In rats, TNF-α, IFN-γ, and TGF-β reduce the expression of tight junction proteins such as occludin, claudin, and ZO-1.73 TNF-α, IFN-γ, and TGF-β are increased in ALS, encouraging BCNSB alterations.74,75 Concurrent with inflammation, another hypothesized contributor to ALS pathology is TDP-43 accumulation. Here, TGFB1 is linked to amyotrophic lateral sclerosis.