DNA Damage Regulates Senescence-Associated Extracellular Vesicle Release via the Ceramide Pathway to Prevent...

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• DNA damage is a key trigger for cellular senescence, a tumor suppressor mechanism.
• Senescent cells exhibit a senescence-associated secretory phenotype (SASP) and increased extracellular vesicle (EV) release.
• The molecular mechanisms driving increased EV release in senescence are not fully understood.

Purpose of the Study:

• To elucidate the molecular mechanism by which DNA damage induces extracellular vesicle (EV) release in senescent cells.
• To investigate the role of the ceramide synthetic pathway in senescence-associated EV (SA-EV) biogenesis.

Main Methods:

• Analysis of sphingomyelin synthase 2 (SMS2) and neutral sphingomyelinase 2 (nSMase2) expression following DNA damage.
• Measurement of SA-EV biogenesis and release.
• Investigation of the interplay between EV biogenesis, autophagy, and apoptosis.

Main Results:

• DNA damage downregulates SMS2 and upregulates nSMase2, activating the ceramide synthetic pathway.
• Activation of the ceramide pathway promotes SA-EV biogenesis.
• The SA-EV pathway, alongside autophagy, contributes to blocking apoptosis by clearing cytoplasmic DNA fragments.

Conclusions:

• DNA damage-induced activation of the ceramide pathway is a key driver of SA-EV release.
• SA-EVs play a role in cellular homeostasis and protecting senescent cells from excessive inflammation.
• This pathway offers a novel mechanism for managing cellular stress responses.