The Biphasic Effect of Lipopolysaccharide on Membrane Potential

Lipopolysaccharide (LPS) from certain strains of Gram-negative bacteria can induce a rapid (<1 s) hyperpolarization of membrane potential, followed by a gradual depolarization exceeding the initial resting membrane potential. Through overexpression of a <i>Drosophila</i> ORK1 two-pore...

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Main Authors: Maria E. Hadjisavva, Robin L. Cooper
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Membranes
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Online Access:https://www.mdpi.com/2077-0375/15/3/74
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author Maria E. Hadjisavva
Robin L. Cooper
author_facet Maria E. Hadjisavva
Robin L. Cooper
author_sort Maria E. Hadjisavva
collection DOAJ
description Lipopolysaccharide (LPS) from certain strains of Gram-negative bacteria can induce a rapid (<1 s) hyperpolarization of membrane potential, followed by a gradual depolarization exceeding the initial resting membrane potential. Through overexpression of a <i>Drosophila</i> ORK1 two-pore-domain K<sup>+</sup> channel (K2P) in larval muscles and altering the external concentrations of K<sup>+</sup> and Na<sup>+</sup> ions, it is clear that the hyperpolarization is due to activating K2P channels and the depolarization is due to promoting an inward Na<sup>+</sup> leak. When the external Na<sup>+</sup> concentration is negligible, the LPS-delayed depolarization is dampened. The hyperpolarization induced by LPS can exceed −100 mV when external K<sup>+</sup> and Na<sup>+</sup> concentrations are lowered. These results indicate direct action by LPS on ion channels independently of immune responses. Such direct actions may need to be considered when developing clinical treatments for certain forms of bacterial septicemia.
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spelling doaj-art-e495f283daee4370b1073384b7a702c22025-08-20T01:48:41ZengMDPI AGMembranes2077-03752025-03-011537410.3390/membranes15030074The Biphasic Effect of Lipopolysaccharide on Membrane PotentialMaria E. Hadjisavva0Robin L. Cooper1Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USADepartment of Biology, University of Kentucky, Lexington, KY 40506-0225, USALipopolysaccharide (LPS) from certain strains of Gram-negative bacteria can induce a rapid (<1 s) hyperpolarization of membrane potential, followed by a gradual depolarization exceeding the initial resting membrane potential. Through overexpression of a <i>Drosophila</i> ORK1 two-pore-domain K<sup>+</sup> channel (K2P) in larval muscles and altering the external concentrations of K<sup>+</sup> and Na<sup>+</sup> ions, it is clear that the hyperpolarization is due to activating K2P channels and the depolarization is due to promoting an inward Na<sup>+</sup> leak. When the external Na<sup>+</sup> concentration is negligible, the LPS-delayed depolarization is dampened. The hyperpolarization induced by LPS can exceed −100 mV when external K<sup>+</sup> and Na<sup>+</sup> concentrations are lowered. These results indicate direct action by LPS on ion channels independently of immune responses. Such direct actions may need to be considered when developing clinical treatments for certain forms of bacterial septicemia.https://www.mdpi.com/2077-0375/15/3/74bacteriaendotoxinK2Plipopolysaccharidemembrane potentialNALCN
spellingShingle Maria E. Hadjisavva
Robin L. Cooper
The Biphasic Effect of Lipopolysaccharide on Membrane Potential
Membranes
bacteria
endotoxin
K2P
lipopolysaccharide
membrane potential
NALCN
title The Biphasic Effect of Lipopolysaccharide on Membrane Potential
title_full The Biphasic Effect of Lipopolysaccharide on Membrane Potential
title_fullStr The Biphasic Effect of Lipopolysaccharide on Membrane Potential
title_full_unstemmed The Biphasic Effect of Lipopolysaccharide on Membrane Potential
title_short The Biphasic Effect of Lipopolysaccharide on Membrane Potential
title_sort biphasic effect of lipopolysaccharide on membrane potential
topic bacteria
endotoxin
K2P
lipopolysaccharide
membrane potential
NALCN
url https://www.mdpi.com/2077-0375/15/3/74
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