Involvement of MicroRNAs in hydrogen peroxide-mediated gene regulation and cellular injury response in vascular smooth muscle cells

Physiological and cellular mechanisms of ischemic preconditioning microRNAs-mediated in underlying of ischemia/reperfusion injury in different organs

Ischemia-reperfusion (I/R) injury, as a pathological phenomenon, takes place when blood supply to an organ is disrupted and then aggravated during restoration of blood flow. Ischemic preconditioning (IPC) is a potent method for attenuating subsequent events of IR damage in numerous organs. IPC protocol is determined by a brief and sequential time periods of I/R before the main ischemia. MicroRNAs are endogenous non-coding RNAs that regulate post-transcriptionally target mRNA translation via degrading it and/or suppressing protein synthesis. This review introduces the physiological and cellular mechanisms of ischemic preconditioning microRNAs-mediated after I/R insult in different organs such as the liver, kidney, heart, brain, and intestine. Data of this review have been collected from the scientific articles published in databases such as Science Direct, Scopus, PubMed, Web of Science, and Scientific Information Database from 2000 to 2023. Based on these literature studies, IPC/IR intervention can affect cellular mechanisms including oxidative stress, apoptosis, angiogenesis, and inflammation through up-regulation or down-regulation of multiple microRNAs and their target genes.

MiR-181a protects the heart against myocardial infarction by regulating mitochondrial fission via targeting programmed cell death protein 4

Worldwide, myocardial infarction (MI) is the leading cause of death and disability-adjusted life years lost. Recent researches explored new methods of detecting biomarkers that can predict the risk of developing myocardial infarction, which includes identifying genetic markers associated with increased risk. We induced myocardial infarction in mice by occluding the left anterior descending coronary artery and performed TTC staining to assess cell death. Next, we performed ChIP assays to measure the enrichment of histone modifications at the promoter regions of key genes involved in mitochondrial fission. We used qPCR and western blot to measure expression levels of relative apoptotic indicators. We report that miR-181a inhibits myocardial ischemia-induced apoptosis and preserves left ventricular function after MI. We show that programmed cell death protein 4 (PDCD4) is the target gene involved in miR-181a-mediated anti-ischemic injury, which enhanced BID recruitment to the mitochondria. In addition, we discovered that p53 inhibits the expression of miR-181a via transcriptional regulation. Here, we discovered for the first time a mitochondrial fission and apoptosis pathway which is controlled by miR-181a and involves PDCD4 and BID. This pathway may be controlled by p53 transcriptionally, and we presume that miR-181a may lead to the discovery of new therapeutic and preventive targets for ischemic heart diseases.

Unraveling the Role of miR-200b-3p in Attention-Deficit/Hyperactivity Disorder (ADHD) and Its Therapeutic Potential in Spontaneously Hypertensive Rats (SHR)

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder in children with unknown etiology. Impaired learning ability was commonly reported in ADHD patients and has been associated with dopamine uptake in the striatum of an animal model. Another evidence also indicated that micro-RNA (miR)-200b-3p is associated with learning ability in various animal models. However, the association between miR-200b-3p and ADHD-related symptoms remains unclear. Therefore, the current study investigated the role of miR-200b-3p in ADHD-related symptoms such as inattention and striatal inflammatory cytokines. To verify the influence of miR-200b-3p in ADHD-related symptoms, striatal stereotaxic injection of miR-200b-3p antagomir (AT) was performed on spontaneously hypertensive rats (SHR). The antioxidant activity and expressions of miR-200b-3p, slit guidance ligand 2 (Slit2), and inflammatory cytokines in the striatum of SHR were measured using quantitative real-time polymerase chain reaction (RT-qPCR), immunohistochemistry (IHC), immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The spontaneous alternation of SHR was tested using a three-arm Y-shaped maze. The administration of miR-200b-3p AT or taurine significantly decreased striatal tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in SHR, along with increased super-oxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and significantly higher spontaneous alternation. In this paper, we show that miR-200b-3p AT and taurine alleviates ADHD-related symptoms in SHR. These findings provide insights into ADHD's molecular basis and suggest miR-200b-3p as a potential therapeutic target. Concurrently, this study also suggests broad implications for treating neurodevelopmental disorders affecting learning activity such as ADHD.

Stress-enhanced cardiac lncRNA Morrbid protects hearts from acute myocardial infarction

Myeloid RNA regulator of Bim-induced death (Morrbid) is a newly identified leukocyte-specific long noncoding RNA (lncRNA). However, the expression and biological functions of Morrbid in cardiomyocytes and heart disease are currently unclear. This study was meant to determine the role of cardiac Morrbid in acute myocardial infarction (AMI) and to identify the potential cellular and molecular mechanisms involved. We found that both human and mouse cardiomyocytes could express a significant amount of Morrbid and that its expression was increased in cardiomyocytes with hypoxia or oxidative stress as well as in mouse hearts with AMI. Overexpression of Morrbid reduced the myocardial infarct size and cardiac dysfunction, whereas the infarct size and cardiac dysfunction deteriorated in cardiomyocyte-specific Morrbid-KO (Morrbidfl/fl/Myh6-Cre) mice. We identified that Morrbid had a protective effect against hypoxia- or H2O2-induced apoptosis; this was also confirmed in vivo in mouse hearts after AMI. We further discovered that serpine1 was a direct target gene of Morrbid that was involved in the Morrbid-mediated protective effect on cardiomyocytes. In summary, we have found, for the first time to our knowledge, that the cardiac Morrbid is a stress-enhanced lncRNA that protects hearts from AMI via antiapoptosis through its target gene serpine1. Morrbid may be a novel promising therapeutic target for ischemic heart diseases such as AMI.

Long-Term LDL-Apheresis Treatment and Dynamics of Circulating miRNAs in Patients with Severe Familial Hypercholesterolemia

Lipoprotein apheresis (LA) is a therapeutic option for patients with severe hypercholesterolemia who have persistently elevated LDL-C levels despite attempts at drug therapy. MicroRNAs (miRNAs), important posttranscriptional gene regulators, are involved in the pathogenesis of atherosclerosis. Our study aimed to monitor the dynamics of twenty preselected circulating miRNAs in patients under long-term apheresis treatment. Plasma samples from 12 FH patients (men = 50%, age = 55.3 ± 12.2 years; mean LA overall treatment time = 13.1 ± 7.8 years) were collected before each apheresis therapy every sixth month over the course of four years of treatment. Eight complete follow-up (FU) samples were measured in each patient. Dynamic changes in the relative quantity of 6 miRNAs (miR-92a, miR-21, miR-126, miR-122, miR-26a, and miR-185; all p < 0.04) during FU were identified. Overall apheresis treatment time influenced circulating miR-146a levels (p < 0.04). In LDLR mutation homozygotes (N = 5), compared to heterozygotes (N = 7), we found higher plasma levels of miR-181, miR-126, miR-155, and miR-92a (all p < 0.03). Treatment with PCSK9 inhibitors (N = 6) affected the plasma levels of 7 miRNAs (miR-126, miR-122, miR-26a, miR-155, miR-125a, miR-92a, and miR-27a; all p < 0.04). Long-term monitoring has shown that LA in patients with severe familial hypercholesterolemia influences plasma circulating miRNAs involved in endothelial dysfunction, cholesterol homeostasis, inflammation, and plaque development. The longer the treatment using LA, the better the miRNA milieu depicting the potential cardiovascular risk.

Potential miRNA biomarkers and therapeutic targets for early atherosclerotic lesions

Identification of potential therapeutic targets and biomarkers indicative of burden of early atherosclerosis that occur prior to advancement to life-threatening unstable plaques is the key to eradication of CAD prevalence and incidences. We challenged 16 baboons with a high cholesterol, high fat diet for 2 years and evaluated early-stage atherosclerotic lesions (fatty streaks, FS, and fibrous plaques, FP) in formalin-fixed common iliac arteries (CIA). We used small RNA sequencing to identify expressed miRNAs in CIA and in baseline blood samples of the same animals. We found 412 expressed miRNAs in CIA and 356 in blood samples. Eight miRNAs (miR-7975, -486-5p, -451a, -191-5p, -148a-3p, -17-5p, -378c, and -144-3p) were differentially expressed between paired fatty streak lesion and no-lesion sites of the tissue, and 27 miRNAs (e.g., miR-92a-3p, -5001, -342-3p, miR-28-3p, -21-5p, -221-3p, 146a-5p, and -16-5p) in fibrous plaques. The expression of 14 blood miRNAs significantly correlated with extent of lesions and the number of plaques. We identified coordinately regulated miRNA-gene networks in which miR-17-5p and miR-146a-5p are central hubs and miR-5001 and miR-7975 are potentially novel miRNAs associated with early atherosclerosis. In summary, we have identified miRNAs expressed in lesions and in blood that correlate with lesion burden and are potential therapeutic targets and biomarkers. These findings are a first step in elucidating miRNA regulated molecular mechanisms that underlie early atherosclerosis in a baboon model, enabling translation of our findings to humans.

Role of c-Src and reactive oxygen species in cardiovascular diseases

Oxidative stress, caused by the over production of oxidants or inactivity of antioxidants, can modulate the redox state of several target proteins such as tyrosine kinases, mitogen-activated protein kinases and tyrosine phosphatases. c-Src is one such non-receptor tyrosine kinase which activates NADPH oxidases (Noxs) in response to various growth factors and shear stress. Interaction between c-Src and Noxs is influenced by cell type and primary messengers such as angiotensin II, which binds to G-protein coupled receptor and activates the intracellular signaling cascade. c-Src stimulated activation of Noxs results in elevated release of intracellular and extracellular reactive oxygen species (ROS). These ROS species disturb vascular homeostasis and cause cardiac hypertrophy, coronary artery disease, atherosclerosis and hypertension. Interaction between c-Src and ROS in the pathobiology of cardiac fibrosis is hypothesized to be influenced by cell type and stimuli. c-Src and ROS have a bidirectional relationship, thus increased ROS levels due to c-Src mediated activation of Noxs can further activate c-Src by promoting the oxidation and sulfenylation of critical cysteine residues. This review highlights the role of c-Src and ROS in mediating downstream signaling pathways underlying cardiovascular diseases. Furthermore, due to the central role of c-Src in activation of various signaling proteins involved in differentiation, migration, proliferation, and cytoskeletal reorganization of vascular cells, it is presented as therapeutic target for treating cardiovascular diseases except cardiac fibrosis.

Mutual Regulation between Redox and Hypoxia-Inducible Factors in Cardiovascular and Renal Complications of Diabetes

Oxidative stress and hypoxia-inducible factors (HIFs) have been implicated in the pathogenesis of diabetic cardiovascular and renal diseases. Reactive oxygen species (ROS) mediate physiological and pathophysiological processes, being involved in the modulation of cell signaling, differentiation, and survival, but also in cyto- and genotoxic damage. As master regulators of glycolytic metabolism and oxygen homeostasis, HIFs have been largely studied for their role in cell survival in hypoxic conditions. However, in addition to hypoxia, other stimuli can regulate HIFs stability and transcriptional activity, even in normoxic conditions. Among these, a regulatory role of ROS and their byproducts on HIFs, particularly the HIF-1α isoform, has received growing attention in recent years. On the other hand, HIF-1α and HIF-2α exert mutually antagonistic effects on oxidative damage. In diabetes, redox-mediated HIF-1α deregulation contributes to the onset and progression of cardiovascular and renal complications, and recent findings suggest that deranged HIF signaling induced by hyperglycemia and other cellular stressors associated with metabolic disorders may cause mitochondrial dysfunction, oxidative stress, and inflammation. Understanding the mechanisms of mutual regulation between HIFs and redox factors and the specific contribution of the two main isoforms of HIF-α is fundamental to identify new therapeutic targets for vascular complications of diabetes.

The Etiology and Molecular Mechanism Underlying Smooth Muscle Phenotype Switching in Intimal Hyperplasia of Vein Graft and the Regulatory Role of microRNAs

Mounting evidence suggests that the phenotypic transformation of venous smooth muscle cells (SMCs) from differentiated (contractile) to dedifferentiated (proliferative and migratory) phenotypes causes excessive proliferation and further migration to the intima leading to intimal hyperplasia, which represents one of the key pathophysiological mechanisms of vein graft restenosis. In recent years, numerous miRNAs have been identified as specific phenotypic regulators of vascular SMCs (VSMCs), which play a vital role in intimal hyperplasia in vein grafts. The review sought to provide a comprehensive overview of the etiology of intimal hyperplasia, factors affecting the phenotypic transformation of VSMCs in vein graft, and molecular mechanisms of miRNAs involved in SMCs phenotypic modulation in intimal hyperplasia of vein graft reported in recent years.

The Role and Interactions of Programmed Cell Death 4 and its Regulation by microRNA in Transformed Cells of the Gastrointestinal Tract

Data from GLOBOCAN 2020 estimates that there were 19.3 million new cases of cancer and 10.0 million cancer-related deaths in 2020 and that this is predicted to increase by 47% in 2040. The combined burden of cancers of the gastrointestinal (GI) tract, including oesophageal-, gastric- and colorectal cancers, resulted in 22.6% of the cancer-related deaths in 2020 and 18.7% of new diagnosed cases. Understanding the aetiology of GI tract cancers should have a major impact on future therapies and lessen this substantial burden of disease. Many cancers of the GI tract have suppression of the tumour suppressor Programmed Cell Death 4 (PDCD4) and this has been linked to the expression of microRNAs which bind to the untranslated region of PDCD4 mRNA and either inhibit translation or target the mRNA for degradation. This review highlights the properties of PDCD4 and documents the evidence for the regulation of PDCD4 expression by microRNAs in cancers of the GI tract.

Novel Biomarkers of Atherosclerotic Vascular Disease-Latest Insights in the Research Field

The atherosclerotic vascular disease is a cardiovascular continuum in which the main role is attributed to atherosclerosis, from its appearance to its associated complications. The increasing prevalence of cardiovascular risk factors, population ageing, and burden on both the economy and the healthcare system have led to the development of new diagnostic and therapeutic strategies in the field. The better understanding or discovery of new pathophysiological mechanisms and molecules modulating various signaling pathways involved in atherosclerosis have led to the development of potential new biomarkers, with key role in early, subclinical diagnosis. The evolution of technological processes in medicine has shifted the attention of researchers from the profiling of classical risk factors to the identification of new biomarkers such as midregional pro-adrenomedullin, midkine, stromelysin-2, pentraxin 3, inflammasomes, or endothelial cell-derived extracellular vesicles. These molecules are seen as future therapeutic targets associated with decreased morbidity and mortality through early diagnosis of atherosclerotic lesions and future research directions.

Involvement of miRNAs in response to oxidative stress induced by the steroidal glycoalkaloid α-solanine in hepatocellular carcinoma cells

BACKGROUND

α-Solanine is a natural toxic glycoalkaloid produced in some species of the Solanaceae family with antiproliferative activity in various cancers.

OBJECTIVE

This study aimed to investigate the effect of α-solanine on the oxidative stress status in human hepatocellular carcinoma HepG2 cells and to evaluate its influence on microRNAs (miRNAs) associated with oxidative stress and NF-κB regulation.

METHODS

The prooxidant effect of α-solanine was tested by the decay rate of the fluorescent probe, β-phycoerythrin, and by measuring malondialdehyde, reduced Glutathione, catalase, and superoxide dismutase following treatment of HepG2 cells with low doses of α-solanine. Immunocytochemical techniques were used to detect mitochondrial membrane potential (ΔΨm) and NF-κB protein. The gene expression of NF-κB and miRNAs was evaluated by real-time PCR.

RESULTS

α-Solanine is a prooxidant that causes a rapid decay in the fluorescence intensity of β-phycoerythrin. It induces oxidative stress-related alterations such as increased lipid peroxidation and reduced antioxidant markers. Oxidative stress induced by α-solanine was mediated by decreased ΔΨm, increased NF-κB expression, upregulation of miRNAs that control oxidative stress by regulating the NF-κB pathway, and downregulation of oncogenic miRNAs that inhibit the NF-κB pathway.

CONCLUSION

α-Solanine-induced oxidative stress is mediated by alterations in the NF-κB pathway with a detected crosstalk between α-solanine treatment and the expression of oxidative stress-responsive miRNAs.

Streptococcus gordonii-induced miRNAs regulate CCL20 responses in human oral epithelial cells

The mechanisms through which oral commensal bacteria mitigates uncontrolled inflammatory responses of the oral mucosa remain unknown. Here, we show that representative oral bacterial species normally associated with oral health [S. gordonii (Sg), V. parvula (Vp); A. naeslundii (An); C. sputigena (Cs), and N. mucosa (Nm)] enhanced differential chemokine responses in oral epithelial cells (OECs), with some bacteria (An, Vp, and Nm) inducing higher chemokine levels (CXCL1, CXCL8) than others (Sg, Cs). Although all bacterial species (except Cs) increased CCL20 mRNA levels consistent with protein elevations in cell lysates, only An, Vp and Nm induced higher CCL20 secretion, similar to the effect of the oral pathogen F. nucleatum (Fn). In contrast, most CCL20 remained associated with OECs exposed to Sg and negligible amounts released into the cell supernatants. Consistently, Sg attenuated An-induced CCL20. MiR-4516 and miR-663a were identified as Sg-specifically induced miRNAs modulating validated targets of chemokine-associated pathways. Cell transfection with miR-4516 and miR-663a decreased An- and Fn-induced CCL20. MiRNAs up-regulation and attenuation of An-induced CCL20 by Sg were reversed by catalase. Up-regulation of both miRNAs was specifically enhanced by oral streptococci H₂O₂-producers. These findings suggest that CCL20 levels produced by OECs in response to bacterial challenge are regulated by Sg-induced miR-4516 and miR-663a in a mechanism that involves hydrogen peroxide. This type of molecular mechanism could partly explain the central role of specific oral streptococcal species in balancing inflammatory and antimicrobial responses given the critical role of CCL20 in innate (antimicrobial) and adaptive immunity (modulates Th17 responses).

miR169q and NUCLEAR FACTOR YA8 enhance salt tolerance by activating PEROXIDASE1 expression in response to ROS

Salt stress significantly reduces the productivity of crop plants including maize (Zea mays). miRNAs are major regulators of plant growth and stress responses, but few studies have examined the potential impacts of miRNAs on salt stress responses in maize. Here, we show that ZmmiR169q is responsive to stress-induced ROS signals. After detecting that salt stress and exogenous H2O2 treatment reduced the accumulation of ZmmiR169q, stress assays with transgenic materials showed that depleting ZmmiR169q increased seedling salt tolerance whereas overexpressing ZmmiR169q decreased salt tolerance. Helping explain these observations, we found that ZmmiR169q repressed the transcript abundance of its target NUCLEAR FACTOR YA8 (ZmNF-YA8), and overexpression of ZmNF-YA8 in maize improved salt tolerance, specifically by transcriptionally activating the expression of the efficient antioxidant enzyme PEROXIDASE1. Our study reveals a direct functional link between salt stress and a miR169q-NF-YA8 regulatory module that plants use to manage ROS stress and strongly suggests that ZmNF-YA8 can be harnessed as a resource for developing salt-tolerant crop varieties.

Gene Expression of Antioxidant Enzymes in the Resected Intestine in Crohn's Disease

INTRODUCTION

The inflammatory process in Crohn's disease (CD) is closely associated with the formation of reactive oxygen species. Antioxidant enzymes can play an important role in the outcome of CD and may influence postoperative recurrence in these patients. The aim of our study was to evaluate gene expression of intracellular antioxidant enzymes in surgically resected intestinal specimens of patients with CD, both in macroscopically normal and in inflamed tissue.

METHODS

A total of 28 patients referred for elective bowel resection were enrolled in the study. Full-thickness small intestinal specimens were investigated. Gene expression of antioxidant enzymes - superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GSR) - was evaluated both in macroscopically normal and inflamed samples.

RESULTS

There were significantly lower levels of SOD1 mRNA (p = 0.007) and GSR mRNA (p = 0.027) in inflamed tissue compared to macroscopically normal areas. No significant differences were found between affected and non-affected intestinal segments in mRNA for SOD2, SOD3 and GPX.

CONCLUSIONS

Our pilot data clearly showed that the gene expression of major antioxidant enzymes is not a uniform mechanism in the pathogenesis of Crohn's disease. Topically decreased gene expression of SOD1 and GSR might facilitate the segmental tissue injury caused by reactive oxygen species.

Contribution of Oxidative Stress to HIF-1-Mediated Profibrotic Changes during the Kidney Damage

Hypoxia and oxidative stress are the common causes of various types of kidney injury. During recent years, the studies on hypoxia inducible factor- (HIF-) 1 attract more and more attention, which can not only mediate hypoxia adaptation but also contribute to profibrotic changes. Through analyzing related literatures, we found that oxidative stress can regulate the expression and activity of HIF-1α through some signaling molecules, such as prolyl hydroxylase domain-containing protein (PHD), PI-3K, and microRNA. And oxidative stress can take part in inflammation, epithelial-mesenchymal transition, and extracellular matrix deposition mediated by HIF-1 via interacting with classical NF-κB and TGF-β signaling pathways. Therefore, based on previous literatures, this review summarizes the contribution of oxidative stress to HIF-1-mediated profibrotic changes during the kidney damage, in order to further understand the role of oxidative stress in renal fibrosis.

Epigenetic plasticity and redox regulation of neural stem cell state and fate

The neural stem cells (NSCs) are essential for normal brain development and homeostasis. The cell state (i.e. quiescent versus activated) and fate (i.e. the cell lineage of choice upon differentiation) of NSCs are tightly controlled by various redox and epigenetic regulatory mechanisms. There is an increasing appreciation that redox and epigenetic regulations are intimately linked, but how this redox-epigenetics crosstalk affects NSC activity remains poorly understood. Another unresolved topic is whether the NSCs actually contribute to brain ageing and neurodegenerative diseases. In this review, we aim to 1) distill concepts that underlie redox and epigenetic regulation of NSC state and fate; 2) provide examples of the redox-epigenetics crosstalk in NSC biology; and 3) highlight potential redox- and epigenetic-based therapeutic opportunities to rescue NSC dysfunctions in ageing and neurodegenerative diseases.

microRNAs involved in psoriasis and cardiovascular diseases

Psoriasis is a chronic inflammatory disease involving the skin. Both genetic and environmental factors play a pathogenic role in psoriasis and contribute to the severity of the disease. Psoriasis, in fact, has been associated with different comorbidities such as diabetes, metabolic syndrome, gastrointestinal or kidney diseases, cardiovascular disease (CVD), and cerebrovascular diseases (CeVD). Indeed, life expectancy in severe psoriasis is reduced by up to 5 years due to CVD and CeVD. Moreover, patients with severe psoriasis have a higher prevalence of traditional cardiovascular (CV) risk factors, including dyslipidemia, diabetes, smoking, and hypertension. Further, systemic inflammation is associated with oxidative stress increase and induces endothelial damage and atherosclerosis progression. Different miRNA have been already described in psoriasis, both in the skin tissues and in the blood flow, to play a role in the progression of disease. In this review, we will summarize and discuss the most important miRNAs that play a role in psoriasis and are also linked to CVD.

Micro RNAs in Regulation of Cellular Redox Homeostasis

In living cells Reactive Oxygen Species (ROS) participate in intra- and inter-cellular signaling and all cells contain specific systems that guard redox homeostasis. These systems contain both enzymes which may produce ROS such as NADPH-dependent and other oxidases or nitric oxide synthases, and ROS-neutralizing enzymes such as catalase, peroxiredoxins, thioredoxins, thioredoxin reductases, glutathione reductases, and many others. Most of the genes coding for these enzymes contain sequences targeted by micro RNAs (miRNAs), which are components of RNA-induced silencing complexes and play important roles in inhibiting translation of their targeted messenger RNAs (mRNAs). In this review we describe miRNAs that directly target and can influence enzymes responsible for scavenging of ROS and their possible role in cellular redox homeostasis. Regulation of antioxidant enzymes aims to adjust cells to survive in unstable oxidative environments; however, sometimes seemingly paradoxical phenomena appear where oxidative stress induces an increase in the levels of miRNAs which target genes which are supposed to neutralize ROS and therefore would be expected to decrease antioxidant levels. Here we show examples of such cellular behaviors and discuss the possible roles of miRNAs in redox regulatory circuits and further cell responses to stress.

Diosmin Mitigates Cyclophosphamide Induced Premature Ovarian Insufficiency in Rat Model

The current study was designed to investigate the protective role of diosmin against cyclophosphamide-induced premature ovarian insufficiency (POI). Female Swiss albino rats received a single intraperitoneal dose of cyclophosphamide (200 mg/kg) followed by 8 mg/kg/day for the next 15 consecutive days either alone or in combination with oral diosmin at 50 or 100 mg/kg. Histopathological examination of ovarian tissues, hormonal assays for follicle stimulating hormone (FSH), estradiol (E2), and anti-Mullerian hormone (AMH), assessment of the oxidative stress status, as well as measurement of the relative expression of miRNA-145 and its target genes [vascular endothelial growth factor B (VEGF-B) and regulator of cell cycle (RGC32)] were performed. Diosmin treatment ameliorated the levels of E2, AMH, and oxidative stress markers. Additionally, both low and high diosmin doses significantly reduced the histopathological alterations and nearly preserved the normal ovarian reserve. MiRNA-145 expression was upregulated after treatment with diosmin high dose. miRNA-145 target genes were over-expressed after both low and high diosmin administration. Based on our findings, diosmin has a dose-dependent protective effect against cyclophosphamide-induced ovarian toxicity in rats.

The homeostatic role of hydrogen peroxide, superoxide anion and nitric oxide in the vasculature

Reactive oxygen and nitrogen species are produced in a wide range of physiological reactions that, at low concentrations, play essential roles in living organisms. There is a delicate equilibrium between formation and degradation of these mediators in a healthy vascular system, which contributes to maintaining these species under non-pathological levels to preserve normal vascular functions. Antioxidants scavenge reactive oxygen and nitrogen species to prevent or reduce damage caused by excessive oxidation. However, an excessive reductive environment induced by exogenous antioxidants may disrupt redox balance and lead to vascular pathology. This review summarizes the main aspects of free radical biochemistry (formation, sources and elimination) and the crucial actions of some of the most biologically relevant and well-characterized reactive oxygen and nitrogen species (hydrogen peroxide, superoxide anion and nitric oxide) in the physiological regulation of vascular function, structure and angiogenesis. Furthermore, current preclinical and clinical evidence is discussed on how excessive removal of these crucial responses by exogenous antioxidants (vitamins and related compounds, polyphenols) may perturb vascular homeostasis. The aim of this review is to provide information of the crucial physiological roles of oxidation in the endothelium, vascular smooth muscle cells and perivascular adipose tissue for developing safer and more effective vascular interventions with antioxidants.

MicroRNAs are critical in regulating smooth muscle cell mineralization and apoptosis during vascular calcification

Vascular calcification refers to the pathological deposition of calcium and phosphate minerals into the vasculature. It is prevalent in atherosclerosis, ageing, type 2 diabetes mellitus and chronic kidney disease, thus, increasing morbidity and mortality from these conditions. Vascular calcification shares similar mechanisms with bone mineralization, with smooth muscle cells playing a critical role in both processes. In the last decade, a variety of microRNAs have been identified as key regulators for the differentiation, phenotypic switch, proliferation, apoptosis, cytokine production and matrix deposition in vascular smooth muscle cells during vascular calcification. Therefore, this review mainly discusses the roles of microRNAs in the pathophysiological mechanisms of vascular calcification in smooth muscle cells and describes several interventions against vascular calcification by regulating microRNAs. As the exact mechanisms of calcification remain not fully elucidated, having a better understanding of microRNA involvement in vascular calcification may give impetus to development of novel therapeutics for the control and treatment of vascular calcification.

The Role of microRNAs in Metabolic Syndrome-Related Oxidative Stress

Oxidative stress (OxS) is the cause and the consequence of metabolic syndrome (MetS), the incidence and economic burden of which is increasing each year. OxS triggers the dysregulation of signaling pathways associated with metabolism and epigenetics, including microRNAs, which are biomarkers of metabolic disorders. In this review, we aimed to summarize the current knowledge regarding the interplay between microRNAs and OxS in MetS and its components. We searched PubMed and Google Scholar to summarize the most relevant studies. Collected data suggested that different sources of OxS (e.g., hyperglycemia, insulin resistance (IR), hyperlipidemia, obesity, proinflammatory cytokines) change the expression of numerous microRNAs in organs involved in the regulation of glucose and lipid metabolism and endothelium. Dysregulated microRNAs either directly or indirectly affect the expression and/or activity of molecules of antioxidative signaling pathways (SIRT1, FOXOs, Keap1/Nrf2) along with effector enzymes (e.g., GPx-1, SOD1/2, HO-1), ROS producers (e.g., NOX4/5), as well as genes of numerous signaling pathways connected with inflammation, insulin sensitivity, and lipid metabolism, thus promoting the progression of metabolic imbalance. MicroRNAs appear to be important epigenetic modifiers in managing the delicate redox balance, mediating either pro- or antioxidant biological impacts. Summarizing, microRNAs may be promising therapeutic targets in ameliorating the repercussions of OxS in MetS.

The carotid plaque as paradigmatic case of site-specific acceleration of aging process: The microRNAs and the inflammaging contribution

Atherosclerosis is considered a chronic inflammatory disease of arteries associated with the aging process. Many risk factors have been identified and they are mainly related to life-styles, gene-environment interactions and socioeconomic status. Carotid and coronary artery diseases are the two major atherosclerotic conditions, being the primary cause of stroke and heart attack, respectively. Nevertheless, carotid plaque assumes particular aspects not only for the specific molecular mechanisms, but also for the types of atheroma which may be associated with a better or a worst prognosis. The identification of circulating blood biomarkers able to distinguish carotid plaque types (stable or vulnerable) is a crucial step for the improvement of adequate therapeutic approaches avoiding or delaying endarterectomy in the oldest old individuals (> 80 years), a population predicted to growth in the next years. The review highlights the most recent knowledge on carotid plaque molecular mechanisms, focusing on microRNAs (miRs), as a site-specific accelerated aging within the conceptual framework of Geroscience for new affordable therapies.

The Interplay between Oxidative Stress and miRNAs in Obesity-Associated Hepatic and Vascular Complications

Nowadays, the obesity pandemic is one of the most relevant health issues worldwide. This condition is tightly related to comorbidities such as non-alcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVDs), namely atherosclerosis. Dysregulated lipid metabolism and inflammation link these three diseases, leading to a subsequent increase of oxidative stress (OS) causing severe cellular damage. On the other hand, microRNAs (miRNAs) are short, single-stranded, non-coding RNAs that act as post-transcriptional negative regulators of gene expression, thus being involved in the molecular mechanisms that promote the development of many pathologies including obesity and its comorbidities. The involvement of miRNAs in promoting or opposing OS in disease progression is becoming more evident. Some miRNAs, such as miR-200a and miR.421, seem to play important roles in OS control in NAFLD. On the other hand, miR-92a and miR-133, among others, are important in the development of atherosclerosis. Moreover, since both diseases are linked to obesity, they share common altered miRNAs, being miR-34a and miR-21 related to OS. This review summarizes the latest advances in the knowledge about the mechanisms of oxidative stress (OS) generation in obesity-associated NAFLD and atherosclerosis, as well as the role played by miRNAs in the regulation of such mechanisms.

LncRNA HCG18 is critical for vascular smooth muscle cell proliferation and phenotypic switching

Previous studies have shown that some specific long non-coding RNAs are dysregulated in vascular walls and abnormally expressed in vascular disease. LncRNA HLA complex group 18 (HCG18) is a member of the HLA complex group, which has been rarely investigated in human diseases. In this study, we aimed to investigate the role of HCG in vascular smooth muscle cells. HCG18 was over-expressed by adenovirus transfection and knocked down in vascular smooth muscle cells by shRNA. Cell proliferation was detected by CCK-8 assays. Flow cytometry was employed to test the impacts of HCG18 on vascular smooth muscle apoptotic cells. The expression of associated genes in protein and mRNA levels was detected by western blotting, immunofluorescence and qRT-PCR. The interactions between HCG18 and fused in sarcoma (FUS) were confirmed by RNA EMSA and RIP assays. The expression of serum HCG18 was decreased in hypertensive patients and PDGF-BB-treated vascular smooth muscle cells. HCG18 inhibited proliferation and induced apoptotic cells in vascular smooth muscle cells. In addition, we also found that HCG18 can inhibit vascular smooth muscle cell phenotypic switching from a contractile to a secretory phenotype. Finally, our results showed that HCG18 enhanced apoptotic cells by directly binding with FUS. Our findings reveal that HCG18 is involved in the regulation of proliferation, apoptosis and the expression levels of markers of the contractile and synthetic phenotype.

Redox modifications in synaptic components as biomarkers of cognitive status, in brain aging and disease

Aging is a natural process that includes several changes that gradually make organisms degenerate and die. Harman's theory proposes that aging is a consequence of the progressive accumulation of oxidative modifications mediated by reactive oxygen/nitrogen species, which plays an essential role in the development and progression of many neurodegenerative diseases. This review will focus on how abnormal redox modifications induced by age impair the functionality of neuronal redox-sensitive proteins involved in axonal elongation and guidance, synaptic plasticity, and intercellular communication. We will discuss post-transcriptional regulation of gene expression by microRNAs as a mechanism that controls the neuronal redox state. Finally, we will discuss how some brain-permeant antioxidants from the diet have a beneficial effect on cognition. Taken together, the evidence revised here indicates that oxidative-driven modifications of specific proteins and changes in microRNA expression may be useful biomarkers for aging and neurodegenerative diseases. Also, some specific antioxidant therapies have undoubtedly beneficial neuroprotective effects when administered in the correct doses, in the ideal formulation combination, and during the appropriate therapeutic window. The use of some antioxidants is, therefore, still poorly explored for the treatment of neurodegenerative diseases such as Alzheimer's disease.

Downregulation of microRNA‑106a‑5p alleviates ox‑LDL‑mediated endothelial cell injury by targeting STAT3

The apoptosis of endothelial cells (ECs) induced by oxidized low-density lipoprotein (ox-LDL) is an important contributing factor in the pathogenesis of atherosclerosis. It has been reported that microRNA (miR)-106a-5p is overexpressed in atherosclerotic plaques and involved in angiogenesis. However, its role and underlying mechanisms in ox-LDL induced EC apoptosis remain to be fully understood. In the present study the expression of miR-106a-5p in human umbilical vein ECs (HUVECs) stimulated with ox-LDL was investigated using reverse transcription-quantitative PCR analysis. Cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. Caspase-3 activity and reactive oxygen species (ROS) levels were determined by commercial kits. The interaction between miR-106a-5p and signal transducer and activator of transcription 3 (STAT3) mRNA was examined by luciferase reporter assay. It was found that ox-LDL treatment significantly increased the levels of miR-106a-5p in a dose-dependent manner in HUVECs. Moreover, these results demonstrated that ox-LDL treatment inhibited cell viability, promoted cell apoptosis, increased caspase-3 activity and ROS levels, whereas inhibition of miR-106a-5p reversed the effects of ox-LDL on HUVECs. In addition, it was shown that STAT3 is a direct target of miR-106a-5p in HUVECs, and silencing of STAT3 impaired the protective effects of miR-106a-5p inhibition on cell apoptosis and oxidative injury induced by ox-LDL. Collectively, these results indicated that miR-106a-5p participated in ox-LDL-stimulated apoptosis and oxidative injury in HUVECs by regulating STAT3. Thus, suggesting that miR-106a-5p/STAT3 may serve as a novel therapeutic target for atherosclerosis in the future.

The function of miR-200 family in oxidative stress response evoked in cancer chemotherapy and radiotherapy

Since the beginning of the discovery of microRNAs (miRs), these molecules have attracted highly progressive attention due to their powerful regulatory roles in a broad spectrum of biological processes, including proliferation, differentiation, apoptosis and carcinogenesis. With regard to carcinogenesis, the miRs regulatory potency has been associated with cancer onset, progression, metastasis, diagnosis and therapeutic response. In this review we discuss the impact of miR-200 family on drug resistance development during anti-cancer therapy. Developing resistance to chemotherapeutic drugs as well as radiotherapy are major clinical obstacles in the successful therapeutic strategies to cancer treatment. Acquired cancer chemoresistance is a multifactorial phenomenon involving such factors as tumor type, tumor stage, cellular reactive oxygen species (ROS) level or ROS-responsive miRs profile. ROS level could influence the miRs expression level, which changes the cellular profile of the content of miRs. Such significant changes in the cellular miRs profile generate subsequent biological effects through the regulation of their target genes. This review outlines the interactions between ROS and miR-200 family in different kinds of cancers in response to chemotherapy.

MicroRNAs as Therapeutic Targets and Clinical Biomarkers in Atherosclerosis

Atherosclerotic cardiovascular disease remains the leading cause of morbidity and mortality worldwide. Atherosclerosis develops over several decades and is mediated by a complex interplay of cellular mechanisms that drive a chronic inflammatory milieu and cell-to-cell interactions between endothelial cells, smooth muscle cells and macrophages that promote plaque development and progression. While there has been significant therapeutic advancement, there remains a gap where novel therapeutic approaches can complement current therapies to provide a holistic approach for treating atherosclerosis to orchestrate the regulation of complex signalling networks across multiple cell types and different stages of disease progression. MicroRNAs (miRNAs) are emerging as important post-transcriptional regulators of a suite of molecular signalling pathways and pathophysiological cellular effects. Furthermore, circulating miRNAs have emerged as a new class of disease biomarkers to better inform clinical diagnosis and provide new avenues for personalised therapies. This review focusses on recent insights into the potential role of miRNAs both as therapeutic targets in the regulation of the most influential processes that govern atherosclerosis and as clinical biomarkers that may be reflective of disease severity, highlighting the potential theranostic (therapeutic and diagnostic) properties of miRNAs in the management of cardiovascular disease.

Oxidative Stress Mechanisms in the Pathogenesis of Environmental Lung Diseases

Globally, respiratory diseases are major cause of disability and mortality, and more alarmingly, it disproportionately affects developing countries, which is largely attributed to poor quality of air. Tobacco smoke and emissions from combustion of fossil fuel and biomass fuel are the major airborne pollutants affecting human lung health. Oxidative stress is the dominant driving force by which the airborne pollutants exert their toxicity in lungs and cause respiratory diseases. Most airborne pollutants are associated with intrinsic oxidative potential and, additionally, stimulate endogenous production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Elevated ROS and RNS in lungs modulate redox signals and cause irreversible damage to critical biomolecules (lipids, proteins and DNA) and initiate various pathogenic cellular process. This chapter provides an insight into oxidative stress-linked pathogenic cellular process such as lipid peroxidation, inflammation, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, epigenetic changes, profibrotic signals and mucus hypersecretion, which drive the development and progression of lung diseases. Lungs are associated with robust enzymatic and non-enzymatic (GSH, ascorbic acid, uric acid, vitamin E) antioxidant defences. However, sustained production of free radicals due to continuous exposures to airborne pollutants overwhelms lung antioxidant defences and causes oxidative injury. Preclinical studies have demonstrated the critical roles and therapeutic potential of upregulating lung antioxidants for intervention of respiratory diseases; however, so far clinical benefits in antioxidant supplementation trials have been minimal and conflicting. Antioxidants alone may not be effective in treatment of respiratory diseases; however it could be a promising adjunctive therapy.

The role of microRNAs in the involvement of vascular smooth muscle cells in the development of atherosclerosis

MicroRNAs (miRNAs) are a class of nonprotein-encoding RNAs of ~22 nucleotides in length that bind to or complement each other with a target gene messenger RNA (mRNA) to promote mRNA degradation or inhibit translation of the target mRNA. The protein required [such as Toll-like receptor (TLR) proteins] is controlled at an optimal level. By affecting protein translation, miRNAs have become powerful regulators of biological processes, including development, differentiation, cell proliferation, and apoptosis. MiRNAs are involved in the regulation of proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs), thereby affecting the formation of atherosclerosis (AS). In recent years, the role and mechanism of miRNAs involved in AS development in VSMCs have been studied extensively. In the current study, the results and progress in miRNA research are reviewed.

MicroRNA-125b in vascular diseases: An updated systematic review of pathogenetic implications and clinical applications

Epigenetic changes, particularly non‐coding RNAs, have been implicated extensively in the pathogenesis of vascular diseases. Specific miRNAs are involved in the differentiation, phenotypic switch, proliferation, apoptosis, cytokine production and matrix deposition of endothelial cells and/or vascular smooth muscle cells. MicroRNA‐125b has been studied in depth for its role in carcinogenesis with a double‐edged role; that is, it can act as an oncogene in some cancer types and as a tumour suppressor gene in others. However, cumulative evidence from the use of advanced miRNA profiling techniques and bioinformatics analysis suggests that miR‐125b can be a potential mediator and useful marker of vascular diseases. Currently, the exact role of miR‐125b in vascular diseases is not known. In this systematic review, we intend to provide an updated compilation of all the recent findings of miR‐125b in vascular diseases, using a systematic approach of retrieving data from all available reports followed by data summarization. MiR‐125b serves as a pathogenic player in multiple vascular pathologies involving endothelia and vascular smooth muscle cells and also serves as a diagnostic marker for vascular diseases. We further provide a computational biologic presentation of the complex network of miR‐125b and its target genes within the scope of vascular diseases.

Pleiotropic microRNA-21 in pulmonary remodeling: novel insights for molecular mechanism and present advancements

MicroRNA-21 (miR-21), probably one of the most studied miRNAs to date, is found pleiotropic in various biological events. Its emerging role in pulmonary remodeling has attracted extensive attention. This review summarizes the genomic information of its primary transcript and various transcriptional regulations on its promoter. In addition, the role of miR-21 in pulmonary remodeling related signaling such as transforming growth factor β (TGF-β), bone morphogenetic protein (BMP), epidermal growth factor receptor (EGFR) and Notch signaling is discussed. Various validated miR-21 target genes participate in controlling of the overactive cell accumulation, smooth muscle contraction, inflammatory stress (trigger for lung epithelium damage), extracellular matrix deposition and hypoxia-induced disorders. Moreover, we focus on its particular implication in events including inflammatory stress-driven epithelium damage, epithelial-to-mesenchymal transition (EMT), transdifferentiation of fibroblasts into myofibroblasts, hypoxia stimuli and ROS response, as well as some other pulmonary remodeling related events such as overactive fibroblast (myofibroblast) accumulation, extracellular matrix deposition, and angiogenesis. Here, we summarize the strong potential of miR-21 in pulmonary remodeling and provide novel clues for further research in this area.

Amlodipine induces vasodilation via Akt2/Sp1-activated miR-21 in smooth muscle cells

BACKGROUND AND PURPOSE

The calcium antagonist amlodipine exerts important cardioprotective effects by modulating smooth muscle and endothelial functions. However, the mechanisms underlying these effects are incompletely understood.

EXPERIMENTAL APPROACH

Western blotting was used to compare the expression of key genes involved in vascular smooth muscle cell (VSMC) phenotype conversion. Recombinant adeno-associated virus system was used to regulate miRNA expression in rats via tail vein. Bioinformatics was used to predict the transcriptional regulation of miR-21 upstream followed by biochemical validation using quantitative real-time polymerase chain reaction, ChIP-qPCR and EMSA assays.

KEY RESULTS

Only the calcium antagonist amlodipine, and no other type of anti-hypertensive drug, induced miR-21 overexpression in plasma and aortic vessels in the animal model. Real-time PCR and luciferase assays showed that amlodipine induced miR-21 overexpression in vascular smooth muscle cells. Western blot and immunofluorescence assays demonstrated that amlodipine activated Akt2, rather than Akt1, followed by activation of transcription factor Sp1, which regulated VSMC phenotype conversion via binding to the miR-21 promoter. Furthermore, bioinformatic analyses and luciferase assays demonstrated that amlodipine activated miR-21 transcription at the -2034/-2027 Sp1-binding site, which was further demonstrated by ChIP-qPCR and EMSA assays. Consistently, small-interfering RNA-mediated knockdown of Akt2 and Sp1 significantly attenuated the effects of amlodipine on miR-21 expression in smooth muscle cells.

CONCLUSION AND IMPLICATIONS

These results indicate that amlodipine induces smooth muscle cell differentiation via miR-21, which is regulated by p-Akt2 and Sp1 nuclear translocation, thereby providing a novel target for cardiovascular diseases.

Leukocyte- and platelet-rich fibrin as graft material improves microRNA-21 expression and decreases oxidative stress in the calvarial defects of diabetic rabbits

OBJECTIVE

Leukocyte- and platelet-rich fibrin (L-PRF) represents a natural, low-cost product which may promote tissue healing by mechanisms not fully elucidated. Diabetes mellitus (DM) disrupts bone healing by inducing inflammation and oxidative stress (OS), mechanisms regulated by microRNAs (miRs). The aim of the present study was to investigate the microRNA-21 (miR-21) involvement in diabetic bone regeneration using L-PRF alone or in combination with a standard grafting material.

DESIGN

After the induction of diabetes (alloxan 100 mg/kg), four cranial osteotomies were made in diabetic (n = 12) and non-diabetic (n = 12) rabbits: one was left empty and the remaining three were grafted with L-PRF, bovine hydroxyapatite (Bio-Oss^®) and L-PRF + Bio-Oss®. Two and eight weeks postoperatively, the samples were harvested for miR-21 expression (Real-time RT-PCR) and enzyme-linked immunosorbent assay analyses.

RESULTS

Diabetic rabbits showed decreased miR-21 and matrix metalloproteinase-9 (MMP-9) protein expression while increased malondialdehyde (MDA) levels two weeks postoperatively; however, there were no significant differences in miR-21 and MMP-9 levels between diabetic and non-diabetic rabbits in samples taken eight weeks postoperatively. Application of L-PRF and L-PRF + Bio-Oss^® improved miR-21 and MMP-9 and decreased MDA levels while Bio-Oss® alone enhanced superoxide dismutase (SOD) activity levels in diabetic rabbits.

CONCLUSION

L-PRF alone or in combination with bovine hydroxyapatite as bone graft could be beneficial in DM since it seems to improve inflammation-modulatory miR-21 expression and decreases oxidative stress.

Effects of quercetin on microRNAs: A mechanistic review

MicroRNA (miRNA)-dependent pathways are one of the newest gene regulation mechanisms in various diseases, particularly in cancers. miRNAs are endogenous noncoding RNAs with about 18 to 25 nucleotide length, which can regulate the expression of at least 60% of human total genome posttranscriptionally. Quercetin is the most abundant flavonoid in a variety of fruits, flowers, and medical herbs, known as a strong free radical scavenger that could show antioxidant, anti-inflammatory, and antitumor activities. Recent studies also reported its strong impact on various miRNA expressions in different abnormalities. In this review, we aimed to summarize the studies focused on the effects of quercetin on different miRNA expressions to more clear the main possible mechanisms of quercetin influences and introduce it as a beneficial agent for regulation of miRNAs in various biological directions.

Dysregulated Expression of microRNA-21 and Disease-Related Genes in Human Patients and in a Mouse Model of Alport Syndrome

Alport syndrome is a genetic disease caused by mutations in type IV collagen and is characterized by progressive kidney disease. The Col4α3^-/- mouse model recapitulates the main features of human Alport syndrome. Previously, it was reported that kidney microRNA-21 (miR-21) expression is significantly increased in Col4α3^-/- mice, and administration of anti-miR-21 oligonucleotides (anti-miR-21) attenuates kidney disease progression in Col4α3^-/- mice, indicating that miR-21 is a viable therapeutic target for Alport syndrome. However, the expression pattern of miR-21 in the kidneys of patients with human Alport syndrome has not been evaluated. Paraffin-embedded kidney specimens were obtained from 27 patients with Alport syndrome and from 10 normal controls. They were evaluated for miR-21 expression and for in situ hybridization and mRNA expression by quantitative polymerase chain reaction. In addition, anti-miR-21 was administrated to Col4α3^-/- mice at different stages of disease, and changes in proteinuria, kidney function, and survival were monitored. Transcriptomic analysis of mouse kidney was conducted using RNA sequencing. miR-21 expression was significantly elevated in kidney specimens from patients with Alport syndrome compared to normal controls. Elevated renal miR-21 expression positively correlated with 24 h urine protein, serum blood urea nitrogen, serum creatinine, and severity of kidney pathology. On histological evaluation, high levels of miR-21 were localized to damaged tubular epithelial cells and glomeruli. Kidney specimens from both humans and mice with Alport syndrome exhibited abnormal expression of genes involved in kidney injury, fibrosis, inflammation, mitochondrial function, and lipid metabolism. Administration of anti-miR-21 to Alport mice resulted in slowing of kidney function decline, partial reversal of abnormal gene expression associated with disease pathology, and improved survival. Increased levels of miR-21 in human Alport kidney samples showed a correlation with kidney disease severity measured by proteinuria, biomarkers of kidney function, and kidney histopathology scores. These human data, combined with the finding that a reduction of miR-21 in Col4α3^-/- mice improves kidney phenotype and survival, support miR-21 as a viable therapeutic target for the treatment of Alport syndrome.

Ionizing radiation-induced growth in soft agar is associated with miR-21 upregulation in wild-type and DNA double strand break repair deficient cells

DNA double strand breaks (DSBs) are a severe threat to genome integrity and a potential cause of tumorigenesis, which is a multi-stage process and involves many factors including the mutation of oncogenes and tumor suppressors, some of which are transcribed microRNAs (miRNAs). Among more than 2000 known miRNAs, miR-21 is a unique onco-miRNA that is highly expressed in almost all types of human tumors and is associated with tumorigenesis through its multiple targets. However, it remains unclear whether there is any functional link between DSBs and miR-21 expression and, if so, does the link contribute to DSB-induced genomic instability/tumorigenesis. To address this question, we used DNA-PKcs-/- (deficient in non-homologous end-joining (NHEJ)) and Rad54-/- (deficient in homologous recombination repair (HRR)) mouse embryonic fibroblasts (MEFs) since NHEJ and HRR are the major pathways for DSB repair in mammalian cells. Our results indicate that levels of miR-21 are elevated in these DSB repair (DSBR) deficient cells, and ionizing radiation (IR) further increases these levels in both wild-type (WT) and DSBR-deficient cells. Interestingly, IR stimulated growth in soft agar and this effect was greatly reduced by blocking miR-21 expression in both WT and DSBR-deficient cells. Taken together, our results suggest that either IR or DSBR-deficient can lead to an upregulation of miR-21 levels and that miR-21 is associated with IR-induced cell growth in soft agar. These results may help our understanding of DSB-induced tumorigenesis and provide information that could facilitate the development of new strategies to prevent DSB-induced carcinogenesis.

Noncoding RNAs in the Vascular System Response to Oxidative Stress

SIGNIFICANCE

Redox homeostasis plays a pivotal role in vascular cell function and its imbalance has a causal role in a variety of vascular diseases. Accordingly, the response of mammalian cells to redox cues requires precise transcriptional and post-transcriptional modulation of gene expression patterns. Recent Advances: Mounting evidence shows that nonprotein-coding RNAs (ncRNAs) are important for the functional regulation of most, if not all, cellular processes and tissues. Not surprisingly, a prominent role of ncRNAs has been identified also in the vascular system response to oxidative stress.

CRITICAL ISSUES

The highly heterogeneous family of ncRNAs has been divided into several groups. In this article we focus on two classes of regulatory ncRNAs: microRNAs and long ncRNAs (lncRNAs). Although knowledge in many circumstances, and especially for lncRNAs, is still fragmentary, ncRNAs are clinically interesting because of their diagnostic and therapeutic potential. We outline ncRNAs that are regulated by oxidative stress as well as ncRNAs that modulate reactive oxygen species production and scavenging. More importantly, we describe the role of these ncRNAs in vascular physiopathology and specifically in disease conditions wherein oxidative stress plays a crucial role, such as hypoxia and ischemia, ischemia reperfusion, inflammation, diabetes mellitus, and atherosclerosis.

FUTURE DIRECTIONS

The therapeutic potential of ncRNAs in vascular diseases and in redox homeostasis is discussed.

Exosomes from mesenchymal stem cells expressing miR-125b inhibit neointimal hyperplasia via myosin IE

Intercellular communication between mesenchymal stem cells (MSCs) and their target cells in the perivascular environment is modulated by exosomes derived from MSCs. However, the potential role of exosome-mediated microRNA transfer in neointimal hyperplasia remains to be investigated. To evaluate the effects of MSC-derived exosomes (MSC-Exo) on neointimal hyperplasia, their effects upon vascular smooth muscle cell (VSMC) growth in vitro and neointimal hyperplasia in vivo were assessed in a model of balloon-induced vascular injury. Our results showed that MSC-Exo were internalised by VSMCs and inhibited proliferation and migration in vitro. Further analysis revealed that miR-125b was enriched in MSC-Exo, and repressed the expression of myosin 1E (Myo1e) by targeting its 3' untranslated region. Additionally, MSC-Exo and exosomally transferred miR-125b repressed Myo1e expression and suppressed VSMC proliferation and migration and neointimal hyperplasia in vivo. In summary, our findings revealed that MSC-Exo can transfer miR-125b to VSMCs and inhibit VSMC proliferation and migration in vitro and neointimal hyperplasia in vivo by repressing Myo1e, indicating that miR-125b may be a therapeutic target in the treatment of vascular diseases.

Protective Action of Diazoxide on Isoproterenol-Induced Hypertrophy Is Mediated by Reduction in MicroRNA-132 Expression

INTRODUCTION AND METHODS

The effects of diazoxide on cardiac hypertrophy and miR-132 expression were characterized in adult rats and in cardiomyocytes. Diazoxide effects on reactive oxygen species (ROS) production and on the cAMP-response element binding (CREB) transcription factor's abundance in cardiomyocytes were also analyzed. ROS measurements used a fluorescent dye. Western blot analysis and quantitative Reverse Transcription Polymerase Chain Reaction were used to measure phosphorylated form of CREB (pCREB) abundance and miR-132 expression, respectively.

RESULTS

Isoproterenol (ISO) induced cardiac hypertrophy, an effect that was mitigated by diazoxide. The rate of ROS production, CREB phosphorylation, and miR-132 expression increased after the addition of ISO. H2O2 increased pCREB abundance and miR-132 expression; upregulation of miR-132 was blocked by the specific inhibitor of CREB transcription, 666-15. Consistent with a role of ROS on miR-132 expression, diazoxide prevented the increase in ROS production, miR-132 expression, and pCREB abundance produced by ISO. Phosphorylation of CREB by ISO was prevented by U0126, an inhibitor of mitogen-activated protein kinase.

CONCLUSIONS

Our data first demonstrate that diazoxide mitigates hypertrophy by preventing an increase in miR-132 expression. The mechanism likely involves less ROS production leading to less phosphorylation of CREB. Our data further show that ROS enhance miR-132 transcription, and that ISO effects are probably mediated by the mitogen-activated protein kinase pathway.

[Effect of miR-21 down-regulated by H 2O 2 on osteogenic differentiation of MC3T3-E1 cells]

Objective

To explore the effect and mechanism of miR-21 down-regulated which was induced by H ₂O ₂ on osteogenic differentiation of MC3T3-E1 cells.

Methods

MC3T3-E1 cells were cultured and passaged, and the 7th generation cells were harvested to use in experiment. The MC3T3-E1 cells were treated with different concentrations (0, 40, 80, 160, and 320 μmol/L) of H ₂O ₂. The expression of miR-21 was detected by real-time quantitative PCR (RT-PCR) and the cell viability was determined by MTS. Then the appropriate concentration of H ₂O ₂ was obtained. To analyze the effect of H ₂O ₂ on osteogenic differentiation of MC3T3-E1 cells, the MC3T3-E1 cells were divided into blank control group (group A), H ₂O ₂ group (group B), osteogenic induction group (group C), and H ₂O ₂+osteogenic induction group (group D). The expression of miR-21 and the osteogenesis related genes expressions of Runx2, osteopontin (OPN), and collagen type Ⅰ alpha 1 (Col1a1) were detected by RT-PCR. The expression of phosphatase and tensin homolog (PTEN) was detected by Western blot. The extracellular calcium deposition was detected by alizarin red staining. To analyze the effect on osteogenic differentiation of MC3T3-E1 cells after the transfection of miR-21 inhibitor and siRNA-PTEN, the MC3T3-E1 cells were divided into H ₂O ₂ group (group A1), H ₂O ₂+osteogenic induction group (group B1), H ₂O ₂+osteogenic induction+miR-21 inhibitor group (group C1), and H ₂O ₂+osteogenic induction+miR-21 inhibitor negative control group (group D1); and H ₂O ₂ group (group A2), H ₂O ₂+osteogenic induction group (group B2), H ₂O ₂+osteogenic induction+siRNA-PTEN negative control group (group C2), and H ₂O ₂+osteogenic induction+siRNA-PTEN group (group D2). The osteogenesis related genes were detected by RT-PCR and the extracellular calcium deposition was detected by alizarin red staining.

Results

The results of MTS and RT-PCR showed that the appropriate concentration of H ₂O ₂ was 160 μmol/L. The expression of miR-21 was significantly lower in group B than in group A at 1 and 2 weeks ( P<0.05). The expression of miR-21 was significantly lower in group D than in group C at 1 and 2 weeks ( P<0.05). The expression of PTEN protein was significantly lower in group C than in groups A and D ( P<0.05). The mRNA expressions of Runx2, OPN, and Col1a1 were significantly lower in group D than in group C at 1 and 2 weeks ( P<0.05). The extracellular calcium deposition in group D was obviously less than that in group C. The expression of PTEN protein was significantly higher in group C1 than in group D1 ( P<0.05). The mRNA expressions of Runx2 and OPN were significantly lower in group C1 than in groups B1 and D1 at 1 and 2 weeks ( P<0.05). The mRNA expression of Col1a1 was significantly lower in group C1 than in groups B1 and D1 at 2 weeks ( P<0.05). The extracellular calcium deposition in group C1 was obviously less than those in groups B1 and D1. The mRNA expressions of OPN and Col1a1 were significantly higher in group D2 than in groups B2 and C2 at 1 week ( P<0.05). The extracellular calcium deposition in group D2 was obviously more than those in groups B2 and C2.

Conclusion

H ₂O ₂ inhibits the osteogenic differentiation of MC3T3-E1 cells, which may be induced by down-regulating the expression of miR-21.

Protective and therapeutic potential of ginger (Zingiber officinale) extract and [6]-gingerol in cancer: A comprehensive review

Natural dietary agents have attracted considerable attention due to their role in promoting health and reducing the risk of diseases including cancer. Ginger, one of the most ancient known spices, contains bioactive compounds with several health benefits. [6]-Gingerol constitutes the most pharmacologically active among such compounds. The aim of the present work was to review the literature pertaining to the use of ginger extract and [6]-gingerol against tumorigenic and oxidative and inflammatory processes associated with cancer, along with the underlying mechanisms of action involved in signaling pathways. This will shed some light on the protective or therapeutic role of ginger derivatives in oxidative and inflammatory regulations during metabolic disturbance and on the antiproliferative and anticancer properties. Data collected from experimental (in vitro or in vivo) and clinical studies discussed in this review indicate that ginger extract and [6]-gingerol exert their action through important mediators and pathways of cell signaling, including Bax/Bcl2, p38/MAPK, Nrf2, p65/NF-κB, TNF-α, ERK1/2, SAPK/JNK, ROS/NF-κB/COX-2, caspases-3, -9, and p53. This suggests that ginger derivatives, in the form of an extract or isolated compounds, exhibit relevant antiproliferative, antitumor, invasive, and anti-inflammatory activities.

Redox Regulation and Noncoding RNAs

SIGNIFICANCE

RNA is a heterogeneous class of molecules with the minority being protein coding. Noncoding RNAs (ncRNAs) are involved in translation and epigenetic control mechanisms of gene expression. Recent Advances: In recent years, the number of identified ncRNAs has dramatically increased and it is now clear that ncRNAs provide a complex layer of differential gene expression control.

CRITICAL ISSUES

NcRNAs exhibit interplay with redox regulation. Redox regulation alters the expression of ncRNAs; conversely, ncRNAs alter the expression of generator and effector systems of redox regulation in a complex manner, which will be the focus of this review article.

FUTURE DIRECTIONS

Understanding the role of ncRNA in redox control will lead to the development of new strategies to alter redox programs. Given that many ncRNAs (particularly microRNAs [miRNAs]) change large gene sets, these molecules are attractive drug candidates; already, now miRNAs can be targeted in patients. Therefore, the development of ncRNA therapies focusing on these molecules is an attractive future strategy. Antioxid. Redox Signal. 29, 793-812.