Female Mice Gain More From Senescent Cell Removal Than Males
Multi-omics study finds female aging mice accumulate more p16⁺ senescent cells and benefit more from their targeted clearance.
Summary
Researchers used transcriptomics, proteomics, and a transgenic mouse model to investigate sex differences in the accumulation and clearance of p16⁺ senescent cells during aging. Female mice accumulated significantly more p16⁺ cells across multiple tissues—especially the liver—compared to males. Using the p16-3MR model, selective elimination of these cells improved grip strength, promoted skin regeneration, and reduced liver damage exclusively in females. Multi-omics profiling showed that clearance shifted female liver molecular profiles toward youthful states, improving mitochondrial function and reducing inflammation. These molecular patterns resembled those produced by calorie restriction, rapamycin, and acarbose. Key genes Srm, Cd36, and Lrrfip1 were identified as part of a conserved mitochondrial-immune regulatory network, suggesting sex must be treated as a critical variable in senolytic therapy development.
Detailed Summary
Cellular senescence—marked by stable cell cycle arrest and expression of p16INK4A—is a recognized driver of tissue aging, inflammation, and age-related disease. While clearing p16⁺ cells has been shown to extend healthspan in mice, whether these benefits differ between sexes has remained poorly understood. This study systematically addressed that gap using integrative omics and functional experiments in both male and female aging mice.
The research team first analyzed a publicly available single-nucleus RNA sequencing (snRNA-seq) dataset covering eight tissues across five age groups in C57BL/6 mice. They found that the proportion of Cdkn2a⁺ cells increased with age in both sexes, but females accumulated p16⁺ cells roughly three times faster between 16 and 23 months compared to males. Four tissues—liver, lung, inguinal white adipose tissue, and gonadal white adipose tissue—showed significantly higher p16⁺ cell burdens in aged females. Bulk RNA-seq data confirmed elevated senescence gene set scores (SenMayo) in aged female livers, validating the snRNA-seq findings. In the female liver, both immune cell expansion and intrinsic upregulation of Cdkn2a contributed to the increased senescent cell burden.
To functionally test the consequences of this sex difference, the team used the p16-3MR transgenic mouse model, which allows selective ablation of p16⁺ cells via ganciclovir (GCV) treatment. At 21–24 months, GCV-treated female mice showed reduced liver p16⁺ cell staining, lower plasma alanine aminotransferase (ALT—a marker of liver damage), improved grip strength, and enhanced skin wound healing. Males showed no significant improvement on any of these measures, establishing a clear female-specific functional benefit from senescent cell clearance.
Multi-omics profiling of liver tissue after p16⁺ cell clearance in females revealed a shift toward more youthful transcriptomic and proteomic profiles. Enriched pathways included mitochondrial biogenesis and oxidative phosphorylation, while inflammatory signaling was suppressed. Strikingly, the molecular signature produced by p16⁺ cell clearance in female livers closely resembled signatures from established longevity interventions—calorie restriction, rapamycin, and acarbose—suggesting shared mechanistic pathways. Integrative analysis with independent datasets identified a conserved transcriptional network anchored by Srm (spermidine synthase), Cd36 (fatty acid translocase), and Lrrfip1 (immune regulator), pointing to mitochondrial-immune crosstalk as a central mechanism.
The study establishes sex as a critical biological variable in senescent cell biology and senolytic responsiveness, with implications for clinical translation of senolytic therapies. Its findings suggest that sex-stratified approaches will be essential for maximizing the efficacy and safety of anti-senescence interventions in aging humans.
Key Findings
- Female aging mice accumulate ~3x more p16⁺ senescent cells than males by 23 months, especially in the liver.
- Selective clearance of p16⁺ cells improved grip strength, skin healing, and liver function exclusively in females.
- Female liver multi-omics after clearance showed improved mitochondrial activity and reduced inflammation resembling longevity interventions.
- Molecular signatures from p16⁺ clearance overlapped with those of calorie restriction, rapamycin, and acarbose.
- Conserved network of Srm, Cd36, and Lrrfip1 identified as shared mitochondrial-immune regulatory hub across interventions.
Methodology
Study used publicly available snRNA-seq (GSE247719, 8 tissues, 5 age groups) and bulk RNA-seq (GSE132040) datasets to map sex-specific p16⁺ cell dynamics. Functional experiments used the p16-3MR transgenic mouse model in 21–24-month-old male and female C57BL/6 mice with ganciclovir-induced p16⁺ cell ablation. Liver tissue was profiled by RNA-seq and proteomics, with results compared to published longevity intervention datasets.
Study Limitations
The mouse model uses p16-driven ablation, which may not fully recapitulate pharmacological senolytics used in humans, and p16⁺ cells are heterogeneous—not all are harmful senescent cells. Sample sizes in the functional experiments were small (N=3–6 per group), limiting statistical power. The study does not address hormonal mechanisms (e.g., estrogen loss post-menopause) that might explain why females accumulate more p16⁺ cells, leaving causal pathways partially unresolved.
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