Increased expression of elastolytic cysteine proteases, cathepsins S and K, in the neointima of balloon-injured rat carotid arteries.
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The matrix-degrading activity of several proteases are involved in the accelerated breakdown of extracellular matrix associated with vascular remodeling during the development of atherosclerosis and vascular injury-induced neointimal formation. Previous studies have shown that the potent elastolytic cysteine proteases, cathepsins S and K, are overexpressed in atherosclerotic lesions in human and animal models. However, the role of these cathepsins in vascular remodeling remains unclear. In the present study, the expressions of cathepsin S and K and their inhibitor cystatin C were examined during arterial remodeling using a rat carotid artery balloon-injury model. The increase in both cathepsin S and K mRNA levels was observed from day 1 and day 3 through day 14 following the induction of balloon injury, respectively. Western blotting analysis revealed that both cathepsin S and K protein levels also increased in the carotid arteries during neointima formation, coinciding with an increase elastolytic activity assayed using Elastin-Congo red, whereas, no significant change in the expressions of cystatin C mRNA and protein was observed during follow-up periods after injury. Immunohistochemistry, Western blot, and in situ hybridization showed that the increase of cathepins S and K and the decrease of cystatin C occurred preferentially in the developing neointima. These findings suggest that cathepsin S and K may participate in the pathological arterial remodeling associated with restenosis. (+info)
Serum cystatin C level is a marker of end-organ damage in patients with essential hypertension.
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High urinary albumin excretion rate (AER) has been associated with the presence of atherosclerotic vascular damages and is an independent risk factor for all causes of death and cardiovascular morbidity and mortality in essential hypertensive patients. Serum cystatin C (s-CC) is a recently identified nonglycosylated 13-kD basic protein that has been suggested to be a useful marker of glomerular filtration rate. In the present study, we investigated the relationship between s-CC level and end-organ damages in the kidney, heart, and vessels of patients with essential hypertension. Sixty patients with essential hypertension participated in the present study. Patients with renal failure were excluded. Serum-CC level was measured by a particle-enhanced turbidimetric assay. Left ventricular mass index (LVMI) and intima media thickness (IMT) in the common carotid arteries were evaluated by ultrasound images. Twenty-four-hour blood pressure was measured by a cuff-oscillometric method. Serum-CC level was negatively correlated with creatinine clearance (r=-0.617, p<0.0001). It was also correlated with mean 24-h systolic blood pressure (24h-SBP) (r=0.308, p= 0.0167), LVMI (r=0.528, p<0.0001), and IMT (r=0.539, p<0.0001). Both AER and s-CC level were independently associated with mean 24h-SBP. AER but not s-CC level was associated with HDL-cholesterol. The present study was the first to demonstrate that s-CC level is a useful and convenient parameter of renal function, and may also prove to be an early marker of the severity of end-organ damage in patients with essential hypertension. (+info)
Human evidence that the cystatin C gene is implicated in focal progression of coronary artery disease.
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OBJECTIVE: Overexpression of elastolytic cysteine and aspartic proteases, known as cathepsins, is implicated in atherogenesis. The potential significance of imbalance in expression between cathepsins and their inhibitor cystatin C in cardiovascular disease has been highlighted by the demonstration of cystatin C deficiency in human atherosclerosis and abdominal aortic aneurysms. METHODS AND RESULTS: We identified and characterized physiologically relevant polymorphisms in the promoter region of the cystatin C gene that influence cystatin C production and used these polymorphisms as a tool to examine the significance of cystatin C in coronary atherosclerosis in vivo in humans. Seven polymorphisms, all in strong-linkage disequilibrium, were identified in the cystatin C gene, of which 2 promoter polymorphisms (-82G/C and -78T/G) were functional in vitro in electromobility shift and transient transfection assays. Genotyping of 1105 individuals (237 survivors of a first myocardial infarction before age 60 and 2 independent groups comprising a total of 868 healthy individuals) revealed that the plasma cystatin C concentration was significantly lower in carriers of the mutant haplotype. Furthermore, the mutant haplotype was associated with a higher average number of stenoses per coronary artery segment in unselected postinfarction patients (N=237) undergoing routine coronary angiography. CONCLUSIONS: These results provide human evidence for an important role of cystatin C in coronary artery disease. (+info)
Eosinophilic bodies in pyloric and Brunner's gland cells.
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A previously unreported cell phenotype occurred in the pyloric and Brunner glands in two gastrectomy specimens. The cells were characterised by homogeneous, eosinophilic material in the cytoplasm. The eosinophilic material had an abnormally strong reactivity for Cystatin C, a protein found recently in the normal secretion of pyloric and Brunner's gland cells. The reason for the apparent cytoplasmic accumulation of cystatin C in the two patients described remains unclear. (+info)
Prevention of domain swapping inhibits dimerization and amyloid fibril formation of cystatin C: use of engineered disulfide bridges, antibodies, and carboxymethylpapain to stabilize the monomeric form of cystatin C.
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Amyloidogenic proteins like cystatin C and prion proteins have been shown to form dimers by exchange of subdomains of the monomeric proteins. This process, called "three-dimensional domain swapping," has also been suggested to play a part in the generation of amyloid fibrils. One variant of cystatin C, L68Q cystatin C, is highly amyloidogenic, and persons carrying the corresponding gene suffer from massive cerebral amyloidosis leading to brain hemorrhage and death in early adult life. The present work describes the production of two variants of wild type and L68Q cystatin C with disulfide bridges at positions selected to inhibit domain swapping without affecting the biological function of the four cystatin C variants as cysteine protease inhibitors. The capacity of the four variant proteins to form dimers was tested and compared with that of wild type and L68Q cystatin C. In contrast to the latter two proteins, all four protein variants stabilized by disulfide bridges were resistant toward the formation of dimers. The capacity of the two stabilized variants of wild type cystatin C to form amyloid fibrils was investigated and found to be reduced by 80% compared with that of wild type cystatin C. In an effort to investigate whether exogenous agents could also suppress the formation of dimers of wild type and L68Q cystatin C, a monoclonal antibody or carboxymethylpapain, an inactivated form of a cysteine protease, was added to systems inducing dimerization of wild type and L68Q cystatin C. It was observed that catalytic amounts of both the monoclonal antibody and carboxymethylpapain could suppress dimerization. (+info)
Cystatin C antagonizes transforming growth factor beta signaling in normal and cancer cells.
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Cystatin C (CystC) is a secreted cysteine protease inhibitor that regulates bone resorption, neutrophil chemotaxis, and tissue inflammation, as well as resistance to bacterial and viral infections. CystC is ubiquitously expressed and present in most bodily fluids where it inhibits the activities of cathepsins, a family of cysteine proteases that can promote cancer cell invasion and metastasis. Transforming growth factor beta (TGF-beta) is a multifunctional cytokine endowed with both tumor-suppressing and tumor-promoting activities. We show herein that TGF-beta treatment up-regulated CystC transcript and protein in murine 3T3-L1 fibroblasts. Moreover, CystC mRNA expression was down-regulated in approximately 50% of human malignancies, particularly cancers of the stomach, uterus, colon, and kidney. Overexpression of CystC in human HT1080 fibrosarcoma cells antagonized their invasion through synthetic basement membranes in part via a cathepsin-dependent pathway. Independent of effects on cathepsin activity, CystC also reduced HT1080 cell gene expression stimulated by TGF-beta. Invasion of 3T3-L1 cells occurred through both cathepsin- and TGF-beta-dependent pathways. Both pathways were blocked by CystC, but only the TGF-beta-dependent pathway was blocked by a CystC mutant (i.e., delta14CystC) that is impaired in its ability to inhibit cathepsin activity. Moreover, CystC and delta14CystC both inhibited 3T3-L1 cell gene expression stimulated by TGF-beta. We further show that CystC antagonized TGF-beta binding to its cell surface receptors, doing so by interacting physically with the TGF-beta type II receptor and antagonizing its binding of TGF-beta. Collectively, our findings have identified CystC as a novel TGF-beta receptor antagonist, as well as a novel CystC-mediated feedback loop that inhibits TGF-beta signaling. (+info)
Use of cystatin C determination in clinical diagnostics.
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This paper presents a current view of the possible clinical uses of cystatin C determination. Cystatin C is an inhibitor of cysteine proteases, and relatively stable in the systemic circulation it is comparatively easily determined. Although in clinical practice it is known primarily as a relatively reliable and endogenous marker for glomerular filtration, lately cystatin C analysis has been discussed in connection with the diagnostics of a variety of diseases such as early atherosclerosis, Alzheimer's dementia, vascular aneurysms, hyperhomocysteinaemia and other neurodegenerative diseases. (+info)
High prevalence of hyperhomocysteinemia related to folate deficiency and the 677C-->T mutation of the gene encoding methylenetetrahydrofolate reductase in coastal West Africa.
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BACKGROUND: Moderate hyperhomocysteinemia is a risk for neural tube defect and neurodegenerative and vascular diseases and has nutritional, metabolic, and genetic determinants. Its prevalence in sub-Saharan Africa remains unknown. OBJECTIVE: Our goal was to evaluate the prevalence of hyperhomocysteinemia and the influence of nutritional, metabolic, and genetic determinants in savanna and coastal regions of Togo and Benin. DESIGN: Volunteers were recruited from coastal (C groups; n = 208) and savanna (S group; n = 68) regions. Vitamin B-12, folate, total homocysteine (tHcy), cystatin C (a marker of glomerular filtration), and inflammatory and nutritional protein markers were measured in plasma, and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A--> C polymorphisms and the methionine synthase 2756A-->G polymorphism were examined in genomic DNA. RESULTS: Moderate hyperhomocysteinemia (tHcy > 15 micromol/L) was recorded in 62.3% and 29.4% of the subjects from the coast and savanna, respectively (P < 0.0001). A histogram distribution of tHcy in the coastal groups showed a distinct group, C2 (15% of the total group), with tHcy > 28 micro mol/L. Folate < 6.75 nmol/L (lower quartile) and MTHFRCT/TT genotype were the 2 main risk factors for moderate hyperhomocysteinemia in the whole population [odds ratios: 5.3 (95% CI: 2.5, 11.2; P < 0.0001) and 4.9 (1.6, 14.8; P = 0.0048), respectively] and in the C2 group [odds ratios: 15.9 (4.5, 56.8; P < 0.0001) and 9.0 (2.3, -35.2; P = 0.0017), respectively]. Cystatin C was another potent risk factor in the C2 group. CONCLUSION: A high prevalence of hyperhomocysteinemia in coastal West Africa, related to folate concentrations and the MTHFR 677 T allele, suggests the need to evaluate the influence of hyperhomocysteinemia on disease in this area. (+info)