title: Induction of type I interferons in response to bacterial stimuli in large yellow croaker Larimichthys crocea.
abstract: In addition to the crucial roles in coordinating antiviral immune responses, type I interferons (IFNs) also play a role in the host immunity against bacterial pathogens. Our previous study identified two type I IFNs from large yellow croaker Larimichthys croaea(Lc), LcIFNd and LcIFNh, and showed their strong induction by poly(I:C) and antiviral activities. In the present study, both LcIFNd and LcIFNh were found to be rapidly induced in head kidney and spleen by mixed bacteria of Vibrio alginolyticus, Vibrio parahaemolyticus, and Aeromonas hydrophila. In the head kidney primary cells (HKCs), expression of these two LcIFN genes was increased by peptidoglycan (PGN) from Bacillus subtilis and lipopolysaccharide (LPS) from Escherichia coli. Consistently, Lc IFN-regulatory factor (LcIRF) 3 and LcIRF7, two key transcription factors of type I IFN expression, were also induced by these three bacteria, PGN, and LPS. These observations strongly suggested that large yellow croaker type I IFNs are involved in the immune response against bacterial infection. Luciferase assays showed that promoters of both LcIFNd and LcIFNh were activated by PGN, LPS, and genomic DNA of A. hydrophila, and A. hydrophila DNA was more potent than PGN and LPS in activating LcIFNd and LcIFNh promoters. Furthermore, the induction of LcIFNd promoter by these bacterial stimuli was further enhanced by the overexpression of LcIRF7 or LcIRF7 along with LcIRF3, while that of LcIFNh promoter was increased following the overexpression of LcIRF3 alone, suggesting that the induction of these two large yellow croaker IFNs by bacterial stimuli may be regulated via distinct manners. These results therefore revealed novel aspects of the functional regulation of teleost type I IFNs.
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China.
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China.
authors.forename: Jingqun
authors.initials: J
authors.lastname: Ao
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China. Electronic address: chenxinhua@tio.org.cn.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Chen
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000818:Animals; D004269:DNA, Bacterial / Q000494:pharmacology; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D060226:Head Kidney / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D007370:Interferon Type I / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D010457:Peptidoglycan / Q000494:pharmacology; D010473:Perciformes; D011401:Promoter Regions, Genetic; D013154:Spleen / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D014735:Vibrio Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D044149:Vibrio alginolyticus / Q000502:physiology; D014736:Vibrio parahaemolyticus / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D029941:Fish Proteins; D007370:Interferon Type I; D008070:Lipopolysaccharides; D010457:Peptidoglycan
keywords: Bacterial stimulation; Expression modulation; Large yellow croaker Larimichthys crocea; Promoter activation; Type I interferons