ABSTRACT
This proposal will address the critical need to define for cannabinoid exposure: 1) the most sensitive
developmental exposure windows; 2) the dose- and sex-dependence of adverse outcomes; 3)
developmentally relevant molecular mechanisms of persistent adverse effects; and 4) the relative
developmental toxicity of other cannabinoids available to consumers. Cannabis/∆9-tetrahydro-
cannabinol (THC) is the most commonly used illicit drug by pregnant women, and cannabidiol (CBD)
is readily available over the counter with suggested benefits in pregnancy for morning sickness, stress,
and sleeplessness. Similarly, other minor cannabinoids are marketed directly to consumers with
numerous health claims. Because of maternal use, pre- and post-natal cannabinoid exposures occur
during critical stages of children’s brain development despite our lack of understanding of the acute
and long-term consequences. In addition, cannabinoid exposure (e.g. via vaping) frequently occurs
during adolescence, another sensitive time of brain development and neuronal pruning. In our zebrafish
model system, we have observed persistently altered adult behavior after embryos were exposed to
THC and CBD during early development. Our central hypothesis is that exposure to cannabinoids
causes alterations in inflammatory mediators in the developing brain leading to the persistent
alterations in behavior throughout development and into adulthood. Our research framework, depicted
as an adverse outcome pathway (AOP), will specifically investigate three aims to measure: 1)
morphological and persistent behavioral alterations in anxiety/locomotion; 2) time-of-exposure
susceptibilities; and 3) neuroinflammation resulting from THC and CBD developmental exposure. We
will use the highly relevant, predictive, and high throughput zebrafish model, including three transgenic
lines, to assess the spatial and temporal relationships between microglial response, gene expression,
and persistent behavioral adverse outcomes. Cannabinoid-mediated changes in neuroinflammation
gene/protein expression and altered cellular trajectories will be identified using single nucleiRNAseq
and LC-MS/MS protein validation in larval and adult brains. The dependence of the specific cannabinoid
receptors in observed toxicities will be determined by using cannabinoid receptor 1 and 2 null lines.
Our ongoing and productive collaborations, including work with three NIH-COBRE core facilities, will
be leveraged to inform the developmental origins of health and disease caused by cannabinoid
exposure. The proposed research is significant because it will provide new, relevant information to
guide cannabinoid policy and healthcare decisions made by pediatricians, obstetricians, and policy-
makers needed to ensure public health and safety.
