The endocannabinoid anandamide induces apoptosis of rat decidual cells through a mechanism involving ceramide synthesis and p38 MAPK activation

Abstract

Anandamide (AEA) belongs to an endogenous family of lipid messengers, called endocannabinoids (ECs), which exert pharmacological effects by binding to selective membrane receptors, the CB1 and CB2 receptors. Increasing evidence suggests that AEA is involved in the regulation of a variety of cell signalling pathways both in experimental models and humans. We have previously demonstrated that ECs machinery operates in decidual cells and found that AEA, the principal EC, induced apoptosis in decidual cells through CB1. Here, we investigated in rat primary decidual cells the signal transduction pathways activated upon AEA binding to CB1. We found that AEA induces a significant increase in the level of intracellular ceramide. These effects were reversed by inhibiting CB1 receptor activation with AM251. The ceramide analogue, C6-ceramide, induced a decrease in decidual cell viability and of p38 MAPK phosphorylation. Additionally, the pharmacologic inhibition of de novo ceramide biosynthesis with L-cycloserine and fumonisin B reduced the AEA-effects on cell viability and p38 MAPK phosphorylation. Furthermore, AEA and C6-ceramide induced a drop in ΔΨm, an increase in ROS production and caspase-3/-7 activation, effects partially reverted by inhibitors of ceramide synthesis and of p38 MAPK. Taken together, we showed that AEA induces a reduction in decidual cell viability by a mechanism involving CB1 activation, which results in ceramide synthesis de novo and p38 phosphorylation, followed by mitochondrial stress and ROS production, leading to apoptosis.

Anandamide restricts uterine stromal differentiation and is critical for complete decidualization

“…During early gestation, successful embryo passage through the oviduct and implantation into the uterus require critical enzymatic control of the endocannabinoid levels . We have previously described that AEA induces apoptosis of decidual cells, effects dependent on CB1 activation, involving p38 phosphorylation and a drop in the mitochondrial membrane potential (Fonseca et al, 2009(Fonseca et al, , 2013. Here, we provide evidence that AEA is able to inhibit the in vitro and in vivo process of stromal cell differentiation.…”

“…The major endocannabinoid, anandamide (AEA), besides widely distributed in the body, is present in high amounts in the reproductive tissues and is a relevant mediator synchronizing embryo development, transport and implantation (Karasu et al, 2011). Additionally it was demonstrated that AEA induces decidual cell apoptosis through CB1 receptor, involving this molecule in maternal tissue remodeling in the fetoplacental unit (Fonseca et al, 2009(Fonseca et al, , 2013.…”

Mitochondria: a possible nexus for the regulation of energy homeostasis by the endocannabinoid system?

“…For example, both plant-derived and synthetic cannabinoid receptor agonists, as well as AEA and 2-AG, have been shown to stimulate mitochondrial ROS generation, which, in turn, may impact negatively on electron transport activity as well as promoting cytochrome c release (4,43,129,160). Interestingly, a study by Fonseca et al (43) suggested that ECS-induced generation of ROS may be driven by increased ceramide synthesis. However, whether ROS derived from mitochondria or from an alternative subcellular source is responsible for perturbing mitochondrial respiratory function by the ECS remains unclear.…”

The Endocannabinoid System in the Postimplantation Period: A Role during Decidualization and Placentation

“…Also, the activation of CB1 results in ceramide synthesis de novo and p38 phosphorylation, followed by induction of mitochondrial stress and ROS production, leading to apoptosis (Figure 2) [70]. Moreover, methyl- β -cyclodextrin (MCD), a cholesterol membrane depletor, has no effects on AEA/2-AG-programmed cell death [52, 69].…”