Uncovering a role for endocannabinoid signaling in autophagy in preimplantation mouse embryos

Abstract

Endocannabinoid signaling plays various roles in directing reproductive processes. Mouse embryos are shown to express high levels of CB1 receptor (CB1R). Low concentrations of anandamide stimulate embryo growth and implantation but at higher concentrations it adversely affects implantation. We tested the hypothesis that high levels of endocannabinoids cause autophagic activation and cell death in preimplantation mouse embryos. We used methanandamide (METH), a selective CB1R agonist, to examine the effect of heightened endocannabinoid signaling on autophagy in mouse embryos. Western blotting, immunofluorescence staining, transmission electron microscopy and TUNEL analysis were performed. We observed that METH treatment in vitro or in vivo up-regulated autophagic response in preimplantation mouse embryos. In blastocysts, apoptosis was also increased after METH injections. At 28 nM, which is considered a high physiological dose to embryonic cells, METH up-regulated autophagic activation in trophoblast stem cells. This work demonstrates for the first time that blastocysts respond to higher than normal levels of endocannabinoid by increasing autophagic activation and apoptosis.

Interplay of oxidative, nitrosative/nitrative stress, inflammation, cell death and autophagy in diabetic cardiomyopathy

“…Pharmacological inhibition or genetic deletion of CB 1 receptors was associated with attenuated diabetes-induced myocardial inflammation, decreased MAPK activation, oxidative/nitrative stress, β-MHC isoenzyme switch, AT 1 R up-regulation, myocardial RAGE and AGE expression/accumulation, MAPK activation, and largely diminished cell death and better preservation of cardiac function [38]. Recent studies indicate that cannabinoids (especially CB1 agonists) may be important inductors of autophagy in preimplantation mouse embryos [138] and in human epithelial colorectal adenocarcinoma cells (CaCo2) [139]. Although, the evidences outlined here clearly show that inflammation is one of the key therapeutically important components associated with diabetic cardiomyopathy, to see if pharmacologic modulation of cytokine as well as cannabinoid signalling and thereby autophagy has therapeutic potential, further experimental studies are required.…”

Neuronal substrates and functional consequences of prenatal cannabis exposure

“…CB 1 R mRNA has been detected as early as the preimplantation period [74] and is involved in embryo implantation [75], embryonic growth [36] and neuronal development [76]. In the developing central nervous system of rodents, CB 1 R mRNA and receptor density gradually increase during foetal development [77, 78] from day 11 of gestation (comparable to 5/6 weeks in the human embryo).…”

Suppression of autophagic activation in the mouse uterus by estrogen and progesterone

“…Protein extraction and western blotting were carried out as described previously (Oh et al 2013). Uteri were removed at the indicated times and the protein extraction was carried out in lysis buffer (10 mM Tris (pH 7.2), 150 mM NaCl, 0.1% Triton X-100, 5 mM EDTA, 1% SDS, 1 mM dithiothreitol (DTT), and 1 mM phenylmethylsulphonyl fluoride (PMSF)).…”

“…In preimplantation mouse embryos, endocannabinoids are established inducers of autophagy (Oh et al 2013). In human endometrial cells, autophagy seems to be involved in the cell cycle (Choi et al 2012).…”