Evidence of cannabinoid modulation in nuclear signaling

GAVEGLIO, V.L.; GIUSTO, N.M.; PASQUARÉ, S.J.

Mar del Plata

Congreso; LXIV Reunión Anual SAIC; 2019

SAIC

The endocannabinoid system (ECS) is a signaling mechanism involved in many pathophysiological processes, especially in the nervous system. Former studies from our lab demonstrated the presence of the different components of the ECS in nuclei from rat cerebellum and cerebral cortex (CC). We detected diacylglycerol lipase and monoacylglycerol lipase activities which are involved in maintaining the levels of the endocannabinoid 2-arachidonoyl-glycerol. In addition, we demonstrated a nuclear CB1 protein expression by Western Blot and immunocytochemistry. CB1 is a GPCR receptor that triggers different signaling cascades, modulating intracellular Ca2+ levels, ERK1/2 phosphorylation, and other second messengers at the plasma membrane. Nevertheless, we also observed an increase in ERK phosphorylation in isolated nuclei from rat cerebral cortex (CCN) incubated with a CB1 synthetic agonist (WIN 55-212-2). Phosphorylated ERK could be involved in activating MSK1/2, a nuclear kinase that phosphorylates histone 3 (H3). The aim of this work was therefore to study how a cannabinoid agonist modulates ERK1/2 and H3 phosphorylation in CCN. To this end, CC from Wistar rats were dissected and homogenized, and highly purified nuclei (CCN) were isolated on a sucrose-density ultracentrifugation. CCN were subsequently incubated at 37 °C with WIN and ERK1/2 and H3 signaling cascades were studied by Western Blot. Interestingly, it was observed that ERK1/2 and H3 phosphorylation increased in nuclei treated with WIN 5 µM for 30 min with respect to controls (p