Role Of miR-34c Research Articles

Extracellular vesicles derived from hypoxia-preconditioned bone marrow mesenchymal stem cells ameliorate lower limb ischemia by delivering miR-34c.

Hypoxic mesenchymal stem cell-derived extracellular vesicles (EVs) have been suggested as a promising therapy for various diseases. This study aims to determine the effect of EVs derived from bone marrow mesenchymal stem cells (BMMSCs) under hypoxia on lower limb ischemia and the underlying mechanism. Human BMMSCs were subjected to hypoxia or normoxia followed by the isolation of EVs. Nanoparticle trafficking analysis (NTA), transmission electron microscopy (TEM), and Western Blotting using corresponding markers were performed to confirm the EVs. The EVs from BMMSCs under hypoxia condition (Hyp-EVs) or normoxia condition (Nor-EVs) were subjected to hindlimb ischemia (HI) mice. MiR-34c expression in BMMSCs and BMMSC-EVs was detected. The role of miR-34c in regulating M2 macrophage polarization, as well as the target of miR-34c, were explored. HI mice with Hyp-EV treatment, as compared to the Nor-EV or the PBS group, had better blood flow and higher capillary density. MiR-34c expression was increased in BMMSCs, BMMSC-EVs, and the adductor muscle of HI mice. Hyp-EVs promoted the M2 macrophage polarization and anti-inflammatory cytokine production, and enhanced the blood flow and capillary density in HI mice, while the knockdown of miR-34c partly reversed these effects. PTEN is a target of miR-34c, and the PTEN silencing facilitated M2 macrophage polarization, whereas the inhibition of AKT signaling partly abolished the effect. Hyp-EVs promoted M2 macrophage polarization by delivering miR-34c via PTEN/AKT pathway, which could be a promising therapeutic strategy to ameliorate lower limb ischemia.

MicroRNA‐34c suppresses proliferation of vascular smooth muscle cell via modulating high mobility group box protein 1

BackgroundAtherosclerosis is the most frequent pathological process that causes cardiovascular diseases.ObjectiveThe present study aimed to confirm miRNAs associated with atherosclerosis and explore the molecular mechanism of miR‐34c and its target high mobility group box protein 1 (HMGB1) in the control of growth of smooth muscle cells in the development of atherosclerosis.MethodsReal‐time PCR was firstly performed to confirm miRNA correlation with atherosclerosis, and computational analysis and luciferase assay were performed to explore the target of miR‐34c, Western blot, and real‐time PCR were also utilized to reveal the effect of whether high glucose (HG) and miR‐34c affect miR‐34c, HMGB1 levels, NF‐κB p65 and TNF‐α levels, and the role of miR‐34c on vascular smooth muscle cells (VSMCs) viability induced by HG. Students' unpaired t test was performed to compare data between two groups.ResultsMiR‐34c level was associated with atherosclerosis with different expression between VSMCs treated with high glucose or normal VSMCs. Then, HMGB1 is a virtual target of miR‐34c with predicted binding site resided in HMGB1 3′UTR and further verified by that miR‐34c remarkably reduced luciferase activity of wild HMGB1 3′UTR under a concentration‐dependent fashion, and miR‐34c cannot influence luciferase activity of mutant HMGB1 3′UTR.ConclusionsThe results suggested miR‐34c might be a novel therapeutic strategy in the management of atherosclerosis by suppressing the expression of HGMB1 and its downstream effectors.

Role of miR-34c in the cognitive function of epileptic rats induced by pentylenetetrazol.

Studies suggest that microRNA (miR)-34c may serve a role in cognitive function in rodent and primate groups. A previous study demonstrated an increase in miR-34c expression in chronic epileptic rats with memory disorders, induced by pentylenetetrazol (PTZ). However, the mechanism underlying the effects of miR-34c on cognitive function in epileptic rats remains unclear. Therefore, the present study investigated alterations in cognitive function in temporal lobe epileptic rats, induced by repeated injections of PTZ, following treatment with an miR-34c agomir compared with a scramble group. Increased expression of miR-34c was observed in the agomir group, in addition to an increased deficit in learning and memory function in the Morris water maze test. Glutamate receptor ionotropic N-methyl-D-aspartate (NMDA) 2B (NR2B), phosphorylated (p)-reduced nicotinamide-adenine dinucleotide phosphate-dependent diflavin oxidoreductase 1 (NR1) and p-glutamate receptor 1 (GluR1) protein expression was detected in the hippocampus using western blotting. Additionally, the downregulation of NR2B, p-NR1 and p-GluR1 in the miR-34c agomir group demonstrated that miR-34c may serve a negative role in cognitive function in epileptic seizures, by dysregulating NMDA and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, which are associated with long-term potentiation.

Role of miR-34c in ketamine-induced neurotoxicity in neonatal mice hippocampus.

Ketamine is a commonly used pediatric anesthetic, but it might affect development, or even induce neurotoxicity in the neonatal brain. We have used an in vivo neonatal mouse model to induce ketamine-related neurotoxicity in the hippocampus, and found that miR-34c, a microRNA associated with pathogenesis of Alzheimer's disease, was significantly upregulated during ketamine-induced hippocampal neurodegeneration. Functional assay of silencing miR-34c demonstrated that downregulation of miR-34c activated PKC-ERK pathway, upregulated anti-apoptotic protein BCL2, and ameliorated ketamine-induced apoptosis in the hippocampus. Cognitive examination with the Morris water maze test showed that ketamine-induced memory impairment was significantly improved by miR-34c downregulation. Thus, miR-34c is important in regulating ketamine-induced neurotoxicity in hippocampus.

Differential effects of miR-34c-3p and miR-34c-5p on the proliferation, apoptosis and invasion of glioma cells

Glioblastoma is the most malignant and common intrinsic brain tumor, but the molecular mechanism of glioma pathophysiology is poorly understood. Recent data have shown that microRNAs regulate the expression of several genes associated with human cancer. In the present study, the function of miR-34c in glioma cells was analyzed. It was demonstrated that miR-34c-3p and miR-34c-5p were downregulated in gliomas, by performing qPCR on tumor tissues from glioma patients and glioma cell lines, compared with normal brain tissues and a normal glial cell line. Furthermore, the miR-34c expression was found to be inversely correlated with glioma WHO grades. Overexpression of miR-34c-3p inhibited U251 and U87 cell proliferation; however, miR-34c-5p only had an effect on U251 cells. Transfection with miR-34c-3p or miR-34c-5p in U251 cells and with miR-34c-3p in U87 cells produced S-phase arrest with G0/G1 reduction and induced cell apoptosis, but no significant changes were observed with miR-34c-5p transfection in U87 cells, normal or negative control groups. However, significant inhibition of glioma cell invasion was observed following transfection with miR-34c-3p and miR-34c-5p. Moreover, it was identified that miR-34c-3p overexpression reduced the expression of Notch pathway members, but miR-34c-5p overexpression did not. Therefore, these results suggest differential tumor suppressor roles for miR-34c-3p and miR-34c-5p and provide new insights into the role of miR-34c in glioma, which includes tumor-suppressing effects on proliferation, apoptosis and invasiveness.

MiR‐34c is downregulated in prostate cancer and exerts tumor suppressive functions

MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally regulate gene expression. There have been several reports of miRNA deregulation in prostate cancer (PCa) and the biological evidence for an involvement of miRNAs in prostate tumorigenesis is increasing. In this study, we show that miR-34c is downregulated in PCa (p = 0.0005) by performing qRT-PCR on 49 TURPs from PCa patients compared to 25 from patients with benign prostatic hyperplasia. The miR-34c expression was found to inversely correlate to aggressiveness of the tumor, WHO grade, PSA levels and occurrence of metastases. Furthermore, a Kaplan-Meier analysis of patient survival based on miR-34c expression levels divided into low (< 50th percentile) and high (> 50th percentile) expression, significantly divides the patients into high risk and low risk patients (p = 0.0003, log-rank test). The phenotypic effects of miR-34c deregulation were studied in prostate cell lines, where ectopic expression of miR-34c decreased cell growth, due to both a decrease in cellular proliferation rate and an increase in apoptosis. In concordance to this, miR-34c was found to negatively regulate the oncogenes E2F3 and BCL-2, which stimulates proliferation and suppress apoptosis in PCa cells, respectively. Reversely, we could also show that blocking miR-34c in vitro increases cell growth. Further, ectopic expression of miR-34c was found to suppress migration and invasion. Our findings provide new insight into the role of miR-34c in the prostate, exhibiting tumor suppressing effects on proliferation, apoptosis and invasiveness.