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)

Abnormalities in extracellular matrix degradation may play a pathogenetic role in diabetic nephropathy. Cultured renal mesangial cells are known to synthesize increased amounts of matrix proteins when incubated in high glucose media (e.g., 30 mmol/l). However, the effect of glucose loading on degradative enzymes is unknown. Primary cultures of rat mesangial cells were grown until confluent in the presence of fetal calf serum (FCS) and insulin (0.67 U/ml). Cells were then cultured for 7 days in plastic wells in either 10 or 30 mmol/l glucose media containing neither FCS nor insulin. Collagenase activity in media were determined by zymography and quantitative spectrofluorometry. Cathepsin B and D activities in cell extracts were measured by spectrofluorometry (using the fluorescent substrate Z-Arg-Arg-7-amido-4-methylcoumarin) and 125I-labeled hemoglobin digestion, respectively. Gelatin-degrading activity of live mesangial cells was also determined. mRNA levels for collagenase IV, cathepsin B, and cathepsin D were determined by Northern analysis. A major band of collagenase activity with a molecular size of 72 kDa was observed in all mesangial cell media. Exposure of cells to high glucose media resulted in significant reductions in collagenase and cathepsin B activities as well as impairment in gelatin-degrading activity. Collagenase IV and cathepsin B and D mRNA levels were also decreased by glucose loading. To exclude the possibility that glucose loading was injurious to cells, 3H-leucine uptake (as a measure of protein synthesis) and membrane alkaline phosphatase activity (as a biochemical marker of viability) were not affected by the high glucose condition.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1995 Aug
PMID:Decreased degradative enzymes in mesangial cells cultured in high glucose media. 762 99

Rupture of atherosclerotic plaque resulting in intravascular thrombosis and myocardial infarction (MI), while a common sequelae of de novo atherosclerotic lesions, is an uncommon consequence of restenosis. We hypothesize that the rarity of MI associated with restenotic lesions is a result of cellular and biochemical modifications induced by the local response to mechanical injury rendering the site resistant to rupture. Clinical and angiographic features of patients presenting with symptomatic primary (n = 24) or restenotic coronary lesions (n = 12) who underwent directional atherectomy were compared. Histologic analysis and immunostaining for 92-kDa gelatinase were performed on each atherectomy specimen. There was no significant difference between the 2 groups regarding age, gender, incidence of diabetes, smoking, hypertension, hypercholesterolemia, or previous MI. Lesion length, extent, and distribution of disease and percent stenosis were not significantly different between groups. However, 8% of primary lesions were hypercellular compared with 75% of restenotic specimens (p = 0.0001). Hypercellularity in restenotic specimens was shown by adjacent section staining to be composed of smooth muscle cells. Ninety-two kDa gelatinase was expressed in 79% of primary lesions versus 0% of restenotic specimens (p = 0.0001). Thrombus was identified in 54% of primary lesions versus 22% of restenotic lesions (p <0.05). These findings suggest that, independent of clinical or angiographic influences, balloon injury induces increased lesion cellularity and reduced expression of 92-kDa gelatinase, possibly resulting in a reduced propensity for plaque rupture and thrombosis.
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PMID:Differential expression of 92-kDa gelatinase in primary atherosclerotic versus restenotic coronary lesions. 910 98

The glomerular basement membrane (GBM) is damaged in diabetes through complex mechanisms that are not fully understood. Prominent among them is nonenzymatic protein glycation leading to the formation of so-called advanced glycation end products (AGEs). We examined the effects of in vitro glycation of intact collagen type IV in bovine lens capsule (LBM) and kidney glomerular (GBM) basement membranes on their susceptibility to matrix metalloproteinases, using stromelysin 1 (MMP-3) and gelatinase B (MMP-9). Sites of cleavage of unmodified LBM collagen were located in the triple helical region. In vitro glycation by glucose severely inhibited the release of soluble collagen cleavage peptides by MMP-3 and MMP-9. The distribution of AGEs within the three domains of collagen IV (7S, triple helical, and noncollagenous NC1) were compared for LBM glycation using AGE fluorescence, pentosidine quantitation, and immunoreactivity towards anti-AGE antibodies that recognize the AGE carboxymethyllysine (CML). Marked asymmetry was observed, with the flexible triple helical domain having the most pentosidine and fluorescent AGEs but the least CML. The in vivo relevance of these findings is supported by preliminary studies of AGE distribution in renal basement membrane (RBM) collagen IV domains from human kidneys of two insulin-dependent diabetics and one normal subject. Pentosidine and fluorescent AGE distributions of diabetic RBM were similar to LBM, but the CML AGE in diabetic kidney was less in the triple helical domain than in NC1. Our results support the hypothesis that nonenzymatic glycation of collagen IV contributes to the thickening of basement membranes, a hallmark of diabetic nephropathy.
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PMID:Nonenzymatic glycation of type IV collagen and matrix metalloproteinase susceptibility. 935 Jun 53

A number of studies have shown elevated matrix metalloproteinase expression in chronic wound fluid compared to an acute wound; however, little has been done to characterize animal models in a similar manner and thus determine their usefulness. The diabetes mouse is an animal model of type II diabetes that shows impaired dermal wound healing and has been proposed as a model of human impaired wound healing. In this study we have determined the mRNA and protein expression profiles of matrix metalloproteinases 2, 3, and 9 during the first 10 d of dermal healing for the diabetes mouse and its normally healing littermate. Additionally, human wound fluid from diabetic chronic wounds and acute surgical wounds were studied to enable a comparison of the model to the human condition. We show that during the early stages of wound healing the diabetes mouse possesses significantly reduced protein levels of pro-matrix metalloproteinases 2 and 9 within the wound tissue and active matrix metalloproteinase 3 within the fluid. Pro-matrix metalloproteinase 3 levels are also significantly reduced in the diabetes mouse during the later stages of healing. These differences may be contributing to the impaired healing of the diabetes mouse; however, they differ from the human data presented here, which show elevated matrix metalloproteinase 2 and reduced matrix metalloproteinase 9 in human diabetic chronic wound fluid compared to acute wound fluid. Therefore, although clearly showing the importance of appropriate matrix metalloproteinase regulation for normal acute wound healing to occur, the diabetes mouse may not be an ideal model for study of matrix metalloproteinase involvement in human chronic wound healing.
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PMID:Differential expression of matrix metalloproteinases during impaired wound healing of the diabetes mouse. 1216 30

Genetic, endocrine, and environmental factors contribute to the development of diabetes. Much information has been gathered on the homeostasis mechanisms of glucose regulation by insulin-producing pancreatic beta cells. Here we demonstrate high expression levels of gelatinase B (matrix metalloproteinase-9, MMP-9) by neutrophils in acute pancreatitis and by ductular epithelial cells in chronic pancreatitis. Because gelatinase B processes cytokines and chemokines, we investigated whether and how gelatinase B cleaves insulin. Pure human neutrophil gelatinase B was found to destroy insulin by cleavage at 10 sites. Pancreatic islet and ductular cells are relatively spared in comparison with the complete destruction of acinar cells of the exocrine pancreas in chronic pancreatitis. High expression levels of gelatinase B are maintained in the immediate proximity of insulin-secreting beta cells. Consequently, diabetes may be worsened by enzymatic degradation of insulin by gelatinase B and by the consequent enhancement of the autoimmune process. Gelatinase B is diabetogenic in acute and chronic pancreatitis by cleaving insulin.
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PMID:Gelatinase B is diabetogenic in acute and chronic pancreatitis by cleaving insulin. 1262 33

Autoimmune diseases are characterized by inflammation and by the development and maintenance of antibodies and T lymphocytes against "self" antigens. Although the etiology of these diseases is unknown, they have a number of cellular and molecular mechanisms in common. Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor (TNF), are upregulated and activate the inflammatory process. Chemokines recruit and activate leukocytes to release proteases, including matrix metalloproteinases (MMPs). These proteases degrade proteins into remnant fragments, which often constitute immunodominant epitopes. Either by direct loading into major histocompatibility complex (MHC) molecules or after classical antigen uptake, processing and MHC presentation, these remnant epitopes are presented to autoreactive T lymphocytes. Also, posttranslationally modified remnant peptides may stimulate B cells to produce autoantibodies. This forms the basis of the "Remnant Epitopes Generate Autoimmunity" (REGA) model. We have documented evidences for this model in multiple sclerosis (MS), rheumatoid arthritis (RA) and diabetes, which are summarized here. Furthermore, three topics will be addressed to illustrate the importance of glycobiology in the pathogenesis of autoimmune diseases. In MS, gelatinase B or MMP-9 is a pathogenic glycoprotein of which the sugars contribute to its interactions with the tissue inhibitor of metalloproteinases-1 (TIMP-1) and thus assist in the determination of the enzyme activity. In RA, gelatinase B cleaves denatured type II collagen into remnant epitopes, some of which constitute immunodominant glycopeptides. This implies that immunodominant epitope scanning experiments should preferably be done with natural posttranslationally modified glycopeptides, rather than with unmodified (synthetic) peptides. Sugars can also be used as molecular probes to induce autoimmune diseases. One of the best examples is the induction of acute pancreatitis, insulitis and diabetes by streptozotocin. In addition, gelatinase B is upregulated in pancreatitis and cleaves insulin. The most efficient cleavage by gelatinase B leads to a major insulin remnant epitope.
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PMID:Remnant epitopes generate autoimmunity: from rheumatoid arthritis and multiple sclerosis to diabetes. 1471 89

Diabetes increases susceptibility to chronic skin ulceration. The etiology of chronic wound formation in diabetic individuals is multifactoral but may be accelerated by changes in the structure and function of the skin secondary to impaired fibroblast proliferation, decreased collagen synthesis, and increased matrix metalloproteinase (MMP) expression. This study explored the effects of all-trans-retinoic acid (RA) on cellular and biochemical features of diabetic human skin in organ culture. Two-mm skin biopsies from hip or ankle were obtained from diabetic subjects and incubated for 9 days in the absence or presence of 2 micro mol/L RA. Hip skin from non-diabetic individuals served as control. Following organ culture incubation, untreated and RA-treated tissue was examined histologically after staining with hematoxylin and eosin. In parallel, organ culture-conditioned medium collected on days 5 and 7 was assayed for levels of active and total MMP-1 (interstitial collagenase) and MMP-9 (gelatinase B). The same organ culture fluids were assayed for the presence of soluble collagen. In comparison with skin from non-diabetic individuals, diabetic skin demonstrated no major differences in overall epidermal thickness or collagen production (both were increased in RA-treated tissue as compared to non-RA-treated tissue). In contrast, levels of MMP-9 (active forms) were elevated in organ culture fluid from diabetic skin as compared to non-diabetic control skin. In the presence of RA, active forms of both MMP-1 and MMP-9 were reduced. Together, these data suggest that RA has the capacity to improve structure and function of diabetic skin, and that a major effect is on reduction of collagen-degrading MMPs.
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PMID:All-trans-retinoic acid suppresses matrix metalloproteinase activity and increases collagen synthesis in diabetic human skin in organ culture. 1521 72

Matrix metalloproteinases, in particular gelatinase B/MMP-9, are key mediators in autoimmune diseases like multiple sclerosis and rheumatoid arthritis, but their pathogenic roles in diabetes are not well established. Gelatinase B has previously been shown to be upregulated in pancreas tissue from patients with acute and chronic pancreatitis and was suggested to exacerbate diabetes by cleaving insulin. In this study, the role of gelatinase B in diabetes was investigated using two streptozotocin-induced animal models of type I diabetes. In both a hyperacute and a subacute model, gelatinase B upregulation was found to be associated with disease activity. However, gelatinase B deficiency did not significantly protect against diabetes development, and wild-type and gelatinase B-deficient animals behaved similarly in terms of beta-cell apoptosis or necrosis. The fact that gelatinase B was found almost exclusively as the inactive pro-enzyme in most of the streptozotocin-induced diabetic animals may explain the lack of a gelatinase B effect. On the contrary, gelatinase B was completely activated in a minority (15%) of wild-type animals. This coincided with exocrine pancreatic inflammation, as revealed by the presence of active trypsin. The discovery of in vivo activation of progelatinase B by trypsin in acute pancreatitis is extended in a model of caerulein-induced pancreatitis. In the latter model, trypsinogen activation is systematically achieved and gelatinase B is found in its active form. In conclusion, gelatinase B itself is not a causative factor but, when activated by endogenous trypsin, is a permissive factor for insulin degradation and diabetes.
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PMID:In vivo activation of gelatinase B/MMP-9 by trypsin in acute pancreatitis is a permissive factor in streptozotocin-induced diabetes. 1553 38

Cataract is a common cause of blindness and results from destruction of the microarchitecture of the lens. It is observed in many genetic syndromes, infections, inflammatory diseases and during aging. Fluctuations in lens density and light scattering by altered refraction index form the physical basis for this process, but the pathogenesis is poorly understood. Increased levels of gelatinase B/matrix metalloproteinase-9 have been reported for cataract-associated disorders such as eye inflammation and diabetes. We demonstrate that incubation of lenses with gelatinase B leads immediately to cataract. In complete eye extracts, betaB1 crystallin was identified as the major gelatinase B substrate by combination of proteomics, mass spectrometry, and Edman degradation analysis. The cleavage of betaB1 crystallin was also observed in vivo after endogenous gelatinase B-induction by the chemokine granulocyte chemotactic protein-2 in wild-type mice but not in gelatinase B-/- mice.
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PMID:Gelatinase B/matrix metalloproteinase-9 provokes cataract by cleaving lens betaB1 crystallin. 1562 92

For diabetes mellitus, little research has been done on the tissue-based or cell-based drug screening model, which has advantages over traditional animal diabetic model in high specificity, high screening volume, low cost and simple manipulation. Considering that the maintenance of complete islet tissue structure is the prerequisite for islet cells to perform their functions normally, an in vitro islet-based drug screening model for diabetes mellitus was established and evaluated. Pancreatic islets were isolated from 3 weeks old mice of either sex by collagenase digestion and density gradient centrifugation as prescribed by Ramanadham S. The volume of 0.1% (W/V) collagenase IV, 0.1% (W/V) Hyaluroridase and 0.1% (W/V) DNase I were 4 times, 2 times and 1 times that of the islets to be digested. And a 2 hours' cold digestion at 4 degrees C was followed by a 10 minutes' warm digestion at 37 degrees C. Under the optimized digestion condition, the islet recovery could be increased by 10%. The isolated islets could survive 6 weeks in vitro and show stable insulin secretion in the first 10 days after inoculation. The obtained islets were cultured in RPMI-1640 medium at 37 degrees C with 5% CO2. Then a diabetic model was established by selecting streptozotocin (STZ) as the evocator and nitric oxide (NO) as the responding index. After 1 day's inoculation, islets culture was treated with STZ, whose concentration ranged from 0 to 5.0 mmol/L. NO was measured by a colorimetric assay at 540nm based on the Griess reaction for 10 min with 0.1 mL Griess reagent and 0.1 mL culture supernatants. Insulin secretion was assayed by RIA methods. Due to the islets-related inoculation variations, NO release and insulin content were both expressed as a percentage of the value recorded in basal experiment which was in the only presence of Krebs culture medium. It was testified that the amount of NO released from islet itself remained steady at 30-35 mmol/L regardless of the changes of STZ concentration from 0 to 5.0 mmol/L. However the NO content in the supernatants of islets culture had close relationship with STZ concentration. This indicated that in this STZ-induced islet diabetic model, NO mainly comes from STZ when it dissolves in water. On the other hand, when STZ changed from 0 to 5.0 mmol/L, the dose-dependent relationship between NO content and insulin secretion showed that the increase of NO came along with the decrease of insulin secretion, which is an important symbol of islet function. As a kind of oxidative free radical, NO is capable of impair islet cells. Thus, NO is a reliable responding index of the model. The optimal STZ concentration in the model is finally determined to be 5.0 mmol/L, under which condition the NO content and insulin secretion is 10.81 times and 0.43 times that in the medium before STZ is added. So if anything is effective in lowering the NO content in the culture, it could protect islets cells from the oxidative attacks of NO. Finally, as an application of the model, the scavenging effect of KOSCr on NO was studied. In a series of KOSCr with different chromium content, all had shown better NO scavenging effects than KOS itself, which could give us an enlightenment of the influence of chromium ion on oligosaccharide. And 1 g/mL KOSCr with 3.519% chromium content can significantly inhibit the NO formation. This has lain a theoretic basis for the research of KOSCr bioactivity and quality control. These results suggested that the STZ-induced diabetic islet model which is impaired by NO free radical can be used effectively, fast and conveniently when screening potential diabetes drugs.
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PMID:[Establishment and application of the model of islet impaired by NO free radical released from streptozotocin]. 1596 20


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