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Updated: Jun 2, 2025
Techniques to Induce and Quantify Cellular Senescence
Published on: May 1, 2017
Comparative evaluation of cellular senescence in naturally aged and stress-induced murine macrophages for identifying
Md Danish1, Bhawna Diwan1, Amit Kumar1
1Faculty of Applied Sciences & Biotechnology, Shoolini University, Solan, 173229, India.
Background:
The role and relevance of macrophages both as causes and therapeutics of cellular senescence is rapidly emerging. However, current knowledge regarding the extent and depth of senescence in macrophages in vivo is limited and controversial. Further, acute models of stress-induced senescence in transformed/cancerous macrophage cell lines are being used although their efficacy and relevance are not characterized.
Methods And Results:
The present study sought to address these aspects by first comparing prevalent senescence in naturally aged murine peritoneal macrophages, and then assessing the effects of two different stressors (LPS and H2O2) in inducing premature senescence in young peritoneal macrophages. Next, RAW264.7 cell line was exposed to respective stressors and their efficiency in recapitulating the effects of natural senescence markers was characterized. We observed strong upregulation of primary markers of senescence such as SA-β-gal activity, p53, p21, p16Inka4a, Rb, ATM, and Lamin B1in naturally aged mice along with increased SASP proteins (IL-6/TNF-α/MCP-1) and redox stress (ROS and NO). Aged macrophages also demonstrated severely reduced phagocytosis. Exposure to both LPS and H2O2 in young macrophages invoked the expression of all primary markers of senescence although SASP protein expression was exaggerated in LPS stimulation. Similarly, ROS and NO expression increased while phagocytosis decreased. Stimulation of RAW264.7 cells generally revealed a similar trend although the depth of all measured parameters was ostensibly stronger in young peritoneal macrophages. Among the two stressors, LPS stimulation appeared to be relatively more potent.
Conclusion:
Overall, this study emphasizes that LPS exposure to young peritoneal macrophages more strongly recapitulates in vivo cellular senescence in macrophages.
Insights
Lipopolysaccharide (LPS) exposure to young macrophages best models natural cellular senescence. This finding is crucial for understanding aging and developing macrophage-based therapies.
Area of Science:
- Immunology
- Cell Biology
- Aging Research
Background:
- Cellular senescence in macrophages is an emerging area with limited in vivo data.
- Current stress-induced senescence models in macrophage cell lines lack characterization.
Purpose of the Study:
- Compare senescence in naturally aged vs. young macrophages.
- Assess LPS and H2O2 effects on inducing premature senescence.
- Evaluate RAW264.7 cell line's relevance for senescence studies.
Main Methods:
- Compared naturally aged murine peritoneal macrophages with young ones.
- Induced premature senescence in young macrophages using LPS and H2O2.
- Analyzed senescence markers, SASP proteins, redox stress, and phagocytosis.
Main Results:
- Naturally aged macrophages showed upregulated senescence markers, increased SASP, redox stress, and reduced phagocytosis.
- LPS and H2O2 induced senescence markers in young macrophages, with LPS exaggerating SASP.
- RAW264.7 cells showed similar trends but less pronounced than primary macrophages.
Conclusions:
- Lipopolysaccharide (LPS) exposure in young peritoneal macrophages is a potent model for in vivo cellular senescence.
- This study provides a more relevant model for investigating macrophage senescence.
