Superfund Research Program
Superfund Chemicals, Nutrition, and Multi-Organ Cardiovascular Risk
Project Summary (2020-2025)
The overall goal of this project is to understand the signaling pathways and metabolic or biological changes by which bioactive nutrients modulate impacts of acute or chronic exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and long-chain per- and polyfluoroalkyl substances (PFAS). Such persistent pollutants express significant chemical stability in the environment, and toxic insults from POPs are known to correlate with a range of post-exposure human health impacts, including vascular inflammation. Atherosclerosis, a chronic inflammatory disease, remains the leading cause of death in the United States. Biological events associated with inflammation and atherosclerosis can be modified by circulating toxicants and bioactive nutrients and their metabolites, which dictate final redox changes and inflammatory outcomes, by altering NF-kB and Nrf2 signaling. For example, preliminary data demonstrate down-regulation of PCB 126-mediated toxicity and inflammation by plant-derived bioactive nutrients (e.g., polyphenols) and fiber (e.g., inulin). Importantly, it is known that the pathology of atherosclerosis is dependent on the health and crosstalk of multiple tertiary organ systems, including the liver and gut, as exemplified by recent findings linking PCB exposure with increased plasma levels of trimethylamine N-oxide (TMAO), a diet-derived metabolite formed through crosstalk between gut microbiota and hepatic oxidation and associated with risk of atherosclerosis. Preliminary findings indicate that persistent organic pollutants, and especially PCBs, cause liver dysfunction and alterations of gut microbiota and that prior liver injury exacerbated PCB-mediated systemic inflammation. Metabolomic profiling further suggested that increased formation of pro-atherogenic metabolites (e.g., ceramides) may drive multi-organ inflammation and increased cardiovascular risk. Based on these findings, three specific aims test the hypotheses that:
- Administration of PCB 126 and/or PFAS to mice increases cardiometabolic disease risk by increasing ceramide production via modulation of hepatic gene expression and/or the gut microbiota;
- Administration of green tea catechins and/or soluble inulin fiber in vivo decreases ceramides and thereby stabilizes cellular redox status, modulating NF-kB and Nrf2 signaling and proatherosclerotic pathologies as determined by en face and lipid staining in atherogenic LDL receptor-deficient mice; and
- Exposure to PCBs and/or PFAS increases pro-atherogenic metabolites (e.g., ceramides) through increased de novo synthesis in preclinical models.
Project researchers use transcriptomic and metabolomic technologies to explore the mechanistic interactions between pollutant exposure, nutritional intervention, and cardiovascular disease (CVD) risks. They confirm these data in biobanked samples of humans with CVD. The results will support the paradigm that healthful nutrition interventions offer a powerful strategy to reduce disease risks associated with environmental toxic insults and to prevent inflammatory diseases, such as atherosclerosis, that have been linked to exposure to Superfund pollutants.