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Single-Cell Fluorescence Imaging Reveals Heterogeneity in Senescence Biomarkers and Identifies Rapamycin-Responsive Sub-Populations

  • 0Monash Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Aging Cell +

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September 3, 2025

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September 3, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

Cellular senescence, a state of irreversible cell cycle arrest, shows biomarker heterogeneity. This study reveals nuclear area as a robust indicator, correlating with IL-6 expression and SASP, and proposes an improved analysis method.

Area Of Science

  • Cell Biology
  • Aging Research
  • Biomarker Discovery

Background

  • Cellular senescence is characterized by cell cycle arrest and the senescence-associated secretory phenotype (SASP).
  • Existing biomarkers like SA-βgal, p21, and p16 have limitations in universally defining senescence and addressing expression heterogeneity.
  • Understanding senescence heterogeneity is crucial for developing targeted therapies.

Purpose Of The Study

  • To investigate cellular heterogeneity in senescence using single-cell fluorescence imaging.
  • To identify robust biomarkers for cellular senescence and their correlation with SASP.
  • To develop an improved method for quantifying senescence markers and evaluate senomorphic agent efficacy.

Main Methods

  • Single-cell fluorescence imaging of human fibroblasts undergoing chemotherapy-induced or oxidative stress-induced senescence.
  • Assessment of multiple markers: SA-βgal activity, p21, IL-6 expression, nuclear area, and cell area.
  • Development of an induction threshold method for biomarker quantification and analysis of rapamycin effects.

Main Results

  • Significant heterogeneity in SA-βgal activity and distinct senescent cell subpopulations were observed.
  • Nuclear and cell area measurements proved to be robust senescence indicators with high variability.
  • Specific nuclear area subpopulations correlated with IL-6 expression, linking biomarker heterogeneity to SASP.
  • Rapamycin selectively targeted specific biomarker-expressing subpopulations in both senescence models.

Conclusions

  • Cellular senescence exhibits significant heterogeneity in biomarker expression, impacting the SASP.
  • Nuclear area is a reliable indicator of senescence, with specific subpopulations linked to IL-6 levels.
  • An induction threshold method enhances senescence biomarker quantification, and rapamycin demonstrates targeted efficacy.