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Abstract: PO0497

Microenvironmental Influences on 3D Embedded and Bioprinted Induced Renal Tubular Epithelial Cells (iRECs)

Session Information

Category: Bioengineering

  • 300 Bioengineering

Authors

  • Rizzo, Ludovica, Universitat Zurich, Zurich, ZH, Switzerland
  • Tröndle, Kevin, Albert-Ludwigs-Universitat Freiburg Institut fur Mikrosystemtechnik, Freiburg, Baden-Württemberg, Germany
  • Bühler, Michaela, Universitatsklinikum Freiburg Abteilung Innere Medizin IV Nephrologie und Allgemeinmedizin, Freiburg, Baden-Württemberg, Germany
  • Pichler, Roman, Universitatsklinikum Freiburg Abteilung Innere Medizin IV Nephrologie und Allgemeinmedizin, Freiburg, Baden-Württemberg, Germany
  • Lienkamp, Soeren S., Universitat Zurich, Zurich, ZH, Switzerland
Background

Conventional cellular models of renal tubular origin only partially maintain their functional properties. Recent advances in 3D culture techniques and bioprinting technology promise to improve physiological conditions by reconstituting the tissue architecture in vitro. We previously described that direct reprogramming with a defined lentiviral cocktail of four transcription factors (Hnf1b, Hnf4a, Pax8, Emx2) can convert fibroblasts to induced renal tubular epithelial cells (iRECs). We analyzed how the microenvironment influences behavior, expression profile and the cellular function of iRECs to determine their utility for bioprinting applications.

Methods

iRECs were subjected to manual pipetting and inkjet bioprinting methods, embedded in three ECM-like microenvironments (Matrigel, Fibrin and Collagen I), and two culture media (DMEM and REGM). Morphology and viability of multicellular structures were assessed at several time points after seeding. Moreover, RNA-Seq was carried out to describe differentially regulated genes, and their protein products analyzed via immunofluorescence.

Results

iRECs showed high viability and biocompatibility with dispensing methods and bioinks. However, the morphology of multicellular aggregates was dramatically influenced by the microenvironment (e.g. they formed smaller spherical aggregates in Matrigel, but elongated tubule-like structures in Collagen I). Transcriptomic analysis revealed differentially expressed signature genes in each of the used biomaterials. For example, expression of apical endocytic machinery components was elevated in Matrigel embedded cells. In contrast, transcripts of ECM components showed strongest expression in the Fibrin condition. In addition, the tubule segment identity of iRECs was altered by the microenvironment. Microdispensing (drop on demand) bioprinting achieved perfusable tubule-like structures.

Conclusion

The design of specific tubule microenvironments for reprogrammed kidney tubule cells can be tailored to better reflect physiological conditions and to the desired purpose of vitro applications. This will facilitate the use of appropriate biomaterials to optimize the construction of biomimetic kidney tubule models at scale.

Funding

  • Government Support – Non-U.S.