ATM-deficient neural precursors develop senescence phenotype with disturbances in autophagy

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Ataxia-telangiectasia (A-T) is a genetic disorder caused by ATM gene mutations, leading to neurodegeneration and premature aging.
• The brain is significantly affected in A-T, making neural progenitor cells (NPCs) a critical focus for understanding disease mechanisms.
• ATM kinase plays a role in DNA damage response, oxidative stress, and autophagy, processes relevant to neurodegeneration.

Purpose of the Study:

• To investigate the senescence of neural progenitor cells (NPCs) derived from A-T reprogrammed fibroblasts.
• To explore the role of oxidative stress in the observed senescence and autophagy impairment in A-T NPCs.
• To identify potential therapeutic targets for A-T disease.

Main Methods:

• Neural differentiation of induced pluripotent stem cells (iPSCs) from A-T fibroblasts.
• Culturing A-T NPCs under varying oxygen concentrations (5% and 20%) and hydrogen peroxide (H2O2) treatment.
• Assessing senescence markers (SA-β-gal activity, IL-6, IL-8 secretion) and autophagy/mitophagy function (response to chloroquine).

Main Results:

• A-T NPCs exhibited senescence features, including increased SA-β-gal activity and elevated IL-6/IL-8 secretion, under 5% oxygen.
• Elevated oxidative stress was observed in A-T NPCs, correlating with senescence.
• Autophagy and mitophagy were impaired in A-T NPCs, showing no response to chloroquine, and were further exacerbated by increased oxygen or H2O2.
• A-T NPCs showed a response to treatments that control NPCs did not.

Conclusions:

• Oxidative stress is implicated as a key factor driving senescence and autophagy dysfunction in A-T NPCs.
• Senescent A-T cells present a promising avenue for therapeutic intervention in ataxia-telangiectasia.
• Understanding the interplay between oxidative stress, senescence, and autophagy is crucial for A-T treatment strategies.