Cellular senescence markers appear in motor cortex and spinal cord tissue of TDP-43Q331K ALS mice before significant functional decline, establishing senescence as an early pathological event rather than a downstream consequence. Treatment with the senolytic combination dasatinib and quercetin (D&Q) improved motor behavior, preserved layer V cortical neurons, reduced plasma neurofilament light chain (a biomarker of axonal damage), and enhanced motor cortex excitability. Critically, cortical microglia showed reduced TDP-43 protein burden and senescence markers, suggesting these immune cells as a primary cellular mediator of senolytic benefit.
This is a meaningful advance in ALS mechanistic research. The TDP-43 proteinopathy connection is particularly compelling — TDP-43 mislocalization is a defining pathological hallmark in roughly 97% of ALS cases, and demonstrating that senescent microglia accumulate this burden links two major disease mechanisms. D&Q is already in human clinical trials for conditions including pulmonary fibrosis and diabetic kidney disease, giving this mouse finding unusual translational proximity. However, the study is entirely preclinical; ALS mouse models have notoriously poor predictive validity for human trials, and effect sizes in rodent ALS studies frequently fail to replicate. The neurofilament light chain reduction is encouraging as it mirrors a clinically validated biomarker. Longevity-focused readers should note that D&Q senolytics are increasingly studied for multiple aging pathologies — this adds neurodegeneration to that portfolio. An early-phase human ALS senolytic trial would be the logical and urgently needed next step.
