Role of O-linked carbohydrate of human urinary trypsin inhibitor on its lysosomal membrane-stabilizing property

Molecular and pathobiological insights of bikunin/UTI in cancer

Bikunin is a small chondroitin sulfate proteoglycan (PG) with Ser-protease inhibitory activity that plays pleiotropic roles in health and disease. It is involved in several physiological processes including stabilization of the extracellular matrix (ECM) of connective tissues and key reproductive events. Bikunin is also implicated in both acute and chronic inflammatory conditions and represents a non-invasive circulating and/or urinary (as Urinary Trypsin Inhibitor or UTI) biomarker. It exerts inhibitory effects on urokinase-type plasminogen activator (uPA) and its receptor (uPAR) mediating tumor invasiveness by a down-regulation of uPA mRNA expression, thus representing an anti-metastatic agent. However, only limited data on its potential as a diagnostic and/or prognostic marker of cancer have been reported so far. Recent technological advances in mass spectrometry-based proteomics have provided researchers with a huge amount of information allowing for large-scale surveys of the cancer proteome. To address such issues, we analyzed bikunin expression data across several types of tumors, by using UALCAN proteogenomic analysis portal. In this article we critically review the roles of bikunin in human pathobiology, with a special focus on its inhibitory effects and mechanisms in cancer aggressiveness as well as its significance as cancer circulating biomarker.

Role of the small proteoglycan bikunin in human reproduction

PURPOSE

Female reproductive events, including ovulation, menstruation, implantation, and delivery, are physiologically characterized by deep tissue remodeling and display hallmark signs of inflammation. This review discusses the pleiotropic roles played by bikunin in human reproduction.

METHODS

A comprehensive literature search of the Medline/PubMed database was performed on the following topics: bikunin structure, roles in pathophysiological conditions and involvement in human reproduction, and usefulness as a marker of gestational complications or as a drug to improve pregnancy outcomes.

RESULTS

Bikunin is a small chondroitin sulfate proteoglycan found in blood, urine, and amniotic and cerebrospinal fluids, known for its anti-inflammatory and anti-proteolytic activities. Its levels are usually low, but they can increase several-fold in both acute and chronic inflammatory diseases. Bikunin plays key roles in reproductive events, such as cumulus-oocyte complex formation, pregnancy, and delivery. Its levels have been associated with the most common pregnancy complications such as preterm delivery, pre-eclampsia, and gestational diabetes mellitus. Finally, its intravaginal administration has been reported to reduce the risk of preterm delivery and to improve neonatal outcomes.

CONCLUSIONS

Because of its pleiotropic roles in several reproductive events and its association with some life-threatening pathological conditions of pregnancy, bikunin may represent a non-invasive marker for improving follow-up and early diagnosis. Studies showing its usefulness as a drug for reducing the risk of preterm delivery and improving neonatal outcomes have yielded interesting results that deserve to be investigated through further research.

Proteomic identification of hippocalcin and its protective role in heatstroke-induced hypothalamic injury in mice

Heatstroke is a devastating condition that is characterized by severe hyperthermia and central nervous system dysfunction. However, the mechanism of thermoregulatory center dysfunction of the hypothalamus in heatstroke is unclear. In this study, we established a heatstroke mouse model and a heat-stressed neuronal cellular model on the pheochromocytoma-12 (PC12) cell line. These models revealed that HS promoted obvious neuronal injury in the hypothalamus, with high pathological scores. In addition, PC12 cell apoptosis was evident by decreased cell viability, increased caspase-3 activity, and high apoptosis rates. Furthermore, 14 differentially expressed proteins in the hypothalamus were analyzed by fluorescence two-dimensional difference gel electrophoresis and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Expression changes in hippocalcin (HPAC), a downregulated neuron-specific calcium-binding protein, were confirmed in the hypothalamus of the heatstroke mice and heat-stressed PC12 cells by immunochemistry and western blot. Moreover, HPAC overexpression and HPAC-targeted small interfering RNA experiments revealed that HPAC functioned as an antiapoptotic protein in heat-stressed PC12 cells and hypothalamic injury. Lastly, ulinastatin (UTI), a cell-protective drug that is clinically used to treat patients with heatstroke, was used in vitro and in vivo to confirm the role of HPAC; UTI inhibited heat stress (HS)-induced downregulation of HPAC expression, protected hypothalamic neurons and PC12 cells from HS-induced apoptosis and increased heat tolerance in the heatstroke animals. In summary, our study has uncovered and demonstrated the protective role of HPAC in heatstroke-induced hypothalamic injury in mice.

Ulinastatin Inhibits Osteoclastogenesis and Suppresses Ovariectomy-Induced Bone Loss by Downregulating uPAR

Recent studies indicate that uPAR acts a crucial part in cell migration and the modulation of bone homeostasis. As a natural serine protease inhibitor, ulinastatin owns the capacity to reduce proinflammatory factors, downregulate the activation of NF-κB and mitogen-activated protein kinases (MAPKs) signaling pathways. Osteoclastogenesis has been demonstrated to be related with low-grade inflammation which involves cell migration, thus we speculate that ulinastatin may have a certain kind of impact on uPAR so as to be a potential inhibiting agent of osteoclastogenesis. In this research, we investigated the role which ulinastatin plays in RANKL-induced osteoclastogenesis both in vivo and in vitro. Ulinastatin inhibited osteoclast formation and bone resorption in a dose-dependent manner in primary bone marrow-derived macrophages (BMMs), and knockdown of uPAR could completely repress the formation of osteoclasts. At the molecular level, ulinastatin suppressed RANKL-induced activation of cathepsin K, TRAP, nuclear factor-κB (NF-κB) and MAPKs, and decreased the expression of uPAR. At the meantime, ulinastatin also decreased the expression of osteoclast marker genes, including cathepsin K, TRAP, RANK, and NFATc1. Besides, ulinastatin prevented bone loss in ovariectomized C57 mice by inhibiting the formation of osteoclasts. To sum up, this research confirmed that ulinastatin has the ability to inhibit osteoclastogenesis and prevent bone loss, and uPAR plays a crucial role in that process. Therefore, ulinastatin could be chosen as an effective alternative therapeutics for osteoclast-related diseases.

Levels of Urinary Trypsin Inhibitor and Structure of Its Chondroitin Sulphate Moiety in Type 1 and Type 2 Diabetes

BACKGROUND

Diabetes mellitus is a global health problem representing the fifth leading cause of mortality and a major risk factor for cardiovascular diseases. In the last years, we reported an association among urinary trypsin inhibitor (UTI), a small proteoglycan that plays pleiotropic roles in many inflammatory processes, and both type 1 and 2 diabetes and developed a method for its direct quantitation and structural characterization.

METHODS

Urine from 39 patients affected by type 1 diabetes, 32 patients with type 2 diabetes, and 52 controls were analysed. UTI was separated from the main glycosaminoglycans physiologically present in urine by anion exchange chromatography, treated for chondroitin sulphate (CS) chain complete depolymerisation, and analysed for both UTI content and CS structure. UTI identification was performed by nano-LC-MS/MS analysis.

RESULTS

We evidenced increased UTI levels, as well as reduced sulphation of its CS moiety in association with diabetes, regardless of both age and medium-term glycaemic control. Furthermore, no association between UTI and albumin excretion rate was found.

CONCLUSIONS

Evidences suggest that UTI levels are not directly correlated with renal function or, otherwise, that they may increase before the onset of renal impairment in diabetes, representing a potential marker for the underlying inflammatory condition.

Cryptdin-2 predicts intestinal injury during heatstroke in mice

Intestinal injury-induced bacterial translocation and endotoxemia are important in the pathophysiological process of heatstroke. However, the underlying mechanism remains to be fully elucidated. Previous studies using 2D-gel electrophoresis found that defensin-related cryptdin-2 (Cry-2), an intestinal α-defensin, is upregulated in intestinal tissues during heatstroke in mice, and that treatment with ulinastatin, a multivalent enzyme inhibitor, reduced heat-induced acute lung injury. To investigate the association between Cry-2 and heat stress (HS)-induced intestinal injury and the probable protective role of ulinastatin, the present study examined the intestinal expression of Cry-2 via histopathologic analysis and reverse transcription-quantitative polymerase chain reaction analysis in mice with heatstroke. The heat-stressed mice were exposed to different core temperatures and cooling treatments, and intestinal pathological changes and Chiu scores were determined. Chemical markers of intestinal injury, serum and intestinal concentrations of diamine oxidase (DAO) and D-lactic acid (D-Lac), and serum and intestinal concentrations of Cry-2 were also determined. Correlations were analyzed using Spearman's correlation analysis. It was found that HS upregulated the expression of Cry-2, and the serum and intestinal concentrations of Cry-2 were correlated with the severity of HS-induced intestinal damage, indicated by pathology scores and concentrations of DAO and D-lac. Ulinastatin protected the intestines from HS-induced injury and downregulated the expression of Cry-2, which was also correlated with the extent of intestinal injury. Therefore, ulinastatin administration may be beneficial for patients with heatstroke, and Cry-2 may be a novel predictor of HS-induced intestinal injury.

Significance of urinary glycosaminoglycans/proteoglycans in the evaluation of type 1 and type 2 diabetes complications

Because of the high incidence of kidney disease in diabetic patients, the early diagnosis of renal impairment is a key point for intervention and management. Although urinary albumin excretion currently represents the accepted standard to assess both diabetic nephropathy and cardiovascular risk, it has some limitations as structural changes in the glomerular basement membrane may occur before the onset of microalbuminuria. It is therefore important to identify urinary markers that may provide greater sensitivity, earlier detection, and greater predictive power for diabetes complications. In this respect, urinary glycosaminoglycans/proteoglycans (GAGs/PGs) have been long associated with several kidney diseases as well as diabetic nephropathies as their levels increase more readily than albuminuria. In particular, heparan sulfate, a key component of the glomerular basement membrane responsible for its charge-dependent permeability, is excreted into urine at higher concentrations during the early kidney remodeling events caused by the altered glucose metabolism in diabetes. Over the past few years, also urinary trypsin inhibitor has been linked to a chronic inflammatory condition in both type 1 and 2 diabetes. The underlying mechanisms of such increase are not completely known since either a systemic inflammatory condition or a more localized early renal impairment could play a role. Nevertheless, the association with other inflammatory markers and a detailed urinary trypsin inhibitor structural characterization in diabetes remain to be elucidated. This review will discuss a great deal of information on the association between urinary GAGs/PGs and type 1 and 2 diabetes, with particular emphasis on renal involvement, and their potential as markers useful in screening, diagnosis and follow up to be associated with the current standard tests.

Enzymatic synthesis of hyaluronan hybrid urinary trypsin inhibitor

Human urinary trypsin inhibitor is a proteoglycan that has a single low-sulfated chondroitin 4-sulfate chain at the seryl residue in position 10 of the core protein as a glycosaminoglycan moiety, and is used as an anti-inflammatory medicine based on the protease inhibitory activity of the core protein. However, the functions of the glycosaminoglycan moiety have not yet been elucidated in detail. In the present study, the glycosaminoglycan chains of a native urinary trypsin inhibitor were remodeled to hyaluronan chains, with no changes to the core protein, using transglycosylation as a reverse reaction of the hydrolysis of bovine testicular hyaluronidase, and the properties of the hybrid urinary trypsin inhibitor were then analyzed. The trypsin inhibitory activitiy of the hyaluronan hybrid urinary trypsin inhibitor was similar to that of the native type; however, its inhibitory effect on the hydrolysis of hyaluronidase were not as strong as that of the native type. This result demonstrated that the native urinary trypsin inhibitor possessed hyaluronidase inhibitory activity on its chondroitin sulfate chain. The hyaluronan hybrid urinary trypsin inhibitors obtained affinity to a hyaluronan-binding protein not exhibited by the native type. The interactions between the hyaluronan hybrid urinary trypsin inhibitors and phosphatidylcholine (abundant in the outer layer of plasma membrane) were stronger than that of the native type. Hyaluronan hybrid urinary trypsin inhibitors may be useful for investigating the functions of the glycosaminoglycan chains of urinary trypsin inhibitors and hyaluronan, and our hybrid synthesizing method may be used widely in research for future medical applications.

Preventive effect of urinary trypsin inhibitor on the development of liver fibrosis in mice

Urinary trypsin inhibitor (UTI) is a serine protease inhibitor produced in the liver that inhibits the production and activation of various cytokines, notably transforming growth factor-β (TGF-β), which are associated with the progression of liver fibrosis. However, the various roles of endogenous UTI in liver fibrosis have not been examined. This study, therefore, examined the long-term effects of UTI deficiency during both steady-state conditions and thioacetamide (TA)-induced liver fibrosis. Furthermore, the effects of continuous exogenous UTI administration were examined. Analyses of liver fibrosis marker, hyaluronic acid (HA), TGF-β concentrations and histological findings at 30 weeks of age showed that homozygous UTI-knockout (KO) mice had higher HA and TGF-β concentrations than did heterozygous UTI-KO mice and wild-type mice, although there was no histological evidence of liver fibrosis in these mice. TA treatment for 20 weeks also resulted in greater HA and TGF-β levels in homozygous mice than in heterozygous and wild-type mice. Furthermore, homozygous mice had more severe liver fibrosis based on histological analyses. HA and TGF-β levels were lower in homozygous UTI-KO mice that were continuously administered UTI versus those given distilled water. These findings indicate that UTI deficiency leads to the production of HA and hepatic TGF-β and that administering exogenous UTI can ameliorate these changes. We conclude that endogenous UTI is produced in the liver to suppress the production and activation of TGF-β and that administering exogenous UTI may be therapeutically beneficial for preventing liver fibrosis.

Molecular structure and function analysis of bikunin on down-regulation of tumor necrosis factor-alpha expression in activated neutrophils

OBJECTIVE

We performed a detailed molecular analysis of bikunin-mediated anti-inflammation (suppressive effect of cytokine release, MAP kinase activation, and nuclear translocation of NF-kB) using a truncated form of bikunin.

MATERIALS AND METHODS

We obtained bikunin derivatives that contained O-glycoside-linked N-terminal glycopeptide (Bik-m1), N-glycoside-linked C-terminal tandem Kunitz domains (Bik-m2), bikunin lacking O-glycoside (Bik-c), asialo bikunin (Bik-a), bikunin lacking N-glycoside (Bik-n), and purified C-terminal Kunitz domain II (kII) of bikunin (HI-8). Enzyme-linked immunosorbent assay and Western blot were carried out to measure secreted TNF-alpha and MAP kinase activation.

RESULTS

We examined the TNF-alpha secretion in control and lipopolysaccharide (LPS)-treated neutrophils and did not see any changes of its protein levels in the cells pretreated with Bik-m1, Bik-m2, Bik-c, or HI-8. In all of the derivatives tested, only the derivatives that lacked N-glycoside side chain showed a significant suppression of TNF-alpha secretion by LPS. Only a small (21 amino acids) deletion of the N-terminal portion of bikunin (which corresponds to Bik-m2) abolished its suppressing activity of TNF-alpha secretion, thus suggesting that the N-terminal 21 amino acids play a critical role in anti-inflammation. Bik-m1 alone failed to show anti-inflammatory response. Bikunin failed to inhibit ionomycin-induced phosphorylation of MAP kinases.

CONCLUSION

These data allow us to conclude that the cytokine expression was inhibited only by the O-glycoside-linked core protein without the N-glycoside side chain. Our results also suggest a possible role of bikunin for receptor-dependent MAP kinase activation.

Immunological evaluation of urinary trypsin inhibitors in blood and urine: role of N- & O-linked glycoproteins

Urinary trypsin inhibitors (uTi) suppress serine proteases during inflammation. After liberation from proinhibitors (P-alpha-I and I-alpha-I) by the white blood cell (WBC) response, uTi readily pass through the kidneys into urine. A key uTi, bikunin, is attached to O-linked and N-linked glycoconjugates. Recently, uTi inhibitors, called uristatins, were found to lack the O-linked glycoconjugates. Monoclonal antibodies were produced using purified uristatin and screened for binding differences to uristatin, bikunin, P-alpha-I, and I-alpha-I. Antibody-binding patterns were characterized using immunoaffinity binding onto protein-chip surfaces and analysis by Surface Enhanced Laser Desorption/Ionization mass spectrometry (SELDI), using specimens from patients and from purified uTi standards. Antibodies were developed and used in an enzyme-linked immunosorbent assay (ELISA) method for uTi measurement in urine and plasma specimens. ELISA was performed on specimens from normal, presumed healthy, controls and from patients who had been screened for inflammation using a high sensitivity C-reactive protein (CRP) test and a complete blood count (CBC). Polyclonal antibody against uTi showed cross-reactivity with the Tamm-Horsfall protein (THP) and with proinhibitors. Screening of anti-uTi monoclonal antibodies (Mab) revealed antibodies that did not cross-react with either of the above, thus providing a tool to measure both uristatin and bikunin in urine with Mab 3G5 and in plasma with Mab 5D11. The monoclonal antibody 5D11 cross-reacts with specific N-linked glycoconjugates of uristatin present in plasma. In ca 96% of healthy adults, uTi were present at <12 mg/l in urine and <4 mg/l in plasma. We also found that patients with an inflammation and a CRP of >2.0 mg/l had higher urinary concentrations of uTi than the control population in every subject. Free uristatin and bikunin pass readily into urine and are primarily bound to heavy chains that constitute the proinhibitor form in plasma.

Bikunin (Urinary Trypsin Inhibitor): Structure, Biological Relevance, And Measurement

Inflammatory processes, such as phagocytosis, coagulation, and vascular dilation, promote the release of serine proteases by neutrophils, macrophages, mast cells, lymphocytes, and the epithelial or endothelial cells. These proteases further facilitate the release of inflammatory cytokines and growth factors as well as take part in signal-cell proliferation through protease-activated receptors (PARs). Controlling the action of this cascade is necessary to prevent further damage to the normal tissues. One of the main anti-inflammatory response mediators is bikunin (Bik) that is responsible for inhibiting the activity of many serine proteases such as trypsin, thrombin, chymotrypsin, kallikrein, plasmin, elastase, cathepsin, Factors IXa, Xa, XIa, and XlIa. During the acute-phase response, Bik is released into plasma from proinhibitors primarily due to increased elastase activity. Bik is a glycoprotein, also referred to as urinary trypsin inhibitor, which in plasma inhibits the trypsin family of serine proteases by binding to either of the two Kunitz-binding domains. Bik also accumulates in urine. In conditions such as infection, cancer, tissue injury during surgery, kidney disease, vascular disease, coagulation, and diabetes, the concentrations of Bik in plasma and urine are increased. Several trypsin inhibitory assays for urine and immunoassays for both blood and urine have been described for measuring Bik. In addition to presenting the synthesis, structure, and pathophysiology of Bik, we will summarize various diagnostic approaches for measuring Bik. Analysis of Bik may provide a rapid approach in assessing various conditions involving the inflammatory processes.

Diversity in the degree of sulfation and chain length of the glycosaminoglycan moiety of urinary trypsin inhibitor isomers

Five isomers with different electric charge were fractionated from human urinary trypsin inhibitor (UTI) by anion exchange HPLC. Intact low-sulfated chondroitin 4-sulfate chains from the isomers were analyzed by HPLC and mass spectrometry. Unsaturated disaccharide composition analysis of the chondroitin sulfate chain revealed that the five isomers differ in the numbers of 4-sulfated disaccharide units. Intriguingly, we detected the presence of multiple novel isomers with different numbers of non-sulfated disaccharide units even in the same charge isomer fraction. Our results demonstrate that UTI can vary in terms of both the degree of sulfation and the length of the low-sulfated chondroitin 4-sulfate chain.

Pathophysiology and diagnostic value of urinary trypsin inhibitors

Inflammation is an important indicator of tissue injury. In the acute form, there is usually accumulation of fluids and plasma components in the affected tissues. Platelet activation and the appearance in blood of abnormally increased numbers of polymorphonucleocytes, lymphocytes, plasma cells and macrophages usually occur. Infectious disorders such as sepsis, meningitis, respiratory infection, urinary tract infection, viral infection, and bacterial infection usually induce an inflammatory response. Chronic inflammation is often associated with diabetes mellitus, acute myocardial infarction, coronary artery disease, kidney diseases, and certain auto-immune disorders, such as rheumatoid arthritis, organ failures and other disorders with an inflammatory component or etiology. The disorder may occur before inflammation is apparent. Markers of inflammation such as C-reactive protein (CRP) and urinary trypsin inhibitors have changed our appraisal of acute events such as myocardial infarction; the infarct may be a response to acute infection and (or) inflammation. We describe here the pathophysiology of an anti-inflammatory agent termed urinary trypsin inhibitor (uTi). It is an important anti-inflammatory substance that is present in urine, blood and all organs. We also describe the anti-inflammatory agent bikunin, a selective inhibitor of serine proteases. The latter are important in modulating inflammatory events and even shutting them down.

Identification of bikunin isolated from human urine inhibits calcium oxalate crystal growth and its localization in the kidneys

BACKGROUND

We previously reported a high molecular weight substance purified from human urine that strongly inhibited calcium oxalate (CaOx) crystal growth in vitro. In the study present herein, we identified and investigated a protein purified from human urine that strongly inhibits CaOx crystal growth using a column chromatography series.

METHODS

The protein was identified by amino acid sequencing and was investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), western blotting and immunohistochemical staining.

RESULTS

The molecular weight of this protein was approximately 35 KDa, and it also had another band around 20 KDa. We determined that the amino acid sequence of the protein was homologous with that of bikunin, the light chain of the inter-alpha-trypsin inhibitor, which is known as a strong CaOx crystallization inhibitor in vitro. On western blotting analysis, the molecular weight was also found to be around 35K Da, the same as that of bikunin. Immunohistochemical staining revealed that it was mainly located in the epithelial cells of the proximal tubules and the thin descending segment near the loop of Henle, but not in the glomeruli, distal tubules or the collecting ducts.

CONCLUSION

In the present study, the protein extracted from human urine was identical to bikunin, which may be expressed mainly in the proximal tubules and the thin descending segment near the loop of Henle, and which prevents CaOx crystallization in vitro.

Plasma and urine levels of urinary trypsin inhibitor in patients with chronic liver diseases and hepatocellular carcinoma

BACKGROUND AND AIM

Because urinary trypsin inhibitor (UTI) is synthesized by hepatocytes and excreted into the urine, plasma and urine levels of UTI may alter in liver diseases. However, there are few reports on the changes in these levels in chronic liver diseases and hepatocellular carcinoma (HCC). The aim of the present study was to evaluate the relationships between plasma and urine UTI levels and the severity of liver damage or progression of HCC in patients with chronic liver diseases and HCC.

METHODS

Plasma and urine UTI levels were measured by a newly developed enzyme-linked immunosorbent assay in 16 patients with chronic hepatitis (CH), 19 patients with liver cirrhosis (LC) and 39 patients with HCC.

RESULTS

Plasma UTI level exhibited a significant positive correlation with the urine UTI level. Plasma and urine UTI levels significantly decreased in LC patients compared with those of normal controls. In contrast, the plasma UTI level in HCC patients was higher than that in LC patients, but there was no difference between the groups in the urine UTI level. Plasma and urine UTI levels in LC and HCC patients were significantly correlated with the degree of liver damage according to the Child-Pugh classification. Although neither the plasma nor urine level of UTI in HCC patients were related to the clinical stage of HCC, both levels were closely associated with the level of protein induced by vitamin K absence or antagonist-II.

CONCLUSIONS

The present findings indicate that the levels of plasma and urine UTI in patients with LC reflect the severity of liver damage. In HCC patients, these levels may also reflect progression of HCC, although further study is required.

Urinary trypsin inhibitor improves peripheral microcirculation and bronchospasm associated with systemic anaphylaxis in rabbits in vivo

Using intravital microscopy of the rabbit ear for quantitative studies of microvascular dynamics, we examined the impact of urinary trypsin inhibitor (UTI), a proteolytic enzyme inhibitor, on microvascular changes during immune complex-mediated anaphylaxis. A total of 50 rabbits, previously sensitized with horse serum, were anesthetized and mechanically ventilated with pentobarbital and isoflurane for the intravital microscopy. Rabbits were then challenged with intravenous injection of horse serum to induce systemic anaphylaxis. One minute after the challenge, each rabbit was randomly assigned to receive saline (group C), 50,000 units x kg(-1) of UTI (group U1), or 150,000 units x kg(-1) (group U2). There were no statistical differences between hemodynamic variables, including heart rate (HR), mean arterial pressure (MAP), and central venous pressure (CVP), among the survivors in each treatment group. Peak inspiratory pressure rose in all three groups but at a much higher rate in group C (P < 0.05). In contrast with the moderate effects of UTI on the above parameters, microscopic evaluation revealed a substantial difference among treatment groups: upon the initiation of anaphylaxis, the arteriole started to reduce in diameter, but UTI prevented vasoconstriction in the arteriole in a dose-dependent manner. Similar results were observed with blood flow velocity. Because flow rate was calculated as the product of blood flow velocity and vascular cross-sectional area proportional to the square of the vessel diameter, these results indicate that UTI preserves microvascular flow rate during anaphylaxis. Rabbit ear microcirculation is highly preserved in the UTI-treated groups during systemic anaphylactic shock.

Plasma and urine levels of urinary trypsin inhibitor in patients with acute and fulminant hepatitis

BACKGROUND AND AIM

Urinary trypsin inhibitor (UTI) is synthesized by hepatocytes and excreted into urine. Plasma and urine UTI levels have been measured to evaluate whether these levels may be useful markers in various pathological conditions. However, there has been no study on plasma and urine UTI levels in patients with acute liver diseases. The aim of the present study was to evaluate plasma and urine UTI levels and their relationship with the severity of hepatic damage in patients with acute liver diseases.

METHODS

Plasma and urine UTI levels were measured by newly developed enzyme-linked immunosorbent assay in 15 patients with acute hepatitis (AH), 12 patients with acute severe hepatitis (ASH) and 10 patients with fulminant hepatitis (FH), as assessed on admission. The serial changes in plasma and urine UTI were also observed in some patients with AH and ASH.

RESULTS

Plasma UTI levels (U/mL, median [25-75th percentile]) were: 11.0, (9.5-16.1) in patients with AH; 7.8 (5.6-11.5) in those with ASH; 6.5 (4.0-9.5) in patients with FH; and 9.7 (7.3-11.0) in normal controls. Plasma UTI levels in patients with FH were significantly lower than in those with AH. Plasma UTI levels showed significant positive correlations with the levels of prothrombin time (PT), hepaplastin test, antithrombin III, alpha2-plasmin inhibitor, plasminogen (Plg) and fibrinogen. After the recovery of liver dysfunction, increased plasma UTI levels in patients with AH were decreased, whereas previously decreased plasma UTI levels in patients with ASH were increased. Urine UTI levels were significantly increased in patients with AH compared with those of normal controls. In patients with ASH and FH, urine UTI levels were increased but not significantly. Urine UTI levels significantly positively correlated with PT and Plg. After the recovery of liver dysfunction, previously increased urine UTI levels in patients with AH were decreased. The correlation between plasma UTI and urine UTI levels was not significant.

CONCLUSIONS

The findings of the present study suggested that the levels of plasma and urine UTI changed in patients with AH and were closely related to the abnormalities of coagulo-fibrinolysis, including PT. Further studies are needed to clarify whether these levels may be useful markers to predict the prognosis of acute hepatitis.

Structure and function analysis of urinary trypsin inhibitor (UTI): identification of binding domains and signaling property of UTI by analysis of truncated proteins

The binding of urinary trypsin inhibitor (UTI) to its binding sites/receptors on tumor cells inhibits cell invasion in a number of experimental systems and that UTI downregulates constitutive and phorbol ester-induced urokinase production by certain tumor cells. To determine whether the carbohydrate moieties and core protein are required for urokinase suppression, we obtained UTI derivatives that contained O-glycoside-linked N-terminal glycopeptide (UTIm1), N-glycoside-linked C-terminal tandem Kunitz domains (UTIm2), UTI lacking O-glycoside (UTIc), asialo UTI (UTIa), UTI lacking N-glycoside (UTIn), purified Kunitz domain II of UTI (HI-8), and recombinant Kunitz domain II of UTI (R-020). The IC(50) of inhibiting binding of (125)I-labeled UTI to cells was indistinguishable for UTIa, UTIn and intact UTI, whereas the IC(50) for inhibiting binding of (125)I-labeled UTI to cells was 2.5-, 25- and 29-fold greater for UTIm1, UTIm2 and UTIc than for native UTI. We next looked at the suppression of the urokinase expression by UTI derivatives. An enzyme-linked immunosorbent assay was carried out to measure secreted and cell-associated urokinase. Intact UTI, UTIa, or UTIn effectively suppressed urokinase expression, but UTIm1, UTIm2, UTIc, HI-8 and R-020 had no significant effect. These data show that UTI requires either the N-terminal extension with the O-linked carbohydrate moiety (chondroitin 4-sulfate sugar side chain; Ala1 to Lys21 residues) or the Kunitz domain I (Lys22 to Arg77 residues) of UTI to bind to cells, but the urokinase expression was inhibited only by the O-glycoside-linked core protein without the N-glycoside side chain.

The chondroitin sulfate chain of bikunin-containing proteins in the inter-alpha-inhibitor family increases in size in inflammatory diseases

Inter-alpha-inhibitor (IalphaI) and pre-alpha-inhibitor (PalphaI) are the main members of a set of multichain serine proteinase inhibitors. Present in human plasma, they may be involved in control of the inflammatory process. They are composed of homologous heavy chains (H1 and H2 for IalphaI; H3 for PalphaI) covalently linked by a protein-glycosaminoglycan-protein cross-link to bikunin, which is a chondroitin 4-sulfate proteoglycan. During the acute-phase response, biosynthesis of IalphaI and PalphaI is downregulated and upregulated, respectively. In this work, we provide evidence that, in inflammatory diseases, the chondroitin sulfate chain of bikunin increases in size proportionally to the severity of the inflammatory response. As a consequence, all IalphaI-related components that contain bikunin are structurally modified. Therefore, the changes in glycosylation of the acute-phase proteins are not restricted to N-linked glycans but also affect glycosaminoglycans. The implications of these findings are discussed with regard to biosynthesis and biological role, especially the anti-inflammatory effects of IalphaI-related proteinase inhibitors.

Calcium-induced changes in chondroitin sulfate chains of urinary trypsin inhibitor

Urinary trypsin inhibitor (UTI) has several roles other than protease inhibition. It is suggested that UTI inhibits calcium influx in cultured cells and that the chondroitin sulfate chain of UTI may play an important role. In order to clarify the mechanistic features of this phenomenon, the chondroitin sulfate chain of UTI was analyzed by (1)H-NMR. The samples were highly purified UTI dissolved in D(2)O in the presence or absence of Ca(2+), Mg(2+) and Na(+). 1D-spectra were obtained and T(1) values of detected signals were estimated from the inversion-recovery method. The addition of Ca(2+) to UTI caused a chemical shift to downfield, line broadening and a reduction of T(1) values at several signals from chondroitin sulfate moiety (especially at axial H-2 of GalNAc), whereas Mg(2+) and Na(+) had no significant effect. Some of the signals in the linkage region of chondroitin sulfate chain showed marked line broadening by Ca(2+). The reduction of T(1) values implies formation of a complex. It is suggested that Ca(2+) generates the sulfate salt and interacts with other polar groups in the chondroitin sulfate chain, thereby causing bridging between UTI molecules. Several properties of UTI may be related to this interaction of Ca(2+) with chondroitin sulfate chains.