Air Pollution and Microglia

Air Pollution Impacts CNS Health

Air Pollution Impacts Brain Health 1Increasing reports implicate outdoor air pollution in  deleterious human health effects (cardiovascular, lung, and the CNS), but the mechanisms through which air pollution may impact the brain are largely unknown (Block and Calderón-Garcidueñas, 2009, Trends in Neurosciences).

Recent Work from The Lab

Work from the Block Lab focuses on how air pollution regulates microglia to impact neuropathology and has shown that:

  1. Diesel exhaust (DE, a significant component of urban pollution and a serious human health concern) activates microglia, as measured by upregulation of the IBA1 marker and a shift to an activated morphology in vivo in rat models (Levesque et al., 2011, EHP).
  2. Neuroinflammation in response to DE exposure in vivo is greatest in brain regions with the highest expression of microglia markers (Levesque et al., 2011, EHP).
  3. Low concentrations of DE particles (DEP, 5μg/ml) in vitro amplify the microglial response to lipopolysaccharide (LPS), suggesting that DE may prime microglia to be more sensitive to additional pro-inflammatory stimuli (Levesque et al., 2011, EHP).
  4. Subchronic (6 month) exposure to DE still causes neuroinflammation in rats and elevates α synuclein, Tau [pS199], and Aβ42, all of which are potential early markers of neurodegenerative diseases (Levesque at al., 2011, Journal of Neuroinflammation).
  5. The adsorbed chemicals and the carbon core of DEP are both capable of activating microglia (Levesque et al., 2013, Journal of Neurochemistry).
  6. DEP neurotoxicity and the production of superoxide is mediated through microgial NOX2 activation and the MAC1 receptor (Levesque et al., 2013, Journal of Neurochemistry)

Together, this recent work supports that DE may be a common, chronic source of microglial activation in the environment that impinges on neurodegenerative disease pathways.

Ongoing Research in the Lab

Our present research strives to define a “Lung-Brain Axis”, which we believe may serve as a common mechanism through which diverse inhaled environmental toxicants (especially urban air pollution) may signal microglial activation upon lung damage to impact CNS disease.

The Lung-Brain Connection