While several new questions have been raised by this study, we believe that it sheds light on the long-standing question of the origin and regulation of LLCPs, laying the groundwork for future approaches to generate cartilage reparative cells in vivo. Thx for reading till here!

We further show that some reparative Gli1+ cells originate from Pdgfra+ cells outside the cartilage, revealing the surrounding tissues as an unexpected CP source.

Here, we show that Gli1+ cells are the fetal precursors of postnatal LLCPs, and that Gli1+ LLCP precursors remain mostly dormant until postnatal stages. However, in response to genetically-induced cell-cycle arrest targeted to the fetal cartilage, they expand in the cartilage, enabling normal growth

Long bones in the limbs grow via a cartilage template (growth plate), that is progressively replaced by bone. Murine cartilage progenitors (CPs) show a postnatal switch of behaviour, from being short-lived to being self-renewing and long-lived (LLCPs).