Over-expression of MiR-122 promotes apoptosis of hepatocellular carcinoma via targeting TLR4

Introduction and objectiveMiR-122 has been regarded as a tumor suppressor. Toll-like receptor 4 (TLR4) has been found to be closely related to metastasis and immune escape of hepatocellular carcinoma (HCC). In the study, we sought to investigate the effect of miR-122 on HCC and the expression of TLR4.Patients or Materials and methodsReal-time PCR and Western blot were performed to detect the expressions of target factors. CCK-8 and flow cytometry analysis were employed to evaluate cell viability and apoptosis, respectively. Luciferase reporter assay was used to determine whether miR-122 could directly regulate the expression of TLR4. Enzyme-linked Immuno Sorbent Assay was adopted to detect the secretion of inflammatory cytokines.ResultsBoth down-regulation of miR-122 and up-regulation of TLR4 were found to be correlated with low overall survival rate of HCC patients. TLR4 may be a direct target gene of miR-122. Over-expression of miR-122 induced apoptosis and inhibited cell viability of HCC by down-regulating TLR4, enhanced the expression of pro-apoptotic genes and suppressed the expression of anti-apoptotic genes. MiR-122 inhibited expressions and activities of inflammatory cytokines, including vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), cyclooxygenase-2 (Cox-2) and prostaglandin E2 (PGE2) and also reduced the expression of matrix metallopeptidase 9 (MMP-9). Furthermore, activities of phosphatidylinositide 3-kinases (PI3K), Akt and nuclear factor-kappa B (NF-κB) were suppressed by miR-122.ConclusionsDown-regulation of miR-122 facilitated the immune escape of HCC by targeting TLR4, which was related to PI3K/Akt/NF-κB signaling pathways. Our study may provide a possible strategy for the treatment of HCC.     

Adipose may actively delay progression of NAFLD by releasing tumor‐suppressing,anti‐fibrotic miR‐122 into circulation

Nonalcoholic fatty liver disease (NAFLD) is the most common liver pathology. Here we propose tissue‐cooperative, homeostatic model of NAFLD. During early stages of NAFLD the intrahepatic production of miR‐122 falls, while the secretion of miRNA‐containing exosomes by adipose increases. Bloodstream carries exosome to the liver, where their miRNA cargo is released to regulate their intrahepatic targets. When the deterioration of adipose catches up with the failing hepatic parenchyma, the external supply of liver‐supporting miRNAs gradually tapers off, leading to the fibrotic decompensation of the liver and an increase in hepatic carcinogenesis. This model may explain paradoxical observations of the disease‐associated decrease in intrahepatic production of certain miRNAs with an increase in their levels in serum. Infusions of miR‐122 and, possibly, some other miRNAs may be efficient for preventing NAFLD‐associated hepatocellular carcinoma. The best candidates for exosome‐wrapped miRNA producer are adipose tissue‐derived mesenchymal stem cells (MSCs), known for their capacity to shed large amounts of exosomes into the media. Notably, MSC‐derived exosomes with no specific loading are already tested in patients with liver fibrosis. Carrier exosomes may be co‐manufactured along with their cargo. Exosome‐delivered miRNA cocktails may augment functioning of human organs suffering from a variety of chronic diseases.     

In vitro and ex vivo autoradiography of the NK-1 antagonist [³H]-LY686017 in Guinea pig brain

NK-1 receptor antagonists have shown potential for the clinical treatment of chemotherapy-induced nausea and vomiting, depression and alcoholism. In a recent study, we disclosed the potential for the NK-1 antagonist, LY686017, to treat alcoholism in a clinical population. To assess whether this compound could be utilized as a platform for a brain imaging ligand, we evaluated the binding of [³H]-LY686017 to sections of guinea pig in vitro. In these studies, [³H]-LY686017 bound with a distribution and pharmacology consistent with the NK-1 receptor. Using sections through the region of the caudate nucleus, we obtained a K_d of 0.34 nM and a B_max of 31.37 fmoles/mg tissue. Based on its high potency and low nonspecific binding in vitro, we initiated studies to evaluate the radioligand as a tool to measure in vivo receptor occupancy. In initial studies, 25 microCi of [³H]-LY686017 was administered via an indwelling jugular catheter and accumulation of radioactivity in the caudate (NK-1 containing tissue) and cerebellum (low NK-1 expression) were assessed. The ratios of caudate to cerebellum radioactivity were optimal 2 h after radioligand administration so this time point was used for subsequent studies. To assess the pharmacological specificity of the radioactivity accumulation, we administered various doses of Aprepitant, a potent NK-1 antagonists 1 h prior to intravenous administration of [³H]-LY686017. Aprepitant produced a dose-dependent reduction in radioactivity in the caudate with an approximate 70% reduction at 10 mg/kg. To image NK-1 receptors, 100 microCi of [³H]-LY686017 was administered and the brains sectioned for autoradiography. In these studies, a characteristic distribution on NK-1 receptors was observed. Based on these results, LY686017 should serve as a suitable chemical platform for future imaging ligand development.     

MicroRNAs as potential circulating biomarkers of drug-induced liver injury: key current and future issues for translation to humans

Drug-induced liver injury (DILI) is a common form of adverse drug reaction seen within the clinic. Sensitive, specific and non-invasive biomarkers of liver toxicity are required to help diagnose hepatotoxicity and also to identify safety liabilities during drug development. Limitations exist in the current gold standard DILI biomarkers: alanine aminotransferase is not liver-specific and therefore gives rise to false-positive signals. Interest has grown in the potential of microRNAs (miRNAs) as biomarkers of DILI. Some miRNAs display remarkable organ specificity, can be measured sensitively and are stable in a wide range of biofluids. However, little is currently known about the mechanisms through which miRNAs are released from cells. Furthermore, a clinically suitable method to measure miRNAs has not yet been developed. This review aims to highlight the current research surrounding these markers and areas in which further work is required to establish these markers within clinical and pre-clinical settings.     

Association of miR-122, miR-124 miR-126 and miR-143 gene polymorphisms with ischemic stroke in the northern Chinese Han population

Abstract

Objectives: Single nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes can have diverse functional consequence by affecting the processing and target selection of miRNA. Recent evidence indicates that miRNA play important roles in the pathogenesis of atherosclerosis, which is a major cause of ischemic stroke (IS). The aim of this study was to clarify whether genetic variations in four miRNA genes (miR-143 rs4705342, miR-122 rs17669, miR-126 rs4636297, and miR-124 rs531564) contribute to IS susceptibility.

Methods: A case-control study was used to explore miRNA genetic polymorphisms in 567 IS patients and 552 control subjects that were frequency matched by age and gender. We genotyped four SNPs using polymerase chain reaction/ligation detection reaction.

Results: The miR-126 gene rs4636297 polymorphism was associated with decreased small vessel stroke risk (GA vs. GG: odds ratio (OR)?=?0.62, p?=?.015; GA?+?AA vs. GG: OR?=?0.637, p?=?.018; A vs. G: OR?=?0.696, p?=?.033). Using logistic regression analysis, this significant association remained after adjusting for confounding risk factors (adjusted OR?=?0.626, 95% confidence interval (CI)?=?0.426–0.921). However, the three other miRNA (miR-143 rs4705342, miR-122 rs17669, and miR-124 r531564) were not associated with IS risk under allele or genotype, nor in different inheritance models. In addition, there were no significant associations with stroke subtypes for these three miRNA SNPs.

Conclusion: Our study suggests that the miR-126 gene rs4636297 polymorphism may play an important role in the pathogenesis of small vessel occlusive stroke in the northern Chinese Han population.