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Abstract: FR-PO387

A New Quantifiable View of the Renin Cell Niche in Longitudinal 3D Intravital Microscopy Reveals a Response to Glomerular Injury Feedback System

Session Information

Category: Development‚ Stem Cells‚ and Regenerative Medicine

  • 500 Development‚ Stem Cells‚ and Regenerative Medicine

Authors

  • Arndt, Patrick, Universitatsklinikum Carl Gustav Carus, Dresden, Germany
  • Sradnick, Jan, Universitatsklinikum Carl Gustav Carus, Dresden, Germany
  • Kroeger, Hannah, Universitatsklinikum Carl Gustav Carus, Dresden, Germany
  • Holtzhausen, Stefan, Technische Universitat Dresden, Dresden, Germany
  • Gerlach, Michael, Universitatsklinikum Carl Gustav Carus, Dresden, Germany
  • Todorov, Vladimir T., Universitatsklinikum Carl Gustav Carus, Dresden, Germany
  • Hugo, Christian, Universitatsklinikum Carl Gustav Carus, Dresden, Germany
Background

Renin cells (RC) reside in the juxtaglomerular apparatus and function as progenitors capable of migrating into the glomerulus after injury. While regulation of these repair processes is poorly understood, the authors propose the hypothesis that glomerular repair processes in adults underlie an individual intraglomerular-juxtaglomerular feedback mechanism. Using longitudinal intravital microscopy and a laser injury model that induces local damage in individual glomeruli, enables controlled observations of repair processes. Using virtual ray tracing, an optical object characterization technique, a new method of quantification in longitudinal 3D intravital imaging, especially a detailed characterization of the renin cell niche, was established.

Methods

Renin reporter mice underwent doxycycline pulse induction. Intravital microscopy was performed through an implanted body window under an upright Leica SP8 LSM for 3 hours on up to 7 days. Laser injury was induced by focusing 100% laser power for 5 seconds at 48x zoom on one Z-plane. 3D processing was performed with Bitplane Imaris 9.7 and novel 3D image quantification was realized by the Marching Cubes algorithm. The calculation of the directional thickness of RC was based on an adapted ray tracing method.

Results

Targeted use of laser irradiation established an inducible, selective and reproducible intraglomerular injury model. Migrating RC extended during 3 hours towards the injury area, infiltrating this areas vicinity without losing contact to the juxtaglomerular RC. During these processes the RC volume first increased outside the glomerulus and then showed an up to threefold increased area of dynamic migration with up to 344% compared to their niche of origin.

Conclusion

Longitudinal intravital microscopy combined with laser-induced intraglomerular injury and 3D image analysis of injury directed renin cell migration in transgenic mice was assessed in a quantifiable manner. The combination of these technologies provides a new powerful tool for studying the juxtaglomerular feedback system of renin cell recruitment/migration and transdifferentiation as a site-specific response to intraglomerular injury and may promise viable targets for further glomerular research.