Data_Sheet_1_2-Arachidonoylglycerol as an Endogenous Cue Negatively Regulates Attachment of the Mussel Perna viridis.PDF

Endocannabinoids play important roles in the functioning of various physiological systems in humans and non-mammalian animals, including invertebrates. However, information concerning their roles in physiological functions in members of the phylum Mollusca is scarce. Here the hypothesis that the endocannabinoids are involved in mediating settlement of marine invertebrates was tested. Two endocannabinoids [N-arachidonoyl ethanolamide (AEA) and 2-arachidonoyl glycerol (2-AG)], and two endocannabinoid-like lipids [N-Oleoylethanolamide (OEA) and N-Palmitoylethanolamide (PEA)] were detected in the green mussel Perna viridis. In particular, 2-AG was present at significantly higher levels in unattached P. viridis compared with attached mussels. The in vivo level of 2-AG was inversely correlated with the attachment activity of P. viridis. Furthermore, exposure to synthetic 2-AG inhibited attachment of P. viridis in a reversible manner. Transcriptomic analysis suggested that up-regulation of 2-AG synthase (Phospholipase C-β, PLC-β) and down-regulation of its degrading enzyme (Monoacylglycerol lipase, MAGL) resulted in higher levels of 2-AG in unattached mussels. A putative mechanism for the negative regulation of mussel attachment by 2-AG is proposed that involves a Ca2+- Nitric oxide (NO)- cyclic guanosine monophosphate (cGMP) pathway. This study broadens our understanding of the evolution and roles of the endocannabinoid system in animals, and reveals an endogenous regulatory cue for mussel attachment.

内源大麻素在人类及非哺乳动物各种生理系统中发挥着重要作用，包括无脊椎动物。然而，关于它们在软体动物门成员生理功能中的角色信息却相对匮乏。本研究旨在检验内源大麻素是否参与调节海洋无脊椎动物的定居。在绿贻贝Perna viridis中检测到了两种内源大麻素[N-花生四烯酰乙醇胺（AEA）和2-花生四烯酰甘油（2-AG）]，以及两种内源大麻素样脂质[N-油酸乙乙醇胺（OEA）和N-棕榈酸乙乙醇胺（PEA）]。特别是，与附着贻贝相比，未附着贻贝中的2-AG含量显著更高。体内2-AG水平与P. viridis的附着活性呈负相关。此外，接触合成2-AG以可逆方式抑制了P. viridis的附着。转录组分析表明，2-AG合酶（磷脂酰肌醇特异性磷脂酶C-β，PLC-β）的上调和其降解酶（单酰甘油酯脂肪酶，MAGL）的下调导致了未附着贻贝中2-AG水平的升高。提出了一种关于2-AG通过Ca2+-一氧化氮（NO）-环磷酸鸟苷单磷酸（cGMP）途径负调控贻贝附着的作用机制。本研究拓展了我们对动物内源大麻素系统进化及其功能的理解，并揭示了调节贻贝附着的内源性调控信号。