Tubular β-catenin and FoxO3 interactions protect in chronic kidney disease
Stellor Nlandu-Khodo, … , Ethan Lee, Leslie S. Gewin
Stellor Nlandu-Khodo, … , Ethan Lee, Leslie S. Gewin
Published May 5, 2020
Citation Information: JCI Insight. 2020;5(10):e135454. https://doi.org/10.1172/jci.insight.135454.
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Research Article Cell biology Nephrology

Tubular β-catenin and FoxO3 interactions protect in chronic kidney disease

Abstract

The Wnt/β-catenin signaling pathway plays an important role in renal development and is reexpressed in the injured kidney and other organs. β-Catenin signaling is protective in acute kidney injury (AKI) through actions on the proximal tubule, but the current dogma is that Wnt/β-catenin signaling promotes fibrosis and development of chronic kidney disease (CKD). As the role of proximal tubular β-catenin signaling in CKD remains unclear, we genetically stabilized (i.e., activated) β-catenin specifically in murine proximal tubules. Mice with increased tubular β-catenin signaling were protected in 2 murine models of AKI to CKD progression. Oxidative stress, a common feature of CKD, reduced the conventional T cell factor/lymphoid enhancer factor–dependent β-catenin signaling and augmented FoxO3-dependent activity in proximal tubule cells in vitro and in vivo. The protective effect of proximal tubular β-catenin in renal injury required the presence of FoxO3 in vivo. Furthermore, we identified cystathionine γ-lyase as a potentially novel transcriptional target of β-catenin/FoxO3 interactions in the proximal tubule. Thus, our studies overturned the conventional dogma about β-catenin signaling and CKD by showing a protective effect of proximal tubule β-catenin in CKD and identified a potentially new transcriptional target of β-catenin/FoxO3 signaling that has therapeutic potential for CKD.

Authors

Stellor Nlandu-Khodo, Yosuke Osaki, Lauren Scarfe, Haichun Yang, Melanie Phillips-Mignemi, Jane Tonello, Kenyi Saito-Diaz, Surekha Neelisetty, Alla Ivanova, Tessa Huffstater, Robert McMahon, M. Mark Taketo, Mark deCaestecker, Balakuntalam Kasinath, Raymond C. Harris, Ethan Lee, Leslie S. Gewin

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Figure 6

CSE identified as a potentially novel target of β-catenin and FoxO3 in PT cells.

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CSE identified as a potentially novel target of β-catenin and FoxO3 in P...
(A) RNA-Seq was performed on PT cells transfected with Foxo1, Foxo3, or scramble siRNA, treated with Wnt3a 20 ng/mL and H2O2 100 μM in serum-free medium for 16 hours. (B) Cth, the gene for CSE, was validated as a target for β-catenin and FoxO3 using PT cells. The cells were transfected with Foxo3 or scramble siRNA, then treated with Wnt3a (20 ng/mL) in the presence or absence of oxidative stress (100 μM H2O2 in serum-free medium) for 24 hours, and Cth transcripts were measured by qPCR and normalized to Gapdh (B). *P < 0.05 using the Student’s t test. (C) PT cells were treated ± AA at 30 μM for 7 days with a GSK-3 inhibitor added for the last 2 days, and protein lysates were immunoblotted for CSE with FAK for loading control and quantified using ImageJ (D). PT cells were transfected with either Cth or scramble siRNA and then treated ± AA. (E) Effective reduction in CSE was verified with immunoblots and cleaved caspase-3 measured to detect apoptosis with α-tubulin for loading control. Immunoblots were quantified from 3 independent experiments using ImageJ (F). The statistics for RNA-Seq are discussed in the Methods. For all other comparisons, the Student’s t test comparing 2 sets of data was used (cells without oxidative stress or AA are shown as controls but not included in analyses) with *P < 0.05.