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

The glitazones (or thiazolidinediones) are synthetic compounds used in type-2 diabetes, but they also have broad antiproliferative and anti-inflammatory properties still not well understood. We described previously the apoptotic effects of glitazones on astroglioma cells ( J Biol Chem 279: 8976-8985, 2004 ). At certain concentrations, we found a selective lethality on glioma cells versus astrocytes that was dependent on a rapid production of reactive oxygen species (ROS) and seemed unrelated to the receptor peroxisome proliferator activated receptor-gamma. The present study was aimed at characterizing the oxygen derivatives induced by ciglitazone, rosiglitazone, and pioglitazone in C6 glioma cells and to investigate their intracellular source. We examined the interaction of ROS with nitric oxide (NO) and its consequences for glioma cell survival. Fluorescence microscopy and flow cytometry showed that glitazones induced superoxide anion, peroxynitrite, and hydrogen peroxide, with ciglitazone being the most active. ROS production was completely prevented by uncoupling of the electron transport chain and by removal of glucose as an energy substrate, whereas it was unaffected by inhibition of NADPH-oxidase and xanthine-oxidase. Moreover, glitazones inhibited state 3 respiration in permeabilized cells, and experiments with mitochondrial inhibitors suggested that complex I was the likely target of glitazones. Therefore, these results point to the mitochondrial electron transport chain as the source of glitazone-induced ROS in C6 cells. Glitazones also depolarized mitochondria and reduced mitochondrial pH. NO synthase inhibitors revealed that superoxide anion combines with NO to yield peroxynitrite and that the latter contributes to the cytotoxicity of glitazones in astroglioma cells. Future antitumoral strategies may take advantage of these findings.
 ...
PMID:Glitazones induce astroglioma cell death by releasing reactive oxygen species from mitochondria: modulation of cytotoxicity by nitric oxide. 1750 46

Endothelial dysfunction is universal in diabetes, being intimately involved with the development of cardiovascular disease. The pathogenesis of endothelial dysfunction in diabetes is complex. It is initially related to the effects of fatty acids and insulin resistance on 'uncoupling' of both endothelial nitric oxide synthase activity and mitochondrial function. Oxidative stress activates protein kinase C (PKC), polyol, hexosamine and nuclear factor kappa B pathways, thereby aggravating endothelial dysfunction. Improvements in endothelial function in the peripheral circulation in diabetes have been demonstrated with monotherapies, including statins, fibrates, angiotensin-converting enzyme (ACE) inhibitors, metformin and fish oils. These observations are supported by large clinical end point trials. Other studies show benefits with certain antioxidants, L-arginine, folate, PKC-inhibitors, peroxisome proliferator activated receptor (PPAR)-alpha and -gamma agonists and phosphodiesterase (PDE-5) inhibitors. However, the benefits of these agents remain to be shown in clinical end point trials. Combination treatments, for example, statins plus ACE inhibitors and statins plus fibrates, have also been demonstrated to have additive benefits on endothelial function in diabetes, but there are no clinical outcome data to date. Measurement of endothelial dysfunction in cardiovascular research can provide fresh opportunities for exploring the mechanism of benefit of new therapeutic regimens and for planning and designing large clinical trials.
 ...
PMID:Therapeutic regulation of endothelial dysfunction in type 2 diabetes mellitus. 1765 40

Non-alcoholic fatty liver disease (NAFLD) is associated with diabetes, obesity and insulin resistance. The pathogenesis of NAFLD is complex, but modulation of the activities of transcription factors that regulate hepatic lipid and glucose homeostasis may be a key to treating NAFLD. An example of a key transcription factor regulating hepatic lipid metabolism is sterol regulatory element binding proteins (SREBPs), and in this review we present evidence supporting a key role for SREBPs in NAFLD. Currently, the only effective treatment for NAFLD is caloric restriction and peroxisome proliferator activated receptor (PPAR-gamma) agonists. We suggest that further studies are urgently needed to evaluate modulation of SREBP activity as a potential new treatment for NAFLD.
 ...
PMID:Modulation of sterol regulatory element binding proteins (SREBPs) as potential treatments for non-alcoholic fatty liver disease (NAFLD). 1782 87

Obesity is a complex, multifactorial chronic disease frequently associated with cardiovascular risks, hypertriglyceridemia, low high-density lipoprotein-cholesterol, high blood pressure, and the insulin resistance that appears to be central to the pathogenesis of Type II diabetes. Plasminogen activator inhibitor-1 expression induced in differentiating adipose tissue, but its role in adipogenesis and obesity is poorly understood. Circulating plasminogen activator inhibitor-1 levels are elevated at an early stage of impaired glucose tolerance, resulting in diabetes and metabolic syndrome. Plasminogen activator inhibitor-1 levels are also significantly elevated in the plasma of obese individuals and in adipose tissues of obese mice and humans. Some investigators proposed that the -675 4G/5G polymorphism in plasminogen activator inhibitor-1 promoter caused overexpression of this gene and predisposed carriers to obesity. In this study, we investigated the role of -675 4G/5G polymorphism in plasminogen activator inhibitor-1 promoter in the expression of this gene and the contribution of plasminogen activator inhibitor-1 to adipogenesis. Using a dual-luciferase promoter assay, we determined that the -675 4G/5G polymorphism contributes significantly to overexpression of plasminogen activator inhibitor-1 in the course of adipogenesis. The antidiabetic agents troglitazone and ciglitazone inhibited reporter gene expression driven by wild-type and -675 4G/5G mutant promoter, as well as the expression of endogenous plasminogen activator inhibitor-1, indicating that suppression of plasminogen activator inhibitor-1 expression may contribute to antidiabetic effects of these agents. The results indicate that absence of plasminogen activator inhibitor-1 in adipocytes may protect the cells against insulin resistance by promoting glucose uptake and adipocyte differentiation via a decrease in the peroxisome proliferator activated receptor-gamma expression that modulates the adipocyte differentiation.
 ...
PMID:The effect of plasminogen activator inhibitor-1 -675 4G/5G polymorphism on PAI-1 gene expression and adipocyte differentiation. 1816 May 87

This study isolated agonists of peroxisome proliferator activated receptors (PPARs) from the green algae Chlorella sorokiniana, using a bioassay-guided purification strategy. PPARs are widely recognized as the molecular drug targets for many diseases including hyperglycemia, diabetes, obesity and cancer. Two independent bioassays were developed. The first is the scintillation proximity assay, a ligand binding assay. The other is the cell-based transcriptional activation assay which uses the Dual-Luciferase reporter system as the reporter gene under the control of the PPAR response element. Using these two assays, a PPARgamma-active fraction, CE 3-3, was obtained from C. sorokiniana extracts, which was also able to activate PPARalphamediated gene expression. To elucidate the active ingredients in the CE 3-3 fraction, GC-MS analysis was employed. The results showed that the CE 3-3 fraction consisted of at least ten fatty acids (FAs). The bioactivities of several of the individual FAs were evaluated for their PPARgamma activity and the results showed that linolenic acid and linoleic acid were the most potent FAs tested. Our studies indicate that Chlorella sorokiniana could have potential health benefits through the dual activation of PPARalpha/gamma via its unique FA constituents.
 ...
PMID:Bioassay-guided purification and identification of PPARalpha/gamma agonists from Chlorella sorokiniana. 1839 4

Before the discovery of peroxisome proliferator activated receptors (PPARs), it was well known that certain drugs considered as classical PPAR-alpha agonists induced hepatocarcinoma or peroxisome proliferation in rodents. These drugs were derivatives of fibric acid, and they included clofibrate, bezafibrate, and fenofibrate. However, such toxicity has never been observed in human patients treated with these hypolipidemic drugs. Thiazolidinediones are a new class of PPAR activators showing greater specificity for the gamma isoform of PPARs. These drugs are used as insulin sensitizers in the treatment of type II diabetes. In addition, they have been shown to induce cell differentiation or apoptosis in various experimental models of cancer. PPAR-alpha ligands have also been shown to induce cancer cell differentiation and, paradoxically, PPAR-gamma drug activators have been reported to act as carcinogens. The confusing picture that emerges from these data is further complicated by the series of intriguing side effects observed following administration of pharmacological PPAR ligands (rhabdomyolysis, liver and heart toxicity, anemia, leucopenia). These side effects cannot be easily explained by simple interactions between the drug and nuclear receptors. Rather, these side effects seem to indicate that the ligands have biological activity independent of the nuclear receptors. Considering the emerging role of mitochondria in cancer and the potential metabolic connections between this organelle and PPAR physiology, characterization of the reciprocal influences is fundamental not only for a better understanding of cancer biology, but also for more defined pharmacotoxicological profiles of drugs that modulate PPARs.
PPAR Res 2008
PMID:Mitochondria, PPARs, and Cancer: Is Receptor-Independent Action of PPAR Agonists a Key? 1864 11

Despite medical advice, 20-30% of female smokers continue to smoke during pregnancy. Epidemiological studies have associated maternal smoking with increased risk of obesity and type-2 diabetes in the offspring. In the present study, we investigated the impact of prenatal nicotine exposure (3 mg/kg in Sprague Dawley rats via osmotic Alzet minipumps) on the early endocrine pancreas and adipose tissue development in rat pups before weaning. Body weight, fat deposition, food intake and food efficiency, cold tolerance, spontaneous physical activity, glucose utilization, and insulin sensitivity were also examined at adulthood. Prenatal nicotine exposure led to a decrease in endocrine pancreatic islet size and number at 7 d of life (postnatal d 7), which corroborates with a decrease in gene expression of specific transcription factors such as pancreatic and duodenal homeobox 1, Pax-6, Nkx6.1, and of hormones such as insulin and glucagon. The prenatal nicotine exposure also led to an increase in epididymal white adipose tissue weight at weaning (postnatal d 21), and marked hypertrophy of adipocytes, with increased gene expression of proadipogenic transcription factors such as CAAT-enhancer-binding protein-alpha, peroxisome proliferator activated receptor-gamma, and sterol regulatory element binding protein-1C. These early tissue alterations led to significant metabolic consequences, as shown by increased body weight and fat deposition, increased food efficiency on high-fat diet, cold intolerance, reduced physical activity, and glucose intolerance combined with insulin resistance observed at adulthood. These results prove a direct association between fetal nicotine exposure and offspring metabolic syndrome with early signs of dysregulations of adipose tissue and pancreatic development.
 ...
PMID:Prenatal nicotine exposure alters early pancreatic islet and adipose tissue development with consequences on the control of body weight and glucose metabolism later in life. 1868 84

Thiazolidinediones increase tissue insulin sensitivity and are protective against worsening of nephropathy and hypertension in diabetes. Mechanisms underlying protection at the renal level likely involve a variety of unknown changes in gene expression. We examined kidney gene expression in obese and lean Zucker rats in response to rosiglitazone (Avandia), a peroxisome proliferator activated receptor (gamma-subtype) agonist. Lean and obese Zucker rats were treated with either control chow or chow with added rosiglitazone (3 mg/kg x bw) for 12 weeks (n = 3/group). Total kidney mRNA expression was evaluated using the Affymetrix Rat Genome 230 2.0 GeneChip. 903 probe sets were significantly (P < 0.05) altered with at least 1.5-fold changes between groups. In untreated obese rats, 300 probe sets were increased and 244 decreased, relative to lean. Increased genes included the beta-subunit of the epithelial sodium channel (ENaC), the thiazide-sensitive Na-Cl cotransporter, and aquaporin 3. Decreased genes included angiotensin converting enzyme, type 1 (ACE1). FatiGO analysis showed that the highest number of altered genes between lean and obese belonged to the categories: ion binding, hydrolase activity, and protein binding. RGZ increased expression of uncoupling protein 1 (UCP1), CD36, and fatty acid binding protein 4 (FAbp4) in both lean and obese rats. In obese rats, 33 genes were normalized by RGZ (no longer different from lean) including ACE1, fatty acid synthase (Fasn), and stearoyl-coenzyme A desaturase (SCD1). Ingenuity Pathways System analysis of genes upregulated by RGZ in obese rats revealed two major nodes affected: PPAR-gamma and tumor necrosis factor alpha (TNF-alpha).
Exp Clin Endocrinol Diabetes 2008 Jun
PMID:Chronic rosiglitazone therapy normalizes expression of ACE1, SCD1 and other genes in the kidney of obese Zucker rats as determined by microarray analysis. 1870 Feb 76

The insulin-sensitizing drug pioglitazone has been reported to be protective against myocardial infarction. However, its precise mechanism is unclear. Rabbits underwent 30 min of coronary occlusion followed by 48 h of reperfusion. Rabbits were assigned randomly to nine groups (n = 10 in each): the control group (fed a normal diet), pioglitazone group (fed diets containing 1 mg.kg(-1).day(-1) pioglitazone), pioglitazone + 5-hydroxydecanoic acid (HD) group [fed the pioglitazone diet + 5 mg/kg iv 5-HD, a mitochondrial ATP-sensitive K(+) (K(ATP)) channel blocker], pioglitazone + GW9662 group [fed the pioglitazone diet + 2 mg/kg iv GW9662, a peroxisome proliferator activated receptor (PPAR)-gamma antagonist], GW9662 group (fed a normal diet + iv GW9662), pioglitazone + wortmannin group [fed the pioglitazone diet + 0.6 mg/kg iv wortmannin, a phosphatidylinositol (PI)3-kinase inhibitor], wortmannin group (fed a normal diet + iv wortmannin), pioglitazone + nitro-l-arginine methyl ester (l-NAME) group [fed the pioglitazone diet + 10 mg/kg iv l-NAME, a nitric oxide synthase (NOS) inhibitor], and l-NAME group (fed a normal diet + iv l-NAME). All groups were fed the diets for 7 days. The risk area and nonrisk area of the left ventricle (LV) were separated by Evans blue dye, and the infarct area was determined by triphenyltetrazolium chloride staining. The infarct size was calculated as a percentage of the LV risk area. Western blotting was performed to assess levels of Akt and phospho-Akt and phospho-endothelial NOS (eNOS) in the myocardium following reperfusion. The infarct size was significantly smaller in the pioglitazone group (21 +/- 2%) than in the control group (43 +/- 3%). This effect was abolished by GW9662 (42 +/- 3%), wortmannin (40 +/- 3%), or l-NAME (42 +/- 7%) but not by 5-HD (24 +/- 5%). Western blotting showed higher levels of phospho-Akt and phospho-eNOS in the pioglitazone group. Pioglitazone reduces the myocardial infarct size via activation of PPAR-gamma, PI3-kinase, Akt, and eNOS pathways, but not via opening the mitochondrial K(ATP) channel. Pioglitazone may be a novel strategy for the treatment of diabetes mellitus with coronary artery disease.
 ...
PMID:Antidiabetic drug pioglitazone protects the heart via activation of PPAR-gamma receptors, PI3-kinase, Akt, and eNOS pathway in a rabbit model of myocardial infarction. 1928 54

Dementia is one of the most important health problems in the aging populations. The most frequent cause of it is Alzheimer's disease (AD) which is characterized by intracellular neuro-fibrillary tangles (NFT) and the extracellular senile plaques. The NFTs are mainly formed by the hyperphosphorylated microtubule-binding protein, the tau, while the senile plaques are composed of beta-amyloid protein cleaved from the amyloid precursor protein (APP) by the beta- and gamma-secretases. The pharmacotherapy of AD consists of symptomatic and disease-modifying therapies. The most frequently used therapeutic agents are the nootropic drugs supported by personal rather evidence based experiences. The leading-edge therapy of AD at present is the inhibition of the acetylcholine-esterase enzyme (AChEI) with mainly cognitive symptomatic and weak disease-modifying effects; they are licensed in the mild and middle stages of AD (MMSE 26-10), but their effect is proved in the severe stage of the disease and they are effective in the management of the neuropsychiatric symptoms too. Memantine (which is an inhibitor of the N-metil-D-aspartate receptor) is used in the middle and severe stages of AD and it can be effectively combined with AChEIs. The future therapy of AD will possibly be a "causative" therapy. The most frequent directions are therapies aiming to decrease the production or the deposition of beta-amyloid peptide. The active vaccination study of AN-1792 was terminated because of immunological side-effects, but several active and passive immunisation therapies are in development nowadays. It is also possible to inhibit the aggregation of the beta-amyloid peptide with peptide fragments or with Cu2+ and Zn2+ ion chelators. A promising direction is the inhibition of the enzymes responsible for the production of the beta-amyloid peptide: beta-secretase inhibitors with low molecular weight and penetrability through the blood-brain barrier are developed while the inhibitors of the gamma-secretase (some of them are the derivatives of the non-steroid anti-inflammatory drug ibuprofen) are tested in phase III trials. The inhibition of NFT formation might be promising too and inhibitors of the enzymes responsible for the hyperphosphorylation of the tau (like the glycogen synthase kinase-3) are in develo ment. Several other therapeutic methods are studied. NSAIDs and statins are useful in the prevention of the disease but they are failed in symptomatic treatment. There are promising studies in few patients using nerve growth factor therapy and some studies proved that peroxisome proliferator activated receptor (PPAR) agonist rosiglitazone (which is used to the treat diabetes mellitus) is effective in AD. The presently modest therapeutic interventions of AD will explode in the near future and together with the improved diagnostics of the disease they will cause further specialization with increased treatment and caring costs amplified by the ever growing number of the patients. This means that AD is and will be one of the most important diseases for the health care systems.
 ...
PMID:[Therapy of Alzheimer disease]. 1973 16


<< Previous 1 2 3 4 5 6 7 Next >>