Molecular cloning and functional characterization of peptidoglycan recognition protein OmPGRP-L2 from the rainbow trout, Oncorhynchus mykiss

• Published in: Veterinary immunology and immunopathology Vol. 192; pp. 28 - 32
• Main Authors: Jang, Ju Hye, Kim, Hyun, Cho, Ju Hyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2017
• Subjects: Animals; Anti-inflammatory activity; Carrier Proteins - genetics; Carrier Proteins - metabolism; Carrier Proteins - physiology; Cloning, Molecular; Innate immunity; Interleukin-1beta - metabolism; Liver - metabolism; NF-kappa B - metabolism; Oncorhynchus mykiss - genetics; Oncorhynchus mykiss - immunology; Oncorhynchus mykiss - metabolism; Peptidoglycan recognition protein; Real-Time Polymerase Chain Reaction - veterinary; RTH-149; Sequence Analysis, DNA - veterinary; Teleost; Tumor Necrosis Factor-alpha - metabolism; Teleost; Innate immunity; Anti-inflammatory activity; Peptidoglycan recognition protein; RTH-149
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2017.09.004

•We identified a novel PGRP paralog, termed OmPGRP-L2 from Oncorhynchus mykiss.•OmPGRP-L2 is highly expressed in liver.•OmPGRP-L2 down-regulates IL-1β and TNF-α expression.•When overexpressed in RTH-149 cells, OmPGRP-L2 inhibits NF-κB activity.•OmPGRP-L2 might modulate the immune response to bacterial infection in rainbow trout. Peptidoglycan recognition proteins (PGRPs), a group of pattern recognition receptors (PRRs), are innate immune molecules that are structurally conserved through evolution in both invertebrate and vertebrate animals. In teleost fish, several PGRPs have been characterized recently. They have both amidase activity and bactericidal activity and are involved in indirectly killing bacteria and regulating multiple signaling pathways. However, the knowledge of functional similarity and divergence between PGRP paralogs for their role as an immune modulator in teleost fish is still limited. In this study, we identified a novel PGRP paralog, termed OmPGRP-L2 from the rainbow trout (Oncorhynchus mykiss). OmPGRP-L2 contains the conserved PGRP domain and the four Zn2+-binding amino acid residues required for amidase activity. Quantitative RT-PCR analysis indicated that OmPGRP-L2 is highly expressed in liver. Overexpression of OmPGRP-L2 in a rainbow trout hepatocyte cell line RTH-149 challenged with Edwardsiella tarda resulted in down-regulation of IL-1β and TNF-α expression. When overexpressed in RTH-149 cells, OmPGRP-L2 inhibited NF-κB activity with or without bacterial stimulation. Collectively, these findings suggest that OmPGRP-L2 has an immunomodulatory function, via NF-κB inhibition in liver.