Generation of a p21 Reporter Mouse and Its Use to Identify and Eliminate p21high Cells In Vivo

Abstract

P21 and p16 have been identified as inducers of senescence. Many transgenic mouse models have been developed to target cells expressing high levels of p16Ink4a (p16high) and investigate their potential contribution to tissue dysfunction in aging, obesity, and other pathological conditions. However, the specific roles of p21 in various senescence-driven processes remain unclear. To gain a deeper understanding of p21, we built a p21-3MR mouse model containing a p21 promoter-driven module that allowed us to target cells with high p21Chip expression (p21high). Using this transgenic mouse, we monitored, imaged, and eliminated p21high cells in vivo. We also applied this system to chemically induced weakness and found that the clearance of p21high cells improved doxorubicin (DOXO)-induced multi-organ toxicity in mice. By recognizing p21 transcriptional activation spatially and temporally, the p21-3MR mouse model can be a valuable and powerful tool for studying p21high cells to further understand senescence biology.

Subcellular structure, heterogeneity, and plasticity of senescent cells

“…Furthermore, the varied nature of the senescent process and the inherent complexity of living organisms pose additional challenges. Therefore, transgenic mice expressing fluorescent reporters under the control of p16 (Demaria et al., 2014 ; Liu et al., 2019 ; Ogrodnik, 2021 ) or p21 promoters (Wang et al., 2021 ; Yi et al., 2023 ) added to other animal models like Drosophila melanogaster (Chen et al., 2014 ), Caenorhabditis elegans (Ezcurra et al., 2018 ; Lohr et al., 2019 ), or Zebrafish ( Danio rerio ) (Kishi et al., 2008 ; Morsli et al., 2023 ) may contribute significantly to generate in vivo evidence. Likewise, techniques and protocols for detecting and assessing senescence in preserved or live tissue are underway, including the isolation of SnCs, ex vivo analyses, new probes allowing in vivo imaging, supravital microscopy, and in vivo cell tracking (Biran et al., 2017 ; Rabinowitz & Cui, 2023 ).…”