title: Acute regulation of activin A and its binding protein, follistatin, in serum and tissues following lipopolysaccharide treatment of adult male mice.
abstract: Activin A, a member of the transforming growth factor-β family, increases in the circulation within 1 h after administration of bacterial LPS. To clarify the origins of this rapid increase, the distribution of activin A and its binding protein, follistatin, and their production following LPS treatment, were assessed in adult male mice. In untreated mice, activin A was detectable in all 23 tissues examined, with highest mRNA expression (as measured by quantitative RT-PCR) was found in the liver, and the largest concentration of activin A protein (by ELISA) was found in the bone marrow. Likewise, follistatin mRNA and protein were present in all tissues, with highest expression in the vas deferens. Activin A and follistatin mRNA did not increase significantly in any tissue within the first hour after LPS, but activin A protein decreased by 35% in the bone marrow and increased 5-fold in the lung. No significant changes were observed in any other tissue. Activin A reached a peak in the circulation 1 h following LPS, and then declined. Cycloheximide, an inhibitor of protein translation, reduced this increase of activin A by more than 50%. Actinomycin D, an inhibitor of mRNA transcription, had no effect. Circulating follistatin did not increase until 4 h after LPS and was not affected by either inhibitor. These data indicate that the rapid increase in circulating activin A during LPS-induced inflammation is regulated at the posttranscriptional level, apparently from newly translated and stored protein, and implicate bone marrow-derived cells, and, in particular, neutrophils, as a significant source of this preformed activin A.
authors.affiliation: Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia. hui.wu@monash.edu
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Wendy R
authors.initials: WR
authors.lastname: Winnall
authors.forename: David J
authors.initials: DJ
authors.lastname: Phillips
authors.forename: Mark P
authors.initials: MP
authors.lastname: Hedger
mesh_terms: D028341:Activins / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D003609:Dactinomycin / Q000494:pharmacology; D038681:Follistatin / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D008070:Lipopolysaccharides / Q000633:toxicity*; D008297:Male; D051379:Mice; D021122:Protein Subunits; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D038681:Follistatin; D008070:Lipopolysaccharides; D021122:Protein Subunits; D012333:RNA, Messenger; C422405:activin A; D028341:Activins; D003609:Dactinomycin