Urban air particulate matter induces mitochondrial dysfunction in human olfactory mucosal cells

Part Fibre Toxicol. 2020 Jun 1;17(1):18. doi: 10.1186/s12989-020-00352-4.


Background: The adverse effects of air pollutants including particulate matter (PM) on the central nervous system is increasingly reported by epidemiological, animal and post-mortem studies in the last decade. Oxidative stress and inflammation are key consequences of exposure to PM although little is known of the exact mechanism. The association of PM exposure with deteriorating brain health is speculated to be driven by PM entry via the olfactory system. How air pollutants affect this key entry site remains elusive. In this study, we investigated effects of urban size-segregated PM on a novel cellular model: primary human olfactory mucosal (hOM) cells.

Results: Metabolic activity was reduced following 24-h exposure to PM without evident signs of toxicity. Results from cytometric bead array suggested a mild inflammatory response to PM exposure. We observed increased oxidative stress and caspase-3/7 activity as well as perturbed mitochondrial membrane potential in PM-exposed cells. Mitochondrial dysfunction was further verified by a decrease in mitochondria-dependent respiration. Transient suppression of the mitochondria-targeted gene, neuronal pentraxin 1 (NPTX1), was carried out, after being identified to be up-regulated in PM2.5-1 treated cells via RNA sequencing. Suppression of NPTX1 in cells exposed to PM did not restore mitochondrial defects resulting from PM exposure. In contrast, PM-induced adverse effects were magnified in the absence of NPTX1, indicating a critical role of this protein in protection against PM effects in hOM cells.

Conclusion: Key mitochondrial functions were perturbed by urban PM exposure in a physiologically relevant cellular model via a mechanism involving NPTX1. In addition, inflammatory response and early signs of apoptosis accompanied mitochondrial dysfunction during exposure to PM. Findings from this study contribute to increased understanding of harmful PM effects on human health and may provide information to support mitigation strategies targeted at air pollution.

Keywords: Air pollution; Inflammation; Mitochondria; NPTX1; olfactory system; oxidative stress; particulate matter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Air Pollutants / toxicity*
  • Animals
  • Apoptosis / drug effects
  • C-Reactive Protein / genetics
  • C-Reactive Protein / metabolism
  • Cell Culture Techniques
  • Cells, Cultured
  • Cities
  • Cytokines / metabolism
  • Humans
  • Inflammation
  • Male
  • Membrane Potential, Mitochondrial / drug effects
  • Middle Aged
  • Mitochondria / drug effects*
  • Mitochondria / immunology
  • Mitochondria / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Olfactory Mucosa / drug effects*
  • Olfactory Mucosa / metabolism
  • Olfactory Mucosa / pathology
  • Oxidative Stress / drug effects*
  • Particle Size
  • Particulate Matter / toxicity*
  • Transcriptome / drug effects
  • Urbanization


  • Air Pollutants
  • Cytokines
  • Nerve Tissue Proteins
  • Particulate Matter
  • neuronal pentraxin
  • C-Reactive Protein