title: Expression analysis of nine Toll-like receptors in yellow catfish (Pelteobagrus fulvidraco) responding to Aeromonas hydrophila challenge.
abstract: Toll-like receptors (TLRs) are important components of pattern recognition receptors (PRRs), which play significant roles in innate immunity to defense against pathogen invasion. Many TLRs have been found in teleosts, but there are no reports about cloning and expression of TLR genes in yellow catfish (Pelteobagrus fulvidraco). In this study, we analyzed the sequence characters and the relative mRNA expression levels of nine TLRs (TLR1, TLR2, TLR3, TLR4-1, TLR5, TLR7, TLR8-2, TLR9 and TLR22) in different tissues of yellow catfish. The results showed that all nine TLR genes are highly expressed in head kidney, trunk kidney, spleen and liver, all of which are related to host immunity. Subsequently we used Aeromonas hydrophila as a stimulating agent to detect the expression profiles of these nine TLRs in the liver, spleen, trunk kidney and head kidney of yellow catfish at different time points after injection with killed Aeromonas hydrophila. All nine TLRs responded to A. hydrophila challenge with tissue-specific patterns in different immune tissues. The kinetics of up- or down-regulation of these nine TLRs exhibited a similar trend, rising to an elevated level at first and then falling to the basal level, but the peak value differed at different time points in different tissues. The expression levels of the TLR3, TLR4-1, TLR9 and TLR22 genes were significantly up-regulated after bacterial challenge in the liver, spleen, head kidney and trunk kidney. The relatively high expression of TLR genes in the immune tissues in response to the A. hydrophila challenge indicated that TLRs may play important roles in the innate immune response against gram-negative bacteria in yellow catfish.
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China.
authors.forename: Xiao-Ting
authors.initials: XT
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China.
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Zhang
authors.affiliation: Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China; Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Ze-Chao
authors.initials: ZC
authors.lastname: Shi
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China.
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China.
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China. Electronic address: kjwei@mail.hzau.edu.cn.
authors.forename: Kai-Jian
authors.initials: KJ
authors.lastname: Wei
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Wuhan 430070, China. Electronic address: wei-ji@mail.hzau.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000818:Animals; D002397:Catfishes; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D007113:Immunity, Innate; D010802:Phylogeny; D000072417:Protein Domains; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000662:veterinary; D051193:Toll-Like Receptors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D051193:Toll-Like Receptors
keywords: Aeromonas hydrophila; Gene expression; Innate immunity; Intraperitoneal injection; Toll-like receptors; Yellow catfish