Conserved nicotine-activated neuroprotective pathways involve mitochondrial stress

Summary Tobacco smoking is a risk factor for several human diseases. Conversely, smoking also reduces the prevalence of Parkinson’s disease (PD), whose hallmark is degeneration of substantia nigra dopaminergic neurons (DNs). We use C. elegans as a model to investigate whether tobacco-derived nicotine activates nicotinic acetylcholine receptors (nAChRs) to selectively protect DNs. Using this model, we demonstrate conserved functions of DN-expressed nAChRs. We find that DOP-2, a D3-receptor homolog, MCU-1, a mitochondrial calcium uniporter, PINK-1 (PTEN-induced kinase 1), and PDR-1 (Parkin) are required for nicotine-mediated protection of DNs. Together, our results support involvement of a calcium-modulated, mitochondrial stress-activated PINK1/Parkin-dependent pathway in nicotine-induced neuroprotection. This suggests that nicotine-selective protection of substantia nigra DNs is due to the confluence of two factors: first, their unique vulnerability to mitochondrial stress, which is mitigated by increased mitochondrial quality control due to PINK1 activation; and second, to their specific expression of D3 receptors.