Diesel exhaust particles induce oxidative stress, proinflammatory signaling, and P-glycoprotein up-regulation at the blood-brain barrier

Anika M.S. Hartz, Björn Bauer, Michelle L. Block, Jau Shyong Hong, David S. Miller

Research output: Contribution to journalArticle

154 Scopus citations


Here, we report that diesel exhaust particles (DEPs), a major constituent of urban air pollution, affect blood-brain barrier function at the tissue, cellular, and molecular levels. Isolated rat brain capillaries exposed to DEPs showed increased expression and transport activity of the key drug efflux transporter, P-glycoprotein (6 h EC50 was ∼5 μg/ml). Upregulation of P-glycoprotein was abolished by blocking transcription or protein synthesis. Inhibition of NADPH oxidase or pretreatment of capillaries with radical scavengers ameliorated DEP-induced P-glycoprotein up-regulation, indicating a role for reactive oxygen species in signaling. DEP exposure also increased brain capillary tumor necrosis factor-α (TNF-α) levels. DEP-induced P-glycoprotein up-regulation was abolished when TNF-receptor 1 (TNF-R1) was blocked and was not evident in experiments with capillaries from TNF-R1 knockout mice. Inhibition of JNK, but not NF-κB, blocked DEP-induced P-glycoprotein up-regulation, indicating a role for AP-1 in the signaling pathway. Consistent with this, DEPs increased phosphorylation of c-jun. Together, our results show for the first time that a component of air pollution, DEPs, alters blood-brain barrier function through oxidative stress and proinflammatory cytokine production. These experiments disclose a novel blood-brain barrier signaling pathway, with clear implications for environmental toxicology, CNS pathology, and the pharmacotherapy of CNS disorders.

Original languageEnglish (US)
Pages (from-to)2723-2733
Number of pages11
JournalFASEB Journal
Issue number8
StatePublished - Aug 1 2008



  • JNK
  • NADPH oxidase
  • Reactive oxygen species
  • TNF-α, TNF-receptor 1

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

Cite this