Epsin 3 Promotes Cellular Senescence Through Reactive Oxygen Species-Mediated Induction of DNA Damage
Yukihiro Ikegaki1, Anju Terachi1, Shunsuke Yamao1
1Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan.
Abstract:
Cellular senescence is caused by various stresses, including DNA damage, oxidative stress, oncogene activation, and telomere shortening. However, the detailed molecular mechanisms of cellular senescence have yet to be elucidated. Recently, using comparative transcriptomics and quantitative PCR, we identified several genes that are specifically upregulated in senescent cells in a p53-dependent manner, including Epsin 3 (EPN3). However, the functional relevance of EPN3 to senescence has not yet been defined. Here, we performed functional analyses to investigate the relationship between EPN3 and the senescence program. We found that EPN3 knockdown suppressed senescent phenotypes induced by DNA damage. Furthermore, ectopic expression of EPN3 induced senescence accompanied by increased reactive oxygen species (ROS) and accumulation of DNA damage. Furthermore, EPN3-induced DNA damage was suppressed by genetic and pharmacological inhibition of Rac1. Finally, treatment with ROS scavengers, N-acetyl-l-cysteine (NAC) and l-Ascorbic Acid (LAA), prevented EPN3-induced DNA damage, and a Rac1 inhibitor reduced ROS levels in EPN3-expressing stable clones. These results indicate that EPN3 induces DNA damage and promotes senescence via Rac1 activity and ROS generation.
Insights
Epsin 3 (EPN3) promotes cellular senescence by inducing DNA damage and reactive oxygen species (ROS) through Rac1 activity. This finding clarifies a key molecular mechanism in the senescence program.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Cellular senescence is a complex process triggered by various stressors, crucial in aging and disease.
- The precise molecular drivers of senescence remain incompletely understood.
- Epsin 3 (EPN3) was identified as a gene upregulated in senescent cells via a p53-dependent pathway.
Purpose of the Study:
- To investigate the functional role of Epsin 3 (EPN3) in the cellular senescence program.
- To elucidate the molecular mechanisms by which EPN3 influences senescence.
Main Methods:
- Comparative transcriptomics and quantitative PCR to identify EPN3.
- Functional analyses including gene knockdown and ectopic expression of EPN3.
- Assessment of senescent phenotypes, reactive oxygen species (ROS) levels, and DNA damage.
- Genetic and pharmacological inhibition of Rac1.
- Treatment with ROS scavengers (NAC, LAA).
Main Results:
- Knockdown of EPN3 attenuated DNA damage-induced senescence.
- Ectopic EPN3 expression triggered senescence, elevated ROS, and caused DNA damage.
- Rac1 inhibition suppressed EPN3-induced DNA damage.
- ROS scavengers prevented EPN3-induced DNA damage, and Rac1 inhibition reduced ROS.
Conclusions:
- EPN3 is a key mediator that induces cellular senescence.
- EPN3 promotes senescence through Rac1 activation and subsequent ROS generation, leading to DNA damage.
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