Expression Of Von Willebrand Factor Research Articles

The impact of hsa-miR-1972 on the expression of von Willebrand factor in breast cancer progression regulation.

Breast cancer (BC) is one of most frequent female malignancies that poses multiple challenges in treatment and prevention. This study aimed to explore the role of miRNAs and their target genes during the BC progression. Based on the BC data (113 normal and 1,118 tumor samples) from the TCGA-BRCA dataset, a single-sample gene set enrichment analysis (ssGSEA) was applied to calculate the cancer migration scores, and weighted gene co-expression network analysis (WGCNA) were performed using the WGCNA R package, with a focus on the set of genes associated with cancer migration. Key modules and hub genes related to cell migration and signaling pathways were identified. Survival analysis of hub genes was conducted using the survminer R package, and prediction of regulatory miRNAs were performed to analyze their impact on BC prognosis. In addition, the BC cell lines MCF-7 and MDA-MB-231 were used to further explore the effect of hsa-miR-1972 mimics on the gene expression and angiogenic factor regulation. The study classified important modules (MEblue, MEmagenta, MEpink, and MEfloralwhite) associated with cell migration and identified three hub genes, namely, MRPL20, COL4A1 and VWF. Survival analysis showed that certain hub genes with a low expression were related to a poor prognosis, whereas low-expressed COL4A1 and VWF were related to better survival outcomes. We also found that hsa-miR-1972 mimics significantly downregulated critical genes involved in BC metastasis and angiogenesis and effectively inhibited the proliferation of BC cell lines, showing a strong therapeutic potential. Manipulation of VWF expression in cells overexpressing hsa-miR-1972 had significant effects on the malignant markers and angiogenic factors, suggesting a novel therapeutic direction for BC treatment. Our study highlighted the complex interplay of genetic factors in BC progression as well as the therapeutic potential of targeting specific miRNAs and their related hub genes. These findings provided novel insights into the pathogenesis of BC and suggested new direction for the therapeutic development for the cancer.

Revisiting Virchow’s triad: exploring the cellular and molecular alterations in cerebral venous congestion

BackgroundCerebral venous thrombosis (CVT) is a rare but serious condition that can lead to significant morbidity and mortality. Virchow’s triad elucidates the role of blood hypercoagulability, blood flow dynamics, and endothelial damage in the pathogenesis of CVT. Cerebral venous congestion (CVC) increases the risk of cerebral venous sinus thrombosis and can lead to recurrent episodes and residual symptoms. However, the precise mechanism by which blood congestion leads to thrombosis remains unclear. Our objective was to investigate the cellular and molecular alterations linked to CVC through analysis of the pathological morphology of venous sinus endothelial cells and transcriptomic profiling.ResultsThis study demonstrated a remarkable correlation between CVC and the phenotypic transformation of endothelial cells from an anticoagulant to a procoagulant state. The findings revealed that cerebral venous stasis results in tortuous dilatation of the venous sinuses, with slow blood flow and elevated pressure in the sinuses and damaged endothelial cells of the retroglenoid and internal jugular vein ligation (JVL) rat model. Mechanistically, analysis of transcriptomic results of cerebral venous sinus endothelial cells showed significant activation of platelet activation, complement and coagulation cascades pathway in the JVL rats. Furthermore, the expression of von Willebrand factor (vWF) and coagulation factor VIII (F8) in the complement and coagulation cascades and Fgg and F2 in the platelet activation was increased in the cerebral venous sinuses of JVL rats than in sham rats, suggesting that endothelial cell injury in the venous sinus induced by CVC has a prothrombotic effect. In addition, endothelial cell damage accelerates coagulation and promotes platelet activation. Significantly, the concentrations of vWF, F2 and F8 in venous sinus blood of patients with internal jugular vein stenosis were higher than in their peripheral blood.ConclusionCollectively, our data suggest that CVC can induce endothelial cell damage, which then exhibits a procoagulant phenotype and ultimately increases the risk of CVT. This research contributes to our understanding of the pathophysiology of CVC associated with procoagulant factors and reexamines the components of Virchow’s triad in the context of CVC.

Evaluating the Role of Silymarin in Coordinating the Relationship between Inflammation and Thrombosis by Affecting Endothelial Cells

Background: A widespread crosstalk between inflammation and coagulation has been shown in numerous studies. This suggests that coagulation can trigger an inflammatory response which ultimately leads to coagulation activation. Previous research has shown that polyphenols can affect blood pressure and endothelial dysfunction, resulting in reduced risk of cardiovascular diseases. This study aimed to investigate whether Silymarin, a flavonolignans, could play a role in the interaction between inflammation and coagulation by influencing endothelial cells. Materials and Methods: In this experimental study, human umbilical vein endothelial cells (HUVECs) were seeded with and without various concentrations of silymarin. In vivo, treatment with silymarin was also carried out. Coagulative and fibrinolytic factors, including Von Willebrand factor (VWF) and Factor VIII (FVIII), tissue plasminogen activator-1 (TPA-1), and inflammatory factors, including interleukin 8 (IL-8) and tumor necrosis factor-alpha (TNF-α), were evaluated by flow cytometry, Real-Time Polymerase Chain Reaction (qPCR), Enzyme-Linked Immunosorbent Assay (ELISA) and Immunocytochemistry (ICC). Results: Silymarin increased the gene expression, release, and storage of VWF while diminishing the gene expression, release, and storage of TPA-1 (P ˂ 0.05). The activity of FVIII was dramatically increased, and IL-8 and TNF-α levels were augmented. The in vivo study also indicated an elevated plasma level of VWF and IL-8 by silymarin administration. Conclusion: The results showed that, although silymarin reduces inflammatory factors, it can affect coagulation factors by increasing the levels of VWF and FVIII activity and inhibiting TPA-1 production, thereby making thrombosis probable. Consequently, it is advisable to prescribe this medication with caution for individuals who are susceptible to thrombotic events.

Hybrid biofabricated blood vessel for medical devices testing

ABSTRACT Current in vitro and in vivo tests applied to assess the safety of medical devices retain several limitations, such as an incomplete ability to faithfully recapitulate human features, and to predict the response of human tissues together with non-trivial ethical aspects. We here challenged a new hybrid biofabrication technique that combines bioprinting and Fast Diffusion-induced Gelation strategy to generate a vessel-like structure with the attempt to spatially organize fibroblasts, smooth-muscle cells, and endothelial cells. The introduction of Fast Diffusion-induced Gelation minimizes the endothelial cell mortality during biofabrication and produce a thin endothelial layer with tunable thickness. Cell viability, Von Willebrand factor, and CD31 expression were evaluated on biofabricated tissues, showing how bioprinting and Fast Diffusion-induced Gelation can replicate human vessels architecture and complexity. We then applied biofabricated tissue to study the cytotoxicity of a carbothane catheter under static condition, and to better recapitulate the effect of blood flow, a novel bioreactor named CuBiBox (Customized Biological Box) was developed and introduced in a dynamic modality. Collectively, we propose a novel bioprinted platform for human in vitro biocompatibility testing, predicting the impact of medical devices and their materials on vascular systems, reducing animal experimentation and, ultimately, accelerating time to market.

Regulation of osteogenesis and angiogenesis by cobalt, manganese and strontium doped apatitic materials for functional bone tissue regeneration

Strontium, cobalt, and manganese ions are present in the composition of bone and useful for bone metabolism, even when combined with calcium phosphate in the composition of biomaterials. Herein we explored the possibility to include these ions in the composition of apatitic materials prepared through the cementitious reaction between ion-substituted calcium phosphate dibasic dihydrate, CaHPO4·2H2O (DCPD) and tetracalcium phosphate, Ca4(PO4)2O (TTCP). The results of the chemical, structural, morphological and mechanical characterization indicate that cobalt and manganese exhibit a greater delaying effect than strontium (about 15 at.%) on the cementitious reaction, even though they are present in smaller amounts within the materials (about 0.8 and 4.5 at.%, respectively). Furthermore, the presence of the foreign ions in the apatitic materials leads to a slight reduction of porosity and to enhancement of compressive strength. The results of biological tests show that the presence of strontium and manganese, as well as calcium, in the apatitic materials cultured in direct contact with human mesenchymal stem cells (hMSCs) stimulates their viability and activity. In contrast, the apatitic material containing cobalt exhibits a lower metabolic activity. All the materials have a positive effect on the expression of Vascular Endothelial Growth Factor (VEGF) and Von Willebrand Factor (vWF). Moreover, the apatitic material containing strontium induces the most significant reduction in the differentiation of preosteoclasts into osteoclasts, demonstrating not only osteogenic and angiogenic properties, but also ability to regulate bone resorption.

Distinct profile of antiviral drugs effects in aortic and pulmonary endothelial cells revealed by high-content microscopy and cell painting assays

Antiretroviral therapy have significantly improved the treatment of viral infections and reduced the associated mortality and morbidity rates. However, highly effective antiretroviral therapy (HAART) may lead to an increased risk of cardiovascular diseases, which could be related to endothelial toxicity. Here, seven antiviral drugs (remdesivir, PF-00835231, ritonavir, lopinavir, efavirenz, zidovudine and abacavir) were characterized against aortic (HAEC) and pulmonary (hLMVEC) endothelial cells, using high-content microscopy.The colourimetric study (MTS test) revealed similar toxicity profiles of all antiviral drugs tested in the concentration range of 1 nM–50 μM in aortic and pulmonary endothelial cells. Conversely, the drugs' effects on morphological parameters were more pronounced in HAECs as compared with hLMVECs. Based on the antiviral drugs' effects on the cytoplasmic and nuclei architecture (analyzed by multiple pre-defined parameters including SER texture and STAR morphology), the studied compounds were classified into five distinct morphological subgroups, each linked to a specific cellular response profile. In relation to morphological subgroup classification, antiviral drugs induced a loss of mitochondrial membrane potential, elevated ROS, changed lipid droplets/lysosomal content, decreased von Willebrand factor expression and micronuclei formation or dysregulated cellular autophagy.In conclusion, based on specific changes in endothelial cytoplasm, nuclei and subcellular morphology, the distinct endothelial response was identified for remdesivir, ritonavir, lopinavir, efavirenz, zidovudine and abacavir treatments. The effects detected in aortic endothelial cells were not detected in pulmonary endothelial cells. Taken together, high-content microscopy has proven to be a robust and informative method for endothelial drug profiling that may prove useful in predicting the organ-specific endothelial toxicity of various drugs.

Dexmedetomidine ameliorates x-ray-induced myocardial injury via alleviating cardiomyocyte apoptosis and autophagy

BackgroundRadiotherapy is a primary local treatment for tumors, yet it may lead to complications such as radiation-induced heart disease (RIHD). Currently, there is no standardized approach for preventing RIHD. Dexmedetomidine (Dex) is reported to have cardio-protection effects, while its role in radiation-induced myocardial injury is unknown. In the current study, we aimed to evaluate the radioprotective effect of dexmedetomidine in X-ray radiation-treated mice.Methods18 male mice were randomized into 3 groups: control, 16 Gy, and 16 Gy + Dex. The 16 Gy group received a single dose of 16 Gy X-ray radiation. The 16 Gy + Dex group was pretreated with dexmedetomidine (30 µg/kg, intraperitoneal injection) 30 min before X-ray radiation. The control group was treated with saline and did not receive X-ray radiation. Myocardial tissues were collected 16 weeks after X-ray radiation. Hematoxylin-eosin staining was performed for histopathological examination. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining was performed to assess the state of apoptotic cells. Immunohistochemistry staining was performed to examine the expression of CD34 molecule and von Willebrand factor. Besides, western blot assay was employed for the detection of apoptosis-related proteins (BCL2 apoptosis regulator and BCL2-associated X) as well as autophagy-related proteins (microtubule-associated protein 1 light chain 3, beclin 1, and sequestosome 1).ResultsThe findings demonstrated that 16 Gy X-ray radiation resulted in significant changes in myocardial tissues, increased myocardial apoptosis, and activated autophagy. Pretreatment with dexmedetomidine significantly protects mice against 16 Gy X-ray radiation-induced myocardial injury by inhibiting apoptosis and autophagy.ConclusionIn summary, our study confirmed the radioprotective effect of dexmedetomidine in mitigating cardiomyocyte apoptosis and autophagy induced by 16 Gy X-ray radiation.

New targets for the prevention and treatment of cirrhotic portal vein thrombosis

Portal vein thrombosis (PVT) is divided into cirrhotic and non-cirrhotic PVTs. The incidence rate of PVT varies greatly among different clinical stages of cirrhosis, with an overall incidence rate of about 13.92%, and the prevalence of cirrhotic PVT following splenectomy is as high as 60%. The pathogenesis of cirrhotic PVT is still unclear. However, the activation of Janus kinase/signal transduction and activator transcription signaling pathways, the rise in the expression of von Willebrand factor, and the gut microbiota along with its metabolite trimethylamine-N-oxide play an important role in the injury of vascular endothelial cells and the formation of PVT in cirrhosis. Therefore, these could be a new target for cirrhotic PVT prevention and treatment.

Shiga toxin down-regulates ERG protein in endothelial cells and impairs angiogenesis

BackgroundShiga toxin (Stx) can activate inflammatory signaling, leading to vascular dysfunction and promotion of a pro-thrombotic tissue microenvironment. Stx can trigger the development of the enterohemorrhagic (childhood) hemolytic uremic syndrome (eHUS), a triad of thrombocytopenia, hemolytic anemia, and acute kidney injury, often requiring dialysis. Additional features may include damage to other organs, including the gastrointestinal tract, pancreas, brain and cardiovascular system; death occurs in 2–5 %. eHUS is a thrombotic microangiopathy; thus, endothelial cell (EC) injury and platelet fibrin thrombus formation in glomerular arterioles and in the arterioles of other affected organs are likely. To elucidate mechanisms of this microangiopathy, we examined in human ECs the regulation of the platelet adhesion proteins P-selectin and von Willebrand factor (VWF), along with the downregulation of erythroblast-transformation-specific transcription factor (ERG) a key regulator of angiogenesis and megakaryocyte development. MethodsVWF, P-selectin, and ERG levels were determined using immunofluorescence and Western blot in human umbilical endothelial cells (HUVECs). HUVECs were treated with tumor necrosis factor-alpha (TNF-α), Stx-1 or both, versus normal controls. Capillary morphogenesis on Matrigel was performed using HUVECs treated, for 22 h with TNF-α, Stx-1, or both, or treated 4 h with Stx-1 alone or in combination with TNF-α for 22 h. ResultsStx-1 significantly reduced ERG and VWF expression on HUVECs, but upregulated P-selectin expression. ERG levels decreased with Stx-1 alone or in combination with TNF-α, in the nuclear, perinuclear and cytoplasmatic regions. Stx-1 reduced capillary morphogenesis, while Stx-1-TNF-α combined treatment reduced capillary morphogenesis still further. ConclusionsIn the presence of Stx-1 or TNF-α or both treatments, ECs were activated, expressing higher levels of P-selectin and lower levels of VWF. Our findings, further, provide evidence that Stx-1 downregulates ERG, repressing angiogenesis in vitro.

Effect of Xuming Decoction in Records of Proved Prescriptions, Ancient a nd Modern on cerebral ischemic injury and angiogenesis in rat model of acute cerebral infarction

This paper aims to explore the effect of Xuming Decoction in the Records of Proved Prescriptions, Ancient and Modern on cerebral ischemic injury and angiogenesis in the rat model of acute cerebral infarction. SD rats were randomized into 6 groups: sham group, model group, low-, medium-, and high-dose(5.13, 10.26, and 20.52 g·kg~(-1), respectively) Xuming Decoction groups, and butylphthalide(0.06 g·kg~(-1)) group. After the successful establishment of the rat model by middle cerebral artery occlusion(MCAO), rats in the sham and model groups were administrated with distilled water and those in other groups with corresponding drugs for 7 consecutive days. After the neurological function was scored, all the rats were sacrificed, and the brain tissue samples were collected. The degree of cerebral ischemic injury was assessed by the neurological deficit score and staining with 2,3,5-triphenyltetrazolium chloride. Hematoxylin-eosin staining was performed to observe the pathological changes in the brain. Transmission electron microscopy was employed to observe the ultrastructures of neurons and microvascular endothelial cells(ECs) on the ischemic side of the brain tissue. Immunofluorescence assay was employed to detect the expression of von Willebrand factor(vWF) and hematopoietic progenitor cell antigen CD34(CD34) in the ischemic brain tissue. Real-time PCR and Western blot were employed to determine the mRNA and protein levels, respectively, of Runt-related transcription factor 1(RUNX1), vascular endothelial growth factor(VEGF), angiopoietin-1(Ang-1), angiopoietin-2(Ang-2), and VEGF receptor 2(VEGFR2) in the ischemic brain tissue. The results showed that compared with the sham group, the model group showed increased neurological deficit score and cerebral infarction area(P<0.01), pathological changes, and damaged ultrastructure of neurons and microvascular ECs in the ischemic brain tissue. Furthermore, the modeling up-regulated the mRNA levels of RUNX1, VEGF, Ang-1, Ang-2, and VEGFR2(P<0.01) and the protein levels of vWF, CD34, RUNX1, VEGF, Ang-1, Ang-2, and VEGFR2(P<0.05 or P<0.01). Compared with the model group, high-dose Xuming Decoction and butylphthalide decreased the neurological deficit score and cerebral infarction area(P<0.01) and alleviated the pathological changes and damage of the ultrastructure of neurons and microvascular ECs in the ischemic brain tissue. Moreover, they up-regulated the mRNA levels of RUNX1, VEGF, Ang-1, Ang-2, and VEGFR2(P<0.01) and the protein levels of vWF, CD34, RUNX1, VEGF, Ang-1, Ang-2, and VEGFR2(P<0.01). The results suggest that Xuming Decoction in the Records of Proved Prescriptions, Ancient and Modern can promote the angiogenesis and collateral circulation establishment to alleviate neurological dysfunction of the ischemic brain tissue in MCAO rats by regulating the RUNX1/VEGF pathway.

Injectable Tissue-Specific Hydrogel System for Pulp–Dentin Regeneration

The quest for finding a suitable scaffold system that supports cell survival and function and, ultimately, the regeneration of the pulp–dentin complex remains challenging. Herein, we hypothesized that dental pulp stem cells (DPSCs) encapsulated in a collagen-based hydrogel with varying stiffness would regenerate functional dental pulp and dentin when concentrically injected into the tooth slices. Collagen hydrogels with concentrations of 3 mg/mL (Col3) and 10 mg/mL (Col10) were prepared, and their stiffness and microstructure were assessed using a rheometer and scanning electron microscopy, respectively. DPSCs were then encapsulated in the hydrogels, and their viability and differentiation capacity toward endothelial and odontogenic lineages were evaluated using live/dead assay and quantitative real-time polymerase chain reaction. For in vivo experiments, DPSC-encapsulated collagen hydrogels with different stiffness, with or without growth factors, were injected into pulp chambers of dentin tooth slices and implanted subcutaneously in severe combined immunodeficient (SCID) mice. Specifically, vascular endothelial growth factor (VEGF [50 ng/mL]) was loaded into Col3 and bone morphogenetic protein (BMP2 [50 ng/mL]) into Col10. Pulp–dentin regeneration was evaluated by histological and immunofluorescence staining. Data were analyzed using 1-way or 2-way analysis of variance accordingly (α = 0.05). Rheology and microscopy data revealed that Col10 had a stiffness of 8,142 Pa with a more condensed and less porous structure, whereas Col3 had a stiffness of 735 Pa with a loose microstructure. Furthermore, both Col3 and Col10 supported DPSCs’ survival. Quantitative polymerase chain reaction showed Col3 promoted significantly higher von Willebrand factor (VWF) and CD31 expression after 7 and 14 d under endothelial differentiation conditions (P < 0.05), whereas Col10 enhanced the expression of dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and collagen 1 (Col1) after 7, 14, and 21 d of odontogenic differentiation (P < 0.05). Hematoxylin and eosin and immunofluorescence (CD31 and vWF) staining revealed Col10+Col3+DPSCs+GFs enhanced pulp–dentin tissue regeneration. In conclusion, the collagen-based concentric construct modified by growth factors guided the specific lineage differentiation of DPSCs and promoted pulp–dentin tissue regeneration in vivo.

Approaches to induce the maturation process of human induced pluripotent stem cell derived-endothelial cells to generate a robust model.

Endothelial cells generated from induced pluripotent stem cells (hiPSC-ECs) show the majority of endothelial cell characteristics and markers, such as cobblestone morphology and the expression of VEGF and VE-cadherin. However, these cells are failing to show a mature endothelial cell phenotype, which is represented by the low expression and production of von Willebrand Factor (VWF) leading to the round morphology of the Weibel Palade Bodies (WPBs). The aim of this study was to improve the maturation process of hiPSC-ECs and to increase the levels of VWF. hiPSC-ECs were differentiated by a standard differentiation protocol from hiPSCs generated from healthy control donors. To induce maturation, the main focus was to increase the expression and/or production of VWF by the adjustment of potential parameters influencing differentiation and maturation. We also compared alternative differentiation protocols. Cells were analyzed for the expression of endothelial cell markers, WPB structure, and the production and secretion of VWF by flow cytometry, confocal microscopy and ELISA. The generated hiPSC-ECs have typical endothelial cell surface expression profiles, with low expression levels of non-endothelial markers as expected. Co-culture with pericytes, varying concentrations and timing of differentiation factors, applying some level of flow, and the addition of HDAC inhibitors did not substantially improve maturation of hiPSC-ECs. Transfection with the transcription factor ETV2 to induce a faster hiPSC-EC differentiation process resulted in a limited increase in VWF production, secretion, and elongation of WPB structure. Alternative differentiation protocols had limited effect. hiPSCs-ECs have the potential to show a more mature endothelial phenotype with elongated WPBs after >30 days in culture. However, this comes with limitations as there are very few cells detected, and cells are deteriorating after being in culture for extended periods of time.

Coronary microthrombi in the failing human heart: the role of von Willebrand factor and PECAM-1

The recognition of microthrombi in the heart microcirculation has recently emerged from studies in COVID-19 decedents. The present study investigated the ultrastructure of coronary microthrombi in heart failure (HF) due to cardiomyopathies that are unrelated to COVID-19 infection. In addition, we have investigated the role of von Willebrand factor (VWF) and PECAM-1 in microthrombus formation. We used electron microscopy to investigate the occurrence of microthrombi in patients with HF due to dilated (DCM, n = 7), inflammatory (MYO, n = 6) and ischemic (ICM, n = 7) cardiomyopathy and 4 control patients. VWF and PECAM-1 was studied by quantitative immunohistochemistry and Western blot. In comparison to control, the number of microthrombi was increased 7–9 times in HF. This was associated with a 3.5-fold increase in the number of Weibel–Palade bodies (WPb) in DCM and MYO compared to control. A fivefold increase in WPb in ICM was significantly different from control, DCM and MYO. In Western blot, VWF was increased twofold in DCM and MYO, and more than threefold in ICM. The difference between ICM and DCM and MYO was statistically significant. These results were confirmed by quantitative immunohistochemistry. Compared to control, PECAM-1 was by approximatively threefold increased in all groups of patients. This is the first study to demonstrate the occurrence of microthrombi in the failing human heart. The occurrence of microthrombi is associated with increased expression of VWF and the number of WPb, being more pronounced in ICM. These changes are likely not compensated by increases in PECAM-1 expression.

Clusterin knockdown has effects on intracellular and secreted von Willebrand factor in human umbilical vein endothelial cells.

Alterations in von Willebrand factor (VWF) have an important role in human health and disease. Deficiency of VWF is associated with symptoms of bleeding and excesses of VWF are associated with thrombotic outcomes. Understanding the mechanisms that drive VWF regulation can lead to a better understanding of modulation of VWF levels in humans. We identified clusterin (CLU) as a potential candidate regulator of VWF based on a single cell RNA sequencing (scRNA-seq) analysis in control endothelial cells (ECs) and von Willebrand disease (VWD) endothelial colony-forming-cells (ECFCs). We found that patients with deficiencies of VWF (von Willebrand disease, VWD) had decreased CLU expression and ECs with low VWF expression also had low CLU expression. Based on these findings, we sought to evaluate the role of CLU in the regulation of VWF, specifically as it relates to VWD. As CLU is primarily thought to be a golgi protein involved in protein chaperoning, we hypothesized that knockdown of CLU would lead to decreases in VWF and alterations in Weibel-Palade bodies (WPBs). We used both siRNA- and CRISPR-Cas9-based approaches to modulate CLU in human umbilical vein endothelial cells (HUVECs) and evaluated VWF protein levels, VWF mRNA copy number, and WPB quantity and size. We demonstrated that siRNA-based knockdown of CLU resulted in decreases in VWF content in cellular lysates and supernatants, but no significant change in WPB quantity or size. A CRISPR-Cas9-based knockdown of CLU demonstrated similar findings of decreases in intracellular VWF content but no significant change in WPB quantity or size. Our data suggests that CLU knockdown is associated with decreases in cellular VWF content but does not affect VWF mRNA levels or WPB quantity or size.

Mechanism of astragaloside Ⅳ combined with Panax notoginseng saponins in regulating angiogenesis to treat cerebral ischemia based on network pharmacology and experimental verification

Network pharmacology and animal and cell experiments were employed to explore the mechanism of astragaloside Ⅳ(AST Ⅳ) combined with Panax notoginseng saponins(PNS) in regulating angiogenesis to treat cerebral ischemia. The method of network pharmacology was used to predict the possible mechanisms of AST Ⅳ and PNS in treating cerebral ischemia by mediating angiogenesis. In vivo experiment: SD rats were randomized into sham, model, and AST Ⅳ(10 mg·kg~(-1)) + PNS(25 mg·kg~(-1)) groups, and the model of cerebral ischemia was established with middle cerebral artery occlusion(MCAO) method. AST Ⅳ and PNS were administered by gavage twice a day. the Longa method was employed to measure the neurological deficits. The brain tissue was stained with hematoxylin-eosin(HE) to reveal the pathological damage. Immunohistochemical assay was employed to measure the expression of von Willebrand factor(vWF), and immunofluorescence assay to measure the expression of vascular endothelial growth factor A(VEGFA). Western blot was employed to determine the protein levels of vascular endothelial growth factor receptor 2(VEGFR2), VEGFA, phosphorylated phosphatidylinositol 3-kinase(p-PI3K), and phosphorylated protein kinase B(p-AKT) in the brain tissue. In vitro experiment: the primary generation of rat brain microvascular endothelial cells(rBEMCs) was cultured and identified. The third-generation rBMECs were assigned into control, model, AST Ⅳ(50 μmol·L~(-1)) + PNS(30 μmol·L~(-1)), LY294002(PI3K/AKT signaling pathway inhibitor), 740Y-P(PI3K/AKT signaling pathway agonist), AST Ⅳ + PNS + LY294002, and AST Ⅳ + PNS + 740Y-P groups. Oxygen glucose deprivation/re-oxygenation(OGD/R) was employed to establish the cell model of cerebral ischemia-reperfusion injury. The cell counting kit-8(CCK-8) and scratch assay were employed to examine the survival and migration of rBEMCs, respectively. Matrigel was used to evaluate the tube formation from rBEMCs. The Transwell assay was employed to examine endothelial cell permeability. Western blot was employed to determine the expression of VEGFR2, VEGFA, p-PI3K, and p-AKT in rBEMCs. The results of network pharmacology analysis showed that AST Ⅳ and PNS regulated 21 targets including VEGFA and AKT1 of angiogenesis in cerebral infarction. Most of these 21 targets were involved in the PI3K/AKT signaling pathway. The in vivo experiments showed that compared with the model group, AST Ⅳ + PNS reduced the neurological deficit score(P&lt;0.05) and the cell damage rate in the brain tissue(P&lt;0.05), promoted the expression of vWF and VEGFA(P&lt;0.01) and angiogenesis, and up-regulated the expression of proteins in the PI3K/AKT pathway(P&lt;0.05, P&lt;0.01). The in vitro experiments showed that compared with the model group, the AST Ⅳ + PNS, 740Y-P, AST Ⅳ + PNS + LY294002, and AST Ⅳ + PNS + 740Y-P improved the survival of rBEMCs after OGD/R, enhanced the migration of rBEMCs, increased the tubes formed by rBEMCs, up-regulated the expression of proteins in the PI3K/AKT pathway, and reduced endothelial cell permeability(P&lt;0.05, P&lt;0.01). Compared with the LY294002 group, the AST Ⅳ + PNS + LY294002 group showed increased survival rate, migration rate, and number of tubes, up-regulated expression of proteins in the PI3K/AKT pathway, and decreased endothelial cell permeability(P&lt;0.05,P&lt;0.01). Compared with the AST Ⅳ + PNS and 740Y-P groups, the AST Ⅳ + PNS + 740Y-P group presented increased survival rate, migration rate, and number of tubes and up-regulated expression of proteins in the PI3K/AKT pathway, and reduced endothelial cell permeability(P&lt;0.01). This study indicates that AST Ⅳ and PNS can promote angiogenesis after cerebral ischemia by activating the PI3K/AKT signaling pathway.

Abstract TMP112: Von Willebrand Factor (VWF) Modulates Smooth Muscle Cell Proliferation During the Outward Remodeling of Leptomeningeal Collateral Arterioles Following Stroke

Introduction: The leptomeningeal collaterals (LMCs) undergo outward remodeling after stroke to increase rescue flow toward the occluded region. We previously showed increased VWF in remodeled LMCs and others have shown that VWF can act as a smooth muscle cell (SMC) mitogen. Here we test the hypothesis that VWF modulates vascular remodeling of LMCs in the post-stroke brain. Methods: Permanent distal middle cerebral artery occlusion (pdMCAO) was performed in C57BL6 WT mice (cohort 1; 4 mos), aged (cohort 2; 24 mos) or VWF KO and WT male mice (cohort 3; 4 mos). At 3, 7, and 14 days after pdMCAO, the pial vessels were processed for VWF/Ki67/SMA immunofluorescence and morphometric analysis. Lastly, distribution of VWF was evaluated in LMCs from human and pig brains. Results: During the 3-14 days post-stroke, WT mice of cohort 1 demonstrated significantly increased VWF in ipsilateral LMCs as well as increased Ki67 positive cells. In ECs, Ki67-positive cells were 10.68 ± 1.48 and 10.73 ± 1.26 per mm of vessel at 3 and 7 days, respectively. In SMCs, Ki67-positive cells were 0.049 ± 0.22 and 4.546 ± 0.95 per mm vessel at 3 and 7 days, respectively. By 14 days, LMC no longer showed Ki67-positive ECs or SMCs. In aged cohort 2, along with attenuated VWF expression and remodeling, the Ki67-positive ECs and SMCs were significantly decreased in the aged mice compared to young mice (Ki67-positive ECs were reduced by 40% and 50% at 3 and 7 days, respectively; Ki67-positive SMCs were reduced by 75% at 7 days). In cohort 3, Ki67-positive SMCs were absent in the VWF-KOs at 3 days post-stroke. However, by 7 days, Ki67-positive SMCs were equivalent between WT and VWF-KOs (4.8-5.0 per mm vessel). Lastly, the presence of VWF was detected in the smooth muscle layer of LMCs of human and pig brains. Conclusions: Our study revealed increased VWF in the mural layer of remodeled LMCs and both EC and SMC proliferation. The remodeling response, VWF expression, and number of proliferative cells were attenuated in LMCs from aged brains. Knockout of VWF resulted in reduced LMC remodeling and delayed SMC proliferation. Our findings also provide evidence for VWF within the smooth muscle layer of pig and human brain arterioles, supporting the broader potential role of VWF as a molecular player in vascular remodeling.

Functional Assessment of VWD Type 2N Variants Using Mammalian Cell Displayed Surface-Tethered Von Willebrand Factor

Background von Willebrand factor (VWF) is a large plasma protein critical in hemostasis and thrombosis. Defects in VWF cause the inherited autosomal bleeding disorder von Willebrand disease (VWD). One critical function of VWF is to bind circulating coagulation factor VIII (FVIII) and protect it from rapid clearance. Type 2N VWD is a recessive form of VWD characterized by low FVIII levels due to impairment in VWF-FVIII binding. Type 2N VWD clinically is similar to mild-to-moderate hemophilia A, an X-linked bleeding disorder caused by deficiency in FVIII. It is critical to distinguish type 2N VWD from hemophilia A because the treatments are different. VWF genotyping can inform accurate diagnoses, treatment, and testing in relatives. With the rapid expansion of DNA sequencing, a growing number of DNA variants are being identified in the VWF gene. However, the interpretation of significance of these variants is often challenged by insufficient evidence to inform confident classification regarding pathogenicity. In vitro functional assays provide an avenue to develop the evidence needed to accurately assign functional significance to DNA variants. We adapted multiplexed surface tethering of extracellular proteins (MultiSTEP), our mammalian cell surface display system for secreted proteins, to display VWF and test the functional impact of VWF variants on VWF-FVIII binding. Methods We constructed a VWF cDNA of common VWF coding sequences by mutating rare variants to the more common nucleotides. The regions encoding the VWF propeptide were deleted (∆Pro-VWF). ∆Pro-VWF was cloned into our MultiSTEP cassette that provides a C-terminal flexible linker, Strep II tag, and CD28 transmembrane domain. Three VWF missense variants implicated in type 2N VWD (Table 1) that had varying levels of evidence to support classification of pathogenicity were chosen for study - VWF c.2561 G&amp;gt;A (p.R854Q), c.2572 T&amp;gt;A (p.C858S), and c.2635 G&amp;gt;A (p.D879N). Variants were subcloned into our ∆Pro-VWF cassette and then recombined into the genomically integrated MultiSTEP landing pad in HEK293 Freestyle cells. Following induction of expression, VWF-displaying cells were incubated with recombinant FVIII. VWF expression was measured using a polyclonal anti-VWF antibody, and VWF-FVIII binding was detected with two different monoclonal antibodies to FVIII. Cells were incubated with fluorescently-conjugated secondary antibodies and cell surface VWF and FVIII abundance determined by flow cytometry. Results We show that ∆Pro-VWF robustly displays in our MultiSTEP system and binds FVIII. All three VWF missense variants express VWF at levels similar to ∆Pro-VWF. Relative to ∆Pro-VWF all three variants show marked impairment in VWF-FVIII binding (Figure 1), providing strong in vitro evidence for pathogenicity in type 2N VWD useful in variant reinterpretation (bold column in Table 1). Conclusions We have developed an in vitro mammalian cell surface display system for the interrogation of VWF variants and adapted it to study VWF-FVIII binding. The Pathogenic variant p.R854Q shows decreased VWF-FVIII binding in this assay, as expected. The Likely Pathogenic variant p.D879N and the Variant of Uncertain Significance p.C858S both exhibit a profound loss of VWF-FVIII binding in this assay. Our results provide evidence for reclassification of p.C858S to Likely Pathogenic for type 2N VWD. We expect our system can be used at scale to similarly interrogate the functional significance of a multiplexed library of VWF variants and improve variant interpretation in VWD.

Comprehensive bioinformatics analysis of the role of VWF in the tumor microenvironment of malignant mesothelioma.

To explore the influence and effect of tumor microenvironment on the development of malignant mesothelioma using machine learning methods. 87 open cases were downloaded from the Cancer Genome Atlas database including transcriptome data, clinical data, and mutation data. The immune, stromal, and estimate scores were calculated for each case by using the ESTIMATE algorithm, and then the cases were grouped according to high and low stromal scores to predict all-cause survival in malignant mesothelioma cases. Their mutation data were analyzed to reveal the differences in mutated genes between the 2 groups, and then the von Willebrand factor (VWF) and FCRL3 genes were identified according to the intersection of DEGs and high-frequency mutated genes. Lastly, the correlation between VWF and the immune checkpoint of 22 kinds of immune cells was analyzed by using the CIBERSORT package of R software. A significant difference was found in the survival time of patients between the high and low stromal score groups. High expression of the VWF gene was negatively correlated with the prognosis of malignant mesothelioma, and the expression of VWF was positively correlated with naive B cells and activated CD4 memory T cells and negatively correlated with NK cells. The results revealed that high expression of VWF may involve in the development of malignant mesothelioma, and the anti-CTLA4 immune checkpoint treatment may have certain efficacy.

OC 13.2 Improved Maturation of Human Pluripotent Stem Cell-Derived Endothelial Cells to Study Von Willebrand Factor Expression and Function

OC 13.2 Improved Maturation of Human Pluripotent Stem Cell-Derived Endothelial Cells to Study Von Willebrand Factor Expression and Function

Aging Is Associated With Organ-Specific Alterations in the Level and Expression Pattern of von Willebrand Factor.

VWF (von Willebrand factor) is an endothelial-specific procoagulant protein with a major role in thrombosis. Aging is associated with increased circulating levels of VWF, which presents a risk factor for thrombus formation. Circulating plasma, cellular protein, and mRNA levels of VWF were determined and compared in young and aged mice. Major organs were subjected to immunofluorescence analyses to determine the vascular pattern of VWF expression and the presence of platelet aggregates. An in vitro model of aging, using extended culture time of endothelial cells, was used to explore the mechanism of age-associated increased VWF levels. Increased circulating plasma levels of VWF with elevated levels of larger multimers, indicative of VWF functional activity, were observed in aged mice. VWF mRNA and cellular protein levels were significantly increased in the brains, lungs, and livers but not in the kidneys and hearts of aged mice. Higher proportion of small vessels in brains, lungs, and livers of aged mice exhibited VWF expression compared with young, and this was concomitant with increased platelet aggregate formation. Prolonged culture of endothelial cells resulted in increased cell senescence that correlated with increased VWF expression; VWF expression was specifically detected in senescent cultured endothelial cells and abolished in response to p53 knockdown. A significantly higher proportion of VWF expressing endothelial cells in vivo exhibited senescence markers SA-β-Gal (senescence-associated β-galactosidase) and p53 in aged mouse brains compared with that of the young. Aging elicits a heterogenic response in endothelial cells with regard to VWF expression, leading to organ-specific increase in VWF levels and alterations in vascular tree pattern of expression. This is concomitant with increased platelet aggregate formation. The age-associated increase in VWF expression may be modulated through the process of cell senescence, and p53 transcription factor contributes to its regulation.