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)

The membrane protein plasma cell differentiation antigen 1 (PC-1) has been purified as an inhibitor of insulin receptor tyrosine kinase activity and has been implicated in the pathogenesis of NIDDM. However, we show here that PC-1 is a general protein kinase inhibitor in vitro and that this inhibition results from the hydrolysis of ATP by the intrinsic nucleotide pyrophosphatase activity of PC-1. Thus, the inhibition diminished with increasing ATP concentrations, and it was nullified when the ATP concentration was kept constant with a regenerating system or when ATP was added repetitively. When care was taken to avoid ATP depletion, PC-1 did not affect the insulin sensitivity of insulin receptor autophosphorylation. We conclude that the reported inhibition of insulin signaling by PC-1 does not result from a direct inhibition of the insulin receptor kinase activity.
Diabetes 1996 Jul
PMID:The inhibition of the insulin receptor by the receptor protein PC-1 is not specific and results from the hydrolysis of ATP. 866 52

A polymorphism in the ecto-nucleotide pyrophosphatase/phosphodiesterase 1 gene (ENPP1) (previously known as PC-1), resulting in an amino acid change from lysine to glutamine at codon 121 (K121Q), is associated with insulin resistance. A small follow-up study of patients with type 1 diabetes and proteinuria found that renal function declines more rapidly in carriers of the Q variant than in noncarriers. To examine this finding further, we conducted a large case-control study and a family-based study. Genomic DNA was obtained from 659 patients: 307 with normal urinary albumin excretion despite diabetes duration of >15 years (control subjects) and 352 with advanced diabetic nephropathy, of whom 200 had persistent proteinuria and 152 had end-stage renal disease (ESRD). Individuals were genotyped for Q and K variants using a previously described protocol. The frequency of Q variant carriers was 21.5% in control subjects, 31.5% in subjects with proteinuria, and 32.2% in subjects with ESRD (P = 0.012). In a stratified analysis according to duration of diabetes, the risk of early-onset ESRD for carriers of the Q variant was 2.3 times that for noncarriers (95% CI, 1.2-4.6). The Q variant was not associated with late-onset ESRD. Similar findings were obtained in a family-based study. We conclude that carriers of the Q variant of ENPP1 are at increased risk for developing ESRD early in the course of type 1 diabetes.
Diabetes 2002 Apr
PMID:Polymorphism in ecto-nucleotide pyrophosphatase/phosphodiesterase 1 gene (ENPP1/PC-1) and early development of advanced diabetic nephropathy in type 1 diabetes. 1191 43

Ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPPs) have been implicated in bone calcification, type II diabetes, control of purinergic signalling and tumour invasion. The gene for the plasma cell membrane glycoprotein PC-1 in the mouse (Enpp1) has been known since 1970 to exist in two allelic forms, but their structural basis was heretofore unknown. We show that the Enpp1a and Enpp1b alleles differ by only two amino acids, at positions 650 and 679 in the C-terminal nuclease-like domain. Histidine 650 but not arginine 679 forms an essential part of the Enpp1a epitope recognized by monoclonal antibody IR-518. Sequences of LEW and LOU rats and the rat glioma cell line C6 differ from that of the mouse by about 60 amino acids. The LOU and C6 cell line sequences differ by only three amino acids, but differ from the LEW sequence by 10 amino acids. All three rat strains possess the mouse Enpp1b allele at positions 650 and 679. Despite numerous other differences from the mouse, rats immunized with Enpp1a mouse cells have generated monoclonal antibodies specific for the Enpp1a allele, suggesting that amino acids 650 and 679 may be particularly immunogenic. The cytoplasmic tails of the mouse and rat are highly conserved, but are significantly different from human cytoplasmic tails.
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PMID:Structural basis of allotypes of ecto-nucleotide pyrophosphatase/phosphodiesterase (plasma cell membrane glycoprotein PC-1) in the mouse and rat, and analysis of allele-specific xenogeneic antibodies. 1212 Dec 76

Autotaxin (ATX) is a member of the ecto-nucleotide pyrophosphatase/phosphodiesterase (NPP) family and is a lysophospholipase D that cleaves the choline headgroup from lysophosphatidylcholine to generate the bioactive lipid lysophosphatidic acid (LPA). Enhanced expression of ATX and specific receptors for LPA in numerous cancer cell types has created an interest in studying ATX as a potential chemotherapeutic target. Likewise, ATX has been linked to several additional human diseases including multiple sclerosis, diabetes, obesity, neuropathic pain, and Alzheimer's disease. ATX inhibitors reported to date consist of metal ion chelators, lipid-like product analogs, and non-lipid small molecules. In the current research, we examined the pharmacology of the best of our previously reported non-lipid small molecule inhibitors. Here, these six inhibitors were studied utilizing the synthetic fluorescent lysophospholipid substrate FS-3, the nucleotide substrate pNP-TMP and the endogenous substrate LPC (16:0). All six compounds inhibited FS-3 hydrolysis >or=50%, whereas only three inhibited the hydrolysis of pNP-TMP to this degree. None of the six compounds blocked LPC 16:0 hydrolysis within the desired 50% inhibition range. The most potent analog (5, H2L 7905958) displayed an IC(50) of 1.6microM (K(i)=1.9microM, competitive inhibition) with respect to ATX-mediated FS-3 hydrolysis and an IC(50) of 1.2microM (K(i)=K(i)(')=6.5microM, non-competitive inhibition) against ATX-mediated pNP-TMP hydrolysis. All six inhibitors were specific for ATX as they were without affect on two additional lipid preferring NPP isoforms.
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PMID:Characterization of non-lipid autotaxin inhibitors. 2000 24

The increased prevalence of diabetes mellitus has caused a rise in the occurrence of its chronic complications, such as diabetic nephropathy (DN), which is associated with elevated morbidity and mortality. Familial aggregation studies have demonstrated that besides the known environmental risk factors, DN has a major genetic component. Therefore, it is necessary to identify genes associated with risk for or protection against DN. Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) is expressed in several tissues, including the kidneys. Increased levels of ENPP1 expression inhibit tyrosine-kinase activity of the insulin receptor in several cell types, leading to insulin resistance. K121Q polymorphism of the ENPP1 gene seems to be associated with insulin resistance and DN development. The elucidation of genetic factors and their associations will provide better understanding of the pathogenesis of DN and, may consequently, lead to a more effective approach to prevention and treatment.
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PMID:The role of ecto-nucleotide pyrophosphatase/phosphodiesterase 1 in diabetic nephropathy. 2223 69

Body weight is tightly regulated by food intake and energy dissipation, and obesity is related to decreased energy expenditure (EE). Herein, we show that nucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2, autotaxin) is an adipose-derived, secreted enzyme that controls adipose expansion, brown adipose tissue (BAT) function, and EE. In mice, Enpp2 was highly expressed in visceral white adipose tissue and BAT and is downregulated in hypertrophied adipocytes/adipose tissue. Enpp2(+/-) mice and adipocyte-specific Enpp2 knockout mice fed a high-fat diet showed smaller body weight gains and less insulin resistance than control mice fed the same diet. BAT was functionally more active and EE was increased in Enpp2-deficient mice. In humans, ENPP2 expression in subcutaneous fat and ENPP2 levels in serum were reduced in obese subjects. Taken together, our results establish ENPP2 as an adipose-derived, secreted enzyme that regulates adipose obesity and systemic metabolism. They also suggest ENPP2 could be a useful therapeutic target for the treatment of metabolic disease.
Diabetes 2014 Dec
PMID:ENPP2 contributes to adipose tissue expansion and insulin resistance in diet-induced obesity. 2496 10

Vascular calcification is a pathology characterized by the deposition of calcium-phosphate in cardiovascular structures, mainly in the form of hydroxyapatite crystals, resulting in ectopic calcification. It is correlated with increased risk of cardiovascular disease and myocardial infarction in diabetic patients and in those with chronic kidney disease (CKD). Vascular smooth muscle cells are sensitive to changes in inorganic phosphate (Pi) levels. They are able to adapt and modify some of their functions and promote changes which trigger calcification. Pi is regulated by parathyroid hormone and 1,25-dihydroxyvitamin D. Changes in the transport of Pi are the primary factor responsible for the regulation of Pi homeostasis and the calcification process. Synthesis of calcification inhibitors is the main mechanism by which cells are able to prevent vascular calcification. Extracellular pyrophosphate (PPi) is a potent endogenous inhibitor of calcium-phosphate deposition both in vivo and in vitro. Patients with CKD show lower levels of PPi and increased activity of the enzyme alkaline phosphatase. Numerous enzymes implicated in the metabolism of PPi have been associated with vascular calcifications. PPi is synthesized from extracellular ATP by nucleotide pyrophosphatase/phosphodiesterase from extracellular ATP hydrolysis. PPi is hydrolyzed into Pi by tissue-nonspecific alkaline phosphatase. ATP can be hydrolyzed to Pi via the ectonucleoside triphosphate diphosphohydrolase family. All these enzymes must be in balance, thereby preventing calcifications. However, diseases like CKD or diabetes induce alterations in their levels. Administration of PPi could open up new treatment options for these patients.
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PMID:Role of pyrophosphate in vascular calcification in chronic kidney disease. 2913 92

Vascular calcification is a pathologic phenomenon consisting of calcium phosphate crystal deposition in the vascular walls. Vascular calcification has been found to be a risk factor for cardiovascular diseases, due to its correlation with cardiovascular events and mortality, and it has been associated with aging, diabetes, and chronic kidney disease. Studies of vascular calcification have focused on phosphate homeostasis, primarily on the important role of hyperphosphatemia. Moreover, vascular calcification has been associated with loss of plasma pyrophosphate, one of the main inhibitors of calcification, thus indicating the importance of the phosphate/pyrophosphate ratio. Extracellular pyrophosphate can be synthesized from extracellular ATP by ecto-nucleotide pyrophosphatase/ phosphodiesterase, whereas pyrophosphate is hydrolyzed to phosphate by tissuenonspecific alkaline phosphatase, contributing to the formation of hydroxyapatite crystals. Over the last decade, vascular calcification has been the subject of numerous reviews and studies, which have revealed new agents and activities that may aid in explaining the complex physiology of this condition. This review summarizes current knowledge about alkaline phosphatase and its role in the process of vascular calcification as a key regulator of the phosphate/pyrophosphate ratio.
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PMID:Tissue Non-Specific Alkaline Phosphatase and Vascular Calcification: A Potential Therapeutic Target. 3038 Oct 85