Prenatal cannabis use is associated with altered miRNA and protein expression in the developing human brain

Background: Cannabis is widely used during pregnancy, increasing with cannabis legalization, and has been associated with altered neurodevelopment, yet the precise molecular mechanisms remain poorly understood.

Aims: To assess whether utilizing fetal central nervous system-derived extracellular vesicles (fCNSEVs) isolated from maternal blood reflects cannabisassociated changes in the fetal brain.

Methods: In a matched case-control study, maternal plasma (to isolate fCNSEVs) and paired fetal cortical tissue (9–18weeks’ gestation) from pregnancies exposed or unexposed to cannabis were collected. We quantified protein (CB1R, D2R) and miRNA expression (using µ-parafloTM microarray). Selected miRNAs were validated by qPCR. Bayesian Generalized Linear Models were used to assess exposure-group by sex effects.

Results: Maternal cannabis use was associated with altered CB1R and D2R levels in the brain with opposite directional changes in fCNSEVs. 21 miRNAs were differentially expressed: 14 downregulated and 6 upregulated, following a sex-dependent pattern (males>>females), while miR-216a-5p follows the opposite pattern (females>>males). We confirmed concordant miRNA changes in fetal brain and fCNSEVs. Many of the identified molecules are associated with pathways linked to adverse neurodevelopmental outcomes.

Conclusions: Our data suggest that fCNSEV-based assays may provide the ability to monitor fetal brain effects of maternal cannabis in ongoing pregnancies in clinical cohorts. A critical next step is to determine if alterations in fCNSEV protein and miRNA markers predict changes in fetal brain connectivity and neurodevelopment measures of executive function.

prenatal cannabis exposure, neurodevelopment, CNS-derived extracellular vesicles