title: TWEAK activates the non-canonical NFkappaB pathway in murine renal tubular cells: modulation of CCL21.
abstract: TWEAK is a member of the TNF superfamily of cytokines that contribute to kidney tubulointerstitial injury. It has previously been reported that TWEAK induces transient nuclear translocation of RelA and expression of RelA-dependent cytokines in renal tubular cells. Additionally, TWEAK induced long-lasting NFkappaB activation suggestive of engagement of the non-canonical NFkappaB pathway. We now explore TWEAK-induced activation of NFkappaB2 and RelB, as well as expression of CCL21, a T-cell chemotactic factor, in cultured murine tubular epithelial cells and in healthy kidneys in vivo. In cultured tubular cells, TWEAK and TNFalpha activated different DNA-binding NFkappaB complexes. TWEAK-induced sustained NFkappaB activation was associated with NFkappaB2 p100 processing to p52 via proteasome and nuclear translocation and DNA-binding of p52 and RelB. TWEAK, but not TNFalpha used as control), induced a delayed increase in CCL21a mRNA (3.5+/-1.22-fold over control) and CCL21 protein (2.5+/-0.8-fold over control), which was prevented by inhibition of the proteasome, or siRNA targeting of NIK or RelB, but not by RelA inhibition with parthenolide. A second NFkappaB2-dependent chemokine, CCL19, was upregulates by TWEAK, but not by TNFalpha. However, both cytokines promoted chemokine RANTES expression (3-fold mRNA at 24 h). In vivo, TWEAK induced nuclear NFkappaB2 and RelB translocation and CCL21a mRNA (1.5+/-0.3-fold over control) and CCL21 protein (1.6+/-0.5-fold over control) expression in normal kidney. Increased tubular nuclear RelB and tubular CCL21 expression in acute kidney injury were decreased by neutralization (2+/-0.9 vs 1.3+/-0.6-fold over healthy control) or deficiency of TWEAK (2+/-0.9 vs 0.8+/-0.6-fold over healthy control). Moreover, anti-TWEAK treatment prevented the recruitment of T cells to the kidney in this model (4.1+/-1.4 vs 1.8+/-1-fold over healthy control). Our results thus identify TWEAK as a regulator of non-canonical NFkappaB activation and CCL21 expression in tubular cells thus promoting lymphocyte recruitment to the kidney during acute injury.
authors.affiliation: Servicio de Nefrologia, Fundación para la Investigación Biomédica del Hospital Universitario La Paz, Madrid, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Sanz
authors.forename: Maria D
authors.initials: MD
authors.lastname: Sanchez-Niño
authors.forename: Maria C
authors.initials: MC
authors.lastname: Izquierdo
authors.forename: Aniela
authors.initials: A
authors.lastname: Jakubowski
authors.forename: Pilar
authors.initials: P
authors.lastname: Justo
authors.forename: Luis M
authors.initials: LM
authors.lastname: Blanco-Colio
authors.forename: Marta
authors.initials: M
authors.lastname: Ruiz-Ortega
authors.forename: Rafael
authors.initials: R
authors.lastname: Selgas
authors.forename: Jesús
authors.initials: J
authors.lastname: Egido
authors.forename: Alberto
authors.initials: A
authors.lastname: Ortiz
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D054421:Chemokine CCL21 / Q000502:physiology*; D000074049:Cytokine TWEAK; D004797:Enzyme-Linked Immunosorbent Assay; D007684:Kidney Tubules / Q000502:physiology*; D051379:Mice; D018613:Microscopy, Confocal; D016328:NF-kappa B / Q000502:physiology*; D048069:Tumor Necrosis Factors / Q000502:physiology*
chemical_list: D054421:Chemokine CCL21; D000074049:Cytokine TWEAK; D016328:NF-kappa B; C491645:Tnfsf12 protein, mouse; D048069:Tumor Necrosis Factors