Overexpression Of miR-125b Research Articles

Tanshinone IIA attenuates the stemness of breast cancer cells via targeting the miR-125b/STARD13 axis

BackgroundTanshinone II A is an effective component extracted from Salvia miltiorrhiza and the roles of Tanshinone IIA in regulating the stemness of tumor cells remain unclear. This work aims to explore the roles and underlying mechanisms of Tanshinone IIA in breast cancer stemness.MethodsIn vitro mammary spheroid formation, flow cytometry assay on CD24−/CD44+ sub-population, ALDH activity detection, cell viability assay and western blot analysis, and in vivo tumor-initiating analysis were performed to examine the effects of Tanshinone IIA on the stemness of breast cancer cells. MiRNAs-based transcriptome sequencing and data analysis, online dataset analysis, luciferase reporter assay combined with rescuing experiments were constructed to explore the underlying mechanisms.ResultsTanshinone IIA attenuated the stemness of breast cancer cells, evident by downregulating the expression of stemness markers, hindering the capacity of spheroid formation, decreasing the CD24−/CD44+ sub-population in a concentration-dependent manner and reducing the tumor-initiating ability of breast cancer cells. Additionally, Tanshinone IIA enhanced adriamycin sensitivity and attenuated adriamycin resistance of breast cancer cells. Combined with miRNAs-based transcriptome sequencing assay, it was found that Tanshinone IIA downregulated miR-125b level and upregulated its target gene STARD13 (StAR-related lipid transfer protein 13) level, thus inactivating the miR-125b/STARD13 axis, which had been previously confirmed to promote breast cancer progression. Notably, miR-125b overexpression enhanced the stemness of breast cancer cells, and miR-125b overexpression or STARD13 knockdown impaired the inhibitory effects of Tanshinone IIA on the stemness of breast cancer cells.ConclusionsTanshinone IIA could attenuate the stemness of breast cancer cells via targeting the miR-125b/STARD13 axis.

Anti-miR-135/SPOCK1 axis antagonizes the influence of metabolism on drug response in intestinal/colon tumour organoids

Little is known about the role of microRNAs (miRNAs) in rewiring the metabolism within tumours and adjacent non-tumour bearing normal tissue and their potential in cancer therapy. This study aimed to investigate the relationship between deregulated miRNAs and metabolic components in murine duodenal polyps and non-polyp-derived organoids (mPOs and mNPOs) from a double-mutant ApcMinFbxw7∆G mouse model of intestinal/colorectal cancer (CRC). We analysed the expression of 373 miRNAs and 12 deregulated metabolic genes in mPOs and mNPOs. Our findings revealed miR-135b might target Spock1. Upregulation of SPOCK1 correlated with advanced stages of CRCs. Knockdown of miR-135b decreased the expression level of SPOCK1, glucose consumption and lactic secretion in CRC patient-derived tumours organoids (CRC tPDOs). Increased SPOCK1 induced by miR-135b overexpression promoted the Warburg effect and consequently antitumour effect of 5-fluorouracil. Thus, combination with miR-135b antisense nucleotides may represent a novel strategy to sensitise CRC to the chemo-reagent based treatment.

Placenta-Specific miR-125b Overexpression Leads to Increased Rates of Pregnancy Loss in Mice.

Pregnancy loss (PL) is one of the common complications that women can experience during pregnancy, with an occurrence rate of 1 to 5%. The potential causes of pregnancy loss are unclear, with no effective treatment modalities being available. It has been previously reported that the level of miR-125b was significantly increased in placentas of PL patients. However, the role of miR-125b in the development of PL still remains unknown. In the current study, an miR-125b placenta-specific over-expression model was constructed by lentiviral transfecting zona-free mouse embryos followed by embryo transfer. On gestation day 15, it was observed that the placenta was significantly smaller in the miR-125b placenta-specific overexpression group than the control group. Additionally, the abortion rate of the miR-125b placenta-specific overexpression group was markedly higher than in the control group. The blood vessel diameter was larger in the miR-125b-overexpressing specific placenta. In addition, miR-125b-overexpressing HTR8 and JEG3 cell lines were also generated to analyze the migration and invasion ability of trophoblasts. The results showed that miR-125b overexpression significantly suppressed the migration and invasion ability of HTR8 and JEG3 cells. Overall, our results demonstrated that miR-125b can affect embryo implantation through modulating placenta angiogenesis and trophoblast cell invasion capacity that can lead to PL.

MiR-181b promotes the oncogenesis of renal cell carcinoma by targeting TIMP3

Renal cell carcinoma (RCC) has a poor prognosis due to limited diagnosis and treatment. Thus, it is necessary to find novel prognostic biomarkers and therapeutic targets. The aberrant expression of microRNAs plays an important role in RCC oncogenesis. Tissue inhibitors of metalloproteinase 3 (TIMP3) acts as a downstream target of miR-181b. The aim of this study was to understand the role and molecular mechanism of miR-181b in RCC oncogenesis. The results showed that miR-181b expression was significantly higher in RCC tumour tissues, especially in those with significant invasion or metastasis. miR-181b overexpression promoted proliferation and migration of the RCC cell line 786-O, while miR-181b knockdown had the opposite effect. In addition, miR-181b was inversely correlated with TIMP3 expression in RCC tumour tissues. miR-181b overexpression reduced TIMP3 expression in RCC cell line 786-O or OS-RC-2, while miR-181b knockdown had the inverse effect. Mechanistically, a luciferase reporter assay confirmed the binding sites of miR-181b on the 3’-UTR of TIMP3, confirming the targeting effect of miR-181b on TIMP3. Overall, miR-181b promotes the development and progression of RCC by targeting TIMP3 expression, indicating the potential use of miR-181b in the diagnosis and treatment of RCC.

MiR-146b suppresses LPS-induced M1 macrophage polarization via inhibiting the FGL2-activated NF-κB/MAPK signaling pathway in inflammatory bowel disease

ObjectivesM1 macrophage polarization and phenotype in Inflammatory Bowel Disease (IBD) are common biological responses. MethodHerein, IBD mice models were constructed and macrophages were derived. ResultsIt was discovered that microRNA-146b (miR-146b) was downregulated in IBD mice and Lipopolysaccharide (LPS)-induced macrophages. Moreover, the inhibitory role of overexpressed miR-146b in reducing the inflammation level and blocking M1 macrophage polarization was confirmed. Further investigation indicated that Fibrinogen Like 2 (FGL2) acted as the target gene of miR-146b, and FGL2 mediated activation of NLRP3, NF-κB-p65, and p38-MAPK. More importantly, it was validated that miR-146b could ameliorate inflammatory phenotype and prevent M1 macrophage polarization via inhibiting FGL2 in vitro, and miR-146b overexpression alleviated the intestinal injury of IBD mice in vivo. ConclusionsOverall, it is potential to use miR-146b for the amelioration of IBD.

Exosomes derived from bone marrow mesenchymal stem cells inhibit neuroinflammation after traumatic brain injury.

Exosomes derived from bone marrow mesenchymal stem cells can inhibit neuroinflammation through regulating microglial phenotypes and promoting nerve injury repair. However, the underlying molecular mechanism remains unclear. In this study, we investigated the mechanism by which exosomes derived from bone marrow mesenchymal stem cells inhibit neuroinflammation. Our in vitro co-culture experiments showed that bone marrow mesenchymal stem cells and their exosomes promoted the polarization of activated BV2 microglia to their anti-inflammatory phenotype, inhibited the expression of proinflammatory cytokines, and increased the expression of anti-inflammatory cytokines. Our in vivo experiments showed that tail vein injection of exosomes reduced cell apoptosis in cortical tissue of mouse models of traumatic brain injury, inhibited neuroinflammation, and promoted the transformation of microglia to the anti-inflammatory phenotype. We screened some microRNAs related to neuroinflammation using microRNA sequencing and found that microRNA-181b seemed to be actively involved in the process. Finally, we regulated the expression of miR181b in the brain tissue of mouse models of traumatic brain injury using lentiviral transfection. We found that miR181b overexpression effectively reduced apoptosis and neuroinflamatory response after traumatic brain injury and promoted the transformation of microglia to the anti-inflammatory phenotype. The interleukin 10/STAT3 pathway was activated during this process. These findings suggest that the inhibitory effects of exosomes derived from bone marrow mesenchymal stem cells on neuroinflamation after traumatic brain injury may be realized by the action of miR181b on the interleukin 10/STAT3 pathway.

Long noncoding RNA Gm44593 attenuates oxidative stress from age-related hearing loss by regulating miR-29b/WNK1

ABSTRACT Long noncoding RNA has been reported to play important role in various disease. However, the function of lncRNA in age-related hearing loss still unclear. The aim of our study is to investigate the function and mechanism of lncRNA Gm44593 in AHL. ATP content, JC-1 assay, mitochondrial content, cell death rates and dual-luciferase reporter assay were performed to assess the function of lncRNA Gm44593 in HEI-OC1 cells. The expression of lncRNA Gm44593 was significantly upregulated upon H2O2 and starvation treatment. Overexpression of lncRNA Gm44593 manifestly reduced the cell death rates. The ATP content, mtDNA content and mitochondrial membrane potential were alleviated upon overexpression of lncRNA Gm44593. We also proved that miR-29b is the direct target of lncRNA Gm44593. Overexpression of miR-29b completely restored the effect induced by lncRNA Gm44593. In addition, we provided evidences that WNK1 is the direct target of miR-29b. Our research uncovers a potential role of lncRNA Gm44593 in age-related hearing loss. We provide new insights into potential therapeutic targets for the amelioration of age-related hearing loss.

Hepatic MIR20B promotes nonalcoholic fatty liver disease by suppressing PPARA.

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation and imbalances in lipid metabolism in the liver. Although nuclear receptors (NRs) play a crucial role in hepatic lipid metabolism, the underlying mechanisms of NR regulation in NAFLD remain largely unclear. Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in human NAFLD patients, we revealed that MIR20B specifically targets PPARA. MIR20B mimic and anti-MIR20B were administered to human HepG2 and Huh-7 cells and mouse primary hepatocytes as well as high-fat diet (HFD)- or methionine-deficient diet (MCD)-fed mice to verify the specific function of MIR20B in NAFLD. We tested the inhibition of the therapeutic effect of a PPARα agonist, fenofibrate, by Mir20b and the synergic effect of combination of fenofibrate with anti-Mir20b in NAFLD mouse model. We revealed that MIR20B specifically targets PPARA through miRNA regulatory network analysis of nuclear receptor genes in NAFLD. The expression of MIR20B was upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of MIR20B significantly increased hepatic lipid accumulation and triglyceride levels. Furthermore, MIR20B significantly reduced FA oxidation and mitochondrial biogenesis by targeting PPARA. In Mir20b-introduced mice, the effect of fenofibrate to ameliorate hepatic steatosis was significantly suppressed. Finally, inhibition of Mir20b significantly increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Moreover, combination of fenofibrate and anti-Mir20b exhibited the synergic effect on improvement of NAFLD in MCD-fed mice. Taken together, our results demonstrate that the novel MIR20B targets PPARA, plays a significant role in hepatic lipid metabolism, and present an opportunity for the development of novel therapeutics for NAFLD. This research was funded by Korea Mouse Phenotyping Project (2016M3A9D5A01952411), the National Research Foundation of Korea (NRF) grant funded by the Korea government (2020R1F1A1061267, 2018R1A5A1024340, NRF-2021R1I1A2041463, 2020R1I1A1A01074940, 2016M3C9A394589324), and the Future-leading Project Research Fund (1.210034.01) of UNIST.

MiR-125b downregulates macrophage scavenger receptor type B1 and reverse cholesterol transport

ObjectiveTo determine whether miR-125b regulates cholesterol efflux in vivo and in vitro through the regulation of scavenger receptor type B1 (SR-B1). Approach and resultsWe demonstrated that miR-125b is up-regulated in the human aortas of patients with CAD and is located in macrophages and vascular smooth muscle cells (VSMCs). We identified SCARB1 as a direct target of miR-125b by repressing the activity of the SCARB1 3′-untranslated region reporter construct. Moreover, the overexpression of miR-125b in both human and mouse macrophages as well as VSMCs was found to downregulated the expression of the SCARB1 and the SR-B1 protein levels, thereby impairing α-HDL-mediated macrophage cholesterol efflux in vitro. The in vivo reverse cholesterol transport (RCT) rate from non-cholesterol-loaded macrophages transfected with miR-125b to feces was also found to be decreased when compared with that of control mimic-transfected macrophages. ConclusionsTogether, these results provide evidence that miR-125b downregulates SCARB1 and SR-B1 in both human and mouse macrophages as well as VSMCs, thereby impairing macrophage cholesterol efflux in vitro and the whole macrophage-specific RCT pathway in vivo.

MicroRNA-30b Is Both Necessary and Sufficient for Interleukin-21 Receptor-Mediated Angiogenesis in Experimental Peripheral Arterial Disease.

The interleukin-21 receptor (IL-21R) can be upregulated in endothelial cells (EC) from ischemic muscles in mice following hind-limb ischemia (HLI), an experimental peripheral arterial disease (PAD) model, blocking this ligand–receptor pathway-impaired STAT3 activation, angiogenesis, and perfusion recovery. We sought to identify mRNA and microRNA transcripts that were differentially regulated following HLI, based on the ischemic muscle having intact, or reduced, IL-21/IL21R signaling. In this comparison, 200 mRNAs were differentially expressed but only six microRNA (miR)/miR clusters (and among these only miR-30b) were upregulated in EC isolated from ischemic muscle. Next, myoglobin-overexpressing transgenic (MgTG) C57BL/6 mice examined following HLI and IL-21 overexpression displayed greater angiogenesis, better perfusion recovery, and less tissue necrosis, with increased miR-30b expression. In EC cultured under hypoxia serum starvation, knock-down of miR-30b reduced, while overexpression of miR-30b increased IL-21-mediated EC survival and angiogenesis. In Il21r−/− mice following HLI, miR-30b overexpression vs. control improved perfusion recovery, with a reduction of suppressor of cytokine signaling 3, a miR-30b target and negative regulator of STAT3. Together, miR-30b appears both necessary and sufficient for IL21/IL-21R-mediated angiogenesis and may present a new therapeutic option to treat PAD if the IL21R is not available for activation.

CDK14/β-catenin/TCF4/miR-26b positive feedback regulation modulating pancreatic cancer cell phenotypes in vitro and tumor growth in mice model in vivo.

Chemotherapy and radiotherapy have been reported to be basically ineffective for pancreatic ductal adenocarcinoma patients; thus, gene therapy might provide a novel approach. CDK14, a new oncogenic member of the CDK family involved in the pancreatic cancer cell response to gemcitabine treatment, has been reported to be regulated by microRNAs. In the present study, we aimed to investigate whether miR-26b regulated CDK14 expression to affect the phenotype of pancreatic cancer cells. Overexpression or knockdown of CDK14 or miR-26b was generated in pancreatic cancer cell lines and the function of CDK14 and miR-26b on cell phenotype and the Wnt signaling pathway was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine and transwell assays, as well as a xenograft model and western blotting. The predicted binding site between the 3'-untranslated region of CDK14 and miR-26b, miR-26b promoter and TCF4 was verified by luciferase or chromatin immunoprecipitation assays. CDK14 overexpression inhibited p-GSK3β, whereas it promoted p-LRP6, the nuclear translocation of β-catenin and the transactivation of TCF4 transcription factor, thus promoting pancreatic cancer cell aggressiveness. miR-26b directly targeted CDK14 and inhibited CDK14 expression. In vitro and in vivo, miR-26b overexpression inhibited, and CDK14 overexpression promoted, cancer cell aggressiveness; CDK14 overexpression partially attenuated the miR-26b overexpression effects on cancer cells. The effects of miR-26b overexpression on tumor growth and the Wnt/β-catenin/TCF4 signaling were partially reversed by CDK14 overexpression. TCF4 inhibited the expression of miR-26b by targeting its promoter region. CDK14, β-catenin, TCF4 and miR-26b form a positive feedback regulation for modulating pancreatic cancer cell phenotypes in vitro and tumor growth in vivo.

MiR-31 targets HSD17B14 and FSHR, and miR-20b targets HSD17B14 to affect apoptosis and steroid hormone metabolism of porcine ovarian granulosa cells

Porcine 17-hydroxysteroid dehydrogenase type 14 (HSD17B14) and FSH reporter (FSHR) genes play important roles in the metabolism of steroid hormones and the apoptosis of ovarian granulosa cells (GCs). Our bioinformatics analyses and the dual luciferase reporter assays indicated that porcine miR-20b and miR-31 target the 3′-UTR region of HSD17B14 gene, and miR-31 also targets the 3′-UTR region of FSHR gene. Overexpression of porcine HSD17B14 gene promoted the conversion from estradiol (E2) to estrone (E1) and increased the apoptosis of porcine GCs. Overexpression of miR-20b down-regulated the mRNA and protein expression level of HSD17B14 gene, decreased the concentration of progesterone (P4) and E1, increased E2, as well as reduced apoptosis of GCs. Moreover, overexpression of miR-31 also down-regulated the protein expression level of HSD17B14 gene, decreased the concentration of P4 and E1, and increased E2. However, miR-31 promoted apoptosis of GCs by targeting to the 3′-UTR of porcine FSHR gene. Taken together, we found that both porcine miR-20b and miR-31 target HSD17B14 gene, but miR-31 also targets FSHR gene to regulate the metabolism of steroid hormones and the apoptosis of porcine ovarian GCs. These findings expand the epigenetic regulatory mechanism of porcine miR-31 and miR-20b in ovarian GCs.

MiR-125b enhances doxorubicin-induced cardiotoxicity by suppressing the nucleus-cytoplasmic translocation of YAP via targeting STARD13.

The clinical application of doxorubicin (Dox) is limited due to its cardiotoxicity, while the pathogenesis remains to be fully understood. Recent studies have suggested that microRNA (miRNA) plays an important role in Dox-induced cardiotoxicity. This work aims to investigate the effects of miR-125b in Dox-induced cardiotoxicity. Here, mice model combined with cell line analysis were used, and cell viability assay, detection of reactive oxygen species (ROS), malondialdehyde (MDA) activity, lactate dehydrogenase (LDH) activity, glutathione (GSH) level, glutathione peroxidase (GSH-Px) level, superoxide dismutase (SOD) activity, and histopathological changes were performed to characterize miR-125b effects; real-time quantitative polymerase chain reaction (PCR), luciferase reporter assay, RNA immunoprecipitation, and western blot analysis were subjected to reveal the underlying mechanisms. It was found that miR-125b level was upregulated in myocardial cell line H9C2 treated with Dox and miR-125b overexpression enhanced Dox-induced cytotoxicology of H9C2 cells, while miR-125b inhibition exhibited a protective effect by measuring ROS level and cell viability. In consistent, in vivo experiments with miR-125b agomir or antagomir obtained a consistent result through examining the activity of MDA, LDH, GSH, GSH-Px, SOD, and histopathological changes. Furthermore, we found that miR-125b could target STARD13 and thus suppressed the nucleus-cytoplasmic translocation of yes-associated protein (YAP). Additionally, this STARD13/YAP axis is necessary for miR-125b-mediated regulation on Dox-induced cytotoxicology of H9C2 cells. In conclusion, our study demonstrated that miR-125b could enhance Dox-induced cardiotoxicity through targeting the STARD13/YAP axis.

MicroRNA-193b impairs muscle growth in mouse models of type 2 diabetes by targeting the PDK1/Akt signalling pathway

Aims/hypothesisType 2 diabetes is associated with a reduction in skeletal muscle mass; however, how the progression of sarcopenia is induced and regulated remains largely unknown. We aimed to find out whether a specific microRNA (miR) may contribute to skeletal muscle atrophy in type 2 diabetes.MethodsAdeno-associated virus (AAV)-mediated skeletal muscle miR-193b overexpression in C57BLKS/J mice, and skeletal muscle miR-193b deficiency in db/db mice were used to explore the function of miR-193b in muscle loss. In C57BL/6 J mice, tibialis anterior-specific deletion of 3-phosphoinositide-dependent protein kinase-1 (PDK1), mediated by in situ AAV injection, was used to confirm whether miR-193b regulates muscle growth through PDK1. Serum miR-193b levels were also analysed in healthy individuals (n = 20) and those with type 2 diabetes (n = 20), and correlations of miR-193b levels with HbA1c, fasting blood glucose (FBG), body composition, triacylglycerols and C-peptide were assessed.ResultsIn this study, we found that serum miR-193b levels increased in individuals with type 2 diabetes and negatively correlated with muscle mass in these participants. Functional studies further showed that AAV-mediated overexpression of miR-193b induced muscle loss and dysfunction in healthy mice. In contrast, suppression of miR-193b attenuated muscle loss and dysfunction in db/db mice. Mechanistic analysis revealed that miR-193b could target Pdk1 expression to inactivate the Akt/mammalian target of rapamycin (mTOR)/p70S6 kinase (S6K) pathway, thereby inhibiting protein synthesis. Therefore, knockdown of PDK1 in healthy mice blocked miR-193b-induced inactivation of the Akt/mTOR/S6K pathway and impairment of muscle growth.Conclusions/interpretationOur results identified a previously unrecognised role of miR-193b in muscle function and mass that could be a potential therapeutic target for treating sarcopenia.Graphical abstract

MiR-27b attenuates dexamethasone-inhibited proliferation and osteoblastic differentiation in MC3T3-E1 cells by targeting PPARγ2.

Osteoporosis is a metabolic bone illness characterized by low bone density and a high risk of fracture. It is estimated that there are >60 million individuals in China suffering from this disease, which highlights an urgent requirement for the development of novel and safe drugs for the long-term treatment of osteoporosis. MicroRNAs (miRNAs/miRs) have previously been identified as critical regulators in the progression of osteoporosis. As an intronic miRNA, miR-27b enhances the osteoblastic differentiation of stem cells from the bone marrow and the maxillary sinus membrane. However, the mechanism underlying miR-27b in osteoporosis remains to be elucidated. In the present study, MC3T3-E1 pre-osteoblasts were treated with dexamethasone (DEX) to establish an in vitro model of osteoporosis. The results of the present study demonstrated that DEX treatment markedly inhibited the viability of MC3T3-E1 cells, and downregulated the expression level of miR-27b. The results of reverse transcription-quantitative PCR, western blotting and dual-luciferase assays revealed that miR-27b directly regulated and suppressed the expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) in MC3T3-E1 cells. Furthermore, overexpression of miR-27b by transfection of cells with miR-27b mimic attenuated DEX-mediated inhibition of cell viability, alkaline phosphatase (ALP) activity and the expression levels of bone morphogenetic protein-2 (BMP2), runt-related protein 2 (Runx2) and osteocalcin (OCN). The results of the present study indicated that miR-27b alleviated DEX-inhibited proliferation and osteoblastic differentiation. Moreover, miR-27b knockdown repressed MC3T3-E1 cell viability, ALP activity and protein levels of BMP2, Runx2 and OCN. However, these effects were abrogated by small interfering RNA-mediated PPARγ2 silencing. In conclusion, the results of the present study demonstrated that miR-27b attenuated DEX-inhibited proliferation and osteoblastic differentiation in MC3T3-E1 pre-osteoblasts by targeting PPARγ2.

MiR-125b attenuates retinal pigment epithelium oxidative damage via targeting Nrf2/HIF-1α signal pathway

The retinal pigment epithelium cells (RPE) are sensitive to oxidative stimuli due to long-term exposure to various environmental stimuli. Thus, the oxidative injury of RPE cells caused by the imbalance of redox homeostasis is one of the main pathogenic factors of age-related macular degeneration (AMD). But the sophisticated mechanisms linking AMD to oxidative stress are not fully elucidated. Activation of Nrf2 signal pathway can protect RPE cells from oxidative damage. The present study investigated the regulating mechanism of miR-125b in Nrf2 cascade and evaluated its antioxidant capacity. The in vitro studies indicated that overexpression of miR-125b substantially inhibited Keap1 expression, enhanced Nrf2 expression and induced Nrf2 nuclear translocation. Importantly, functional studies demonstrated that forced expression of miR-125b could significantly elevate cell proliferation and superoxide dismutase (SOD) levels while reduce reactive oxygen species (ROS) overproduction and malondialdehyde (MDA) formation. Further studies showed that miR-125b had no effect when Nrf2 was silenced in ARPE-19 cells. Additionally, the results identified that Nrf2 silence induced ROS accumulation enhances HIF-1α protein expression, while miR-125b could offset this effect via promoting HIF-1α protein degradation. Subsequent in vivo studies demonstrated that sodium iodate induced outer retina thinner was reversed with exogenous supplementation of miR-125b, which was cancelled in Nrf2 knockout mice. In conclusion, this study illustrated that miR-125b can protect RPE from oxidative damage via targeting Nrf2/HIF-1α signal pathway and potentially may serve as a therapeutic agent of AMD.

Overexpression of microRNA-135b-5p attenuates acute myocardial infarction injury through its anti-oxidant and anti-apptotic properties

Abstract Objective Myocardial infarction (MI) remains the leading cause of morbidity and mortality due partly to the limited regenerative capacity of cardiomyocytes to replace cardiomyocyte lost due to apoptosis. Inhibiting cardiomyocyte apoptosis is recognized as an effective therapeutic approach for MI. MicroRNAs (miRNAs, miRs), which regulate target genes at the post-transcriptional level, play a significant role in the regulation of cardiovascular diseases such as MI. MicroRNA-135b (miR-135b) has a protective effect on cardiomyocytes. However, the role of miR-135b in cardiomyocyte apoptosis in infarct myocardium needs further clarification. Methods We generated α-MHC-miR-135b transgenic mice to investigate the role of miR-135b in myocardial injury after MI. MiR-135b mimic and negative control (NC) were transfected into H2O2-induced cardiomyocytes to evaluate the effect of overexpression of miR-135b on the levels of reactive oxygen species (ROS) and apoptosis. Results Our results showed that overexpression of miR-135b had protective effect on cardiomyocyte injury both in vivo and in vitro. MiR-135b inhibited cardiomyocyte apoptosis and ROS generation, downregulated proapoptosis proteins (cleaved-caspase-3 and Bax), and increased anti-apoptosis protein (Bcl-2). Moreover, miR-135b showed an inhibitory effect on apoptosis-related protein target transient receptor potential vanilloid-type 4 (TRPV4) cation channel. Conclusion MiR-135b might be considered a new molecular target for potential replacement therapy as antiapoptotic cardioprotection in the setting of MI.

MicroRNA-106b overexpression suppresses synovial inflammation and alleviates synovial damage in patients with rheumatoid arthritis.

To explore the effect of miR-106b on synovial inflammation and damage in rheumatoid arthritis (RA) patients and further to investigate its possible mechanism. Quantitative real-time polymerase chain reaction, immunofluorescence, in situ hybridization, and immunohistochemistry assay were used to verify the levels of miR-106b and cytokines. Pearson's correlation analysis was conducted to examine bivariate relationship between miR-106b and cytokines or receptor activator of nuclear factor-κ B ligand (RANKL). Following the isolation of fibroblast-like synoviocytes (FLS), the cultured cells were separately transfected with or without miR-106b mimic. Thereafter, cell proliferation, invasion and migration were measured by Cell Counting Kit-8 assay and Transwell assay, respectively. Furthermore, concentration and expression of cytokines were separately detected by enzyme-linked immunosorbent assay and Western blot. Compared with osteoarthritis, RA patients had a lower level of miR-106b and higher levels of RANKL, tumour necrosis factor-a (TNF-a), and interleukin-6 (IL-6). The relative transcription of miR-106b level was negatively correlated to TNF-a, IL-6, and RNKAL levels in both patients (all P < 0.05). Furthermore, miR-106b overexpression suppressed cell proliferation, migration, and invasion capacity of RA-FLS. miR-106b overexpression suppresses synovial inflammation and alleviates synovial damage; thus, it may be served as a potential therapeutic target for RA patients.

Posttranscriptional modulation of KCNQ2 gene expression by the miR-106b microRNA family

MicroRNAs (miRNAs) have recently emerged as important regulators of ion channel expression. We show here that select miR-106b family members repress the expression of the KCNQ2 K+ channel protein by binding to the 3'-untranslated region of KCNQ2 messenger RNA. During the first few weeks after birth, the expression of miR-106b family members rapidly decreases, whereas KCNQ2 protein level inversely increases. Overexpression of miR-106b mimics resulted in a reduction in KCNQ2 protein levels. Conversely, KCNQ2 levels were up-regulated in neurons transfected with antisense miRNA inhibitors. By constructing more specific and stable forms of miR-106b controlling systems, we further confirmed that overexpression of precursor-miR-106b-5p led to a decrease in KCNQ current density and an increase in firing frequency of hippocampal neurons, while tough decoy miR-106b-5p dramatically increased current density and decreased neuronal excitability. These results unmask a regulatory mechanism of KCNQ2 channel expression in early postnatal development and hint at a role for miR-106b up-regulation in the pathophysiology of epilepsy.

MiR-125b Promotes Colorectal Cancer Migration and Invasion by Dual-Targeting CFTR and CGN.

Simple SummaryColorectal cancer (CRC) is the third leading cause for cancer related death, in which metastasis exerts a pivotal role. Therefore, we aim to find out the possible mechanism underlying CRC metastasis. We found that the level of miR-125b was elevated in normal, primary CRC, and distant metastasis tissues stepwise, and high level miR-125b was positively correlated with lymph node metastasis and tumor differentiation. In vitro and in vivo assays showed miR-125b significantly promoted CRC migration and invasion. To elucidate the potential mechanism, cystic fibrosis transmembrane conductance regulator (CFTR) and cingulin (CGN) were defined as two target genes of miR-125b. On the one hand, miR-125b promoted epithelial-mesenchymal transition (EMT) and the production and secretion of urokinase plasminogen activator (uPA) by inhibiting CFTR; on the other hand, miR-125b activated Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) signaling by repressing CGN. Therefore, we provided a potential biomarker for CRC prevention and treatment in the future.Metastasis contributes to the poor prognosis of colorectal cancer, the causative factor of which is not fully understood. Previously, we found that miR-125b (Accession number: MIMAT0000423) contributed to cetuximab resistance in colorectal cancer (CRC). In this study, we identified a novel mechanism by which miR-125b enhances metastasis by targeting cystic fibrosis transmembrane conductance regulator (CFTR) and the tight junction-associated adaptor cingulin (CGN) in CRC. We found that miR-125b expression was upregulated in primary CRC tumors and metastatic sites compared with adjacent normal tissues. Overexpression of miR-125b in CRC cells enhanced migration capacity, while knockdown of miR-125b decreased migration and invasion. RNA-sequencing (RNA-seq) and dual-luciferase reporter assays identified CFTR and CGN as the target genes of miR-125b, and the inhibitory impact of CFTR and CGN on metastasis was further verified both in vitro and in vivo. Moreover, we found that miR-125b facilitated the epithelial-mesenchymal transition (EMT) process and the expression and secretion of urokinase plasminogen activator (uPA) by targeting CFTR and enhanced the Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) pathway activity by targeting CGN. Together, these findings suggest miR-125b as a key functional molecule in CRC and a promising biomarker for the diagnosis and treatment of CRC.