title: Identification of two-pore domain potassium channels as potent modulators of osmotic volume regulation in human T lymphocytes.
abstract: Many functions of T lymphocytes are closely related to cell volume homeostasis and regulation, which utilize a complex network of membrane channels for anions and cations. Among the various potassium channels, the voltage-gated K(V)1.3 is well known to contribute greatly to the osmoregulation and particularly to the potassium release during the regulatory volume decrease (RVD) of T cells faced with hypotonic environment. Here we address a putative role of the newly identified two-pore domain (K(2P)) channels in the RVD of human CD4(+) T lymphocytes, using a series of potent well known channel blockers. In the present study, the pharmacological profiles of RVD inhibition revealed K(2P)5.1 and K(2P)18.1 as the most important K(2P) channels involved in the RVD of both naïve and stimulated T cells. The impact of chemical inhibition of K(2P)5.1 and K(2P)18.1 on the RVD was comparable to that of K(V)1.3. K(2P)9.1 also notably contributed to the RVD of T cells but the extent of this contribution and its dependence on the activation status could not be unambiguously resolved. In summary, our data provide first evidence that the RVD-related potassium efflux from human T lymphocytes relies on K(2P) channels.
authors.affiliation: University of Wuerzburg, Lehrstuhl für Biotechnologie und Biophysik, Biozentrum, Am Hubland, 97074 Wuerzburg, Germany.
authors.forename: Joseph
authors.initials: J
authors.lastname: Andronic
authors.forename: Nicole
authors.initials: N
authors.lastname: Bobak
authors.forename: Stefan
authors.initials: S
authors.lastname: Bittner
authors.forename: Petra
authors.initials: P
authors.lastname: Ehling
authors.forename: Christoph
authors.initials: C
authors.lastname: Kleinschnitz
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Herrmann
authors.forename: Heiko
authors.initials: H
authors.lastname: Zimmermann
authors.forename: Markus
authors.initials: M
authors.lastname: Sauer
authors.forename: Heinz
authors.initials: H
authors.lastname: Wiendl
authors.forename: Thomas
authors.initials: T
authors.lastname: Budde
authors.forename: Sven G
authors.initials: SG
authors.lastname: Meuth
authors.forename: Vladimir L
authors.initials: VL
authors.lastname: Sukhorukov
mesh_terms: D001703:Biophysics / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D004594:Electrophysiology / Q000379:methods; D006706:Homeostasis; D006801:Humans; D007249:Inflammation; D007477:Ions; D018715:Microscopy, Video / Q000379:methods; D009995:Osmosis; D024683:Potassium Channels, Tandem Pore Domain / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D013997:Time Factors
chemical_list: D007477:Ions; D024683:Potassium Channels, Tandem Pore Domain; D011948:Receptors, Antigen, T-Cell