Involvement of H-Ras in the adaptive immunity of Nile tilapia by regulating lymphocyte activation

• Published in: Fish & shellfish immunology 2019-06, Vol.89, p.281-289
• Main Authors: Wei, Xiumei, Zhao, Tianyu, Zhang, Yu, Ai, Kete, Li, Huiying, Yang, Jialong
• Format: Article
• Language: English
• Subjects: Adaptive immunity; Evolution; H-Ras; Lymphocyte activation; Oreochromis niloticus
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2019.04.003

H-Ras is a guanosine triphosphatase (GTPase), which acts as a molecular switch and controls multiple important cellular processes including lymphocyte activation and function. However, regulatory mechanism of adaptive immune response by H-Ras remains unclear in non-mammalian animals. In the present study, we investigated the involvement of H-Ras in lymphocyte activation with a teleost model Oreochromis niloticus. H-Ras from O. niloticus (On-H-Ras) is highly conserved with those from other vertebrates. The mRNA of On-H-Ras showed a wide expression pattern in the lymphoid-tissues and with the highest level in liver. After Aeromonas hydrophila infection, transcription of On-H-Ras was significantly induced on day 8 but came back to basal level on day 16, suggesting that On-H-Ras potentially participated in primary response during the adaptive immunity. Furthermore, On-H-Ras mRNA was obviously up-regulated when leukocytes were activated by T lymphocyte mitogen PHA in vitro. Meanwhile, protein level of H-Ras was also augmented once leukocytes were stimulated with lymphocyte receptor signaling agonist PMA and ionomycin. More importantly, once Ras activity was inhibited by specific inhibitor, the up-regulation of lymphocyte activation marker CD122 was obviously impaired during lymphocyte activation process. Therefore, On-H-Ras regulated lymphocyte activation through both mRNA and protein level. Altogether, our results illustrated the involvement of H-Ras in teleost adaptive immunity via controlling lymphocyte activation, and thus provided a novel perspective to understand evolution of the lymphocyte-mediated adaptive immunity. •h-Ras from Nile Tilapia O. niloticus is an evolutionary conserved GTPase.•On-h-Ras expresses widely in lymphoid-related tissues.•On-h-Ras involves in primary response of the adaptive immunity.•h-Ras regulates lymphocytes activation of Nile tilapia on mRNA and protein level.