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Published on: April 9, 2013
A simple method for measuring the F-actin content of human polymorphonuclear leukocytes in whole blood
1Institute of Pathophysiology, Karl-Franzens University, Graz, Heinrichstr. 31, A-8010 Graz, Austria. Egger@leukotec.com
Abstract:
We have developed an improved method for measuring the filamentous (F) actin content of human blood polymorphonuclear leukocytes (PMNs). The essential feature of the method is the immediate fixation of the F-actin cytoskeleton. Fresh whole blood (100 microliters) is shock-cooled by the addition of 1.0 ml of a mixture of 18.75% glycerol and 5% formaldehyde in phosphate buffer pre-cooled to -8 degrees C and subsequently fixed at 4 degrees C for 15 min. After lysis in distilled water and removal of the red blood cells by centrifugation, the F-actin cytoskeleton of the PMNs is stained with fluorescein isothiocyanate (FITC)-phalloidin and quantified by means of flow cytometry. In healthy test subjects, PMN stimulation by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP) for 20 s resulted in a significantly increased F-actin assembly, while in patients with multiple organ failure, two subpopulations arose: one with greater F-actin content and a second with lower F-actin content in comparison with the unstimulated blood sample. This simple and fast method may be a useful tool in basic and clinical research.
Insights
This study presents a new, rapid method to measure filamentous actin in human polymorphonuclear leukocytes (PMNs). The technique aids in distinguishing F-actin assembly differences in healthy individuals versus those with multiple organ failure.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Filamentous (F) actin dynamics are crucial for polymorphonuclear leukocyte (PMN) function.
- Accurate measurement of F-actin content is essential for understanding cellular responses.
- Existing methods may lack the speed or sensitivity required for rapid cellular analysis.
Purpose of the Study:
- To develop and validate an improved, rapid method for quantifying F-actin content in human PMNs.
- To assess F-actin assembly in response to stimulation in healthy subjects.
- To investigate F-actin content variations in patients with multiple organ failure.
Main Methods:
- Immediate fixation of F-actin cytoskeleton using a shock-cooling technique with glycerol and formaldehyde.
- Isolation and staining of PMNs with fluorescein isothiocyanate (FITC)-phalloidin.
- Quantification of F-actin using flow cytometry.
Main Results:
- The novel method allows for rapid F-actin measurement.
- PMN stimulation with formyl-methionyl-leucyl-phenylalanine (FMLP) significantly increased F-actin assembly in healthy individuals.
- Patients with multiple organ failure exhibited two distinct PMN subpopulations with differing F-actin content compared to unstimulated samples.
Conclusions:
- This simple and fast method provides a reliable way to measure F-actin content in human PMNs.
- The technique can differentiate F-actin assembly patterns in health and disease states.
- This method holds potential utility in both basic and clinical research settings.
