Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2023

The link between air pollution and neurotoxicity using killifish, X-ray fluorescent microscopy and single cell transcriptomics (#38)

Farzana Kastury 1 , Prabesh Bhattarai 2 , Nelson Nastasia 2 , DeSantis Kathryn 3 , Cosacak I Mehmet 4 , Nicholas Sarah 5 , Hu Chi-Kuo 6 , Caghan Kizil 7 , Bostick Benjamin 8 , Pearson L Brandon 3
  1. Future Industries Institute / STEM, University of South Australia, Mawson Lakes, SA, Australia
  2. Department of Neurology, Columbia University, New York, NY, USA
  3. Mailman School of Public Health, Columbia University, New York, NY, USA
  4. German Center for Neurodegenerative Diseases , Göttingen, Germany
  5. NSLS-II, Brookhaven National Laboratory, Upton, NY, USA
  6. Stonybrook University, Chi-Kuo Hu, Stonybrook , NY, USA
  7. Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
  8. Lamont Doherty Earth Observatory, Columbia University; , Columbia University, New York, NY, USA

Iron (Fe) dis-homeostasis in brain is associated with neurodegenerative diseases; Fe2+ and Fe2+/Fe3+ being more toxic than Fe3+. However, whether exposure to Fe-rich particulate matter (PM) causes Fe to cross the blood-brain barrier, and its impact on neurotoxicity is poorly understood. This study uses African turquoise killifish (Nothobranchius furzeri), an emerging model organism for aging, to assess gene expression in brain cells as a function of age. Steel manufacturing impacted PM (<74 µm) was obtained from Taranto (Southern Italy), a region with significant associations between dust exposure and negative neurobehavioral effect in children. Young (3-months-old) and old (6-months-old) killifish were exposed to either 200 mg PM/L or system water for 72 hours. To detect Fe particles in the brain, fish were euthanized and the brains were cryo-sectioned and dehydrated. We detected Fe hotspots and their speciation at the X-ray Fluorescence Microscopy beamline, National Synchrotron Light Source II. To determine the effects of particle exposure on brain cell types, single cell transcriptomics was performed in the fish telencephalon (forebrain) for both treatments and ages. After 10X sequencing, mapping to killifish genome assembly and clustering analyses, gene expression in all major brain cell types were investigated for changes in treatment-dependent alteration of molecular pathways.  

Significantly higher Fe hotspots in telencephalons of exposed killifish were observed compared to unexposed fish, confirming that Fe-rich particles from the PM sample crossed the blood brain barrier and accumulated in brain. Speciation analysis confirmed the presence of Fe2+/Fe3+ and Fe3+ in brain tissues.

Differential gene expression revealed age-related effects of particle toxicity on various brain cell types. In older killifish, neurodegenerative and immune responses were more pronounced, whereas in young animals the detoxification and neurogenic pathways were enriched. Our results provide the first single cell transcriptomics on killifish brains with particle toxicity in relation to aging.