Activation of Type 1 Cannabinoid Receptor (CB1R) Promotes Neurogenesis in Murine Subventricular Zone Cell Cultures

Abstract

The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+]i) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.

ACEA (a highly selective cannabinoid CB1 receptor agonist) stimulates hippocampal neurogenesis in mice treated with antiepileptic drugs

“…Findings that CB1 activation strongly promotes neuronal maturation and complexity might suggest that endocannabinoid system participate in the formation of new neuronal circuits in the developing brain or as a consequence of brain injury. Similarly, results from the studies on CB1 receptor using murine subventricular zone (SVZ) cell cultures indicated that activation of CB1 receptors has a pro-neurogenic effect on SVZ cells, suggesting that this pathway may be modulated in order to activate neurogenesis in SVZ cells (Xapelli et al, 2013).…”

Methamphetamine decreases dentate gyrus stem cell self-renewal and shifts the differentiation towards neuronal fate

“…Taking advantage of these properties, we analyzed if METH interferes with cell-fate division. For that, cell pair assay was performed as previously described Santos et al, 2012;Xapelli et al, 2013) with some modifications. Hence, stem cells were directly isolated from mice DG and 10,000 cells (8840 cells/cm 2 ) were plated onto poly-D-lysine-coated (SigmaAldrich) glass coverslips.…”

Neuroimmmune interactions of cannabinoids in neurogenesis: focus on interleukin-1β (IL-1β) signalling

“…Cannabinoids also control differentiation in the hippocampus, although the effects are still in debate: some results suggest that metanandamide, a CB 1 receptor agonist, induces neurogenesis in vitro [30] and CB 1 receptor absence impairs maturation of new neurons in vivo [29]. Other studies show that cannabinoids inhibit neuronal differentiation and induce astroglial differentiation in vitro and in vivo [28].…”

“…Similarly, methanandamide, through CB1 receptors, promotes proliferation and selfrenewal of SVZ-derived NSCs, although long-term treatment stimulates functional neuronal differentiation [30]. In the SVZ, NSCs may secrete the endocannabinoid anandamide [32].…”