Abstract: FR-PO972
Major Vault Protein Contributes to Tubulointerstitial Inflammation and Fibrosis Through PI3K/AKT Signaling in a Murine Model of CKD
Session Information
- CKD: Pathobiology - I
November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2203 CKD (Non-Dialysis): Mechanisms
Authors
- Wong, Cheuk Yin, The University of Hong Kong, Hong Kong, Hong Kong
- Yung, Susan, The University of Hong Kong, Hong Kong, Hong Kong
- Chan, Caleb C. Y., The University of Hong Kong, Hong Kong, Hong Kong
- Chan, Tak Mao Daniel, The University of Hong Kong, Hong Kong, Hong Kong
Background
Chronic kidney disease (CKD) is characterized by progressive tubulointerstitial fibrosis and tubular atrophy, influx of immune cells, and progression to kidney failure. We previously demonstrated that major vault protein (MVP), a key component of the vault complex, was increased in proximal renal tubular epithelial cells (PTEC) in CKD patients. We further investigated the role of MVP in tubulointerstitial inflammation and fibrosis.
Methods
CKD was induced in wild-type (WT) and MVP-knockout (KO) mice by feeding with casein-based chow containing 0.2% adenine for 8 weeks; and mice fed casein-based chow served as non-CKD control. Mice were sacrificed and renal cortical tissue harvested for qPCR, immunohistochemistry, and flow cytometry analysis. MVP-deficient HK-2 cells were generated using CRISPR/Cas 9; and non-transfected cells served as control.
Results
WT mice with CKD showed increased MVP expression in PTEC compared to control WT mice without CKD. WT mice with CKD showed marked tubular atrophy, macrophage infiltration, and increased expression of pro-inflammatory and pro-fibrotic mediators comprising CCL2, CCR2, CCL5, CCR5, TNF-a, IL-6, VCAM-1, alpha-smooth muscle actin, vimentin, fibronectin, and collagen. Increased CD45+ immune cells and F4/80+/ CD11b+ macrophages were shown with flow cytometry. In MVP KO mice with CKD the histopathological abnormalities were less severe, with reduced expression of pro-inflammatory and pro-fibrotic mediators and decreased AKT phosphorylation. Exogenous TNF-a increased MVP expression and CCL2 secretion in non-transfected HK-2 cells, mediated in part through increased PI3K/AKT phosphorylation. In contrast, MVP-deficient HK-2 cells showed significantly less AKT phosphorylation and CCL2 secretion upon exposure to TNF-a.
Conclusion
Our data suggest that MVP contributes to the pathogenesis of renal tubulointerstitial inflammation and fibrosis in CKD through increased PI3K/AKT phosphorylation.
Funding
- Government Support – Non-U.S.