MicroRNA-19b reduces hepatic stellate cell proliferation by targeting GRB2 in hepatic fibrosis models in vivo and in vitro as part of the inhibitory effect of estradiol

ERRFI1 exacerbates hepatic ischemia reperfusion injury by promoting hepatocyte apoptosis and ferroptosis in a GRB2-dependent manner

BACKGROUND

Programmed cell death is an important mechanism for the development of hepatic ischemia and reperfusion (IR) injury, and multiple novel forms of programmed cell death are involved in the pathological process of hepatic IR. ERRFI1 is involved in the regulation of cell apoptosis in myocardial IR. However, the function of ERRFI1 in hepatic IR injury and its modulation of programmed cell death remain largely unknown.

METHODS

Here, we performed functional and molecular mechanism studies in hepatocyte-specific knockout mice and ERRFI1-silenced hepatocytes to investigate the significance of ERRFI1 in hepatic IR injury. The histological severity of livers, enzyme activities, hepatocyte apoptosis and ferroptosis were determined.

RESULTS

ERRFI1 expression increased in liver tissues from mice with IR injury and hepatocytes under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions. Hepatocyte-specific ERRFI1 knockout alleviated IR-induced liver injury in mice by reducing cell apoptosis and ferroptosis. ERRFI1 knockdown reduced apoptotic and ferroptotic hepatocytes induced by OGD/R. Mechanistically, ERRFI1 interacted with GRB2 to maintain its stability by hindering its proteasomal degradation. Overexpression of GRB2 abrogated the effects of ERRFI1 silencing on hepatocyte apoptosis and ferroptosis.

CONCLUSIONS

Our results revealed that the ERRFI1-GRB2 interaction and GRB2 stability are essential for ERRFI1-regulated hepatic IR injury, indicating that inhibition of ERRFI1 or blockade of the ERRFI1-GRB2 interaction may be potential therapeutic strategies in response to hepatic IR injury.

GRB2 serves as a viable target against skin fibrosis in systemic sclerosis by regulating endothelial cell apoptosis

BACKGROUND

Systemic Sclerosis (SSc) is an autoimmune disease characterized by vascular and immune system dysfunction, along with tissue fibrosis. Our previous study found GRB2 was downregulated by salvianolic acid B, a small molecule drug that attenuated skin fibrosis of SSc.

OBJECTIVES

Here we aim to investigate the role of GRB2 in SSc.

METHODS

The microarray data of SSc skin biopsies in Caucasians were obtained from the Gene Expression Omnibus (GEO) database. The expression of GRB2 was further detected in Chinese SSc and healthy controls. Bleomycin (BLM)-induced skin fibrosis mice were used to explore how GRB2 downregulation affected fibrosis. The apoptosis of EA.hy926 endothelial cells was induced by H2O2 and apoptosis ratio was measured by flow cytometric. Transcriptome and phosphoproteomic analyses were performed to explore the regulated pathway.

RESULTS

The expression of GRB2 was significantly enhanced in SSc patient skin, 1.51-fold in Caucasians and 1.40-fold in Chinese. Double immunofluorescence staining showed the endothelial cells of SSc patient's skin highly expressed GRB2. The in vivo study revealed that GRB2 knockdown alleviated skin fibrosis and apoptosis of endothelial cells in BLM mouse skin. The in vitro study showed that GRB2 downregulation inhibited the apoptosis of EA.hy926 and protected them from H2O2-induced hyperpermeability. Moreover, transcriptome and phosphoproteomic analysis suggested the focal adhesion pathway was enriched in GRB2 siRNA transfected endothelial cells.

CONCLUSIONS

Our results demonstrated GRB2 highly expressed in endothelial cells of SSc skin, and inhibiting GRB2 could effectively attenuate BLM-induced skin fibrosis and endothelial cell apoptosis. GRB2 is expected to be a new therapeutic target for SSc.

Depleted HDAC3 attenuates hyperuricemia-induced renal interstitial fibrosis via miR-19b-3p/SF3B3 axis

Dysfunctional histone deacetylases (HDACs) elicit unrestrained fibrosis and damage to organs. With regard to the link between HDACs and fibrosis, this research is practiced to decipher the concrete mechanism of HDAC3 in hyperuricemia (HN)-induced renal interstitial fibrosis (RIF) from microRNA-19b-3p/splicing factor 3b subunit 3 (miR-19b-3p/SF3B3) axis.The HN model was established on rats to induce RIF by oral administration of adenine and potassium oxalate. HN rats were injected with miR-19b-3p- or HDAC3-related vectors to figure out their effects on RIF through detecting 24-h urine protein, uric acid (UA), blood urea nitrogen (BUN) and serum creatinine (Scr) contents and α-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1) and fibronectin (FN) contents in renal tissues and observing pathological damages and RIF index of renal tissues. HDAC3, miR-19b-3p and SF3B3 expression in renal tissues were tested, along with their interactions.Elevated HDAC3 and SF3B3 and reduced miR-19b-3p were displayed in renal tissues of HN rats. Suppressed HDAC3 or promoted miR-19b-3p relieved HN-induced RIF, as reflected by their inhibitory effects on 24 h urine protein, UA, BUN, Scr, α-SMA, TGF-β1, and FN contents and RIF index and their ameliorated effects on pathological damages of renal tissues. HDAC3 bound to the promoter of miR-19b-3p to regulate SF3B3. MiR-19b-3p depletion abrogated down-regulated HDAC3-induced effects on HN-induced RIF.It is delineated that depressed HDAC3 relives HN-induced RIF through restoring miR-19b-3p and knocking down SF3B3, replenishing the references for RIF curing.

MicroRNA-503 Targets Mothers Against Decapentaplegic Homolog 7 Enhancing Hepatic Stellate Cell Activation and Hepatic Fibrosis

BACKGROUND

The hyper-accumulation of extracellular matrix (ECM) is the leading cause of hepatic fibrosis, and TGF-β-induced activation of hepatic stellate cells (HSCs) is the central event of hepatic fibrosis pathogenesis. The deregulation and dysfunction of miRNAs in hepatic fibrosis have been reported previously.

AIMS

To identify miRNA(s) playing a role in HSC activation and the underlying mechanism.

METHODS

We analyzed online microarray expression datasets from Gene Expression Omnibus (GEO) for differentially expressed miRNAs in hepatic fibrosis-related disease liver tissues, examined the specific effects of the candidate miRNA on TGF-β-induced HSC activation, and screened for the targets of the candidate miRNA in the TGF-β/SMAD signaling. Then, the predicted miRNA-mRNA binding, the specific effects of the target mRNA, and the dynamic effects of miRNA and mRNA on TGF-β-induced HSC activation were investigated.

RESULTS

The miR-503 expression was upregulated in TGF-β-activated HSCs. miR-503 overexpression enhanced, while miR-503 inhibition attenuated TGF-β-induced HSC proliferation and ECM accumulation in HSCs. miR-503 targeted SMAD7 to inhibit SMAD7 expression. SMAD7 knockdown also aggravated TGF-β-induced HSC proliferation and ECM accumulation in HSCs. The effects of miR-503 overexpression on TGF-β-induced HSC activation were partially reversed by SMAD7 overexpression. In CCl₄-induced hepatic fibrosis model in rats, miR-503 overexpression aggravated, whereas SMAD7 overexpression improved CCl₄-induced fibrotic changes in rats' liver tissues. The effects of miR-503 overexpression on CCl₄-induced fibrotic changes were partially reversed by SMAD7 overexpression.

CONCLUSION

miR-503 acts on HSC activation and hepatic fibrosis through SMAD7. The miR-503/SMAD7 axis enhances HSC activation and hepatic fibrosis through the TGF-β/SMAD pathway.

Increased expression of GAB1 promotes inflammation and fibrosis in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease mainly characterized by persistent inflammation and fibrosis. The receptor tyrosine kinase (RTK) signal pathway plays an important role in the process of SSc, and Grb2-associated binding protein (GAB) is crucial in activating RTK signalling. A previous study found elevated levels of GAB1 in bleomycin (BLM)-induced fibrotic lungs, but the effects of GAB1 in SSc remain unclear. Our aim was to investigate whether GAB1 was dysregulated and its potential role in SSc. Compared with healthy donors, we found GAB1 expression was 1.6-fold higher in peripheral blood mononuclear cells (PBMC), 2.5-fold higher in CD4 + T cells, and 2-fold higher in skin from of SSc patients (P < .01). At the same time, the levels of type one collagen (COLI) were also significantly increased (1.8-fold higher) in SSc skin. Additionally, BLM-induced SSc mice showed mRNA levels of Gab1 2-fold higher than saline-treated controls, and Gab1 expression correlated positively with collagen content. A further in vitro study showed silencing of GAB1 suppressed inflammatory gene expression in TNF-α induced fibroblasts. Additionally, GAB1 deficiency prominently inhibited cell proliferation and reduced COLI protein levels in TGF-β induced fibroblasts. Taken together, these data suggest that GAB1 has a relatively high expression rate in SSc, and knockdown of GAB1 may attenuate SSc by stimulating inflammatory and fibrotic processes.

Critical role of estrogen in the progression of chronic liver diseases

BACKGROUND

Estrogens regulate sexual function and also have a significant role in various pathophysiological processes. Estrogens have a non-reproductive role as the modulators of the immune system, growth, neuronal function, and metabolism. Estrogen receptors are expressed in the liver and their impaired expression and function are implicated with obesity and liver associated metabolic dysfunctions. The purpose of the current review is to discuss the disparity role of estrogens on several forms of liver diseases.

DATA SOURCES

A comprehensive search in PubMed and EMBASE was conducted using the keywords "estrogens and liver diseases", "estradiol and liver diseases", "hormones and liver diseases", "endocrine function in liver diseases", and "female hormones in liver diseases". Relevant papers published before September 30, 2019 were included.

RESULTS

The present review confirms the imperative role of estrogen in various forms of chronic liver diseases. Estrogens play a key role in maintaining homeostasis and make the liver less susceptible to several forms of chronic liver diseases in healthy premenopausal individuals. In contrast, clinical studies also showed increased estrogen levels with chronic liver diseases.

CONCLUSIONS

Several studies reported the protective role of estrogens in chronic liver diseases and this has been widely accepted and confirmed in experimental studies using ovariectomized rat models. However, in a few clinical studies, increased estrogen levels are also implicated in chronic liver diseases. Therefore, further studies are warranted at molecular level to explore the role of estrogen in various forms of chronic liver diseases.

HMGB1 Inhibits HNF1A to Modulate Liver Fibrogenesis via p65/miR-146b Signaling

High mobility group box 1 (HMGB1) is essential for the pathogenesis of liver injury and liver fibrosis. We previously revealed that miR-146b promotes hepatic stellate cells (HSCs) activation and proliferation. Nevertheless, the potential mechanisms are still unknown. Herein, HMGB1 increased HSCs proliferation and COL1A1 and α-SMA protein levels. However, the knockdown of miR-146b inhibited HSCs proliferation and COL1A1 and α-SMA protein levels induced via HMGB1 treatment. miR-146b was upregulated by HMGB1 and miR-146b targeted hepatocyte nuclear factor 1A (HNF1A) 3'-untranslated region (3'UTR) to modulate its expression negatively. Further, we confirmed that HMGB1 might elicit miR-146b expression via p65 within HSCs. Knockdown or block of HMGB1 relieved the CCl₄-induced liver fibrosis. In fibrotic liver tissues, miR-146b expression was positively correlated with p65 mRNA, but HNF1A mRNA was inversely correlated with p65, and miR-146b expression. In summary, our findings suggest that HMGB1/p65/miR-146b/HNF1A signaling exerts a crucial effect on liver fibrogenesis via the regulation of HSC function.

Identification lncRNA LOC102551149/miR-23a-5p pathway in hepatic fibrosis

BACKGROUND

Hepatic fibrosis is a worldwide incurable disease; due to the complex and unclear mechanism, there lack the effective therapeutic targets. However, the mechanism of miR-23a-5p underling this pathological process is largely not clear. The purpose of this study was to investigate the role of miR-23a-5p in hepatic fibrosis and HSC activation.

METHODS

The content of miR-23a-5p in hepatic fibrosis induced by N-nitrosodimethylamine (NDMA) and HSC activation induced by platelet-derived growth factor (PDGF) was detected by qRT-PCR. H&E staining, Masson staining and Shear wave electrography (SWE) were used to detect the degree of hepatic fibrosis. Immunohistochemistry staining, qRT-PCR and Western blot detect the related markers of liver fibrosis or HSC activation, as well as the related pathway genes and proteins. Dual-luciferase reporter system verifies the interaction between miR-23a-5p with PTEN or miR-23a-5p with lncRNA LOC102551149 in HSC-T6. siRNA and miRNA mimic transfer to HSC-T6 to detect the function of lncRNA LOC102551149 and miR-23a-5p on HSC activation.

RESULTS

After hepatic fibrosis and HSC activation happened, the expression of miR-23a-5p was up-regulated, whereas anti-miR-23a-5p can alleviate hepatic fibrosis and HSC activation. Further research shows miR-23a-5p can target PTEN and degrade it, causing activation of PI3K/Akt/mTOR/Snail pathway. lncRNA LOC102551149 can be used as a competition endogenous RNA (ceRNA) targeting miR-23a-5p through base pairing, and siRNA LOC102551149 or exogenous miR-23a-5p can induce HSC activation through PI3K/Akt/mTOR/Snail pathway.

CONCLUSION

We demonstrate mechanism pathway of miR-23a-5p on hepatic fibrosis and HSC activation, which may develop a therapeutic target for hepatic fibrosis.

Effects of NSUN2 deficiency on the mRNA 5-methylcytosine modification and gene expression profile in HEK293 cells

AIM

To study the biological function of NSUN2 in regulating gene expression and cell proliferation.

MATERIALS & METHODS

The NSUN2 gene was knocked down in HEK293 cells via CRISPR/Cas9 system. mRNA m5C modification and gene expression were assessed using RNA-BisSeq and RNA-Seq.

RESULTS

NSUN2 deficiency could inhibit proliferation and migration of HEK293 cells. A total of 1185 differentially methylated genes and 790 differentially expressed genes were identified. Bioinformatics analysis revealed that the differentially methylated genes were mainly involved in regulating gene expression. Some pathways associated with cell proliferation were significantly enriched by the differentially expressed genes. Additionally, GRB2 and CD44 may be key regulators in NSUN2-mediated cell proliferation.

CONCLUSION

These findings help to elucidate the molecular mechanisms by which NSUN2 affects cell proliferation, migration and other cell phenotypes.

Adiponectin inhibits hepatic stellate cell activation by targeting the PTEN/AKT pathway

Adiponectin inhibits hepatic stellate cell (HSC) activation and subsequent development of liver fibrosis via multiple mechanisms. Phosphatase and tensin homolog deletion 10 (PTEN) plays a crucial role in suppression of HSC activation, but its regulation by adiponectin is not fully understood. Here, we investigated the effect of adiponectin on PTEN in LX-2 cells, a human cell line and examined the underlying molecular mechanisms involved in adiponectin-mediated upregulation of PTEN activity during fibrosis. PTEN expression was found to be significantly reduced in the livers of mice treated with CCl4, whereas its expression was rescued by adiponectin treatment. The DNA methylation proteins DNMT1, DNMT3A, and DNMT3B are all highly expressed in activated primary HSCs compared to quiescent HSCs, and thus represent additional regulatory targets during liver fibrogenesis. Expression of DNMT proteins was significantly induced in the presence of fibrotic stimuli; however, only DNMT3B expression was reduced in the presence of adiponectin. Adiponectin-induced suppression of DNMT3B was found to be mediated by enhanced miR-29b expression. Furthermore, PTEN expression was significantly increased by overexpression of miR-29b, whereas its expression was markedly reduced by a miR-29b inhibitor in LX-2 cells. These findings suggest that adiponectin-induced upregulation of miR-29b can suppress DNMT3B transcription in LX-2 cells, thus resulting in reduced methylation of PTEN CpG islands and ultimately suppressing the PI3K/AKT pathway. Together, these data suggest a possible new explanation for the inhibitory effect of adiponectin on HSC activation and liver fibrogenesis.

MicroRNAs as critical regulators of the endothelial to mesenchymal transition in vascular biology

The endothelial to mesenchymal transition (EndMT) is a newly recognized, fundamental biological process involved in development and tissue regeneration, as well as pathological processes such as the complications of diabetes, fibrosis and pulmonary arterial hypertension. The EndMT process is tightly controlled by diverse signaling networks, similar to the epithelial to mesenchymal transition. Accumulating evidence suggests that microRNAs (miRNAs) are key regulators of this network, with the capacity to target multiple messenger RNAs involved in the EndMT process as well as in the regulation of disease progression. Thus, it is highly important to understand the molecular basis of miRNA control of EndMT. This review highlights the current fund of knowledge regarding the known links between miRNAs and the EndMT process, with a focus on the mechanism that regulates associated signaling pathways and discusses the potential for the EndMT as a therapeutic target to treat many diseases.

miR-93‑mediated collagen expression in stress urinary incontinence via calpain-2

The aim of the present study was to investigate the expression and mechanism of microRNA (miR)‑93 in collagen expression in stress urinary incontinence (SUI). Vaginal tissue, primary fibroblasts and SUI primary fibroblasts were obtained to detect the expression of miR‑93, interstitial collagenase (MMP1), collagen I and calpain‑2. Reverse transcription‑quantitative polymerase chain reaction analysis was performed to detect the levels of miR‑93 and MMP1. Western blotting was used to evaluate the protein levels of calpain‑2, MMP1 and collagen I. MMP1 and hydroxyproline levels in the supernatant were measured by ELISA. The association between miR‑93 and calpain‑2 was investigated by luciferase reporter assays. The expression of miR‑93 and collagen I was significantly downregulated in the SUI group, while the expression of calpain‑2 and MMP1 was significantly upregulated. ELISA analysis demonstrated that the MMP1 level increased and the hydroxyproline level decreased in the SUI group. Additionally, calpain‑2 was identified to be a target of miR‑93, and miR‑93 was able to negatively regulate the expression of calpain‑2. Restoration of calpain‑2 in miR‑93‑overexpresseing SUI primary fibroblasts reversed the alteration in hydroxyproline expression, indicating that calpain‑2 was negatively associated with collagen expression. The results of the present study suggested that miR‑93 regulated MMP1 and collagen I expression in fibroblasts via calpain‑2. miR‑93 mediated collagen expression in stress urinary incontinence via calpain‑2.

Role of growth factor receptor-bound 2 in CCl4-induced hepatic fibrosis

BACKGROUND

Growth Factor Receptor-bound 2 (GRB2) plays a crucial role in regulation of cellular function including proliferation and differentiation, and we previously identified GRB2 as promoting HSCs (HSCs) proliferation. However, the underlying mechanisms that are involving in the regulation of GRB2 in hepatic fibrogenesis remain unknown.

METHODS

In the present study, we tested the function of GRB2 in hepatic fibrosis. Hepatic fibrosis was induced by subcutaneous CCl₄ administration at a dose of 3mL/kg in rats. The rat HSC cell line HSC-T6 were cultured for proliferation investigation by CCK-8 and BrdU incorporation method. The levels of GRB2, HMGB1, PI3K/AKT, COL1A1 and α-SMA were analyzed by western blot or real-time PCR.

RESULTS

showed that the expression of GRB2 and HMGB1 was obviously increased in liver tissues of hepatic fibrosis rats accompanied by up-regulation of COL1A1 and α-SMA. In cultured HSCs, application of exogenous HMGB1 induced cell proliferation and cell proliferation rate concomitantly with up-regulation of GRB2 expression and PI3K/AKT phosphorylation. The effects of HMGB1-induced proliferation of HSCs and up-regulation of COL1A1 and α-SMA were abolished by GRB2 siRNA. HMGB1-induced proliferation of HSCs and up-regulation of COL1A1 and α-SMA was reversed in the presence of LY294002, an inhibitor of PI3K inhibitor.

CONCLUSIONS

These findings suggest that GRB2 plays an important role in CCl₄-induced hepatic fibrosis by regulating HSCs' function, and up-regulation of GRB2 induced by HMGB1 is mediated via the PI3K/AKT pathway.

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.

MicroRNA-19b-3p regulates nasopharyngeal carcinoma radiosensitivity by targeting TNFAIP3/NF-κB axis

Background

Nasopharyngeal carcinoma (NPC) is among the most common squamous cell carcinoma in South China and Southeast Asia. Radiotherapy is the primary treatment for NPC. However, radioresistance acts as a significant factor that limits the efficacy of radiotherapy for NPC patients. Growing evidence supports that microRNAs (miRNAs) play an important role in radiation response.

Methods

Real-time quantitative PCR was used to analyze the expression of miR-19b-3p in NPC cell lines and NP69. miR-19b-3p expression profiles in NPC tissues were obtained from the Gene Expression Omnibus database. The effect of miR-19b-3p on radiosensitivity was evaluated by cell viability assays, colony formation assays and in vivo experiment. Apoptosis and cell cycle were examined by flow cytometry. Luciferase reporter assay was used to assess the target genes of miR-19b-3p. Expression of target proteins and downstream molecules were analyzed by Western blot.

Results

miR-19b-3p was upregulated in NPC and served as an independent predictor for reduced patient survival. Radioresponse assays showed that miR-19b-3p overexpression resulted in decreased sensitivity to irradiation, whereas miR-19b-3p downregulation resulted in increased sensitivity to irradiation in vitro. Moreover, miR-19b-3p decreased the sensitivity of NPC cells to irradiation in vivo. Luciferase reporter assay confirmed that TNFAIP3 was a direct target gene of miR-19b-3p. Knockdown of TNFAIP3 reduced sensitivity to irradiation, whereas upregulation of TNFAIP3 expression reversed the inhibitory effects of miR-19b-3p on NPC cell radiosensitivity. Mechanistically, we found that miR-19b-3p increased NPC cell radioresistance by activating the TNFAIP3/ NF-κB axis.

Conclusions

miR-19b-3p contributes to the radioresistance of NPC by activating the TNFAIP3/ NF-κB axis. miR-19b-3p is a determinant of NPC radioresponse and may serve as a potential therapeutic target in NPC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0465-1) contains supplementary material, which is available to authorized users.

MicroRNA-146a-5p Negatively Regulates Pro-Inflammatory Cytokine Secretion and Cell Activation in Lipopolysaccharide Stimulated Human Hepatic Stellate Cells through Inhibition of Toll-Like Receptor 4 Signaling Pathways

Lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway is demonstrated to be involved in the hepatic fibrosis. MicroRNA (miR)-146a-5p is a key regulator of the innate immune response. The functional significance of miR-146a-5p during the LPS/TLR4 mediated hepatic fibrosis process remains unclear. In this study, we found that TLR4 and α-smooth muscle actin (α-SMA) were up-regulated and miR-146a-5p was down-regulated in human hepatic stellate cell (HSC) line LX2 after LPS stimulation. Overexpression of miR-146a-5p inhibited LPS induced pro-inflammatory cytokines secretion through down-regulating the expression levels of TLR-4, IL-1 receptor-associated kinase 1 (IRAK1), TNF receptor associated factor-6 (TRAF6) and phosphorylation of nuclear factor-kappa B (NF-κB). Knockdown of IRAK1 and TRAF6 also suppressed pro-inflammatory cytokine production by inhibiting NF-κB phosphorylation. In addition, miR-146a-5p mimic blocked LPS induced TRAF6 dependent c-Jun N-terminal kinase (JNK) and Smad2 activation as well as α-SMA production. Taken together, these results suggest that miR-146a-5p suppresses pro-inflammatory cytokine secretion and cell activation of HSC through inhibition of TLR4/NF-κB and TLR4/TRAF6/JNK pathway.

miR-19b controls cardiac fibroblast proliferation and migration

Cardiac fibrosis is a fundamental constituent of a variety of cardiac dysfunction, making it a leading cause of death worldwide. However, no effective treatment for cardiac fibrosis is available. Therefore, novel therapeutics for cardiac fibrosis are highly needed. Recently, miR‐19b has been found to be able to protect hydrogen peroxide (H₂O₂)‐induced apoptosis and improve cell survival in H9C2 cardiomyocytes, while down‐regulation of miR‐19b had opposite effects, indicating that increasing miR‐19b may be a new therapeutic strategy for attenuating cellular apoptosis during myocardial ischaemia–reperfusion injury. However, considering the fact that microRNAs might exert a cell‐specific role, it is highly interesting to determine the role of miR‐19b in cardiac fibroblasts. Here, we found that miR‐19b was able to promote cardiac fibroblast proliferation and migration. However, miR‐19b mimics and inhibitors did not modulate the expression level of collagen I. Pten was identified as a target gene of miR‐19b, which was responsible for the effect of miR‐19b in controlling cardiac fibroblast proliferation and migration. Our data suggest that the role of miR‐19b is cell specific, and systemic miR‐19b targeting in cardiac remodelling might be problematic. Therefore, it is highly needed and also urgent to investigate the role of miR‐19b in cardiac remodelling in vivo.

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.

Low Expression of Mir-137 Predicts Poor Prognosis in Cutaneous Melanoma Patients

BACKGROUND

The present study aimed to measure miR-137 expression in patients with cutaneous melanoma (CM) and to estimate the correlation of miR-137 expression and the prognosis of CM patients.

MATERIAL/METHODS

The expression level of miR-137 was assayed by quantitative real-time PCR (qRT-PCR) and presented as mean ±SD. Chi-square was used to evaluate the relationship between miR-137 expression and clinical characteristics. We used a Kaplan-Meier survival curve to determine the overall survival rate of CM patients. Moreover, the correlation between miR-137 expression and the prognosis of CM patients was confirmed by Cox regression analysis.

RESULTS

The relative expression of miR-137 in CM tissue was 1.59±0.43, while that in paired normal tissue was 2.41±0.54, which was significantly higher. Chi-square analysis showed statistical significance between miR-137 expression and clinical characteristics such as TNM stage, ulcer, and occurrence site (P<0.05). However, no association was found between miR-137 expression and age, sex, or family history (P>0.05). According to the survival curve outcome, patients with low miR-137 expression showed relatively higher mortality (P=0.000) and multivariate analysis verified that low expression of miR-137 predicted poor prognosis of CM patients (HR=8.531, 95% CI=2.950-24.668, P=0.000).

CONCLUSIONS

Compared with paired normal tissues, miR-137 expression was lower in CM tissues. Patients with low miR-137 expression had higher mortality than those with high miR-137 expression, suggesting that low miR-137 expression indicated poor prognosis for CM patients.