Brain tyrosinase overexpression implicates age-dependent neuromelanin production in Parkinson’s disease pathogenesis

It is unclear if neuromelanin plays a role in Parkinson’s disease pathogenesis since common laboratory animals lack this pigment. Authors show here that overexpression of human tyrosinase in the substantia nigra of rats resulted in an age-dependent production of human-like neuromelanin within nigral dopaminergic neurons and is associated with a Parkinson’s disease phenotype when allowed to accumulate above a specific threshold.