Pendrin overexpression affects cell volume recovery, intracellular pH and chloride concentration after hypotonicity-induced cell swelling.

Abstract

The pendrin (SLC26A4 or PDS) gene is responsible, when mutated, for the Pendred syndrome, a recessive disorder characterized by sensorineural hearing loss often accompanied by thyroid dysfunctions. Pendrin protein is an anion exchanger and we focused on a still unexplored function that it might play in view of its importance in the inner ear: Cl(-) fluxes regulation during cellular volume control. We challenged HEK-293 Phoenix cells over-expressing wild type pendrin (PDS HEK cells) together with the EYFP (Enhanced Yellow Fluorescent Protein) or over-expressing the EYFP alone (control HEK cells) with hypo-osmolar solutions. Taking advantage of the confocal optical sectioning we measured the cell volume. In addition, we determined the intracellular pH and chloride concentration with fluorescent probes (EYFP and seminaphthorhodafluor-5F, SNARF-5F). Consequently, we could estimate simultaneously Cl(-) fluxes, cellular volume and intracellular pH variations. Cl(-) movements markedly differed between PDS and control HEK cells upon hypotonic shock and are accompanied by an attenuation of the swelling induced pH drop in PDS HEK cells. The contemporary measurements of the three variables not yet reported in living cells, allowed to assess a possible influence of pendrin upregulation in volume homeostasis and evidenced its participation to Cl(-) fluxes.

• Authors: Simona Rodighiero, Guido Bottà, Claudia Bazzini, Giuliano Meyer
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 28 Issue 3 Pg. 559-70 ( 2011) ISSN: 1421-9778 [Electronic] Germany
• PMID: 22116371 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 S. Karger AG, Basel.

Chemical References

• Bacterial Proteins
• Chlorides
• Hypotonic Solutions
• Luminescent Proteins
• Membrane Transport Proteins
• SLC26A4 protein, human
• Sulfate Transporters
• yellow fluorescent protein, Bacteria

Topics

• Bacterial Proteins (genetics, metabolism)
• Cell Line
• Cell Size (drug effects)
• Chlorides (metabolism)
• Gene Expression
• Humans
• Hydrogen-Ion Concentration
• Hypotonic Solutions (pharmacology)
• Luminescent Proteins (genetics, metabolism)
• Membrane Transport Proteins (genetics, metabolism)
• Sulfate Transporters
• Transfection