The effect of ADAMTS13 on graft-versus-host disease.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) can potentially cure malignant blood disorders and benign conditions such as haemoglobinopathies and immunologic diseases. However, allo-HSCT is associated with significant complications. The most common and debilitating among them is graft-versus-host disease (GVHD). In GVHD, donor-derived T cells mount an alloimmune response against the recipient. The alloimmune response involves several steps, including recognition of recipient antigens, activation and proliferation of T cells in secondary lymphoid organs, and homing into GVHD-targeted organs. Adhesion molecules on T cells and endothelial cells mediate homing of T cells into lymphoid and non-lymphoid tissues. In this study, we showed that Von Willebrand factor (VWF), an adhesion molecule secreted by activated endothelial cells, plays an important role in mouse models of GVHD. We investigated the effect of the VWF-cleaving protease ADAMTS13 on GVHD. We found that ADAMTS13 reduced the severity of GVHD after bone marrow transplantation from C57BL6 donor to BALB/C recipient mice. A recombinant VWF-A2 domain peptide also reduced GVHD in mice. We showed that ADAMTS13 and recombinant VWF-A2 reduced the binding of T cells to endothelial cells and VWF in vitro, and reduced the number of T cells in lymph nodes, Peyer's patches and GVHD-targeted organs in vivo. We identified LFA-1 (αLß2) as the binding site of VWF on T cells. Our results showed that blocking T-cell homing by ADAMTS13 or VWF-A2 peptide reduced the severity of the GVHD after allo-HSCT, a potentially novel method for treating and preventing GVHD.

Novel mechanisms of action of emerging therapies of hereditary thrombotic thrombocytopenic purpura.

INTRODUCTION: Hereditary thrombotic thrombocytopenic purpura (hTTP) is caused by deficiency of plasma ADAMTS13 activity, resulting from ADAMTS13 mutations. ADAMTS13 cleaves ultra large von Willebrand factor (VWF), thus reducing its multimer sizes. Hereditary deficiency of plasma ADAMTS13 activity leads to the formation of excessive platelet-VWF aggregates in small arterioles and capillaries, resulting in hTTP. AREAS COVERED: PubMed search from 1956 to 2024 using thrombotic thrombocytopenic purpura and therapy identified 3,675 articles. Only the articles relevant to the topic were selected for discussion, which focuses on pathophysiology, clinical presentations, and mechanisms of action of emerging therapeutics for hTTP. Current therapies include infusion of plasma, or coagulation factor VIII, or recombinant ADAMTS13. Emerging therapies include anti-VWF A1 aptamers or nanobody and gene therapies with adeno-associated viral vector or self-inactivated lentiviral vector or a sleeping beauty transposon system for a long-term expression of a functional ADAMTS13 enzyme. EXPERT OPINION: Frequent plasma infusion remains to be the standard of care in most parts of the world, while recombinant ADAMTS13 has become the treatment of choice for hTTP in some of the Western countries. The success of gene therapies in preclinical models may hold a promise for future development of these novel approaches for a cure of hTTP.

Cathepsin K deficiency prevented stress-related thrombosis in a mouse FeCl3 model.

BACKGROUND: Exposure to chronic psychological stress (CPS) is a risk factor for thrombotic cardiocerebrovascular diseases (CCVDs). The expression and activity of the cysteine cathepsin K (CTSK) are upregulated in stressed cardiovascular tissues, and we investigated whether CTSK is involved in chronic stress-related thrombosis, focusing on stress serum-induced endothelial apoptosis. METHODS AND RESULTS: Eight-week-old wild-type male mice (CTSK+/+) randomly divided to non-stress and 3-week restraint stress groups received a left carotid artery iron chloride3 (FeCl3)-induced thrombosis injury for biological and morphological evaluations at specific timepoints. On day 21 post-stress/injury, the stress had enhanced the arterial thrombi weights and lengths, in addition to harmful alterations of plasma ADAMTS13, von Willebrand factor, and plasminogen activation inhibitor-1, plus injured-artery endothelial loss and CTSK protein/mRNA expression. The stressed CTSK+/+ mice had increased levels of injured arterial cleaved Notch1, Hes1, cleaved caspase8, matrix metalloproteinase-9/-2, angiotensin type 1 receptor, galactin3, p16IN4A, p22phox, gp91phox, intracellular adhesion molecule-1, TNF-α, MCP-1, and TLR-4 proteins and/or genes. Pharmacological and genetic inhibitions of CTSK ameliorated the stress-induced thrombus formation and the observed molecular and morphological changes. In cultured HUVECs, CTSK overexpression and silencing respectively increased and mitigated stressed-serum- and H2O2-induced apoptosis associated with apoptosis-related protein changes. Recombinant human CTSK degraded γ-secretase substrate in a dose-dependent manor and activated Notch1 and Hes1 expression upregulation. CONCLUSIONS: CTSK appeared to contribute to stress-related thrombosis in mice subjected to FeCl3 stress, possibly via the modulation of vascular inflammation, oxidative production and apoptosis, suggesting that CTSK could be an effective therapeutic target for CPS-related thrombotic events in patients with CCVDs.

Removal of endothelial surface-associated von villebrand factor suppresses accelerate datherosclerosis after myocardial infarction.

BACKGROUND: Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI). METHODS: Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21. RESULTS: Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p < 0.01) in post-MI mice versus sham-treated animals at day 3 and 21. Treatment with NAC and ADAMTS13 significantly attenuated the post-MI increase for all four molecular targets by > 50% (p < 0.05 vs. non-treated at day 3 and 21). On aortic root histology, mice undergoing MI versus controls had 2-4 fold greater plaque size and macrophage content (p < 0.05), approximately 20-fold greater platelet adhesion (p < 0.05), and increased staining for markers of platelet transforming growth factor-ß1 signaling. Accelerated plaque growth and inflammatory activation was almost entirely prevented by ADAMTS13 and NAC. Inhibition of FXI had no significant effect on molecular imaging signal or plaque morphology. CONCLUSIONS: Plaque inflammatory activation in remote arteries after MI is strongly influenced by VWF-mediated platelet adhesion to the endothelium. These findings support investigation into new secondary preventive therapies for reducing non-culprit artery events after MI.

Reduction of mortality, cardiac damage, and cerebral damage by IL-1 inhibition in a murine model of TTP.

ABSTRACT: Thrombotic thrombocytopenic purpura (TTP), a rare but fatal disease if untreated, is due to alteration in von Willebrand factor cleavage resulting in capillary microthrombus formation and ischemic organ damage. Interleukin-1 (IL-1) has been shown to drive sterile inflammation after ischemia and could play an essential contribution to postischemic organ damage in TTP. Our objectives were to evaluate IL-1 involvement during TTP and to test the efficacy of the recombinant IL-1 receptor antagonist, anakinra, in a murine TTP model. We retrospectively measured plasma IL-1 concentrations in patients with TTP and controls. Patients with TTP exhibited elevated plasma IL-1α and -1ß concentrations, which correlated with disease course and survival. In a mouse model of TTP, we administered anakinra (IL-1 inhibitor) or placebo for 5 days and evaluated the efficacy of this treatment. Anakinra significantly reduced mortality of mice (P < .001). Anakinra significantly decreased TTP-induced cardiac damage as assessed by blood troponin concentrations, evaluation of left ventricular function by echocardiography, [18F]fluorodeoxyglucose positron emission tomography of myocardial glucose metabolism, and cardiac histology. Anakinra also significantly reduced brain TTP-induced damage evaluated through blood PS100b concentrations, nuclear imaging, and histology. We finally showed that IL-1α and -1ß trigger endothelial degranulation in vitro, leading to the release of von Willebrand factor. In conclusion, anakinra significantly reduced TTP mortality in a preclinical model of the disease by inhibiting both endothelial degranulation and postischemic inflammation, supporting further evaluations in humans.

[ADAMTS13-Mediated Proteolytic Cleavage of Unusually Large von Willebrand Factor Polymers on Endothelial Cells in the Absence of Fluid Shear Stress].

OBJECTIVE: To investigate the molecular mechanism of proteolytic cleavage of unusually large von Willebrand Factor(ULVWF) on endothelial cells by ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats-13) in the absence of fluid shear stress, so as to provide a theoretical basis for the pathogenesis of thrombotic thrombocytopenic purpura (TTP) and other thrombotic disorders. METHODS: The ADAMTS13-mediated proteolysis of ULVWF on the surface of endothelial cells in the absence of fluid shear stress was observed through immunofluorescence microscopy. The variation in VWF antigen levels in the conditioned media were determined by ELISA assay. The levels of VWF and the proteolytic fragments released into the conditioned media were determined by ELISA assay and Western blot in the absence and presence of fluid shear stress or FVIII. The effect of ADAMTS13-mediated ULVWF cleavage on the normal distribution of plasma VWF multimers was evaluated by multimer analysis. Histamine stimulated human umbilical vein endothelial cells (HUVECs) were incubated with ADAMTS13 and various N- and C-terminally truncated mutants. Then the ULVWF that maintained binding to the cells were observed through immunofluorescence microscopy and the soluble ULVWF released from endothelial cells was determined by ELISA, so as to demonstrate the domains of ADAMTS13 required for proteolysis of ULVWF on endothelial cells. RESULTS: The ULVWF strings on the endothelial cell surface were rapidly proteolyzed by recombinant and plasma ADAMTS13 in the absence of fluid shear stress. This proteolytic processing of ULVWF depended on incubation time and ADAMTS13 concentration, but not shear stress and FVIII. The distribution of VWF releaseded by ADAMTS13-mediated proteolysis was quite similar to that secreted by endothelial cells under histamine stimulation, suggesting the ULVWF cleavage occured at the cell surface. The proteolysis of the ULVWF on endothelial cells required the Cys-rich(CysR) and spacer domains, but not the TSP1 2-8 and CUB domains of ADAMTS13. CONCLUSION: The ULVWF polymers on endothelial cells are sensitive to ADAMTS13-mediated cleavage even in the absence of fluid shear stress. The findings provide novel insight into the molecular mechanism of ADAMTS13-mediated ULVWF cleavage at the cellular level and may contribute to understanding of the pathogenesis of TTP and other thrombotic disorders.

Peak ADAMTS13 activity to assess ADAMTS13 conformation and risk of relapse in immune-mediated thrombotic thrombocytopenic purpura.

ABSTRACT: Previous studies have demonstrated that >38% of patients with immune-mediated thrombotic thrombocytopenic purpura in remission with activity >50% had an open ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) conformation. We assessed ADAMTS13 conformation in remission (ADAMTS13 activity >60%), focusing on peak ADAMTS13 activity levels and longitudinal assessment in 420 samples across 157 patients. Fewer cases had an open conformation at peak ADAMTS13 activity than unselected remission samples with ADAMTS13 activity >60% (23% vs 43%). Patients with a closed ADAMTS13 conformation at peak ADAMTS13 activity had an eightfold lower relapse rate in the subsequent year (9% vs 46%) and a fivefold lower relapse rate within 2 years (23% vs 62%) compared with cases with an open conformation. Patients with an open conformation at peak ADAMTS13 activity required preemptive anti-CD20 treatment earlier than those with a closed conformation (median, 10 vs 25 months). Longitudinally, an open conformation was evident at, and often preceded relapse. When the conformation was already open before relapse, an increase in the conformation index at relapse was seen despite the undetectable anti-ADAMTS13 immunoglobulin G (IgG) antibody. In cases with detectable anti-ADAMTS13 IgG antibody, these became undetectable before achieving a closed conformation, highlighting the relapse risk even with undetectable anti-ADAMTS13 IgG antibody and the clinical utility of open/closed during monitoring. To our knowledge, this is the first study to show an association between relapse risk and ADAMTS13 conformation when activity levels are at a peak. The open conformation identifies antibody-mediated subclinical disease that is not detectable by the current ADAMTS13 testing.

Targeting neutrophil extracellular trap accumulation under flow in patients with immune-mediated thrombotic thrombocytopenic purpura.

ABSTRACT: Neutrophil NETosis is a unique form of cell death, characterized by the release of decondensed chromatin and antimicrobial contents to the extracellular space, which is involved in inflammation and thrombosis. However, the role of NETosis in the pathogenesis of immune-mediated thrombotic thrombocytopenic purpura (iTTP) and how a targeted therapy affects the accumulation of neutrophil extracellular traps (NETs) under flow remain unknown. Flow cytometry demonstrated that the percentage of neutrophils undergoing NETosis in whole blood from patients with iTTP on admission was significantly increased, with a concurrent decrease in the capacity of inducible NETosis by shigatoxin. After therapy, the percentage of H3Cit+MPO+ neutrophils was significantly reduced, with an improvement in inducible NETosis in these patients. Additionally, little to no NET and thrombus formation was detected underflow in the whole blood from patients with iTTP when platelet counts were very low, but the NET and thrombus formation was dramatically increased following therapy when platelet counts rose to ≥50 × 109/L or were restored to normal with donor platelets. Similarly, there was no thrombus or NET accumulation under flow in the whole blood from vwf-/- mice, but NET accumulation was significantly higher in Adamts13-/- mice than in wild-type mice. Finally, recombinant ADAMTS13 or caplacizumab (or anfibatide) prevented NET and thrombus formation under flow in whole blood from patients with iTTP or from Adamts13-/- mice. These results indicate that neutrophil NETosis and NET formation depend on platelets and von Willebrand factor (VWF) in iTTP, and a targeted therapy such as recombinant ADAMTS13 or caplacizumab may prevent NET and thrombus formation under flow in iTTP.

Apadamtase Alfa: First Approval.

Apadamtase alfa (ADAMTS13, recombinant-krhn; ADZYNMA), a human recombinant form of a disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13), is being developed by Takeda under license from KM biologics for thrombotic thrombocytopenic purpura (TTP) and sickle cell disease. On 9 November 2023, apadamtase alfa was approved in the USA for prophylactic and on-demand enzyme replacement therapy (ERT) in paediatric and adult patients with congenital TTP. Apadamtase alfa is under regulatory review for congenital TTP in the EU and Japan, and is under clinical development for immune-mediated TTP in several countries worldwide. Clinical development of apadamtase alfa for vaso-occlusive crisis related to sickle cell anaemia is underway in the USA. This article summarizes the milestones in the development of apadamtase alfa leading to this first approval in the USA for congenital TTP.

Persistent ADAMTS13 inhibitor delays recovery of ADAMTS13 activity in caplacizumab-treated Japanese patients with iTTP.

ABSTRACT: For patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP), caplacizumab, a nanobody against von Willebrand factor A1 domain, has become crucial. Delayed normalization of ADAMTS13 activity during caplacizumab therapy has been identified. In a retrospective analysis, we compared platelet count, ADAMTS13 activity, its inhibitor, and anti-ADAMTS13 immunoglobulin G (IgG) levels in acute iTTP cases treated with caplacizumab (n = 14) or without it (n = 16). The median time from initial therapeutic plasma exchange (TPE) to the first rituximab administration was 12 days in the caplacizumab group (n = 11) and 10 days in the group without caplacizumab (n = 13). We evaluated ADAMTS13-related parameters at onset and once a week until day 28 after the first TPE. The number of days until the platelet counts reached ≥150 × 109/L was significantly shorter in the caplacizumab group than in the non-caplacizumab group. The median ADAMTS13 activity levels on days 14, 21, and 28 were significantly lower in the caplacizumab group. The median titers of the ADAMTS13 inhibitor and anti-ADAMTS13 IgG on the same days were significantly higher in the caplacizumab group. Furthermore, the median number of days from the first TPE until finally achieving an ADAMTS13 activity of ≥10% was significantly longer in the caplacizumab group than in the non-caplacizumab group (42 vs 23 days, P = .014). We observed delayed ADAMTS13 activity recovery and continued inhibitor and anti-ADAMTS13 IgG detection in patients with acute iTTP on caplacizumab, possibly because of the decreased number of TPEs and delayed frontline rituximab.

ADAMTS13 regulates angiogenic markers via Ephrin/Eph signaling in human mesenchymal stem cells under serum-deprivation stress.

Mesenchymal stem cells (MSCs) are known to facilitate angiogenesis and promote neo-vascularization via secretion of trophic factors. Here, we explored the molecular mechanism adopted by ADAMTS13 in modulating the expression of some key angiogenic markers in human umbilical cord-derived MSCs under serum-deprivation stress. Wharton's jelly MSCs (WJ-MSCs) were isolated from the perivascular region of human umbilical cords by explant culture. ADAMTS13 was upregulated at both mRNA and protein levels in WJ-MSCs under serum-deprivation stress. Correspondingly, some key angiogenic markers were also seen to be upregulated. By screening signaling pathways, p38 and JNK pathways were identified as negative and positive regulators for expression of ADAMTS13, and the angiogenic markers, respectively. Our results also indicated the Notch pathway and p53 as other probable partners modulating the expression of ADAMTS13 and the angiogenic markers. Knockdown of ADAMTS13 using siRNA led to reversal in the expression of these angiogenic markers. Further, ADAMTS13 was shown to act via the EphrinB2/EphB4 axis followed by ERK signaling to control expression of the angiogenic markers. Interestingly, stronger expression levels were noted for ADAMTS13, VEGF and PDGF under a more stringent nutrient stress condition. Thus, we highlight a novel role of ADAMTS13 in WJ-MSCs under nutrient stress condition.

Plasmin-cleaved von Willebrand factor as a biomarker for microvascular thrombosis.

ABSTRACT: von Willebrand factor (VWF) is an essential contributor to microvascular thrombosis. Physiological cleavage by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) limits its prothrombotic properties, explaining why ADAMTS13 deficiency leads to attacks of microthrombosis in patients with thrombotic thrombocytopenic purpura (TTP). We previously reported that plasminogen activation takes place during TTP attacks in these patients. Furthermore, stimulation of plasminogen activation attenuates pathogenesis in preclinical TTP models in vivo. This suggests that plasmin is an endogenous regulator of VWF thrombogenicity, in particular when ADAMTS13 falls short to prevent microvascular occlusions. VWF cleavage by plasmin is biochemically distinct from cleavage by ADAMTS13. We hypothesized that plasmin-cleaved VWF (cVWF) holds value as a biomarker of microvascular thrombosis. Here, we describe the development of a variable domain of heavy-chain-only antibody (VHH)-based bioassay that can distinguish cVWF from intact and ADAMTS13-cleaved VWF in plasma. We validate this assay by tracking cVWF release during degradation of microthombi in vitro. We demonstrate that endogenous cVWF formation takes place in patients with TTP during acute attacks of thrombotic microangiopathy but not in those in remission. Finally, we show that therapeutic plasminogen activation in a mouse model of TTP amplifies cVWF formation, which is accompanied by VWF clearance. Our combined findings indicate that cVWF is released from microthrombi in the context of microvascular occlusion.

Histone content, and thus DNA content, is associated with differential in vitro lysis of acute ischemic stroke clots.

BACKGROUND: Fibrin, von Willebrand factor, and extracellular DNA from neutrophil extracellular traps all contribute to acute ischemic stroke thrombus integrity. OBJECTIVES: In this study, we explored how the proteomic composition of retrieved thromboemboli relates to susceptibility to lysis with distinct thrombolytics. METHODS: Twenty-six retrieved stroke thromboemboli were portioned into 4 segments, with each subjected to 1 hour of in vitro lysis at 37 °C in 1 of 4 solutions: tissue plasminogen activator (tPA), tPA + von Willebrand factor-cleaving ADAMTS-13, tPA + DNA-cleaving deoxyribonuclease (DNase) I, and all 3 enzymes. Lysis, characterized by the percent change in prelysis and postlysis weight, was compared across the solutions and related to the corresponding abundance of proteins identified on mass spectrometry for each of the thromboemboli used in lysis. RESULTS: Solutions containing DNase resulted in approximately 3-fold greater thrombolysis than that with the standard-of-care tPA solution (post hoc Tukey, P < .01 for all). DNA content was directly related to lysis in solutions containing DNase (Spearman's ρ > 0.39 and P < .05 for all significant histones) and inversely related to lysis in solutions without DNase (Spearman's ρ < -0.40 and P < .05 for all significant histones). Functional analysis suggests distinct pathways associated with susceptibility to thrombolysis with tPA (platelet-mediated) or DNase (innate immune system-mediated). CONCLUSION: This study demonstrates synergy of DNase and tPA in thrombolysis of stroke emboli and points to DNase as a potential adjunct to our currently limited selection of thrombolytics in treating acute ischemic stroke.

ADAMTS13 recovery in acute thrombotic thrombocytopenic purpura after caplacizumab therapy.

ABSTRACT: Caplacizumab prevents the interaction between von Willebrand factor and platelets and is used to treat immune thrombotic thrombocytopenic purpura (iTTP). Its administration has been associated with a delay in ADAMTS13 activity restoration after plasma exchange (PEX) suspension. We analyzed the outcomes of 113 iTTP episodes, 75 of which were treated with caplacizumab, in 108 patients from the Spanish Registry of Thrombotic Thrombocytopenic Purpura. Caplacizumab shortened the time to platelet count normalization and reduced PEX requirement, exacerbations, and relapses. There was no difference in the time to achieve ADAMTS13 activity ≥20% after PEX end between caplacizumab-treated and nontreated episodes (median [interquartile range], 14.5 [7.7-27.2] vs 13.0 [8.0-29.0] days, P = .653). However, considering the 36 episodes in which caplacizumab was started ≤3 days after iTTP diagnosis, the time for ADAMTS13 restoration from PEX end was higher than in those episodes in which caplacizumab was started >3 days after iTTP diagnosis (20.0 [12.0-43.0] vs 11.0 [3.5-20.0] days, P = .003) or than in non-caplacizumab-treated episodes (P = .033). This finding could be related to a significantly shorter duration of PEX in early caplacizumab-treated episodes than in late caplacizumab-treated episodes (5.5 [4.0-9.0] vs 15.0 [11.0-21.5] days, P < .001) or non-caplacizumab-treated episodes (11.0 [6.0-26.0] days, P < .001). There were no differences in time to ADAMTS-13 restoration from PEX start (28.0 [17.2-47.5], 27.0 [19.0-37.5] and 29.5 [15.2-45.0] days in early caplacizumab-treated, late caplacizumab-treated and non-caplacizumab-treated episodes). Early administered caplacizumab does not prevent the requirement for immunosuppression but has beneficial effects by shortening PEX requirement without major safety concerns.

ADAMTS13 inhibits H2O2-induced human venous endothelial cell injury to attenuate deep-vein thrombosis by blocking the p38/ERK signaling pathway.

Deep vein thrombosis (DVT) is a common complication in hematologic malignancies and immunologic disorders. Endothelial cell injury and dysfunction comprise the critical contributor for the development of DVT. A disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13), a plasma metalloprotease that cleaves von Willebrand factor, acts as a critical regulator in normal hemostasis. This study was aimed to explore the role of ADAMTS13 in endothelial cell injury during DVT and the possible mechanism. First, human umbilical vein endothelial cells (HUVECs) were exposed to hydrogen peroxide (H2O2). Then, the mRNA and protein expressions of ADAMTS13 were evaluated with the reverse transcription-quantitative polymerase chain reaction and western blot. After treatment with recombinant ADAMTS13 (rADAMTS13; rA13), the viability and apoptosis of H2O2-induced HUVECs were assessed by cell counting kit-8 assay and terminal-deoxynucleoitidyl transferase-mediated nick end labeling staining. In addition, the levels of prostaglandin F1-alpha, endothelin-1, and reactive oxygen species were detected using the enzyme-linked immunosorbent assay and dichloro-dihydro-fluorescein diacetate assay. The expressions of proteins related to p38/extracellular signal-regulated kinase (ERK) signaling pathway were estimated with the western blot. Then, p79350 (p38 agonist) was used to pretreat cells to analyze the regulatory effects of rA13 on p38/ERK signaling in H2O2-induced HUVEC injury. The results revealed that ADAMTS13 expression was significantly downregulated in H2O2-induced HUVECs. The reduced viability and increased apoptosis of HUVECs induced by H2O2 were revived by ADAMTS13. ADAMTS13 also suppressed the oxidative stress in HUVECs after H2O2 treatment. Besides, ADAMTS13 was found to block p38/ERK signaling pathway, and p79350 reversed the impacts of ADAMTS13 on the damage of HUVECs induced by H2O2. To sum up, ADAMTS13 could alleviate H2O2-induced HUVEC injury through the inhibition of p38/ERK signaling pathway.

ADAMTS-13 and HMGB1-induced oxidative stress in Taenia multiceps-infected animals.

This study investigated the cytotoxic effects of oxidative stress (OS), high mobility group box 1 (HMGB1), ADAMTS (A disintegrin and metalloproteinase with thrombospondin motifs), and neuropathology associated with coenurus cerebralis (Taenia multiceps). ADAMTS-13, HMGB1, glutathione reductase (GR), copper/zinc superoxide dismutase (Cu/Zn SOD), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) expression levels were studied. The study found that ADAMTS-13 (P < 0.005), HMGB1 (P < 0.005), GR (P < 0.005), Cu/Zn SOD (P < 0.005), and 8-OHdG (P < 0.005) levels were significantly higher in T. multiceps (c. cerebralis)-infected animals compared to healthy control animals. This study's most important finding was that HMGB1 up-regulation in neurons, endothelial cells, and glial cells can directly cause brain parenchymal destruction and that HMGB1-mediated oxidative stress plays a crucial role in the neuropathogenesis of coenurosis. The results also showed that increased levels of ADAMTS-13 may play a pivotal role in regulating and protecting the blood-brain barrier integrity and neuroprotection. These findings also suggest that ADAMTS-13 and HMGB1 compete in the prevention or formation of microthrombi, which was regarded as a remarkable finding. ADAMTS-13 and HMGB1 are valuable biomarkers for disease risk assessment, estimating host neuropathy following T. multiceps (c. cerebralis) exposure, and providing a new therapeutic target. This is the first study to show that HMGB1 and ADAMTS-13 are expressed in reactive cells and are associated with neuroimmunopathology in coenurosis.