Platelet hyperactivation and neutrophil extracellular traps promote thrombo-inflammation and glomerular endothelial dysfunction in diabetic kidney disease

Introduction Diabetic kidney disease (DKD) is the cause of end-stage renal failure and contributes to morbidity and mortality worldwide. However, therapeutic options that ameliorate or reverse the progression of DKD are limited. Endothelial dysfunction, platelet hyperactivity, immune cell infiltration and glomerular filtration barrier disruption are associated with DKD. Therefore, we aimed to scrutinize the mechanistic interplay between platelets and neutrophil extracellular traps (NETs) and ensuing renal thrombo-inflammation. These insights may identify new avenues to prevent or reverse DKD. Method Streptozotocin induced type 1 diabetic mice were used to evaluate renal function, platelet activation and NET formation. Therapeutic interventions (ASA, Anakinra, Solulin, GSK484, Ticagrelor, PSGL blocking) were performed in sub groups of mice with drugs starting at 16 weeks of diabetes until 24 weeks to study disease reversal. In vitro studies were performed using glomerular endothelial cells (GENC), platelets and neutrophils exposed to high glucose. Results Experimental DKD in C57Bl6 mice resulted in albuminuria, increased fractional mesangial area, activated platelets (CD62P) and neutrophil extracellular traps (NETs; CitH3, NE, PAD4, MPO) within glomeruli. In parallel, increased expression of inflammasome markers (NLRP3, IL1β) and reduced expression of coagulation regulator thrombomodulin (TM) was observed. In vitro, platelets exacerbate NETs mediated inflammasome markers (IL1β, NLRP3), reduce endothelial function markers (p-eNOS, KLF2, KLF4 and TM) in GENC under high glucose stress. Furthermore, high glucose induced platelet-neutrophil interaction and resulting NET formation disrupted the glomerular filtration barrier In vitro (enhanced FITC-dextran leakage, disoriented VE cadherin). Under flow condition, exposure to high glucose resulted in enhanced NET formation on GENC monolayers which got accelerated in the presence of platelets. Inhibition of platelet activation (ASA or Ticagrelor), amelioration of NETs by inhibition of histone citrullination (PAD4 inhibition;(GSK484), inhibition of platelet-neutrophil interaction via P selectin ligand blocking antibody, IL-1 receptor inhibition (anakinra), restoring TM expression (solulin), ameliorated these effects. The treatment with these inhibitors in diabetic mice after the onset of DKD resulted in disease reversal [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]. Conclusion Taken together, hyperglycemia promotes platelet-neutrophil interactions resulting in NETs, activation of clotting system, endothelial sterile inflammation, glomerular endothelial dysfunction, barrier disruption and cell death. This results in aggravated disease course and impaired renal health in DKD. Inhibition of platelets or NETs is a promising therapeutic strategy for DKD. Publication History Article published online: 20 February 2023 © 2023. Thieme. All rights reserved. Georg Thieme Verlag Rüdigerstraße 14, 70469 Stuttgart, Germany