Self-assembly of a AuNPs/Ti3C2 MXene hydrogel for cascade amplification of microRNA-122 biosensing

A three-dimensional (3D) self-assembled AuNPs/Ti3C2 MXene hydrogel (AuNPs/Ti3C2 MXH) nanocomposite was prepared for the fabrication of a novel microRNA-122 electrochemical biosensor. The 3D hydrogel structure was gelated from two-dimensional MXene nanosheets with the assistance of graphite oxide and ethylenediamine. MXene hydrogels supported the in situ formation of Au nanoparticles (AuNPs) that predominantly exploring the (111) facet, and these AuNPs are utilized as carriers for hairpin DNA (hpDNA) probes, facilitating DNA hybridization. MXene acted as both a reductant and stabilizer, significantly improving the electrochemical signal. In addition, the conjugation of PAMAM dendrimer-encapsulated AuNPs and H-DNA worked as an ideal bridge to connect targets and efficient electrochemical tags, providing a high amplification efficiency for the sensing of microRNA-122. A linear relationship between the peak currents and the logarithm of the concentrations of microRNA-122 from 1.0 × 10-2 to 1.0 × 102 fM (I = 1.642 + 0.312 lgc, R2 = 0.9891), is obtained. The detection limit is  0.8 × 10-2 fM (S/N = 3). The average recovery for human serum detection ranged from 97.32 to 101.4% (RSD < 5%).

MiRNA-122-5p inhibitor abolishes angiotensin II-mediated loss of autophagy and promotion of apoptosis in rat cardiofibroblasts by modulation of the apelin-AMPK-mTOR signaling

MicroRNAs (miRNAs) have emerged as essential regulators that could have pivotal roles in cardiac homeostasis and pathological remodeling of various cardiovascular diseases. We previously demonstrated that miRNA-122-5p overexpression exacerbated the process of vascular hypertrophy, fibrosis, and dysfunction in hypertensive rats and rat aortic adventitial fibroblasts. However, the exact roles and underlying mechanisms of miRNA-122-5p in myocardial fibroblasts remain largely unknown. In this work, neonatal rat cardiofibroblasts (CFs) were isolated and primarily cultured from the hearts of 2- to 3-d-old Sprague-Dawley rats. Stimulation of angiotensin II (Ang II) resulted in marked increases in cellular proliferation and migration and levels of collagen I, collagen III, CTGF, and TGF-β1 in cultured CFs. Furthermore, Ang II led to promoted expression of P62, Bax, and phosphorylated mTOR as well as downregulation of LC3II, beclin-1, and AMPK-phosphorylated levels, thereby contributing to imbalance of autophagy and apoptosis, and cellular injury in CFs, which were significantly ameliorated by treatment with miRNA-122-5p inhibitor. These changes were associated with decreased levels of collagen I, collagen III, CTGF, and TGF-β1. Furthermore, Ang II-induced loss of autophagy and promotion of apoptosis in CFs were prevented by the treatment with Pyr¹-apelin-13 or AMPK agonist AICAR or mTOR inhibitor rapamycin, respectively. In contrast, administration of miRNA-122-5p mimics and autophagy inhibitor 3-methylademine reversed beneficial roles of Pyr¹-apelin-13. Collectively, these data indicated that miRNA-122-5p is an essential regulator of autophagy and apoptosis in rat CFs via the apelin/AMPK/mTOR signaling pathway, which may be potentially used as a therapeutic target in myocardial fibrosis and related diseases.

Prognostic value of serum microRNA-122 in hepatocellular carcinoma is dependent on coexisting clinical and laboratory factors

BACKGROUND

There is ongoing search for new noninvasive biomarkers to improve management of patients with hepatocellular carcinoma (HCC). Studies, mostly from the Asian-Pacific region, demonstrated differential expression of liver-specific microRNA-122 (miR-122) in tissue as well as in sera of patients with hepatitis B virus- and hepatitis C virus-induced HCC.

AIM

To evaluate prognostic value of miR-122 in patients with HCC in a European population and determine potential factors related to alteration of miR-122 in sera.

METHODS

Patients with confirmed HCC (n = 91) were included in the study over a two-year period. Patients were characterized according to Child-Pugh score, Barcelona clinic liver cancer (BCLC) staging system, etiology of liver disease, laboratory parameters and overall survival. MiR-122 was measured in sera using TaqMan assay normalized to spiked-in cel-miR-39.

RESULTS

Serum miR-122 quantity was independent of the Child-Pugh score, the BCLC stage or the underlying etiology. Significant positive correlation was found between miR-122 and alanine aminotransferase (P < 0.0001), aspartate aminotransferase (P = 0.0001), alpha-fetoprotein (AFP) (P = 0.0034) and hemoglobin concentration (P = 0.076). Negative correlation was observed between miR-122 level and creatinine concentration (P = 0.0028). AFP, Child-Pugh score and BCLC staging system were associated with survival differences. In overall cohort low miR-122 in sera was only associated with a trend for a better overall survival without reaching statistical significance. Subgroup analysis revealed that low miR-122 was significantly associated with better prognosis in patients with advanced cirrhosis (Child-Pugh class B/C), advanced tumor stage (BCLC B/C/D) and normal AFP (< 7 ng/mL).

CONCLUSION

Our results strongly support the value of miR-122 as potential biomarker of liver injury and probably prognosis. Nevertheless, the value of miR-122 in prediction of prognosis of HCC patients was limited to certain patients’ subgroups. Since circulating miR-122 may be influenced by impaired renal function, AFP and hemoglobin concentration, those factors need to be considered while interpreting miR-122 level.

A luminescent microRNA nanoprobe based on the target-triggered release of an iridium(III)-solvent complex from mesoporous silica nanoparticles

A luminescent microRNA nanoprobe based on the target-triggered Ir(III)-solvent complex release has been fabricated. The complex is initially embedded into mesoporous silica nanoparticles (MSNs), and then is capped by single-stranded (ss) DNA. In the presence of the target microRNA, the ssDNA hybridize with the microRNA forming a rigid DNA/RNA heteroduplexes and leaving the surface of MSN. Thus, the capped Ir(III) solvent complex is released and re-coordinated with histidine (His) to form a new luminescent complex. The luminescence intensity of the nascent complex (with excitation/emission maxima at 340/570 nm) is positively correlated with the concentrations of the target microRNA in the range from 0.05 to 2 nM, and the detection limit of microRNA is estimated as 0.2 pM (S/N = 3). The ability of this nanoprobe to detect microRNA in cell extract further demonstrates its potential in practical application. Graphical abstractSchematic of a luminescent microRNA nanoprobe based on the target-triggered release of an Ir(III)-solvent complex from mesoporous silica nanoparticles.

MicroRNA-122 promotes endothelial cell apoptosis by targeting XIAP: Therapeutic implication for atherosclerosis

Endothelial cell (EC) apoptosis is fundamental for the pathophysiology of atherosclerosis, in which microRNAs (miRNAs) emerge as critical regulators. miR-122 has been shown to regulate the apoptosis of various cell types, however, whether miR-122 is associated with atherosclerosis and EC apoptosis remains unknown. In this study, we found that miR-122 expression was increased in the aortic ECs of ApoE^-/- mice fed with a high-fat diet (HFD), as compared to normal-diet (ND), implying a potential association between miR-122 elevation and atherogenesis. In addition, in vitro, miR-122 expression was also induced in human aortic ECs (HAECs) by the treatment of oxidized low-density lipoprotein (ox-LDL), a common atherogenic factor. Functionally, miR-122 knockdown suppressed ox-LDL-induced apoptosis of HAECs, suggesting a pro-apoptotic role of miR-122 in HAECs under this pro-atherogenic condition. Further evidence revealed that the X-linked inhibitor-of-apoptosis protein (XIAP) was directly targeted and suppressed by miR-122 in HAECs, and more importantly, XIAP knockdown diminished miR-122 effect on apoptosis, thus establishing XIAP as a prominent target that mediates miR-122 regulation of the apoptosis of HAECs. Together, these results may identify miR-122 as a novel regulator in EC apoptosis, which offers it as a possible target for therapeutic interventions of atherosclerosis.

Ratiometric Fluorescence Sensor for the MicroRNA Determination by Catalyzed Hairpin Assembly

A novel catalyzed hairpin assembly-based turn-on ratiometric fluorescence biosensor was constructed for the determination of microRNA-122 (miRNA-122) by using 2-aminopurine (2-AP) and thioflavin T (ThT) as detection signal sources. Hairpin DNA sequence (H1) includes the complementary strands of miRNA-122 and G-quadruplex-forming sequence. When miRNA-122 was presented, hybridization occurred between miRNA-122 and part of H1, causing a double-stranded DNA and a G-quadruplex formed. The formed double-stranded DNA significantly decreased the fluorescence intensity of 2-AP. Furthermore, after binding with ThT, the formed G-quadruplex led to the fluorescent enhancement. The hairpin DNA sequence (H2) hybridized with the unfolded H1 and displaced miRNA-122. Finally, the displaced miRNA-122 again hybridized with the H1 and initiated cycle amplification. This sensor showed a linear ranges of 0.5-50 nM and the limit of detection for miRNA-122 assay was 72 pM (with the lowest measured concentration of 500 pM) for determination of miRNA-122 when no other miRNA was present. Measurements on cell lysates from 100, 1000, and 10 000 cells of three different cell lines provided increasing signal ratios, which showed the application potential of the sensor for miRNA determination in real samples.

Leptin reduces microRNA-122 level in hepatic stellate cells in vitro and in vivo

Obese patients, often accompanied by hyperleptinemia, are more likely to develop liver fibrosis. Leptin, an adipocyte-derived hormone, augments inflammatory in liver and promotes hepatic stellate cell (HSC) activation (a key step for liver fibrogenesis) and liver fibrosis. microRNA-122 (miR-122) is the most abundant liver-specific miRNA and can attenuate liver fibrosis. This study examined the effect of leptin on miR-122 level in HSCs in vivo and in vitro. Results demonstrated that leptin reduced the levels of both miR-122 (mature miR-122) and primary miR-122 (pri-miR-122). The effects of leptin on the levels of miR-122 and pri-miR-122 were through at least hedgehog pathway. Leptin-induced decrease in sterol regulatory element-binding protein-1c (SREBP-1c) has been shown to contribute to leptin-induced HSC activation. We revealed a mutual promotional effect between SREBP-1c and miR-122. Further experiments indicated that miR-122 inhibited leptin-induced liver fibrosis in leptin-deficient mouse model. These data have potential implications for clarifying the mechanisms of hepatic fibrogenesis associated with elevated leptin level in human such as obese patients.

HCBP6 Modulates Triglyceride Homeostasis in Hepatocytes Via the SREBP1c/FASN Pathway

Hypertriglyceridemia leads to liver steatosis, cardiovascular disease, and type 2 diabetes. Although HCBP6 (hepatitis C virus core-binding protein 6) was previously shown to be an HCV (hepatitis C virus) core-binding protein, its biological function remains unclear. Here, we demonstrate that HCBP6 negatively regulates intracellular triglyceride (TG) levels in hepatocytes. We found that bidirectional manipulation of hepatocyte HCBP6 expression by knockdown or overexpression results in increased or decreased TG accumulation, respectively. In addition, HCBP6 mRNA and protein levels exhibited significant time- and dose-dependent increases in a cellular model of lipid-overload hepatic steatosis. Furthermore, TG levels are regulated by HCBP6-sterol regulatory element binding protein 1c (SREBP1c)-mediated fatty acid synthase (FASN) expression. We also demonstrate that HCBP6 mRNA and protein expression is inhibited by microRNA-122 (miR-122), and miR-122 overexpression elicited more robust translational repression of luciferase activity driven by the full 3'-UTR of HCBP6. Taken together, our results provide new evidence that miR-122-regulated HCBP6 functions as a sensor protein to maintain intrahepatocyte TG levels.

Impact of circulating miR-122 for histological features and hepatocellular carcinoma of nonalcoholic fatty liver disease in Japan. Hepatol Int. 2016;10:647-656. [PMID: 27074850 DOI: 10.1007/s12072-016-9729-2]

BACKGROUND AND AIM

Relationships between circulating microRNA-122 (miR-122) and histological features of nonalcoholic fatty liver disease (NAFLD) are unclear.

METHODS

The impact of serum miR-122 levels for histological features and hepatocellular carcinoma (HCC) was investigated in 305 Japanese patients with histological proven NAFLD. Twenty-three patients were with HCC at the time of diagnosis of NAFLD, and four patients developed HCC during the follow-up. The cross-sectional or longitudinal evaluations were performed to investigate the impact for HCC.

RESULTS

Serum miR-122 levels (calibrated relative to the median levels of patients) partly affected severity of steatosis, ballooning, lobular inflammation, and stage. Multivariate analysis identified HCC and/or histological components of NASH as morphological factors that independently influenced serum miR-122 levels at the diagnosis of NAFLD. There was a strong correlation between serum miR-122 levels and AST, ALT levels. In cross-sectional evaluation, serum miR-122 levels of patients without HCC were significantly higher than those with HCC in patients of stage 3 but not stage 4. In longitudinal evaluation of one patient with follow-up time of 25 years, from the diagnosis of NAFLD until HCC, serum miR-122 levels had already tended to decrease before the progression of fibrosis stage.

CONCLUSIONS

HCC and/or histological components of NASH affected serum miR-122 levels, independently. In longitudinal evaluation of HCC patients, serum miR-122 levels had already tended to decrease before the progression of fibrosis stage. Further prospective studies are needed to investigate the impact of serum miR-122 for histological features and hepatocarcinogenesis of NAFLD.

Down-regulation of suppressor of cytokine signaling 3 by miR-122 enhances interferon-mediated suppression of hepatitis B virus

MicroRNA-122 (miR-122) is involved in the pathogenesis of several liver diseases, including chronic hepatitis B infection and hepatocellular carcinoma. This study aimed to explore the potential role of miR-122 in the interferon (IFN)-mediated suppression of hepatitis B virus (HBV) in hepatocytes. We found that elevated expression of suppressor of cytokine signaling 3 (SOCS3) following HBV infection, contributed to the inactivation of the IFN signaling pathway. Based on previous studies from our laboratory showing that miR-122 can modulate type I IFN expression by inhibiting SOCS1 expression, we analyzed the SOCS3 mRNA sequence for putative miR-122 binding sites. We demonstrate that miR-122 inhibits SOCS3 expression by targeting the 3'-untranslated region of the SOCS3 mRNA within the region 1887-1910 nucleotides. Finally, we demonstrate that significantly increased levels of IFN lead to decreased HBV expression in miR-122 mimic-treated Huh7 cells, whereas inhibition of endogenous miR-122 leads to enhanced viral production, owing to a marked decrease in IFN expression. Taken together, our results demonstrate that miR-122 down-regulates SOCS3, thus positively affecting the anti-HBV efficiency of endogenous type I IFN. Our study suggests that suppression of miR-122 induced by HBV infection, leads to the inactivation of IFN expression, which in turn enhances HBV replication, contributing to viral persistence and hepatocarcinogenesis.

MicroRNA-122 targets genes related to liver metabolism in chickens

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by targeting mRNAs. MicroRNA-122 (miR-122) has important functions in mammalian and fish livers, but its functions in the poultry liver are largely unknown. In this study, we determined the expression patterns of miR-122 in the chicken and identified its target genes in the chicken liver. We found that chicken miR-122 was highly expressed in the liver and that its expression in the liver was up-regulated during the early posthatch life. By bioinformatics and reporter gene analyses, we identified PKM2, TGFB3, FABP5 and ARCN1 as miR-122 target genes in the chicken liver. miR-122 knockdown in primary chicken hepatocytes and expression analysis of miR-122 and predicted target mRNAs in the chicken liver suggested that the expression of PKM2 and FABP5 in the chicken liver is regulated by miR-122. Knockdown of miR-122 affected the expression of 123 genes in cultured chicken hepatocytes. Among these genes, the largest cluster, which consisted of 21 genes, was involved in liver metabolism. These findings suggest that miR-122 plays a role in liver metabolism in the chicken by directly or indirectly regulating the expression of genes involved in liver metabolism.

Absolute quantification of serum microRNA-122 and its correlation with liver inflammation grade and serum alanine aminotransferase in chronic hepatitis C patients

OBJECTIVES

MicroRNA-122 has been shown to be crucial for efficient HCV RNA replication in vitro. Pretreatment intrahepatic microRNA-122 levels in chronic hepatitis C (CHC) patients have been associated with the outcomes of interferon therapy. Here, we determined microRNA-122 serum levels in CHC patients and healthy donors using an absolute quantification approach and evaluated the correlation with liver inflammation grades and serum alanine aminotransferase (ALT) levels.

METHODS

Serum samples were collected from 105 treatment-naive CHC patients, 11 acute hepatitis patients, and 33 healthy donors. Serum microRNA-122 was measured using the TaqMan RT-qPCR. The cycle threshold values were converted to copy numbers by drawing a standard curve using a chemical synthetic standard. For accurate quantification, copy numbers were further normalized according to the recovery ratios of spiked-in cel-miR-39.

RESULTS

Serum levels of microRNA-122 were significantly higher in acute hepatitis and CHC patients than in healthy donors (p<0.001). However, there was no significant association between microRNA-122 and ALT serum levels or liver inflammation grades.

CONCLUSIONS

The present study showed that serum microRNA-122 was elevated in acute and chronic hepatitis patients. However, this biomarker for acute liver injury did not reflect the liver inflammation activity in CHC patients.

microRNA expression in hepatitis B virus infected primary treeshrew hepatocytes and the independence of intracellular miR-122 level for de novo HBV infection in culture

Infection of Hepatitis B virus (HBV) in hepatocytes has been known to be controlled by multiple cellular factors, while the relationship of the infection and liver microRNAs remains obscure. In this study, a miRNA database, containing 168 unique mature miRNA members from primary hepatocytes of a primate-like animal, northern treeshrew (Tupaia belangeri) that is the only species susceptible for HBV infection other than human and chimpanzee, was established. The relative level of a liver predominant microRNA, miR-122, was markedly increased upon HBV infection of the primary tupaia hepatocyte (PTH). However, introducing neither miR-122 nor its antagonist anti-miR-122 into PTHs, or, HepG2-NTCP that is HepG2 cells with the newly identified receptor sodium taurocholate cotransporting polypeptide (NTCP) did not alter the viral infection on these cells. These data suggest that de novo HBV infection of cultured hepatocytes does not depend on the expression level of intracellular miR-122 of the target cells.

Opportunities and Risks of Host-targeting Antiviral Strategies for Hepatitis C

Hepatitis C virus (HCV) infects more than 2 % of the world population with highest prevalence in parts of Africa and Asia. Past standard of care using interferon α and ribavirin had adverse effects and showed modest efficacy for some HCV genotypes spurring the development of direct acting antivirals (DAAs). Such DAAs target viral proteins and are thus better tolerated but they suffer from emergence of vial resistance. Furthermore, DAAs are often HCV genotype specific. Novel drug candidates targeting host factors required for HCV propagation, so called host-targeting antivirals (HTAs), promise to overcome both caveats. The genetic barrier to resistance is usually considered to be high for HTAs and all HCV genotypes presumably use the same host factors. Recent data, however, challenge these assumptions, at least for some HTAs. Here, we highlight the most important host-targeting strategies against hepatitis C and critically discuss their opportunities and risks.