Lysine acetylation in the allograft-induced stress response of Pinctada fucata martensii

The pearl oyster, Pinctada fucata martensii, can experience transplant rejection or even host death following allografting. This study investigated the impact of increased protein acetylation on the immune response of P. fucata martensii after implantation, aiming to elucidate the role of acetylation modifications in this process. A mixture of broad-spectrum lysine deacetylase inhibitors (KDI) was injected into P. fucata martensii to assess the effects of increased protein acetylation using multiple analytical methods, including quantitative real-time PCR (qRT-PCR), Western blot (WB), antioxidant enzyme activity assay, and culture indicators. Following KDI injection, the relative expression of HDAC 6/10 (10006221), and two mumbers of the Sir2 family (10031932 and 10020349) were significantly down-regulated at different time points. Meanwhile, the acetylation level of total proteins in the gills was significantly increased at 72 h, indicating enhanced protein acetylation in gill tissue. Additionally, the expression of IRAK1, IL-17, NF-κB, and CASP2 were significantly up-regulated at 12 h, while IκK was significantly up-regulated at 48 h. In contrast, TRAF3 expression was significantly down-regulated from 48 h onward, suggesting that KDI stimulation enhanced cellular immunity in recipient oysters. Furthermore, antioxidant enzymes such as GSH-Px, POD, and CAT were significantly up-regulated at 12 and 24 h post-KDI treatment, indicating enhanced humoral immunity. The retention and survival rates of oysters were significantly higher at 60 d post-KDI treatment compared to the control group. These results suggested that acetylation modifications play a key role in allograft-induced stress in P. fucata martensii, and KDI may serve as immunomodulator to regulate the implantation process. In summary, this study provided an important basis for exploring the immune response and adaptive mechanisms associated with acetylation modifications in P. fucata martensii during implantation, and offered theoretical support for the rational control of the immune response in P. fucata martensii.