Necroptosis controls NET generation and mediates complement activation, endothelial damage, and autoimmune vasculitis

Abstract

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) constitutes life-threatening autoimmune diseases affecting every organ, including the kidneys, where they cause necrotizing crescentic glomerulonephritis. ANCA activates neutrophils and activated neutrophils damage the endothelium, leading to vascular inflammation and necrosis. Better understanding of neutrophil-mediated AAV disease mechanisms may reveal novel treatment strategies. Here we report that ANCA induces neutrophil extracellular traps (NETs) via receptor-interacting protein kinase (RIPK) 1/3- and mixed-lineage kinase domain-like (MLKL)-dependent necroptosis. NETs from ANCA-stimulated neutrophils caused endothelial cell (EC) damage in vitro. This effect was prevented by () pharmacologic inhibition of RIPK1 or () enzymatic NET degradation. The alternative complement pathway (AP) was recently implicated in AAV, and C5a inhibition is currently being tested in clinical studies. We observed that NETs provided a scaffold for AP activation that in turn contributed to EC damage. We further established the in vivo relevance of NETs and the requirement of RIPK1/3/MLKL-dependent necroptosis, specifically in the bone marrow-derived compartment, for disease induction using murine AAV models and in human kidney biopsies. In summary, we identified a mechanistic link between ANCA-induced neutrophil activation, necroptosis, NETs, the AP, and endothelial damage. RIPK1 inhibitors are currently being evaluated in clinical trials and exhibit a novel therapeutic strategy in AAV.

Cell Death Pathways Drive Necroinflammation during Acute Kidney Injury

“…This may not exclusively be the case for systemic lupus erythematosus (SLE), but also for other autoimmune diseases. One such example that causes AKI may be ANCA-associated vasculitis [19]. fore facilitated the assessment of ferroptosis-interference in vivo in models of AKI.…”

Necroptosis in Acute Kidney Injury

“…Transplantation of bone marrow harvested from Ripk3 -deficient mice into wild type mice protected the recipients from glomerular injury [18]. This implies a role of RIPK3-mediated necroptosis for neutrophil necroptosis and neutrophil extracellular trap-related glomerular injury, a concept supported by effective in vitro experiments by the same group [18].…”

“…Transplantation of bone marrow harvested from Ripk3 -deficient mice into wild type mice protected the recipients from glomerular injury [18]. This implies a role of RIPK3-mediated necroptosis for neutrophil necroptosis and neutrophil extracellular trap-related glomerular injury, a concept supported by effective in vitro experiments by the same group [18]. Indeed, neutrophil necroptosis has also been reported using other triggers, for example, phorbol 12-myristate 13-acetate or crystalline microparticles using neutrophils isolated from Ripk3- ( and Mlkl)- deficient mice [19, 20].…”

“…Therefore, Mlkl- deficient mice are currently the ultimate experimental tool to generate undisputable evidence for an involvement of necroptosis in AKI. Mlkl- deficient mice display a consistent attenuation in the following experimental AKI models: post-ischemic AKI (Table 1) [3, 15], cisplatin-induced AKI [8], oxalate nephropathy [10], and MPO-ANCA-induced glomerular injury [18]. The fact that lack of MLKL had a much lesser effect on survival upon post-ischemic AKI as compared to ­ Ripk1 KD and Ripk3 –/– mice suggests that the contribution of necroptosis in post-ischemic AKI may indeed be overestimated by using less specific tools such as Ripk3- deficient mice or Nec-1 [3].…”

Neutrophil extracellular traps activate lung fibroblast to induce polymyositis‐related interstitial lung diseases via TLR9‐miR‐7‐Smad2 pathway

“…[30][31][32] NETs also involve in the development of inflammation through inducing the release of cytokine by airway epithelial cells. Our experimental data suggested that NETs Increasing evidence has shown that NETs and their components cause damage of endothelial and epithelial cells, thus to impair pulmonary function and accelerate the progress of chronic obstructive pulmonary disease.…”