Environmental Exposure Induced Metabolic Profiling Alterations in a Migration Panel between Los Angeles and Beijing

Abstract

Migration provides individuals experiencing different environmental exposure episodes naturally, which offers a chance to attribute physiological response to certain exposure factors. To reveal the mechanism of health effect under environmental exposure, we designed a migration panel study between Los Angeles and Beijing, two cities with different exposure levels. Specifically, serum samples were collected from 27 summer school exchange students three times in total, one week before their departure (LA1), and at least four weeks respectively after their arrival to Beijing (BJ) and return to Los Angeles (LA2). The metabolic profiling was obtained through untargeted metabolomics approach with a high resolution TOF-MS. Combining with a series of statistical methods like Mann-Whitney test and Orthogonal partial least squares discriminant analysis, we screened prospective markers that changed significantly between LA and BJ. The significant decrease (p<0.001, FC>1.2) of indole and its precursor tryptophan in BJ reflected the induction of AhR and CYP by higher levels of pollutants. The decreased cortisol (p<0.001, FC>1.5) was potentially due to the accelerated consumption of CYP3A, supplying further evidence of enhanced CYP activity and related xenobiotics elimination in BJ. On the other hand, the increase of IL-8 and IL-10 from cytokine analysis suggested the oxidative stress during the process. A slightly higher level of uric acid (p<0.01, FC>1.1) along with its precursors implied the upregulation of antioxidation under the environmental exposure in BJ. Generally, this study illustrated that metabolomics offered an effective tool to assess the overall health impact under subchronic exposure.