Telomerase expression marks transitional growth ‐associated skeletal progenitor/stem cells

In long bones, osteochondral progenitor cells function during rapid bone growth while osteoadipogenic progenitors act during bone maintenance. We showed that mTert is expressed in an age ‐dependent manner and marks growth‐associated osteochondral progenitor cells during transitional growth, a discrete time period between rapid bone growth and bone maintenance. AbstractSkeletal progenitor/stem cells (SSCs) play a critical role in postnatal bone growth and maintenance. Telomerase (Tert) activity prevents cellular senescence and is required for maintenance of stem cells in self ‐renewing tissues. Here we investigated the role ofmTert‐expressing cells in postnatal mouse long bone and found thatmTert expression is enriched at the time of adolescent bone growth.mTert‐GFP+ cells were identified in regions known to house SSCs, including the metaphyseal stroma, growth plate, and the bone marrow. We also show thatmTert‐expressing cells are a distinct SSC population with enriched colony‐forming capacity and contribute to multiple mesenchymal lineages, in vitro. In contrast, in vivo lineage‐tracing studies identifiedmTert+ cells as osteochondral progenitors and contribute to the bone ‐forming cell pool during endochondral bone growth with a subset persisting into adulthood. Taken together, our results show thatmTert expression is temporally regulated and marks SSCs during a discrete phase of transitional growth between rapid bone growth and maintenance.
Source: Stem Cells - Category: Stem Cells Authors: Tags: TISSUE ‐SPECIFIC STEM CELLS Source Type: research