You are here

| Adult Stem Cells

New Study Identifies the Cell Types Required for Spinal Cord Development

Review of “Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair” from STEM CELLS Translational Medicine by Stuart P. Atkinson

A range of studies supports the identity of type II collagen-expressing cells as early mesenchymal progenitors that become chondrocytes, osteoblasts, stromal cells, and adipocytes in the long bones [1-3]. Following encouraging recent studies by Tong et al. [4] and Wei et al. [5], researchers led by Shuying Yang (University of Pennsylvania, Philadelphia, PA, USA) sought to explore the contribution of type II collagen-expressing progenitors to spinal development and intervertebral disc repair and decipher any aging-related alterations to any such processes in the hope of understanding more regarding the basic mechanisms of spinal development.

Reporting in STEM CELLS Translational Medicine, Li et al. now provide evidence for the significant contribution of type II collagen-expressing progenitors to mouse spinal development and their vital role in intervertebral disc repair and regeneration [6].

The authors used engineered model mice to show that the loss of type II collagen-expressing progenitors during embryonic stages prompted animal death. They also found that the lack of these cells inhibited the formation of the spinal cord and intervertebral discs while reserving the surrounding soft tissues, suggesting their requirement for spinal development. The deletion of type II collagen-expressing progenitors in post-natal mice prompted delayed development; however, these mice also displayed apparent spinal aberrations with a significant impact observed in components of the intervertebral discs.

Subsequent lineage tracing of type II collagen-expressing progenitors in reporter mice revealed that most cells within the spine express type II collagen and that mice exhibited a loss in type II collagen-expressing progenitor number and differentiation ability with increased age.

Finally, fate-mapping studies established the requirement of type II collagen-expressing progenitors in intervertebral disc repair and regeneration in injured three-week-old mice, with a large population of type II collagen-expressing progenitors detected at the injured site at four weeks after injury. Type II collagen-expressing progenitors isolated from the injured site possess tri-lineage differentiation potential and clonogenicity, thereby confirming their progenitor-like fate.

Overall, these findings provide fresh insight into the cell types involved in the development of the spine and the intervertebral discs while also permitting a platform for the development of novel cell therapies for intervertebral disc repair and regeneration.

For more on type II collagen-expressing progenitor cells and novel spine/intervertebral disc repair and regeneration strategies, stay tuned to the Stem Cells Portal!


References

  1. Ono N, Ono W, Nagasawa T, et al., A subset of chondrogenic cells provides early mesenchymal progenitors in growing bones. Nature Cell Biology 2014;16:1157-67.
  2. Serowoky MA, Arata CE, Crump JG, et al., Skeletal stem cells: insights into maintaining and regenerating the skeleton. Development 2020;147.
  3. Matsushita Y, Ono W, and Ono N, Skeletal Stem Cells for Bone Development and Repair: Diversity Matters. Current Osteoporosis Reports 2020;18:189-198.
  4. Tong W, Lu Z, Qin L, et al., Cell therapy for the degenerating intervertebral disc. Translational Research 2017;181:49-58.
  5. Wei Y, Tower RJ, Tian Z, et al., Spatial distribution of type II collagen gene expression in the mouse intervertebral disc. JOR Spine 2019;2:e1070.
  6. Li X, Yang S, Qin L, et al., Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair. STEM CELLS Translational Medicine 2021;10:1419-1432.