title: Identification of grass carp IL-10 receptor subunits: functional evidence for IL-10 signaling in teleost immunity.
abstract: Although the functions of teleost IL-10 have been preliminarily determined, functional evidence for its receptor signaling is lacking. Particularly, the identity of fish IL-10 receptor 2 (IL-10R2) is ambiguous. Cytokine receptor family member b4 (CRFB4) and CRFB5 are likely the ortholog of mammalian IL-10R2. In this study, grass carp CRFB4 (gcCRFB4) and gcCRFB5 cDNAs were isolated and characterized. The relatively high expression levels of grass carp IL10 receptor 1 (gcIL-10R1), gcCRFB4 and gcCRFB5 in immune tissues and cells implied their importance in fish immunity. Accordingly, gcIL-10R1, gcCRFB4 and gcCRFB5 were overexpressed in a grass carp kidney cell line to identify the IL-10 receptor subunits upon grass carp IL-10 (gcIL-10) treatment. Results showed that gcIL-10R1 was essential for gcIL-10 stimulation on STAT3 activation and grass carp suppressor of cytokine signaling 3 (gcSOCS3) promoter activity, and also indicated that gcCRFB4 but not gcCRFB5 might be the ortholog of mammalian IL-10R2. Furthermore, mutation of a putative STAT3-binding element in gcSOCS3 promoter attenuated the stimulation of gcIL-10 on gcSOCS3 promoter activity, indicating that gcIL-10 may modulate gcSOCS3 transcription at least partly via STAT3 activation. This notion was further supported by our observation that gcIL-10 was able to induce STAT3 phosphorylation and STAT3 inhibitor could abolish the upregulation of gcSOCS3 mRNA expression by gcIL-10 in grass carp head kidney leukocytes. Taken together, this study for the first time functionally characterized the teleost IL-10 receptor subunits and clarified the conservation of fish IL-10 signaling during evolution, thus laying the ground for further understanding the critical immune events led by IL-10 in teleost.
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Wei
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China.
authors.forename: Xinyan
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China.
authors.forename: Anying
authors.initials: A
authors.lastname: Zhang
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China.
authors.forename: Linyong
authors.initials: L
authors.lastname: Du
authors.affiliation: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China. Electronic address: zhouhongzh@uestc.edu.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002347:Carps / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D029941:Fish Proteins / Q000276:immunology* / Q000378:metabolism; D060226:Head Kidney / Q000276:immunology; D016753:Interleukin-10 / Q000378:metabolism*; D053710:Interleukin-10 Receptor beta Subunit / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D053701:Receptors, Interleukin-10 / Q000276:immunology* / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D029941:Fish Proteins; D053710:Interleukin-10 Receptor beta Subunit; D053701:Receptors, Interleukin-10; D050796:STAT3 Transcription Factor; D016753:Interleukin-10
keywords: Functional identification; IL-10 regulation; IL-10 signaling; IL10 receptors; Teleost