DDR1 contributes to kidney inflammation and fibrosis by promoting the phosphorylation of BCR and STAT3
Corina M. Borza, … , Roy Zent, Ambra Pozzi
Corina M. Borza, … , Roy Zent, Ambra Pozzi
Published December 23, 2021
Citation Information: JCI Insight. 2022;7(3):e150887. https://doi.org/10.1172/jci.insight.150887.
View: Text | PDF
Research Article Cell biology Nephrology

DDR1 contributes to kidney inflammation and fibrosis by promoting the phosphorylation of BCR and STAT3

Abstract

Discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase activated by collagen, contributes to chronic kidney disease. However, its role in acute kidney injury and subsequent development of kidney fibrosis is not clear. Thus, we performed a model of severe ischemia/reperfusion-induced acute kidney injury that progressed to kidney fibrosis in WT and Ddr1-null mice. We showed that Ddr1-null mice had reduced acute tubular injury, inflammation, and tubulointerstitial fibrosis with overall decreased renal monocyte chemoattractant protein (MCP-1) levels and STAT3 activation. We identified breakpoint cluster region (BCR) protein as a phosphorylated target of DDR1 that controls MCP-1 production in renal proximal tubule epithelial cells. DDR1-induced BCR phosphorylation or BCR downregulation increased MCP-1 secretion, suggesting that BCR negatively regulates the levels of MCP-1. Mechanistically, phosphorylation or downregulation of BCR increased β-catenin activity and in turn MCP-1 production. Finally, we showed that DDR1-mediated STAT3 activation was required to stimulate the secretion of TGF-β. Thus, DDR1 contributes to acute and chronic kidney injury by regulating BCR and STAT3 phosphorylation and in turn the production of MCP-1 and TGF-β. These findings identify DDR1 an attractive therapeutic target for ameliorating both proinflammatory and profibrotic signaling in kidney disease.

Authors

Corina M. Borza, Gema Bolas, Fabian Bock, Xiuqi Zhang, Favour C. Akabogu, Ming-Zhi Zhang, Mark de Caestecker, Min Yang, Haichun Yang, Ethan Lee, Leslie Gewin, Agnes B. Fogo, W. Hayes McDonald, Roy Zent, Ambra Pozzi

×

Figure 5

DDR1 promotes BCR phosphorylation in vivo and in vitro.

Options: View larger image (or click on image) Download as PowerPoint
DDR1 promotes BCR phosphorylation in vivo and in vitro. (A) Vector- or D...
(A) Vector- or DDR1-HEK cells were treated with collagen I (50 μg/mL) or vehicle, then lysed and immunoprecipitated with anti-Flag antibody, and analyzed for levels of total and phosphorylated DDR1 or BCR. (B) DDR1-HEK or DDR1-K655A-HEK cells were treated with collagen I (50 μg/mL), and the cell lysates were analyzed for levels of total and phosphorylated DDR1 or BCR. (C) RPTECs were treated with collagen I (50 μg/mL) ± Cmp-1 as indicated and then analyzed as described in B. The black vertical line separates 2 gels that were run and developed at the same time. (D) pBCR and BCR bands in C were quantified by densitometry, and the pBCR level is expressed as pBCR/BCR ratio. Dara shown are mean ± SD of 1 experiment performed in triplicate (n = 3 experiments). Statistical analysis: 1-way ANOVA followed by Dunnett’s multiple-comparison test versus untreated cells for pBCR and 2-way ANOVA followed by Sidak’s multiple-comparison test for Cmp-1–treated versus untreated cells. (E) Primary RPTECs isolated from WT (WT-mRPTECs) and Ddr1-KO (Ddr1-KO-mRPTECs) mice were treated with vehicle or collagen I (50 μg/mL) for 30 minutes and then analyzed as described above. (F) pBCR and BCR bands were quantified using the software provided by Odyssey CLx imaging system. Circles represent cells isolated from a single mouse and values represent mean ± SD n = 5 mice for each group. Statistical analysis: 1-way ANOVA followed by Tukey’s multiple-comparison test. (G) Kidney cortices from uninjured (d–1), d1, and d3 injured WT and Ddr1-KO mice were analyzed by Western blot for the levels of pBCR and BCR. (H) pBCR and BCR bands at d3 were quantified by densitometry, and pBCR is expressed as pBCR/BCR ratio. Circles represent individual kidneys, values represent mean ± SD, WT n = 10, Ddr1-KO n = 8. Statistical analysis: 2-tailed t test.