Introduction::Although motor neuron inclusions that contain hyperphosphorylated TDP-
43 protein (p-TDP-43) are considered an important clue in the pathophysiology of ALS, the main
determinants of the neuronal dysfunction remain unknown.
Method::The spinal cords and motor cortex of 17 people (n=60 tissues) who died of ALS, with 10
controls were tested for p-TDP-43/neurofibrillary tangles (NFTs), biomarkers of neuroinflammation
(GFAP, TMEM 119, miR-155, IL6, TNFα, IL1β, NF-κβ), neurodegeneration (NeuN, myelin basic
protein) and BCL2 family proteins (BCL2, BCLW, BCLXL, and MCL1 each pro-survival as well as
BIM, PUMA, NOXA, BAK, BAX each anti-survival) using in situ based methods including immunohistochemistry.
Results::p-TDP-43 detection was strongly correlated with neuroinflammation and neurodegeneration
in both humans and in a mouse model of ALS with the mutant human TDP-43 gene (B6.Cg-
Tg(Prnp-TARDBP*A315T)95Balo/J). The expression of each BCL2 family protein was significantly
increased compared to the controls and co-localized with p-TDP-43 in both human and mouse
models.
Discussion::To test whether altering BCL2 activity affects ALS pathophysiology, the FDAapproved
drug venetoclax, which blocks BCL2, was started at age 3 mo IP in these mice and prevented
clinical motor neuron dysfunction (n=5), whereas the untreated littermates (n=4) each died of
end-stage paralysis at 5-7 mo. Blocking Bcl2 in the ALS mice reduced neurodegeneration 5-fold
and neuroinflammation by 81%.
Conclusion::It is concluded that: 1) dysregulation of BCL2 family proteins is implicated in ALS,
and 2) blocking Bcl2 alone in the mouse ALS model can markedly reduce the neurodegeneration.