Utilizing early cellular changes to explore biological responses to individual chemical and mixture exposures

Abstract

Utilizing early cellular changes to explore biological responses to individual chemical and mixture exposures by Julie Anne Vrana Humans are continuously exposed to a vast number of chemicals, whether it be from the air we breathe, the water we drink, or the medications we take daily. Early cellular changes after exposure to chemical insult, both individual chemicals and mixtures (two or more chemicals) thereof, can offer a wealth of information about cellular adaptation (e.g., cell death or survival decision processes). From this understanding, better prediction models for chemical risk assessment, such as toxicity or carcinogenicity, can be elucidated. Further, these prediction models can greatly improve the large backlog of chemicals waiting to be evaluated for potential adverse effects. One approach to understand cellular changes and responses after chemical or mixture exposure is with toxicodynamics. From a toxicodynamic approach, a host of information can be determined, such as spatiotemporal interactions of chemical insult with biological targets, the corresponding disruption of intracellular pathways and bioenergetics, and downstream effects after exposure. Appropriately measuring these dynamic cellular changes is imperative. The recent advances in molecular biology, high-throughput in vitro screening assays, and numerous computational techniques have allowed toxicologists to collect large data sets on signaling pathways that are perturbed in response to chemical insults. From these early cellular perturbations, whether they be signaling proteins, biomolecules (e.g., ATP, hormones, NADH), or ions (e.g., Ca 2+ or K +), in response to a wide range of doses, especially low concentrations, improved risk assessment prediction models for individual chemical and mixture exposures can be utilized by many fields, such as risk assessment for environmental toxicology and target molecule/pathway analysis for drug development and pharmacology. iii DEDICATION This dissertation is dedicated to the memory of my extraordinary grandparents, Paul and Julia Ondrasik and Charles and Rosalie Vrana, and my remarkable cousin, Ashley Baker. Each of these individuals inspired me through their tireless work ethic, appreciation of life and little moments, wisdom, sense of humor, and endless love of family and friends. relative phosphorylation during critical signaling events 3.3.2 Forecasting mixtures dose-response with hierarchical cluster 91 analysis 3.4 Discussion 3.5 References Appendix 3.1 Observed relative phosphorylation of deguelin and KCN 100 mixtures (400 min post-exposure) Appendix 3.2 Observed relative phosphorylation of MEK inh II and 105 TDZD-8 mixtures (20 min post-exposure) Appendix 3.3 Observed relative phosphorylation of MEK inh II and 111 TDZD-8 mixtures (40 min post-exposure 4. Using mixtures to ameliorate undesired side-effects of deguelin 4.1 Introduction 4.2 Materials and Methods 4.2.1 Materials 4.2.2 Cell culture 4.2.3 Dosimetry 4.2.4 MTT assay ix 4.2.5 Oxygen consumption assay 4.2.6 Bio-plex multiplex immuno...