The aryl hydrocarbon receptor (AhR) is a nuclear receptor that facilitates a wide transcriptional response and causes a variety of adaptive and maladaptive physiological functions. Such functions are entirely dependent on the type of ligand activating it, and therefore, the nuances in the activation of this receptor at the single-cell level have become a research interest for different pharmacological and toxicological applications. Here, we investigate the activation of the AhR by diverse classes of compounds in a Hepa1c1c7-based murine hepatoma cell line. The exogenous compounds analyzed produced different levels of ultrasensitivity in AhR activation as measured by XRE-coupled EGFP production and analyzed by both flow cytometric and computational simulation techniques. Interestingly, simulation experiments reported herein were able to reproduce and quantitate the natural single-cell stochasticity inherent to mammalian cell lines as well as the ligand-specific differences in ultrasensitivity. Classical AhR modulators 2,3,7,8-tetrachlorodibenzodioxin (10 − 1 -10 5 pM), PCB-126 (10 − 1 -10 7 pM), and benzo[a]pyrene (10 − 1 -10 7 pM) produced the greatest levels of single-cell ultrasensitivity and most maximal responses, while consumption-based ligands indole-3-carbinol (10 3 -10 9 pM), 3,3′-diindolylmethane (10 3 -10 8 pM), and cannabidiol (10 3 -10 8 pM) caused low-level AhR activation in more purely graded single-cell fashions. All compounds were tested and analyzed over a 24 h period for consistency. The comparative quantitative results for each compound are presented within. This study aids in defining the disparity between different types of AhR modulators that produce distinctly different physiological outcomes. In addition, the simulation tool developed for this study can be used in future studies to predict the quantitative effects of diverse types of AhR ligands in the context of pharmacological therapies or toxicological concerns.

Alzheimer’s disease (AD), typically characterized by the accumulation of the misfolded proteins Amyloid beta (Aβ1-42) and hyperphosphorylation of Tau (P-Tau), is the most common neurodegenerative disease. Although there is currently no cure, research with rodent models has found targeting the signaling pathways involved in reactive oxygen species (ROS) or the unfolded protein response (UPR) can diminish the toxic effects of AD (e.g., behavioral deficits, glial inflammation, and proteotoxicity). For this study, we hypothesized that treatment combining Cannabidiol (CBD) and Trazodone (TRA), would better mitigate neuronal dysfunction and extend the lifespan of nematodes engineered to aggregate toxic misfolded proteins. CBD and TRA have been individually found to diminish the deleterious effects of proteotoxicity in both in vivo and in vitro studies. The organisms utilized in the study included two strains of C. elegans genetically modified to express two pathological proteins of AD. Our experiments revealed that the motility and lifespan of C. elegans with proteotoxicity of either Aβ1-42 or P-tau were significantly improved by treatment with CBD and TRA in combination. We also confirmed aspects of existing research on the efficacy of CBD and TRA individually. Our data suggest that these benefits are seen with full-life, middle-age, and late-stage rescue utilizing CBD and TRA. These findings suggest the need for future experimentation incorporating CBD and TRA in treatment regiments in higher organisms, including neurodegenerative rodent models and aging canines with cognitive decline.