The signaling protein Wnt5a promotes TGFβ1-mediated macrophage polarization and kidney fibrosis by inducing the transcriptional regulators Yap/Taz

Ye Feng,Yan Liang,Xingwen Zhu,Mingjie Wang,Yuan Gui,Qingmiao Lu,Mengru Gu,Xian Xue,Xiaoli Sun,Weichun He,Junwei Yang,Randy L Johnson,Chunsun Dai

doi:10.1074/jbc.ra118.005457

Abstract

M2 macrophage polarization is known to underlie kidney fibrosis. We previously reported that most of the members of the Wnt family of signaling proteins are induced in fibrotic kidneys. Dysregulation of the signaling protein Wnt5a is associated with fibrosis, but little is known about the role of Wnt5a in regulating M2 macrophage activation that results in kidney fibrosis. Here, using murine Raw 264.7 cells and bone marrow-derived macrophages, we found that Wnt5a enhanced transforming growth factor β1 (TGFβ1)-induced macrophage M2 polarization as well as expression of the transcriptional regulators Yes-associated protein (Yap)/transcriptional coactivator with PDZ-binding motif (Taz). Verteporfin blockade of Yap/Taz inhibited both Wnt5a- and TGFβ1-induced macrophage M2 polarization. In mouse models of kidney fibrosis, shRNA-mediated knockdown of Wnt5a expression diminished kidney fibrosis, macrophage Yap/Taz expression, and M2 polarization. Moreover, genetic ablation of Taz in macrophages attenuated kidney fibrosis and macrophage M2 polarization in mice. Collectively, these results indicate that Wnt5a promotes kidney fibrosis by stimulating Yap/Taz-mediated macrophage M2 polarization.

Highlights

M2 macrophage polarization is known to underlie kidney fibrosis
The mRNA abundance for Yes-associated protein (Yap)/transcriptional coactivator with PDZ-binding motif (Taz) target genes, including Ankrd1 and Ctgf, in macrophages was largely elevated from mice injected with pcDNA6.2 but was much less in those from mice injected with Wnt5a short hairpin RNA (shRNA) after UUO or ischemic/reperfusion injury (IRI) (Fig. 6, B and D)
We report that Wnt5a could exacerbate TGF␤1induced macrophage M2 polarization and contribute to kidney fibrosis

Summary

The abbreviations used are

Yes-associated protein; TGF␤1, transforming growth factor ␤1; Taz, transcriptional coactivator with PDZ-binding motif; Tead, TEA domain family member; BMM, bone marrow– derived macrophage; Arg-1, arginase-1; Fizz, found in inflammatory zone 1; MR, mannose receptor; ␣-SMA, ␣-smooth muscle actin; UUO, unilateral ureter obstruction; IRI, ischemic/reperfusion injury; shRNA, short hairpin RNA; qRT-PCR, quantitative RT-PCR; FN, fibronectin; Stat, signal transducer and activator of transcription; p-Stat, phosphorylated Stat; DAPI, 4Ј,6-diamidino-2-phenylindole. Specific ablation of Taz gene in macrophages could markedly inhibit macrophage M2 polarization and kidney fibrosis and in mice

Results

Discussion

Experimental procedures