Neurotoxicity assessment of triazole fungicides on mitochondrial oxidative respiration and lipids in differentiated human SH-SY5Y neuroblastoma cells

• Published in: Neurotoxicology (Park Forest South) 2020-09, Vol.80, p.76-86
• Main Authors: Sanchez, Christina L., Souders, Christopher L., Pena-Delgado, Carlos J., Nguyen, Khaai T., Kroyter, Noa, Ahmadie, Nader El, Aristizabal-Henao, Juan J., Bowden, John A., Martyniuk, Christopher J.
• Format: Article
• Language: English
• Subjects: Abundance; Agrochemicals; Antifungal agents; Biocompatibility; Bioenergetics; Cell differentiation; Cell viability; Electron transport; Environmental chemicals; Exposure; Fatty acids; Fungi; Fungicides; Lecithin; Lipidomics; Lipids; Membrane potential; Membranes; Mitochondria; Movement disorders; Neuroblastoma; Neuroblasts; Neurodegeneration; Neurodegenerative diseases; Neuroprotection; Neurotoxicity; Occupational exposure; Occupational health; Oligomycin; Parkinson's disease; Pesticides; Phosphatidylcholine; Phosphatidylethanolamine; Propiconazole; Reactive oxygen species; Respiration; Tebuconazole; Toxicity; Triazoles; Triglycerides
• ISSN: 0161-813X; 1872-9711
• DOI: 10.1016/j.neuro.2020.06.009

•Triazole fungicides propiconazole and tebuconazole affect mitochondrial membrane potential in SHSY-5Y cells.•Propiconazole affects mitochondrial bioenergetics by decreasing basal respiration.•Some ceramides and fatty acids are associated with mitochondrial dysfunction and neurotoxicity.•Propiconazole is more neurotoxic to SH-SY5Y cells than tebuconazole based on the endpoints measured.•This study provides insight into pesticide toxicity and Parkinson’s disease using lipidomics. Indiscriminate overuse or occupational exposure to agricultural chemicals can lead to neurotoxicity. Many pesticides act to impair mitochondrial function which can lead to exacerbation of neurodegeneration. Triazole fungicides are applied to grain, fruit, and vegetable crops to combat mold and fungi and their use is increasing worldwide. Here, we assessed the in vitro toxicity of two widely used triazole fungicides, propiconazole and tebuconazole, to mitochondria using differentiated SH-SY5Y neuroblastoma cells as an in vitro cell model used in Parkinson’s disease research. Cell viability (based on ATP levels), mitochondrial membrane potential, oxidative respiration, and reactive oxygen species (ROS) were measured following fungicide treatments. Cell viability was decreased with 100 μM propiconazole after 24 and 48 h, while tebuconazole required higher doses to affect viability (−200 μM at 24 h). Mitochondrial membrane potential (MMP) was reduced with 50 μM propiconazole after 24 h while 200 μM tebuconazole reduced MMP. Oxidative respiration of SH-SY5Y cells was then measured using a XFe24 Flux analyzer and 100 μM propiconazole reduced basal respiration, oligomycin-induced ATP production, and FCCP-induced maximum respiration by −40−50%, while tebuconazole did not affect mitochondrial bioenergetics at the concentrations tested. Acute exposure to 100 μM propiconazole over 4 h did not immediately affect oxidative respiration in SH-SY5Y cells. ROS were not induced by propiconazole and tebuconazole up to 100 and 300 μM respectively. Based on these results, we focused our lipidomics investigations on SH-SY5Y exposed only to propiconazole, as lipid dysregulation is associated with mitochondrial dysfunction. Both 50 and 100 μM propiconazole altered the abundance of some ceramides, specifically reducing glucosylceramide non-hydroxyfatty acid-sphingosine (HexCer-NS) and increasing N-stearoyl-phytosphingosine (CerNP). Moreover, a recently discovered bioactive lipid called fatty acid ester of