Identifying the origin and niche environment of nucleus pulposus progenitor cells of the intervertebral disc and its therapeutic applications

尽管有许多关于在各种肌肉骨骼组织中鉴定内源性干/祖细胞群的报道，但在NP组织中没有明确的细胞群报道。此外，调节NP干细胞/祖细胞自我更新和维持的来源或生态位也未知。当前研究的主要目标是鉴定一组特异性标记，以从NP中分离出具有普遍干细胞特征的细胞群。然后，我们试图确定NP组织中干细胞生态位的存在以及NP干细胞在人类IVD衰老和退化中的作用。结果表明，小鼠和人髓核细胞在体外具有克隆性、自我更新和多能分化能力以及体内组织维持能力等干细胞特征。

Despite many reports on the identification of endogenous stem/progenitor cell populations in various musculoskeletal tissues, no definitive cell population has been reported in NP tissue. Furthermore, the origin or niche that regulates the self-renewal and maintenance of NP stem/progenitor cells is also unknown. The primary goal of the current study was to identify a set of specific markers to isolate the cell population sharing universal stem cell characteristics from the NP. Then we sought to determine the presence of a stem-cell niche in NP tissue and the role of NP stem cells in ageing and degeneration of the IVD in humans. Results demonstrated that in mouse and human nucleus pulposus cell populations, isolated by defined surface markers possess stem cell characteristics, such as clonogenicity, self-renewal and multi-potent differentiation ability in vitro, and tissue maintenance ability in vivo.