Role Of Cystatin Research Articles

The Role of Cystatin C and the Angiogenic Cytokines VEGF and bFGF in Patients with Esophageal Carcinoma

Angiogenesis is the formation of new blood vessels out of the existing vascular bed. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are potent circulating angiogenic factors, whereas cystatin C is one of the most important extracellular inhibitors of several cysteine proteinases. Because proteases degrade interstitial connective tissue and basement membranes during tumor growth and metastasis, an association between cystatin C and the angiogenic factors seems plausible. The primary aim of the present study was to investigate if such a correlation exists between these serum markers. The secondary aim was to determine the prognostic value of these circulating cytokines and cystatin C, collected prior to therapy, in patients with esophageal carcinoma.A total of 42 patients with esophageal carcinoma donated serum samples prior to therapy. VEGF and bFGF were correlated to platelet and leukocyte counts and VEGF was correlated to tumor volume (p = 0.04), whereas bFGF was not (p = 0.08). VEGF was significantly correlated with cystatin C (p = 0.027). Survival analysis showed that VEGF regarded as a continuous variable was associated with a significantly poorer survival in the univariate analysis (p = 0.023); however, this was not found for bFGF (p = 0.46). Neither of the angiogenic factors were associated with survival in the multivariate analysis. In the univariate analysis, cystatin c was correlated with survival (p = 0.01), but this was not found in the multivariate analysis (p = 0.28). In conclusion, VEGF was correlated with cystatin C, possible explanations being discussed in the present article. Results of the present study indicate that use of the angiogenic factors as prognostic factors, prior to therapy in patients with esophageal carcinoma, appears limited.

Localization of the Endogenous Cysteine Proteinase Inhibitor, Cystatin C, and the Cysteine Proteinase, Cathepsin B, to the Junctional Epithelium in Rat Gingiva

The junctional epithelium (JE) is a primary site of defense against periodontal pathogens. Cystatin C is an endogenous inhibitor of cysteine proteinases such as cathepsin B and also has antibacterial actions against periodontal pathogens. However, the distribution and role of cystatin C in JE have not been clarified. To investigate the function of cystatin C in the host defense at dentogingival junction, we examined the immunolocalization of cystatin C and cathepsin B in rat gingiva using light and electron microscopy. The JE (particularly the coronal portion) was immunopositive for cystatin C, and immunoelectron microscopy revealed that cystatin C was localized to the vesicular, granular, and vacuolar compartments of JE cells. The pattern of cathepsin B immunoreactivity in JE cells resembled that of cystatin C. Both cystatin C and cathepsin B appeared to be localized to endosomal/lysosomal compartments within JE cells. These findings suggest that cystatin C regulates cysteine proteinase activity and exerts antibacterial effects both in the lysosomal compartments of JE cells and in the intercellular spaces of the JE. Cystatin C is thus able to participate in host defense against periodontal pathogens at the dentogingival junction.

Epidermal differentiation: The role of proteases and their inhibitors

Dermatological diseases range from minor cosmetic problems to life-threatening conditions, as seen in some severe disorders of keratinization and cornification. These disorders are commonly due to abnormal epidermal differentiation processes, which result in disturbed barrier function of human skin. Elucidation of the cellular differentiation programs that regulate the formation and homeostasis of the epidermis is therefore of great importance for the understanding and therapy of these disorders. Much of the barrier function of human epidermis against the environment is provided by the cornified cell envelope (CE), which is assembled by transglutaminase (TGase)-mediated cross-linking of several structural proteins and lipids during the terminal stages of normal keratinocyte differentiation. The major constituents of the stratum corneum and the current knowledge on the formation of the stratum corneum will be briefly reviewed here. The discovery of mutations that underlie several human diseases caused by genetic defects in the protein or lipid components of the CE, and recent analyses of mouse mutants with defects in the structural components of the CE, catalyzing enzymes, and lipid processing, have highlighted their essential function in establishing the epidermal barrier. In addition, recent findings have provided evidence that a disturbed protease-antiprotease balance could cause faulty differentiation processes in the epidermis and hair follicle. The importance of regulated proteolysis in epithelia is well demonstrated by the recent identification of the SPINK5 serine proteinase inhibitor as the defective gene in Netherton syndrome, cathepsin C mutations in Papillon-Lefevre syndrome, cathepsin L deficiency infurless mice, targeted ablation of the serine protease Matriptase/MTSP1, targeted ablation of the aspartate protease cathepsin D, and the phenotype of targeted epidermal overexpression of stratum corneum chymotryptic enzyme in mice. Notably, our recent findings on the role of cystatin M/E and legumain as a functional dyad in skin and hair follicle cornification, a paradigm example of the regulatory functions exerted by epidermal proteases, will be discussed.

Role of cystatin C and cysteine proteinases in the development of mouse LS-lymphosarcoma.

The growth of LS-lymphosarcoma in CBA mice was accompanied by a decrease in the content of the major extracellular inhibitor cystatin C in the tumor, plasma and, to a lesser extent, in tissues not involved in tumor process (liver and spleen). Cyclophosphamide in a dose of 50 mg/kg prolonged the life-span of animals and decreased tumor size by 80%. Cathepsin B and L activities in the tumor tissue increased by 3 and 7 times, respectively. Cystatin C content in the tumor tissue, spleen, and plasma also increased. Cystatin C assay in tumor tissue and plasma helps to predict the rate of tumor growth and to evaluate the efficiency of antitumor therapy.

ASSESSMENT OF RENAL FUNCTION IN RENAL TRANSPLANT PATIENTS USING CYSTATIN C. A COMPARISON TO OTHER RENAL FUNCTION MARKERS AND ESTIMATES

To date, little evidence is available to define the role of cystatin C in patients with renal transplants. Thus, to assess, whether cystatin C (CysC) provides better information on renal function than other markers, CysC, creatinine clearance (CrCl), serum creatinine (SCr), β2-microglobulin (β2-M), and 125I-Iothalamate clearance were determined in 30 patients. Correlation and ROC curves were obtained and characteristics like sensitivityand specificity were calculated. Further, to evaluate the usefulness of these markers for monitoring, intraindividual coefficients of variation for CysC and SCr measurements were compared in 85 renal transplant patients. CysC correlated best with GFR, whereas SCr, CrCl and β2-M all had lower correlation coefficients. CysC was superior to SCr, even when renal function equations of were used. The diagnostic accuracy of CysC was significantly better than SCr, but did not differ significantly from CrCl and β2-M. Together, our data show that in patients with renal transplants, CysC has a similar diagnostic value as CrCl. However, it is superior to determinations of SCr. The intraindividual variation of CysC is significantly greater than that of SCr. This might be due to better ability of CysC to reffect temporary changes especially in mildly impaired GFR, most critical for early detection of rejection and other function impairment. In conclusion, CysC allows for easy and accurate assessment of renal function (GFR) in steady state renal transplant patients and is clearly superior to the commonly used serum creatinine.

Sertoli Cell and Germ Cell Cystatin C: Stage-Dependent Expression of Two Distinct Messenger Ribonucleic Acid Transcripts in Rat Testes1

Sertoli cells were shown to synthesize and secrete cystatin C, a potent inhibitor of cysteine proteases. The evidence for this observation was obtained from protein sequencing. Western analysis using antiserum specific to cystatin C, and immunoprecipitation of 35S protein secreted by cultured cells. The Western analysis with an antiserum to human cystatin C showed that cultured Sertoli cells secrete three previously reported immunoreactive forms of cystatin C: a predominant pair of proteins at 13-14 kDa and a less abundant 20-kDa protein. Immunohistochemical localization of cystatin C in sections of rat testes showed intense staining in Sertoli cells; no immunoreactivity was observed in spermatogonia or spermatocytes. A cDNA fragment for rat cystatin C was obtained by use of the polymerase chain reaction and was used as a probe in Northern analyses to examine the steady-state levels of cystatin C mRNA in intact testes and in Sertoli and spermatogenic cells. Sertoli cells contained a 700-nucleotide cystatin C transcript, and a mixed population of spermatids and spermatocytes contained a 550-nucleotide transcript. Analysis of RNA from purified spermatogenic cells revealed that round and condensing spermatids contained the 550-nucleotide transcript, while pachytene spermatocytes contained a smaller 500-nucleotide transcript. The 700-nucleotide transcript was present in testes isolated from rats of 5-79 days of age, the 500-nucleotide transcript was detected initially in testes from 24-day-old rats, and the 550-nucleotide transcript was detected initially at 35 days of age. Both the 500- and 550-nucleotide transcripts increased in abundance until 50 days of age. RNA from stage-synchronized testes showed that steady-state levels of both the 550- and 700-nucleotide transcripts were lowest in stages VI-VII of the cycle. These data suggest that the role of cystatin C in the testis may be to inhibit the proteolytic activity of the cysteine protease cathepsin L in all stages except stages VI-VII.

Cystatins--inhibitors of cysteine proteinases.

The cystatin superfamily of proteins, derived from a common ancestor, is comprised of a diverse group of potent cysteine proteinase inhibitors and antibacterial/viral agents grouped into several families. This review concentrates on family 2 cystatins, namely, the human salivary cystatins and cystatin C. Emphasis is given to their physicochemical and functional properties at both the protein and the molecular level. The role of cystatins in disease processes, including those in the oral cavity, is also discussed. Finally, future directions for cystatin research in oral biology are presented.

Cystatin activity in gingival crevicular fluid from periodontal disease patients measured by a new quantitative analysis method

Cystatins are protein inhibitors of cysteine proteinases, which are believed to play an important role in the pathogenesis of periodontal disease. In this study, we report a new sensitive method for the quantitative analysis of cystatin activity in a small amount of crude sample such as gingival crevicular fluid. Cystatin activity in the crude sample was determined by using active site-titrated papain, which is a cysteine proteinase from the plant Carica papaya. Crude samples usually contain endogenous cysteine proteinases. These competed with the added papain for the active sites of the cystatins. The cystatin-cysteine proteinase complex was able to be dissociated by the addition of papain. This competition and dissociation could interfere with the determination of cystatin activity, since some of the cysteine proteinases, such as cathepsin B, hydrolyzed the specific substrate for papain during titration with the papain. In order to exclude this interference and measure total cystatin activity, the crude sample must be alkalinized (pH 11.0) for 5 min at 4 degrees C followed by 10 min at 40 degrees C before titration with papain. The minimum detectable amount of cystatins was 20 fmol/assay when it was calculated per mole of papain inhibitory sites. Using this method, significant levels of cystatin activity were detected in all the samples of gingival crevicular fluid taken from periodontal disease patients. These results suggest that cystatins could regulate the cysteine proteinases in gingival crevicular fluid and that this new method could be useful to clarify the role of cystatins in the pathogenesis of periodontal disease.