The interaction between cannabis use and a CB1-related polygenic co-expression index modulates dorsolateral prefrontal activity during working memory processing
BRAIN IMAGING AND BEHAVIOR
Authors: Taurisano, Paolo; Pergola, Giulio; Monda, Anna; Antonucci, Linda A.; Carlo, Pasquale Di; Piarulli, Francesco; Passiatore, Roberta; Papalino, Marco; Romano, Raffaella; Monaco, Alfonso; Rampino, Antonio; Bonvino, Aurora; Porcelli, Annamaria; Popolizio, Teresa; Bellotti, Roberto; Bertolino, Alessandro; Blasi, Giuseppe
Abstract
Convergent findings indicate that cannabis use and variation in the cannabinoid CB1 receptor coding gene (CNR1) modulate prefrontal function during working memory (WM). Other results also suggest that cannabis modifies the physiological relationship between genetically induced expression of CNR1 and prefrontal WM processing. However, it is possible that cannabis exerts its modifying effect on prefrontal physiology by interacting with complex molecular ensembles co-regulated with CB1. Since co-regulated genes are likely co-expressed, we investigated how genetically predicted co-expression of a molecular network including CNR1 interacts with cannabis use in modulating WM processing in humans. Using post-mortem human prefrontal data, we first computed a polygenic score (CNR1-PCI), combining the effects of single nucleotide polymorphisms (SNPs) on co-expression of a cohesive gene set including CNR1, and positively correlated with such co-expression. Then, in an in vivo study, we computed CNR1-PCI in 88 cannabis users and 147 non-users and investigated its interaction with cannabis use on brain activity during WM. Results revealed an interaction between cannabis use and CNR1-PCI in the dorsolateral prefrontal cortex (DLPFC), with a positive relationship between CNR1-PCI and DLPFC activity in cannabis users and a negative relationship in non-users. Furthermore, DLPFC activity in cannabis users was positively correlated with the frequency of cannabis use. Taken together, our results suggest that co-expression of a CNR1-related network predicts WM-related prefrontal activation as a function of cannabis use. Furthermore, they offer novel insights into the biological mechanisms associated with the use of cannabis.
Reduced expression of brain cannabinoid receptor 1 (Cnr1) is coupled with an increased complementary micro-RNA (miR-26b) in a mouse model of fetal alcohol spectrum disorders
CLINICAL EPIGENETICS
Authors: Stringer, Randa L.; Laufer, Benjamin I.; Kleiber, Morgan L.; Singh, Shiva M.
Abstract
Background: Prenatal alcohol exposure is known to result in fetal alcohol spectrum disorders, a continuum of physiological, behavioural, and cognitive phenotypes that include increased risk for anxiety and learning-associated disorders. Prenatal alcohol exposure results in life-long disorders that may manifest in part through the induction of long-term gene expression changes, potentially maintained through epigenetic mechanisms. Findings: Here we report a decrease in the expression of Canabinoid receptor 1 (Cnr1) and an increase in the expression of the regulatory microRNA miR-26b in the brains of adult mice exposed to ethanol during neurodevelopment. Furthermore, we show that miR-26b has significant complementarity to the 3'-UTR of the Cnr1 transcript, giving it the potential to bind and reduce the level of Cnr1 expression. Conclusions: These findings elucidate a mechanism through which some genes show long-term altered expression following prenatal alcohol exposure, leading to persistent alterations to cognitive function and behavioural phenotypes observed in fetal alcohol spectrum disorders.