The Gab2-MALT1 axis regulates thromboinflammation and deep vein thrombosis

Interactions between integrin α9β1 and VCAM-1 promote neutrophil hyperactivation and mediate poststroke DVT

ABSTRACT

Venous thromboembolic events are significant contributors to morbidity and mortality in patients with stroke. Neutrophils are among the first cells in the blood to respond to stroke and are known to promote deep vein thrombosis (DVT). Integrin α9 is a transmembrane glycoprotein highly expressed on neutrophils and stabilizes neutrophil adhesion to activated endothelium via vascular cell adhesion molecule 1 (VCAM-1). Nevertheless, the causative role of neutrophil integrin α9 in poststroke DVT remains unknown. Here, we found higher neutrophil integrin α9 and plasma VCAM-1 levels in humans and mice with stroke. Using mice with embolic stroke, we observed enhanced DVT severity in a novel model of poststroke DVT. Neutrophil-specific integrin α9-deficient mice (α9fl/flMrp8Cre+/-) exhibited a significant reduction in poststroke DVT severity along with decreased neutrophils and citrullinated histone H3 in thrombi. Unbiased transcriptomics indicated that α9/VCAM-1 interactions induced pathways related to neutrophil inflammation, exocytosis, NF-κB signaling, and chemotaxis. Mechanistic studies revealed that integrin α9/VCAM-1 interactions mediate neutrophil adhesion at the venous shear rate, promote neutrophil hyperactivation, increase phosphorylation of extracellular signal-regulated kinase, and induce endothelial cell apoptosis. Using pharmacogenomic profiling, virtual screening, and in vitro assays, we identified macitentan as a potent inhibitor of integrin α9/VCAM-1 interactions and neutrophil adhesion to activated endothelial cells. Macitentan reduced DVT severity in control mice with and without stroke, but not in α9fl/flMrp8Cre+/- mice, suggesting that macitentan improves DVT outcomes by inhibiting neutrophil integrin α9. Collectively, we uncovered a previously unrecognized and critical pathway involving the α9/VCAM-1 axis in neutrophil hyperactivation and DVT.

Circulating Cytokines and Venous Thromboembolism: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

 Epidemiological evidence has linked circulating cytokines to venous thromboembolism (VTE). However, it remains uncertain whether these associations are causal due to confounding factors or reverse causality. We aim to explore the causality between circulating cytokines and VTE, encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE).

METHODS

 In the current bidirectional Mendelian randomization (MR) study, instrumental variables of 41 circulating cytokines were obtained from the genome-wide association study meta-analyses (8,293 individuals). Summary statistics for the association of VTE (17,048 cases and 325,451 controls), DVT (8,077 cases and 295,014 controls), and PE (8,170 cases and 333,487 controls) were extracted from the FinnGen Study. A multivariable MR study was conducted to adjust for potential confounders. The inverse-variance weighted method was employed as the main analysis, and comprehensive sensitivity analyses were conducted in the supplementary analyses.

RESULTS

 The MR analysis indicated stromal cell-derived factor-1α was suggestively associated with a reduced risk of VTE (odds ratio [OR]: 0.90; 95% confidence interval [CI]: 0.81-0.99; p = 0.033) and DVT (OR: 0.85; 95% CI: 0.75-0.97; p = 0.015). In addition, suggestive association of granulocyte colony-stimulating factor with PE (OR: 1.20; 95% CI: 1.06-1.37; p = 0.005) was observed. Multivariable MR analysis showed that the effect of cytokines on VTE was partly mediated through hemoglobin A1c and systolic blood pressure. Reverse MR analysis revealed that VTE was linked to decreased levels of several cytokines.

CONCLUSION

 We provide suggestive genetic evidence supporting the bidirectional causal effect between circulating cytokines and VTE, highlighting the importance of targeting circulating cytokines to reduce the incidence of VTE.

Coagulation Protease-Driven Cancer Immune Evasion: Potential Targets for Cancer Immunotherapy

Blood coagulation and cancer are intrinsically connected, hypercoagulation-associated thrombotic complications are commonly observed in certain types of cancer, often leading to decreased survival in cancer patients. Apart from the common role in coagulation, coagulation proteases often trigger intracellular signaling in various cancers via the activation of a G protein-coupled receptor superfamily protease: protease-activated receptors (PARs). Although the role of PARs is well-established in the development and progression of certain types of cancer, their impact on cancer immune response is only just emerging. The present review highlights how coagulation protease-driven PAR signaling plays a key role in modulating innate and adaptive immune responses. This is followed by a detailed discussion on the contribution of coagulation protease-induced signaling in cancer immune evasion, thereby supporting the growth and development of certain tumors. A special section of the review demonstrates the role of coagulation proteases, thrombin, factor VIIa, and factor Xa in cancer immune evasion. Targeting coagulation protease-induced signaling might be a potential therapeutic strategy to boost the immune surveillance mechanism of a host fighting against cancer, thereby augmenting the clinical consequences of targeted immunotherapeutic regimens.

Inhibition of the MALT1-LPCAT3 axis protects cartilage degeneration and osteoarthritis

The proinflammatory cytokines and arachidonic acid (AA)-derived eicosanoids play a key role in cartilage degeneration in osteoarthritis (OA). The lysophosphatidylcholine acyltransferase 3 (LPCAT3) preferentially incorporates AA into the membranes. Our recent studies showed that MALT1 [mucosa-associated lymphoid tissue lymphoma translocation protein 1]) plays a crucial role in propagating inflammatory signaling triggered by IL-1β and other inflammatory mediators in endothelial cells. The present study shows that LPCAT3 expression was up-regulated in both human and mice articular cartilage of OA, and correlated with severity of OA. The IL-1β-induces cell death via upregulation of LPCAT3, MMP3, ADAMTS5, and eicosanoids via MALT1. Gene silencing or pharmacological inhibition of LPCAT3 or MALT1 in chondrocytes and human cartilage explants notably suppressed the IL-1β-induced cartilage catabolism through inhibition of expression of MMP3, ADAMTS5, and also secretion of cytokines and eicosanoids. Mechanistically, overexpression of MALT1 in chondrocytes significantly upregulated the expression of LPCAT3 along with MMP3 and ADAMTS5 via c-Myc. Inhibition of c-Myc suppressed the IL-1β-MALT1-dependent upregulation of LPCAT3, MMP3 and ADAMTS5. Consistent with the in vitro data, pharmacological inhibition of MALT1 or gene silencing of LPCAT3 using siRNA-lipid nanoparticles suppressed the synovial articular cartilage erosion, pro-inflammatory cytokines, and eicosanoids such as PGE2, LTB4, and attenuated osteoarthritis induced by the destabilization of the medial meniscus in mice. Overall, our data reveal a previously unrecognized role of the MALT1-LPCAT3 axis in osteoarthritis. Targeting the MALT1-LPCAT3 pathway with MALT1 inhibitors or siRNA-liposomes of LPCAT3 may become an effective strategy to treat OA by suppressing eicosanoids, matrix-degrading enzymes, and proinflammatory cytokines.

Nanomicrosphere sustained-release urokinase systems with antioxidant properties for deep vein thrombosis therapy

Deep vein thrombosis (DVT) is a venous return disorder caused by abnormal clotting of blood in deep veins. After thrombosis, most of the thrombus will spread to the deep vein trunk throughout the limb. If DVT is not treated in time, most of them will develop into thrombosis sequelae and even threaten life. Intravenous thrombolytic drugs are the most promising strategy for treating DVT, but current drugs used for thrombolysis suffer from short half-lives and narrow therapeutic indexes. To effectively manage DVT, it is necessary to develop a novel multifunctional drug-loading system to effectively prolong the treatment time and improve the therapeutic efficacy. In this study, a urokinase-loaded protocatechuic aldehyde-modified chitosan microsphere drug-loading platform was constructed for the treatment of DVT. This microsphere adsorbed urokinase well through electrostatic interaction, and the introduction of bovine serum albumin conferred stability to the microspheres. Therefore, the microsphere drug delivery system could achieve slow drug release to effectively dissolve blood fibrin. In addition, chitosan grafted with protocatechuic aldehyde imparted excellent antioxidant activity to the system to reduce free radicals in the blood vessels. Effective management of oxidative stress could avoid abnormal platelet activation and new thrombus formation. The experimental results showed that this microsphere had good biocompatibility, anti-inflammatory properties, and considerable thrombolytic activity. In conclusion, this study provided a new direction and developed a novel multi-functional nano microsphere drug delivery platform for the treatment of DVT.

MALT1 Positively Relates to T Helper 1 and T Helper 17 cells, and Serves as a Potential Biomarker for Predicting 30-Day Mortality in Stanford Type A Aortic Dissection Patients

Mucosa-associated lymphoid tissue 1 (MALT1) regulates inflammation and T helper (Th) cell differentiation, which may participate in the progression of Stanford type A aortic dissection (TAAD). This study intended to assess the association of MALT1 expression with prognosis in TAAD patients. In this prospective study, MALT1 expression was measured by reverse transcription-quantitative polymerase chain reaction assay from peripheral blood samples in 100 TAAD patients and 100 non-AD controls (non-AD patients with chest pain) before treatment. Besides, Th1, Th2, and Th17 cells of TAAD patients before treatment were measured by flow cytometry assay, and their 30-day mortality was recorded. MALT1 expression was ascended in TAAD patients vs. non-AD controls (P < 0.001). In TAAD patients, elevated MALT1 expression was linked with hypertension complication (P = 0.009), increased systolic blood pressure (r = 0.291, P = 0.003), C-reactive protein (CRP) (r = 0.286, P = 0.004), and D-dimer (r = 0.359, P < 0.001). Additionally, MALT1 expression was positively correlated with Th1 cells (r = 0.312, P = 0.002) and Th17 cells (r = 0.397, P < 0.001), but not linked with Th2 cells (r = -0.166, P = 0.098). Notably, the 30-day mortality of TAAD patients was 28.0%. MALT1 expression [odds ratio (OR) = 1.936, P = 0.004], CRP (OR = 1.108, P = 0.002), D-dimer (OR = 1.094, P = 0.003), and surgery timing (emergency vs. selective) (OR = 8.721, P = 0.024) independently predicted increased risk of death within 30 days in TAAD patients. Furthermore, the combination of the above-mentioned independent factors had an excellent ability in predicting 30-day mortality with the area under curve of 0.949 (95% confidence interval: 0.909-0.989). MALT1 expression relates to increased Th1 cells, Th17 cells, and 30-day mortality risk in TAAD patients.

Recent Advances on the Molecular Mechanism and Clinical Trials of Venous Thromboembolism

Venous thromboembolism is a condition that includes deep vein thrombosis and pulmonary embolism. It is the third most common cardiovascular disease behind acute coronary heart disease and stroke. Over the past few years, growing research suggests that venous thrombosis is also related to the immune system and inflammatory factors have been confirmed to be involved in venous thrombosis. The role of inflammation and inflammation-related biomarkers in cerebrovascular thrombotic disease is the subject of ongoing debate. P-selectin leads to platelet-monocyte aggregation and stimulates vascular inflammation and thrombosis. The dysregulation of miRNAs has also been reported in venous thrombosis, suggesting the involvement of miRNAs in the progression of venous thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is a crucial component of the plasminogen-plasmin system, and elevated levels of PAI-1 in conjunction with advanced age are significant risk factors for thrombosis. In addition, it has been showed that one of the ways that neutrophils promote venous thrombosis is the formation of neutrophil extracellular traps (NETs). In recent years, the role of extracellular vesicles (EVs) in the occurrence and development of VTE has been continuously revealed. With the advancement of research technology, the complex regulatory role of EVs on the coagulation process has been gradually discovered. However, our understanding of the causes and consequences of these changes in venous thrombosis is still limited. Therefore, we review our current understanding the molecular mechanisms of venous thrombosis and the related clinical trials, which is crucial for the future treatment of venous thrombosis.

E3 Ubiquitin Ligases in Endothelial Dysfunction and Vascular Diseases: Roles and Potential Therapies

ABSTRACT

Ubiquitin E3 ligases are a structurally conserved family of enzymes that exert a variety of regulatory functions in immunity, cell death, and tumorigenesis through the ubiquitination of target proteins. Emerging evidence has shown that E3 ubiquitin ligases play crucial roles in the pathogenesis of endothelial dysfunction and related vascular diseases. Here, we reviewed the new findings of E3 ubiquitin ligases in regulating endothelial dysfunction, including endothelial junctions and vascular integrity, endothelial activation, and endothelial apoptosis. The critical role and potential mechanism of E3 ubiquitin ligases in vascular diseases, such as atherosclerosis, diabetes, hypertension, pulmonary hypertension, and acute lung injury, were summarized. Finally, the clinical significance and potential therapeutic strategies associated with the regulation of E3 ubiquitin ligases were also proposed.

Beyond Macromolecules: Extracellular Vesicles as Regulators of Inflammatory Diseases

Inflammation is the defense mechanism of the immune system against harmful stimuli such as pathogens, toxic compounds, damaged cells, radiation, etc., and is characterized by tissue redness, swelling, heat generation, pain, and loss of tissue functions. Inflammation is essential in the recruitment of immune cells at the site of infection, which not only aids in the elimination of the cause, but also initiates the healing process. However, prolonged inflammation often brings about several chronic inflammatory disorders; hence, a balance between the pro- and anti-inflammatory responses is essential in order to eliminate the cause while producing the least damage to the host. A growing body of evidence indicates that extracellular vesicles (EVs) play a major role in cell-cell communication via the transfer of bioactive molecules in the form of proteins, lipids, DNA, RNAs, miRNAs, etc., between the cells. The present review provides a brief classification of the EVs followed by a detailed description of how EVs contribute to the pathogenesis of various inflammation-associated diseases and their implications as a therapeutic measure. The latter part of the review also highlights how EVs act as a bridging entity in blood coagulation disorders and associated inflammation. The findings illustrated in the present review may open a new therapeutic window to target EV-associated inflammatory responses, thereby minimizing the negative outcomes.

Vascular Inflammatory Diseases and Endothelial Phenotypes

The physiological functions of endothelial cells control vascular tone, permeability, inflammation, and angiogenesis, which significantly help to maintain a healthy vascular system. Several cardiovascular diseases are characterized by endothelial cell activation or dysfunction triggered by external stimuli such as disturbed flow, hypoxia, growth factors, and cytokines in response to high levels of low-density lipoprotein and cholesterol, hypertension, diabetes, aging, drugs, and smoking. Increasing evidence suggests that uncontrolled proinflammatory signaling and further alteration in endothelial cell phenotypes such as barrier disruption, increased permeability, endothelial to mesenchymal transition (EndMT), and metabolic reprogramming further induce vascular diseases, and multiple studies are focusing on finding the pathways and mechanisms involved in it. This review highlights the main proinflammatory stimuli and their effects on endothelial cell function. In order to provide a rational direction for future research, we also compiled the most recent data regarding the impact of endothelial cell dysfunction on vascular diseases and potential targets that impede the pathogenic process.

LncRNA NEAT1 Promotes Vascular Endothelial Cell Dysfunction via miR-218-5p/GAB2 and Serves as a Diagnostic Biomarker for Deep Vein Thrombosis

OBJECTIVE

Deep vein thrombosis (DVT) is a common peripheral disease. This study aimed to elucidate the diagnostic biomarker of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) in the DVT, and explore possible mechanisms in Human umbilical vein endothelial cells (HUVECs).

METHODS

101 patients with lower extremity DVT and 82 healthy controls were enrolled. RT-qPCR was designed to resolve the mRNA levels of NEAT1, miR-218-5p, and GAB2. ROC was applied for the diagnosis of DVT. Systemic inflammation (IL-1β, IL-6, and TNF-α) and adhesion factor (SELP, VCAM-1, and ICAM-1) were examined by the ELISA. And cell proliferation, migration, and apoptosis were conducted by the CCK-8, Transwell, flow cytometry assay. The targeting relationship was validated by Dual luciferase reporter and RIP analysis.

RESULTS

NEAT1 and GAB2 were upregulated in patients with DVT, while miR-218-5p was decreased (P < .01). Serum NEAT1 can identify DVT patients from healthy individuals. NEAT1 was positively correalted with fibrinolysis factors, coagulation factors, and vasoconstrictors. NEAT1 inhibited the proliferation, migration, and promoted apoptosis as well as inflammation and adhesion factors secretion of HUVECs (P < .05), but all were impaired by overexpression of miR-218-5p (P < .05). NEAT1 promoted GAB2 expression in DVT by acting as a sponge for miR-218-5p.

CONCLUSION

Elevated NEAT1 is a possible DVT diagnostic biomarker, and is implicated in vascular endothelial cell dysfunction via miR-218-5p/GAB2 axis.