Surfactant protein A differentially regulates peripheral and inflammatory neutrophil chemotaxis.
Surfactant protein A (SP-A), a pulmonary lectin, plays an important role in regulating innate immune cell function. Besides accelerating pathogen clearance by pulmonary phagocytes, SP-A also stimulates alveolar macrophage chemotaxis and directed actin polymerization. We hypothesized that SP-A would also stimulate neutrophil chemotaxis. With the use of a Boyden chamber assay, we found that SP-A (0.5-25 microg/ml) did not stimulate chemotaxis of rat peripheral neutrophils or inflammatory bronchoalveolar lavage (BAL) neutrophils isolated from LPS-treated lungs. However, SP-A affected neutrophil chemotaxis toward the bacterial peptide formyl-met-leu-phe (fMLP). Surprisingly, the effect was different for the two neutrophil populations: SP-A reduced peripheral neutrophil chemotaxis toward fMLP (49 +/- 5% fMLP alone) and enhanced inflammatory BAL neutrophil chemotaxis (277 +/- 48% fMLP alone). This differential effect was not seen for the homologous proteins mannose binding lectin and complement protein 1q but was recapitulated by type IV collagen. SP-A bound both neutrophil populations comparably and did not alter formyl peptide binding. These data support a role for SP-A in regulating neutrophil migration in pulmonary tissue.
Schagat
Trista L
TL
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
Wofford
Jessica A
JA
Greene
Kelly E
KE
Wright
Jo Rae
JR
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D039481:CD11b Antigen / Q000378:metabolism; D002630:Chemotactic Factors / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology; D011014:Pneumonia / Q000503:physiopathology*; D037662:Pulmonary Surfactant-Associated Protein A / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism; D018000:Receptors, Peptide / Q000187:drug effects / Q000378:metabolism
D039481:CD11b Antigen; D002630:Chemotactic Factors; D037662:Pulmonary Surfactant-Associated Protein A; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D009240:N-Formylmethionine Leucyl-Phenylalanine