Notably, a previous investigation of the M83 PD model demonstrates a decrease in tight junction proteins, increased BBB permeability, and astrocytic activation in 8-month-old PD mice, coinciding with the accumulation of oligomeric α-Syn, whereas only a minor decline in occludin is observed in younger PD mice at 4 months of age28. The gene discussed is OCLN; the disease is Parkinson disease.