title: Inhibition of miR-92d-3p enhances inflammation responses in genetically improved farmed tilapia (GIFT, Oreochromis niloticus) with Streptococcus iniae infection by modulating complement C3.
abstract: MicroRNAs (miRNAs) are small, non-coding RNAs that regulate target gene expression by binding to the 3'-untranslated regions (3'-UTRs) of their target mRNAs. The miR-92 family is an important miRNA family, which was discovered to be related to regulation of tumor proliferation, apoptosis, invasion, and metastasis. Inhibition of miR-92d-3p was found previously in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to Streptococcus iniae infection. In this study, we found that miR-92d-3p regulated complement C3 mRNA levels by binding to its 3'-UTR by 3'-UTR luciferase reporter assay, and reduced miR-92d-3p expression resulted in increased C3 mRNA levels. We detected a negative relationship between the expression levels of miR-92d-3p and C3 in GIFT injected with miRNA antagomir. We performed in vivo functional analysis by miR-92d-3p silencing. Inhibition of miR-92d-3p levels in GIFT head kidney caused a significant increase in C3 expression, which consequently increased the white blood cell counts and interleukin-1β, tumor necrosis factor-α, and interferon-γ mRNA levels, all of which may help to activate the inflammatory response in GIFT post-infection with S. iniae. Our findings indicate that miR-92d-3p regulated C3 levels by binding with the C3 mRNA 3'-UTR, and this interaction affected S. iniae infection induction and the immune response in GIFT. We concluded that miR-92d-3p plays an important role in modulating the inflammatory response in GIFT head kidney. Our findings may contribute to understanding the mechanisms of miRNA-mediated gene regulation in tilapia in response to S. iniae infection.
authors.affiliation: Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu, China. Electronic address: Qiangj@ffrc.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Qiang
authors.affiliation: Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China.
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Tao
authors.affiliation: Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu, China.
authors.forename: Jie
authors.initials: J
authors.lastname: He
authors.affiliation: Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Li
authors.affiliation: Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu, China. Electronic address: Xup@ffrc.cn.
authors.forename: Pao
authors.initials: P
authors.lastname: Xu
authors.affiliation: Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China.
authors.forename: Jin-Wen
authors.initials: JW
authors.lastname: Bao
authors.affiliation: Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu, China.
authors.forename: Yi-Lan
authors.initials: YL
authors.lastname: Sun
mesh_terms: D000818:Animals; D023681:Cichlids / Q000235:genetics; D003176:Complement C3 / Q000235:genetics* / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D007113:Immunity, Innate; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D013290:Streptococcal Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D000070058:Streptococcus iniae / Q000502:physiology
chemical_list: D003176:Complement C3; D029941:Fish Proteins; D035683:MicroRNAs
keywords: Complement C3; GIFT; Head kidney; Inflammatory response; miR-92d-3p