Thrombospondin Type-1 Motif Research Articles

Identification of differentially expressed microRNAs in knee anterior cruciate ligament tissues surgically removed from patients with osteoarthritis.

The degradation of cruciate ligaments is frequently observed in degenerative joint diseases, such as osteoarthritis (OA). The present study aimed to identify the differentially expressed microRNAs (miRNAs or miRs) in knee anterior cruciate ligament (ACL) tissues derived from patients with OA and in health subjects (non-OA). By using Affymetrix miRNA 4.0 microarrays, a total of 22 miRNAs (including let-7f-5p, miR-26b-5p and miR-146a-5p) were found to be upregulated, while 17 (including miR-18a-3p, miR-138-5p and miR-485-3p) were downregulated in the osteoarthritic ACL tissues (fold change ≥2, P-value <0.05). The expression levels of 12 miRNAs were validated by quantitative PCR, and the corresponding results revealed an excellent correlation with the microarray data (R2=0.889). Genes (such as a disintegrin and metalloproteinase domain with thrombospondin type-1 motifs, bone morphogenetic protein-2, runt related transcription factor-2, collagen-1A1 and 2, interleukin-6 and transforming growth factor-β) involved in cartilage development and remodeling, collagen biosynthesis and degradation, inflammatory response and extracellular matrix homeostasis were predicted as potential targets of the dysregulated miRNAs. Moreover, a large set of putative genes were enriched in OA pathogenesis-associated pathways (such as mitogen-activated protein kinase and vascular endothelial growth factor signaling pathway). Collectively, the data from our study provides novel insight into the ligament injury-related miRNA dysregulation in patients with OA.

Decreased activity of plasma ADAMTS13 are related to enhanced cytokinemia and endotoxemia in patients with acute liver failure.

Deficient ADAM metalloproteinase with thrombospondin type-1 motif, member 13 (ADAMTS13) activity (ADAMTS13:AC) results in the accumulation of unusually large von Willebrand factor multimers (UL-VWFM) and causes microcirculatory disturbances and multiple organ failure, while endotoxins trigger the activation of a coagulation cascade. The objective of the present study was to explore the role of ADAMTS13 in endotoxemia in patients with acute liver failure (ALF). Plasma concentrations of endotoxin and cytokines, including interleukin (IL)-6 and IL-8, and activity of the plasma ADAMTS13 inhibitor were determined, along with ADAMTS13:AC, the VWF antigen (VWF:Ag) and UL-VWFM, in 27 patients with acute hepatitis (AH), 11 patients with ALF, and 10 healthy controls. IL-6 and IL-8 concentrations on admission were significantly higher in patients with ALF than in those with AH or in healthy controls. ADAMTS13:AC concomitantly decreased and VWF:Ag progressively increased with increasing cytokine concentrations from the normal range to >100 pg/ml. The inhibitor was detected in 8 patients with ALF (0.6 to 2.4 BU/ml) and 6 patients with AH (0.6 to 0.8 BU/ml). Patients with the inhibitor reported lower ADAMTS13:AC, higher VWF:Ag and lower functional liver capacity than those without the inhibitor. Collectively, the findings suggested that decreased ADAMTS13:AC and increased VWF:Ag may be induced by pro-inflammatory cytokinemia as well as the presence of the ADAMTS13 inhibitor, both of which may be closely related to enhanced endotoxemia in patients with ALF.

Glucose fluctuation and the resultant endothelial injury are correlated with pancreatic β cell dysfunction in patients with coronary artery disease.

We evaluated whether glucose fluctuation (GF) causes vascular endothelial injury and affects glucometabolic factors during lengthy oral glucose tolerance test (OGTT). We enrolled consecutive 116 patients with coronary artery disease (CAD) who were performed coronary angiography and 4-h OGTT. Blood samples were collected before and 4h after glucose load to measure endothelial injury factor [von Willebrand factor (vWF) and vWF/a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) ratio]. GF was defined as maximum - minimum blood glucose levels during 4-h OGTT. We estimated the relationship between GF and glucometabolic factors. vWV and vWF/ADAMTS-13 ratio were significantly correlated with GF during 4-h OGTT. GF was significantly correlated with homeostasis model to assess insulin resistance (HOMA-IR) (R=0.262), Matsuda index (R=-0.405), insulinogenic index (R=-0.336), HbA1c (R=0.281) and disposition index (R=-0.672). When dividing patients into impaired and preserved category groups according to the average value of GF (122mg/dL), adjusted to age, sex, HOMA-β, insulinogenic index, HOMA-IR, Matsuda index and HbA1c, disposition index was an independent risk factor for impaired GF [odds ratio (95% confidence interval): 2.87 (1.70-4.83), P<0.001]. Pancreatic β cell dysfunction is associated with GF and causes endothelial injury in CAD patients.

Crosstalk Between T Lymphocytes and Lung Fibroblasts: Generation of a Hyaluronan-Enriched Extracellular Matrix Adhesive for Monocytes.

In immunity and inflammation, T cells are often associated with stromal mesenchymal cells such as fibroblasts. Hyaluronan and proteins that associate with hyaluronan such as versican and tumor necrosis factor-inducible gene-6 (TSG-6) are extracellular matrix (ECM) components that promote leukocyte adhesion, accumulation, and activation. However, the factors responsible for producing this specialized ECM and its impact on inflammatory events are not well understood. In this study, we explored the role of T cells in stimulating lung fibroblasts to produce an ECM that impacts monocyte adhesion. We found that CD3/CD28-activated human CD4+ T cells when co-cultured with human lung fibroblasts stimulated the expression of mRNA for hyaluronan synthase 2 (HAS2) and decreased the expression of hyaluronidase 2 (HYAL2). This led to an increase in the deposition of hyaluronan that formed cable-like structures within the ECM. Co-culturing activated T cells with fibroblasts also led to increased expression and accumulation of TSG-6. Surprisingly, addition of activated CD4+ T cells to the fibroblasts reduced the expression of mRNA for versican, and increased the expression of enzymes that degrade versican, such as ADAMTS4 and ADAMTS9 (a disintegrin and metalloproteinase with a thrombospondin type-1 motif) leading to a decrease in versican in the ECM of the co-cultures. Furthermore, addition of human monocytes to these co-cultures resulted in elevated monocyte adhesion to the cable-like structures in the ECM when compared to controls. These results illustrate the importance of crosstalk between T cells and fibroblasts in promoting the generation of a matrix that is adhesive for monocytes. J. Cell. Biochem. 118: 2118-2130, 2017. © 2016 Wiley Periodicals, Inc.

Levels and activities of von Willebrand factor and metalloproteinase with thrombospondin type-1 motif, number 13 in inflammatory bowel diseases.

AIMTo evaluate the levels of von Willebrand factor (VWF) and metalloproteinase with thrombospondin type-1 motif, number 13 (ADAMTS13) in inflammatory bowel disease (IBD) and correlate them with the disease activity.METHODSConsecutive patients with IBD aged 18 years or older were enrolled in the study. Forty-seven patients with ulcerative colitis (UC), 38 with Crohn’s disease (CD), and 50 healthy controls were included. The white blood cell count, haematocrit, platelet count, fibrinogen, partial activated thromboplastin time, C-reactive protein, albumin, VWF antigen level (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), VWF collagen-binding activity (VWF:CB), and ADAMTS13 antigen level (ADAMTS13:Ag) and activity (ADAMTS13act) were measured. The following ratios were assessed: VWF:RCo/VWF:Ag, VWF:CB/VWF:Ag, VWF:Ag/ADAMTS13act, and ADAMTS13act/ADAMTS13:Ag.RESULTSCompared to controls, the odds ratio (OR) of an elevated VWF: Ag > 150% was 8.7 (95%CI: 2.7-28.1) in the UC group and 16.2 (95%CI: 4.8-54.0) in the CD group. VWF:CB was lower in UC patients, and active CD was associated with a higher VWF: RCo (+38%). The ORs of VWF:CB/VWF:Ag < 0.7 (a marker of acquired von Willebrand syndrome) in the UC and CD groups were 11.9 (95%CI: 4.4-32.4) and 13.3 (95%CI: 4.6-38.1), respectively. Active UC was associated with lower ADAMTS13:Ag (-23%) and ADAMTS13act (-20%) compared to UC in remission. Patients with active CD had a 15% lower ADAMTS13act than controls. The activity of UC, but not that of CD, was inversely correlated with ADAMTS13:Ag (r = -0.76) and ADAMTS13act (r = -0.81).CONCLUSIONComplex VWF-ADAMTS13-mediated mechanisms disturb haemostasis in IBD. A reduced WVF:CB is a risk factor for bleeding, while a lower ADAMTS13 level combined with an elevated VWF:Ag could predispose one to thrombosis.

The ADAMTS hyalectanase family: biological insights from diverse species.

The a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs (ADAMTS) family of metzincins are complex secreted proteins that have diverse functions during development. The hyalectanases (ADAMTS1, 4, 5, 8, 9, 15 and 20) are a subset of this family that have enzymatic activity against hyalectan proteoglycans, the processing of which has important implications during development. This review explores the evolution, expression and developmental functions of the ADAMTS family, focusing on the ADAMTS hyalectanases and their substrates in diverse species. This review gives an overview of how the family and their substrates evolved from non-vertebrates to mammals, the expression of the hyalectanases and substrates in different species and their functions during development, and how these functions are conserved across species.

Association of the von Willebrand Factor-ADAMTS13 Ratio With Incident Cardiovascular Events in Patients With Peripheral Arterial Disease.

Platelet adhesion is mediated by von Willebrand factor (vWF), and disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13 (ADAMTS13) is a protease that cleaves vWF. A change in the balance between vWF and ADAMTS13 in favor of thrombosis might occur shortly before ischemic cardiovascular (CV) events. To determine whether vWF, ADAMTS13, and the ratio of vWF and ADAMTS13 change during the months preceding an acute CV event. Prospective longitudinal observational study. Outpatient. A total of 595 participants with peripheral artery disease (PAD). Blood samples were obtained every 2 months for up to 3 years and hemostatic factors examined at intervals preceding events. Sixty-one participants (cases) experienced events and were matched to 122 PAD controls. During the 2-month interval prior to an event, cases (n = 48) had higher levels of the vWF and ADAMTS13 than controls (n = 95; P = .05), but significance was lost after adjusting for the baseline differences in myocardial infarction, unstable angina, and stroke. During the 10 months prior to an event, median values for vWF and the ratio of vWF and ADAMTS13 were higher in cases than in controls, but the differences were not statistically significant. However, in a subset of 20 patients with complete bimonthly data, there was a trend toward an increase in the ratio in the 10 months prior to a CV event ( P = .04). In patients with PAD experiencing an ischemic CV event, a significant increase in the ratio of vWF to ADAMTS13 prior to the event could not be confirmed, although there was a weak trend in this direction.

Genetic and biochemical evidence that gastrulation defects in Pofut2 mutants result from defects in ADAMTS9 secretion

Protein O-fucosyltransferase 2 (POFUT2) adds O-linked fucose to Thrombospondin Type 1 Repeats (TSR) in 49 potential target proteins. Nearly half the POFUT2 targets belong to the A Disintegrin and Metalloprotease with ThromboSpondin type-1 motifs (ADAMTS) or ADAMTS-like family of proteins. Both the mouse Pofut2 RST434 gene trap allele and the Adamts9 knockout were reported to result in early embryonic lethality, suggesting that defects in Pofut2 mutant embryos could result from loss of O-fucosylation on ADAMTS9. To address this question, we compared the Pofut2 and Adamts9 knockout phenotypes and used Cre-mediated deletion of Pofut2 and Adamts9 to dissect the tissue-specific role of O-fucosylated ADAMTS9 during gastrulation. Disruption of Pofut2 using the knockout (LoxP) or gene trap (RST434) allele, as well as deletion of Adamts9, resulted in disorganized epithelia (epiblast, extraembryonic ectoderm, and visceral endoderm) and blocked mesoderm formation during gastrulation. The similarity between Pofut2 and Adamts9 mutants suggested that disruption of ADAMTS9 function could be responsible for the gastrulation defects observed in Pofut2 mutants. Consistent with this prediction, CRISPR/Cas9 knockout of POFUT2 in HEK293T cells blocked secretion of ADAMTS9. We determined that Adamts9 was dynamically expressed during mouse gastrulation by trophoblast giant cells, parietal endoderm, the most proximal visceral endoderm adjacent to the ectoplacental cone, extraembryonic mesoderm, and anterior primitive streak. Conditional deletion of either Pofut2 or Adamts9 in the epiblast rescues the gastrulation defects, and identified a new role for O-fucosylated ADAMTS9 during morphogenesis of the amnion and axial mesendoderm. Combined, these results suggested that loss of ADAMTS9 function in the extra embryonic tissue is responsible for gastrulation defects in the Pofut2 knockout. We hypothesize that loss of ADAMTS9 function in the most proximal visceral endoderm leads to slippage of the visceral endoderm and altered characteristics of the extraembryonic ectoderm. Consequently, loss of input from the extraembryonic ectoderm and/or compression of the epiblast by Reichert's membrane blocks gastrulation. In the future, the Pofut2 and Adamts9 knockouts will be valuable tools for understanding how local changes in the properties of the extracellular matrix influence the organization of tissues during mammalian development.

Erratum to: Prolonged thrombocytopenia after living donor liver transplantation is a strong prognostic predictor irrespective of history of splenectomy: the significance of ADAMTS13 and graft function.

The precise mechanism of prolonged thrombocytopenia following living donor liver transplantation (LDLT) remains unclear. To determine risk factors associated with prolonged thrombocytopenia following LDLT, with a focus on the activity of ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs member 13) and the influence of splenectomy. Adult LDLT patients were divided into two groups on the basis of platelet counts (100 × 103/μL) on POD 14: high and low platelet (HP and LP) groups. Survival analysis was performed in the 100 patients, and ADAMTS13 activity and von Willebrand factor (VWF) levels in the plasma were measured in 65 adult recipients. The 6-month survival rate was significantly lower in the LP group (n = 36) than in the HP group (n = 62) (61.1 vs. 93.5 %). ADAMTS13 activity had been significantly lower in the LP group (n = 23) than in the HP group (n = 42). The VWF/ADAMTS13 ratio was significantly higher in the LP group than in the HP group. The independent risk factors for thrombocytopenia on POD14 were preoperative AT levels and ADAMTS13 activity on POD14. TPO levels on POD14 were significantly higher in the LP group than in the HP group, while those on POD28 in the LP group were significantly decreased, despite the low platelet levels. Irrespective of splenectomy history, platelet counts and ADAMTS13 activity in the LP group remained low until POD28, while VWF/ADAMTS13 ratio significantly increased until POD28. These results suggest that prolonged thrombocytopenia after LDLT was associated with not only a decrease in ADAMTS13 due to sinusoidal endothelial cell injury, but also low TPO production due to hepatocyte dysfunction, irrespective of history of splenectomy.

Hemostatic Markers and Long-Term Risk of Intracerebral Hemorrhage in Postmenopausal Women

Known risk factors for intracerebral hemorrhage (ICH) include age, hypertension, smoking, alcohol intake, and anticoagulant use. Some previous reports have indicated that hemostatic factors measured many years before the onset of ICH might predict the later occurrence of ICH. The objective of this analysis was to test whether selected hemostatic factors measured years before the onset of ICH could identify patients at higher risk for future ICH. We performed a nested case-control study within the Women's Health Initiative (WHI) cohort. Postmenopausal women aged 50-79 years (mean 68) at baseline (1993-1998) were enrolled at 40 Clinical Centers in the United States and followed for adjudicated ICH for a mean of 11.4 years. ICH cases (N = 75) and controls (N = 75) were matched on age, ethnicity, blood pressure, anticoagulant use, and treated hypertension. Stored blood samples from the baseline WHI examination were tested for von Willebrand factor (vWF), a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13 (ADAMTS13), tissue plasminogen activator (t-PA), and urokinase plasminogen activator (u-PA). Platelet count, white blood cell count, and hemoglobin concentration were also measured. Mean baseline levels of vWF (1.03 and .95 U/mL), ADAMTS13 (1.0 and 1.1 µg/mL), vWF:ADAMTS13 ratio (.99 and .92), t-PA (14.75 and 14.80 IU/mL), and u-PA (.09 and .10 IU/mL) were not significantly different by case-control status. Significant differences were also not identified for platelet count, hemoglobin, white blood count, or reported alcohol use. None of the 4 baseline hemostatic factors nor the platelet count was predictive of future ICH risk in this long-term study of older postmenopausal women.

Effects of baicalin on collagen Ι and collagen ΙΙΙ expression in pulmonary arteries of rats with hypoxic pulmonary hypertension.

The synthesis and accumulation of collagen play an important role in the formation and progression of hypoxic pulmonary hypertension. Baicalin has been reported to prevent bleomycin-induced pulmonary fibrosis. However, the role of baicalin in the treatment of pulmonary hypertension remains unknown. A disintegrin and metalloprotease with thrombospondin type-1 motif (ADAMTS-1) is a secreted enzyme that acts on a wide variety of extracellular matrix (ECM) substrates associated with vascular diseases. In this study, we aimed to investigate the effects of baicalin on the synthesis of collagen I in rats with pulmonary hypertension induced by hypoxia and the changes in ADAMTS-1 expression. A total of 24 Sprague Dawley rats were randomly assigned to 3 groups as follows: the control group (C), the hypoxia group (H) and the hypoxia + baicalin group (B). The rats in groups H and B were kept in a normobaric hypoxic chamber for 4 weeks, and the rats in group C were exposed to room air. We measured the hemodynamic indexes, including mean pulmonary artery pressure (mPAP), mean systemic (carotid) artery pressure (mSAP), and then calculated the mass ratio of right ventricle to left ventricle plus septum [RV/(LV + S)] to reflect the extent of right ventricular hypertrophy. We measured the mRNA and protein expression levels of type I collagen, type III collagen and ADAMTS-1 by hybridization in situ, and immunohistochemistry and western blot analysis, respectively. The results revealed that treatment with baicalin significantly reduced pulmonary artery pressure and attenuated the remodeling of the pulmonary artery under hypoxic conditions by increasing the expression of ADAMTS-1, so that the synthesis of type I collagen and its mRNA expression were inhibited. In conclusion, baicalin effectively inhibits the synthesis of collagen I in pulmonary arteries and this is associated with an increase in the expression of ADAMTS-1. Thus, treatment with baicalin may be an effective method for lowering pulmonary artery pressure and preventing pulmonary artery remodeling.

Hyaluronan suppresses mechanical stress-induced expression of catabolic enzymes by human chondrocytes via inhibition of IL-1β production and subsequent NF-κB activation.

To investigate the inhibitory effect of hyaluronan (HA) on mechanical stress- induced expression of a disintegrin and metalloproteinase with thrombospondin type 1 motifs (ADAMTS)-4, -5 and matrix metalloproteinase (MMP)-13 by human chondrocytes. Normal human articular chondrocytes were pre-incubated with or without 1.0 mg/mL HA (2700 kDa) for 12 h at 37 °C in stretch chambers, then they were exposed to uni-axial cyclic tensile strain (CTS, 0.5 Hz, 10% elongation). The expression of ADAMTS-4, -5, and MMP-13 were analyzed by real-time polymerase chain reaction and Immunocytochemistry. The concentration of IL-1β in the supernatant was measured using enzyme-linked immunosorbent assay (ELISA). The nuclear translocation of runt-related transcription factor 2 (RUNX-2) and nuclear factor-κB (NF-κB) was examined by ELISA and immunocytochemistry, and phosphorylation of NF-κB was examined by western blotting. HA inhibited mRNA expression of ADAMTS-4, -5, and MMP13 after 24 h CTS via inhibition of IL-1β secretion and NF-κB activation. However, HA failed to inhibit CTS-induced RUNX-2 expression and subsequent expression of ADAMTS-5 and MMP-13 1 h after CTS. Our results demonstrated that HA significantly suppressed mechanical stress-induced expression of catabolic proteases by inhibition of the NF-κB-IL-1β pathway, but did not suppress mechanical stress-induced RUNX-2 signaling.

The novel ADAMTS13‐p.D187H mutation impairs ADAMTS13 activity and secretion and contributes to thrombotic thrombocytopenic purpura in mice

Congenital thrombotic thrombocytopenic purpura (TTP) is characterized by mutations in the ADAMTS13 gene, which either impair protein secretion or influence ADAMTS13 (A Disintegrin-like And Metalloprotease domain with ThromboSpondin type-1 motif, member 13) activity. Phenotypic consequences of these mutations have not yet been evaluated in animal models for TTP. To identify the in vitro effect of a novel ADAMTS13 mutation and to investigate whether this mutation induces TTP in vivo. All 29 ADAMTS13 exons with exon-intron boundaries of a patient with pregnancy-onset TTP were sequenced. Wild-type and mutant ADAMTS13 proteins were both transiently and stably expressed in human embryonic kidney cells, and their activity was evaluated in vitro using fluorescence resonance energy transfer and flow assays. Molecular dynamics simulations were performed to study Ca(2+) stability. Adamts13(-/-) mice were hydrodynamically injected with wild-type and mutant expression plasmids and triggered with recombinant human von Willebrand factor. We identified a novel heterozygous c.559G>C mutation in exon 6 of the proposita's ADAMTS13 gene. This mutation resulted in a p.Asp187His substitution (p.D187H), which was located in the high affinity Ca(2+) -binding site in the metalloprotease domain of ADAMTS13. The homozygous p.D187H mutation down-regulated ADAMTS13 activity in vitro. Impaired proteolytic activity was linked to unstable Ca(2+) binding as visualized using a molecular dynamics simulation. In addition, the p.D187H mutation affects protein secretion in vitro. In Adamts13(-/-) mice, the homozygous p.D187H mutation reduced ADAMTS13 secretion and activity and contributed to TTP when these mice were triggered with recombinant human von Willebrand factor. Our data indicate that the p.D187H mutation impairs ADAMTS13 activity and secretion and is responsible for TTP onset in mice.

Relevance of ADAMTS13 to liver transplantation and surgery.

A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) specifically cleaves unusually-large von Willebrand factor (VWF) multimers under high shear stress, and down-regulates VWF function to form platelet thrombi. Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease, termed thrombotic microangiopathy (TMA) including thrombotic thrombocytopenic purpura (TTP). Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA, with a concomitant decrease of plasma ADAMTS13 activity. Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13. In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells. Subsequently, it was found that ADADTS13 was not merely responsible to development of TMA and TTP, but also related to some kinds of liver dysfunction after liver transplantation. Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP. The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors. Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance. It can be called as "local TTP like mechanism" which plays a crucial role in liver dysfunction after liver transplantation and surgery.

A new biological marker candidate in female reproductive system diseases: Matrix metalloproteinase with thrombospondin motifs (ADAMTS).

Playing a key role in the pathophysiology of many diseases, A Disintegrin-like and Metalloproteinase with Thrombospondin type-1 motif (ADAMTS) proteinases have been attracted more attention in obstetrics and gynecology. First discovered in 1997, this zinc-dependent proteinase family has 19 members today. These enzymes, which are located in the extracellular matrix (ECM), have a lot of very important functions, like matrix formation and resorption, angiogenesis, ovulation, and coagulation. In addition, in the pathogenesis of cancer, inflammation, arthritis, and connective tissue diseases, ADAMTS proteinases have crucial roles. The purpose of this review is to collect previous studies about obstetrics and gynecology that are related to ADAMTS enzymes and discuss the subject in many aspects to give an idea to the investigators who are interested in the subject.

Prolonged thrombocytopenia after living donor liver transplantation is a strong prognostic predictor irrespective of history of splenectomy: the significance of ADAMTS13 and graft function

The precise mechanism of prolonged thrombocytopenia following living donor liver transplantation (LDLT) remains unclear. To determine risk factors associated with prolonged thrombocytopenia following LDLT, with a focus on the activity of ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs member 13) and the influence of splenectomy. Adult LDLT patients were divided into two groups on the basis of platelet counts (100 × 10(3)/μL) on POD 14: high and low platelet (HP and LP) groups. Survival analysis was performed in the 100 patients, and ADAMTS13 activity and von Willebrand factor (VWF) levels in the plasma were measured in 65 adult recipients. The 6-month survival rate was significantly lower in the LP group (n = 36) than in the HP group (n = 62) (61.1 vs. 93.5 %). ADAMTS13 activity had been significantly lower in the LP group (n = 23) than in the HP group (n = 42). The VWF/ADAMTS13 ratio was significantly higher in the LP group than in the HP group. The independent risk factors for thrombocytopenia on POD14 were preoperative AT levels and ADAMTS13 activity on POD14. TPO levels on POD14 were significantly higher in the LP group than in the HP group, while those on POD28 in the LP group were significantly decreased, despite the low platelet levels. Irrespective of splenectomy, platelet counts and ADAMTS13 activity in the LP group remained low until POD28, while VWF/ADAMTS13 ratio significantly increased until POD28. These results suggest that prolonged thrombocytopenia after LDLT was associated with not only a decrease in ADAMTS13 due to sinusoidal endothelial cell injury, but also low TPO production due to hepatocyte dysfunction, irrespective of splenectomy [corrected].

AB0072 Hyaluronan inhibition of mechanical stress-induced protease expressions by human chondrocytes

BackgroundRecent studies have demonstrated that hyaluronan (HA) suppresses inflammatory cytokine-induced catabolic proteases such as member of a disintegrin and metalloproteinase with thrombospondin type1 motifs (ADAMTS), or matrix metalloproteinases (MMPs)1). However...

C-Maf Transcription Factor Regulates ADAMTS-12 Expression in Human Chondrogenic Cells.

Objective:ADAMTS (a disintegrin and metalloproteinase with thrombospondin type-1 motif) zinc metalloproteinases are important during the synthesis and breakdown of cartilage extracellular matrix. ADAMTS-12 is up-regulated during in vitro chondrogenesis and embryonic limb development; however, the regulation of ADAMTS-12 expression in cartilage remains unknown. The transcription factor c-Maf is a member of Maf family of basic ZIP (bZIP) transcription factors. Expression of c-Maf is highest in hypertrophic chondrocytes during embryonic development and postnatal growth. We hypothesize that c-Maf and ADAMTS-12 are co-expressed during chondrocyte differentiation and that c-Maf regulates ADAMTS-12 expression during chondrogenesis.Design:Promoter analysis and species alignments identified potential c-Maf binding sites in the ADAMTS-12 promoter. c-Maf and ADAMTS-12 co-expression was monitored during chondrogenesis of stem cell pellet cultures. Luciferase expression driven by ADAMTS-12 promoter segments was measured in the presence and absence of c-Maf, and synthetic oligonucleotides were used to confirm specific binding of c-Maf to ADAMTS-12 promoter sequences.Results:In vitro chondrogenesis from human mesenchymal stem cells revealed co-expression of ADAMTS-12 and c-Maf during differentiation. Truncation and point mutations of the ADAMTS-12 promoter evaluated in reporter assays localized the response to the proximal 315 bp of the ADAMTS-12 promoter, which contained a predicted c-Maf recognition element (MARE) at position -61. Electorphoretic mobility shift assay confirmed that c-Maf directly interacted with the MARE at position -61.Conclusions:These data suggest that c-Maf is involved in chondrocyte differentiation and hypertrophy, at least in part, through the regulation of ADAMTS-12 expression at a newly identified MARE in its proximal promoter.

New Wrinkle Between Cancer and Blood Coagulation: Metastasis and Cleavage of von Willebrand Factor by ADAM28

New Wrinkle Between Cancer and Blood Coagulation: Metastasis and Cleavage of von Willebrand Factor by ADAM28

ADAMTS13 gene deletion enhances plasma high-mobility group box1 elevation and neuroinflammation in brain ischemia–reperfusion injury

Highly adhesive glycoprotein von Willebrand factor (VWF) multimer induces platelet aggregation and leukocyte tethering or extravasation on the injured vascular wall, contributing to microvascular plugging and inflammation in brain ischemia-reperfusion. A disintegrin and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) cleaves the VWF multimer strand and reduces its prothrombotic and proinflammatory functions. Although ADAMTS13 deficiency is known to amplify post-ischemic cerebral hypoperfusion, there is no report available on the effect of ADAMTS13 on inflammation after brain ischemia. We investigated if ADAMTS13 deficiency intensifies the increase of extracellular HMGB1, a hallmark of post-stroke inflammation, and exacerbates brain injury after ischemia-reperfusion. ADAMTS13 gene knockout (KO) and wild-type (WT) mice were subjected to 30-min middle cerebral artery occlusion (MCAO) and 23.5-h reperfusion under continuous monitoring of regional cerebral blood flow (rCBF). The infarct volume, plasma high-mobility group box1 (HMGB1) level, and immunoreactivity of the ischemic cerebral cortical tissue (double immunofluorescent labeling) against HMGB1/NeuN (neuron-specific nuclear protein) or HMGB1/MPO (myeloperoxidase) were estimated 24 h after MCAO. ADAMTS13KO mice had larger brain infarcts compared with WT 24 h after MCAO (p < 0.05). The rCBF during reperfusion decreased more in ADAMTS13KO mice. The plasma HMGB1 increased more in ADAMTS13KO mice than in WT after ischemia-reperfusion (p < 0.05). Brain ischemia induced more prominent activation of inflammatory cells co-expressing HMGB1 and MPO and more marked neuronal death in the cortical ischemic penumbra of ADAMTS13KO mice. ADAMTS13 deficiency may enhance systemic and brain inflammation associated with HMGB1 neurotoxicity, and aggravate brain damage in mice after brief focal ischemia. We hypothesize that ADAMTS13 protects brain from ischemia-reperfusion injury by regulating VWF-dependent inflammation as well as microvascular plugging.