Evaluating the Aryl Hydrocarbon Receptor as a Target for Pharmacologic Activity of Repurposed Drugs

The discovery of new pharmacologic targets is important for the advancement of pharmacotherapy and identification of new indications for current drugs. The aryl hydrocarbon receptor (AHR) is a physiologic sensor of both chemical environmental pollutants and ligands of natural origin. Given the broad spectrum of ligands that activate the AHR and its relationship with toxicology, the AHR is not thought to be a traditional target for pharmacotherapy. However, multiple studies have shown potential for the AHR as a novel pharmacologic target Therefore, identifying less toxic agents that modulate the AHR may elucidate mechanisms for pharmacological targeting of the AHR. The hypothesis addressed for this thesis project is that chemical libraries of established drugs can be used to map the pharmacological space of the aryl hydrocarbon receptor. Three specific aims are proposed to address this hypothesis. Specific aim 1: Develop a high throughput screening assay to identify established drugs that activate the AHR. Specific aim 2: Use a chemical library of known pharmacologically active agents to map pharmacological space of the AHR and identify a lead compound for further evaluation. Specific aim 3: Determine chemical structure activity relationship of the lead compound’s pharmacophores and AHR activation potency. The AHR assay developed for Aim 1 incorporated an AHR-responsive green fluorescence protein (GFP) reporter that could be transduced into any cell type of interest. For normalization of transduction efficiency, a dtTomato expressing vector was optimized for expression without interference of the GFP reporter. Both the human colon cancer cell line Caco2 and the liver cancer cell line HepG2 were used in these studies. Drug screening for AHR activation using the AHR assay resulted in the identification multiple ligands including a lead compound. The lead compound in this study used for further evaluation was alpha-tocopherylquinone (TQ). The quinone structure is a critical component of TQ, interestingly other AHR ligands have been found to have a quinone structure as a molecular component. (eg dioxin) However, quinone structure ability to activate the AHR is less defined compared to other compounds like polycyclic carbons. In this study, differences were observed in the toxicity and AHR activation profile of fully substituted and unsubstituted para-quinones. The findings from these experiments suggest that there is a direct relationship between the number of carbon substitutions and the potency of the para-quinone to elicit an effect on the AHR. For example, we found that benzoquinone (BQ), an unsubstituted para-quinone was a relatively potent ligand of the AHR. Furthermore, adding a single methyl group to the benzoquinone increased its potency to activate the AHR. However, further methyl substitutions to the para-quinone ring diminished the para-quinone potency to activate the AHR. A compound that supported this observation was duroquinone, a fully substituted para-quinone which showed no AHR activity in the AHR assay. This study identifies critical characteristics necessary for para-quinones to activate the AHR and gives rise to a new class of compounds with potential of becoming novel treatments for disease through AHR activation

Measuring What Matters: How the Laboratory Contributes Value in the Opioid Crisis

With over 20 years of the opioid crisis, our collective response has evolved to address the ongoing needs related to the management of opioid use and opioid use disorder. There has been an increasing recognition of the need for standardized metrics to evaluate organizational management and stewardship. The clinical laboratory, with a wealth of objective and quantitative health information, is uniquely poised to support opioid stewardship and drive valuable metrics for opioid prescribing practices and opioid use disorder (OUD) management. To identify laboratory-related insights that support these patient populations, a collection of 5 independent institutions, under the umbrella of the Clinical Laboratory 2.0 movement, developed and prioritized metrics. Using a structured expert panel review, laboratory experts from 5 institutions assessed possible metrics as to their relative importance, usability, feasibility, and scientific acceptability based on the National Quality Forum criteria. A total of 37 metrics spanning the topics of pain and substance use disorder (SUD) management were developed with consideration of how laboratory insights can impact clinical care. Monitoring these metrics, in the form of summative reports, dashboards, or embedded in laboratory reports themselves may support the clinical care teams and health systems in addressing the opioid crisis. The clinical insights and standardized metrics derived from the clinical laboratory during the opioid crisis exemplifies the value proposition of clinical laboratories shifting into a more active role in the healthcare system. This increased participation by the clinical laboratories may improve patient safety and reduce healthcare costs related to OUD and pain management