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)

Group VI phospholipase A2 (PLA2) is a family of acyl hydrolases that targets the sn-2 fatty acid on the glycerophospholipid (GPL) backbone. These enzymes are grouped together based on structural homologies and catalytic activities that are independent of calcium and hence are also called the iPLA(2)s. Although the best characterized of these enzymes, iPLA2beta and iPLA2gamma, have long been proposed as homeostatic enzymes involved in basal GPL metabolism, recent studies indicate roles for these enzymes in biomedically relevant processes as well. For example, iPLA2 modulates calcium homeostasis by promoting replenishment of intracellular calcium stores. This function is likely of importance in the pathogenesis of Duchenne muscular dystrophy and potentially allergy as well. iPLA2 has a variety of roles in bacterial pathogenesis and the host response against bacterial and fungal infections. These characteristics suggest that the enzyme as a potential target to control infectious diseases. iPLA2 is linked to both proliferation and chemotherapy-induced apoptosis of tumor cells. As such, the enzyme is a potential target for cancer chemotherapy. Recent studies indicate essential roles for iPLA2 in glucose homeostasis, maintenance of energy balance, adipocyte development, and hepatic lipogenesis. Thus, the enzyme is an attractive target for drugs to control type II diabetes, fatty liver disease, and other manifestations of the metabolic syndrome. Several recent studies have associated iPLA2 inactivation with neurodegenerative diseases, suggesting the possibility that products of the iPLA2 reaction as potential treatments for these disorders. Together, these observations suggest iPLA2 as a novel and important target for drug development. However given the ubiquitous expression of the enzyme and its roles in basal GPL metabolism, drug strategies targeting iPLA2 must exhibit exquisite selectivity to avoid undesired side effects. Furthermore, the cell-specific nature of many iPLA2 functions may present another challenge in the design and implementation of drugs targeted to the enzyme.
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PMID:Group VI phospholipases A2: homeostatic phospholipases with significant potential as targets for novel therapeutics. 1869 Oct 15

Pancreatic phospholipase A2 (phospholipase A2 group 1B, G1B) belongs to the superfamily of secreted phospholipase A2 (PLA2) enzymes. G1B has been proposed to be a potential target for diseases such as hypertension, obesity, and diabetes. Human pancreatic prophospholipase A2 (pro-hG1B) is activated by cleavage of the first seven-residue propeptide (phospholipase A2 propeptide, PROP). However, questions still remain on the mode of action for pro-hG1B. In this work, we expressed pro-hG1B in Pichia pastoris and determined the crystal structure at 1.55-A resolution. The x-ray structure demonstrates that pro-hG1B forms a trimer. In addition, PROP occupies the catalytic cavity and can be self-cleaved at 37 degrees C. A new membrane-bound surface and activation mechanism are proposed based on the trimeric model of pro-hG1B. We also propose a new autoproteolytic mechanism for pro-hG1B by the reaction triad Asp49-Arg0-Ser(-2) that is similar to the serine protease catalytic triad.
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PMID:Structural insight into the activation mechanism of human pancreatic prophospholipase A2. 1929 24

This study investigated the correlation of sPLA2 (secretory phospholipase A2) activity with the atheromatosis extent in subjects with coronary artery disease (CAD) undergoing coronary angiography. We analyzed 123 patients, including 35 subjects with angiographically normal coronary arteries (controls), 31 with mild/moderate atheromatosis (stenosis of 30-70% of the luminal diameter in one or more coronary arteries) and 57 with severe atheromatosis (>70% stenosis). Plasma sPLA2 activity was significantly higher in subjects with severe [127.7 U/ml (102.3-162.7); p < 0.0001] and mild/moderate [112.0 U/ml (100.6-146.9); p < 0.0001] atheromatosis than in controls [19.8 U/ml (15.1-32.1)]. In a multiple logistic regression model, adjusted for age, gender, body mass index, tabagism, hypertension, sedentarism, family history for coronary artery disease, diabetes mellitus, total cholesterol, HDLc, LDLc, triglycerides, high sensitivity C-reactive protein and phospholipase A2, only sPLA2 was observed to be independently associated with severe CAD (>70% of stenosis) (p < 0.0001).
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PMID:Secretory phospholipase A2 in patients with coronary artery disease. 1944 49

Diabetes mellitus is associated with vascular complications including an impairment of vascular function and alterations in the reactivity of blood vessels to vasoactive hormones. However, the signaling mechanisms leading to vascular dysfunction in diabetes are not fully understood. This microarray-based study was designed to identify differential gene expression between the normal and diabetic mesenteric vasculature and to investigate the effect of inhibiting epidermal growth factor receptor (EGFR) signaling on global gene expression in the mesenteric bed of streptozotocin (STZ)-induced diabetic rats. Transcriptome analysis was performed in triplicate using oligonucleotide microarrays housing 10,000 rat genes on the mesenteric bed of normal, diabetic, and diabetic rats treated with AG1478, a selective inhibitor of EGFR. Four weeks of diabetes led to a profound alteration in gene expression within the mesenteric bed with 1167 of the 3074 annotated genes being up-regulated and 141 genes down-regulated by at least 2-fold. The up-regulated gene ontologies included receptor tyrosine kinases, G-protein coupled receptors and ion channel activity. In particular, significant overexpressions of colipase, phospholipase A2, carboxypeptidases, and receptor tyrosine kinases such as EGFR, erbB2 and fibroblast growth factor receptor were observed in diabetes mesenteric vasculature. A 4-week intraperitoneal treatment of diabetic animals with AG1478 (1.2 mg/kg/alt diem) beginning on the same day as STZ injection prevented up-regulation of the majority (approximately 95%) of the genes associated with STZ diabetes including those apparently "unrelated" to the known EGFR pathway without correction of hyperglycemia. These results suggest that activation of EGFR signaling is a key initiating step that leads to induction of multiple signaling pathways in the development of diabetes-induced vascular dysfunction. Thus, therapeutic targeting of EGFR may represent a novel strategy for the prevention and/or treatment of vascular dysfunction in diabetes.
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PMID:Early inhibition of EGFR signaling prevents diabetes-induced up-regulation of multiple gene pathways in the mesenteric vasculature. 1957 3

TZDs (thiazolidinediones) are prescribed as anti-Type II diabetes drugs, but little is known regarding whether TZDs regulate the expression of sPLA2 (secretory phospholipase A2) in macrophages. We have investigated the effects of pioglitazone on LPS (lipopolysaccharide)-induced production of TNF-alpha (tumour necrosis factor alpha), sPLA2-V and -X (groups V and X sPLA2) in RAW 264.7 macrophages. TNF-alpha, sPLA2-V and -X mRNA and protein expression were determined by RT-PCR (reverse transcriptase-PCR) and Western blot analysis, respectively. The activity of NF-kappaB (nuclear factor kappaB) was determined by Western blot and confocal microscopy. LPS induced TNF-alpha, sPLA2-V and sPLA2-X mRNA and protein expression. Pretreatment with 10 mumol/l pioglitazone significantly suppressed LPS-induced TNF-alpha, sPLA2-V and sPLA2-X mRNA and protein expression. LPS induced NF-kappaB expression and translocation in the nucleus, but the inductive effects were inhibited by pioglitazone. Our findings indicate that pioglitazone inhibits production of inflammatory factors induced by LPS in murine macrophage cells by inactivating NF-kappaB. Pioglitazone appears to play an anti-inflammatory role in the atherosclerotic process.
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PMID:Pioglitazone suppresses the lipopolysaccharide-induced production of inflammatory factors in mouse macrophages by inactivating NF-kappaB. 1994 50

To combat cardiovascular disease (CVD), physicians and allied health care professionals often focus on modifying conventional risk factors such as cigarette smoking, hypertension, hypercholesterolemia, and diabetes. However, a recent review of published research demonstrated that 75% to 90% of coronary artery disease (CAD) incidence is explained by these risk factors, either alone or in combination. This has stimulated a vigorous search for other correctable risk factors (ie, to explain the remaining incidence [10%-25%]), including genetic anomalies, markers of inflammation (C-reactive protein, lipoprotein-associated phospholipase A2), and specific lipid/lipoprotein particles to enhance risk stratification. Nevertheless, an escalating body of research provides strong evidence for the adverse effects of psychosocial factors in the development of CVD and in the prognosis of patients with CAD.
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PMID:Impact of psychosocial risk factors on the heart: changing paradigms and perceptions. 2004 26

Type 2 diabetes is a metabolic disease, which frequency increases substantially with age. Oxidative stress as a result of production and deactivation of free radicals unbalance, may play an important role in a complex pathogenesis of disease. Free radicals are by-products of metabolism, which in regard to their chemical structure, readily react with DNA, lipids, proteins and carbohydrates and cause changes in their structure and function. Antioxidant enzyme system and small molecule antioxidants protect organism against harmful effect of free radicals. In accordance to free radical theory of aging, antioxidant enzymes and molecules activity decrease with age. At the same time, quantity of disadvantageous changes caused by reactive oxygen species (RFT) increase. Disturbance in the prooxidant-antioxidant balance causes organism senescence and development of age-related diseases including diabetes mellitus. Hyperglycemia is an additional factor which can escalate systemic oxidative stress in diabetes mellitus. Elevated concentration of glucose increases generation of reactive oxygen species and accumulation of oxidative modified macromolecules as a result of accelerated activation of a few independent molecular pathways such as autooxidation of monosacharides, non-enzymatic glycosylation, activation of protein kinase C, phospholipase A2 and polyol pathway. Moreover aging is associated with decrease of melatonin concentration, which leads to physiological dysfunctions including depressed antioxidant defense mechanisms. Antioxidant properties of melatonin, which protects macromolecules, especially DNA, from harmful effects of RFT, are particularly important in aspect of free radical theory of aging.
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PMID:[Melatonin and oxidative stress in elderly patients with type 2 diabetes]. 2056 8

The neuroendocrine theory of aging identified a cluster of conditions (hypertension, obesity, dyslipidemia, diabetes type 2, menopause, late onset depression, vascular cognitive impairment, impairment of immune defense, and some forms of cancer, e.g., breast and prostate) as age-associated neuroendocrine disorders (AAND). Obesity, dyslipidemia, hypertension, and type 2 diabetes were later described as metabolic syndromes (MetS). Chronic inflammation is currently considered as a common feature of MetS/AAND. One of the mechanisms by which chronic inflammation might trigger and/or maintain the development of MetS/AAND is transcriptional induction of indoleamine 2,3-dioxygenase (IDO), rate-limiting enzyme of tryptophan (TRY)-kynurenine (KYN) pathway, by pro-inflammatory cytokines (PIC). Activation of IDO shifts TRY metabolism from serotonin synthesis to formation of "kynurenines." Diminished serotonin production is associated with mental depression while increased formation of kynurenines might contribute to development of MetS/AAND via their apoptotic, neurotoxic, and pro-oxidative effects, and upregulation of inducible nitric oxide synthase, phospholipase A2, arachidonic acid, prostaglandin, 5-lipoxygenase, and leukotriene cascade. The combined presence of high producers of alleles of polymorphic PIC genes (e.g., interferon-gamma and tumor necrosis factor alpha) might account for the genetic predisposition to high levels of PIC production, leading to "superinduction" of IDO. The other rate-limiting enzyme of the TRY-KYN pathway, TRY 2,3-dioxygenase, is activated by substrate (TRY) and cortisol. Therefore, KYN-TRY metabolism might be the meeting point for gene-environment interaction and a new target for prevention and treatment of MetS/AAND.
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PMID:Metabolic syndrome, age-associated neuroendocrine disorders, and dysregulation of tryptophan-kynurenine metabolism. 2063 4

This review of literature and our data suggests that up-regulated production of interferon-gamma (IFNG) in periphery and brain triggers a merger of tryptophan (TRY)-kynurenine (KYN) and guanine-tetrahydrobiopterin (BH4) metabolic pathways into inflammation cascade involved in aging and aging-associated medical and psychiatric disorders (AAMPD) (metabolic syndrome, depression, vascular cognitive impairment). IFNG-inducible KYN/pteridines inflammation cascade is characterized by up-regulation of nitric oxide synthase (NOS) activity (induced by KYN) and decreased formation of NOS cofactor, BH4, that results in uncoupling of NOS that shifting arginine from NO to superoxide anion production. Superoxide anion and free radicals among KYN derivatives trigger phospholipase A2-arachidonic acid cascade associated with AAMPD. IFNG-induced up-regulation of indoleamine 2,3-dioxygenase (IDO), rate-limiting enzyme of TRY-KYN pathway, decreases TRY conversion into serotonin (substrate of antidepressant effect) and increases production of KYN associated with diabetes [xanthurenic acid (XA)], anxiety (KYN), psychoses and cognitive impairment (kynurenic acid). IFNG-inducible KYN/pteridines inflammation cascade is impacted by IFNG (+874) T/A genotypes, encoding cytokine production. In addition to literature data on KYN/TRY ratio (IDO activity index), we observe neopterin levels (index of activity of rate-limiting enzyme of guanine-BH4 pathway) to be higher in carriers of high (T) than of low (A) producers alleles; and to correlate with AAMPD markers (e.g., insulin resistance, body mass index, mortality risk), and with IFN-alpha-induced depression in hepatitis C patients. IFNG-inducible cascade is influenced by environmental factors (e.g., vitamin B6 deficiency increases XA formation) and by pharmacological agents; and might offer new approaches for anti-aging and anti-AAMPD interventions.
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PMID:Interferon-gamma-inducible kynurenines/pteridines inflammation cascade: implications for aging and aging-associated psychiatric and medical disorders. 2081 99

Secretory phospholipase A2 (sPLA2) is an enzyme that plays an important role in the pathogenesis of atherosclerosis and of adverse cardiovascular events. It is currently the target of emerging therapeutic agents. Our study was designed to investigate the effect of aggressive lowering of low-density lipoprotein (LDL) cholesterol with ezetimibe and atorvastatin on sPLA2 activity. We randomized 100 patients with stable coronary artery disease (CAD) or CAD equivalent (diabetes, stroke, or peripheral vascular disease) to receive ezetimibe 10 mg/day in association with atorvastatin 40 mg/day (combination therapy group) versus atorvastatin 40 mg/day and placebo (monotherapy group). Patients on statin therapy before inclusion were allowed to enter the study as long as the potency of the statin was lower than atorvastatin 40 mg/day. Lipid profile, high-sensitivity C-reactive protein (hs-CRP), and sPLA activity were measured at baseline and after 8 weeks of therapy. The decrease in LDL cholesterol was more significant in the combination therapy group, but the decrease in hs-CRP was similar. sPLA2 activity significantly decreased in the ezetimibe/atorvastatin group from 29 U/ml (interquartile range 23 to 35) to 26 U/ml (23 to 29, p = 0.001) but remained similar in the placebo/atorvastatin group (23 U/ml, 19 to 32, vs 22 U/ml, 19 to 28, p = NS). In a multivariate stepwise linear regression model, change in sPLA2 correlated with change in hs-CRP (p <0.001), baseline LDL cholesterol level (p = 0.001), body mass index (p = 0.003), diabetes mellitus (p = 0.04) and combination therapy with ezetimibe/atorvastatin (p = 0.05). In conclusion, this study demonstrates that coadministration of ezetimibe and atorvastatin decreases sPLA2 activity.
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PMID:Comparison of the effects of combination atorvastatin (40 mg) + ezetimibe (10 mg) versus atorvastatin (40 mg) alone on secretory phospholipase A2 activity in patients with stable coronary artery disease or coronary artery disease equivalent. 2143 29


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