Proteomics Reveals Divergent Cardiac Inflammatory and Metabolic Responses After Inhalation of Ambient Particulate Matter With or Without Ozone

Inhalation of ambient particulate matter (PM) and ozone (O-3) has been associated with increased cardiovascular morbidity and mortality. However, the interactive effects of PM and O-3 on cardiac dysfunction and disease have not been thoroughly examined, especially at a proteomic level. The purpose of this study was to identify and compare proteome changes in spontaneously hypertensive (SH) rats co-exposed to concentrated ambient particulates (CAPs) and O-3, with a focus on investigating inflammatory and metabolic pathways, which are the two major ones implicated in the pathophysiology of cardiac dysfunction. For this, we measured and compared changes in expression status of 9 critical pro- and anti-inflammatory cytokines using multiplexed ELISA and 450 metabolic proteins involved in ATP production, oxidative phosphorylation, cytoskeletal organization, and stress response using two-dimensional electrophoresis (2-DE) and mass spectrometry (MS) in cardiac tissue of SH rats exposed to CAPs alone, O-3 alone, and CAPs + O-3. Proteomic expression profiling revealed that CAPs alone, O-3 alone, and CAPs + O-3 differentially altered protein expression patterns, and utilized divergent mechanisms to affect inflammatory and metabolic pathways and responses. Ingenuity Pathway Analysis (IPA) of the proteomic data demonstrated that the metabolic protein network centered by gap junction alpha-1 protein (GJA 1) was interconnected with the inflammatory cytokine network centered by nuclear factor kappa beta (NF-kB) potentially suggesting inflammation-induced alterations in metabolic pathways, or vice versa, collectively contributing to the development of cardiac dysfunction in response to CAPs and O-3 exposure. These findings may enhance understanding of the pathophysiology of cardiac dysfunction induced by air pollution and provide testable hypotheses regarding mechanisms of action.