Biology subjects

Dhawan, U. K.

Publications and source records attributed to Dhawan, U. K..

2 recordsLinked to original sources

bioRxiv2025

Impaired Macrophage DNase Secretion Promotes Neutrophil Extracellular Trap Mediated Defective Efferocytosis in Atherosclerosis

Neutrophil extracellular traps (NETs) drive atherosclerosis progression and are associated with adverse clinical outcomes like myocardial infarction and stroke. While the triggers of NETosis in atherosclerotic plaque are well-characterized, the mechanisms underlying NET degradation and clearance remain unclear. Moreover, the impact of impaired NET clearance on atherosclerosis progression have not been elucidated. Here we show that macrophages are critical for the release of DNases, which degrade NETs. We identified endoplasmic reticulum (ER) stress mediated activation of PERK-ATF4 pathway as a key driver of impaired macrophage DNase secretion, leading to delayed NET clearance and their persistence. Elevated NET levels trigger cleavage of the efferocytosis receptor Mertk leading to defective macrophage efferocytosis and exacerbation of plaque necrosis. Human atherosclerotic plaques and Ldlr-/- mice treated with ISRIB, a PERK inhibitor, show enhanced DNase secretion and clearance of NETs. Together, the identification of key mechanisms of NET clearance in atherosclerosis offers new therapeutic strategies to stabilize plaques.

pathology↗

bioRxiv2020

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

Defects 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.

immunology↗