Differential effects of ocean warming and BDE-47 on mussels with various personalities.

Marine warming and polybrominated diphenyl ethers (PBDEs) pollution are two of the most concerning environmental problems in recent years. However, the impact of their co-occurrence on marine bivalves and the tolerance of bivalves with different traits remain unknown. In this study, thick shell mussels Mytilus coruscus were divided into two personalities according to individual feeding and byssus growth. The reliability of the classification was validated by respiration, self-organization, and post-stress behavior. Then, the survival rate, hemolymph immunity, and digestive glands oxidase activity of classified mussels were evaluated after 21 days of compound exposure to warming and BDE-47. The results showed that mussels could be divided into proactive and reactive types consistently. Compared to reactive mussels, proactive mussels exhibited some traits, such as faster food recovery, more byssus growth, higher metabolic rate, and more efficient clustering. Both single or combined warming and BDE-47 exposure impacted the individual survival, hemolymph, and antioxidase of mussels. Notably, the negative impacts of BDE-47 were exacerbated by warming. Moreover, proactive mussels displayed better adaptability with higher survival rates along with less damage to hemolymph immunity and antioxidant ability compared to reactive ones when facing environmental challenges. This study highlights potential risks associated with the coexistence of marine warming and PBDEs pollution while demonstrating differential fitness among individuals with distinct personalities.

Forsythoside A exerts an anti-endotoxin effect by blocking the LPS/TLR4 signaling pathway and inhibiting Tregs in vitro.

Endotoxins, also referred to as lipopolysaccharides (LPS), are powerful immunostimulators involved in a number of severe diseases. Forsythoside A (FTA), a monomer of phenethyl alcohol glycosides extracted from Forsythia suspensa, has been shown to possess anti-bacterial and immunomodulatory properties. However, it is currently not known whether FTA can counter the adverse effects of endotoxins. We investigated the effect of FTA on LPS-stimulated RAW264.7 cells and primary lymphocytes to determine its molecular mechanism of action. RAW264.7 cells and primary lymphocytes were incubated with or without LPS (100 ng/ml) in the presence or absence of FTA or polymyxin B. We found that FTA increased the viability of LPS-treated RAW264.7 cells and primary lymphocytes suggesting that FTA effectively counters the adverse effects of endotoxins. FTA decreased the percentage of regulatory T cells (Tregs) and inhibited the TLR4/MyD88/NF-κB signaling pathway, downregulating Foxp3, IL-10 and TGF-ß1, molecules involved in the immunosuppressive function of Tregs. These findings elucidate the molecular mechanism underlying the anti-endotoxin effects of FTA and suggest its use as a new treatment for LPS-induced diseases.