Gene expression of diesel exhaust inhalation in peripheral blood mononuclear cells from healthy human volunteers

Background: Diesel exhaust (DE) is the primary source of urban fine particulate matter, which has been associated with cardiovascular disease in epidemiological studies. These effects may be related to oxidative stress and systemic inflammation with resulting perturbation of vascular homeostasis. Peripheral leukocytes are involved in both inflammation and control of vascular homeostasis. Objectives: We conducted an exploratory study using microarray techniques to analyze whether global gene expression in peripheral blood mononuclear cells (PBMCs) can inform on potential mechanisms of effect of DE inhalation. Methods: In a double-blind, crossover, controlled exposure study, healthy adult volunteers were exposed in randomized order to filtered air (FA) and diluted DE in two-hour sessions. We isolated RNA (Trizol/Qiagen method) form PBMCs before, and two times after each exposure. RNA samples were arrayed using the Affymetrix platform (GeneChip Human Genome U133 Plus 2.0 Array). Results: Microarray analyses were conducted on five subjects with available RNA sample form exposures to FA and to the highest DE inhalation (200 g/m of fine particulate matter). Following data normalization and statistical analysis, a total of 1290 out of 54,675 probe sets with significant evidence for differential expression (more than 1.5-fold up or down regulated with p < 0.05) were identified. These include genes involved in inflammatory response (e.g., IL8RA, TNFAIP6, FOS), oxidative stress (e.g., HMOX1, BAX, PRDX1,), and in biochemical pathways like mitogen-activated protein kinases (MAPK) and tight junction pathways. Conclusions: These data suggest that DE may exert time-dependent changes in gene expression in PBMCs in healthy individuals. Genes that may be affected by DE inhalation are involved in inflammatory and oxidative stress processes.

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Peretz A, Peck EC, Bammler TK, Beyer RP, Sullivan JH, Trenga CA, Srinouanprachnah S, Farin FM, Kaufman JD