Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferator-activated receptor (PPARgamma), a ligand-dependent transcription factor, negatively modulates high glucose effects. We postulated that rosiglitazone (RSG), an activator of PPARgamma prevents the upregulation of vascular endothelial growth factor (VEGF) and collagen IV by mesangial cells exposed to high glucose. Primary cultured rat mesangial cells were growth-arrested in 5.6 mM (NG) or 25 mM D-glucose (HG) for up to 48 hours. In HG, PPARgamma mRNA and protein were reduced within 3 h, and enhanced ROS generation, expression of p22(phox), VEGF and collagen IV, and PKC-zeta membrane association were prevented by RSG. In NG, inhibition of PPARgamma caused ROS generation and VEGF expression that were unchanged by RSG. Reduced AMP-activated protein kinase (AMPK) phosphorylation in HG was unchanged with RSG, and VEGF expression was unaffected by AMPK inhibition. Hence, PPARgamma is a negative modulator of HG-induced signaling that acts through PKC-zeta but not AMPK and regulates VEGF and collagen IV expression by mesangial cells.
Exp Diabetes Res 2009
PMID:Rosiglitazone prevents high glucose-induced vascular endothelial growth factor and collagen IV expression in cultured mesangial cells. 1960 56

Salicornia herbacea has been used as a folk medicine for disorders such as constipation, obesity, diabetes, and cancer. Recent studies have shown that S. herbacea has antioxidative, anti-inflammatory, immunomodulatory, antihyperglycemic, and antihyperlipidemic activities. In the present work, we investigated the protective effects of the chlorogenic acid derivative, 3-caffeoyl, 4-dihydrocaffeoyl quinic acid (CDCQ), which was isolated from S. herbacea, against tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity in Hepa1c1c7 cells. Pretreatment of Hepa1c1c7 cells with CDCQ significantly reduced t-BHP-induced generation of ROS, caspase-3 activation, and subsequent cell death. Also, CDCQ up-regulated heme oxygenase-1 (HO-1) expression, which conferred cytoprotection against oxidative injury induced by t-BHP. Moreover, CDCQ-induced nuclear translocation of the transcription factor NF-E2-related factor 2 (Nrf2), which is upstream of CDCQ-induced HO-1 expression, and PI3K/Akt activation, a pathway that is involved in induced Nrf2 nuclear translocation. Taken together, these results suggest that the protective effects of CDCQ against t-BHP-induced hepatotoxicity may be due, at least in part, to its ability to scavenge ROS and to regulate the antioxidant enzyme HO-1 via the PI3K/Akt-Nrf2 signaling pathways.
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PMID:Protective mechanisms of 3-caffeoyl, 4-dihydrocaffeoyl quinic acid from Salicornia herbacea against tert-butyl hydroperoxide-induced oxidative damage. 1964 27

The redox status of the extracellular compartment has only just been elucidated as a mechanism controlling intracellular signal transduction and correlates with aging, diabetes, heart disease and lung fibrosis. In the present paper, we describe a mechanism by which oxidizing extracellular environments, as maintained by the cysteine/cystine (Cys/CySS) redox couple, induce mitochondria-derived ROS (reactive oxygen species) generation and cause the activation of Nrf2 (nuclear factor-erythroid 2-related factor 2), inducing an antioxidant response. NIH 3T3 cells were cultured in medium with extracellular Cys/CySS redox potentials (Eh), ranging from 0 to -150 mV. Cellular and mitochondrial ROS production significantly increased in cells incubated under more oxidizing extracellular conditions (0 and -46 mV). Trx2 (thioredoxin-2) is a mitochondrial-specific oxidoreductase and antioxidant and became oxidized in cells incubated at 0 or -46 mV. MEFs (mouse embryonic fibroblasts) from Trx2-overexpressing transgenic (Trx2 Tg) mice produced less intracellular ROS compared with WT (wild-type) MEFs at the more oxidizing extracellular conditions. Nrf2 activity was increased in WT MEFs at the 0 or -46 mV conditions, but was inhibited in Trx2 Tg MEFs under the same conditions. Furthermore, Nrf2-regulated gene expression was significantly increased in the WT MEFs, but not in the Trx2 Tg MEFs. These results show that the Cys/CySS redox status in the extracellular compartment regulates intracellular ROS generated primarily in the mitochondria, which play an important role in the activation of Nrf2 and up-regulation of antioxidant and detoxification systems.
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PMID:Extracellular redox status regulates Nrf2 activation through mitochondrial reactive oxygen species. 1977 93

Methylglyoxal (MGO) is a non-enzymatic metabolite in the glycolytic pathway and its concentration in blood and tissues is elevated in diabetes and renal failure. MGO induces tissue injuries via ROS; however, the mechanism remains to be clarified. The present study examined the harmful actions of MGO. Human aortic endothelial cells were assessed under real-time fluorescent microscopy with continuous superfusion. Increases in intracellular ROS were measured with fluorescent indicator, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester (DCFH-DA). The addition of MGO rapidly increased the ROS in a dose-dependent manner. The increment of DCF was entirely abolished by pre-treatment with superoxide anion scavenger and membrane-permeable catalase, indicating that MGO induces superoxide production. The increment was completely inhibited by 2-thenoyltrifluoroacetone or carbonyl cyanide 3-chlorophenylhydrazone and partially inhibited by N-methyl-L-arginine. These data suggest that MGO stimulates superoxide production from mitochondria and partially stimulates nitric oxide synthase in human endothelial cells.
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PMID:Methylglyoxal augments intracellular oxidative stress in human aortic endothelial cells. 1988 46

The action of VEGF (vascular endothelial growth factor) is essential to maintain proper endothelial and vascular function. VEGF stimulates virtually all aspects of endothelial function, namely proliferation, migration, permeability and nitric oxide production and release. In addition, the action of VEGF makes the endothelium anti-apoptotic. In turn, the inhibition of VEGF action is associated with endothelial dysfunction. Likewise, endothelial dysfunction can be found in the presence of several cardiovascular risk factors, including diabetes mellitus, hypercholesterolaemia and smoking. As circulating monocytes express functionally active VEGFR-1 (VEGF receptor 1) on their surface, monocytes and the related VEGFR-1-mediated signal transduction cascades have come into focus. The function of monocytes is negatively affected by diabetes mellitus, resulting in monocyte dysfunction. More specifically, a VEGF-related signal transduction defect can be detected in monocytes isolated from diabetic individuals. This reduced monocyte response to VEGF, demonstrated by a reduced chemotactic response, can be regarded as VEGF resistance. It is based on the pre-activation of certain intracellular pathways secondary to the diabetes mellitus-related RAGE (receptor for advanced glycation end-products) activation, ROS (reactive oxygen species) activation and inhibition of PTPs (protein tyrosine phosphatases). This unspecific pre-activation of intracellular pathways represents the molecular basis of VEGF resistance in diabetes mellitus.
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PMID:VEGF resistance as a molecular basis to explain the angiogenesis paradox in diabetes mellitus. 1990 40

In the past few years, a growing interest has been given to the possible antioxidant functions of a natural acid, synthesized in human tissues: alpha-lipoic acid (ALA). Both the oxidized (disulfide) and reduced (dithiol: dihydrolipoic acid, DHLA) forms of ALA show antioxidant properties. ALA administered in the diet accumulates in tissues, and a substantial part is converted to DHLA via a lipoamide dehydrogenase. Commercial ALA is usually a racemic mixture of the R and S forms. Chemical studies have indicated that ALA scavenges hydroxyl radicals, hypochlorous acid, and singlet oxygen. ALA exerts antioxidant effects in biological systems not only through direct ROS quenching but also via transition metal chelation. ALA has been shown to possess a number of beneficial effects both in the prevention and treatment of diabetes in experimental conditions. ALA presents beneficial effects in the management of symptomatic diabetic neuropathy and has been used in this context in Germany for more than 30 years. In cardiovascular disease, dietary supplementation with ALA has been successfully employed in a variety of in vivo models: ischemia-reperfusion, heart failure, and hypertension. More mechanistic and human in vivo studies are needed to determine whether optimizing the dietary intake of ALA can help to decrease cardiovascular diseases. A more complete understanding of cellular biochemical events that influence oxidative damage is required to guide future therapeutic advances.
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PMID:Antioxidant properties of an endogenous thiol: Alpha-lipoic acid, useful in the prevention of cardiovascular diseases. 1999 23

Increased expression of Na(+)/H(+) exchanger (NHE) and Na(+),K(+)-ATPase activity have been demonstrated in diabetic nephropathy and are implicated in the development of hypertension. The aim of this study was to investigate the effect of a synthetic manganese porphyrin SOD mimic and peroxynitrite scavenger, Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin (MnTM-2-PyP) on the expression of NHE and Na(+),K(+)-ATPase activity in the kidneys of streptozotocin (STZ) diabetic rats. MnTM-2-PyP administration (1 mg/kg/day) started immediately after STZ and lasted 2 months. Glucose and glycosylated hemoglobin levels were measured in blood. NHE-1 and NHE-3 isoform expression, Na(+),K(+)-ATPase activity, and markers of ROS/RNS-induced damage were determined in kidney homogenates. Diabetes caused lipid peroxidation, inactivation of aconitase, and increase of nitrotyrosine, which paralleled an increase in NHE-1 and NHE-3 expression and Na(+),K(+)-ATPase activity. MnTM-2-PyP treatment had no effect on blood glucose and glycosylated hemoglobin, but suppressed lipid peroxidation and nitrotyrosine, protected aconitase against inactivation, and reversed the induction of NHE-1 and NHE-3 isoforms. Na(+)/H(+) exchanger is under the control of redox-based cellular transcriptional activity, including members of the SP family of transcription factors. Mn(III) alkylpyridylporphyrins were previously found to inhibit activation of major transcription factors, including SP-1 via scavenging of signaling ROS/RNS. Therefore, our data suggest that, by reducing the levels of ROS/RNS, MnTM-2-PyP might interfere with signaling pathways responsible for NHE up-regulation.
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PMID:Effect of potent redox-modulating manganese porphyrin, MnTM-2-PyP, on the Na(+)/H(+) exchangers NHE-1 and NHE-3 in the diabetic rat. 2000 8

Oxidative stress resulting in excessive generation of ROS is a compelling initiator of DNA damage along with damage to various cellular proteins and other macromolecules. Poly(ADP-ribose) polymerase (PARP) activation in response to DNA damage, stirs an energy-consuming cellular metabolic cycle; culminating into cell death. The present study was designed to determine the effect of combining an antioxidant, Melatonin and a PARP inhibitor, Nicotinamide on the hallmark deficits developing in diabetic neuropathy (DN). Streptozotocin (STZ, 55 mg/kg, i.p.) was administered to induce diabetes. Six weeks post diabetes induction, two week treatment with Melatonin (3 and 10 mg/kg) and Nicotinamide (100 and 300 mg/kg) either alone or in combination was given. Effect of these interventions on the functional, behavioral and biochemical changes caused by hyperglycemia were studied in treated animals. Melatonin and Nicotinamide alone as well as in combination ameliorated the functional deficits along with improvement in pain parameters. The combination also demonstrated an essential reversal of biochemical alterations. Nitrotyrosine and Poly ADP Ribose (PAR) immunopositivity was significantly decreased in sciatic nerve micro-sections of treatment group. The results of this study advocate that simultaneous inhibition of oxidative stress-PARP activation cascade may prove useful for the pharmacotherapy of DN.
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PMID:Functional and biochemical evidence indicating beneficial effect of Melatonin and Nicotinamide alone and in combination in experimental diabetic neuropathy. 2000 37

Patients with type 2 diabetes lose beta cells, but the underlying mechanisms are incompletely understood. Glucose-6-phosphate dehydrogenase (G6PD) is the principal source of the major intracellular reductant, NADPH, which is required by many enzymes, including enzymes of the antioxidant pathway. Previous work from our laboratory has shown that high glucose impairs G6PD activity in endothelial and kidney cells, which leads to decreased cell survival. Pancreatic beta cells are highly sensitive to increased ROS. This study aimed to determine whether G6PD and NADPH play central roles in beta-cell survival. Human and mouse islets, MIN6 cell line, and G6PD deficient mice were studied. High glucose inhibited G6PD expression and activity. Inhibition of G6PD with siRNA led to increased ROS and apoptosis, decreased proliferation, and impaired insulin secretion. High glucose decreased insulin secretion, which was improved by overexpressing G6PD. G6PD-deficient mice had smaller islets and impaired glucose tolerance compared with control mice, which suggests that G6PD deficiency per se leads to beta-cell dysfunction and death. G6PD plays an important role in beta-cell function and survival. High-glucose-mediated decrease in G6PD activity may provide a mechanistic explanation for the gradual loss of beta cells in patients with diabetes.
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PMID:High glucose inhibits glucose-6-phosphate dehydrogenase, leading to increased oxidative stress and beta-cell apoptosis. 2003 14

Type and quantity of ingested dietary fat contribute to the onset and progression of chronic diseases such as diabetes, obesity or arteriosclerosis. Attention is increasingly focussing on effective therapies for these diseases as well as functional foods that impede the development of insulin resistance and obesity. Studies provided evidence showing polyunsaturated fatty acids of the omega-3 and the omega-6 families play beneficial roles in prevention and treatment of diseases as diverse as Alzheimer's disease, cancer and cardiovascular diseases such as myocardial infarction, arrhythmia, atherosclerosis and hypertension. Strongest evidence is derived from in vitro experiments on cultured cells and animal-based studies, while the results from clinical studies are inconclusive. After ingestion, polyunsaturated fatty acids are distributed to cells and enriched in cellular membranes, where they influence cellular metabolism and survival. Polyunsaturated fatty acids are involved in various mitochondrial processes including mitochondrial calcium homeostasis, gene expression, respiratory function, ROS production and mitochondrial apoptosis. Therefore, mitochondria play a central role in the mechanisms underlying the protective effects of polyunsaturated fatty acids. The complex mechanisms involved in the effects of polyunsaturated fatty acid on mitochondrial actions depend on structural properties, cellular uptake, shuttling and metabolism, competition with intracellular stores as well as inherent properties of fatty acid metabolites. This review will summarize recent findings on the effects of various types of polyunsaturated fatty acids on mitochondria.
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PMID:Effects of dietary polyunsaturated fatty acids on mitochondria. 2004 12


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