Forschungsdatenbank PMU-SQQUID

PMU-Autor/inn/en

Abstract

BACKGROUND/AIMS
Phagocytosis depends on the formation of engulfment pseudopodia surrounding the target. We tested in microglia, monocyte-derived cells in the brain, whether a swelling-activated Cl(-)-current (I(Cl,swell)), required for global cell volume (CV) regulation, also contributes to local expansion and retraction of engulfment pseudopodia.
We used scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) to visualize and quantify the uptake of polystyrene microbeads (MBs) by microglial cells. Flow cytometry was used for cell volume measurments and I(Cl,swell) was measured by whole-cell patch clamp.
We found that exposure of microglial BV-2 cells to MBs in Cl(-)-free extracellular solution attenuated MB uptake and that the Cl(-)-channel blockers DIOA, flufenamic acid, NPPB and DCPIB suppressed the uptake of MBs in BV-2 cells and in primary microglial cells. Microglial cells exposed to MBs in the presence of Cl(-) channel blockers failed to extend engulfment pseudopodia. We observed that cells containing at least three MBs revealed an about twofold increase in current density of I(Cl, swell) compared to cells without MB. Osmotic challenges to stimulate global CV regulation before exposure to MBs modulated phagocytosis. Pre-conditioning of cells in hypo- or hypertonic medium for 12-16 hours caused a decrease in MB uptake.
These findings indicate that I(Cl,swell) contributes to formation of engulfment pseudopodia and participates in engulfment and particle uptake in microglial cells.

Useful keywords (using NLM MeSH Indexing)

Acetates/pharmacology

Animals

Calcium Channel Blockers/pharmacology*

Cell Size

Cells, Cultured

Chloride Channels/antagonists*

inhibitors*

Chloride Channels/metabolism

Cyclopentanes/pharmacology

Flow Cytometry

Flufenamic Acid/pharmacology

Indans/pharmacology

Indenes/pharmacology

Mice

Mice, Inbred C57BL

Microglia/cytology

Microglia/metabolism

Microscopy, Confocal

Microscopy, Electron, Scanning

Microspheres

Nitrobenzoates/pharmacology

Patch-Clamp Techniques

Phagocytosis/drug effects

Polystyrenes/chemistry

Pseudopodia/drug effects*

Pseudopodia/physiology

Find related publications in this database (Keywords)