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Phorbol myristate acetate induction of chemotactic migration of human polymorphonuclear neutrophils
W L Gabler1, W W Bullock, H R Creamer
1Department of Oral Molecular Biology, School of Dentistry, Oregon Health Sciences University, Portland 97201-3097.
Abstract:
The in vitro migration of human polymorphonuclear neutrophils (PMNs) was studied employing an enzymatic assay of cell migration with phorbol myristate acetate (PMA) as the test stimulant. Our data clearly show that PMA in concentrations between 1 and 100 ng/ml in the lower wells of blind-well chambers induced chemotactic migration. Chemokinesis (increased migration) was not induced when PMA was present in both the upper and lower chambers (i.e., in a nongradient mode). Clearly our data indicate that PMA is chemotactic for human PMNs and, coupled with published studies of the effect of PMA on PMNs, suggest activation of an intracellular gradient of membrane-associated protein kinase C as a possible new mechanism for the induction of oriented migration of PMNs. Such a mechanism may be generalized to include membrane-soluble materials (e.g., inflammatory mediators, microbial products), which establish internal gradients of activated PKC rather than via the "classic" agonist-surface receptor mechanism, providing an alternative pathway for the induction of leukocyte chemotaxis.
Insights
Phorbol myristate acetate (PMA) induces directed migration of human polymorphonuclear neutrophils (PMNs), indicating it is chemotactic. This suggests a novel mechanism involving intracellular protein kinase C gradients for leukocyte chemotaxis.
Area of Science:
- Immunology
- Cell Biology
Background:
- Leukocyte chemotaxis is crucial for immune responses.
- The mechanisms of directed cell migration are complex and involve various signaling pathways.
Purpose of the Study:
- To investigate the effect of phorbol myristate acetate (PMA) on human polymorphonuclear neutrophil (PMN) migration.
- To explore the potential role of intracellular protein kinase C (PKC) activation in PMN chemotaxis.
Main Methods:
- Utilized an enzymatic assay for in vitro cell migration.
- Employed blind-well chambers to assess PMN migration in response to PMA gradients.
- Tested PMA concentrations ranging from 1 to 100 ng/ml.
Main Results:
- PMA induced chemotactic migration of human PMNs in a concentration-dependent manner (1-100 ng/ml).
- PMA did not induce chemokinesis when present in both upper and lower chambers (non-gradient mode).
- Data indicate PMA is chemotactic for human PMNs.
Conclusions:
- PMA acts as a chemotactic agent for human PMNs.
- Suggests a novel mechanism for PMN chemotaxis involving intracellular gradients of activated PKC.
- This pathway may generalize to other membrane-soluble inflammatory mediators and microbial products.