Kunitz-type trypsin inhibitor prevents LPS-induced increase of cytosolic free Ca2+ in human neutrophils and HUVEC cells

The combination of ulinastatin and somatostatin reduces complication rates in acute pancreatitis: a systematic review and meta-analysis of randomized controlled trials

Currently, there is no specific pharmaceutical agent for treating acute pancreatitis (AP). Somatostatin and its analogues have been used to prevent the autolysis of the pancreas in AP, however, their effectiveness has not been confirmed. This investigation aimed to examine the efficacy of ulinastatin, a protease inhibitor, combined with somatostatin analogues in the treatment of AP. We conducted a systematic database search in 4 databases to identify randomized controlled trials in which the efficacy of ulinastatin in combination with somatostatin analogue was compared to somatostatin analogue alone in patients with AP. Since the patient populations of analysed papers were slightly different, we used random effect models to pool odds ratios (OR) and mean differences (MD) and the corresponding 95% confidence intervals (CI). A total of 9 articles comprising 1037 patients were included in the meta-analysis. The combination therapy significantly reduced the complication rates for acute respiratory distress syndrome, acute kidney injury, and multiple organ dysfunction. Symptoms were relieved threefold with the combination therapy compared to somatostatin alone, and combination therapy significantly shortened the length of hospital stay. The decrease in mortality was not statistically significant..

The Inter-α-Trypsin Inhibitor Family: Versatile Molecules in Biology and Pathology

Inter-α-trypsin inhibitor (IαI) family members are ancient and unique molecules that have evolved over several hundred million years of vertebrate evolution. IαI is a complex containing the proteoglycan bikunin to which heavy chain proteins are covalently attached to the chondroitin sulfate chain. Besides its matrix protective activity through protease inhibitory action, IαI family members interact with extracellular matrix molecules and most notably hyaluronan, inhibit complement, and provide cell regulatory functions. Recent evidence for the diverse roles of the IαI family in both biology and pathology is reviewed and gives insight into their pivotal roles in tissue homeostasis. In addition, the clinical uses of these molecules are explored, such as in the treatment of inflammatory conditions including sepsis and Kawasaki disease, which has recently been associated with severe acute respiratory syndrome coronavirus 2 infection in children.

A Retrospective Analysis of the Cartilage Kunitz Protease Inhibitory Proteins Identifies These as Members of the Inter-α-Trypsin Inhibitor Superfamily with Potential Roles in the Protection of the Articulatory Surface

Aim: The aim of this study was to assess if the ovine articular cartilage serine proteinase inhibitors (SPIs) were related to the Kunitz inter-α-trypsin inhibitor (ITI) family. Methods: Ovine articular cartilage was finely diced and extracted in 6 M urea and SPIs isolated by sequential anion exchange, HA affinity and Sephadex G100 gel permeation chromatography. Selected samples were also subjected to chymotrypsin and concanavalin-A affinity chromatography. Eluant fractions from these isolation steps were monitored for protein and trypsin inhibitory activity. Inhibitory fractions were assessed by affinity blotting using biotinylated trypsin to detect SPIs and by Western blotting using antibodies to α1-microglobulin, bikunin, TSG-6 and 2-B-6 (+) CS epitope generated by chondroitinase-ABC digestion. Results: 2-B-6 (+) positive 250, 220,120, 58 and 36 kDa SPIs were detected. The 58 kDa SPI contained α1-microglobulin, bikunin and chondroitin-4-sulfate stub epitope consistent with an identity of α1-microglobulin-bikunin (AMBP) precursor and was also isolated by concanavalin-A lectin affinity chromatography indicating it had N-glycosylation. Kunitz protease inhibitor (KPI) species of 36, 26, 12 and 6 kDa were autolytically generated by prolonged storage of the 120 and 58 kDa SPIs; chymotrypsin affinity chromatography generated the 6 kDa SPI. KPI domain 1 and 2 SPIs were separated by concanavalin lectin affinity chromatography, domain 1 displayed affinity for this lectin indicating it had N-glycosylation. KPI 1 and 2 displayed potent inhibitory activity against trypsin, chymotrypsin, kallikrein, leucocyte elastase and cathepsin G. Localisation of versican, lubricin and hyaluronan (HA) in the surface regions of articular cartilage represented probable binding sites for the ITI serine proteinase inhibitors (SPIs) which may preserve articulatory properties and joint function. Discussion/Conclusions: The Kunitz SPI proteins synthesised by articular chondrocytes are members of the ITI superfamily. By analogy with other tissues in which these proteins occur we deduce that the cartilage Kunitz SPIs may be multifunctional proteins. Binding of the cartilage Kunitz SPIs to HA may protect this polymer from depolymerisation by free radical damage and may also protect other components in the cartilage surface from proteolytic degradation preserving joint function.

Effect of the urinary tryptin inhibitor ulinastatin on cardiopulmonary bypass-related inflammatory response and clinical outcomes: a meta-analysis of randomized controlled trials

PURPOSE

Cardiopulmonary bypass (CPB) can cause systemic inflammatory responses and a series of subsequent complications that may harm patients. The aim of this study was to explore the effects of ulinastatin on inflammatory responses and clinical outcomes of CPB via a meta-analysis of published randomized controlled trials.

METHODS

A literature search was conducted, both manually and by using the PubMed, EMBASE, Cochrane Library, and Web of Knowledge databases from inception to February 2013, to identify randomized controlled trials. The abstracted efficacy measures included changes in the plasma levels of cytokines (interleukin-6 [IL-6], IL-8, and tumor necrosis factor-α [TNF-α]) measured during the perioperative period and clinical indicators of efficacy, including the duration of mechanical ventilation and the length of intensive care unit stay. Ten ulinastatin-related randomized controlled trials related to cardiac surgeries involving CPB were selected.

FINDINGS

In terms of cytokine concentrations, there were no significant differences between patients who received ulinastatin and those who received placebo before CPB. However, as the surgeries progressed, cytokine concentrations were all significantly lower in the ulinastatin group (P < 0.05 at 1 hour; P < 0.0001 at 6 hours), and the respective plasma concentrations returned to baseline values 24 hours after CPB. In terms of the clinical outcome indices, the length of intensive care unit stay was not significantly different, but the duration of mechanical ventilation (95% CI, -6.75 to -0.39; P = 0.03) was significantly shorter in the ulinastatin group.

IMPLICATIONS

This meta-analysis found that changes in inflammatory cytokines occurred in a time-dependent manner and that the use of ulinastatin resulted in decreased duration of mechanical ventilation with CPB compared with placebo.

Effect of ulinastatin on the expression and distribution of high mobility group box 1 in human colon carcinoma cells in vitro

The aim of the present study was to investigate the in vitro effects of ulinastatin (UTI) on the proliferation, invasion, apoptosis, expression and distribution of high mobility group box 1 (HMGB1) and the expression of nuclear factor κB (NF‑κB) in human colon carcinoma LoVo cells. The cells were divided into control (untreated), UTI1 (400 U/ml UTI), UTI2 (800 U/ml UTI) and UTI3 (1,600 U/ml UTI) groups. The cell proliferation, invasion, apoptosis and the gene and protein expression of HMGB1 and NF‑κB were detected using a tetrazolium assay, Transwell cell invasion assays, a caspase‑3 activity assay, western blot analysis and reverse transcription quantitative polymerase chain reaction, respectively. The distribution of HMGB1 was detected using immunofluorescence. LoVo cell proilferation decreased the most in the UTI3 group followed, in order, by the UTI2, UTI1 and control groups. UTI inhibited invasion in LoVo cells and the inhibitory effect was enhanced as the UTI concentration increased. The activity of caspase‑3 increased the least in the control group followed, in order, by the UTI1, UTI2 and UTI3 groups. UTI inhibited the expression of HMGB1 and NF‑κB, and decreased the cytoplasmic distribution of HMGB1. Thus, UTI inhibited LoVo cell proliferation and induced LoVo cell apoptosis, the mechanism of which may be associated with a decreased in the expression of HMGB1 and NF‑κB, and the cytoplasmic distribution of HMGB1.

Urinary trypsin inhibitor attenuates lipopolysaccharide-induced neutrophil activation

Background

Urinary trypsin inhibitor (UTI), which is speculated to have anti-inflammatory effects, is one of serine protease inhibitors found in human urine and blood. The present study was conducted to clarify the effect of urinary trypsin inhibitor (UTI) on human neutrophil activation and its intracellular signaling mechanism in vitro.

Methods

To assess the possible interactions between UTI and lipopolysaccharide (LPS) in neutrophil activation, neutrophils from human blood were incubated with varying concentrations of UTI (1, 10, 100, 1,000 and 10,000 U/ml) plus LPS (100 ng/ml) or LPS alone in 24-well plates (5 × 10⁶ cells/well). We measured protein levels for interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA) kits after 4 hours of incubation period. To elucidate the intracellular signaling pathway, we also measured the levels of phosphorylation of p38, ERK1/2 and JNK via Western blot analysis. Moreover, the nuclear levels of nuclear factor-kappa B (NF-κB) were determined with electrophoretic mobility shift assays (EMSA).

Results

UTI decreased the expression of inflammatory cytokines, including TNF-α and IL-6, and activation of intracellular signaling pathways, such as JNK, but not P38, ERK1/2 and nuclear translocation of NF-κB.

Conclusions

UTI can attenuate LPS-induced neutrophil responses and may partially contribute to the treatment of neutrophil-mediated inflammatory diseases.

Effects of ulinastatin treatment on myocardial and renal injury in patients undergoing aortic valve replacement with cardiopulmonary bypass

BACKGROUND

We determined the protective effects of a high dose of ulinastatin on myocardial and renal function in patients undergoing aortic valve replacement with cardiopulmonary bypass (CPB).

METHODS

Sixty patients were assigned randomly to either the ulinastatin group (n = 30) or the control group (n = 30). In the ulinastatin group, ulinastatin (300,000 U) was given after the induction of anesthesia, ulinastatin (400,000 U) was added to the CPB pump prime, and then ulinastatin (300,000 U) was administered after weaning from CPB. In the control group, the same volume of saline was administered at the same time points. Creatine kinase-MB levels were assessed 1 day before surgery, and on the first and second postoperative day (POD 1 and 2). Serum creatinine and cystatin C levels were assessed 1 day before surgery, upon intensive care unit arrival, and on POD 1 and 2. The level of plasma neutrophil gelatinase-associated lipocalin was assessed before induction of anesthesia, upon ICU arrival, and on POD 1.

RESULTS

No significant differences were observed in serum levels of creatine kinase-MB and biomarkers of renal injury between the two groups at any point during the study period.

CONCLUSIONS

Ulinastatin showed no cardiac or renal protective effects after CPB in patients undergoing aortic valve replacement.

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.

Effects of ulinastatin treatment on the cardiopulmonary bypass-induced hemodynamic instability and pulmonary dysfunction

OBJECTIVE

To examine the association between decreased release of proinflammatory cytokines in response to urinary trypsin inhibitor pretreatment and decreased myocardial and lung injury after cardiopulmonary bypass.

DESIGN

A prospective, randomized, double-blind study.

SETTING

University hospital.

SUBJECTS

Thirty patients on cardiopulmonary bypass undergoing coronary artery bypass grafting.

INTERVENTIONS

Patients received 5000 units/kg intravenous urinary trypsin inhibitor (n = 15) or 0.9% saline (control, n = 15) immediately before aortic cannulation for cardiopulmonary bypass.

MEASUREMENT AND MAIN RESULTS

Neutrophil elastase, tumor necrosis factor-alpha, interleukin-6, and interleukin-8 were measured after intubation (T1), immediately before aortic cannulation (T2), after separation from cardiopulmonary bypass (T3), at the end of surgery (T4), and on postoperative days 1 (T5), 3 (T6), and 5 (T7). Simultaneous hematocrit values were obtained at all sample times. Isoenzyme of creatine kinase with muscle and brain subunits, troponin-T, and myosin light chain I were also measured. Various hemodynamic and pulmonary data were obtained perioperatively. Levels of neutrophil elastase and cytokines were corrected for hemodilution. Interleukin-6 and interleukin-8 levels were lower at T3 and T4 in the urinary trypsin inhibitor group than in the control group. Stroke volume index was significantly decreased in the control group at T3, and statistical difference was found between groups at T3 (p < .01). Respiratory index and intrapulmonary shunt were significantly higher in the control group than in the urinary trypsin inhibitor group at T3. Changes in respiratory index and intrapulmonary shunt correlated with interleukin-8 levels at T3 (r = .52, p < 00001; r = .37, p < 0001, respectively) and T4 (r = .44, p < .001; r = .24, p < .05, respectively). Neutrophil elastase levels and cardiac marker responses to coronary artery bypass grafting surgery were similar in both groups.

CONCLUSIONS

Prepump administration of urinary trypsin inhibitor attenuates the elevation of interleukin-6 and interleukin-8 release immediately after cardiopulmonary bypass.

Effect of urinary trypsin inhibitor on potassium currents: fetus modulates membrane excitability by production of UTI

BACKGROUND

Amniotic fluid contains a significant level of urinary trypsin inhibitor (UTI). Previously, we reported that UTI inhibits calcium influx of myometrium and it is effective in preventing uterine contraction. This study examined the effects of UTI upon potassium channels, which is important for membrane excitability.

METHODS

Whole-cell patch-clamp recordings were performed in fibroblasts derived from human fetal skin. Potassium currents were recorded and the effects of exogenous UTI and/or cadmium determined.

RESULTS

Tetraethylammonium sensitive potassium currents were elicited by step or ramp stimulations at depolarized membrane potentials (over +30 mV). Administration of 1 micro M UTI significantly increased these potassium currents by 16.9%. When calcium channels were blocked by the administration of cadmium, UTI increased the rest of the potassium currents by 4.8%. This indicates that UTI increased calcium-dependent potassium currents by 94.8% but only increased voltage-dependent potassium currents by 4.8%.

CONCLUSIONS

Urinary trypsin inhibitor is a physiological substance of fetal origin that modulates calcium-dependent and voltage-dependent potassium channels. These data suggest that UTI is capable of regulating the membrane properties of the fetal and myometrial cells in contact with amniotic fluid.

Protective effect of urinary trypsin inhibitor on myocardial mitochondria during hemorrhagic shock and reperfusion

OBJECTIVE

To examine the mitochondrial function in the myocardium after hemorrhagic shock and reperfusion and to evaluate the protective effect of urinary trypsin inhibitor (UTI) on mitochondria.

DESIGN

Animal experiment.

SETTING

University research laboratory.

SUBJECTS

Wistar rats receiving 50,000 units/kg/hr of UTI (n = 27; UTI group) and control rats (n = 26; control group).

INTERVENTIONS

Rats were subjected to low-perfusion ischemia with the left ventricular systolic pressure maintained at 50 mm Hg for 60 mins by bleeding, followed by a 60-min reperfusion by transfusion of shed blood. UTI was infused continuously from 10 mins before bleeding. Cardiac function was measured before bleeding, after bleeding, and after transfusion; at each determination point, the myocardial contents of adenosine triphosphate (ATP), creatine phosphate (P-Cr), pyruvate (Pyr), and lactate (Lac) were measured enzymatically. The cytosolic phosphorylation potential (PP) as well as the redox potential of the oxidized form of nicotinamide adenine dinucleotide/reduced form of nicotinamide adenine dinucleotide couple in mitochondria (Eh(NAD+/NADH)) and change of Gibbs free energy in ATP hydrolysis (deltaG(ATP hydrolysis) energy) were calculated.

MEASUREMENTS AND MAIN RESULTS

Cardiac function decreased during hemorrhagic shock but improved significantly in the UTI group after transfusion compared with the control group. Lac and the Lac/Pyr ratio were significantly lower in the UTI group than in the control group after transfusion. ATP and P-Cr were significantly higher in the UTI group than in the control group after transfusion. PP (x10(3) M-1), Eh(NAD+/NADH) (x - 1 mV), and deltaG(ATP hydrolysis) (x - 1 kcal/mol) were 1.9 +/- 0.4, 266 +/- 4, and 9.7 +/- 0.2, respectively, in the control group and 4.0 +/- 0.9, 274 +/- 5 and 13.0 +/- 0.2, respectively, in the UTI group after transfusion (p <.001, p <.001, and p <.001, respectively).

CONCLUSIONS

In reperfusion after hemorrhagic shock, oxidative phosphorylation in myocardial mitochondria is impaired and energy production remains reduced, even after reperfusion. UTI contributed to the recovery of cardiac function after reperfusion, probably by reducing the severity of mitochondrial dysfunction during a state of shock and by maintaining energy production.

The protease inhibitor bikunin, a novel anti-metastatic agent

Bikunin is a Kunitz-type protease inhibitor predominantly found in human amniotic fluid. In cancers, administration of bikunin may block tumor cell invasion by a direct inhibition of tumor cell-associated plasmin activity as well as by inhibiting urokinase-type plasminogen activator (uPA) expression at the gene and protein levels, possibly through suppression of CD44 dimerization and/or the MAP kinase signaling cascade. Treatment of cancer patients with bikunin may be beneficial in the adjuvant setting to delay the onset of metastasis development and/or in combination with cytotoxic agents to improve treatment efficacy in patients with advanced ovarian cancer.

Suppression of urokinase receptor expression by bikunin is associated with inhibition of upstream targets of extracellular signal-regulated kinase-dependent cascade

Our laboratory showed that bikunin, a Kunitz-type protease inhibitor, suppresses 4beta-phorbol 12-myristate 13-acetate (PMA)- or tumor necrosis factor-alpha (TNFalpha)-induced urokinase-type plasminogen activator (uPA) expression in different cell types. In addition to its effects on protease inhibition, bikunin could be modulating other cellular events associated with the metastatic cascade. To test this hypothesis, we examined whether bikunin was able to suppress the expression of uPA receptor (uPAR) mRNA and protein in a human chondrosarcoma cell line, HCS-2/8, and two human ovarian cancer cell lines, HOC-I and HRA. The present study showed that (a) bikunin suppresses the expression of constitutive and PMA-induced uPAR mRNA and protein in a variety of cell types; (b) an extracellular signal-regulated kinase (ERK) activation system is necessary for the PMA-induced increase in uPAR expression, as PD098059 and U0126, which prevent the activation of MEK1, reduce the uPAR expression; (c) bikunin markedly suppresses PMA-induced phosphorylation of ERK1/2 at the concentration that prevents uPAR expression, but does not reduce total ERK1/2 antigen level; (d) bikunin has no ability to inhibit overexpression of uPAR in cells treated with sodium vanadate; and (e) we further studied the inhibition of uPAR expression by stable transfection of HRA cells with bikunin gene, demonstrating that bikunin secretion is necessary for inhibition of uPAR expression. We conclude that bikunin downregulates constitutive and PMA-stimulated uPAR mRNA and protein possibly through suppression of upstream targets of the ERK-dependent cascade, independent of whether cells were treated with exogenous bikunin or transfected with bikunin gene.

Urinary trypsin inhibitor reduces C-X-C chemokine production in rat liver ischemia/reperfusion

BACKGROUND AND AIM

Protease inhibitors attenuate ischemia/reperfusion injury. However, the underlying mechanisms by which protease inhibitors prevent reperfusion injury remain obscure. Neutrophils play an important role in reperfusion injury. We studied the effects of urinary trypsin inhibitor (UTI) on production of the C-X-C chemokine, cytokine-induced neutrophil chemoattractant (CINC), by Kupffer cells during ischemia/reperfusion of the liver.

METHODS

Liver ischemia was induced in rats by occlusion of the portal vein for 30 min. UTI (50,000 U/kg) was injected intravenously 5 min before vascular clamping. Serum CINC concentrations were measured by enzyme-linked immunosorbent assay. Levels of CINC mRNA in the liver were determined by Northern blot analysis. We also examined the inhibitory effects of UTI on in vitro CINC production by peritoneal macrophages in response to neutrophil elastase (NE).

RESULTS

Serum CINC concentrations increased and peaked 6 h after reperfusion. However, pretreatment of animals with UTI blunted this increase in CINC and significantly reduced CINC mRNA levels in the liver after ischemia/reperfusion. UTI also decreased neutrophil accumulation in the liver 24 h after reperfusion. In vitro CINC production by Kupffer cells from rats pretreated with UTI 3 h after ischemia/reperfusion was significantly decreased compared to those from untreated animals. UTI reduced NE activity in vitro in a dose-dependent manner, and UTI significantly reduced in vitro CINC production by peritoneal macrophages stimulated with NE.

CONCLUSION

UTI reduces the production of CINC by Kupffer cells stimulated with NE, attenuating ischemia/reperfusion injury of the liver.

Therapeutic effects of ulinastatin on experimental crescentic glomerulonephritis in rats

Ulinastatin is a potent protease inhibitor purified from the human urine that has been used clinically to treat acute pancreatitis and circulatory shock. In the current study, we evaluated the therapeutic effects of Ulinastatin in a rat model of crescentic glomerulonephritis (CrGN) and investigated its putative mechanisms. Wistar-Kyoto rats were injected with nephrotoxic serum and received daily intraperitoneal injection of Ulinastatin. Ulinastatin treatment significantly reduced proteinuria and glomerular crescentic formation. Moreover, glomerular infiltration of neutrophils and ED1+ cells (monocytes/macrophages) was significantly suppressed by Ulinastatin. In contrast, the glomerular deposition of heterologous (rabbit) and autologous (rat) antibodies was not changed. Neither serum complement activation nor the anti-rabbit immune response was affected by Ulinastatin administration. Our results suggest that Ulinastatin has preventive effects on rat experimental CrGN, mediated at least in part by inhibiting intraglomerular infiltration of inflammatory cells.

Bikunin--not just a plasma proteinase inhibitor

Bikunin is a plasma proteinase inhibitor that has received little attention in the past, probably because its activity towards various proteinases was found to be relatively weak in early work. It was recently discovered, however, that bikunin effectively inhibits a proteinase that seems to be involved in the metastasis of tumour cells--cell surface plasmin--and that a fragment of bikunin inhibits two proteinases of the coagulation pathway--factor Xa and kallikrein. Furthermore, it has been found that bikunin has other properties, such as the ability to modulate cell growth and to block cellular calcium uptake. Most of the bikunin in the blood occurs as a covalently linked subunit of the proteins pre- and inter-alpha-inhibitor. In this form bikunin lacks some of its known activities, and there is evidence that its release by partial proteolytic degradation may function as a regulatory mechanism. Although the physiological function of bikunin still remains to be established, current data suggest that this protein plays a role in inflammation. Further studies could therefore lead to results of therapeutical value.

The alpha1-microglobulin/bikunin gene: characterization in mouse and evolution

The 129Sv mouse gene coding for the alpha1-microglobulin/bikunin precursor has been isolated and characterized. The 11kb long gene contains ten exons, including six 5'-exons coding for alpha1-microglobulin and four 3'-exons encoding bikunin. Exon 7 also codes for the tribasic tetrapeptide RARR which connects the alpha1-microglobulin and bikunin parts. The sixth intron, which separates the alpha1-microglobulin and bikunin encoding parts, was compared in the human, mouse and a fish (plaice) gene. The size of this intron varies considerably, 6.5, 3.3 and 0.1kb in man, mouse and plaice, respectively. In all three genes, this intron contains A/T-rich regions, and retroposon elements are found in the first two genes. This indicates that this sixth intron is an unstable region and a hotspot for recombinational events, supporting the concept that the alpha1-microglobulin and bikunin parts of this gene are assembled from two ancestral genes. Finally, the nonsynonymous nucleotide substitution rate of the gene was determined by comparing coding sequences from ten vertebrate species. The results indicate that the alpha1-microglobulin part of the gene has evolved faster than the bikunin part.

Identification of structural domains in inter-alpha-trypsin involved in calcium oxalate crystallization

The urinary glycoprotein that inhibits calcium oxalate (CaOx) crystallization in vitro shows a structural similarity to urinary trypsin inhibitor (UTI; recently termed bikunin), the light chain of inter-alpha-trypsin inhibitor (I alpha I). The functional domains of I alpha I involved in its inhibitory activity of CaOx crystallization have been investigated using isolated intact domains of I alpha I produced from controlled proteolytic digests of the protein. The fragments investigated include the heavy chains of I alpha I, UTI, chondroitinase AC-treated UTI, and the carboxyl-terminal domain of UTI (termed HI-8). The effects of I alpha I and its fragments on the inhibitory activity of CaOx crystallization were evaluated in vitro using CaOx crystal aggregation and growth assays, and seeded crystal generation assay as well as using crystal matrix protein generation assay. UTI, but not the heavy chains of I alpha I, had a discernible effect on CaOx crystallization inhibitory activity. Less requirement of the carbohydrate moiety of UTI is implicated by the observation that chondroitinase AC-treated UTI fragment was also found to inhibit CaOx crystallization with almost the same activity as UTI. HI-8 also efficiently inhibited CaOx crystallization, while I alpha I showed a weak inhibitory activity. The results are almost consistent with a seed crystal generation assay and a crystal adsorption inhibition assay, in which I alpha I or its derivatives inhibits prothrombin fragment 1 (F1) adsorption to CaOx crystals. In conclusion, these results suggest that the part of the I alpha I protein responsible for inhibition of CaOx crystallization is the carboxyl-terminal domain of UTI.

Urinary trypsin inhibitor reduces the release of histamine from rat peritoneal mast cells

We determined the ability of urinary trypsin inhibitor (UTI), which is a Kunitz-type protease inhibitor present in serum and in urine, to inhibit rat peritoneal mast cell (RPMC) mediator release induced by several stimuli. UTI attenuated the immunoglobulin E-mediated release of both preformed (histamine) and newly formed (leukotriene C4) mediators from RPMCs. Inhibition (21%+/-5%) of the anti-IgE-triggered release of histamine was observed after a 30-minute incubation of RPMCs with UTI (5 micromol/L). To investigate the specificity of the UTI effect, we studied the stimulatory activity of phorbol ester (phorbol 12-myristate 13-acetate (PMA)) or calcium ionophore A23187 in control and UTI-treated mast cells. The efficacy of UTI as an inhibitor was dependent on the nature of the stimulus, because histamine release induced by PMA-mediated or calcium ionophore A23187-mediated processes was not inhibited by UTI. A series of structurally distinct protease inhibitors did not inhibit IgE-induced release of mediators from RPMCs. The Kunitz-type protease inhibitors are important in the regulation of RPMC function. In parallel with the UTI-related decrease in anti-IgE stimulatory activity on mediator release, increased microviscosity of membrane lipids could be observed by two independent experiments on fluorescence polarization with diphenylhexatriene (DPH) and on the fluorescence probe fluorescein isothiocyanate-concanavalin A. UTI reduces mediator release by a mechanism-possibly an interruption of the coupling of receptor and effector systems-because UTI acts as an agent to decrease biologic lipid membrane fluidity.

Urinary trypsin inhibitor suppresses the production of interstitial procollagenase/proMMP-1 and prostromelysin 1/proMMP-3 in human uterine cervical fibroblasts and chorionic cells

The mechanisms by which urinary trypsin inhibitor (UTI) prevents preterm premature rupture of fetal membrane and premature cervical ripening were investigated. We, therefore, examined the effects of UTI on the production of matrix metalloproteinases (MMPs) which closely participate in the breakdown of extracellular matrix in cultured human uterine cervical fibroblasts and human chorionic cells. UTI suppressed specifically the production of interstitial procollagenase/proMMP-1 and prostromelysin 1/proMMP-3 from both cells in a dose-dependent manner (0.32-1.28 microM). This suppression was accompanied by a decrease in steady-state levels of their mRNAs. These results indicate for the first time that UTI down-regulates the production of proMMP-1 and proMMP-3 accompanying with the decrease in the expression of their mRNAs, and therefore UTI actually participates in the maintenance of fetal membranes and/or uterine cervix by overall suppression of MMP production along with the known inhibitory actions towards serine proteinases.

Increase of bikunin and alpha1-microglobulin concentrations in urine of rats during pregnancy is due to decreased tubular reabsorption

Bikunin and alpha1-microglobulin are two plasma proteins of about 25 kDa which are made in the liver from a common precursor. The concentration of bikunin in human urine has been shown to increase several fold during various conditions of stress. The mechanism behind this increase is unknown. We have studied pregnant rats and found that the bikunin and alpha1-microglobulin levels in their urine increased 3-fold towards the end of the pregnancy, whereas those of albumin and orosomucoid did not. There were no significant changes in either the bikunin/alpha1-microglobulin mRNA level or the concentrations of the two proteins in serum. These findings imply that the synthesis and the clearance rates of bikunin and alpha1-microglobulin are normal during pregnancy but that the tubular reabsorption of these proteins is decreased.

Secretory leukocyte protease inhibitor: a macrophage product induced by and antagonistic to bacterial lipopolysaccharide

To explore regulation of potentially lethal responses to bacterial lipopolysaccharide (LPS), we used differential display under LPS-free conditions to compare macrophage cell lines from two strains of mice congenic for a locus affecting LPS sensitivity. LPS-hyporesponsive cells, primary macrophages, and polymorphonuclear leukocytes transcribed secretory leukocyte protease inhibitor (SLPI), a known epithelial cell-derived inhibitor of leukocyte serine proteases. Transfection of macrophages with SLPI suppressed LPS-induced activation of NF-kappa B and production of nitric oxide and TNF alpha. The ability of interferon-gamma (IFN gamma) to restore LPS responsiveness is a hallmark of the LPS-hyporesponsive phenotype. IFN gamma suppressed expression of SLPI and restored LPS responsiveness to SLPI-producing cells. Thus, SLPI is an LPS-induced IFN gamma-suppressible phagocyte product that serves to inhibit LPS responses.