In resting platelets, the 17 ^th domain of filamin a (FLNa17) constitutively binds to the platelet membrane glycoprotein Ibα (GPIbα) at its cytoplasmic tail (GPIbα-CT) and inhibits the downstream signal activation, while the binding of ligand and blood shear force can activate platelets. To imitate the pull force transmitted from the extracellular ligand of GPIbα and the lateral tension from platelet cytoskeleton deformation, two pulling modes were applied on the GPIbα-CT/FLNa17 complex, and the molecular dynamics simulation method was used to explore the mechanical regulation on the affinity and mechanical stability of the complex. In this study, at first, nine pairs of key hydrogen bonds on the interface between GPIbα-CT and FLNa17 were identified, which was the basis for maintaining the complex structural stability. Secondly, it was found that these hydrogen bonding networks would be broken down and lead to the dissociation of FLNa17 from GPIbα-CT only under the axial pull force; but, under the lateral tension, the secondary structures at both terminals of FLNa17 would unfold to protect the interface of the GPIbα-CT/FLNa17 complex from mechanical damage. In the range of 0~40 pN, the increase of pull force promoted outward-rotation of the nitrogen atom of the 563 ^rd phenylalanine (PHE ⁵⁶³-N) at GPIbα-CT and the dissociation of the complex. This study for the first time revealed that the extracellular ligand-transmitted axial force could more effectively relieve the inhibition of FLNa17 on the downstream signal of GPIbα than pure mechanical tension at the atomic level, and would be useful for further understanding the platelet intracellular force-regulated signal pathway.
Filamins/metabolism* ; Platelet Glycoprotein GPIb-IX Complex/metabolism* ; Molecular Dynamics Simulation ; Ligands ; Protein Binding ; Blood Platelets/metabolism* ; von Willebrand Factor/metabolism*

OBJECTIVES: To explore the role and potential mechanisms of chitinase-3-like protein 1 (CHI3L1) in coronary artery lesions in a mouse model of Kawasaki disease (KD)-like vasculitis. METHODS: Four-week-old male SPF-grade C57BL/6 mice were randomly divided into a control group and a model group, with 10 mice in each group. The model group mice were intraperitoneally injected with 0.5 mL of lactobacillus casei cell wall extract (LCWE) to establish a mouse model of KD-like vasculitis, while the control group mice were injected with an equal volume of normal saline. The general conditions of the mice were observed on the 3rd, 7th, and 14th day after injection. Changes in coronary artery tissue pathology were observed using hematoxylin-eosin staining. The level of CHI3L1 in mouse serum was measured by enzyme-linked immunosorbent assay. Immunofluorescence staining was used to detect the expression and localization of CHI3L1, von Willebrand factor (vWF), and α-smooth muscle actin (α-SMA) in coronary artery tissue. Western blot analysis was used to detect the expression of CHI3L1, vWF, vascular endothelial cadherin (VE cadherin), Caspase-3, B cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), nuclear factor κB (NF-κB), and phosphorylated NF-κB (p-NF-κB) in coronary artery tissue. RESULTS: The serum level of CHI3L1 in the model group was significantly higher than that in the control group (P<0.05). Compared to the control group, the expression of CHI3L1 in the coronary artery tissue was higher, while the expression of vWF was lower in the model group. The relative expression levels of CHI3L1, Bax, Caspase-3, NF-κB, and p-NF-κB were significantly higher in the model group than in the control group (P<0.05). The relative expression levels of vWF, VE cadherin, and Bcl-2 were lower in the model group than in the control group (P<0.05). CONCLUSIONS In the LCWE-induced mouse model of KD-like vasculitis, the expression levels of CHI3L1 in serum and coronary arteries increase, and it may play a role in coronary artery lesions through endothelial cell apoptosis mediated by inflammatory reactions.
Male ; Animals ; Mice ; Mucocutaneous Lymph Node Syndrome/pathology* ; Coronary Vessels/pathology* ; NF-kappa B ; Caspase 3/metabolism* ; bcl-2-Associated X Protein/metabolism* ; Chitinase-3-Like Protein 1 ; von Willebrand Factor/metabolism* ; Mice, Inbred C57BL ; Cadherins

OBJECTIVE: To develop monoclonal antibodies that can specifically recognize human von Willebrand factor (VWF) propeptide (VWFpp) in plasma, and establish a rapid and reliable method for the detection of VWFpp antigen in plasma by using the double-antibody sandwich ELISA with the obtained anti-VWFpp monoclonal antibody. METHODS: The recombinant human VWFpp (D1 and D2 regions) protein expressed in eukaryotic cells was used as immunogen to immunize BALB/c mice with routine method, so as to obtain clones of fusion cells. After screening and identification, hybridoma cell lines secreting monoclonal antibodies against VWFpp were selected, and then double-antibody sandwich ELISA assay was used to construct VWFpp antigen detection kit for the determination of VWFpp in human plasma. The levels of VWFpp antigen in plasma of 12 leukemia patients who underwent bone marrow transplantation were dynamically detected. RESULTS: Two hybridoma cell lines that can be subcultured continuously and secrete monoclonal antibodies against VWFpp were obtained and named SZ175 and SZ176 respectively. Identified by ELISA and Western blot, the antibodies could both specifically recognize VWFpp but couldn't recognize mature VWF (without propeptide). Based on the principle of double-antibody sandwich ELISA, monoclonal antibodies SZ175 and SZ176 were successfully made into a kit for detecting VWFpp antigen. The plasma VWFpp levels of leukemia patients before and after bone marrow transplantation were dynamically detected. The results showed that the plasma VWFpp levels of the patients after transplantation were significantly higher than those before transplantation. CONCLUSION Two monoclonal antibodies against VWFpp were successfully prepared, and a double-antibody sandwich ELISA detection kit for VWFpp antigen was constructed, which provides a powerful tool for further study on the biological function of VWFpp, the clinical diagnosis and classification of von Willebrand disease (VWD), and the prognostic monitoring of endothelial injury-related diseases.
Animals ; Mice ; Humans ; von Willebrand Factor ; Antibodies, Monoclonal ; Protein Precursors/metabolism* ; von Willebrand Diseases/diagnosis* ; Prognosis

OBJECTIVE: To dynamically observe the levels and activities of von Willebrand factor (vWF) and ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) in plasma of children with congenital ventricular septal defect (VSD) during perioperative period, and explore the value of plasma vWF antigen (vWF:Ag) and ADAMTS-13 activity (ADAMTS-13: AC) in evaluating vascular endothelial injury and prognosis in children with VSD. METHODS: In this cross-sectional study, a total of 74 children with VSD who underwent surgical treatment in TEDA International Cardiovascular Hospital from September 2018 to March 2019 were enrolled in the observation group. Among them, there were 28 cases of pure VSD, 32 cases of VSD combined with pulmonary hypertension, and 14 cases of VSD combined with valvular heart disease. 31 healthy children who underwent physical examination in Tianjin Children's Hospital during the same period were collected as the control group. The biochemical indexes of the children at admission were recorded. Peripheral plasma was collected at admission, postsurgery day 0 and day 1, respectively, and the levels of vWF activity (vWF:AC), vWF:Ag, ADAMTS-13 antigen (ADAMTS-13:Ag) and ADAMTS-13:AC were detected. RESULTS: The level of plasma vWF:Ag and vWF:AC in the observation group before surgery were significantly lower than those in the control group (P<0.001), and increased continuously, on postsurgery day 0 and day 1 (P<0.001). The level of ADAMTS-13:Ag in the observation group before surgery was significantly higher than that in the control group (P<0.001), which decreased significantly on postsurgery day 0 (P<0.001), and increased significantly on postsurgery day 1 compared with postsurgery day 0 (P=0.033). The level of ADAMTS-13:AC in the observation group before surgery was significantly lower than that in the control group (P=0.015), which decreased significantly on postsurgery day 0 (P=0.037), and increased on postsurgery day 1, but the difference was not statistically significant (P=0.051). The changes of vWF and ADAMTS-13 in the three subgroups were basically similar to the observation group. vWF: Ag/ADAMTS-13: AC ratio on postsurgery day 0 and day 1 had high diagnostic value in vascular endothelial injury (AUC=0.80, P<0.001; AUC=0.93, P<0.001). Preoperative vWF and ADAMTS-13 levels, and related baseline indicators were not correlated with postoperative infection, bleeding, thrombosis,etc. CONCLUSION Preoperative vWF: Ag, vWF: AC and ADAMTS-13: AC levels in children with VSD are low, while the level of ADAMTS-13: Ag is high. After surgery, the levels of vWF: Ag and vWF: AC are increased and the level of ADAMTS-13: Ag is decreased. The postoperative vWF: Ag/ADAMTS-13: AC ratio shows high diagnostic value in evaluating vascular endothelial injury. There is no correlation between preoperative vWF and ADAMTS-13 levels with perioperative clinical events.
Child ; Humans ; ADAMTS13 Protein ; Cross-Sectional Studies ; Heart Septal Defects, Ventricular ; Prognosis ; von Willebrand Factor

Congenital thrombotic thrombocytopenic purpura, also known as Upshaw-Schulman syndrome, is a rare autosomal recessive genetic disorder. The main pathogenesis is homozygous or compound heterozygous variants of von Willebrand factor lyase (ADAMTS13) gene mapped to chromosome 9q34, which may result in severe lack of ADAMTS13 which cleaves von Willebrand factor (vWF) multimers in the plasma and increase the risk of microvascular thrombosis, leading to various complications. The advance of research on the pathogenesis of cTTP, recombinant human ADAMTS13 and gene therapy have made breakthroughs which may lead to cure of cTTP. This article has provided a review for the latest progress made in the diagnosis and treatment of cTTP.
ADAM Proteins/genetics* ; ADAMTS13 Protein/genetics* ; Homozygote ; Humans ; Purpura, Thrombotic Thrombocytopenic/therapy* ; von Willebrand Factor/genetics*

OBJECTIVES: To study the biological processes and functions of serum exosomes in children in the acute stage of Kawasaki disease (KD), so as to provide new biomarkers for the early diagnosis of KD. METHODS: In this prospective study, 13 children with KD who were treated in Children's Hospital of Soochow University from June 2019 to August 2020 were enrolled as the KD group, and 13 children who were hospitalized due to bacterial infection during the same period were enrolled as the control group. Whole blood was collected on the next morning after admission, serum samples were obtained by centrifugation, and exosomes were extracted through ultracentrifugation. Serum exosomes were analyzed by label-free quantitative proteomics, and differentially expressed proteins (DEPs) were screened out for functional enrichment analysis. A protein-protein interaction (PPI) network was plotted, and unique proteins were validated by targeted proteomics. RESULTS: A total of 131 DEPs were screened out for the two groups, among which 27 proteins were detected in both groups. There were 48 unique DEPs in the KD group, among which 23 were upregulated and 25 were downregulated, and these proteins acted on "complement and coagulation cascades" and "the MAPK signaling pathway". Validation by targeted proteomics showed that FGG, SERPING1, C1R, C1QA, IGHG4, and C1QC proteins were quantifiable in the KD group. A total of 29 proteins were only expressed in the control group, among which 12 were upregulated and 17 were downregulated. Four proteins were quantifiable based on targeted proteomics, i.e., VWF, ECM1, F13A1, and TTR. A PPI network was plotted for each group. In the KD group, FGG and C1QC had close interaction with other proteins, while in the control group, VWF had close interaction with other proteins. CONCLUSIONS The serum exosomes FGG and C1QC in children in the acute stage of KD are expected to become the biomarkers for the early diagnosis of KD. For children with unexplained fever, detection of FGG, C1QC1, and VWF may help with etiological screening.
Biomarkers ; Child ; Exosomes ; Extracellular Matrix Proteins ; Humans ; Mucocutaneous Lymph Node Syndrome/diagnosis* ; Prospective Studies ; Proteomics ; von Willebrand Factor

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy, in which a severe deficiency of von Willebrand factor lyase results in thrombocytopenic clots that block blood vessels and eventually lead to terminal organ failure. Therapeutic plasma exchange is the cornerstone of TTP treatment which can greatly improves the survival rate of the patients. With the further exploration to the pathophysiological mechanism of TTP, other alternative therapies, new immunosuppressive agents, targeted antagonists, gene therapy and other emerging means gradually emerge, which are expected to further reduce the mortality and recurrence rate of the patients. In this review, the new developments in TTP treatment were summarized briefly.
ADAMTS13 Protein ; Humans ; Immunosuppressive Agents ; Plasma Exchange ; Purpura, Thrombotic Thrombocytopenic/therapy* ; von Willebrand Factor

Asians ; China ; Humans ; von Willebrand Diseases/therapy* ; von Willebrand Factor

Asians ; China ; Humans ; von Willebrand Diseases/therapy* ; von Willebrand Factor

OBJECTIVE: To explore the correlation of coagulation function with the severity and prognosis of acute pancreatitis (AP) and identify the laboratory markers for early prediction and dynamic monitoring of the prognosis of AP. METHODS: We retrospectively analyzed the clinical data of patients with AP admitted less than 72 h after onset to our hospital from December 1, 2017 to November 30, 2018. The correlation of coagulation function-related markers at admission and their changes during hospitalization with the prognosis of the patients was analyzed. RESULTS: We screened the data of a total of 1260 patients with AP against the inclusion and exclusion criteria, and eventually 175 patients were enrolled in this analysis, among whom 52 patients had severe AP (SAP) and 12 patients died. Logistic regression analysis identified vWF: Ag, PT, PC, AT Ⅲ and D-dimer markers at admission as independent risk factors for predicting SAP and death. Dynamic monitoring of the changes in coagulation function-related markers in the disease course had greater predictive value of the patients' prognosis, and the indicators including vWF: Ag_max, PT_max, APTT_max, TT_max, FIB_min, D-dimer_max, PLT_min, PC_min, PLG_min, AT Ⅲ_min, and their variations were all independent risk factors for predicting SAP and death. ROC analysis suggested that dynamic monitoring of the changes in the indicators, especially those of △vWF: Ag, △PT, △APTT, △FIB, △TT, △D-dimer, △PLT, △PC, △AT Ⅲ, △PLG, could effectively predict SAP and death in these patients (with AUC range of 0.63-0.84). CONCLUSION Patients with AP have vascular endothelial injuries and coagulation disorders. The markers including vWF: Ag, PT, PC, AT Ⅲ and D-dimer at admission are independent risk factors for predicting SAP and death, and dynamic monitoring of the changes in vWF: Ag、PT、APTT、TT、FIB、D-dimer、PLT、PC、AT Ⅲ and PLG can further increase the predictive value.
Acute Disease ; Biomarkers ; Humans ; Pancreatitis/diagnosis* ; Prognosis ; ROC Curve ; Retrospective Studies ; Severity of Illness Index ; von Willebrand Factor