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Abstract: FR-PO349

Oxidised IL-33 Mediates Proximal Tubular Injury Through the RAGE/EGFR Pathway

Session Information

Category: Diabetic Kidney Disease

  • 701 Diabetic Kidney Disease: Basic

Authors

  • Liarte Marin, Elena, Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
  • Musial, Barbara, Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
  • Bousfield, Philip Marcus, Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
  • Seth, Asha, Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
  • Laerkegaard Hansen, Pernille B., Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
  • Woollard, Kevin, Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
Background

We previously described IL-33 role in DKD mediating glomerular endothelial inflammation through ST2 signalling and a Ph2b trial in DKD using tozorakimab (anti-IL-33 mAb) is ongoing (FRONTEIR-1). Recently, IL-33 was shown to get oxidised extracellularly (IL-33ox) and exert distinct activity through a novel RAGE/EGFR complex to modulate lung epithelial remodelling. As ST2 and RAGE/EGFR act as putative receptors, we explored IL-33ox and RAGE/EGFR signalling role in kidney.

Methods

Whilst RAGE is a promiscuous receptor, blockade of RAGE signalling with a neutralising antibody prevented progression of albuminuria in the db/db uninephrectomy model. Mechanistic studies were further developed using primary human glomerular endothelial (GEC) and proximal tubular epithelial cells (PTEC) to address IL-33ox-RAGE/EGFR pathway contribution to human DKD.

Results

GEC but not PTEC expressed ST2 and hence reduced IL-33 (IL-33red) did not display an inflammatory response in PTEC contrary to the effects seen in GEC. However, IL-33ox stimulation of PTEC promoted EGF receptor activation which was inhibited by antibodies against EGFR and RAGE. IL-33ox led to phosphorylation of EGFR downstream signalling molecules, like ERK1/ 2 but no other MAP kinases. Data also showed IL-33ox upregulated epithelial injury markers (KIM-1) and inflammatory cytokine release in PTEC.

Preliminary results indicated that IL-33ox modulates epithelial biological functions that could impact healing and reparative mechanisms in the context of DKD. Under normal culture conditions IL-33ox but not IL-33red stimulated PTEC proliferation, while under stress (serum starvation) IL-33ox prevented this effect. In a PTEC wound closure assay, tozorakimab facilitated wound healing suggesting oxidation inhibition of endogenously secreted IL-33 by the injured epithelium.

GEC biology was assessed too. In contrast to the endothelial inflammation caused through the IL-33red/ST2 pathway, minimal effects were observed upon IL-33ox stimulation.

Conclusion

Although mechanism of action of the IL-33ox–RAGE/EGFR pathway still needs to be fully elucidated, our results suggest that IL-33ox can contribute to tubular epithelial repair and remodelling. Tozorakimab may therefore be beneficial in DKD by preventing IL-33red mediated glomerular inflammation and IL33ox mediated tubular injury.

Funding

  • Commercial Support – AstraZeneca