scholarly journals Hypercholesterolemia Impairs Clearance of Neutrophil Extracellular Traps and Promotes Inflammation and Atherosclerotic Plaque Progression

2021 ◽  
Author(s):  
Umesh Kumar Dhawan ◽  
Purbasha Bhattacharya ◽  
Sriram Narayanan ◽  
Vijayprakash Manickam ◽  
Ayush Aggarwal ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Atherosclerotic Plaque ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Dnase Activity ◽  
Plaque Progression ◽  
Chemical Chaperone ◽  
Extracellular Traps ◽  
Inflammation Resolution

Objective: Hypercholesterolemia-induced NETosis and accumulation of neutrophil extracellular traps (NETs) in the atherosclerotic lesion exacerbates inflammation and is causally implicated in plaque progression. We investigated whether hypercholesterolemia additionally impairs the clearance of NETs mediated by endonucleases such as DNase1 and DNase1L3 and its implication in advanced atherosclerotic plaque progression. Approach and Results: Using a mouse model, we demonstrate that an experimental increase in the systemic level of NETs leads to a rapid increase in serum DNase activity, which is critical for the prompt clearance of NETs and achieving inflammation resolution. Importantly, hypercholesterolemic mice demonstrate an impairment in this critical NET-induced DNase response with consequent delay in the clearance of NETs and defective inflammation resolution. Administration of TUDCA, a chemical chaperone that relieves endoplasmic reticulum stress, rescued the hypercholesterolemia-induced impairment in the NET-induced DNase response suggesting a causal role for endoplasmic reticulum stress in this phenomenon. Correction of the defective DNase response with exogenous supplementation of DNase1 in Apoe −/− mice with advanced atherosclerosis resulted in a decrease in plaque NET content and significant plaque remodeling with decreased area of plaque necrosis and increased collagen content. From a translational standpoint, we demonstrate that humans with hypercholesterolemia have elevated systemic extracellular DNA levels and decreased plasma DNase activity. Conclusions: These data suggest that hypercholesterolemia impairs the NET-induced DNase response resulting in defective clearance and accumulation of NETs in the atherosclerotic plaque. Therefore, strategies aimed at rescuing this defect could be of potential therapeutic benefit in promoting inflammation resolution and atherosclerotic plaque stabilization.

scholarly journals Hypercholesterolemia Impairs Clearance of Extracellular DNA and Promotes Inflammation and Atherosclerotic Plaque Progression

2020 ◽  
Author(s):  
Umesh Kumar Dhawan ◽  
Purbasha Bhattacharya ◽  
Sriram Narayanan ◽  
Vijayprakash Manickam ◽  
Ayush Aggarwal ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Therapeutic Strategy ◽  
Inflammatory Diseases ◽  
Extracellular Dna ◽  
Plaque Progression ◽  
Pathological Features ◽  
Physiological Mechanisms ◽  
Optimal Activity ◽  
Vulnerable Plaques ◽  
Inflammation Resolution

AbstractDefects in clearance of extracellular DNA due to sub-optimal activity of DNase results in exacerbated inflammation and contributes to the pathophysiology of atherosclerosis and other inflammatory diseases. However, the physiological mechanisms that regulate systemic DNase levels and the basis of its functional impairment during disease are poorly understood. Using a mouse model of experimental increase in systemic extracellular DNA levels, we identify the existence of a physiologic DNA-induced DNase response. Importantly, hypercholesterolemia in mice impairs this critical DNA-induced DNase response through an endoplasmic reticulum stress-mediated mechanism with consequences in advanced atherosclerotic plaque progression including increased extracellular DNA accumulation, exacerbated inflammation, and development of pathological features of necrotic rupture-prone vulnerable plaques. From a translational standpoint in humans, we demonstrate that individuals with hypercholesterolemia have elevated systemic extracellular DNA levels and decreased plasma DNase activity. These data suggest that the restoration of DNA-induced DNase response could be a potential therapeutic strategy to promote inflammation resolution during hypercholesterolemia.

scholarly journals Detailed histological analysis of a thrombectomy-resistant ischemic stroke thrombus: a case report

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Senna Staessens ◽  
Olivier François ◽  
Linda Desender ◽  
Peter Vanacker ◽  
Tom Dewaele ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Von Willebrand Factor ◽  
Histological Analysis ◽  
Mechanical Thrombectomy ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Extracellular Traps ◽  
First Pass ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Background Mechanical removal of a thrombus by thrombectomy can be quite challenging. For reasons that are not fully understood, some thrombi require multiple passes to achieve successful recanalization, whereas other thrombi are efficiently removed in a single pass. Since first pass success is associated with better clinical outcome, it is important to better understand the nature of thrombectomy resistant thrombi. The aim of this study was therefore to characterize the cellular and molecular composition of a thrombus that was very hard to retrieve via mechanical thrombectomy. Case presentation In a patient that was admitted with a right middle cerebral artery M1-occlusion, 11 attempts using various thrombectomy devices and techniques were required for removal of the thrombus. This peculiar case provided a rare opportunity to perform an in-depth histopathological study of a difficult to retrieve thrombus. Thrombus material was histologically analyzed using hematoxylin and eosin, Martius Scarlet Blue stain (red blood cells and fibrin), Feulgen stain (DNA), von Kossa stain (calcifications) and immunohistochemical analysis of von Willebrand factor, platelets, leukocytes and neutrophil extracellular traps. Histological analysis revealed abnormally high amounts of extracellular DNA, leukocytes, von Willebrand factor and calcifications. Extracellular DNA stained positive for markers of leukocytes and NETs, suggesting that a significant portion of DNA is derived from neutrophil extracellular traps. Conclusion In this unique case of a nearly thrombectomy-resistant stroke thrombus, our study showed an atypical composition compared to the common structural features found in ischemic stroke thrombi. The core of the retrieved thrombus consisted of extracellular DNA that colocalized with von Willebrand factor and microcalcifications. These results support the hypothesis that von Willebrand factor, neutrophil extracellular traps and microcalcifications contribute to mechanical thrombectomy resistance. Such information is important to identify novel targets in order to optimize technical treatment protocols and techniques to increase first pass success rates.

scholarly journals Neutrophil Extracellular Traps Promote the Development and Growth of Human Salivary Stones

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2139
Author(s):  
Mirco Schapher ◽  
Michael Koch ◽  
Daniela Weidner ◽  
Michael Scholz ◽  
Stefan Wirtz ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Clinical Symptoms ◽  
Neutrophil Extracellular Traps ◽  
Physicochemical Process ◽  
Extracellular Dna ◽  
Neutrophil Granulocyte ◽  
Extracellular Traps ◽  
Efferent Ducts ◽  
Small Crystals

Salivary gland stones, or sialoliths, are the most common cause of the obstruction of salivary glands. The mechanism behind the formation of sialoliths has been elusive. Symptomatic sialolithiasis has a prevalence of 0.45% in the general population, is characterized by recurrent painful periprandial swelling of the affected gland, and often results in sialadenitis with the need for surgical intervention. Here, we show by the use of immunohistochemistry, immunofluorescence, computed tomography (CT) scans and reconstructions, special dye techniques, bacterial genotyping, and enzyme activity analyses that neutrophil extracellular traps (NETs) initiate the formation and growth of sialoliths in humans. The deposition of neutrophil granulocyte extracellular DNA around small crystals results in the dense aggregation of the latter, and the subsequent mineralization creates alternating layers of dense mineral, which are predominantly calcium salt deposits and DNA. The further agglomeration and appositional growth of these structures promotes the development of macroscopic sialoliths that finally occlude the efferent ducts of the salivary glands, causing clinical symptoms and salivary gland dysfunction. These findings provide an entirely novel insight into the mechanism of sialolithogenesis, in which an immune system-mediated response essentially participates in the physicochemical process of concrement formation and growth.

The screening of albumin as a key serum component to prevent neutrophil extracellular traps release by selectively inhibiting mitochondrial ROS generation

2020 ◽  
Author(s):  
Yue Zheng ◽  
Yuanfeng Zhu ◽  
Xin Liu ◽  
Hang Zheng ◽  
Yongjun Yang ◽  
...  
Keyword(s):  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Organ Injury ◽  
Ros Generation ◽  
Ros Production ◽  
Serum Free ◽  
Extracellular Traps ◽  
Mitochondrial Ros ◽  
Serum Component ◽  
Microbial Defense

Neutrophil extracellular traps (NETs) are extracellular DNA webs released from neutrophils to mediate host anti-microbial defense. As NETs could also induce thrombosis and cause organ injury, their release should be strictly controlled. However, it is not well understood about the intrinsic mechanisms that prevent unfavorable NETs. Herein, an accidental finding of NETs release from human peripheral neutrophils was firstly described in serum free culture, and it was also determined as a conserved effect for serum to prevent NETs. In contrast to canonical NETs induced by phorbol-12-myristate-13-acetate (PMA), NETs formation by serum free culture was rapid and without prevalent NETosis. Next, albumin was screened out as a key serum component that mediated the suppression of NETs. Moreover, NETs induced upon serum or albumin deficiency were independent of the canonical pathway that involves NOX2 activation and cytosol ROS production. Instead, the generation of mitochondrial ROS (mtROS) was upregulated to promote NETs release. Albumin exhibited mtROS scavenging activity and thus inhibited NETs. Serum free culture also induces the release of NET-bound oxidized mtDNA which stimulated IFN-β production. Overall, our research provides new evidences that characterize the NETs production in serum free culture and determine the mechanisms of serum albumin to inhibit NETs.

Proinflammatory role of neutrophil extracellular traps in abdominal sepsis

2014 ◽  
Vol 307 (7) ◽  
pp. L586-L596 ◽  
Author(s):  
Lingtao Luo ◽  
Su Zhang ◽  
Yongzhi Wang ◽  
Milladur Rahman ◽  
Ingvar Syk ◽  
...  
Keyword(s):  
Lung Injury ◽  
Peritoneal Cavity ◽  
Tissue Injury ◽  
Cecal Ligation ◽  
Neutrophil Extracellular Traps ◽  
Abdominal Sepsis ◽  
Extracellular Dna ◽  
Extracellular Traps ◽  
Proinflammatory Role

Excessive neutrophil activation is a major component in septic lung injury. Neutrophil-derived DNA may form extracellular traps in response to bacterial invasions. The aim of the present study was to investigate the potential role of neutrophil extracellular traps (NETs) in septic lung injury. Male C57BL/6 mice were treated with recombinant human (rh)DNAse (5 mg/kg) after cecal ligation and puncture (CLP). Extracellular DNA was stained by Sytox green, and NET formation was quantified by confocal microscopy and cell-free DNA in plasma, peritoneal cavity, and lung. Blood, peritoneal fluid, and lung tissue were harvested for analysis of neutrophil infiltration, NET levels, tissue injury, as well as CXC chemokine and cytokine formation. We observed that CLP caused increased formation of NETs in plasma, peritoneal cavity, and lung. Administration of rhDNAse not only eliminated NET formation in plasma, peritoneal cavity, and bronchoalveolar space but also reduced lung edema and tissue damage 24 h after CLP induction. Moreover, treatment with rhDNAse decreased CLP-induced formation of CXC chemokines, IL-6, and high-mobility group box 1 (HMGB1) in plasma, as well as CXC chemokines and IL-6 in the lung. In vitro, we found that neutrophil-derived NETs had the capacity to stimulate secretion of CXCL2, TNF-α, and HMGB1 from alveolar macrophages. Taken together, our findings show that NETs regulate pulmonary infiltration of neutrophils and tissue injury via formation of proinflammatory compounds in abdominal sepsis. Thus we conclude that NETs exert a proinflammatory role in septic lung injury.

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