Membrane potential modulates release of tumor necrosis factor in lipopolysaccharide-stimulated mouse macrophages

Autor(en)

A Haslberger, C Romanin, R Koerber

Abstrakt

Lipopolysaccharide (LPS)-mediated synthesis of macrophage gene products such as tumor necrosis factor (TNF) is controlled by different signaling pathways. We investigated intracellular free Ca2+ (Ca2+ic) and the membrane potential as early cellular responses to LPS and their role in the synthesis and release of TNF. In peritoneal macrophages and in the RAW 269 mouse macrophage cell line, LPS and its biologically active moiety lipid A stimulated TNF synthesis but exerted no significant effects on these early cellular responses using Fura-2/Indo-1 to measure Ca2+ic and bis-oxonol, as well as the patch-clamp technique to monitor membrane potential. In contrast, the platelet-activating factor transiently induced both an increase in Ca2+ic and cell membrane depolarization but no significant TNF release. Increased extracellular K+ concentrations or K(+)-channel blockers, such as quinine, tetraethylammonium, or barium chloride, inhibited the LPS-stimulated release of TNF alpha, as well as the accumulation of cell-associated TNF alpha as found by enzyme-linked immunosorbent assay analysis, but did not inhibit TNF alpha mRNA accumulation. Concentrations of quinine (greater than 125 microM) or of enhanced extracellular K+ (25-85 mM) required to inhibit TNF production both significantly depolarized macrophages. These results indicate a lack of ion transport activities as early cellular responses of macrophages to LPS but suggest an important regulatory role of the membrane potential on the posttranscriptional synthesis and release of TNF in macrophages.

Organisation(en)

Department für Ernährungswissenschaften, Department für Strukturbiologie und Computational Biology

Journal

Molecular Biology of the Cell

Band

3

Seiten

451-60

Anzahl der Seiten

10

ISSN

1059-1524

Publikationsdatum

04-1992

Peer-reviewed

Ja

ÖFOS 2012

106001 Allgemeine Biologie

Schlagwörter

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/membrane-potential-modulates-release-of-tumor-necrosis-factor-in-lipopolysaccharidestimulated-mouse-macrophages(20dd3b9b-b196-4b7c-8652-642ea5169376).html