Kidney Week

Abstract: SA-OR57

Intranephron Cross-Talk through Exosomes

Session Information

• Glomerular Diseases: All about Podocytes
  October 26, 2024 | Location: Room 1, Convention Center
  Abstract Time: 04:50 PM - 05:00 PM

Category: Glomerular Diseases

• 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

• Kern, Janina, Universitatsklinikum Erlangen Medizinische Klinik 4 Nephrologie und Hypertensiologie, Erlangen, Bayern, Germany

Janina Kern, MS, MSc

• Thiagarajan, Sindhu, Universitatsklinikum Erlangen Medizinische Klinik 4 Nephrologie und Hypertensiologie, Erlangen, Bayern, Germany

Sindhu Thiagarajan, MSc

• Uderhardt, Stefan, Universitatsklinikum Erlangen Medizinische Klinik 3 Rheumatologie und Immunologie, Erlangen, Bayern, Germany

Stefan Uderhardt, DrMed

• Sopel, Nina, Universitatsklinikum Erlangen Medizinische Klinik 4 Nephrologie und Hypertensiologie, Erlangen, Bayern, Germany

Nina Sopel, PhD

• Schiffer, Mario, Universitatsklinikum Erlangen Medizinische Klinik 4 Nephrologie und Hypertensiologie, Erlangen, Bayern, Germany

Mario Schiffer, MD, DrMed, MBA

• Müller-Deile, Janina, Universitatsklinikum Erlangen Medizinische Klinik 4 Nephrologie und Hypertensiologie, Erlangen, Bayern, Germany

Janina Müller-Deile, MD, DrMed

Background

Insufficient cell-cell communication of glomerular endothelial cells (GECs) and podocytes leads to a dysfunctional glomerular filtration barrier and not much is known about the intra-glomerular as well as the glomerular to tubular signaling. Exosomes are 30 nm to 160 nm small extracellular vesicles released by multivesicular bodies from various cell types. These transport vehicles encapsulate signaling molecules such as mRNAs, microRNAs or proteins. Exosomes secreted from cells acing the urinary space might be taken up by tubular cells. However, it is unclear if exosomes can serve as mediators of GEC to podocyte crosstalk in vivo as it is unknown if they are able to pass the glomerular basement membrane (GBM).

Methods

RNA seq analysis and proteomics were used to characterize exosome cargo of glomerular cells. A CD63 (surface protein of exosomes) plasmid tagged with mScarlet and pHluorin (labeling intracellular exosomes in red and secreted exosomes in green) was used to investigate exosome secretion in glomerular cell culture models. By injecting zebrafish eggs in one cell stadium with a pHluorin CD63 reporter plasmid including one with a podocin promotor for podocyte specific exosome labeling, exosomes could be visualized in zebrafish larvae with a multiphoton microscope in high resolution. Moreover, in vitro labeled exosomes were injected in the zebrafish circulation and visualized with immunofluorescence and electron microscopy, to examine their ability to pass the GBM.

Results

In vitro podocytes and GECs secreted exosomes that could be live-tracked with the help of a spinning disc microscope. Live tracking analyses in 2D and 3D glomerular co-culture detected exosome-transfer from one cell type to another. Incubation of GECs derived exosomes changed expression in podocytes and likewise podocyte derived exosomes had effects on tubular cell expression. Injecting fluorescently labeled exosomes into the zebrafish circulation allowed to study the permeability of exosomes for the GBM. Using CD63 plasmids encoding podocyte-specific labeled exosomes helped to investigate cell-cell communication via exosomes originated from podocytes.

Conclusion

Live tracking experiments of glomerular cell type derived exosomes will help to get more insights into inter-glomerular and glomerular to tubular cell-cell communication.

Funding

• Government Support – Non-U.S.