Targeting Neutrophil α9 Improves Functional Outcomes After Stroke in Mice With Obesity-Induced Hyperglycemia.

Background: Obesity-induced hyperglycemia is a significant risk factor for stroke. Integrin α9β1 is expressed on neutrophils and stabilizes adhesion to the endothelium via ligands, including Fn-EDA (fibronectin containing extra domain A) and tenascin C. Although myeloid deletion of α9 reduces susceptibility to ischemic stroke, it is unclear whether this is mediated by neutrophil-derived α9.

Myeloid Cell PKM2 Deletion Enhances Efferocytosis and Reduces Atherosclerosis.

Background: The glycolytic enzyme PKM2 (pyruvate kinase muscle 2) is upregulated in monocytes/macrophages of patients with atherosclerotic coronary artery disease. However, the role of cell type-specific PKM2 in the setting of atherosclerosis remains to be defined. We determined whether myeloid cell-specific PKM2 regulates efferocytosis and atherosclerosis.

PKM2 promotes neutrophil activation and cerebral thromboinflammation: therapeutic implications for ischemic stroke.

There is a critical need for cerebro-protective interventions to improve the suboptimal outcomes of patients with ischemic stroke who have been treated with reperfusion strategies. We found that nuclear pyruvate kinase muscle 2 (PKM2), a modulator of systemic inflammation, was upregulated in neutrophils after the onset of ischemic stroke in both humans and mice. Therefore, we determined the role of PKM2 in stroke pathogenesis by using murine models with preexisting comorbidities.

Integrin α9 regulates smooth muscle cell phenotype switching and vascular remodeling.

Excessive proliferation of vascular smooth muscle cells (SMCs) remains a significant cause of in-stent restenosis. Integrins, which are heterodimeric transmembrane receptors, play a crucial role in SMC biology by binding to the extracellular matrix protein with the actin cytoskeleton within the SMC. Integrin α9 plays an important role in cell motility and autoimmune diseases; however, its role in SMC biology and remodeling remains unclear.

Smooth Muscle Cell-Specific PKM2 (Pyruvate Kinase Muscle 2) Promotes Smooth Muscle Cell Phenotypic Switching and Neointimal Hyperplasia.

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Cellular fibronectin promotes deep vein thrombosis in diet-induced obese mice.

Background: Overweight and obesity are significant risk factors for deep vein thrombosis (DVT). Cellular fibronectin containing extra domain A (Fn-EDA), an endogenous ligand for toll-like-receptor 4 (TLR4), contributes to thrombo-inflammation. The role of Fn-EDA in the modulation of DVT is not elucidated yet.

Differential Roles of Endothelial Cell-Derived and Smooth Muscle Cell-Derived Fibronectin Containing Extra Domain A in Early and Late Atherosclerosis.

Objective: The extracellular matrix of atherosclerotic arteries contains abundant deposits of cellular Fn-EDA (fibronectin containing extra domain A), suggesting a functional role in the pathophysiology of atherosclerosis. Fn-EDA is synthesized by several cell types, including endothelial cells (ECs) and smooth muscle cells (SMCs), which are known to contribute to different stages of atherosclerosis. Although previous studies using global Fn-EDA-deficient mice have demonstrated that Fn-EDA is proatherogenic, the cell-specific role of EC versus SMC-derived-Fn-EDA in atherosclerosis has not been investigated yet.

Targeting Myeloid-Specific Integrin α9β1 Improves Short- and Long-Term Stroke Outcomes in Murine Models With Preexisting Comorbidities by Limiting Thrombosis and Inflammation.

Rationale: Currently, there is no effective intervention available that can reduce brain damage following reperfusion. Clinical studies suggest a positive correlation between the increased influx of neutrophils and severity of brain injury following reperfusion. Integrin α9β1 is highly expressed on activated neutrophils and contributes to stable adhesion, but its role in stroke outcome has not been demonstrated to date.

Smooth muscle cell-specific fibronectin-EDA mediates phenotypic switching and neointimal hyperplasia.

Fibronectin-splice variant containing extra domain A (Fn-EDA) is associated with smooth muscle cells (SMCs) following vascular injury. The role of SMC-derived Fn-EDA in SMC phenotypic switching or its implication in neointimal hyperplasia remains unclear. Herein, using human coronary artery sections with a bare metal stent, we demonstrate the expression of Fn-EDA in the vicinity of SMC-rich neointima and peri-strut areas.

Fn-EDA (Fibronectin Containing Extra Domain A) in the Plasma, but Not Endothelial Cells, Exacerbates Stroke Outcome by Promoting Thrombo-Inflammation.

Background and Purpose- Cellular Fn-EDA (fibronectin containing extra domain A) is expressed in activated endothelial cells and elevated in circulation in patients with cardiovascular diseases. Although global deficiency of Fn-EDA in mice improves stroke outcome, the specific contribution of plasma versus endothelium Fn-EDA in stroke outcome is currently unknown. We investigated the role of plasma versus endothelial Fn-EDA in stroke exacerbation in the comorbid condition of hyperlipidemia.

Deletion of Extra Domain A of Fibronectin Reduces Acute Myocardial Ischaemia/Reperfusion Injury in Hyperlipidaemic Mice by Limiting Thrombo-Inflammation.

Background:  Fibronectin splicing variant containing extra domain A (Fn-EDA), which is an endogenous ligand for Toll-like receptor 4 (TLR4), is present in negligible amounts in the plasma of healthy humans, but markedly elevated in patients with co-morbid conditions including diabetes and hyperlipidaemia, which are risk factors for myocardial infarction (MI). Very little is known about the role of Fn-EDA in the pathophysiology of acute MI under these co-morbid conditions.

Materials And Methods:  We determined the role of Fn-EDA in myocardial ischaemia/reperfusion (I/R) injury in the hyperlipidaemic apolipoprotein E-deficient (ApoE) mice.

Nutrition and Nutraceuticals in Neuroinflammatory and Brain Metabolic Stress: Implications for Neurodegenerative Disorders.

Background And Objective: A steep rise in the incidences of neurodegenerative disorders could be the combined effect of several non-genetic factors such as increased life expectancy, environmental pollutants, lifestyle, and dietary habits, as population-level genetic change require multiple generations. Emerging evidence suggests that chronic over-nutrition induces brain metabolic stress and neuroinflammation, and are individually known to promote neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Although the association of metabolic disorders such as diabetes, hypertension, dyslipidemia, and atherosclerosis with the dietary habits is well known, neuronal implications of diet and nutritional factors is still in its infancy.

Endothelial Cell-Derived Von Willebrand Factor, But Not Platelet-Derived, Promotes Atherosclerosis in Apolipoprotein E-Deficient Mice.

Objective: VWF (von Willebrand factor) is synthesized by endothelial cells and megakaryocytes and is known to contribute to atherosclerosis. In vitro studies suggest that platelet-derived VWF (Plt-VWF) is biochemically and functionally different from endothelial cell-derived VWF (EC-VWF). We determined the role of different pools of VWF in the pathophysiology of atherosclerosis.

Fibronectin Containing Extra Domain A Induces Plaque Destabilization in the Innominate Artery of Aged Apolipoprotein E-Deficient Mice.

Objective: Fibronectin containing extra domain A (Fn-EDA) is an endogenous ligand of TLR4 (toll-like receptor 4) and is abundant in the extracellular matrix of advanced atherosclerotic lesions in human and mice. Irrespective of sex, deletion of Fn-EDA reduces early atherosclerosis in apolipoprotein E-deficient (Apoe) mice. However, the contribution of Fn-EDA in advanced atherosclerosis remains poorly characterized.

ADAMTS13 Retards Progression of Diabetic Nephropathy by Inhibiting Intrarenal Thrombosis in Mice.

Objective: ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I repeats-13) prevents microvascular thrombosis by cleaving prothrombogenic ultralarge von Willebrand factor (VWF) multimers. Clinical studies have found association between reduced ADAMTS13-specific activity, ultralarge VWF multimers, and thrombotic angiopathy in patients with diabetic nephropathy. It remains unknown, however, whether ADAMTS13 deficiency or ultralarge VWF multimers have a causative effect in diabetic nephropathy.

Endothelial Cell-Derived von Willebrand Factor Is the Major Determinant That Mediates von Willebrand Factor-Dependent Acute Ischemic Stroke by Promoting Postischemic Thrombo-Inflammation.

Objective: von Willebrand factor (VWF), which is synthesized in endothelial cells and megakaryocytes, is known to worsen stroke outcome. In vitro studies suggest that platelet-derived VWF (Plt-VWF) is biochemically different from the endothelial cell-derived VWF (EC-VWF). However, little is known about relative contribution of different pools of VWF in stroke.

Protein methionine oxidation augments reperfusion injury in acute ischemic stroke.

Reperfusion injury can exacerbate tissue damage in ischemic stroke, but little is known about the mechanisms linking ROS to stroke severity. Here, we tested the hypothesis that protein methionine oxidation potentiates NF-κB activation and contributes to cerebral ischemia/reperfusion injury. We found that overexpression of methionine sulfoxide reductase A (MsrA), an antioxidant enzyme that reverses protein methionine oxidation, attenuated ROS-augmented NF-κB activation in endothelial cells, in part, by protecting against the oxidation of methionine residues in the regulatory domain of calcium/calmodulin-dependent protein kinase II (CaMKII).

Monoglyceride lipase deficiency modulates endocannabinoid signaling and improves plaque stability in ApoE-knockout mice.

Background And Aims: Monoglyceride lipase (MGL) catalyzes the final step of lipolysis by degrading monoglyceride (MG) to glycerol and fatty acid. MGL also hydrolyzes and thereby deactivates 2-arachidonoyl glycerol (2-AG), the most abundant endocannabinoid in the mammalian system. 2-AG acts as full agonist on cannabinoid receptor type 1 (CB1R) and CB2R, which are mainly expressed in brain and immune cells, respectively.

Genetic Ablation of Extra Domain A of Fibronectin in Hypercholesterolemic Mice Improves Stroke Outcome by Reducing Thrombo-Inflammation.

Background: The fibronectin-splicing variant containing extra domain A (Fn-EDA) is present in negligible amounts in the plasma of healthy humans but markedly elevated in patients with comorbid conditions, including diabetes mellitus and hypercholesterolemia, which are risk factors for stroke. It remains unknown, however, whether Fn-EDA worsens stroke outcomes in such conditions. We determined the role of Fn-EDA in stroke outcome in a model of hypercholesterolemia, the apolipoprotein E-deficient (Apoe(-/-)) mouse.

Deletion of Methionine Sulfoxide Reductase A Does Not Affect Atherothrombosis but Promotes Neointimal Hyperplasia and Extracellular Signal-Regulated Kinase 1/2 Signaling.

Objective: Emerging evidence suggests that methionine oxidation can directly affect protein function and may be linked to cardiovascular disease. The objective of this study was to define the role of the methionine sulfoxide reductase A (MsrA) in models of vascular disease and identify its signaling pathways.

Approach And Results: MsrA was readily identified in all layers of the vascular wall in human and murine arteries.

Fibronectin Splicing Variants Containing Extra Domain A Promote Atherosclerosis in Mice Through Toll-Like Receptor 4.

Objective: Cellular fibronectin containing extra domain A (EDA(+)-FN) is abundant in the arteries of patients with atherosclerosis. Several in vitro studies suggest that EDA(+)-FN interacts with Toll-like receptor 4 (TLR4). We tested the hypothesis that EDA(+)-FN exacerbates atherosclerosis through TLR4 in a clinically relevant model of atherosclerosis, the apolipoprotein E-deficient (Apoe(-/-)) mouse.

Active autophagy but not lipophagy in macrophages with defective lipolysis.

During autophagy, autophagosomes fuse with lysosomes to degrade damaged organelles and misfolded proteins. Breakdown products are released into the cytosol and contribute to energy and metabolic building block supply, especially during starvation. Lipophagy has been defined as the autophagy-mediated degradation of lipid droplets (LDs) by lysosomal acid lipase.

Xanthohumol ameliorates atherosclerotic plaque formation, hypercholesterolemia, and hepatic steatosis in ApoE-deficient mice.

Scope: Xanthohumol (XN), a prenylated antioxidative and anti-inflammatory chalcone from hops, exhibits positive effects on lipid and glucose metabolism. Based on its favorable biological properties, we investigated whether XN attenuates atherosclerosis in western-type diet-fed apolipoprotein-E-deficient (ApoE⁻/⁻) mice.

Methods And Results: XN supplementation markedly reduced plasma cholesterol concentrations, decreased atherosclerotic lesion area, and attenuated plasma concentrations of the proinflammatory cytokine monocyte chemoattractant protein 1.