Surfactant Releases Internal Calcium Stores in Neutrophils by G Protein-Mediated Pathway
Abstract
Pulmonary surfactant with surfactant-associated proteins (PS+SAP) decreases pulmonary inflammation by suppression of neutrophil activation, We have observed that PS+SAP inserts channels into artificial membranes, depolarizes neutrophils, decreases calcium influx following stimulation, and depresses neutrophil functions in vitro. We hypothesize that PS+SAP suppresses neutrophil activation by insertion of cation channels into plasma membrane, depolarization of neutrophils, and G protein-dependent release of Ca++ stores, and that gramicidin - a monovalent, cation channel protein - mimics these effects. Human neutrophils were monitored for Ca++ responses after exposure to gramicidin alone, gramicidin reconstituted with phospholipid (PLG), one of two different PS+SAP preparations, or a PSSAP preparation. !Ca+++1 responses were reexamined following preexposure to G protein or internal Ca++ release inhibitors. We observed that: 1)1% PS+SAP - but not PS-SAP - causes transient increases of neutrophil Ca++ within seconds of exposure; 2)1% PLG - but not gramicidin alone - closely mimics the effect of PS+SAP upon Ca++ response; 3) PS+SAP, gramicidin alone and PLG equally depolarizes neutrophils despite differences among neutrophil.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 07, 2002
- Accession Number
- ADA410729
Entities
People
- Mark E. Boston
Organizations
- Air Force Institute of Technology