Experimental inhibition of porcupine-mediated Wnt O-acylation attenuates kidney fibrosis.


Activated Wnt signaling is critical in the pathogenesis of renal fibrosis, a final common pathway for most forms of chronic kidney disease. Therapeutic intervention by inhibition of individual Wnts or downstream Wnt/β-catenin signaling has been proposed, but these approaches do not interrupt the functions of all Wnts nor block non-canonical Wnt signaling pathways. Alternatively, an orally bioavailable small molecule, Wnt-C59, blocks the catalytic activity of the Wnt-acyl transferase porcupine, and thereby prevents secretion of all Wnt isoforms. We found that inhibiting porcupine dramatically attenuates kidney fibrosis in the murine unilateral ureteral obstruction model. Wnt-C59 treatment similarly blunts collagen mRNA expression in the obstructed kidney. Consistent with its actions to broadly arrest Wnt signaling, porcupine inhibition reduces expression of Wnt target genes and bolsters nuclear exclusion of β-catenin in the kidney following ureteral obstruction. Importantly, prevention of Wnt secretion by Wnt-C59 blunts expression of inflammatory cytokines in the obstructed kidney that otherwise provoke a positive feedback loop of Wnt expression in collagen-producing fibroblasts and epithelial cells. Thus, therapeutic targeting of porcupine abrogates kidney fibrosis not only by overcoming the redundancy of individual Wnt isoforms but also by preventing upstream cytokine-induced Wnt generation. These findings reveal a novel therapeutic maneuver to protect the kidney from fibrosis by interrupting a pathogenic crosstalk loop between locally generated inflammatory cytokines and the Wnt/β-catenin signaling pathway.





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Publication Info

Madan, Babita, Mehul B Patel, Jiandong Zhang, Ralph M Bunte, Nathan P Rudemiller, Robert Griffiths, David M Virshup, Steven D Crowley, et al. (2016). Experimental inhibition of porcupine-mediated Wnt O-acylation attenuates kidney fibrosis. Kidney Int, 89(5). pp. 1062–1074. 10.1016/j.kint.2016.01.017 Retrieved from https://hdl.handle.net/10161/11962.

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Steven Daniel Crowley

Professor of Medicine

Our laboratory explores the contribution of the immune system and inflammatory mediators to the progression of target organ damage in the setting of cardiovascular disease. We are pursuing several related projects in this field:
(1) The actions of type 1 angiotensin receptors on specific immune cell populations in hypertension, target organ damage, and tissue fibrosis.
(2) Cell-specific actions of inflammatory cytokines in regulating blood pressure and end-organ injury.
(3) Mechanism through which dendritic cells regulate renal sodium reabsorption.
(4) The contributions of Wnt O-acylation to kidney scar formation.

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