Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nodular expansion of glomerular mesangium with increased amounts of extracellular matrix (ECM) material is pathognomic of diabetic nephropathy. The precise mechanisms involved in this accumulation are unknown. Recently, we reported using a solid-phase enzyme-linked immunosorbent assay (ELISA) technique that glomerular mesangial cells, the principal cell type residing in glomerular mesangium, accumulate 50-60% more fibronectin (FN), laminin (LM), and type IV collagen (T-IV) when cultured in medium containing high glucose (30 mM) (S. H. Ayo, R. A. Rodnik, J. Garoni, W. F. Glass II, and J. I. Kreiberg. Am. J. Pathol. 136: 1339-1348, 1990). ECM assembly is controlled by its rate of synthesis and degradation, as well as its binding and rate of incorporation into the ECM. To elucidate the mechanisms involved, pulse-chase experiments were designed to estimate ECM protein synthesis from the incorporation of Trans-35S [( 35S]methionine, [35S]cysteine) into immunoprecipitated FN, LM, and T-IV. mRNA levels were examined, and degradation rates were estimated from the disappearance of radioactivity from matrix proteins in mesangial cells previously incubated with Trans-35S. One week of growth in 30 mM glucose resulted in approximately 40-50% increase in the synthesis of all three matrix proteins compared with 10 mM glucose-grown cells. This was accompanied by a significant increase in the transcripts for all three matrix proteins (approximately twofold). The specific activity of the radiolabel in trichloroacetic acid-precipitable cell protein showed no difference between cells grown in 10 or 30 mM glucose, indicating that total protein synthesis was unchanged. After 1 wk, the rate of FN, LM, and T-IV collagen degradation was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased extracellular matrix synthesis and mRNA in mesangial cells grown in high-glucose medium. 199 70

Although high glucose (HG) has been shown to induce nuclear factor-kappaB (NF-kappaB) activation in vascular cells, the upstream regulation and the biologic significance of NF-kappaB activation in diabetic renal injury are not clear. It was, therefore, examined if HG-induced generation of reactive oxygen species (ROS) and protein kinase C (PKC) activation are involved in NF-kappaB activation in mesangial cells (MC), and the role of NF-kappaB activation in HG-induced monocyte chemoattractant protein-1 (MCP-1) expression by MC was further investigated. Recent observations suggest that MCP-1 may play a role in the development and progression of diabetic nephropathy. HG rapidly induced NF-kappaB activation in MC as estimated by electrophoretic mobility shift assay. Supershift assay suggests that most of the binding activity arose from p50/p50 and p50/p65 dimers. Antioxidants, pyrrolidine dithiocarbamate, N-acetyl-L-cystein, and trolox effectively inhibited HG-induced NF-kappaB activation in MC. HG rapidly generated dichlorofluorescin-sensitive intracellular ROS in MC as measured by laser-scanning confocal microscopy. HG also activated PKC rapidly in MC. Inhibition of PKC effectively blocked HG-induced intracellular ROS generation and NF-kappaB activation in MC. HG increased MCP-1 mRNA expression by 1.9-fold and protein secretion by 1.6-fold that of control glucose in MC transfected with control vector but not in MC transfected with dominant negative mutant inhibitor of NF-kappaB (IkappaBalphaM). Inhibition of either PKC or ROS effectively blocked HG-induced, but not basal, MCP-1 protein secretion by MC transfected with control vector. Thus this study demonstrates that HG rapidly activates NF-kappaB in MC through PKC and ROS and suggests that HG-induced NF-kappaB activation in MC may play a role in diabetic renal injury through upregulation of MCP-1 mRNA and protein expression.
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PMID:Role of high glucose-induced nuclear factor-kappaB activation in monocyte chemoattractant protein-1 expression by mesangial cells. 1191 48

The past two decades have yielded major advances in our understanding of the pathogenetic mechanisms that cause diabetic nephropathy. Of particular interest is the emerging paradigm of the recapitulation of developmental programmes within the diabetic kidney. Recently we have used the complementary techniques of suppression subtractive hybridization and Affymetrix GeneChips to assess changes in gene expression in human mesangial cells subjected to high ambient glucose concentrations and cyclic mechanical strain in vitro, the latter being models of hyperglycaemia and glomerular hypertension, respectively. In this review, we will focus on the potential role of one such differentially expressed gene, namely gremlin, in the pathogenesis of diabetic nephropathy. In the context of developmental nephrology, gremlin warrants special mention. Gremlin is a 184 amino acid protein and a member of the cysteine knot superfamily. The protein is highly conserved during evolution and is present in soluble and cell-associated forms. It belongs to a novel family of bone morphogenetic protein (BMP) antagonists that includes the head-inducing factor Cerberus and the tumour suppressor DAN. These proteins play important roles in limb development and neural crest cell differentiation. Evidence will be presented that mesangial cell gremlin expression is up-regulated by high ambient glucose, cyclic mechanical strain and transforming growth factor-beta (TGF-beta) and that gremlin may be an important modulator of mesangial cell proliferation and epithelial-mesenchymal transdifferentiation in a diabetic milieu.
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PMID:Gremlin: an example of the re-emergence of developmental programmes in diabetic nephropathy. 1238 93

SPARC (Secreted Protein, Acidic and Rich in Cysteine) is a matricellular protein that inhibits mesangial cell proliferation and also affects production of extracellular matrix (ECM) by regulating transforming growth factor-beta1 (TGF-beta1) and type I collagen in mesangial cells. This study is an investigation of the role of SPARC in streptozotocin (STZ)-induced diabetic nephropathy (DN) of 6-mo duration in wild type (WT) and SPARC-null mice. SPARC expression was evaluated by immunohistochemistry (IHC) and by in situ hybridization (ISH). Deposition of type I and IV collagen and laminin was evaluated by IHC, and TGF-beta 1 mRNA was assessed by ISH. Renal function studies revealed no significant difference in BUN between diabetic SPARC-null mice and diabetic WT mice, whereas a significant increase in albumin excretion was detected in diabetic WT relative to diabetic SPARC-null mice. Diabetic WT animals exhibited increased levels of SPARC mRNA and protein in glomerular epithelial cells and in interstitial cells, in comparison with nondiabetic WT mice. Neither SPARC mRNA nor protein was detected in SPARC-null mice. Morphometry revealed a significant increase in the percentage of the glomerular tufts occupied by ECM in diabetic WT compared with nondiabetic WT mice, although there was no difference in the mean glomerular tuft area among groups. In contrast, diabetic SPARC-null mice did not show a significant difference in the percentage of the glomerular tufts occupied by ECM relative to nondiabetic null mice. Tubulointerstitial fibrosis was ameliorated in diabetic SPARC-null mice compared with diabetic WT animals. Further characterization of diabetic SPARC-null mice revealed diminished glomerular deposition of type IV collagen and laminin, and diminished interstitial deposition of type I and type IV collagen correlated with decreases in TGF-beta 1 mRNA compared with WT diabetic mice. These observations suggest that SPARC contributes to glomerulosclerosis and tubulointerstitial damage in response to hyperglycemia through increasing TGF-beta 1 expression in this model of chronic DN.
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PMID:Amelioration of diabetic nephropathy in SPARC-null mice. 1266 Mar 31

Connective tissue growth factor (CTGF) is a cysteine-rich member of a new family of growth regulators. It is an important factor in the pathogenesis of mesangial matrix accumulation and progressive glomerulosclerosis. The present study was designed to elucidate the role of CTGF in diabetic nephropathy (DN), immunoglobulin A nephropathy (IgA-N), membranous nephropathy (MN), and minimal change nephrotic syndrome (MCNS). We evaluated the expression and localization of CTGF mRNA in surgically excised renal tissue samples from 10 patients with DN, 10 with IgA-N, 10 with MN, 10 with MCNS, and 10 normal human kidney (NHK) tissue samples, by using high-resolution in situ hybridization with digoxigenin-labelled oligonucleotide. To quantify CTGF mRNA expression, we counted all nuclei, and nuclei surrounded by CTGF-positive cytoplasm, in at least 10 randomly selected cross-sections of non-sclerotic glomeruli, and expressed the results as a percentage of total glomerular cells. In all glomeruli, CTGF mRNA was expressed mainly in glomerular intrinsic cells, including glomerular mesangial and epithelial cells and some cells of Bowman's capsule. The percentage of cells positive for CTGF mRNA was significantly higher in DN and IgA-N than in MN, MCNS and NHK. However, there was no significant difference in the percentage of CTGF mRNA-positive cells between DN and IgA-N. Our study indicates that CTGF may play an important role in the development and progression of glomerulosclerosis in DN and IgA-N, which are both accompanied by mesangial matrix expansion and comprise two major causes of end-stage renal failure.
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PMID:Glomerular expression of connective tissue growth factor mRNA in various renal diseases. 1501 39

The pathological significance of advanced glycation end product (AGE)-modified proteins deposited in several lesions is generally accounted for by their cellular interaction via the AGE receptors and subsequent acceleration of the inflammatory process. In this study, we focused on two AGE receptors-specifically, the role of SR-A in pathogenesis of diabetic nephropathy and the role of CD36 in AGE-induced downregulation of leptin by adipocytes. In terms of SR-A, diabetic wild-type mice exhibited increased urinary albumin excretion, glomerular hypertrophy, and mesangial matrix expansion, whereas SR-A-knockout mice showed reduced glomerular size and mesangial matrix area. In these diabetic SR-A-knockout mice, the number of macrophages that infiltrated into glomeruli was remarkably reduced (P < 0.05), suggesting that SR-A-dependent glomerular migration of macrophages plays an important role in the pathogenesis of diabetic nephropathy. In terms of CD36, incubation of glycolaldehyde-modified bovine serum albumin (GA-BSA) with 3T3-L1 adipocytes reduced leptin secretion by these cells. The binding of GA-BSA to these cells and subsequent endocytic degradation were effectively inhibited by a neutralizing anti-CD36 antibody. AGE-induced downregulation of leptin was protected by N-acetyl-cysteine, an antioxidant. These results indicate that the interaction of AGE ligands with 3T3-L1 adipocytes via CD36 induces oxidative stress and leads to inhibition of leptin expression by these cells, suggesting a potential link of this phenomenon to exacerbation of the insulin sensitivity in metabolic syndrome.
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PMID:Pathological roles of advanced glycation end product receptors SR-A and CD36. 1603 91

In Diabetes Mellitus (DM), glucose and the aldehydes glyoxal and methylglyoxal modify free amino groups of lysine and arginine of proteins forming advanced glycation end products (AGEs). Elevated levels of these AGEs are implicated in diabetic complications including nephropathy. Our objective was to measure carboxymethyl cysteine (CMC) and carboxyethyl cysteine (CEC), AGEs formed by modification of free cysteine sulfhydryl groups of proteins by these aldehydes, in plasma proteins of patients with diabetes, and investigate their association with the albumin creatinine ratio (ACR, urine albumin (mg)/creatinine (mmol)), an indicator of nephropathy. Blood was collected from forty-two patients with type 1 and 2 diabetes (18-36 years) and eighteen individuals without diabetes (17-35 years). A liquid chromatography-mass spectrophotometric method was developed to measure plasma protein CMC and CEC levels. Values for ACR and hemoglobin A1C (HbA1C) were obtained. Mean plasma CMC (microg/l) and CEC (microg/l) were significantly higher in DM (55.73 +/- 29.43, 521.47 +/- 239.13, respectively) compared to controls (24.25 +/- 10.26, 262.85 +/- 132.02, respectively). In patients with diabetes CMC and CEC were positively correlated with ACR, as was HbA1C. Further, CMC or CEC in combination with HbA1C were better predictors of nephropathy than any one of these variables alone. These results suggest that glucose, glyoxal, and methylglyoxal may all be involved in the etiology of diabetic nephropathy.
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PMID:Plasma protein advanced glycation end products, carboxymethyl cysteine, and carboxyethyl cysteine, are elevated and related to nephropathy in patients with diabetes. 1731 7

The therapeutic potential of lipoic acid (LA) in diabetes and diabetic nephropathy treatment was elucidated. Alloxan diabetic rabbits were treated daily for three weeks with either 10 or 50 mg of LA per kg body weight (i.p.). The following parameters were measured: 1) serum glucose, urea, creatinine and hydroxyl free radical (HFR) levels; 2) blood glutathione redox state; 3) urine albumin concentration; 4) hepatic and renal HFR levels, GSH/GSSG ratios, cysteine contents and the activities of the enzymes of glutathione metabolism; and 5) the activity of renal NADPH oxidase. Histological studies of kidneys were also performed. The treatment of diabetic rabbits with 50 mg of LA resulted in lethal hypoglycaemia in 50% of animals studied. Although the low dose of LA did not change serum glucose concentration, it decreased serum urea and creatinine concentrations, attenuated diabetes-induced decline in GSH/GSSG ratio and abolished hydroxyl free radicals accumulation in serum, liver and kidney cortex. LA did not change the activities of the enzymes of glutathione metabolism, but it elevated hepatic content of cysteine, which limits the rate of glutathione biosynthesis. Moreover, LA lowered urine albumin concentration and attenuated glomerulopathy characteristic of diabetes. However, it did not affect diabetes-stimulated activity of renal NADPH oxidase. In view of these data, it is concluded that low doses of LA might be useful for the therapy of diabetes and diabetic nephropathy. Beneficial action of LA seems to result mainly from direct scavenging of HFR and restoring glutathione redox state due to elevation of intracellular cysteine levels.
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PMID:Lipoic acid ameliorates oxidative stress and renal injury in alloxan diabetic rabbits. 1815 51

Members of the CCN (CYR61/CTGF/NOV) family have emerged as dynamically expressed, extracellular matrix-associated proteins that play critical roles in cardiovascular and skeletal development, injury repair, fibrotic diseases and cancer. The synthesis of CCN proteins is highly inducible by serum growth factors, cytokines, and environmental stresses such as hypoxia, UV exposure, and mechanical stretch. Consisting of six secreted proteins in vertebrate species, CCNs are typically comprised of four conserved cysteine-rich modular domains. They function primarily through direct binding to specific integrin receptors and heparan sulfate proteoglycans, thereby triggering signal transduction events that culminate in the regulation of cell adhesion, migration, proliferation, gene expression, differentiation, and survival. CCN proteins can also modulate the activities of several growth factors and cytokines, including TGF-beta, TNFalpha, VEGF, BMPs, and Wnt proteins, and may thereby regulate a broad array of biological processes. Recent studies have uncovered novel CCN activities unexpected for matricellular proteins, including their ability to induce apoptosis as cell adhesion substrates, to dictate the cytotoxicity of inflammatory cytokines such as TNFalpha, and to promote hematopoietic stem cell self-renewal. As potent regulators of angiogenesis and chondrogenesis, CCNs are essential for successful cardiovascular and skeletal development during embryogenesis. In the adult, the expression of CCN proteins is associated with injury repair and inflammation, and has been proposed as diagnostic or prognostic markers for diabetic nephropathy, hepatic fibrosis, systemic sclerosis, and several types of cancer. Targeting CCN signaling pathways may hold promise as a strategy of rational therapeutic design.
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PMID:Functions and mechanisms of action of CCN matricellular proteins. 1877 91

It was reported that Hcy was related to the development of kidney disease, but it remains unknown whether Hcy is an independent biomarker for diabetic nephropathy. Analytical method for simultaneous determination of aminothiols among the Hcy metabolic cycle is desirable to discover other potential biomarkers. A high-performance liquid chromatography-electrospray tandem mass spectrometric (HPLC-ESI-MS/MS) method was established for simultaneous quantitation of Cysteine (Cys), total homocysteine (tHcy), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), cystathionine (Cysta), methionine (Met), glutathione (GSH) and cysteinylglycine (Cys-gly) in plasma with N-(2-mercaptopropionyl)-glycine (MPG) as internal standard. The method had simple pretreatment without derivatization and the chromatograms show better separation of the eight aminothiols and the analytic time was 20 min. The results demonstrated that it provided an excellent linearity for all analytes over their respective concentration ranges and illustrated excellent precision and plasma recovery as well. Then, the method was applied in the case-control study of patients with diabetes mellitus (DM) and diabetic nephropathy (DN). In conclusion, it is an effective method to quantitate the concentrations of aminothiols in the human plasma. SAH and SAM were suggested as better potential biomarkers of DM and DN.
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PMID:HPLC-electrospray tandem mass spectrometry for simultaneous quantitation of eight plasma aminothiols: application to studies of diabetic nephropathy. 1908 35


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