ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: PO0300

May the (Mechanical) Force Be with You: Modeling Shear Stress on the Glomerulus-On-a-Chip

Session Information

  • Bioengineering
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Bioengineering

  • 300 Bioengineering

Authors

  • Da Sacco, Stefano, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Richfield, Owen, Tulane University, New Orleans, Louisiana, United States
  • Villani, Valentina, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Clair, Geremy, Pacific Northwest National Laboratory, Richland, Washington, United States
  • De Filippo, Roger E., Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Perin, Laura, Children's Hospital of Los Angeles, Los Angeles, California, United States
Background

In the glomerulus, mechanical forces generated on glomerular endothelial cells (GEC) by the passage of blood in capillaries and by the flow of ultrafiltrate between adjacent podocytes play a critical role in regulating glomerular filtration. In vivo modeling of shear stress is difficult and traditional in vitro 2D systems are unable to faithfully replicate shear and tensile stress. We have recently developed a barrier-free glomerulus-on-a-chip (GOAC) system that closely mimics architecture, physiology and function of the GFB. In this work we have further modeled shear stress on the chip and assessed how changes in mechanical forces affect the barrier formation and function.

Methods

Mathematical modeling of the shear stress on the GOAC was performed and shear stress was calculated for standard GOAC culture conditions. Using model simulations, angle of inclination and rocking frequency of the GOAC were changed to modify shear stress, and results were assessed after 5 days. Phenotypical analysis by IF were performed and function was measured by albumin-leakage assay. Podocytes and GEC were separated by FACS and transcriptomics and proteomics analysis performed.

Results

Under standard culture conditions, time-averaged shear stress generated by rocking the GOAC is equal to 0.1Pa. By changing angle of the rocking platform, shear stress could be modulated from 0 to ~4Pa exerted on the GEC with each rocking motion. Permselectivity was not significantly affected by different rocking angles (but was impaired under static conditions) after 5 days. Importantly, Gene and protein expression analysis on podocytes and GEC have identified important changes in cytoskeleton regulation, ECM-cell interaction, proliferation and transcription factors, suggesting that longer-term modification of the shear stress might significantly impact phenotypical and functional cell activity.

Conclusion

The glomerulus-on-a-chip is an ideal system to model architecture and function of the glomerular filtration barrier, including mechanical forces. Changes in shear stress affect cellular gene and protein expression in the GFB and can have long-term effects on phenotype and function. The glomerulus-on-a-chip system can provide an important in vitro tool to study the role of shear stress in physiological and pathological conditions.

Funding

  • NIDDK Support