Neuronal aging leads to disrupted RNA metabolism

ABSTRACT: Aging is one of the most prominent risk factors for neurodegeneration, yet the molecular mechanisms underlying the deterioration of old neurons are mostly unknown. To efficiently study neurodegeneration in the context of aging, we transdifferentiated primary human fibroblasts from aged (i.e. >50 year-old) healthy donors directly into neurons, which retained their aging-associated phenotypes including senescence and dysregulation of CpG methylation. Here we show that aged neurons are broadly depleted of RNA-binding proteins, especially 26 spliceosome components. Intriguingly, splicing proteins – like the dementia and ALS-associated protein TDP-43 – mislocalize to the cytoplasm in aged neurons, which leads to widespread alternative splicing. Although spliceosome components can be sequestered within cytoplasmic stress granules, we find that aged neurons suffer from chronic stress that leads to the segregation of stress granule and spliceosome RNA-binding proteins. We link chronic stress to the accumulation of misfolded proteins and to poor HSP90α chaperone activity. Importantly, we also show that aged neurons respond poorly to acute stress treatments, leading to long-term retention of stress granules and failure to initiate transcription of stress-related heat shock proteins. Together our data demonstrates that dysregulation of RNA metabolism is a key driver of poor resiliency in aged neurons.

INSTRUMENT(S): timsTOF Pro 2

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Xuezhen Ge  

LAB HEAD: Eric Bennett

PROVIDER: PXD055825 | Pride | 2025-02-19

REPOSITORIES: Pride