POS-438 KIDNEYS ON FIRE: DECIPHERING THE ROLE OF INFLAMMASOME ACTIVATION IN HUMAN CHRONIC KIDNEY DISEASE (CKD)

Tubulointerstitial fibrosis and inflammation are hallmarks of chronic kidney disease (CKD). Key among the up-stream drivers pathobiology is hypoxia, resulting in cellular stress. Hypoxia particularly damaging to proximal tubule epithelial cells (PTEC) due their high metabolic activity, release danger-signals cell death. We previously identified an activated innate immune population CD1c+ dendritic (DC) adjacent damaged PTEC human CKD, where DC well situated respond danger-signals. Animal models CKD have established that NLRP3 inflammasome, sensor danger-signals, plays a key role driving tubulointerstitial fibrosis. inflammasome activation initiates, via caspase-1, proteolytic cleavage interleukin (IL)-1β, proinflammatory cytokine. Here we sought define these pathobiological pathways assessing: (1) markers oxidative stress danger-signals; (2) critical death PTEC; (3) inflammasome. Primary were cultured vitro under normoxia (21% O2) hypoxia (1% O2), before assessment stress/lipid peroxidation by immunofluorescence microscopy flow cytometry. Danger-signals assessed ELISA. Western blotting was used assess central regulators apoptosis (caspase-3), necrosis (p-MLKL) ferroptosis (GPX4). Hypoxic PTEC-CD1c+ interactions examined co-culture absence or presence specific caspase-1 inhibitors, with IL-1β secretion (cytokine bead array). The histological location complex cell-cell signalling determine multi-fluorescence staining biopsies. primary had elevated 4-hydroxynoneal (4-HNE), phospholipid by-product. supernatant significant increase necrotic danger-signal HMGB1, potent activator. Ferroptosis mechanism hypoxic as indicated significantly reduced glutathione peroxidase, repair enzyme. induced than control normoxic co-cultures. This attenuated either MCC950 (a inhibitor) VX-765 inhibitor). These validated biopsies people 4-HNE expression enhanced compartment. localised areas expressed active specks (ASC). provide first confirmation pathways, only animal models, CKD. Our data evidence that: display lipid secrete danger-signal; predominant pathway driven model CKD; within response pro-inflammatory cytokine Further investigation into processes may advance identification future targets for therapeutic intervention diagnostic detection