title: Evidence for pituitary adenylate cyclase-activating peptide as a direct immunoregulator in teleost head kidney.
abstract: In mammals, pituitary adenylate cyclase activating polypeptide (PACAP) is a potent anti-inflammatory factor, showing that it inhibits the expression and release of proinflammatory cytokines and enhances the production of anti-inflammatory factors. However, whether fish PACAP plays similar regulatory roles as seen in mammals remains unclear. In the present study, expression of PACAP-specific receptor PAC1-R was shown in grass carp head kidney and spleen, supporting that PACAP may have a direct effect on fish immune cells. To test this hypothesis, the immunoregulatory role of grass carp PACAP (gcPACAP) was examined in head kidney leucocytes (HKLs). Results showed that gcPACAP inhibited basal and further attenuated lipopolysaccharide (LPS)-stimulated cell viability of HKLs, indicating that gcPACAP may possess similar inhibitory property at cellular level as seen in mammals. Curiously, in vitro and in vivo studies revealed that gcPACAP stimulated proinflammatory factors (IL-1β and TNF-α) but not IL-10 mRNA expression in HKLs and head kidney. Moreover, bacterial infection and LPS enhanced IL-1β, TNF-α and IL-10 mRNA expression in grass carp head kidney and HKLs, respectively, and these stimulatory effects were not influenced by gcPACAP. These findings suggest that PACAP plays distinct roles, at least does not function as an anti-inflammatory factor, in fish compared with that in mammals.
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China.
authors.forename: Xinyan
authors.initials: X
authors.lastname: Wang
authors.forename: He
authors.initials: H
authors.lastname: Wei
authors.forename: Taiqiang
authors.initials: T
authors.lastname: Zhao
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Zhu
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Danyan
authors.initials: D
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
mesh_terms: D016980:Aeromonas hydrophila / Q000276:immunology / Q000502:physiology; D000818:Animals; D002347:Carps; D005393:Fish Diseases / Q000276:immunology; D029941:Fish Proteins / Q000378:metabolism*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000662:veterinary*; D060226:Head Kidney / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D009928:Organ Specificity; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10