Title : Detrimental effects of light at 610 nm on dopamine neurons and implications for PD onset
Abstract:
Light pollution has recently become a significant global environmental issue. Interestingly, several in vivo approaches and worldwide correlation studies of Parkinson disease onsets have shown to strongly correlate with the distribution of light pollution. In particular it has been shown that artificial light had profound detrimental effects on dopaminergic neurons. In fact, the prolonged exposure of rats and mice to fluorescent light resulted in increase of neuromelanin granules and damage of dopamine neurons in the substantia nigra. In fact, these findings suggest that light pollution may be a key environmental factor implicated in the preferential degeneration of dopamine neurons in PD. In addition, we have recently shown that electromagnetic wavelengths around 600nm, also emitted by florescent light lamps, reach deep into the mouse, rat, human brains.
This project aims at characterizing light-induced neurodegeneration by using the dopaminergic cell model: MN9D. This cell line was exposed to four wavelengths: 485 nm, 535 nm, 610 nm and 710 nm in order to evaluate the wavelengths at which the fluorescent light was responsible for the detrimental effects observed on the dopaminergic neurons of rats and mice used in our previous studies. In particular we showed that light at 610 nm was the most harmful wavelength for the MN9D and stickily had no effect on control non-dopaminergic cells. Moreover, 610 nm exposure of differentiated MN9D caused a decrease in cell viability and a strong statistically significant increase in ROS production compared to controls, especially when cells were co-treated with an oxidative agent (H2O2). Our results strongly suggest that light potentiates oxidative stress specifically in dopaminergic cells through dopamine oxidation. Moreover, future experiments will be performed using human iPSC-cells from different patients having mutations associated with PD to investigate the relationship between environment such as the prolonged exposure to artificial light and genetic factors.
What will audience learn from your presentation?
• That artificial light had profound detrimental effects on dopaminergic neurons, in vivo.
• That the light wavelength at 610 nm reaches deep inside mouse, rat and human brains.
• That chronic and acute light exposure at 610 nm of the dopaminergic neuronal cell model, MN9D results in increases of ROS production and overall neuronal cytotoxicity.
• In conclusion, the presented data would strongly suggest that chronic artificial light exposure might become a risk factor for Parkinson’s Disease.
