Senolytic Strategies Rejuvenate Microglia in the White Matter of Aged Mice
A study in naturally aged mice found that pharmacological and pharmacogenetic senotherapeutic approaches reduced a senescent, disease-associated microglial population in a region of brain white matter. The interventions were linked with a more youthful microglial organization, but the findings remain preclinical and do not establish a benefit in humans.
Researchers have identified a senescent, inflammatory population of microglia concentrated in the brain white matter of naturally aged mice—and found that several senotherapeutic approaches partially reduced it.
The study focused on the fimbria, a white-matter structure adjacent to the hippocampus. White matter undergoes structural and functional changes associated with cognitive decline in later life, but the cellular basis of its vulnerability remains incompletely understood.
Using regional gene-expression profiling, immunolabeling, digital spatial profiling and spatial molecular imaging, the researchers characterized a microglial population found specifically in the aged brain. These cells displayed features of both disease-associated microglia, or DAM, and a senescence-related “SenBrain” gene signature. The population also expressed galectin-3, identified in the study through the gene and protein markers GAL3 and Lgals3.
Microglia are innate immune cells located in the brain. According to the study, the aged white-matter population had a proinflammatory profile and appeared to arise through multiple possible cell-state transitions, based on single-cell spatial trajectory analyses. That analysis suggests how the population may develop, but it does not establish a single causal pathway.
The researchers then used pharmacogenetic and pharmacological senotherapeutic interventions in aged mice. Both approaches reduced the abundance of GAL3-positive, disease-associated microglia in the fimbria and restored a microglial arrangement described as more youthful. The findings indicate that this senescence- and DAM-enriched state was at least partly reversible in the mouse brain.
The work adds to research examining how senescent cells may contribute to age-related changes in brain function and neurodegeneration. However, the evidence described here comes from aged mice rather than a human clinical trial. The study therefore does not show that senolytic or related treatments remove senescent microglia in people, improve human cognition, or treat a neurodegenerative condition.
The source also notes that relatively little clinical testing has assessed established, low-cost senolytic drugs in patients with neurodegenerative diseases, citing one small Alzheimer’s disease trial. The new findings identify a potential cellular target in aging brain white matter, while leaving its relevance to human disease and treatment unresolved.
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