TWEAK transactivation of the epidermal growth factor receptor mediates renal inflammation.

TWEAK, a member of the TNF superfamily, binds to the Fn14 receptor, eliciting biological responses. EGFR signalling is involved in experimental renal injury. Our aim was to investigate the relationship between TWEAK and EGFR in the kidney. Systemic TWEAK administration into C57BL/6 mice increased renal EGFR phosphorylation, mainly in tubular epithelial cells. In vitro, in these cells TWEAK phosphorylated EGFR via Fn14 binding, ADAM17 activation and subsequent release of the EGFR ligands HB-EGF and TGFα. In vivo the EGFR kinase inhibitor Erlotinib inhibited TWEAK-induced renal EGFR activation and downstream signalling, including ERK activation, up-regulation of proinflammatory factors and inflammatory cell infiltration. Moreover, the ADAM17 inhibitor WTACE-2 also prevented those TWEAK-induced renal effects. In vitro TWEAK induction of proinflammatory factors was prevented by EGFR, ERK or ADAM17 inhibition. In contrast, EGFR transactivation did not modify TWEAK-mediated NF-κB activation. Our data suggest that TWEAK transactivates EGFR in the kidney, leading to modulation of downstream effects, including ERK activation and inflammation, and suggest that inhibition of EGFR signalling could be a novel therapeutic tool for renal inflammation.