title: The inhibitory role of γ-aminobutyric acid (GABA) on immunomodulation of Pacific oyster Crassostrea gigas.
abstract: γ-aminobutyric acid (GABA) is an inhibitory neurotransmitter to suppress the immune-mediated pro-inflammatory reactions, and it has been used in the treatment of many inflammation-related diseases in vertebrates, while its immunomodulatory role in invertebrates has never been reported. In the present study, GABA was found to exist in the hemolymph of Pacific oyster Crassostrea gigas, and its concentration decreased slightly from 8.00 ± 0.37 μmol L(-1) at normal condition to 7.73 ± 0.15 μmol L(-1) at 6 h after LPS stimulation, and then increased to 9.34 ± 0.15 μmol L(-1), 8.86 ± 0.68 μmol L(-1) at 12 h and 48 h, respectively. After LPS stimulation, the mRNA expressions of pro-inflammatory cytokines (CgIL-17 and CgTNF) and immune effectors (CgSOD and CgBPI), and the protein expression of NOS increased significantly, and these increased trends were remarkably inhibited by GABA stimulation. At the same time, the phagocytosis rate and apoptosis rate of immunocytes also increased obviously after LPS stimulation, whereas the increase was repressed with the addition of GABA. The results collectively demonstrated that GABA was an indispensable inhibitory agent for both humoral and cellular immune response, which mainly functioned at the late phase of immune response to avoid the excess immune reactions and maintain the immune homeostasis.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Meijia
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Limei
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China. Electronic address: wanglingling@ms.qdio.ac.cn.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Weilin
authors.initials: W
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lusheng
authors.initials: L
authors.lastname: Xin
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhaoqun
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D018682:GABA Agents / Q000494:pharmacology; D056747:Immunomodulation / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D018682:GABA Agents; D008070:Lipopolysaccharides; D005680:gamma-Aminobutyric Acid
keywords: Crassostrea gigas; Immune response; Immunomodulation; Inhibitory neurotransmitter; γ-aminobutyric acid