A Y-shape-structured electrochemiluminescence biosensor based on carbon quantum dots and locked nucleic acid probe for microRNA determination with single-base resolution

Since microRNAs (miRNAs) are predictors of tumorigenesis, accurate identification and quantification of miRNAs with highly similar sequences are expected to reflect tumor diagnosis and treatment. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor was constructed for miRNAs determination based on Y-shaped junction structure equipped with locked nucleic acids (LNA), graphene oxide-based nanocomposite to enrich luminophores, and conductive matrix. Specifically, two LNA-modified probes were designed for specific miRNA recognition, that is, a dual-amine functionalized hairpin capture probe and a signal probe. A Y-shaped DNA junction structure was generated on the electrode surface upon miRNA hybridizing across the two branches, so as to enhance the selectivity. Carbon quantum dots-polyethylene imine-graphene oxide (CQDs-PEI-GO) nanocomposites were developed to enrich luminophores CQDs, and thus enhancing the ECL intensity. For indirect signal amplification, an electrochemically activated poly(2-aminoterephthalic acid) (ATA) film decorated with gold nanoparticles was prepared on electrode as an effective matrix to accelerate the electron transfer. The fabricated ECL biosensor achieved sensitive determination of miRNA-222 with a limit-of-detection (LOD) as low as 1.95 fM (S/N = 3). Notably, Y-shaped junction structures equipped with LNA probes endowed ECL biosensor with salient single-base discrimination ability and anti-interference capacity. Overall, the proposed Y-shaped ECL biosensor has considerable promise for clinical biomarker determination.

[Shenbai Jiedu Fang inhibits AOM/DSS-induced colorectal adenoma formation and carcinogenesis in mice via miRNA-22-mediated regulation of the PTEN/PI3K/AKT signaling pathway]

OBJECTIVE

To observe the inhibitory effect of Shenbai Jiedu Fang (SBJDF, a compound recipe of traditional Chinese herbal drugs) on chemically induced carcinogenesis of colorectal adenoma in mice and explore the role of PTEN/PI3K/AKT signaling pathway in mediating this effect.

METHODS

Four-week-old male C57BL/6 mice were randomly divided into control group (n=10), AOM/DSS model group (n=20), low-dose (14 g/kg) SBJDF group (n=10) and high-dose (42 g/kg) SBJDF group (n= 10). In the latter 3 groups, the mice were treated with azoxymethane (AOM) and dextran sodium sulphate (DSS) to induce carcinogenesis of colorectal adenoma. In the two SBJDF treatment groups, SBJDF was administered daily by gavage during the modeling. The survival rate, body weight, general condition of the mice, and intestinal adenoma formation and carcinogenesis were observed. The expressions of proteins associated with the PTEN/PI3K/AKT signaling pathway in the intestinal tissue were detected using immunohistochemistry.

RESULTS

Compared with those in the model group, the mice treated with SBJDF, especially at the high dose, showed a significantly lower incidence of intestinal carcinogenesis and had fewer intestinal tumors with smaller tumor volume. Pathological examination showed the occurrence of adenocarcinoma in the model group, while only low-grade and high-grade neoplasia were found in low-dose SBJDF group; the mice treated with high-dose SBJDF showed mainly normal mucosal tissues in the intestines with only a few lesions of low-grade neoplasia of adenoma. Compared with those in the control group, the mice in the model group had significantly elevated plasma miRNA-222 level (P < 0.05), which was obviously lowered in the two SBJDF groups (P < 0.01). The results of immunohistochemistry revealed that compared with the model group, the two SBJDF groups, especially the high-dose group, had significantly up-regulated expressions of PTEN, P-PTEN and GSK-3β and down-regulated expressions of p-GSK-3 β, PI3K, AKT, P-AKT, β-catenin, c-myc, cyclinD1 and survivin in the intestinal tissues.

CONCLUSION

SBJDF can significantly inhibit colorectal adenoma formation and carcino-genesis in mice possibly through regulating miRNA-222 and affecting PTEN/PI3K/AKT signaling pathway.

LncRNA LSINCT5/miR-222 regulates myocardial ischemia‑reperfusion injury through PI3K/AKT pathway

Cardiovascular diseases rank the top cause of morbidity and mortality worldwide and are usually associated with blood reperfusion after myocardial ischemia/reperfusion injury (MIRI), which often causes severe pathological damages and cardiomyocyte apoptosis. LSINCT5 expression in the plasma of MI patients (n = 53), healthy controls (n = 42) and hypoxia-reoxygenation (HR)-treated cardiomyocyte AC16 cells was examined using qRT-PCR. The effects of LSINCT5 on cell viability and apoptosis were detected by MTT and flow cytometry, respectively. The expression of apoptosis-related proteins Bcl2, Bax and caspase 3 were tested by Western blot. The interaction between LSINCT5 and miR-222 was predicted by bioinformatic analysis. Moreover, changes in viability and apoptosis of AC16 cells co-transfected with siLSINCT5 and miR-222 inhibitor after HR treatment were examined. At last, the expression of proteins in PI3K/AKT pathway, namely PTEN, PI3K and AKT, was examined to analyze the possible pathway participating in LSINCT5-mediated MI/RI. Our study showed that LSINCT5 expression was upregulated in the plasma of MI patients and HR-treated AC16 cells. LSINCT5 overexpression significantly decreased cell viability and apoptosis. Luciferase reporter gene assay and RNA pulldown assay showed that LSINCT5 was a molecular sponge of miR-222. MiR-222 silencing in AC16 cells simulated the phenotypes of MIRI patients and HR-treated cells, indicating that LSINCT5 functions via miR-222 to regulate proliferation and apoptosis of HR-treated AC16 cells. We also showed that proteins of PI3K/AKT signaling pathway were affected in HR-treated AC16 cells, and LSINTC5 knockdown rescued these effects. LncRNA LSINCT5 was upregulated during MI pathogenesis, and LSINCT5 regulated MIRI possibly via a potential LSINCT5/miR-222 axis and PI3K/AKT signaling pathway. Our findings may provide novel evidence for MIRI prevention.

ADAR1p150 Forms a Complex with Dicer to Promote miRNA-222 Activity and Regulate PTEN Expression in CVB3-Induced Viral Myocarditis

Adenosine deaminases acting on RNA (ADAR) are enzymes that regulate RNA metabolism through post-transcriptional mechanisms. ADAR1 is involved in a variety of pathological conditions including inflammation, cancer, and the host defense against viral infections. However, the role of ADAR1p150 in vascular disease remains unclear. In this study, we examined the expression of ADAR1p150 and its role in viral myocarditis (VMC) in a mouse model. VMC mouse cardiomyocytes showed significantly higher expression of ADAR1p150 compared to the control samples. Coimmunoprecipitation verified that ADAR1p150 forms a complex with Dicer in VMC. miRNA-222, which is involved in many cardiac diseases, is highly expressed in cardiomyocytes in VMC. In addition, the expression of miRNA-222 was promoted by ADAR1p150/Dicer. Among the target genes of miRNA-222, the expression of phosphatase-and-tensin (PTEN) protein was significantly reduced in VMC. By using a bioinformatics tool, we found a potential binding site of miRNA-222 on the PTEN gene’s 3′-UTR, suggesting that miRNA-222 might play a regulatory role. In cultured cells, miR-222 suppressed PTEN expression. Our findings suggest that ADAR1p150 plays a key role in complexing with Dicer and promoting the expression of miRNA-222, the latter of which suppresses the expression of the target gene PTEN during VMC. Our work reveals a previously unknown role of ADAR1p150 in gene expression in VMC.