1. Academic Validation
  2. Involvement of aquaporins in Shiga toxin-induced swelling and water transport dysfunction in human renal microvascular endothelial cells

Involvement of aquaporins in Shiga toxin-induced swelling and water transport dysfunction in human renal microvascular endothelial cells

  • Biochim Biophys Acta Mol Cell Res. 2024 Oct 21;1872(1):119866. doi: 10.1016/j.bbamcr.2024.119866.
Fernando D Gomez 1 Julieta Reppetti 2 Romina S Alvarez 1 Daniel C Girón Reyes 1 Flavia Sacerdoti 1 Alejandro Balestracci 3 Alicia E Damiano 4 Nora A Martínez 2 Gisela Di Giusto 5 María M Amaral 6
Affiliations

Affiliations

  • 1 Universidad de Buenos Aires, Facultad de Ciencias Médicas, Departamento de Ciencias Fisiológicas, Laboratorio de Fisiopatogenia, Buenos Aires C1121ABG, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Buenos Aires C1121ABG, Argentina.
  • 2 CONICET - Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Buenos Aires C1121ABG, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Médicas, Laboratorio de Biología de la Reproducción, Buenos Aires C1121ABG, Argentina.
  • 3 Unidad de Nefrología, Hospital General de Niños Pedro de Elizalde, Buenos Aires C1270AAN, Argentina.
  • 4 CONICET - Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Buenos Aires C1121ABG, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Médicas, Laboratorio de Biología de la Reproducción, Buenos Aires C1121ABG, Argentina; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Biología Celular y Molecular, Buenos Aires C1113AAD, Argentina.
  • 5 CONICET - Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Buenos Aires C1121ABG, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Médicas, Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas, Buenos Aires C1121ABG, Argentina.
  • 6 Universidad de Buenos Aires, Facultad de Ciencias Médicas, Departamento de Ciencias Fisiológicas, Laboratorio de Fisiopatogenia, Buenos Aires C1121ABG, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Buenos Aires C1121ABG, Argentina. Electronic address: mamaral@fmed.uba.ar.
Abstract

One of the hallmarks of Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is kidney damage. Our previous research demonstrated that Shiga toxin type 2 (Stx2a) decreases cell viability and induces swelling of human glomerular endothelial cells (HGEC). However, Stx2a can disrupt net water transport across HGEC monolayers without affecting cell viability. This work aimed to elucidate the possible mechanisms involved in the water transport disruption caused by Stx2a across HGEC monolayers. We investigated paracellular and transcellular water transfer across HGEC by analyzing the passage of FITC-Dextran and the hydrostatic pressure (Phydr) and measuring the osmotic pressure (Posm), respectively. Stx2a selectively affected the transcellular pathway without impacting the paracellular route. Furthermore, Stx2a cell swelling was prevented by pretreatment with Aquaporin inhibitors tetraethylammonium chloride (TEA), Mercury (II) chloride (HgCl2) or TGN-020, suggesting Aquaporin involvement in this process. Confocal microscopy revealed that Stx2a increased HGEC total volume, which TEA and TGN-020 counteracted. Additionally, we identified in HGEC not only the expression of aquaporin-1 (AQP1) but also the expression of aquaporin-4 (AQP4). Surprisingly, we observed a decrease in the expression of both AQPs after Stx2a exposure. Our findings suggest that Stx2a may induce water movement into HGEC via AQP1 and AQP4, increasing total cell volume. Subsequently, decreased AQP1 and AQP4 expression could inhibit transcellular water transfer, potentially as a protective mechanism against excessive water entry and Cell Lysis.

Keywords

Hemolytic uremic syndrome; Human glomerular endothelial cells, aquaporins; Shiga toxin type 2.

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