| Summary: |
The intense research into Cannabis sativa medicinal properties and the recent changes in legislation led to an increase in the prescription of cannabinoid medicines. These contain high concentrations of delta-9-tetrahydrocannabinol (THC) the main psychoactive compound of cannabis. However, data are limited regarding adverse events and safety. Cannabinoid actions are mediated by activation of cannabinoid receptors CB1 and CB2. Interestingly, these receptors can also be activated by endogenous cannabinoids produced in mammalian tissues, the endocannabinoids (eCBs). The first eCBs discovered were Narachidonoyl ethanolamine (anandamide; AEA) and 2arachidonoyl glycerol (2AG).
These novel lipid mediators are essentially synthesised from membrane phospholipids, activate CBs receptors and are degraded. Thus, the endocannabinoid system (ECS) is constituted by eCBs, their metabolic enzymes and CB receptors. Endocannabinoid signalling plays key roles in regulating multiple biological functions, including synaptic plasticity, pain modulation, energy homeostasis and reproduction. The growing list of disorders in which the ECS is involved has provided the possibility of developing medicines that will activate or block the
system, helping to identify new therapeutic uses. Nevertheless, the potential for modulators of the ECS to induce both beneficial
and harmful effects needs to be studied. Moreover, exposure to the exocannabinoids either by recreational or medicinal use may alter eCBs levels with possible consequences for the biological functions of the ECS. In fact, THC administration to healthy volunteers resulted in higher circulating levels of AEA and 2AG when compared with placebo. Thus, exogenous cannabinoids
may interfere with synthesis and degradation of eCBs in several tissues namely in reproductive tissues inducing adverse effects in the reproductive male and female health. We will test this hypothesis in the trophoblast cells of the placenta, a target for  |
Summary
The intense research into Cannabis sativa medicinal properties and the recent changes in legislation led to an increase in the prescription of cannabinoid medicines. These contain high concentrations of delta-9-tetrahydrocannabinol (THC) the main psychoactive compound of cannabis. However, data are limited regarding adverse events and safety. Cannabinoid actions are mediated by activation of cannabinoid receptors CB1 and CB2. Interestingly, these receptors can also be activated by endogenous cannabinoids produced in mammalian tissues, the endocannabinoids (eCBs). The first eCBs discovered were Narachidonoyl ethanolamine (anandamide; AEA) and 2arachidonoyl glycerol (2AG).
These novel lipid mediators are essentially synthesised from membrane phospholipids, activate CBs receptors and are degraded. Thus, the endocannabinoid system (ECS) is constituted by eCBs, their metabolic enzymes and CB receptors. Endocannabinoid signalling plays key roles in regulating multiple biological functions, including synaptic plasticity, pain modulation, energy homeostasis and reproduction. The growing list of disorders in which the ECS is involved has provided the possibility of developing medicines that will activate or block the
system, helping to identify new therapeutic uses. Nevertheless, the potential for modulators of the ECS to induce both beneficial
and harmful effects needs to be studied. Moreover, exposure to the exocannabinoids either by recreational or medicinal use may alter eCBs levels with possible consequences for the biological functions of the ECS. In fact, THC administration to healthy volunteers resulted in higher circulating levels of AEA and 2AG when compared with placebo. Thus, exogenous cannabinoids
may interfere with synthesis and degradation of eCBs in several tissues namely in reproductive tissues inducing adverse effects in the reproductive male and female health. We will test this hypothesis in the trophoblast cells of the placenta, a target for eCBs action as placenta is one of the organs known to be affected by cannabinoids consumption. Besides being associated with alterations in sperm viability and motility, cannabis use is linked to spontaneous miscarriages, fetal growth restriction and preterm birth. These effects are attributed to the actions of THC but, in fact, the molecular mechanisms underlying these effects are unknown. Interestingly, levels of AEA decrease progressively throughout gestation suggesting that a tight control of eCBs levels is required for normal pregnancy progression. Therefore, exposure to exocannabinoids may lead to inappropriate activation of the CB receptor mediated pathways interfering with the ECS homeostasis. One of the aims of this proposal is to measure in trophoblasts, the eCBs levels by LCMS/MS, and analyse the expression and activities of the metabolic enzymes responsible for local tissue regulation in response to THC treatment.
During the period of placental development, a tightly regulated tissue remodelling occurs, involving proliferation, apoptosis, differentiation and invasion of trophoblasts. We demonstrated that eCBs induce cytotrophoblast (CTs) apoptosis and impair their differentiation into syncytiotrophoblast (ST) affecting the synthesis of important hormones such as human chorionic gonadotropin (hCG) and leptin. In addition, our preliminary studies suggest that THC affects trophoblast differentiation. By using
CTs primary cultures we will get further insights on the impact of exocannabinoids in the processes of cell death and differentiation and the signalling pathways involved. Additionally, by analysing the hormones that affect maternal and fetal metabolism, we will determine the role of eCBs in hormone regulation in order to understand the contribution of exocannabinoids in pathophysiology.
One of the trophoblast subtypes, the extravillous trophoblasts type (EVTs) has tumourlike properties that promote a tight regulated invasion of uterine tissues and vessels by growth factors, hormones and proteases within the trophoblastendometrial microenvironment. On the other hand, it was described that eCBs have antiinvasive effects on tumour cells, suggesting a role in cell invasion. Nevertheless, the role of ECS in trophoblast invasion is largely unexplored. We propose to study the effects of AEA and 2AG and of the phytocannabinoid THC in trophoblast invasion, exploring the triggered signalling pathways.
This proposal will contribute to the understanding of the impact of cannabinoids consumption in the endocannabinoid signalling within the dynamics of tissue turnover in the maternal fetal interface, providing valuable information for managing pregnancy related diseases and infertility. This work also contributes to the public debate about the risk/benefits of cannabis based medicines. |