisome proliferator-activated receptor γ-dependent transgenerational transmission of asthma. Herein, we show that first generation and second generation progeny from gestationally SS-exposed mice exhibit exacerbated AA and BPD that is not dependent on the decrease in peroxisome proliferator-activated receptor γ levels. Lungs from these mice show strong eosinophilic infiltration, excessive Th2 polarization, marked airway hyperresponsiveness, alveolar simplification, decreased lung compliance, and decreased lung angiogenesis. At the molecular level, these changes are associated with increased RUNX3 expression, alveolar cell apoptosis, and the antiangiogenic factor GAX, and decreased expression of HIF-1α and proangiogenic factors NF-κB and VEGFR2 in the 7-d first generation and second generation lungs. Moreover, the lungs from these mice exhibit lower levels of microRNA (miR)-130a and increased levels of miR-16 and miR-221. These miRs regulate HIF-1α-regulated apoptotic, angiogenic, and immune pathways. Thus the intergenerational effects of gestational SS involve epigenetic regulation of HIF-1α through specific miRs contributing to increased incidence of AA and BPD in the progenies.

STX12 lncRNA/miR-148a/SMAD5 participate in the regulation of pancreatic stellate cell activation through a mechanism involving competing endogenous RNA

BACKGROUND

With the deepening of research, the roles of LncRNAs play in the fibrotic process have attracted great attention. At the early stage of pancreatic fibrogenesis, to effectively regulate pancreatic stellate cells (PSCs) activation is crucial for the treatment of chronic pancreatic fibrosis.

METHODS

Microarray data on chronic pancreatitis were retrieved from the Gene Expression Omnibus (GEO) repository and analyzed using bioinformatic methods. A diagram of the lncRNA-miRNA-mRNA ceRNA network was constructed. In addition, activated rat PSCs were transfected with a small interfering RNA (siRNA) targeting the syntaxin-12 (STX12) lncRNA. Then, the expression of STX12, miR-148a and miR-130b were examined by RT-PCR. The expression of the interleukin 6 signal transducer (IL6ST), SMAD family member 5 (SMAD5) and alpha smooth muscle actin (α-SMA) proteins were examined by western blot. The expression of α-SMA were examined by immunofluorescence staining.

RESULTS

Based on the results of bioinformatic analysis, a lncRNA-miRNA-mRNA network was established. A number of putative ceRNA pairs regulating the activation of PSCs were identified, including STX12 lncRNA/(miR-148a or miR-130b)/(SMAD5 or IL6ST). The expression of STX12 was downregulated (relative expression level: 0.23 ± 0.01, P < 0.01), while the expression of miR-148a was significantly elevated (relative expression level: 1.54 ± 0.02, p < 0.01), and the expression of miR-130b was markedly reduced (relative expression level: 0.69 ± 0.02, p < 0.01). The expression of SMAD5 was decreased (relative expression level: 0.70 ± 0.04, p < 0.05), whereas the expression of IL6ST displayed no significant change (p = 0.24). Additionally, the expression of α-SMA was dramatically reduced (relative expression level: 0.32 ± 0.04, p < 0.01), and immunofluorescence analysis confirmed that α-SMA expression was decreased in cells.

CONCLUSION

During the PSCs activation in chronic pancreatitis, the existence of ceRNA interactions in pancreatic fibrosis has been demonstrated. Regulation of the STX12/miR-148a/SMAD5 axis may serve as a new gene therapy strategy for the treatment of chronic pancreatitis and reversal of pancreatic fibrosis.

MicroRNAs regulate hepatic fibrosis via TGF-β/Smad pathway

Studies have shown that transforming growth factor-β (TGF-β) is one of the most important factors to promote hepatic fibrosis (HF), and the TGF-β/Smad pathway is a major signaling pathway involved in HF. Abnormal expression of microRNAs (miRNAs) has a key role in the development of HF. In recent years, studies suggest that regulating miRNAs may affect the TGF-β/Smad pathway. This paper discusses the TGF-β/Smad pathway and the related miRNAs that are associated with HF.

MicroRNAs-Dependent Regulation of PPARs in Metabolic Diseases and Cancers

Peroxisome proliferator-activated receptors (PPARs) are a family of ligand-dependent nuclear receptors, which control the transcription of genes involved in energy homeostasis and inflammation and cell proliferation/differentiation. Alterations of PPARs' expression and/or activity are commonly associated with metabolic disorders occurring with obesity, type 2 diabetes, and fatty liver disease, as well as with inflammation and cancer. Emerging evidence now indicates that microRNAs (miRNAs), a family of small noncoding RNAs, which fine-tune gene expression, play a significant role in the pathophysiological mechanisms regulating the expression and activity of PPARs. Herein, the regulation of PPARs by miRNAs is reviewed in the context of metabolic disorders, inflammation, and cancer. The reciprocal control of miRNAs expression by PPARs, as well as the therapeutic potential of modulating PPAR expression/activity by pharmacological compounds targeting miRNA, is also discussed.

Hepatic Stellate Cells and microRNAs in Pathogenesis of Liver Fibrosis

microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by either blocking translation or inducing degradation of target mRNA. miRNAs play essential roles in diverse biological and pathological processes, including development of hepatic fibrosis. Hepatic stellate cells (HSCs) play a central role in development of hepatic fibrosis and there are intricate regulatory effects of miRNAs on their activation, proliferation, collagen production, migration, and apoptosis. There are multiple differentially expressed miRNAs in activated HSCs, and in this review we aim to summarize current data on miRNAs that participate in the development of hepatic fibrosis. Based on this review, miRNAs may serve as biomarkers for diagnosis of liver disease, as well as markers of disease progression. Most importantly, dysregulated miRNAs may potentially be targeted by novel therapies to treat and reverse progression of hepatic fibrosis.