Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair

In the present study we leverage the power of mass cytometry by time-of-flight (CyTOF) to define, at the single-cell level, mesenchymal bone and marrow senescent cells in mice during fracture. Three main CyTOF experiments were performed:
1) TIMECOURSE: Assessment of senescent cell burden in skeletal and immune cell populations during a 28-day timecourse of fracture healing.
2) P21-ATTAC: Identification of cell populations targeted through p21+ cell clearance in p21-ATTAC mice.
3) OCH-STEM: In-depth assessment of osteochondroprogenitor (OCH) cells through expanded panel, including skeletal stem cell (SSC) markers.

在本研究中，我们借助飞行时间质谱流式细胞术（CyTOF）的强大功能，在单细胞层面上，对小鼠骨折过程中的骨髓和骨骼间充质衰老细胞进行界定。共进行了三项主要的CyTOF实验：
1) 时间进程：评估骨骼和免疫细胞群体在28天骨折愈合时间进程中的衰老细胞负荷。
2) P21-ATTAC：在p21-ATTAC小鼠中，通过p21+细胞清除识别靶向细胞群体。
3) OCH-STEM：通过扩展的检测面板，对骨软骨生发细胞（OCH）进行深入评估，包括骨骼干细胞（SSC）标志物。