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A Fluorescence Fluctuation Spectroscopy Assay of Protein-Protein Interactions at Cell-Cell Contacts
Published on: December 1, 2018
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Filter-exchange spectroscopy is sensitive to gradual cell membrane degradation
Athanasia Kaika1, Geoffrey J Topping1, Luca Nagel1
1Department of Nuclear Medicine, TUM School of Medicine and Health, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany.
NMR in Biomedicine
|July 2, 2024
Summary
Filter-exchange spectroscopy (FEXSY) quantifies cell membrane permeability via apparent exchange rate (AXR). AXR changes detect early cell death, even before measurable changes in apparent diffusion coefficient (ADC).
Area of Science:
- Biophysics
- Cell Biology
- Magnetic Resonance Imaging
Background:
- Transmembrane water permeability alterations signify early necrotic cell death.
- Filter-exchange spectroscopy (FEXSY) quantifies water permeability using magnetic resonance.
- Apparent exchange rate (AXR) derived from FEXSY reflects water transport across cell membranes.
Purpose of the Study:
- To investigate changes in AXR during the progression of necrotic cell death.
- To evaluate the sensitivity of AXR to subtle membrane permeabilization.
- To explore the influence of T2 relaxation on AXR measurements in a two-compartment system.
Main Methods:
- FEXSY measurements were performed on yeast cells at various stages of necrosis.
- Results were compared with established fluorescence cell death markers and pulsed gradient spin echo (PGSE) measurements.
- Simulations were conducted to examine the effect of T2 relaxation and filter echo time (TEf) on AXR.
Main Results:
- AXR increased with increasing isopropanol concentration, indicating membrane permeabilization.
- Significant AXR changes were observed in vital yeast cells with compromised membranes, preceding significant ADC changes.
- Simulations showed that long TEf can lead to underestimation of AXR in multi-compartment systems.
Conclusions:
- AXR is a sensitive indicator of gradual cell membrane permeabilization in living cells.
- FEXSY can detect early-stage cell death through AXR changes, even at low isopropanol concentrations.
- AXR measurements offer a sensitive method for assessing cell membrane integrity without exogenous contrast agents.
