Better Than OK: Enhanced Proximal Tubule Cell Models for Drug Development and Nephrotoxicity Testing

This invention is an optimized cell culture model of kidney proximal tubule cells, created from a subclone of the original opossum kidney cell line, including genetic knockouts for key endocytic proteins. It offers a highly predictive and powerful platform to study proximal tubule function in vitro, making it ideal for identifying direct molecular effects, testing therapies, and assessing nephrotoxicity.

Description

The core of this technology is an optimized subclone of the opossum kidney (OK) cell line, which has been engineered using CRISPR Cas/9 knockout to eliminate the expression of key endocytic uptake proteins, specifically megalin (Lrp2) and Dab2. Unlike other immortalized or primary kidney cell models, this "Better Than OK" cell culture system uniquely largely recapitulates the morphology, ion transport, endocytic capacity, metabolism, and transcriptome of the proximal tubule in vivo. This high degree of physiological relevance makes the model an exceptional biological research tool. It functions as a robust system for identifying the direct effects of molecules on specific proximal tubule functions and for testing therapies aimed at enhancing or preventing protein or drug uptake by the proximal tubule. Furthermore, it is a valuable system for assessing and potentially reducing nephrotoxicity.

Applications

- Pharmaceutical and Biotech Drug Screening: Use in high-throughput screening for new drug candidates and assessing their impact on kidney proximal tubule function.
- Nephrotoxicity Testing: Application in pre-clinical development to evaluate and predict drug-induced kidney damage (nephrotoxicity).
- Toxicology Research: Utilization as a superior in vitro tool for general toxicological studies involving kidney function.
- Custom Cell Line Development: Commercialization of the cell lines (with and without knockouts) as a research reagent for academic and industry labs studying kidney biology.
- Contract Research Organizations (CROs): Offering specialized assays and services based on this model to external clients in need of accurate proximal tubule function data.

Advantages

- Physiologically Relevant Model: The cell culture largely mimics the in vivo morphology, ion transport, metabolism, and transcriptome of the proximal tubule, offering superior predictive power compared to other models.
- Targeted Functional Studies: The genetic knockouts (megalin and Dab2) enable precise studies of endocytic uptake mechanisms and other proximal tubule functions.
- Enhanced Drug Screening: It is a highly useful system for identifying the direct effects of molecules on proximal tubule function.
- Nephrotoxicity Assessment: The model can be used to test therapies to reduce toxicity (nephrotoxicity) from drugs or other agents.
- Therapeutic Testing Platform: Enables testing of therapies designed to enhance or prevent protein or drug uptake by the proximal tubule.

Invention Readiness

The technology is at an early stage of development and in vitro data exists to validate its features and functionality. Further studies would involve expanding the range of applications, validating the model against a wider spectrum of known nephrotoxins, and potentially developing higher-throughput assay formats to facilitate commercial screening applications.

IP Status

Research Tool

Related Publication(s)

Rbaibi, Y., Long, K. R., Shipman, K. E., Ren, Q., Baty, C. J., Kashlan, O. B., & Weisz, O. A. (2023). Megalin, cubilin, and Dab2 drive endocytic flux in kidney proximal tubule cells. Molecular Biology of the Cell, 34(7). https://doi.org/10.1091/mbc.e22-11-0510

Long, K. R., Rbaibi, Y., Bondi, C. D., Ford, B. R., Poholek, A. C., Boyd-Shiwarski, C. R., Tan, R. J., Locker, J. D., & Weisz, O. A. (2022). Cubilin-, megalin-, and Dab2-dependent transcription revealed by CRISPR/Cas9 knockout in kidney proximal tubule cells. American Journal of Physiology-Renal Physiology, 322(1), F14–F26. https://doi.org/10.1152/ajprenal.00259.2021

Ren, Q., Gliozzi, M. L., Rittenhouse, N. L., Edmunds, L. R., Rbaibi, Y., Locker, J. D., Poholek, A. C., Jurczak, M. J., Baty, C. J., & Weisz, O. A. (2019). Shear stress and oxygen availability drive differential changes in opossum kidney proximal tubule cell metabolism and endocytosis. Traffic, 20(6), 448–459. https://doi.org/10.1111/tra.12648

Long, K. R., Shipman, K. E., Rbaibi, Y., Menshikova, E. V., Ritov, V. B., Eshbach, M. L., Jiang, Y., Jackson, E. K., Baty, C. J., & Weisz, O. A. (2017). Proximal tubule apical endocytosis is modulated by fluid shear stress via an mTOR-dependent pathway. Molecular Biology of the Cell, 28(19), 2508–2517. https://doi.org/10.1091/mbc.e17-04-0211