PMID- 2294151 OWN - NLM STAT- MEDLINE DCOM- 19900201 LR - 20190516 IS - 0741-5400 (Print) IS - 0741-5400 (Linking) VI - 47 IP - 1 DP - 1990 Jan TI - Lipopolysaccharide modulates chemotactic peptide-induced actin polymerization in neutrophils. PG - 13-24 AB - To study the effect of endotoxin (LPS) on the basal and chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (fMLP)-induced alterations in neutrophil cytoskeleton, we purified (greater than 98%) LPS-free neutrophils (LPS- less than 10 pg/ml LPS), compared their cytoskeletal organization to that of circulating neutrophils, and examined the effect of LPS exposure on the basal and fMLP-induced change in the cytoskeleton as reflected by F-actin content and distribution. Shape, F-actin content and distribution were monitored by FACS analysis and fluorescence microscopy of NBDphallicidin-stained cells. The F-actin content of basal and fMLP-activated, purified LPS- cells is similar to that of circulating neutrophils (defined as cells drawn in LPS- buffers at 37 degrees C and analyzed after less than 10 seconds of ex vivo manipulation). LPS- cells are round with a diffuse F-actin distribution. Exposure of LPS- cells to LPS causes cell polarization and F-actin redistribution without net gain in F-actin content. Peptide activation of the LPS- cell causes actin polymerization, which is preceded by a brief lag time. Exposure of LPS- cells to LPS (LPS+) enhances fMLP-induced actin polymerization by: 1) increasing the maximal extent of polymerization; 2) shortening the lag time preceding polymerization and increasing the rate of polymerization; and 3) lowering fMLP dose required for half maximal F-actin response. The enhancement depends on LPS dose, duration of exposure, and temperature. To examine the mechanism whereby LPS enhances fMLP-induced actin polymerization, we determined the predominant end for filament growth in LPS- and LPS+ cells, the number of actin nuclei generated in LPS- and LPS+ by fMLP activation, and the number and affinity of fMLP receptors on LPS- and LPS+ cells by 3[H]fMLP binding. Actin polymerization in both LPS- and LPS+ occurs predominantly by monomer addition to the barbed ends of nuclei, and the number of actin nuclei in basal and fMLP-activated LPS- and LPS+ cells is similar. LPS+ cells express three times more fMLP receptors than LPS- cells. The results show that LPS- cells are similar in cytoskeletal organization to circulating neutrophils, LPS causes shape change without change in F-actin content, and LPS enhances fMLP-induced actin polymerization response in neutrophils. The results suggest that LPS enhancement of actin polymerization response is associated with an increase in the number of fMLP receptors expressed on the cell surface. FAU - Howard, T H AU - Howard TH AD - Department of Pediatrics, School of Medicine, University of Alabama, Birmingham. FAU - Wang, D AU - Wang D FAU - Berkow, R L AU - Berkow RL LA - eng GR - R01 AI25214/AI/NIAID NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - England TA - J Leukoc Biol JT - Journal of leukocyte biology JID - 8405628 RN - 0 (Actins) RN - 0 (Lipopolysaccharides) RN - 0 (Polymers) RN - 0 (Receptors, Formyl Peptide) RN - 0 (Receptors, Immunologic) RN - 59880-97-6 (N-Formylmethionine Leucyl-Phenylalanine) SB - IM MH - Actins/analysis/*metabolism MH - Humans MH - In Vitro Techniques MH - Lipopolysaccharides/*pharmacology MH - N-Formylmethionine Leucyl-Phenylalanine/*pharmacology MH - Neutrophils/*drug effects/metabolism MH - Polymers/metabolism MH - Receptors, Formyl Peptide MH - Receptors, Immunologic/analysis/drug effects EDAT- 1990/01/01 00:00 MHDA- 1990/01/01 00:01 CRDT- 1990/01/01 00:00 PHST- 1990/01/01 00:00 [pubmed] PHST- 1990/01/01 00:01 [medline] PHST- 1990/01/01 00:00 [entrez] AID - 10.1002/jlb.47.1.13 [doi] PST - ppublish SO - J Leukoc Biol. 1990 Jan;47(1):13-24. doi: 10.1002/jlb.47.1.13.