Armet from whitefly saliva acts as an effector to suppress plant defences by targeting tobacco cystatin

Arginine rich, mutated in early stage of tumours (Armet), is a well-characterized bifunctional protein as an unfolded protein response component intracellularly and a neurotrophic factor extracellularly in mammals. Recently, a new role of Armet as an effector protein mediating insect-plant interactions has been reported; however, its molecular mechanisms underlying the regulation of plant defences remain unclear. We investigated the molecular mechanisms underlying whitefly-secreted Armet-mediated regulation of insect-plant interaction by agrobacterium-mediated transient expression, RNA interference, electrical penetration graph, protein-protein interaction studies, virus-induced gene silencing assay, phytohormone analysis and whitefly bioassays. Armet, secreted by Bemisia tabaci whitefly, is highly expressed in the primary salivary gland and is delivered into tobacco plants during feeding. Overexpression of the BtArmet gene in tobacco enhanced whitefly performance, while silencing the BtArmet gene in whitefly interrupted whitefly feeding and suppressed whitefly performance on tobacco plants. BtArmet was shown to interact with NtCYS6, a cystatin protein essential for tobacco anti-whitefly resistance, and counteract the negative effects of NtCYS6 on whitefly. These results indicate that BtArmet is a salivary effector and acts to promote whitefly performance on tobacco plants through binding to the tobacco cystatin NtCYS6. Our findings provide novel insight into whitefly-plant interactions.

A biophysical insight into the formation of aggregates upon trifluoroethanol induced structural and conformational changes in garlic cystatin

Intrinsic and extrinsic factors are responsible for the transition of soluble proteins into aggregated form. Trifluoroethanol is among such potent extrinsic factor which facilitates the formation of aggregated structure. It disrupts the interactive forces and destabilizes the native structure of the protein. The present study investigates the effect of trifluoroethanol (TFE) on garlic cystatin. Garlic cystatin was incubated with increasing concentration of TFE (0-90% v/v) for 4 h. Incubation of GPC with TFE induces structural changes thereby resulting in the formation of aggregates. Inactivation of garlic phytocystatin was confirmed by cysteine proteinase inhibitory activity. Garlic cystatin at 30% TFE exhibits native-like secondary structure and high ANS fluorescence, thus suggesting the presence of molten globule state. Circular dichroism and FTIR confirmed the transition of the native alpha-helical structure of garlic cystatin to the beta-sheet structure at 60% TFE. Furthermore, increased ThT fluorescence and redshift in Congo red absorbance assay confirmed the presence of aggregates. Rayleigh and turbidity assay was also performed to validate the aggregation results. Scanning electron microscopy was followed to analyze the morphological changes which confirm the presence of sheath-like structure at 60% TFE. The study sheds light on the conformational behavior of a plant protein when kept under stress condition induced by an extrinsic factor.

The Effect of Ramipril Therapy on Cytokines and Parameters of Incipient Diabetic Nephropathy in Patients with Type 1 Diabetes Mellitus

We compared the levels of transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF) and other biochemical parameters in patients with type 1 diabetes mellitus with and without incipient diabetic nephropathy (iDN) and compared them with healthy control subjects. We also measured the effect of 3 and 6 months of ramipril treatment in diabetes patients with iDN. Compared with healthy controls, TGF-β1 levels were increased in both groups of diabetes patients, whereas VEGF was only elevated in patients with iDN. Ramipril did not have a significant effect on TGF-β1 or VEGF levels. We observed a significant decrease in microalbuminuria and cystatin C following ramipril treatment. Increased VEGF levels in patients with iDN suggest a role for this cytokine in the pathogenesis of diabetic nephropathy. Cystatin C would make a suitable marker for the screening and assessment of iDN, and for the evaluation of the therapeutic efficacy of drugs.

Analysis of the K-ras/B-raf/Erk signal cascade, p53 and CMAP as markers for tumor progression in colorectal cancer patients

Colorectal cancer patients may succumb to their disease because of local recurrence or formation of metastasis. To develop a prognostic tool for these fatal types of progression, 23 patients with colorectal carcinoma were included in this study for the detection at the time of surgery of the incidence of K-ras, B-raf and p53 mutations, the phosphorylation status of Erk and the expression of cystatin-like metastasis-associated protein (CMAP) in tumor, mucosa and liver samples. Polymerase chain reaction-restriction fragment length polymorphism and PCR-SSCP were used to detect the respective mutations. The results of these assays were complemented by sequencing the K-ras, B-raf and p53 mutations. A multiplex RT-PCR assay was used to detect the CMAP mRNA levels and the phosphorylation status of Erk in tumor samples was assessed by Western blot using a phosphospecific Erk antibody. The carcinomas were classified as stages T4 (70%), T3 (17%), T2 (9%) and T1 (4%) and thus represent a group of advanced colorectal carcinomas. The carcinomas (8 out of 23, 39.1%) were mutated in K-ras codons 12 or 13 and two patients had a B-raf (V599) mutation in their tumor. Of 22 tumors, 11 (50%) were positive for pErk, indicating the activation of the RAS/RAF/ERK signaling pathway. Of the 23 tumors, 13 (65.5%) showed an increased CMAP RNA level. Notably, 10 of these 13 patients have already died and two developed liver metastasis. Mutations in p53 were found in only 6 patients (26%), with 6 being detected in carcinoma, 1 in mucosa and 1 in liver tissue. These alterations were classified as non-sense (n=1), mis-sense (n=2) and frame-shift mutations (n=1) as well as intron polymorphisms (n=5). There was a significant correlation between Erk activation and K-ras codon 12 mutation (p=0.016), but not between K-ras codon 13 or B-raf mutations and Erk activation. Furthermore, there was a significant correlation of each positive marker with tumor stage (p=0.001).

[Cystatins: cysteine proteases regulation and disturbances in tumors and inflammation]

Cystatin C belongs to the group of wide spread extracellular cysteine protease inhibitors. Using ELISA kits it was shown that the highest cystatin C concentration was in human cerebrospinal fluid and low cystatin C concentration was in human urine. In healthy young persons serum cystatin C concentration was lower than in elder patients (50-65 year old). In patients with hemoblastoses (lymphoma, lymphogranulomatosis) increased serum cystatin C concentration was normalized after effective antitumor therapy. According to these data one can conclude that serum cystatin C concentration can be used as one of the prognostic criteria in patients with several kinds of hemoblastoses.

Adult cystatin C reference intervals determined by nephelometric immunoassay

OBJECTIVE

The aim of this study was to determine the adult reference values for cystatin C (CysC) and to evaluate their consistence with those reported in the literature.

DESIGN AND METHODS

CysC was analyzed in a consecutive series of subjects (100 males and 100 females) by a nephelometric immunoassay. Medline was searched for CysC reference values.

RESULTS

CysC reference intervals showed 4-11% of variation at the upper limit. The mean upper limit was </=1.0 mg/L of CysC.

CONCLUSION

Nephelometric CysC reference intervals are consistent among different populations.

Proteomics identifies enhanced expression of stefin A in neonatal murine skin compared with adults: functional implications

BACKGROUND

Skin develops through a process of epidermal proliferation, maturation, and remodelling of the epidermis and dermis. This period also involves the maturation of the skin immune system, such that antigen applied though the skin of a neonatal mouse always results in immunosuppression, whereas in adults, immunity will occur.

OBJECTIVES

Using proteomics, to identify proteins uniquely involved in the development of the skin and skin immune system.

METHODS

Proteins were extracted from whole skin of mice aged 4 and 21 days, and separated using two-dimensional electrophoresis.

RESULTS

Of the 25 proteins that were sequenced by peptide mass fingerprinting with matrix-assisted laser desorption/ionization-time of flight-mass spectrometry, three were known markers of keratinocyte differentiation and proliferation. These were cyclophilin A, epidermal fatty acid binding protein 5 and stefin A. Of interest were the two isoforms of stefin A, an intracellular protease inhibitor, found in neonatal skin. The strong expression of stefin A in neonates was confirmed by immunohistochemical analysis, suggesting an important role in the development of the epidermis. Additionally, Western blotting identified two larger isoforms in adult skin, revealing a change in the stefin A during development.

CONCLUSIONS

We propose that stefin A is involved in development of the skin, that development of the skin and of immune function is linked, and that stefin A has an important function in neonatal skin and potentially the neonatal immune response.

Heterogeneity of cathepsin B and stefin A expression in Gleason pattern 3+3 (score 6) prostate cancer needle biopsies

BACKGROUND

There is a significant positive association of increased ratios of cathepsin B to its endogenous inhibitor stefin (cystatin) A in prostatectomy tumors with pelvic lymph node metastases. Needle biopsy diagnosis of prostate cancer is critical in initial treatment selection. The objective was to characterize cathepsin B and stefin A immunostaining patterns in needle biopsies of histologically similar Gleason pattern 3+3 (score 6) foci in relation to pretreatment clinical data.

MATERIALS AND METHODS

Immunostaining of cathepsin B and stefin A of 65 biopsy sections were imaged, quantified and analyzed with Student's t-test (p < 0.05).

RESULTS

Patients had T1c to T3b clinical stages and pre-surgery total prostate-specific antigen serum levels from 1.25 to 20.0 ng/ml. Cathepsin B and stefin A reaction products were found in the cytoplasm of basal and columnar/cuboidal cells of benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN) and neoplastic cells. Ratios of cathepsin B to stefin A were significantly higher in prostate cancer when compared to that in BPH and PIN glands.

CONCLUSION

Small foci of Gleason pattern 3+3 tumors in needle biopsies have heterogeneous cathepsin B and stefin A immunostaining. Stratification of these tumors in relation to clinical stage by cathepsin B and stefin A may assist in treatment selection.

Surface plasmon resonance imaging measurements of antibody arrays for the multiplexed detection of low molecular weight protein biomarkers

This paper describes a simple methodology for the creation of high-density multiplexed antibody arrays on gold surfaces that can be used to detect low molecular weight protein biomarkers with surface plasmon resonance imaging (SPRI). A one-step carbonyldiimidazole (CDI) surface reaction was utilized to attach antibodies onto alkanethiol-modified gold surfaces and characterized with polarization modulation FT-IR reflection absorption spectroscopy. The CDI chemistry was then employed to create an antibody microarray with array element sizes varying from 750 microm down to 200 microm. As a demonstration, a three-component antibody array was employed to detect two clinically important protein biomarkers, beta2-microglobulin (11.8 kDa) and cystatin C (13.4 kDa). SPRI measurements could simultaneously detect both of these small unlabeled proteins with no cross talk at solution concentrations from 300 nM down to 1 nM. In addition, the adsorption strengths of these biomarkers onto an antibody array were measured with SPRI and compared to those obtained from the kinetic analysis of single-channel angle shift SPR measurements.

Increased cystatin C expression in the pre-eclamptic placenta

Trophoblast invasion is regulated by proteinases and their inhibitors. Cystatin C inhibits cysteine proteinases. The serum concentration of cystatin C is increased in late pregnancy and pre-eclampsia. We aimed to investigate whether the expression of cystatin C is increased in the pre-eclamptic placenta and to investigate the expression pattern of cystatin C mRNA and protein in placental tissue. Tissue samples from the central part of the placenta from 13 normal and 22 pre-eclamptic pregnancies were included. We used real-time polymerase chain reaction (RT-PCR) and in situ hybridization for mRNA expression analysis and immunohistochemistry and Western blotting for protein expression analysis. RT-PCR showed a significantly higher expression of cystatin C mRNA in pre-eclampsia than in normal pregnancy, with the highest expression in cases with severe pre-eclampsia. In situ hybridization revealed a distinct pattern of high expression in the extravillous trophoblast cells of the basal plate and low expression in the syncytiotrophoblast covering villi. The cystatin C protein distribution matched the mRNA expression pattern. Western blot analysis revealed an increased protein expression in cases with severe pre-eclampsia and confirmed the presence of cystatin C in amniotic fluid samples. The high expression of cystatin C mRNA in the extravillous trophoblast cells of the basal plate suggests a role for cystatin C in the regulation of proteases in placentation. Placental expression and secretion of cystatin C could contribute to the elevated maternal plasma levels seen in pre-eclampsia.

Acute effects of hemodialysis on salivary flow rate and composition

AIMS

To evaluate acute effects of hemodialysis (HD) on the salivary flow rate, pH and biochemical composition before, during and after completion of a dialysis session.

MATERIAL AND METHODS

Unstimulated whole saliva (UWS) and chewing-stimulated whole saliva (CH-SWS) were collected in 94 HD patients. Salivary flow rate, pH, concentrations of total protein, albumin, cystatin C, secretory immunoglobulin A (S-IgA) and of sodium, potassium and urea were measured.

RESULTS

HD had an acute stimulating effect on the salivary flow rate (UWSbefore = 0.30+/-0.22 ml/min, UWSduring = 0.39+/-0.25 ml/min, p < 0.005). The mean pH of UWS showed a small but significant increase during HD mainly due to an increased watery secretion from the salivary glands. The salivary biochemical constituents changed markedly, but no significant difference in output was found. The electrolyte concentration did not change significantly during dialysis. The level of urea in CH-SWS declined to 40% (Ureabefore = 25.+/-6.4 mmol/l, Ureaduring = 15.3+/-4.5 mmol/1).

CONCLUSIONS

This study shows that HD has significant acute effects on both salivary secretion rate and protein concentrations in saliva. We conclude that the observed changes in salivary concentrations and proteins are mainly due to an increased watery secretion from the salivary glands.

Performance characteristics of a cystatin C immunoassay with avian antibodies

BACKGROUND

A new particle-enhanced turbidimetric immunoassay (PETIA) with avian antibodies for measuring serum/plasma cystatin C has been developed. The performance characteristics of the assay are described.

METHODS

Measurements were performed on a Roche Modular P and on an Abbott Architect ci8200 using Gentian cystatin C immunoassay.

RESULTS

Measuring range was 0.3-8.0 mg/L. Reference range was 0.57-1.09 mg/L. Total analysis time was 10 minutes. Linearity was absolute over the whole assay range. Recovery of samples and controls was within 98.6-109.4%. Total imprecision CV, measured over 20 days with two lots, was < or = 4.2%. Comparison with a particle enhanced nephelometric cystatin C immunoassay (PENIA) by linear regression resulted in a slope within 0.97-1.02 and intercept within +/-0.05 mg/L. Interference studies with drugs, anticoagulants, intralipid (< or = 11 g/L), triglycerides (< or = 14 g/L) and bilirubin (< or = 420 mg/L) showed no significant interference. Due to the use of avian antibodies, no interference with rheumatoid factor was observed. No carry-over was detected. Lower detection limit and lower quantification limit (CV < or = 6%) were both below 0.33 mg/L, which is less than the lowest standard. Sample stability was up to one month at 2-8 degrees C. Stability of the reagents at 2-8 degrees C was estimated to be 24 months. Stability of the reagents in use was minimum 9 weeks.

CONCLUSIONS

Gentian cystatin C PETIA is shown to have excellent performance between methods . Interference results are improved due to avian antibodies and a broader span of the calibration curve. Avian antibodies are also known to have better immune response than mammalian antibodies towards mammalian antigens.

Cystatin C as a marker of immune complex-associated renal impairment in a Sudanese population with visceral leishmaniasis

Renal function was studied in visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL) by means of the specific marker cystatin C and related to circulating immune complexes and cytokine production. Forty patients with VL (23 with sub-acute disease and 17 with acute disease), 17 patients with PKDL, and 22 healthy controls were included. Cystatin C, but not creatinine, was significantly raised in VL (P = 0.004). The highest levels of cystatin C were found in those with acute disease (P < 0.0001). In VL, cystatin C levels were positively correlated to circulating immune complexes and production of granulocyte-macrophage colony stimulating factor (GM-CSF), but negatively correlated to aspartate aminotransferase and lactate dehydrogenase. We conclude that cystatin C is a superior marker of glomerular function in leishmaniasis and that immune complex deposition and GM-CSF are two functions that most likely are causally involved in the mechanisms leading to glomerular dysfunction in leishmaniasis.

Cystatin B: mutation detection, alternative splicing and expression in progressive myclonus epilepsy of Unverricht-Lundborg type (EPM1) patients

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is an autosomal recessive neurodegenerative disorder caused by mutations in the cystatin B gene (CSTB) that encodes an inhibitor of several lysosomal cathepsins. An unstable expansion of a dodecamer repeat in the CSTB promoter accounts for the majority of EPM1 disease alleles worldwide. We here describe a novel PCR protocol for detection of the dodecamer repeat expansion. We describe two novel EPM1-associated mutations, c.149G > A leading to the p.G50E missense change and an intronic 18-bp deletion (c.168+1_18del), which affects splicing of CSTB. The p.G50E mutation that affects the conserved QVVAG amino acid sequence critical for cathepsin binding fails to associate with lysosomes. This further supports the previously implicated physiological importance of the CSTB-lysosome association. Expression of CSTB mRNA and protein was markedly reduced in lymphoblastoid cells of the patients irrespective of the mutation type. Patients homozygous for the dodecamer expansion mutation showed 5-10% expression compared to controls. By combining database searches with RT-PCR we identified several alternatively spliced CSTB isoforms. One of these, CSTB2, was also present in mouse and was analyzed in more detail. In real-time PCR quantification, CSTB2 expression was less than 5% of total CSTB expression in all human adult and fetal tissues analyzed. In patients homozygous for the minisatellite mutation, the level of CSTB2 was reduced similarly to that of CSTB implicating regulation from the same promoter. The physiological significance of CSTB2 remains to be determined.

INTRASCHISIS CAVITY FLUID COMPOSITION IN CONGENITAL X-LINKED RETINOSCHISIS

PURPOSE

To describe the intraschisis cavity protein composition in congenital X-linked retinoschisis (CXLRS) from two eyes of one child.

METHODS

The authors present a child with complex, Type 3 CXLRS who underwent bilateral surgical repair with autologous plasmin enzyme-assisted lens-sparing vitrectomy. Undiluted samples of intraschisis fluid and vitreous fluid from two eyes (one child) were obtained and used for protein analysis.

RESULTS

The patient underwent successful schisis repair with plasmin-assisted lens-sparing vitrectomy and silicone oil. Two unique protein bands were identified in the intraschisis cavity sample of each eye by gel electrophoresis. The proteins were identified as tenascin-C, an extracellular matrix protein involved in wound healing, and cystatin C, a ubiquitous cysteine protease inhibitor implicated in inflammation.

CONCLUSIONS

Tenascin-C has previously been described in its complex relationship with decorin and fibronectin in normal wound healing. Tenascin's upregulation in sites of inflammation and tenascin's role as an antiadhesive molecule may contribute to the pathogenesis of CXLRS. To the authors' knowledge, this is the first description of intraschisis cavity fluid.

Colocalization of cystatin M/E and cathepsin V in lamellar granules and corneodesmosomes suggests a functional role in epidermal differentiation

Cystatin M/E is a cysteine protease inhibitor with two distinct binding sites for papain-like cysteine proteases (family C1) and the asparaginyl endopeptidase (AEP) legumain of family C13. We have previously demonstrated that deficiency of cystatin M/E in mice causes ichthyosiform skin changes and barrier disruption, which could be caused by unrestrained AEP activity. Recently, we provided biochemical evidence that human cathepsin V (CTSV) and cathepsin L (CTSL) are additional biological targets for human cystatin M/E. To address the possible role of these three proteases and their inhibitor in epidermal differentiation, we investigated the localization of these proteins in normal human skin. Whereas CTSL and AEP were broadly expressed in epithelial cells of the skin, we found a specific colocalization of cystatin M/E and CTSV in the stratum granulosum and in the root sheets of the hair follicle, using immunofluorescence microscopy. Immunoelectron microscopy revealed that cystatin M/E and CTSV are separately transported within the lamellar granules. Cystatin M/E was also found in the extracellular space in the stratum corneum associated with corneodesmosomes, where it was closely associated with CTSV. Based on the striking stratum-specific colocalization of cystatin M/E and CTSV, we propose that these molecules could have an important role in epidermal differentiation and desquamation.

Estimating glomerular filtration rate in diabetes: a comparison of cystatin-C- and creatinine-based methods

AIMS/HYPOTHESIS

We compared the predictive performance of a GFR based on serum cystatin C levels with commonly used creatinine-based methods in subjects with diabetes.

SUBJECTS, MATERIALS AND METHODS

In a cross-sectional study of 251 consecutive clinic patients, the mean reference (plasma clearance of (99m)Tc-diethylene-triamine-penta-acetic acid) GFR (iGFR) was 88+/-2 ml min(-1) 1.73 m(-2). A regression equation describing the relationship between iGFR and 1/cystatin C levels was derived from a test population (n=125) to allow for the estimation of GFR by cystatin C (eGFR-cystatin C). The predictive performance of eGFR-cystatin C, the Modification of Diet in Renal Disease 4 variable formula (MDRD-4) and Cockcroft-Gault (C-G) formulas were then compared in a validation population (n=126).

RESULTS

There was no difference in renal function (ml min(-1) 1.73 m(-2)) as measured by iGFR (89.2+/-3.0), eGFR-cystatin C (86.8+/-2.5), MDRD-4 (87.0+/-2.8) or C-G (92.3+/-3.5). All three estimates of renal function had similar precision and accuracy.

CONCLUSIONS/INTERPRETATION

Estimates of GFR based solely on serum cystatin C levels had the same predictive potential when compared with the MDRD-4 and C-G formulas.

Changes in submaxillary gland gene expression in F344 rats by multiple dosing of theophylline

Multiple exposure to theophylline, a phosphodiesterase (PDE) inhibitor, induces acinar hypertrophy in the salivary gland. This study examined the effect of theophylline on the gene expression of secretory proteins and phosphodiesterases in the submaxillary gland. Male F344 rats received saline or theophylline (50 mg/kg) intraperitoneally for 4 days. The gene expressions for the secretory protein, cystatin S (CysS), and PDE subfamilies 3A and 4D in the submaxillary gland were quantified using RT-PCR. Theophylline exposure resulted in a sustained increase in mRNA expression for CysS and PDE3A, but PDE4D gene expression was unchanged. Our results suggest that submaxillary hypertrophy is primarily caused by the enhanced transcription of CysS, and that the transcription of each PDE subfamily gene is regulated differently.

Bmcystatin, a cysteine proteinase inhibitor characterized from the tick Boophilus microplus

The bovine tick Rhipicephalus (Boophilus) microplus is a blood-sucking animal, which is responsible for Babesia spp and Anaplasma marginale transmission for cattle. From a B. microplus fat body cDNA library, 465 selected clones were sequenced randomly and resulted in 60 Contigs. An open reading frame (ORF) contains 98 amino acids named Bmcystatin, due to 70% amino acid identity to a classical type 1 cystatin from Ixodes scapularis tick (GenBank Accession No. ). The Bmcystatin amino acid sequence analysis showed two cysteine residues, theoretical pI of 5.92 and M(r) of 11 kDa. Bmcystatin gene was cloned in pET 26b vector and the protein expressed using bacteria Escherichia coli BL21 SI. Recombinant Bmcystatin (rBmcystatin) purified by affinity chromatography on Ni-NTA-agarose column and ionic exchange chromatography on HiTrap Q column presented molecular mass of 11 kDa, by SDS-PAGE and the N-terminal amino acid sequenced revealed unprocessed N-terminal containing part of pelB signal sequence. Purified rBmcystatin showed to be a C1 cysteine peptidase inhibitor with K(i) value of 0.1 and 0.6 nM for human cathepsin L and VTDCE (vitellin degrading cysteine endopeptidase), respectively. The rBmcystatin expression analyzed by semi-quantitative RT-PCR confirmed the amplification of a specific DNA sequence (294 bp) in the fat body and ovary cDNA preparation. On the other hand, a protein band was detected in the fat body, ovary, and the salivary gland extracts using anti-Bmcystatin antibody by Western blot. The present results suggest a possible role of Bmcystatin in the ovary, even though the gene was cloned from the fat body, which could be another site of this protein synthesis.

Cystatin A and HIV-1 p24 antigen expression in tonsillar lymphoid follicles during HIV-1 infection and during highly active antiretroviral therapy

Cystatin A is a natural cysteine proteinase inhibitor and is found in a wide variety of normal cells. The physiologic role of Cystatin A is not fully known, however. Cystatin A is present in large amounts in follicular dendritic cells, which are important in HIV-1 pathogenesis. We analyzed Cystatin A expression in tonsillar sections from 20 patients at various stages of HIV-1 infection. There was a significant (P < 0.001) difference in Cystatin A fractions between patients and controls, with medians (ranges) of 0.61 (0.46-0.83) and 0.86 (0.78-0.90), respectively. Inverse correlations (Spearman rho) existed between Cystatin A and the rate of follicular fragmentation (rho = -0.658) and HIV-1 p24 antigen expression (rho = -0.622) in germinal centers and the amount of HIV-1 RNA in tonsillar tissue (rho = -0.765). The Cystatin A fraction declined from early chronic HIV-1 infection and was significantly lower in patients with a CD4 count below as compared with above 300 cells/muL of blood (P < 0.001), suggesting a favorable initiation of highly active antiretroviral therapy (HAART) at this level. Regeneration of Cystatin A to normal levels was shown in 11 patients 12 and 48 weeks after initiation of HAART, whereas the rate of follicular fragmentation was still elevated. Thus, we found Cystatin A to be a sensitive marker during HIV-1 infection and for regeneration of follicular lymphoid tissue during HAART.

Two-dimensional electrophoresis study of in vitro pellicle formation and dental caries susceptibility

In the present study, a proteomic approach was applied to evaluate the influence of salivary protein composition on in vitro dental pellicle formation and its possible correlation with dental caries. Whole saliva, collected from caries-free and caries-susceptible subjects, was analyzed by two-dimensional electrophoresis, and protein spots were identified by mass spectrometry. Data analysis of salivary protein composition showed a statistically significant correlation between the quantity of acidic proline-rich proteins (PRPs), lipocalin, cystatin SN and cystatin S, and samples from the caries-free group of subjects [decayed, missing or filled teeth (DMFT) = 0]. Samples from subjects with a high DMFT index appear to be correlated with high levels of amylase, immunoglobulin A, and lactoferrin. In vitro pellicle-composition experiments showed the same correlations found for whole saliva. As cystatins are known physiological inhibitors of cathepsins, the higher quantities of lipocalin, and cystatins S and SN found in the samples from the caries-free subjects suggest that inhibition of proteolytic events on other salivary proteins may indirectly provide tooth protection. The correlation between higher levels of the phosphorylated acidic PRPs 1/2 with samples from the caries-free group also suggests a protective role for these proteins.

Identification of parotid salivary biomarkers in Sjögren's syndrome by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry and two-dimensional difference gel electrophoresis

OBJECTIVES

To identify the most significant salivary biomarkers in Sjögren's syndrome (SS) using proteomic methods.

METHODS

Parotid saliva from 20 non-SS subjects and 41 primary SS patients was analysed. Protein expression profiles for each sample were generated by surface-enhanced laser desorption/ionization time-of-flight-mass spectrometry (SELDI-TOF-MS). Mean peak intensities of SS patients and non-SS subjects were compared by univariate analyses. Samples pooled by diagnosis (SS and non-SS) and labelled with different Cy dyes were compared by two-dimensional difference gel electrophoresis (2D-DIGE). Two protein levels that were most significantly different by SELDI-TOF-MS and 2D-DIGE were validated by enzyme-linked immunosorbent assay in individual samples.

RESULTS

SELDI-TOF-MS of 10-200 kDa peaks revealed eight peaks with >2-fold changes in the SS group that differed from non-SS at P < 0.005. Peaks of 11.8, 12.0, 14.3, 80.6 and 83.7 kDa were increased, while 17.3, 25.4, and 35.4 kDa peaks were decreased in SS samples. 2D-DIGE identified significant increases of beta-2-microglobulin, lactoferrin, immunoglobulin (Ig) kappa light chain, polymeric Ig receptor, lysozyme C and cystatin C in all stages of SS. Two presumed proline-rich proteins, amylase and carbonic anhydrase VI, were reduced in the patient group. Three of these ten biomarkers have not been associated previously with SS.

CONCLUSIONS

The salivary proteomic profile of SS is a mixture of increased inflammatory proteins and decreased acinar proteins when compared with non-SS. Future studies will test the ability of these biomarker levels, alone and in combination, to diagnose the salivary component of SS.

Cystatin C as a marker of renal function immediately after liver transplantation

To verify whether cystatin C may be of some use as a renal function marker immediately after orthotopic liver transplantation (OLT), we compared serum cystatin C (S(Cyst)), serum creatinine (S(cr)), and creatinine clearance (C(cr)) levels with the glomerular filtration rate (GFR). On postoperative days 1, 3, 5, and 7, S(Cyst) and S(cr) was measured in simultaneously drawn blood samples, whereas C(cr) was calculated using a complete 24-hour urine collection. The GFR was determined on the same days by means of iohexol plasma clearance (I-GFR). The correlation between 1/S(Cyst) and I-GFR was stronger than that of 1/S(cr) or C(cr) (P< 0.01). In the case of moderate reductions in I-GFR (80-60 mL/minute/1.73 m), S(cr) remained within the normal range, whereas the increase in S(cyst) was beyond its upper limit; for I-GFR reductions to lower levels (59-40 mL/minute/1.73 m), S(cr) increased slightly, whereas S(cyst) was twice its upper normal limit. When we isolated all of the I-GFR values on days 3, 5, and 7 that were > or = 30% lower than that recorded on the first postoperative day, S(Cyst)(P< 0.0001) and S(cr) (P< 0.01) levels were increased, whereas C(cr) remained unchanged (P = 0.09). Receiver operating characteristic (ROC) area-under-the-curve analysis showed that the diagnostic accuracy of S(cyst) was better than that of S(cr) and C(cr). S(cyst) levels of 1.4, 1.7, and 2.2 mg/L respectively predicted I-GFR levels of 80, 60, and 40 mL/minute/1.73 m. In conclusion, cystatin C is a reliable marker of renal function during the immediate post-OLT period, especially when the goal is to identify moderate changes in GFR.

Overexpression of stefin A in human esophageal squamous cell carcinoma cells inhibits tumor cell growth, angiogenesis, invasion, and metastasis

PURPOSE

Evidence is accumulating that an inverse correlation exists between stefin A level and malignant progression. The aim of this study is to investigate the role of stefin A in human esophageal squamous cell carcinoma cells and to evaluate the possibility of stefin A for cancer therapy.

EXPERIMENTAL DESIGN

We stably transfected stefin A cDNA into human EC9706 or KYSE150 esophageal squamous cell carcinoma cells. Subsequently, we evaluated the effect of stefin A overexpression on cell growth, cathepsin B activity, cell motility and invasion, tumor growth, and metastasis. Immunoanalysis was done to assess the expression of factor VIII and to support the localization of stefin A and cathepsin B. We also evaluated the effect of CA074Me, a selective membrane-permeant cathepsin B inhibitor.

RESULTS

Both transfection of stefin A and treatment with 10 micromol/L CA074Me significantly reduced cathepsin B activity and inhibited the Matrigel invasion. Combination of both further reduced cathepsin B activity and inhibited the Matrigel invasion. Overexpression of stefin A delayed the in vitro and in vivo growth of cells and significantly inhibited lung metastasis compared with 50% of lung metastasis in xenograft mice from EC9706 or empty vector cells. Transfection with stefin A showed a dramatic reduction of factor VIII staining in the tumors of xenograft mice.

CONCLUSIONS

Our data strongly indicate that stefin A plays an important role in the growth, angiogenesis, invasion, and metastasis of human esophageal squamous cell carcinoma cells and suggest that stefin A may be useful in cancer therapy.

Cystatin-C and inflammatory markers in the ambulatory elderly

PURPOSE

Inflammatory factors are elevated in persons with severe renal dysfunction, but their association across all levels of renal function is unclear. We compared cystatin-C, a novel marker of renal function, with creatinine and estimated glomerular filtration rate (eGFR) as predictors of C-reactive protein and fibrinogen levels.

METHODS

This study is a cross-sectional analysis to evaluate cystatin-C, creatinine, and eGFR as predictors of the inflammatory markers C-reactive protein and fibrinogen. Participants included 4637 ambulatory elderly patients from the Cardiovascular Health Study. Multivariate linear regression was used to determine the independent associations of each renal function measurement with the inflammatory marker outcomes.

RESULTS

After adjustment for confounding factors, cystatin-C was correlated with both C-reactive protein (coefficient = 0.13; 95% confidence interval: 0.10-1.16, P <.0001) and fibrinogen levels (0.15; 0.13-0.18, P <.0001). Associations were larger than those for creatinine and C-reactive protein (0.05; 0.02-0.07, P = .003) or fibrinogen (0.07; 0.04-0.10, P <.0001). Adjusted levels of C-reactive protein increased incrementally across quintiles of cystatin-C, from a median of 2.2 mg/L in quintile 1 to 3.7 mg/L in quintile 5. In contrast, both C-reactive protein and fibrinogen had U-shaped associations with quintiles of creatinine and eGFR, because the inflammatory markers were equivalently elevated in quintiles 1 and 5.

CONCLUSIONS

The finding of a significant linear association of cystatin-C and inflammation markers suggests that even small reductions in renal function may be associated with adverse pathophysiologic consequences.

Kidney function as a predictor of noncardiovascular mortality

Chronic kidney disease is associated with a higher risk for cardiovascular mortality, as well as all-cause mortality. Whether chronic kidney disease is a predictor of noncardiovascular mortality is less clear. To further explore the latter, the association of kidney function with total noncardiovascular mortality and cause-specific mortality was assessed in the Cardiovascular Health Study, a community-based cohort of older individuals. Kidney disease was assessed using cystatin C and estimated GFR in 4637 participants in 1992 to 1993. Participants were followed until June 30, 2001. Deaths were adjudicated as cardiovascular or noncardiovascular disease by committee, and an underlying cause of death was assigned. The associations of kidney function with total noncardiovascular mortality and cause-specific mortality were analyzed by proportional hazards regression. Noncardiovascular mortality rates increased with higher cystatin C quartiles (16.8, 17.1, 21.6, and 50.0 per 1000 person-years). The association of cystatin C with noncardiovascular mortality persisted after adjustment for demographic factors; the presence of diabetes, C-reactive protein, hemoglobin, and prevalent cardiovascular disease; and measures of atherosclerosis (hazard ratio 1.69; 95% confidence interval 1.33 to 2.15, for the fourth quartile versus the first quartile). Results for estimated GFR were similar. The risk for noncardiac deaths attributed to pulmonary disease, infection, cancer, and other causes was similarly associated with cystatin C levels. Kidney function predicts noncardiovascular mortality from multiple causes in the elderly. Further research is needed to understand the mechanisms and evaluate interventions to reduce the high mortality rate in chronic kidney disease.

Cystatin C and subclinical brain infarction

Subclinical brain infarcts (SBI) are common in the elderly and are associated with covert neurologic and cognitive impairment. Although renal impairment is associated with accelerated cerebrovascular disease and an increased risk for clinically apparent brain infarct, few studies have examined the relationship between renal function and SBI, and these may have been limited by the inaccuracy of creatinine as a renal function marker. A cross-sectional study was performed among older adults in the Cardiovascular Health Study to examine associations between SBI and two serum markers of renal function: Serum creatinine (SCr) and cystatin C (CysC). Patients had cranial magnetic resonance imaging and renal markers measured in 1992 to 1993. Logistic regression was used to estimate the associations between renal function (estimated by 1/SCr and 1/CysC) and SBI, controlling for potential confounding factors. SBI were present in 789 (28.7%) of 2784 participants. A linear association with SBI was observed for 1/CysC (per 1-SD decrement; odds ratio [OR] 1.20; 95% confidence interval [CI] 1.09 to 1.32; P < 0.001) but not for 1/SCr (OR 1.08; 95% CI 0.98 to 1.19; P = 0.14), for which a quadratic U-shaped association was suggested (P = 0.004). In a model with both markers, 1/CysC was linearly associated with SBI (OR 1.26; P < 0.001), whereas 1/SCr was not (OR 1.06; P = 0.3). The prevalence of SBI was directly associated with quintile of CysC, whereas the association between SCr and SBI was U-shaped, with greater prevalence at high and low levels. Compared with creatinine, CysC, a novel marker of renal function, has a stronger and more direct association with SBI in the elderly.

Labelling of four distinct trophozoite falcipains of Plasmodium falciparum by a cystatin-derived probe

Trophozoite cysteine protease (TCP) activity, isolated from Plasmodium falciparum soluble 100,000 g extracts, displayed native falcipain-1 kinetic parameters towards peptidyl substrates. The labelling of either isolated TCP or soluble 100,000 g extracts by a cystatin-derived probe (biotinyl-Leu-Val-Gly-CHN2) revealed a single band of ca. 30 kDa by SDS-PAGE, which was resolved into four spots displaying isoelectric points (pI) from 4.7 to 5.3 after two-dimensional separation. The molecular mass and pI correspond to those of falcipain-3, falcipain-2, falcipain-2' and falcipain-1, respectively. The two central spots were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry as falcipain-2 and falcipain-2'. This activity-based probe represents a potential tool for profiling active falcipains in parasites.

Cystatin A inhibits IL-8 production by keratinocytes stimulated with Der p 1 and Der f 1: Biochemical skin barrier against mite cysteine proteases

BACKGROUND

Der p 1 and Der f 1 are the most immunodominant allergens produced by house dust mites and are suspected to be involved in the pathogenesis of allergy through their cysteine protease activity. However, stimulation of keratinocytes by these protease allergens and protective systems in the skin against them have not been well investigated.

OBJECTIVE

We purified and identified the dominant skin-derived inhibitor against the proteolytic activities of these allergens and analyzed its effect on keratinocyte activation.

METHODS

Recombinant allergens were used for the experiments. We analyzed whether human sweat inhibits the enzymatic activities of Der p 1 and Der f 1 and used sweat as the skin-derived material to isolate the inhibitor. The inhibitor was purified by means of column chromatography and subsequently identified by means of protein sequencing and immunoblotting. Keratinocytes were stimulated with the allergens in the absence or presence of the inhibitor, and the concentration of secreted IL-8 was measured.

RESULTS

Sweat inhibited the proteolytic activities of Der p 1 and Der f 1. The sweat inhibitor was identified as cystatin A. The stimulation of normal human keratinocytes and the human keratinocyte cell line HaCaT with these protease allergens upregulated IL-8 secretion, and addition of cystatin A blocked this upregulation. Normal human keratinocytes secreted cystatin A into the medium.

CONCLUSIONS

The proteolytic activity of Der p 1 and Der f 1 stimulates human keratinocytes in vitro. Cystatin A produced by keratinocytes is the dominant biochemical skin barrier that eliminates the enzymatic activity of these mite cysteine proteases and prevents them from stimulating keratinocytes.

Comparative proteomic analysis of human whole saliva

Human saliva performs a wide variety of biological functions that are critical for the maintenance of the oral health. Various functions include lubrication, buffering, antimicrobial protection, and the maintenance of mucosal integrity. In addition, whole saliva may be analysed for the diagnosis of human systemic diseases, since it can be readily collected and contains identifiable serum constituents. By using proteomic approach, we have established a reference proteome map of human whole saliva allowing for the resolution of greater than 200 protein spots in a single two-dimensional polyacrylamide gel. Fifty-four protein spots, comprised of 26 different proteins, were identifies using N-terminal sequencing, mass spectrometry, and/or computer matching with protein database. Ten proteins, whose levels were significantly different when bleeding had occurred in the oral cavity, were discussed in this study. These 10 proteins include alpha-1-antrypsin, apolipoprotein A-I, cystatin A, SA, SA-III, and SN, enolase I, hemoglobin beta-chain, thioredoxin peroxiredoxin B, as well as a prolactin-inducible protein. The proteomic approach identifies candidates from human whole saliva that may prove to be of diagnostic and therapeutic significance.

Inhibitory properties of cystatin F and its localization in U937 promonocyte cells

Cystatin F is a recently discovered type II cystatin expressed almost exclusively in immune cells. It is present intracellularly in lysosome-like vesicles, which suggests a potential role in regulating papain-like cathepsins involved in antigen presentation. Therefore, interactions of cystatin F with several of its potential targets, cathepsins F, K, V, S, H, X and C, were studied in vitro. Cystatin F tightly inhibited cathepsins F, K and V with Ki values ranging from 0.17 nM to 0.35 nM, whereas cathepsins S and H were inhibited with 100-fold lower affinities (Ki approximately 30 nM). The exopeptidases, cathepsins C and X were not inhibited by cystatin F. In order to investigate the biological significance of the inhibition data, the intracellular localization of cystatin F and its potential targets, cathepsins B, H, L, S, C and K, were studied by confocal microscopy in U937 promonocyte cells. Although vesicular staining was observed for all the enzymes, only cathepsins H and X were found to be colocalized with the inhibitor. This suggests that cystatin F in U937 cells may function as a regulatory inhibitor of proteolytic activity of cathepsin H or, more likely, as a protection against cathepsins misdirected to specific cystatin F containing endosomal/lysosomal vesicles. The finding that cystatin F was not colocalized with cystatin C suggests distinct functions for these two cysteine protease inhibitors in U937 cells.

[Detection of impaired renal function: is the modern serologic marker cystatin C more accurate than the 99mTc-MAG3 clearance?]

AIM

Renal function is usually determined by means of creatinine-clearance, and of serum Cystatin C, the latter with increasing frequency. The present study analyses, whether the diagnostic accuracy of (99m)Tc-MAG(3) clearance is comparable to that of these modern serologic methods.

PATIENTS, METHODS

71 consecutive adult Caucasian patients (42 female, 29 male; age 50 +/- 16 yrs., range 20-83) who were referred to a nuclear medicine department for determination of bilateral renal function with (99m)Tc-MAG(3) were included. Following sufficient hydration, 10 ml of blood were taken for determination of Cystatin C and creatinine in serum prior to i.v. injection of the radiotracer. According to the recommendations of the National Kidney Foundation, glomerular filtration rate (GFR) was calculated from serum creatinine using either Cockcroft & Gault and Modification of Diet in Renal Disease (MDRD) study equation. These estimates of GFR served as reference. Cystatin C is a low molecular protein produced by all nuclear cells and is eliminated to 85 % by glomerular filtration. Analysis of (99m)Tc-MAG(3) clearance was performed by means of Bubeck's formula.

RESULTS

Linear regression analysis produced Pearson's correlation coefficients of r = 0.68 and r = -0.69 for the comparison of either Cystatin C and (99m)Tc-MAG(3) clearance with the Cockcroft & Gault equation. The comparison of Cystatin C and (99m)Tc-MAG(3) clearance with MDRD study equation resulted in correlation coefficients of r = 0.755 and r = -0.77. None of these differences were significant. The exclusion of renal impairment or the detection of an at least moderate renal impairment revealed again no significant differences between Cystatin C and (99m)Tc-MAG(3) clearance.

CONCLUSIONS

Cystatin C and (99m)Tc-MAG(3) clearance are equally suited to exclude renal impairment or to detect a relevant renal impairment. Differences between both procedures are more likely a result of the applied reference method.

Apport de l’analyse protéomique associant électrophorèse bi-dimensionnelle et spectrométrie de masse en lacrymologie

PURPOSE

Identification of a lacrimal protein by proteomic analysis, i.e., two-dimensional electrophoresis and mass spectrometry.

MATERIAL AND METHODS

We studied the tears of a 25-year-old female with adrenal gland hyperplasia and hyperandrogenism complaining of chronic dryness and mild bilateral papillary hypertrophy. An allergologic workup was negative. Agarose electrophoresis of the tears showed a bilateral high level of rapid migrated proteins.

RESULTS

Dodecyl sulfate polyacrylamide gel electrophoresis of the tears from both eyes showed a highly stained 15-kDa band after Coomassie colloidal blue coloration compared to controls. On two-dimensional electrophoresis, this band focused on a single spot at pI 7.0. After tryptic digestion in gel, peptide mass fingerprint analysis by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry provided clear identification of cystatin SN. It is known that mRNA regulated by androgens and encoding glycoproteins homologous to human cystatin exists in the rat lacrimal gland.

CONCLUSION

We conclude that the hyperandrogenism of the patient may be cause for the hypersecretion of this cystatin SN, giving an explanation for the high level of rapid migrated proteins (lipocalins). This result provides a concrete example of the proteomic tool used to identify lacrimal proteins, still largely unknown.

Differentially expressed protein markers in human submandibular and sublingual secretions

Proteome analysis of secretions from individual salivary glands is important for understanding the health of the oral cavity and pathogenesis of certain diseases. However, cross-contamination of submandibular (SM) and sublingual (SL) glandular secretions can occur. The close anatomic relationship of the SM and SL ductal orifices can lead to such contamination. Additionally, these glands may share common ducts. To insure the purity of SM/SL secretions for proteomic analysis, it is important to develop unique biomarkers which could be used to verify the integrity of the individual glandular saliva. In this study, a proteomics approach based on mass spectrometry and gel electrophoresis techniques was utilized to identify and verify a set of proteins (cystatin C, calgranulin B and MUC5B mucin), which are differentially expressed in SM/SL secretions. SM/SL fluids were obtained from nine healthy subjects. Cystatin C was found to be an SM-selective protein as it was found in all SM fluids but not detected in two SL fluids. MUC5B mucin and calgranulin B, on the other hand, were found to be SL-selective proteins. All SL samples contained MUC5B mucin, whereas MUC5B mucin was not detected in four SM samples. Eight of the SL samples contained calgranulin B; however, calgranulin B was absent in eight SM samples. This set of protein markers, especially calgranulin B, can be used to determine the purity of SM/SL samples, and therefore identify potential individuals who do not exhibit cross-contaminated SM/SL secretions, an important requirement for subsequent proteome analysis of pure SM and SL secretions.

Up regulation of cathepsin K expression in articular chondrocytes in a transgenic mouse model for osteoarthritis

OBJECTIVES

To study the expression of cysteine proteinases, particularly cathepsin K, and their extracellular inhibitor cystatin C in articular cartilage of transgenic Del1 mice which harbour a short deletion mutation in a type II collagen transgene and are predisposed to early onset osteoarthritis.

METHODS

Northern analysis was used to measure mRNA levels of cathepsins B, H, K, L, and S, and cystatin C in total RNA extracted from knee joints of Del1 mice, using their non-transgenic litter mates as controls. Immunohistochemistry and morphometry was used to study the distribution of cathepsin K and cystatin C in the knee joints.

RESULTS

Up regulation of cathepsin K mRNA expression was seen in the knee joints of transgenic Del1 mice at the onset of cartilage degeneration. Cathepsin K was found near sites of matrix destruction in articular chondrocytes, particularly in clusters of proliferating cells, and in calcified cartilaginous matrix. In intact articular cartilage of control animals, cathepsin K was only seen in a small number of chondrocytes. Upon aging, control animals also developed osteoarthritis, which was accompanied by increased cathepsin K expression. Cystatin C was mostly localised in and around chondrocytes located in calcified cartilage, with no obvious association with the onset of cartilage degeneration.

CONCLUSION

The temporospatial distribution of cathepsin K in osteoarthritic cartilage suggests a role for this enzyme in the pathogenesis of osteoarthritis. Because cathepsin K can digest cartilage matrix components it may contribute to the development of osteoarthritic lesions. These data may provide new clues for the development of treatments aimed at preventing cartilage degeneration.

Cysteine proteinase inhibitor cystatin C in squamous cell carcinoma of the head and neck: relation to prognosis

To determine the role of the cysteine proteinase inhibitor cystatin C in the invasive behavior of squamous cell carcinoma of the head and neck (SCCHN), Cystatin C protein level was measured in 82 pairs of primary tumour tissue and adjacent noncancerous mucosa, using the enzyme-linked immunosorbent assay. The median level of cystatin C in tumour tissue was 1.18 times lower than that in corresponding mucosa (P=0.031). In normal mucosa samples, the cystatin C level was influenced by the site of sampling: it was lower in nonlaryngeal tissue samples (oral cavity, oro- or hypopharynx) than in laryngeal samples (P=0.004). The tumour cystatin C level correlated inversely with pN-stage (P=0.047), whereas a trend of lower cystatin C levels was observed in the group with extranodal tumour extension compared to those with no extranodal spread (P=0.069). In univariate analysis, the patients with low tumour cystatin C levels exhibited poor disease-free survival (DFS, P=0.013) and disease-specific survival (DSS, P=0.013). In multivariate analysis, the most powerful predictor of survival was pN-stage (DFS: P=0.040, HR 2.78; DSS: P=0.011, HR 4.36,), followed by the cystatin C level (DFS: P=0.043, HR 0.22; DSS: P=0.067, HR 0.25). When comparing the prognostic strength of cystatin C to that of stefin A, another cysteine proteinase inhibitor, which emerged as the most significant prognosticator for survival in our previous study analysing the same cohort of patients, stefin A proved to be significantly more reliable predictor for both DFS and DSS than cystatin C. Our results indicate that cystatin C is implicated in the invasive behavior of SCCHN, and that there are variations in regulation of proteolytic pathways under nonmalignant conditions, inherent to individual subsites inside the upper aerodigestive tract. The correlation between high cystatin C levels and improved survival concurs with the concept of the protective role of high levels of cysteine proteinase inhibitors in tissue homogenates that has been previously suggested by the survival results in breast and lung carcinoma as well as SCCHN.

Chronic Renal Insufficiency and Cardiovascular Events in the Elderly: Findings From the Cardiovascular Health Study

In the Cardiovascular Health Study, the authors sought to evaluate the impact of chronic renal insufficiency (CRI) on cardiovascular risk status and outcomes in a representative sample of community-dwelling elderly adults. Defined as a serum creatinine level > or =1.3 mg/dL in women and > or =1.5 mg/dL in men, CRI was present in 647 (11%) of 5808 participants. At baseline, the prevalence of clinical or subclinical cardiovascular disease was 64% in participants with CRI and 43% in those without CRI (odds ratio, 2.34; 95% confidence interval, 1.96-2.80). The incidence of cardiovascular disease events during follow-up was 3% per year in participants with creatinine levels <1.10 mg/dL and increased steadily to reach 7% per year in those with creatinine > or =1.70 mg/dL. Among the possible mediators for the association between CRI and cardiovascular morbidity are inflammatory (C-reactive protein, fibrinogen, and interleukin-6) and hemostatic (factor VII, factor VIII, plasmin-antiplasmin product, and D-dimer) biomarkers, all of which were significantly elevated in Cardiovascular Health Study participants with CRI. Future studies should evaluate the contribution of novel and traditional cardiovascular risk factors to the cardiovascular risk of elderly persons with CRI. The identification of CRI in the elderly and the use of cardiovascular prevention therapies represent a major opportunity to reduce their burden of cardiovascular morbidity.

Thermal and guanidine hydrochloride-induced denaturation of human cystatin C

Wild-type human cystatin C is directly involved in pathological fibrils formation, leading to hemorrhage, dementia and eventually death of people suffering from cerebral amyloid angiopathy. Some studies on cystatin C oligomerization have been already done but some points are still unclear. In order to learn more about this important process, we have investigated thermal and chemical (guanidine hydrochloride-induced) denaturation of human cystatin C. Studies performed using tryptophan fluorescence, calorimetry, circular dichroism and Fourier transform infrared spectroscopy demonstrate that neither chemical nor thermal denaturation of hCC are simple two-state events. One recognized intermediate form was dimeric cystatin C, whose appearance was preceded mainly by changes in the L2 binding loop. The other form occurred only in the chemical denaturation process and was characterized by partially recovered interactions maintaining the protein tertiary structure. Our studies also strongly indicate that the beta-structural motif of cystatin C is directly implicated in formation of temperature-induced aggregates.

Soybean: feed quality and safety. Part 1: biologically active components. A review

A large number of soybean components have diverse biological activities. These include hormonal, immunological, bacteriological and digestive effects. The presently known allergens are listed. The divergence between chemical evaluation and biological value is highlighted. The following components are discussed: Kunitz inhibitor, Bowman-Birk inhibitor, saponins, soyacystatin, phytoestrogens (daidzein, glycitein, genistein), Maillard products, soybean hydrophobic protein, soy allergens, lecithin allergens, raffinose, stachyose, 2-pentyl pyridine. The studies describing the effects of the isolated components are reviewed.

Use of cystatin C determination in clinical diagnostics

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.

Salivary cystatin activity and cystatin C in experimental gingivitis in non-smokers

BACKGROUND

Subjects with natural gingivitis and periodontitis have elevated levels of salivary cystatins compared to periodontally healthy individuals. Experimental gingivitis studies, however, have yielded conflicting results.

AIM

The present study investigated whether experimentally induced gingivitis is associated with changes in salivary cystatin levels.

MATERIAL & METHODS

Plaque scores, bleeding indexes and whole saliva samples of 35 non-smoking young adults were collected at the start and at the end of an experimental gingivitis trial, and 3 weeks after resuming oral hygiene. The saliva samples were assayed for protein concentrations, cystatin activity and cystatin C concentration.

RESULTS

During experimental gingivitis, plaque and bleeding scores increased significantly in all subjects and subsequently decreased significantly after reinstalment of oral hygiene procedures. No significant changes were observed for the protein concentration, cystatin activity and cystatin C concentration. No significant relation could be established between these salivary parameters and bleeding on marginal probing.

CONCLUSION

The present study confirms earlier results from Lie et al. (2001) that no significant changes occur in salivary cystatin activity and cystatin C concentration during and after experimental gingivitis.

Decreased levels of cystatin C, an inhibitor of the elastolytic enzyme cysteine protease, in acute and subacute phases of kawasaki disease

Elevation of tissue-destructive proteases has been reported in acute Kawasaki disease. Cystatin C is a naturally occurring inhibitor of elastolytic cysteine protease in humans. Serum cystatin C deficiency in human beings has been linked to atherosclerosis and aortic aneurysms. We investigated the serum levels of cystatin C during acute Kawasaki disease. Serum samples from 17 acute Kawasaki disease patients were collected before and after immunoglobulin therapy and also at a median of 17 days after the therapy. Eight adults and 10 children without intercurrent infections served as control patients. Children with Kawasaki disease prior to therapy had significantly lower levels of cystatin C compared to adults (p = 0.002) and control children (p = 0.001). The low levels persisted 1-106 days after the therapy. Compared to control children and adults, children with Kawasaki disease had significantly lower serum levels of cystatin C in the acute stage before immunoglobulin therapy and in the subacute phase after the immunoglobulin therapy.

Evaluation of cystatin C and beta-2 microglobulin as markers of renal function in patients with type 2 diabetes mellitus

BACKGROUND

Despite recent studies showing that serum cystatin C (CC) is a better marker for GFR than the ubiquitously used serum creatinine, its clinical utility remains under evaluation.

METHODS

To evaluate their usefulness in patients with type 2 diabetes mellitus (DM), serum concentrations of CC, beta-2 microglobulin (B2M) and creatinine were measured in 105 (38 males, 67 females) Kuwaiti patients with type 2 DM. The results were compared with creatinine clearance (Ccr), which was measured (mCcr) and estimated (eCcr) with the Cockroft-Gault formula, and correlated with 24-h urine protein and early morning urine albumin/creatinine excretion ratio.

RESULTS

In patients with eCcr and mCcr results (n=51), eCcr and mCcr showed significant correlation with each other (r's=.86, P<.0001) with no significant difference between the two. In all patients (n=105), CC and B2M showed significant correlation with each other (r's=.82, P<.0001) and with serum creatinine concentration (r's=.77 and.84, respectively, P<.0001). Serum CC, B2M and creatinine showed significant (P<.001) inverse correlation with eCcr (r's=-.63, -.61 and -.76, respectively). Partial correlations after correcting for age and sex improved the correlation of serum creatinine with eCcr (r=-.81, P<.0001), but there was no significant change in the correlations of CC and B2M with eCcr (r=-.65, P<.0001 and r=-.62, P<.0001, respectively). Receiver operating characteristic (ROC) plots for serum CC, B2M and creatinine for detection of changes in the eCcr showed that the area under the ROC curve+/-S.E. is 0.897+/-0.119 for CC, 0.871+/-0.091 for B2M and 0.785+/-0.087 for serum creatinine. There was no statistically significant difference between the areas under the curve (AUC) for serum creatinine and CC (P=.07) and B2M (P=.12). CC had the highest sensitivity for detection of eCcr (<60 ml/min/1.73 m(2)) at routinely used cutoff values. CC was also the best discriminator when patients with normoalbuminuria were compared with patients with microalbuminuria.

CONCLUSION

Although there is no significant difference in the overall diagnostic accuracies of CC, B2M and creatinine for the detection of changes in the GFR, CC is the most sensitive marker at routinely used cutoff values and would be more clinically useful than B2M or serum creatinine in diabetic patients.

Identification of the human salivary cystatin complex by the coupling of high-performance liquid chromatography and ion-trap mass spectrometry

Human salivary cystatins, five major (S, S1, S2, SA, SN) and two minor (C and D), are multifunctional proteins playing a different role in the oral environment. Salivary cystatin SN is able to effectively inhibit lysosomal cathepsins B, C, H and L and cystatin SA inhibits cathepsins C and L in vitro. These activities suggest, particularly for cystatin SN, an important role in the control of proteolytic events in vivo. Differently, cystatins S are involved, together with statherin, in the mineral balance of the tooth. Due to their distinct role, a reliable method for identification and quantification of the different cystatins, as well as of possible truncated and derived forms, could be helpful for the assessment of the status of the oral cavity. To this purpose high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI MS) was applied to the analysis of human saliva obtained from healthy subjects. All known salivary cystatins, with the exception of cystatin C, were detected. Strong evidence was also obtained for the presence in saliva of post-translational modified isoforms of cystatins, which may be related to donor habits. Cystatin SN and cystatins S, S1 and S2 were well separated by HPLC-ESI MS coupling from other components and thus this approach can be successfully applied to their quantification.

Cres2 and Cres3: new members of the cystatin-related epididymal spermatogenic subgroup of family 2 cystatins

The cystatin-related epididymal spermatogenic (CRES) and recently identified testatin and cystatin T proteins define a new subgroup within the family 2 cystatins of cysteine protease inhibitors. Members of the CRES subgroup are predominantly expressed in reproductive tissues and lack critical cystatin active-site sequences implying divergent functions. To determine whether there are additional members of the subgroup, we searched nucleotide databases and identified two novel genes that we designated Cres2 and Cres3. These genes, like other subgroup members, encode proteins with four conserved cysteine residues and predicted molecular weights characteristic of family 2 cystatins but have divergent cystatin inhibitory sequences. Furthermore, the genes exhibited reproductive-specific expression with Cres2 exclusively expressed in the epithelial cells of the proximal and midcaput epididymal regions and Cres3 expressed in the proximal caput epididymal epithelium, Sertoli cells of the testis, and early follicles and corpora lutea in the ovary. Additional studies showed that, like Cres, both Cres2 and Cres3 genes are dependent on testicular factors for epididymal expression. Taken together, CRES2 and CRES3 represent new members of a subgroup of cystatin family 2 proteins that likely carry out tissue-specific functions distinct from that of typical cystatins.

Expression of cystatins, high molecular weight cytokeratin, and proliferation markers in prostatic adenocarcinoma and hyperplasia

BACKGROUND

Prostatic adenocarcinoma is the most common malignancy among men in the western world but the diagnostic and prognostic criteria for it are still not clearly defined. Additional means for its diagnosis and prognosis are clearly needed. Previously it has been shown that cystatin A is expressed in the basal cells of normal prostate and the expression disappears in prostatic carcinoma.

METHODS

We have now studied the expression of both cystatins A and B in benign prostatic hyperplasias (BPH), prostatic intraepithelial neoplasias (PIN) and carcinomas of the prostatic epithelium and compared it with the expression of high molecular weight (HMW) cytokeratin as well as the proliferation markers cyclin A and Ki-67. The expression of the proteins was immunohistochemically assessed using 33 total prostatectomy specimens.

RESULTS

Cystatin A was expressed in the basal cells in all cases of BPH, low-grade PIN, and high-grade PIN whereas carcinomas showed no staining of cystatin A. The 34 beta E12 cytokeratin expression was similar to basal cystatin A staining and was not seen in carcinoma foci. Cystatin B showed both nuclear and cytoplasmic expression in the columnar epithelial cells. The decrease in median cytoplasmic staining of cystatin B in carcinomas compared to other lesions was significant, but there was a significant increase in expression with dedifferentiation of carcinoma. Also cyclin A and Ki-67 staining were significantly different in non-carcinomatous foci compared to carcinoma foci and had a remarkably similar negative correlations with basal cystatin A and 34 beta E12 staining.

CONCLUSIONS

The results show that cystatin expression can be used as an aid in the diagnosis of prostatic adenocarcinoma and especially cystatin A in the distinction between high grade PIN and grade I carcinoma.

Characterization of IgE responses in a rodent model of filariasis and the allergenic potential of filarial antigens using an in vitro assay

Filarial infections are characterized by high IgE antibody responses. So far, it is not clear whether IgE antibodies are involved in protection, pathology or both. We established a bioassay to detect reactive IgE antibodies in jirds infected with the filaria Acanthocheilonema viteae. Sera of A. viteae-infected jirds were used to sensitize rat basophil leukaemia (RBL) cells and degranulation was stimulated by addition of antigens of A. viteae. Reactive IgE responses were detected from 2 weeks post infection (p.i.) and throughout the A. viteae infection. Male antigen triggered the strongest mediator release, followed by female worms, infective larvae (L3) and microfilariae. Separation of male and female antigen indicated that several antigens of both genders are potent allergens. In particular, one male specific allergen of about 550 kDa induced strongest degranulation of RBL cells. In addition, mediator release stimulated by antigen fractions of about 15 kDa was due to filarial cystatin. In conclusion, we describe a convenient in vitro assay to examine IgE mediated responses in jirds. A sex specific filarial protein with high allergenic potential is identified and cystatin is established as a potent allergen of A. viteae.

Clinical usefulness of cystatin C for the estimation of glomerular filtration rate in type 1 diabetes: reproducibility and accuracy compared with standard measures and iohexol clearance

OBJECTIVE-Assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Plasma creatinine is insensitive for a glomerular filtration rate (GFR) >50 ml/min and creatinine clearance is unwieldy and subject to collection inaccuracies. We aimed to assess the reproducibility, reliability, and accuracy of plasma cystatin C as a measure of GFR ranging from normal to moderate impairment due to type 1 diabetes in the presence of a normal plasma creatinine concentration. RESEARCH DESIGN AND METHODS-A sensitive immunoturbidimetric cystatin C assay was examined in 29 subjects with type 1 diabetes and 11 nondiabetic subjects. Duplicate measurements of the following were collected from each subject, 2 weeks apart: cystatin C, enzymatic plasma creatinine, 24-h creatinine clearance, GFR estimated from plasma creatinine by the Cockcroft-Gault equation, and iohexol clearance as a gold standard. RESULTS-Iohexol clearance ranged from 35 to 132 ml. min(-1). 1.73 m(-2). Plasma cystatin C compared well with the other clinically used tests. The reliability of cystatin C, as assessed by the discriminant ratio, was superior to creatinine clearance (3.4 vs. 1.5, P < 0.001) and the correlation of cystatin C with iohexol clearance (Rs -0.80) was similar to that of creatinine clearance (Rs -0.74) and superior to that of plasma creatinine and the Cockcroft-Gault estimate (Rs -0.54 and 0.66, respectively). Duplicate estimations were used to provide an unbiased equation to convert plasma cystatin C to GFR. CONCLUSIONS-Based on this study, cystatin C is a more reliable measure of GFR than creatinine clearance, is more highly correlated with iohexol clearance than plasma creatinine, and is worthy of further investigation as a clinical measure of GFR in type 1 diabetes.