Date of Award
5-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Environmental Toxicology
Committee Chair/Advisor
Dr. William Baldwin
Committee Member
Dr. Lisa Bain
Committee Member
Dr. Subham Dasgupta
Abstract
The Environmental Influences on Child Health Outcomes Fetal Growth Studies (ECHO-FGS) birth cohort data was used to identify chemical mixtures associated with adverse outcomes. This biomonitoring study associated specific chemical mixtures in maternal serum with low birth weight or childhood obesity (Pearce et al., 2021). Mixture Profiles 1, 3, and 4, comprised of different observed concentrations of DDE, PCB153, BDE47, and PFOS were prioritized. Mixtures were tested to determine whether they perturbed mitochondrial metabolism and energy sensing pathways. The purpose of this study was to elucidate a potential mechanism linking maternal exposure to mixtures containing persistent organic pollutants (POPs) to adverse childhood health outcomes, such as low birth weight or childhood obesity.
To investigate whether mixtures perturb mitochondrial metabolism, mixture profiles 1, 3, and 4 were examined at environmentally observed concentrations (1X) and greater (50X, 250X, 500X). Mitochondrial metabolism was measured as Oxygen Consumption Rate (OCR) 1-hour and 24-hours after exposure in C2C12 murine myoblast and HepG2 human hepatocarcinoma cells using Mito Stress Tests on an Agilent Seahorse XFe24 Analyzer (Agilent Technologies, Santa Clara, CA). Mito Stress assays performed in C2C12 cells revealed that environmentally relevant mixtures of POPs perturb mitochondrial function, including basal and ATP-coupled respiration. To determine chemical interactions, mitochondrial metabolism was measured in C2C12 cells 1-hour after exposure to individual chemicals, two or three chemical combinations, and compared to the full four chemical mixtures. Mito Stress assays indicate the dominant chemicals in Profile 1 (DDE) and Profile 3 (BDE47) drive the observed metabolic effects. However, the mitochondrial effects of PFOS, the dominant chemical in Profile 4, are antagonized by PCB153 causing a mixture interaction. These data demonstrate that mixture-induced mitochondrial effects can be shaped by individual chemicals and mixture composition.
To evaluate potential interactions of altered mitochondrial function, KEGG Pathway analysis revealed PCB153 and PFOS alter the AMPK pathway. Further evaluation of 1 hour exposure of Profiles 1, 3, and 4 at 1X shows decreased pAMPK quantified by an Enzyme-Linked Immunosorbent Assay (ELISA) and confirmed by immunoblotting. These data demonstrate that mixtures can alter the activation of cellular energy sensing proteins vital for energy homeostasis.
In conclusion, environmentally relevant concentrations of mixtures induce mitochondrial and catabolic pathway perturbations in C2C12 myoblasts. These findings highlight mitochondria and AMPK as potentially sensitive targets of chemical mixtures. Results suggest that perturbation of mitochondrial functions and the AMPK Pathway may be a mechanistic link between real-world exposure to POP mixtures leading to metabolic dysregulation relevant to adverse child health outcomes.
Recommended Citation
Jacobellis, Morgan, "Disruption of Energy Homeostasis by Chemical Mixtures Containing Persistent Pollutants in HepG2 and C2C12 Cells" (2026). All Theses. 4692.
https://open.clemson.edu/all_theses/4692
Author ORCID Identifier
0000-0002-6656-3899