title: Pineal arylalkylamine N-acetyltransferase (Aanat) gene expression as a target of inflammatory mediators in the chicken.
abstract: Previously, we demonstrated that experimental peritonitis in chickens was attenuated by treatment with exogenous melatonin, while the developing inflammation decreased pineal AANAT activity. This suggested the existence of a bidirectional relationship between the activated immune system and pineal gland function. The aim of the present study was to identify the step(s) in the chicken pineal melatonin biosynthetic pathway that are affected by inflammation. Peritonitis was evoked by i.p. injection of thioglycollate solution, either 2h after the start, or 2h before the end of the light period, and the animals were sacrificed 4h later. The effect of inflammation on the expression of genes encoding enzymes participating in melatonin biosynthesis in the pineal gland, i.e. tryptophan hydroxylase 1 (Tph1), dopa decarboxylase (Ddc), arylalkylamine N-acetyltransferase (Aanat) and acetylserotonin O-methyltransferase (Asmt), was evaluated by qPCR. The pineal and serum melatonin concentration as well as the content of its precursors in the pineal gland were measured, along with the activity of the relevant biosynthetic enzymes. Developing peritonitis caused an increase in the pineal levels of the Tph1 mRNA during the night and the Asmt mRNA during the day, while nocturnal Aanat transcription was reduced. Both the pineal and serum melatonin level and the pineal content of N-acetylserotonin (NAS) were decreased during the night in birds with peritonitis. The amount and activity of pineal AANAT were significantly reduced, while the activity of HIOMT was increased under these experimental conditions. These results indicate that the observed decrease in MEL biosynthesis in chickens with developing inflammation is a result of transcriptional downregulation of the Aanat gene, followed by reduced synthesis and activity of the encoded enzyme.
authors.affiliation: Department of Animal Physiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland. apiesiewicz@biol.uw.edu.pl
authors.forename: Aneta
authors.initials: A
authors.lastname: Piesiewicz
authors.forename: Urszula
authors.initials: U
authors.lastname: Kedzierska
authors.forename: Iwona
authors.initials: I
authors.lastname: Adamska
authors.forename: Michal
authors.initials: M
authors.lastname: Usarek
authors.forename: Michal
authors.initials: M
authors.lastname: Zeman
authors.forename: Krystyna
authors.initials: K
authors.lastname: Skwarlo-Sonta
authors.forename: Pawel Marek
authors.initials: PM
authors.lastname: Majewski
mesh_terms: D000121:Acetylserotonin O-Methyltransferase / Q000096:biosynthesis; D000818:Animals; D047068:Arylalkylamine N-Acetyltransferase / Q000096:biosynthesis* / Q000235:genetics; D002645:Chickens / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology; D004296:Dopa Decarboxylase / Q000096:biosynthesis; D015536:Down-Regulation; D018836:Inflammation Mediators / Q000502:physiology*; D008297:Male; D008550:Melatonin / Q000096:biosynthesis*; D010538:Peritonitis / Q000139:chemically induced / Q000503:physiopathology*; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology*; D012333:RNA, Messenger / Q000378:metabolism; D012701:Serotonin / Q000031:analogs & derivatives / Q000378:metabolism; D013864:Thioglycolates; D014365:Tryptophan Hydroxylase / Q000096:biosynthesis
chemical_list: D018836:Inflammation Mediators; D012333:RNA, Messenger; D013864:Thioglycolates; D012701:Serotonin; D014365:Tryptophan Hydroxylase; D000121:Acetylserotonin O-Methyltransferase; D047068:Arylalkylamine N-Acetyltransferase; D004296:Dopa Decarboxylase; D008550:Melatonin; C006389:N-acetylserotonin