Nrf2 is involved in osmoregulation, antioxidation and immunopotentiation in Coilia nasus under salinity stress

Abstract

Coilia nasus is a rare anadromous fish species found in China’s Yangtze River and is a precious commercial commodity. The anti-stress mechanism of C. nasus has become the focus of research due to the animal’s strong stress responses. Salinity has been reported to weaken the C. nasus stress response. Nrf2 is an important anti-stress transcription factor that plays key regulatory roles in mediating salinity stress. In the present study, we cloned the full-length sequence of C. nasus Nrf2 for the first time and evaluated its differential expression in tissues. We also investigated the regulatory role of Nrf2 in osmoregulation, antioxidation and immunopotentiation in C. nasus under salinity stress. The results indicate that the C. nasus Nrf2 sequence is highly conserved. C. nasus Nrf2 is activated and plays a coordinated osmoregulatory role together with AQP1 under salinity stress and stimulates the activity of downstream antioxidant enzymes, including superoxide dismutase, glutathione peroxidase and so on. Nrf2 also triggers immunopotentiation via stimulation of lysozyme activity and an elevation of white blood cell counts. All of these C. nasus constructed adaptive Nrf2 regulatory networks act in response to salinity stress. This study lays a theoretical foundation for further research on the anti-stress mechanisms of C. nasus and will provide a reference for the further optimization of the C. nasus breeding mode.