[Mechanism of action of factor XIII].
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We report a novel mutation in factor XIIIA gene that caused severe congenital factor XIII deficiency in a 6 year and 8 month old male. The mutation is a GA deletion in the core domain leading to a premature stop at codon 502. The child had severe deficiency with two episodes of intracerebral hemorrhage. He also developed spontaneous splenic rupture, an unusual complication of this disorder.
Factor XIII (FXIII) links soluble fibrin monomers and collagen fibres to stable fibrin connections. Deficiency of FXIII, caused by dyspoiesis or increased consumption, results in a bleeding tendency and wound healing complications. Although the decrease of FXIII and successful replacement in patients with wound healing complications after surgery have been described by several authors, it is rarely considered that patients with autoimmune diseases, bleeding or healing complications may suffer from FXIII deficiency. We report a patient with severe psoriasis vulgaris generalisata with large, painful erythemas, bleeding tendency, joint contractions and infirmity, whose FXIII activity was 19%. After successful replacement the bleeding tendency vanished, and a marked improvement of skin and joint mobility allowed mobilisation and administration of physical therapy, whereby some independence and mobility were restored to the patient.
Two Japanese patients were newly diagnosed as having B subunit (XIIIB) deficiency of factor XIII (former type I deficiency). Both patients have a previously described one-base deletion at the boundary between intron A/exon II in the XIIIB gene, heterozygously or homozygously. A founder effect was proposed for this mutation because 3 unrelated patients with XIIIB deficiency also share 2 3'-polymorphisms. In one patient heterozygous for the above mutation, a novel mutation was also identified: a deletion of guanosine in exon IX (delG) of the XIIIB gene. To understand the molecular and cellular pathology of the delG mutation, expression studies were performed using a cultured mammalian cell line. Pulse-chase experiments showed that a resultant truncated XIIIB remained inside the cells and could not be secreted into the culture medium. Furthermore, immunocytochemical examinations by epifluorescence, confocal, and electron microscopes indicated impaired intracellular transportation of the truncated XIIIB from the endoplasmic reticulum to the Golgi apparatus. No mutations in the gene for the A subunit (XIIIA) were identified in this patient. Therefore, secretion of the truncated XIIIB must also be impaired in vivo, leading to a secondary XIIIA deficiency. These results support a previous conclusion that genetic defects of XIIIB are the basis for the former type I factor XIII deficiency.
BACKGROUND: Blood coagulation factor XIII (FXIII) is a zymogen that is transformed into an active transglutaminase by thrombin and Ca(2+). FXIII plays an essential role in fibrin stabilization and in the protection of fibrin from proteolytic degradation. No convenient method has been available for the measurement of FXIII activity in plasma. The aim of the present study was to improve and optimize a kinetic photometric FXIII assay originally developed in our laboratory. METHODS: In the assay, FXIII was activated by thrombin and Ca(2+). Fibrin polymerization was prevented by an inhibitory tetrapeptide. Glycine-ethyl ester and a glutamine residue of a synthetic dodecapeptide served as acyl acceptor and acyl donor transglutaminase substrates, respectively. The amount of ammonia released during the reaction was monitored using glutamate dehydrogenase and NADPH. RESULTS: The use of a new glutamine substrate and optimization of activator and substrate concentrations increased sensitivity. Substitution of NADPH for NADH and introduction of an appropriate blank eliminated systemic overestimation of FXIII activity. The recovery of FXIII was 96%, the assay was linear up to 470 U/L, the detection limit was 1 U/L, and the imprecision (CV) was <8% even at very low FXIII activities. A reference interval of 108-224 U/L (69-143%) was established. The results correlated well with results obtained by an immunoassay specific for plasma FXIII. CONCLUSIONS: The optimized FXIII assay is a simple, rapid method for the diagnosis of inherited or acquired FXIII deficiencies and increased FXIII concentrations. It can be easily adapted to clinical chemistry analyzers.
The plasma factor XIII (FXIII) is a transglutaminase which catalyzes the cross-linking of fibrin monomers during blood coagulation. S-nitrosylation of protein sulfhydryl groups has been shown to regulate protein function. Therefore, to establish whether nitric oxide (NO) affects the enzymatic activity of FXIII, we studied the effect of the NO-donor S-nitroso-N-acetylpenicillamine (SNAP) in a blood coagulation test in vitro. High concentrations of SNAP were found to have inhibitory effects on clot formation. Moreover, specific formation of gamma-dimers through the action of FXIII is selectively inhibited by high concentrations of SNAP, as revealed by Western blot. Purified activated FXIII and plasma preparations were then exposed to NO-donor compounds and the enzyme activity was assayed by measuring the incorporation of [3H] putrescine into dimethylcasein. The NO donors, SNAP, spermine-NO (SPER-NO) and 3-morpholinosydnonimine (SIN-1), and the NO-carrier, S-nitrosoglutathione (GSNO), inhibited FXIII activity in a dose-dependent manner, in both purified enzyme and plasma preparations. Titration of -SH groups of FXIII with [14C] iodoacetamide has shown that the number of titratable cysteines per monomer of FXIII decreased from 1 (in absence of NO donors) to 0 (in the presence of NO donors). These results demonstrate that blood coagulation FXIII is a target for NO both in vitro and in vivo, and that inhibition occurs by S-nitrosylation of a highly reactive cysteine residue. In conclusion, we show that inhibition of FXIII activity by NO may represent an additional regulatory mechanism for the formation of blood clot with physio-pathological implications.
Factor XIII (FXIII) is the plasma-borne transglutaminase involved in fibrin clot stabilization and wound healing. FXIII levels in the plasma of patients with inflammatory bowel diseases are lower than normal and there is a significant inverse correlation of FXIII levels with clinical severity. Moreover, uncontrolled studies report beneficial effects of FXIII supplementation in patients resistant to conventional therapies. We investigated the effects of intravenous recombinant FXIII (rFXIII) treatment in experimentally induced rat colitis to verify that FXIII was the active agent in plasma FXIII concentrates and to better understand the potential therapeutic use of this protein. Colitis was induced by instillation of 12% 2.4,6-trinitrobenzenesulfonic acid (TNBS) in 50% ethanol into the colon of male Wistar rats. Rats were treated with 0.65 mg/kg rFXIII or vehicle (intravenously) daily for 10 days. Treatment was started either immediately after TNBS/EtOH instillation (to evaluate effects on developing lesions) or seven days later (to evaluate effects on established lesions). In both cases rats were killed either immediately after the end of treatment (to evaluate immediate effects) or 17 days later (to evaluate long-lasting effects). The effects of rFXIII were compared to positive (5-amino-2-hydroxybenzoic acid) control over a 35-day time course. The severity of lesions was determined by colon weight and macroscopic and histologic scores. Transglutaminase activity was measured in both colon tissue and serum. rFXIII treatment reduced lesion severity significantly not only in developing but also in established lesions. Improvements in healing persisted at least 18 days after treatment was discontinued. Serum and tissue transglutaminase levels were restored by rFXIII treatment. In conclusion, pure rFXIII is as effective as plasma FXIII concentrates in a rat model of experimental colitis. In addition, rFXIII significantly improves the healing of preexisting lesions, a characteristic useful in treatment of human inflammatory bowel diseases.
Several diseases show an impairment of vascular barrier function. In the past, we found out that topically applied plasmatic factor XIII distinctly reduced secretion tendency and improved granulation in venous ulcer. Increased vascular permeability is also discussed in patients with a long lasting diabetic status being a relevant cause of impaired local wound healing. Therefore, we introduced the topical application of factor XIII into the therapy of diabetic foot ulcer. After basic experimental investigations revealed that factor XIII significantly reduces endothelial permeability of cultured endothelial cells, the first clinically treated diabetic patients showed encouraging results, too.
Factor FXIII (FXIII) is a plasma transglutaminase that catalyzes the cross link formation between fibrin chains to stabilize the clot. Beside it s function in hemostasis FXIII has a role in wound healing and embryo implantation--processes that involve angiogenesis. In this review we discuss the role of FXIII in angiogenesis and the molecular mechanisms underlying its pro-angiogenic effect. In addition, FXIII role in wound repair is discussed.
Steady-state kinetic parameters were compared for the action of alpha- and gamma-thrombin on the physiologically important thrombin substrates fibrinogen and factor XIII at 37 degrees C, pH 7.4, and 0.14 M NaCl. gamma-Thrombin, an alpha-thrombin derivative proteolytically cleaved at R-B73 and K-B154, was observed to catalyze the release of fibrinopeptide A (FPA) from fibrinogen with a specificity constant (kcat/Km) of 5 X 10(3) M-1 s-1. This value was approximately 2400-fold lower than the specificity constant for the corresponding alpha-thrombin-catalyzed reaction. The low specificity constant was attributed to an increase in Km and a decrease in kcat for gamma-thrombin-catalyzed release of FPA from fibrinogen. Conversion of alpha-thrombin to gamma-thrombin also resulted in an approximately 800-fold reduction in the specificity constant for thrombin-catalyzed release of fibrinopeptide B (FPB) from fibrin I, as well as a loss in discriminatory power. Whereas alpha-thrombin preferentially released FPA from intact fibrinogen, gamma-thrombin released FPA and FPB from intact fibrinogen at similar rates. In contrast to the large difference in specificity constants observed for alpha- and gamma-thrombin catalysis with fibrin(ogen) as substrate, the specificity constant (2.6 X 10(4) M-1 s-1) observed for gamma-thrombin-catalyzed release of activation peptide from factor XIII was only 5-fold lower than the corresponding value for the alpha-thrombin-catalyzed reaction. Additionally, the promotion of factor XIII activation by fibrin characteristic of the alpha-thrombin-catalyzed reaction did not occur in the gamma-thrombin-catalyzed reaction.(ABSTRACT TRUNCATED AT 250 WORDS)
A role of factor XIII (FXIII) on the interaction of human platelets with collagen was investigated using either formaldehyde fixed-washed platelets (FWP) or nonfixed platelets. The adhesion of FWP to bovine type I collagen was measured by using either an aggregometer or a collagen immobilized glass beads column. The interaction of non-fixed human platelets with collagen was measured with in vitro bleeding time (Thrombostat-4,000), which was performed by passing citrated whole blood through the filter covered with rat type I collagen under the constant shear stress. FWP adhesion to the collagen immobilized column (1,300 micrograms collagen) was not changed by the addition of commercial FXIII preparation (Fibrogammin); the adhesion was 42.7% in the presence of 1% human serum albumin, 42-43% in the presence of 1-2 U/ml of FXIII. The addition of rabbit antibody to FXIII to normal FWP did not change the degree of adhesion; 42.3% (1:100 anti-FXIII) and 46.1% (normal rabbit serum). Furthermore, platelets from the patient with congenital FXIII deficiency normally aggregated by bovine collagen and the adhesion of the patient FWP to the collagen was similar to that of normal FWP. Prolongation of partial thromboplastin time and the changes of thromboelastograph of normal plasma were observed after mixing with the collagen, and factor VIII, FXIII and von Willebrand factor were adsorbed by the collagen. The amount of FXIII in normal human plasma bound to collagen was 17, 23 and 54% at the concentration of the collagen 250, 500 and 1,000 micrograms/ml, respectively. The binding of plasma ristocetin cofactor was not different between normal control and the patient with FXIII deficiency. These data suggest that FXIII is not involved in human platelet interaction with the type I collagen, while FXIII in normal human plasma binds to the collagen.
There is a wide normal range of coagulation factor XIII activity that has never been adequately explained. A polymorphism substituting leucine for valine at position 34 in the activation peptide of the A subunit of factor XIII has recently been discovered in nondeficient individuals, and the present studies indicate that the leucine substitution results in a significant increase in transglutaminase activity. The frequency of the Leu34 allele in the Australian Caucasian population is 0.27, which is high enough to suggest that the inheritance of either the Val34 or Leu34 alleles may contribute to the wide normal range of activity. Although there has been structural evidence indicating that the activation peptide does not dissociate from the enzyme after thrombin cleavage, the discovery of elevated activity resulting from the Leu34 substitution is the first direct evidence that the activation peptide plays a continuing role in the function of factor XIII.
Factor XIII (FXIII) is a plasma transglutaminase that is essential for normal haemostasis and fibrinolysis. A few polymorphic sites have been identified in the gene, one of them being a point mutation (V34L) in exon 2 of the FXIIIa subunit gene leading to an amino acid change of valine to leucine. We have examined the role of this polymorphism in relation to plasma FXIII activity in a total of 532 healthy individuals belonging to two ethnic groups in Singapore. The frequency of the L34 allele was significantly higher ( P<0.001) among the Asian Indians (0.08) when compared with the Chinese (0.005). No significant difference in frequency of the L34 allele was observed between Asian Indian CAD patients and controls. The mean FXIII levels were significantly higher ( P<0.0005) among the Asian Indians (148.4%+/-35.5) when compared with Chinese (111.2%+/-26.7). The L34 variant was associated with increased FXIII activity among Asian Indian females. This study shows that both racial and genetic components play a significant role in determining plasma FXIII activity. The effect of V34L polymorphism on FXIII activity in the Indian females is independent of the effects of the P564L and E651Q polymorphic sites in the FXIIIa gene.
Modern views on the functioning of coagulation system are constantly replenished with the facts obtained using the newest methods of molecular biology and medicine. The purpose of many components of this system is non-uniform and covers the whole spectrum of biochemical reactions responsible for homeostasis. Current data on one of such components--the factor XIII (fibrin stabilizing factor) are stated. Except for the description of the enzyme structure and functions, information is presented about the methods of its detection, which development has resulted in accumulation of knowledge on the role of fibrin stabilizing factor in bleedings and thrombosis genesis. Data are given on hereditary and acquired deficiency of the factor XIII, as well as on conditions accompanied with the increase of its activity.
A high-performance liquid chromatographic method was developed for the assay of transglutaminase [EC 2.3.2.13] activity. Casein and dansylcadaverine were used as substrates and the reaction was stopped by adding an excess amount of EGTA. Casein-bound dansylcadaverine was separated from free dansylcadaverine by high-performance liquid chromatography on a TSK SW gel column on the basis of the differences in the molecular weight and hydrophobicity. The sensitivity was approximately 0.04 nmol of casein-bound dansylcadaverine in the assay mixture. With this assay method, human erythrocyte transglutaminase and platelet factor XIII were purified by successive chromatographies on DEAE-cellulose and Sephacryl S-300, which were common for both enzymes, followed by Blue Sepharose CL-6B and DEAE Bio-Gel A for erythrocyte transglutaminase or Phenyl-Sepharose CL-4B for platelet factor XIII. The purification factors and activity yields were 15,300-fold and 22% for erythrocyte transglutaminase and 43.8-fold and 33% for platelet factor XIII.
Blood coagulation factor XIII (FXIII) plays an important role in the final stage of the blood coagulation process. Thrombelastography (TEG) enables global assessment of the hemostatic function. The present study tested for the first time the specificity and sensitivity of the rotation thrombelastography (ROTEG: rotation thrombelastography) method for the influence of FXIII and the FXIIIVal34Leu polymorphism on thrombelastograms measured in citrated plasma. Three thrombelastographic parameters were determined in (a) citrated pool plasma, (b) FXIII-deficient plasma, (c) different mixtures of both, and (d) in 60 plasma samples genotyped for FXIIIVal34Leu. Thrombelastograms from FXIII-deficient plasma were significantly smaller than those from pool plasma (8 mm vs. 20.9 mm). Increasing amounts of pool plasma added to FXIII-deficient plasma led to an increase in maximum clot firmness (MCF). FXIIIVal34Leu showed an influence on clot formation time (CFT) values, which decreased with increasing number of Leu alleles. The difference between the wild type and the homozygote mutant genotype was statistically significant (median 185.3 vs. 86.0 s, P=.031). ROTEG is a simple but effective method for the investigation of FXIII function in plasma. The ROTEG method has shown to be not only specific for the FXIII influence, as effects exclusively dependent on FXIII could be observed, but also sensitive, as already smallest amounts of FXIII could be detected. Additionally, the impact of a common genetic polymorphism on ROTEG could be shown for the first time.
A study of factor XIII A-subunit has been made by electrospray ionisation mass spectrometry. Factor XIII has been isolated and rigorously purified, and the intact A-subunit protein has been analysed to confirm its molecular weight accurately for the first time. Thrombin proteolysis of the A-subunit has been monitored and the resulting cleavage products, the activated A-subunit protein and the Activation Peptide, have been analysed by electrospray ionisation mass spectrometry to confirm the site of proteolysis. Facile and rapid separation of the Activation Peptide from the activated A-subunit protein has been achieved using simple on-line separation techniques. The molecular weight measurements have been repeated numerous times to provide an indication of the precision and variability of the analyses.
Chronic changes in blood flow induce an adaptation of vascular caliber. Thus, arteries show inward remodeling after a reduction in blood flow. We hypothesized that this remodeling depends on the crosslinking enzyme tissue-type transglutaminase (tTG). Flow-dependent remodeling was studied in wild-type (WT) and tTG-null mice using a surgically imposed change in blood flow in small mesenteric arteries. WT mice showed inward remodeling after 2 days of low blood flow, which was absent in arteries from tTG-null mice. Yet, after continued low blood flow for 7 days, inward remodeling was similar in arteries from WT and tTG-null mice. Studying the alternative pathways of remodeling, we identified a relatively high expression of the plasma transglutaminase factor XIII in arteries of WT and tTG-null mice. In addition, vessels from both WT and tTG-null mice showed the presence of transglutaminase-specific crosslinks. An accumulation of adventitial monocytes/macrophages was found in vessels exposed to low blood flow in tTG-null mice. Because monocytes/macrophages may represent a source of factor XIII, tTG-null mice were treated with liposome-encapsulated clodronate. Elimination of monocytes/macrophages with liposome-encapsulated clodronate reduced both the expression of factor XIII and inward remodeling in tTG-null mice. In conclusion, tTG plays an important role in the inward remodeling of small arteries associated with decreased blood flow. Adventitial monocytes/macrophages are a source of factor XIII in tTG-null mice and contribute to an alternative, delayed mechanism of inward remodeling when tTG is absent.