Expression of phospholipase C β1 in olive flounder (Paralichthys olivaceus) following external stress stimulation

In this study, to clarify the function of PoPLC-β1, in response to stress challenge, we examined the PoPLC-β1 expression pattern in response to external stress (pathogen-associated molecular pathogen challenge and environmental challenge including temperature and salinity). PoPLC-β1 expression analysis of tissue from olive flounder showed that the messenger RNA (mRNA) was predominantly expressed in the brain, heart, eye, liver, spleen, and stomach. We also tested the mRNA expression of the PoPLC-β1 in the spleen and kidney of olive flounder by RT-PCR and real-time PCR following stimulation with lipopolysaccharide (LPS), concanavalin A (ConA), or polyinosinic:polycytidylic acid (PolyI:C) and compared with the inflammatory cytokines IL-1b and IL-6 in the stimulated flounder tissues. Each of the spleen and kidney and mRNA transcripts of PoPLC-β1 were increased 30and 10-fold than normal tissue at 1–6 h post injection (HPI) with PolyI:C when the expression of PoPLC-β1 transcript was similar to LPS and ConA. We also tested the expression of PoPLC-β1 in response to temperature and salinity stress. The expression of PoPLC-β1 also was affected by temperature and salinity stress. Our results provide clear evidence that the olive flounder PLC-β1 signal pathways may play a critical role in immune function at the cellular level and in inflammation reactions. In addition, PLC-β1 appears to act as an oxidative-stress suppressor to prevent cell damage in fish.