Involvement of MicroRNAs in hydrogen peroxide-mediated gene regulation and cellular injury response in vascular smooth muscle cells.
ABSTRACT MicroRNAs (miRNAs) comprise a novel class of endogenous, small, noncoding RNAs that negatively regulate approximately 30% of genes in a cell via degradation or translational inhibition of their target mRNAs. However, the effects of reactive oxygen species (ROS) on miRNA expression and the roles of miRNAs in ROS-mediated gene regulation and biological functions of vascular cells are unclear. Using microarray analysis, we demonstrated that miRNAs are aberrantly expressed in vascular smooth muscle cells (VSMCs) after treatment with hydrogen peroxide (H(2)O(2)). H(2)O(2)-mediated up-regulation of microRNA-21 (miR-21) was further confirmed by quantitative real-time PCR. To determine the potential roles of miRNAs in H(2)O(2)-mediated gene regulation and cellular effects, miR-21 expression was down-regulated by miR-21 inhibitor and up-regulated by pre-miR-21. H(2)O(2)-induced VSMC apoptosis and death were increased by miR-21 inhibitor and decreased by pre-miR-21. Programmed cell death 4(PDCD4) was a direct target of miR-21 that was involved in miR-21-mediated effects on VSMCs. Pre-miR-21-mediated protective effect on VSMC apoptosis and death was blocked via adenovirus-mediated overexpression of PDCD4 without the miR-21 binding site. Moreover, activator protein 1 was a downstream signaling molecule of PDCD4 in miR-21-modulated VSMCs. The results suggest that miRNAs in VSMCs are sensitive to H(2)O(2) stimulation. miRN-21 participates in H(2)O(2)-mediated gene regulation and cellular injury response through PDCD4 and the activator protein 1 pathway. miRNAs might play a role in vascular diseases related to ROS.
- SourceAvailable from: Namrata Rastogi[Show abstract] [Hide abstract]
ABSTRACT: The natural polyphenolic alkanone, (6)-Gingerol (6G) has established anti-inflammatory and anti-tumoral properties. However, its precise mechanism of action in myeloid leukemia cells is unclear. In this study, we investigated the effects of 6G on myeloid leukemia cells in vitro and in vivo. The results of the present study showed that 6G inhibited proliferation of myeloid leukemia cell lines and primary myeloid leukemia cells while sparing the normal peripheral blood mononuclear cells (PBMCs), in a concentration and time dependent manner. Mechanistic studies using U937 and K562 cell lines revealed that 6G treatment induced ROS generation by inhibiting the mitochondrial respiratory complex-I (MRC-I) which in turn increased the expression of the oxidative stress response associated microRNA, miR-27b and DNA damage. Elevated miR-27b expression inhibited PPARγ with subsequent inhibition of the inflammatory cytokine gene expression associated with the oncogenic NF-kappaB (NFkB) pathway, while the increased DNA damage led to G2/M cell cycle arrest. The 6G induced effects were abolished in the presence of anti-miR27b or the ROS scavenger NAC. In addition, the results of the in vivo xenograft experiments in mice indicated that 6G treatment inhibited tumor cell proliferation and induced apoptosis in agreement with the in vitro studies. Our data provide new evidence that 6G induced myeloid leukemia cell death is initiated by the reactive oxygen species and mediated through the increase in miR-27b expression and DNA damage. The dual induction of increased miR-27b expression and DNA damage associated cell cycle arrest by 6G may have implications for myeloid leukemia treatment.Free Radical Biology and Medicine 12/2013; 68. DOI:10.1016/j.freeradbiomed.2013.12.016 · 5.71 Impact Factor
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ABSTRACT: The regulation of cholesterol metabolism is one of the most studied biological processes since its first isolation from gallstones in 1784. High levels of plasma low-density lipoprotein (LDL) cholesterol and reduced levels of plasma high-density lipoprotein (HDL) cholesterol are widely recognized as major risk factors of cardiovascular disease. An imbalance in the production of reactive oxygen species (ROS) can oxidize LDL particles increasing the levels of the highly pro-atherogenic oxidized LDLs (ox-LDLs). Furthermore, under pathological scenarios, numerous molecules can function as pro-oxidants, such as iron or high-glucose levels. In addition to the classical mechanisms regulating lipid homeostasis, recent studies have demonstrated the important role of microRNAs (miRNAs) as regulators of lipoprotein metabolism, its oxidative derivatives and redox balance. Here, we summarize the recent findings in the field, highlighting the contribution of some miRNAs in lipid and oxidative-associated pathologies. We also discuss how therapeutic intervention of miRNAs may be a promising strategy to decrease LDL, increase HDL and ameliorate lipid and oxidative related disorders, including atherosclerosis, non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome.Free Radical Biology and Medicine 07/2013; 64. DOI:10.1016/j.freeradbiomed.2013.07.014 · 5.71 Impact Factor
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ABSTRACT: We previously reported the involvement of conventional protein kinase C (cPKC) βII, γ, novel PKC (nPKC) ε and their interacting proteins in hypoxic pre-conditioning (HPC)-induced neuroprotection. In this study, the large-scale miRNA microarrays and bioinformatics analysis were used to determine the differentially expressed miRNAs and their PKC-isoform specific gene network in mouse brain after HPC and 6 h middle cerebral artery occlusion (MCAO). We found 4 up-regulated and 13 down-regulated miRNAs in the cortex of HPC mice, 26 increased and 39 decreased gene expressions of miRNAs in the peri-infarct region of 6 h MCAO mice, and 11 up-regulated and 22 down-regulated miRNAs in the peri-infarct region of HPC and 6 h MCAO mice. Based on Diff Score, 19 differentially expressed miRNAs were identified in HPC and 6 h MCAO mouse brain. Then the miRNA-gene-network of 19 specified miRNAs target genes of cPKCβII, γ and nPKCε-interacting protein was predicted by using bioinformatics analysis of genome databases. Furthermore, the down-regulated miR-615-3p during HPC had a detrimental effect on the oxygen-glucose deprivation (OGD)-induced N2A cell injury. These results suggested that the identified 19 miRNAs, notably miR-615-3p, might target these genes of cPKCβII, γ and nPKCε-interacting proteins involved in HPC-induced neuroprotection.Journal of Neurochemistry 12/2011; 120(5):830-41. DOI:10.1111/j.1471-4159.2011.07624.x · 4.24 Impact Factor