Oxidative stress in metabolic diseases: current scenario and therapeutic relevance.

The metabolic syndrome is a clustering condition of increased abdominal obesity in concert with hyperglycemia, insulin resistance, hypertension, and dyslipidemia. It confers higher risk of metabolic diseases such as diabetes and ischemic heart disease and has been observed to be associated with high morbidity and mortality. It is a progressive pathological process for diabetes-induced complications and appears to be multifactorial in origin. Several preclinical, clinical, and epidemiological reports have shown a persistent link between the metabolic syndrome and oxidative stress. There is pronounced imbalance between pro-oxidants and anti-oxidants with increased production of oxidizing molecules, depletion of anti-oxidants, and consequently accumulation of protein and lipid oxidation products in the cell in metabolic syndrome. The increased cellular pro-oxidant activity also results in altered molecular pathways, mitochondrial dysfunction, deregulation in cell cycle control, chromosomal aberrations, inflammation, and overall decreased biological activity as well as impairment of the antioxidant systems. Here, the focus of our review article will be on the formation of oxidative species, the interplay between metabolic syndrome and oxidative stress, and its potential implications in therapeutic approaches.

Downregulation of miR-377 Promotes Oral Squamous Cell Carcinoma Growth and Migration by Targeting HDAC9.

microRNAs are the post-transcriptional regulators implicated in the initiation and progression of various cancer types, including oral squamous cell carcinoma (OSCC). Here, we investigated the role of miR-377 in OSCC tumorigenesis. miR-377 expression was reduced in OSCC samples and cell line (UPCI-SCC-116), and was associated with patient survival. In vitro restoration of miR-377 repressed cell growth, induced apoptosis, and reduced cell migration. We identified HDAC9 as a target of miR-377 and found miR-377 to regulate HDAC9 and its pro-apoptotic target, NR4A1/Nur77. Our findings show that miR-377 targets HDAC9 pathway in OSCC, suggesting that miR-377-HDAC9 axis may provide a novel therapeutic target for OSCC therapy.

MicroRNA-200c modulates DUSP-1 expression in diabetes-induced cardiac hypertrophy.

Mitogen-activated protein kinases (MAPKs) (ERK1/2, JNK, and p38) are upregulated in diabetic cardiomyopathy (DCM). Dual-specific phosphatase-1 (DUSP-1) has been reported to regulate the activity of MAPKs in cardiac hypertrophy; however, the role of DUSP-1 in regulating MAPKs activity in DCM is not known. MicroRNAs have been reported to regulate the expression of several genes in hypertrophied failing hearts. However, little is known about the microRNAs regulating DUSP-1 expression in diabetes-related cardiac hypertrophy. In the present study, we investigated the role of DUSP-1 and miR-200c in diabetes-induced cardiac hypertrophy. DCM was induced in Wistar rats by low-dose Streptozotocin high-fat diet for 12 weeks. Cardiac expression of ERK, p-38, JNK, DUSP-1, miR-200c, and hypertrophy markers (ANP and ß-MHC) was studied in DCM in control rats and in high-glucose (HG)-treated rat neonatal cardiomyocytes. miR-200c inhibition was performed to validate DUSP-1 as target. A significant increase in phosphorylated ERK, p38, and JNK was observed in DCM model and in HG-treated cardiomyocytes (p < 0.05). Expression of DUSP-1 was significantly decreased in diabetes group and in HG-treated cardiomyocytes (p < 0.05). Increased expression of miR-200c was observed in DCM model and in HG-treated cardiomyocytes (p < 0.05). Inhibition of miR-200c induces the expression of the DUSP-1 causing decreased expression of phosphorylated ERK, p38, and JNK and attenuated cardiomyocyte hypertrophy in HG-treated cardiomyocytes. miR-200c plays a role in diabetes-associated cardiac hypertrophy by modulating expression of DUSP-1.

Overexpression of HDAC9 promotes oral squamous cell carcinoma growth, regulates cell cycle progression, and inhibits apoptosis.

Histone deacetylases (HDACs) are a family of deacetylase enzymes that regulate the acetylation state of histones and a variety of other non-histone proteins including key oncogenic and tumor suppressor proteins, which modulates chromatin conformation, leading to regulation of gene expression. HDACs has been grouped into classes I-IV and histone deacetylase 9 (HDAC9) belongs to class IIa which exhibits tissue-specific expression. Recent reports have demonstrated both pro-oncogenic and tumor suppressive role for HDAC9 in different cancers; however, its role in OSCC remains elusive. Here, we investigated the role of HDAC9 in pathogenesis of oral squamous cell carcinoma (OSCC). Our data showed significantly increased mRNA and protein expression of HDAC9 in clinical OSCC samples and UPCI-SCC-116 cells as compared to normal counterpart. Kaplan-Meier analysis showed that the patients with high-level of HDAC9 expression had significantly reduced overall survival than those with low-level of HDAC9 expression (p = 0.034). Knockdown of HDAC9 using siRNA interference suppressed cell proliferation, increased apoptosis, and induced G0/G1 cell cycle arrest in UPCI-SCC-116 cells. Immunofluorescence analysis showed increased nuclear localization of HDAC9 in frozen OSCC sections, and indicative of active HDAC9 that may transcriptionally repress its downstream target genes. Subsequent investigation revealed that overexpression of HDAC9 contributes to OSCC carcinogenesis via targeting a transcription factor, MEF2D, and NR4A1/Nur77, a pro-apoptotic MEF2 target.

miR-30c and miR-181a synergistically modulate p53-p21 pathway in diabetes induced cardiac hypertrophy.

p53-p21 pathway mediates cardiomyocyte hypertrophy and apoptosis and is upregulated in diabetic cardiomyopathy (DbCM). We investigated role of microRNAs in regulating p53-p21 pathway in high glucose (HG)-induced cardiomyocyte hypertrophy and apoptosis. miR-30c and miR-181a were identified to target p53. Cardiac expression of microRNAs was measured in diabetic patients, diabetic rats, and in HG-treated cardiomyocytes. Effect of microRNAs over-expression and inhibition on HG-induced cardiomyocyte hypertrophy and apoptosis was examined. Myocardial expression of p53 and p21 genes was increased and expression of miR-30c and miR-181a was significantly decreased in diabetic patients, DbCM rats, and in HG-treated cardiomyocytes. Luciferase assay confirmed p53 as target of miR-30c and miR-181a. Over-expression of miR-30c or miR-181a decreased expression of p53, p21, ANP, cardiomyocyte cell size, and apoptosis in HG-treated cardiomyocytes. Concurrent over-expression of these microRNAs resulted in greater decrease in cardiomyocyte hypertrophy and apoptosis, suggesting a synergistic effect of these microRNAs. Our results suggest that dysregulation of miR-30c and miR-181a may be involved in upregulation of p53-p21 pathway in DbCM.

Chloride ions in health and disease.

Chloride is a key anion involved in cellular physiology by regulating its homeostasis and rheostatic processes. Changes in cellular Cl- concentration result in differential regulation of cellular functions such as transcription and translation, post-translation modifications, cell cycle and proliferation, cell volume, and pH levels. In intracellular compartments, Cl- modulates the function of lysosomes, mitochondria, endosomes, phagosomes, the nucleus, and the endoplasmic reticulum. In extracellular fluid (ECF), Cl- is present in blood/plasma and interstitial fluid compartments. A reduction in Cl- levels in ECF can result in cell volume contraction. Cl- is the key physiological anion and is a principal compensatory ion for the movement of the major cations such as Na+, K+, and Ca2+. Over the past 25 years, we have increased our understanding of cellular signaling mediated by Cl-, which has helped in understanding the molecular and metabolic changes observed in pathologies with altered Cl- levels. Here, we review the concentration of Cl- in various organs and cellular compartments, ion channels responsible for its transportation, and recent information on its physiological roles.

Synthesis of imine-pyrazolopyrimidinones and their mechanistic interventions on anticancer activity.

Design, synthesis and anticancer activity of a series of imine-pyrazolopyrimidinones is reported for the first time. Compounds 9d, 9n and 9o in the series show encouraging in vitro anticancer activity with low micromolar IC50 values against prostate (PC3) and breast (MCF7) cancer cell lines. Some notions about structure-activity relationships and plausible mechanism of biological activity are presented.

Myocardin ablation in a cardiac-renal rat model.

Cardiorenal syndrome is defined by primary heart failure conditions influencing or leading to renal injury or dysfunction. Dilated cardiomyopathy (DCM) is a major co-existing form of heart failure (HF) with renal diseases. Myocardin (MYOCD), a cardiac-specific co-activator of serum response factor (SRF), is increased in DCM porcine and patient cardiac tissues and plays a crucial role in the pathophysiology of DCM. Inhibiting the increased MYOCD has shown to be partially rescuing the DCM phenotype in porcine model. However, expression levels of MYOCD in the cardiac tissues of the cardiorenal syndromic patients and the effect of inhibiting MYOCD in a cardiorenal syndrome model remains to be explored. Here, we analyzed the expression levels of MYOCD in the DCM patients with and without renal diseases. We also explored, whether cardiac specific silencing of MYOCD expression could ameliorate the cardiac remodeling and improve cardiac function in a renal artery ligated rat model (RAL). We observed an increase in MYOCD levels in the endomyocardial biopsies of DCM patients associated with renal failure compared to DCM alone. Silencing of MYOCD in RAL rats by a cardiac homing peptide conjugated MYOCD siRNA resulted in attenuation of cardiac hypertrophy, fibrosis and restoration of the left ventricular functions. Our data suggest hyper-activation of MYOCD in the pathogenesis of the cardiorenal failure cases. Also, MYOCD silencing showed beneficial effects by rescuing cardiac hypertrophy, fibrosis, size and function in a cardiorenal rat model.

The Big Entity of New RNA World: Long Non-Coding RNAs in Microvascular Complications of Diabetes.

A major part of the genome is known to be transcribed into non-protein coding RNAs (ncRNAs), such as microRNA and long non-coding RNA (lncRNA). The importance of ncRNAs is being increasingly recognized in physiological and pathological processes. lncRNAs are a novel class of ncRNAs that do not code for proteins and are important regulators of gene expression. In the past, these molecules were thought to be transcriptional "noise" with low levels of evolutionary conservation. However, recent studies provide strong evidence indicating that lncRNAs are (i) regulated during various cellular processes, (ii) exhibit cell type-specific expression, (iii) localize to specific organelles, and (iv) associated with human diseases. Emerging evidence indicates an aberrant expression of lncRNAs in diabetes and diabetes-related microvascular complications. In the present review, we discuss the current state of knowledge of lncRNAs, their genesis from genome, and the mechanism of action of individual lncRNAs in the pathogenesis of microvascular complications of diabetes and therapeutic approaches.

Emerging Evidence of Epigenetic Modifications in Vascular Complication of Diabetes.

Genes, dietary, and lifestyle factors have been shown to be important in the pathophysiology of diabetes and associated microvascular complications. Epigenetic modifications, such as DNA methylation, histone acetylation, and post-transcriptional RNA regulation, are being increasingly recognized as important mediators of the complex interplay between genes and the environment. Recent studies suggest that diabetes-induced dysregulation of epigenetic mechanisms resulting in altered gene expression in target cells can lead to diabetes-associated complications, such as diabetic cardiomyopathy, diabetic nephropathy, retinopathy, and so on, which are the major contributors to diabetes-associated morbidity and mortality. Thus, knowledge of dysregulated epigenetic pathways involved in diabetes can provide much needed new drug targets for these diseases. In this review, we constructed our search strategy to highlight the role of DNA methylation, modifications of histones and role of non-coding RNAs (microRNAs and long non-coding RNAs) in vascular complications of diabetes, including cardiomyopathy, nephropathy, and retinopathy.

DUSP-1 gene expression is not regulated by promoter methylation in diabetes-associated cardiac hypertrophy.

BACKGROUND: The exact mechanism causing decreased expression of the dual specific phosphatase-1 ( DUSP-1) gene in diabetes-associated cardiac hypertrophy is not known. DNA promoter methylation is often associated with decreased gene expression in many diseases including cardiovascular diseases. So, we investigated whether epigenetic silencing via promoter methylation is involved in the decreased expression of DUSP-1 in diabetes-associated cardiac hypertrophy. METHODS: Real-time polymerase chain reaction (PCR) and Western blotting confirmed the down regulation of the DUSP-1 gene at transcriptional and translational levels. Bisulfite-converted DNA samples from myocardium of rat model of diabetic cardiomyopathy (DCM), high glucose (HG)-treated neonatal rat cardiomyocytes (NRCMs) and cardiac tissues from archived human myocardial DCM autopsies along with their respective controls were analyzed for methylation in the promoter region of the DUSP-1 gene. RESULTS: We observed no methylation in the promoter regions of the DUSP-1 gene in DCM rat hearts, in HG-treated NRCMs (between -355 bp and -174 bp) and in cardiac tissues from archived human myocardial DCM autopsies (between -274 bp and -73 bp). CONCLUSION: Methylation-mediated silencing of the DUSP-1 promoter does not appear to be associated with reduced expression, indicating the involvement of other factors in specific suppression of DUSP-1 in diabetes-associated cardiac hypertrophy.

miR-30c Mediates Upregulation of Cdc42 and Pak1 in Diabetic Cardiomyopathy.

AIM: Cardiac hypertrophy and myocardial fibrosis significantly contribute to the pathogenesis of diabetic cardiomyopathy (DCM). Altered expression of several genes and their regulation by microRNAs has been reported in hypertrophied failing hearts. This study aims to examine the role of Cdc42, Pak1, and miR-30c in the pathogenesis of cardiac hypertrophy in DCM. METHODS: DCM was induced in Wistar rats by low-dose streptozotocin-high-fat diet for 12 weeks. Cardiac expression of Cdc42, Pak1 and miR-30c, and hypertrophy markers (ANP and ß-MHC) was studied in DCM vs control rats and in high-glucose (HG)-treated H9c2 cardiomyocytes. RESULTS: Diabetic rats showed cardiomyocyte hypertrophy, increased heart-to-body weight ratio, and an increased expression of ANP and ß-MHC. Cardiac expression of Cdc42 and Pak1 genes was increased in diabetic hearts and in HG-treated cardiomyocytes. miR-30c was identified to target Cdc42 and Pak1 genes, and cardiac miR-30c expression was found to be decreased in DCM rats, patients with DCM, and in HG-treated cardiomyocytes. miR-30c overexpression decreased Cdc42 and Pak1 genes and attenuated HG-induced cardiomyocyte hypertrophy, whereas miR-30c inhibition increased Cdc42 and Pak1 gene expression and myocyte hypertrophy in HG-treated cardiomyocytes. CONCLUSION: Downregulation of miR-30c mediates prohypertrophic effects of hyperglycemia in DCM by upregulation of Cdc42 and Pak1 genes.