CD248 enhances tissue factor procoagulant function, promoting arterial and venous thrombosis in mouse models

High plasma levels of endosialin and cardiovascular events in patients undergoing coronary angiography

Endosialin, also known as tumor endothelial marker-1, is a transmembrane glycoprotein that plays a role in inflammation and tumor progression. Endosialin is upregulated in atherosclerotic lesions. To elucidate the association between blood endosialin levels and cardiovascular events, we measured plasma endosialin levels in 389 patients undergoing coronary angiography who were followed up for a mean follow-up of 6.4 ± 4.2 years for cardiovascular events (cardiovascular death, myocardial infarction, unstable angina, heart failure, stroke, or need for coronary revascularization). Of the 389 patients, 223 had coronary artery disease (CAD). No significant difference was found in plasma endosialin levels between patients with and without CAD (median 0.92 vs. 0.92 ng/mL). During the follow-up, cardiovascular events occurred in 62 patients. Compared with patients without events, those with events had higher endosialin levels (1.12 vs. 0.89 ng/mL), and more often had endosialin level of > 1.1 ng/mL (53% vs. 31%) (P < 0.01). A Kaplan-Meier analysis showed lower event-free survival in patients with endosialin > 1.1 ng/mL than those with ≤ 1.1 ng/mL (P < 0.01). In a multivariate Cox regression analysis, endosialin > 1.1 ng/mL was an independent predictor of cardiovascular events (hazard ratio = 2.00; 95%CI = 1.21-3.32; P < 0.01). Thus, high plasma endosialin levels were associated with an increased risk of cardiovascular events in patients undergoing coronary angiography.

CD248 promotes insulin resistance by binding to the insulin receptor and dampening its insulin-induced autophosphorylation

BACKGROUND

In spite of new treatments, the incidence of type 2 diabetes (T2D) and its morbidities continue to rise. The key feature of T2D is resistance of adipose tissue and other organs to insulin. Approaches to overcome insulin resistance are limited due to a poor understanding of the mechanisms and inaccessibility of drugs to relevant intracellular targets. We previously showed in mice and humans that CD248, a pre/adipocyte cell surface glycoprotein, acts as an adipose tissue sensor that mediates the transition from healthy to unhealthy adipose, thus promoting insulin resistance.

METHODS

Molecular mechanisms by which CD248 regulates insulin signaling were explored using in vivo insulin clamp studies and biochemical analyses of cells/tissues from CD248 knockout (KO) and wild-type (WT) mice with diet-induced insulin resistance. Findings were validated with human adipose tissue specimens.

FINDINGS

Genetic deletion of CD248 in mice, overcame diet-induced insulin resistance with improvements in glucose uptake and lipolysis in white adipose tissue depots, effects paralleled by increased adipose/adipocyte GLUT4, phosphorylated AKT and GSK3β, and reduced ATGL. The insulin resistance of the WT mice could be attributed to direct interaction of the extracellular domains of CD248 and the insulin receptor (IR), with CD248 acting to block insulin binding to the IR. This resulted in dampened insulin-mediated autophosphorylation of the IR, with reduced downstream signaling/activation of intracellular events necessary for glucose and lipid homeostasis.

INTERPRETATION

Our discovery of a cell-surface CD248-IR complex that is accessible to pharmacologic intervention, opens research avenues toward development of new agents to prevent/reverse insulin resistance.

FUNDING

Funded by Canadian Institutes of Health Research (CIHR), Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundations for Innovation (CFI), the Swedish Diabetes Foundation, Family Ernfors Foundation and Novo Nordisk Foundation.

Rehabilitation nursing after lower limb fracture: Preventing deep vein thrombosis and enhancing quality of life

This study aimed to assess the preventive role of rehabilitation nursing in the formation of deep vein thrombosis (DVT) in the lower limbs after fracture and its effect on the patient's quality of life. Ninety patients with lower limb fractures were randomly divided into a study group (n = 45) and a control group (n = 45). Patients in the control group received routine care postoperatively, whereas patients in the study group received rehabilitation nursing intervention on the same postoperative day. A follow-up examination was conducted after 3 months. The occurrence rate of lower limb DVT (LDVT) complications, hemorheology, quality of life (SF-36) scores, coagulation profile, and nursing satisfaction were compared between the groups. After the intervention, the study group presented with lower extremity DVT and higher hemorheology indices than those of the control group (P < .05). The SF-36 scores of both groups increased, but the increase in SF-36 scores in the study group was more significant (P < .001). The satisfaction level of the patients in the study group with nursing services was higher than that of the control group (P = .004). Coagulation indicators can be effectively adjusted and the occurrence of postoperative complications can be reduced in patients undergoing spine fracture surgery such as DVT via standardized rehabilitation care, thereby improving patients' quality of life and nursing conditions.

Integrin β Expression as a New Diagnostic Marker for Arteriovenous Thrombosis: A Single-Center Prospective Study

Integrin β plays an important role in the pathogenesis of thrombosis and inflammation, and it may be a shared pathogenic mechanism between arterial and venous thromboses. With the goal of identifying new treatment targets for thrombotic diseases and specific diagnostic markers for venous thromboembolism (VTE), this prospective clinical study was performed to clarify the relationship between integrin and thrombosis. The levels of integrin β1-3, interleukin-6 (IL-6), and C-reactive protein were significantly higher in patients with acute myocardial infarction (AMI; n = 44) and acute VTE (n = 43) compared to healthy controls (n = 33). The IL-6 and integrin β1-3 levels were also significantly higher in the AMI group compared to the VTE and control groups. Logistic regression analysis identified IL-6 and integrin β1-3 levels as independent risk factors for thrombotic disease. Based on the receiver-operating characteristic curve, Youden index, sensitivity, and specificity, the diagnostic accuracy value for VTE was greater than 0.8 when integrins β1, β2, and β3 were combined. Overall, these results suggest that integrin β levels can contribute to improving the diagnosis and treatment of arteriovenous thrombosis.

Monocyte Tissue Factor Expression: Lipopolysaccharide Induction and Roles in Pathological Activation of Coagulation

The coagulation system is a part of the mammalian host defense system. Pathogens and pathogen components, such as bacterial lipopolysaccharide (LPS), induce tissue factor (TF) expression in circulating monocytes that then activates the coagulation protease cascade. Formation of a clot limits dissemination of pathogens, enhances the recruitment of immune cells, and facilitates killing of pathogens. However, excessive activation of coagulation can lead to thrombosis. Here, we review studies on the mechanism of LPS induction of TF expression in monocytes and its contribution to thrombosis and disseminated intravascular coagulation. Binding of LPS to Toll-like receptor 4 on monocytes induces a transient expression of TF that involves activation of intracellular signaling pathways and binding of various transcription factors, such as c-rel/p65 and c-Fos/c-Jun, to the TF promoter. Inhibition of TF in endotoxemia and sepsis models reduces activation of coagulation and improves survival. Studies with endotoxemic mice showed that hematopoietic cells and myeloid cells play major roles in the activation of coagulation. Monocyte TF expression is also increased after surgery. Activated monocytes release TF-positive extracellular vesicles (EVs) and levels of circulating TF-positive EVs are increased in endotoxemic mice and in patients with sepsis. More recently, it was shown that inflammasomes contribute to the induction of TF expression and activation of coagulation in endotoxemic mice. Taken together, these studies indicate that monocyte TF plays a major role in activation of coagulation. Selective inhibition of monocyte TF expression may reduce pathologic activation of coagulation in sepsis and other diseases without affecting hemostasis.

Tissue factor in cancer-associated thromboembolism: possible mechanisms and clinical applications

Venous and arterial thromboses, called as cancer-associated thromboembolism (CAT), are common complications in cancer patients that are associated with high mortality. The cell-surface glycoprotein tissue factor (TF) initiates the extrinsic blood coagulation cascade. TF is overexpressed in cancer cells and is a component of extracellular vesicles (EVs). Shedding of TF⁺EVs from cancer cells followed by association with coagulation factor VII (fVII) can trigger the blood coagulation cascade, followed by cancer-associated venous thromboembolism in some cancer types. Secretion of TF is controlled by multiple mechanisms of TF⁺EV biogenesis. The procoagulant function of TF is regulated via its conformational change. Thus, multiple steps participate in the elevation of plasma procoagulant activity. Whether cancer cell-derived TF is maximally active in the blood is unclear. Numerous mechanisms other than TF⁺EVs have been proposed as possible causes of CAT. In this review, we focused on a wide variety of regulatory and shedding mechanisms for TF, including the effect of SARS-CoV-2, to provide a broad overview for its role in CAT. Furthermore, we present the current technical issues in studying the relationship between CAT and TF.