SELENOS and Parkinson disease: For the rest of selenoproteins (Fig 2G), the mRNA level of Seli was decreased by 15%, 21.1%, and 16.3% (p < 0.05) in substantia nigra, cortex, and hippocampus, respectively, and that of Sepp1 was decreased by 15.6% and 16.7% (p < 0.05) in substantia nigra and pons of the PD mice, respectively.