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

Abstract

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.

Identification of hub genes and immune cell infiltration participating in the progression of carotid atherosclerotic plaques

“…One of the earlier studies showed that the regulatory T cells (Tregs) activate anti-in ammatory macrophages, suppress the formation of foam cells, and affect cholesterol metabolism, all of which have an atherosclerosis-preventing effect [9]. In contrast, macrophages, and neutrophil extracellular traps (NETs) were shown to promote in ammation and atherosclerotic plaque progression [10,11]. Although prior research has shown that different immune cells and immune system-related pathways were involved in the progression of carotid atherosclerotic plaques, none of the reports have determined the major molecular processes and how they interact with the in ammation-linked pathways to control the progression of the carotid atherosclerotic plaques.…”

Hypercholesterolemia promotes autoantibody production and a lupus‐like pathology via decreased DNase‐mediated clearance of DNA

“…However, acute elevation of extracellular DNA, such as that happens during an acute inflammatory response, requires rapid systemic elevation of DNase activity to restore homeostasis and prevent the onset of an inflammatory response. 10 Interestingly, several autoimmune diseases are associated with decreased systemic DNase activity, increased extracellular DNA levels, and increased anti‐ds‐DNA autoantibodies. 10 , 11 , 12 , 13 , 14 For example, the decreased DNase activity in systemic lupus erythematosus (SLE) is associated with either single nucleotide polymorphisms (SNPs) or mutations in DNase1/DNase1L3 15 , 16 , 17 , 18 , 19 , 20 or the presence of neutralizing antibodies which block the activity of DNase1/DNase1L3.…”

Expressão de desoxirribonucleases endógenas envolvidas na degradação das armadilhas extracelulares de neutrófilos em camundongos com sepse experimental

“…A depuração das NETs é mediada por desoxirribonucleases (DNases), que degradam o arcabouço de DNA das NETs e facilitam a sua fagocitose por macrófagos (18,19).…”

“…A TREX1 é uma DNase intracelular, que fica ancorada na membrana nuclear, e, portanto, dependeria da entrada das NETs nas células para degradação (23). A DNase 1 é secretada e tem sua expressão principalmente no pâncreas e por glândulas salivares (19,20,22), podendo também ser expressa no trato gastrointestinal e nos rins (24). Essa é a principal DNase presente no soro de humanos e de camundongos, é juntamente com a DNase γ, é responsável pela maior parte da atividade DNase detectada nesse tipo de amostra (24).…”

“…Essa DNase tem uma maior capacidade de degradar DNA ligado a proteínas e no interior de lipossomas, por contar com uma porção C-terminal com carga positiva (26). A DNase X, também conhecida por DNase 1L1, é uma enzima ancorada a membrana externa da célula, que possui expressão ampla em diversos compartimentos, sendo principalmente expressa por células musculares cardíacas ou esqueléticas, no fígado e por leucócitos, entre eles os macrófagos (19,20,22,27).…”