title: Surfactant protein A modulates the lipopolysaccharide-induced inflammatory response related to preterm birth.
abstract: Surfactant protein A (SP-A) functions in homeostasis of lung surfactant and in innate immunity. SP-A is secreted by the fetal lung into amniotic fluid. Additionally it has been detected in gestational tissues. We propose that SP-A influences intrauterine inflammation that is commonly associated with preterm birth, the main underlying cause of neonatal mortality and morbidity. We used our previously established mouse model of LPS-induced preterm birth of live-born pups to investigate the role of SP-A in preterm birth. Mice overexpressing rat SP-A (rSP-A) under the control of human SP-C promoter were used. Cytokine concentrations in maternal and fetal serum and in amniotic fluid and mRNA levels of several inflammatory mediators in lungs and in intrauterine tissues were quantified using Cytometric Bead Array and RNase Protection Assay, respectively. Higher levels of SP-A mRNA were observed in fetal lungs and intrauterine tissues of rSP-A mice compared with wild-type. Using Western blot we detected excess of SP-A protein in fetal lung and in amniotic fluid of rSP-A animals. Despite some differences in the basal levels of TNF-α and IL-10 between rSP-A and wild-type animals, there were no differences in the duration of pregnancy. However, the levels of TNF-α, IL-10 and some other inflammatory mediators in intrauterine tissues and in amniotic fluid differed significantly between the mouse lines after maternal LPS given at 17dpc. We conclude that SP-A modulates the levels of intrauterine inflammatory mediators involved in preterm birth and may contribute to inflammatory processes related to spontaneous preterm labor.
authors.affiliation: Institute of Clinical Medicine, Department of Pediatrics, Biocenter Oulu, FI-90014 University of Oulu, Finland. annamari.salminen@oulu.fi
authors.forename: Annamari
authors.initials: A
authors.lastname: Salminen
authors.forename: Reetta
authors.initials: R
authors.lastname: Vuolteenaho
authors.forename: Reija
authors.initials: R
authors.lastname: Paananen
authors.forename: Marja
authors.initials: M
authors.lastname: Ojaniemi
authors.forename: Mikko
authors.initials: M
authors.lastname: Hallman
mesh_terms: D000818:Animals; D005260:Female; D005434:Flow Cytometry; D007249:Inflammation / Q000503:physiopathology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D047928:Premature Birth; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D037662:Pulmonary Surfactant-Associated Protein A; D012333:RNA, Messenger; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4