PB0750 - Platelets promote neutrophil extracellular traps mediated thrombo-inflammation and glomerular endothelial dysfunction in diabetic kidney disease

Background: Diabetic kidney disease (DKD) is a major cause of end-stage renal failure and is associated with endothelial dysfunction, platelet hyperactivity, immune cell infiltration and dysfunctional glomerular filtration barrier. Mechanistic insights into the role of platelets for DKD progression are limited.

Aims: We aim to scrutinize the mechanistic interplay between platelets and neutrophil extracellular traps (NET) and ensuing renal thrombo-inflammation in DKD.

Methods: Renal function, platelet activation (immunostaining) and NET formation (immunostaining, ELISA) was evaluated in streptozotocin induced type 1 diabetic mice model. Pharmacological interventions were performed in sub groups of mice to evaluate the platelets and NETs. In vitro studies were performed using glomerular endothelial cells (GENC), platelets and neutrophils exposed to high glucose under static and flow conditions.

Results: Diabetic glomerulus in mice showed increased activated platelets (CD62P) and NETs (MPO, H3Cit) and positively correlated with DKD progression (urinary albumin-creatinine ratio, nephrin expression), glomerular endothelial dysfunction (p-eNOS) and glomerular inflammasome activation (NLRP3, IL1β). Pharmacological targeting of platelet activation (Aspirin or Ticagrelor), NET formation (PAD4 inhibition; GSK484), or blocking platelet-neutrophil interaction via P-selectin ligand blocking (αPSGL-1) ameliorated these effects. In humans, plasma NETs correlated with DKD severity and were increased in kidneys of DKD patients. In vitro, addition of platelets exacerbated high glucose and NET induced endothelial dysfunction (p-eNOS, KLF2, KLF4 and TM), inflammasome activation (IL1β, NLRP3) and glomerular filtration barrier disruption (enhanced FITC albumin leakage, disoriented VE cadherin). Under flow conditions, platelets promote high glucose induced NET formation on GENCs.

Conclusion(s): Our data identifies a mechanistic role of platelets in DKD by enhancing glomerular NETs. Platelets aggravate the disease course in DKD via platelet-neutrophil interactions resulting in NETs and exacerbate the ensuing glomerular endothelial sterile inflammation, glomerular endothelial dysfunction, barrier disruption and cell death. Therefore, inhibition of platelets, or their interactions is a promising therapeutic strategy for DKD.