Abstract: SA-PO484
Fibrocystin Is Central to Cellular Control of Adhesion Forces and Epithelial Polarity
Session Information
- Cystic Kidney Diseases: Basic/Translational
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1001 Genetic Diseases of the Kidneys: Cystic
Authors
- Ziegler, Wolfgang H., Hannover Medical School, Hannover, Germany
- Soetje, Birga, Hannover Medical School, Hannover, Germany
- Marten, Lisa P., Hannover Medical School, Hannover, Germany
- Hassan, Fatima, Hannover Medical School, Hannover, Germany
- Haffner, Dieter, Hannover Medical School, Hannover, Germany
Background
Mutations of the Pkhd1 gene cause autosomal recessive polycystic kidney disease (ARPKD). Pkhd1 encodes fibrocystin/polyductin (FPC), a ciliary type I membrane protein of largely uncharacterized function, suggested to affect adhesion signaling of cells. Contributions of altered epithelial cell adhesion and contractility to the disease process of ARPKD are elusive. Here, we study how loss of FPC (function) modifies epithelial cell response to adhesion stimuli and contractile force distribution leading to defective control of epithelial polarity.
Methods
To address FPC function in cells with renal collecting duct characteristics, we study Pkhd1-silenced Madin-Darby canine kidney cells (MDCKII) and human urine-derived renal epithelial cells (UREC) with normal and defective FPC. Consequences of FPC-deficiency are addressed by proteomics analysis and in cells studied in 2D/3D cell culture conditions, which includes micro-pattered chips and allows analysis of polarity, lumen formation and ciliogenesis in epithelial spheroids. Adhesion forces are studied via RhoA activation and myosin IIa phosphorylation and linked to adhesion signaling.
Results
FPC-mediated changes in epithelial cell characteristics, as revealed in proteomics-based pathway analysis, are linked to altered adhesion behavior and cellular capacity to form polarized epithelia. Their impact can be confirmed using selective inhibitors of cell contractility and FAK/Src signaling. FPC-deficient cells are characterized by defects in the formation of correctly polarized epithelial spheroids, which is restored upon transient reduction of cell contractility and adhesion forces during the initial phase of epithelial morphogenesis.
Conclusion
In FPC-deficient epithelial cells, altered control of pathway activity leads to enhanced integrin adhesion signals, impaired epithelial morphogenesis and by implication homeostasis, which are presumably related to progressive epithelial defects in ARPKD. Epithelial cell-based models with selective genetic alterations allow a better molecular understanding and furthermore may provide means to test pharmacological correction of epithelial defects in PKD.
Funding
- Private Foundation Support