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Abstract: SA-PO305

Colocalization of Claudin-10 with Other Transport Proteins in Basolateral Infoldings of the Thick Ascending Limb

Session Information

Category: Fluid and Electrolytes

  • 901 Fluid and Electrolytes: Basic

Authors

  • Quintanova, Catarina, Christian-Albrechts-University Kiel, Kiel, Germany
  • Svendsen, Samuel L.C., Aarhus University, Aarhus C, Denmark
  • Von schwerdtner, Otto, Christian-Albrechts-University Kiel, Kiel, Germany
  • Merkel, Cosima, Christian-Albrechts-University Kiel, Kiel, Germany
  • Breiderhoff, Tilman, Charite University Berlin, Berlin, Germany
  • Müller, Dominik, Charite University Berlin, Berlin, Germany
  • Himmerkus, Nina, Christian-Albrechts-University Kiel, Kiel, Germany
  • Günzel, Dorothee, Charite University Berlin, Berlin, Germany
  • Bleich, Markus, Christian-Albrechts-University Kiel, Kiel, Germany
Background

The nephron is the structural and functional unit of the kidney and is composed of renal tubular segments. The thick ascending limb (TAL) of the loop of Henle is the essential segment for salt homeostasis and urinary concentration. The TAL originates from medullary and cortical nephron and share the basic transcellular transport mechanism that involve cotransport of sodium (Na+), potassium (K+) and chloride (Cl-) and paracellular cation permeability. The selectivity of the paracellular pathway is determined by the combination of claudin protein expression in the tight junctions (TJ). In the TAL, TJs showed a mosaic expression of either claudin-10 or claudin-3/claudin-16/claudin-19 in a complex. TJ dominated by claudin-10 confer mainly paracellular Na+ permeability. Interestingly, claudin-10 immunofluorescence showed also an extra-junctional localization in the basolateral region of the cells.

Methods

Freshly isolated single murine TAL segments of C57Bl6 and kidney specific (Ksp-Cre) Claudin-10 knockout mice were investigated by immunofluorescence and analyzed by stimulated emission depletion (STED) and Airyscan confocal microscopy.

Results

We performed triple staining with claudin-10, Na+/K+-ATPase (NKA) and the chloride channel subunit Barttin, which are both known to be prominent proteins in the basolateral TAL membrane. Antibody staining revealed the localization of all proteins in the infoldings of the basolateral membrane. Claudin-10 thereby showed a dotted pattern.

Conclusion

Claudin-10 shows extra-junctional expression and colocalization together with tramsmebrane transport proteins NKA and Barttin in the basolateral infoldings of TAL. This suggests a functional complex that facilitates or regulates ion transport function.