Abstract: SA-PO117
β-Catenin/Foxo Promotes Epithelial Healing in Kidney Injury
Session Information
- AKI: Mechanisms - AKI-CKD Transition
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Rao, Padmashree, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Qiao, Xi, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Yu, Hong, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Chen, Titi, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Cao, Qi, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Wang, Yiping, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Lee, Vincent W.S., The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Wang, Yuan Min, Children's Hospital at Westmead. The University of Sydney, Westmead, New South Wales, Australia
- Alexander, Stephen I., Children's Hospital at Westmead. The University of Sydney, Westmead, New South Wales, Australia
- Zheng, Guoping, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Harris, David, The University of Sydney at The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
Background
Transforming growth factor (TGF-β) is known to promote healing after tissue injury, but also drives a maladaptive fibrotic response that leads to fibrosis and organ failure. β-catenin/TCF is central to TGF-β’s profibrotic signaling pathways. β-catenin also binds to Foxo in competition with TCF and promote cell survival under oxidative stress. We propose that targeting TGF-β signaling by using an inhibitor of β-catenin/TCF will promote β-catenin/Foxo which results in physiological healing with epithelial rather than mesenchymal cells.
Methods
Scratch assay was used as an in vitro model of healing in murine proximal tubule-like epithelial C1.1 cells treated with TGF-β1 (3ng/ml) with or without β-catenin/TCF inhibitor ICG-001 (5µM). CRISPR/Cas9 was used to knockout Foxo1. Wound closure was measured as the percentage area of wound closure at 48 h (%). In vivo kidney injury healing was evaluated in murine unilateral ischemia reperfusion injury (UIR) by Gomori trichrome staining. Epithelial (E-cadherin) or mesenchymal (α-SMA) healing was examined by immunofluorescence staining and measured as percentage area of positive staining (%). β-catenin/Foxo or β-catenin/TCF interactions were examined by proximity ligation assay (PLA).
Results
The combined treatment of TGF-β1 and ICG-001 in C1.1 cells and UIR caused increased β-catenin/Foxo interaction as demonstrated by PLA. The combined treatment inhibited TGF-β-induced α-SMA expression and showed dominant E-cadherin expression to a greater extent than seen with TGF-β alone; α-SMA, 5±1% vs 40±3%, P<0.01 in vitro, and 18±1% vs 42±3%, P<0.01 in vivo; E-cadherin, 29±4% vs 2±3%, P<0.05 in vitro, and 22±5% vs 11±2%, P<0.05 in vivo. Foxo1 KO in C1.1 cells showed significant reduction in closure of the wound gap compared to WT cells (75±3% vs 95±3%; P<0.05). Foxo1 KO C1.1 cells slowed wound closure under combined treatment compared to that of WT cells (70±3% vs 98±2%, P<0.01) which could be explained by absence of β-catenin/Foxo in Foxo1 KO C1.1 cells. In UIR mice, combined treatment with rhTGF-β and ICG-001 significantly attenuated kidney fibrosis compared with TGF-β alone (42±5% vs 73±5%, P<0.01).
Conclusion
These results indicate that β-catenin/Foxo may serve as a therapeutic target to prevent pathological fibrotic healing and fibrosis in the treatment of kidney diseases.