Kidney Week

Abstract: TH-OR104

Role of the Mechanosensitive Ion Channel Piezo1 in Autosomal Dominant Polycystic Kidney Disease

Session Information

• PKD: Genetic, Mechanistic, and Clinical
  October 25, 2018 | Location: 25A, San Diego Convention Center
  Abstract Time: 05:06 PM - 05:18 PM

Category: Genetic Diseases of the Kidney

• 1001 Genetic Diseases of the Kidney: Cystic

Authors

• Chebib, Fouad T., Mayo Clinic , Rochester, Minnesota, United States

Fouad T. Chebib, MD, FASN

• Irazabal, Maria V., Mayo Clinic, Rochester, Minnesota, United States

Maria V. Irazabal,

• Torres, Vicente E., Mayo Clinic , Rochester, Minnesota, United States

Vicente E. Torres,

Background

Disruption of intracellular calcium (iCa²⁺) likely underlies the upregulation of cAMP signaling and the proliferative and secretory phenotype of the cystic epithelium in ADPKD. However, the mechanisms by which polycystins reduce iCa²⁺ remain elusive. Impaired flow-induced Ca²⁺ entry through ciliary polycystin complex has been previously proposed as a pathogenic mechanism, but newer evidence suggests the involvement of polycystins in modulation of other mechanosensitive ion channels such as Piezo1, the novel stretch-activated cation channel. We hypothesized that polycystins, through their physical and functional interaction with Piezo1, modulate various cellular responses to mechanical stimulation.

Methods

Wild type inner medullary collecting duct cells (mIMCD3) were stably transfected with genetically encoded biosensors, jRGeco1a and Flamindo2, to study spatiotemporal dynamics of Ca²⁺ and cAMP during live cell imaging, respectively. These cells were also cultured in 3D matrigel matrix. Metanephric embryonic kindeys were cultured and stimualted with forskolin.

Results

Piezo1 is expressed in both WT mIMCD3 cells and PKD₂ null cells (~3 fold higher than wild type). Piezo1 activation by Yoda1 increased cytoplasmic calcium and simultaneously lowered forskolin-induced cAMP (Figure 1A). Additionally, exerting physiological fluid shear stress (FSS) (ibidi pump system) led to reduction in cAMP (Figure 1B). Yoda1 significantly reduced forskolin-induced in vitro cystogenesis by 68% in WT and by 48% in PKD₂ null mIMCD3 cells (Figure1C). Low dose Yoda1 (750nM) prevented cyst formation in forskolin-induced cystogenesis of metanephric organ culture (Figure1D).

Conclusion

Piezo1 activation inhibits cystogenesis in matrigel matrices and metanephric organ cultures. Further studies are required to determine in vivo effect of Piezo1 on renal cystogenesis.