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Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia
R Fiorini1, G P Littarru, G V Coppa
1Department of Biochemistry, University of Ancona, Ancona, Italy.
Insights
Polymorphonuclear leucocytes (PMN) from children with primary ciliary dyskinesia (PCD) exhibit increased plasma membrane polarity. This alteration in PMN membrane properties may explain their abnormal movement and could stem from cytoskeletal defects.
Area of Science:
- Cell Biology
- Immunology
- Genetics
Background:
- Primary ciliary dyskinesia (PCD) is a genetic disorder affecting ciliary function.
- Polymorphonuclear leucocytes (PMN) in PCD patients display abnormal motility.
- PMN locomotion is regulated by plasma membrane biochemical events.
Purpose of the Study:
- To investigate the plasma membrane polarity of PMN in children with PCD.
- To explore the relationship between PMN membrane polarity and PCD.
Main Methods:
- Utilized the fluorescent probe Laurdan to measure PMN membrane polarity in 11 children with PCD and healthy controls.
- Assessed the impact of colchicine, a microtubule-disrupting agent, on PMN membrane polarity.
Main Results:
- PMN from PCD patients showed a significant red shift in Laurdan spectra, indicating increased membrane polarity compared to controls.
- Colchicine treatment induced a similar spectral shift in PMN, suggesting a link between microtubule function and membrane polarity.
Conclusions:
- PMN in children with PCD possess elevated plasma membrane polarity.
- This increased polarity may underlie the observed defects in PMN locomotory activity.
- Cytoskeletal abnormalities are a potential cause of these membrane alterations in PCD.
Background:
Polymorphonuclear leucocytes (PMN) from subjects with primary ciliary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN from children with PCD.
Design:
Membrane polarity was studied in 11 children with PCD and in healthy controls by measuring the steady-state fluorescence excitation and emission spectra of 2-dimethylamino[6-lauroyl]naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surroundings. Laurdan shows a marked steady-state emission red shift in polar solvents, with respect to nonpolar solvents. Moreover, the effect of the microtubule disassembling agent colchicine on PMN membrane polarity was evaluated.
Result:
Our results show a red shift of the fluorescence excitation and emission spectra of Laurdan in PMN from the PCD group with respect to the control group. These data indicate an increase in membrane polarity of PMN from the PCD group. Treatment of PMN with colchicine induced a red shift in the Laurdan excitation and emission spectra with the same trend observed in PMN from the PCD group.
Conclusion:
PMN from children with PCD are characterized by an increased plasma membrane polarity. These changes could be the basis of the modifications in the locomotory activities of PMN. The observed alterations may be attributed to abnormalities in the cytoskeleton.