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Effect of PAF on human lymphocyte membranes: a fluorescence study
A Kantar1, P L Giorgi, R Fiorini
1Department of Pediatrics, University of Ancona, Italy.
Agents and Actions
|January 1, 1993
Summary
Platelet-activating factor (PAF) alters human lymphocyte membranes, increasing lipid order and reducing heterogeneity. These PAF-induced changes are reversible and mediated by PAF receptor interactions.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- Platelet-activating factor (PAF) is a potent lipid mediator involved in various physiological and pathological processes.
- Lymphocyte plasma membranes are crucial for immune cell function and communication.
- Understanding membrane dynamics is key to elucidating cellular responses to external stimuli.
Purpose of the Study:
- To investigate the impact of PAF on the biophysical properties of human lymphocyte plasma membranes.
- To determine if PAF affects membrane lipid order and heterogeneity.
- To explore the role of PAF-receptor interactions in these membrane alterations.
Main Methods:
- Utilized fluorescence spectroscopy techniques, specifically steady-state fluorescence anisotropy and fluorescence decay.
- Employed the fluorescent probe 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) to assess membrane properties.
- Investigated the effects of PAF and a PAF antagonist (L-659,989) on lymphocyte plasma membranes.
Main Results:
- PAF induced a significant, time-limited increase in lipid order in the outer region of lymphocyte plasma membranes.
- PAF was observed to decrease the heterogeneity of the lymphocyte plasma membranes.
- The observed membrane changes induced by PAF were effectively blocked by the PAF antagonist L-659,989.
Conclusions:
- PAF significantly modulates the physico-chemical organization of human lymphocyte plasma membranes.
- The observed alterations in membrane lipid order and heterogeneity are likely mediated by specific PAF-receptor interactions.
- These findings provide insights into the molecular mechanisms by which PAF influences lymphocyte function.