Extrinsic Macrophages Protect While Tendon Progenitors Degrade: Insights from a Tissue Engineered Model of Tendon Compartmental Crosstalk
Overview
Biotechnology
Authors
Affiliations
Tendons are among the most mechanically stressed tissues of the body, with a functional core of type-I collagen fibers maintained by embedded stromal fibroblasts known as tenocytes. The intrinsic load-bearing core compartment of tendon is surrounded, nourished, and repaired by the extrinsic peritendon, a synovial-like tissue compartment with access to tendon stem/progenitor cells as well as blood monocytes. In vitro tendon model systems generally lack this important feature of tissue compartmentalization, while in vivo models are cumbersome when isolating multicellular mechanisms. To bridge this gap, an improved in vitro model of explanted tendon core stromal tissue (mouse tail tendon fascicles) surrounded by cell-laden collagen hydrogels that mimic extrinsic tissue compartments is suggested. Using this model, CD146 tendon stem/progenitor cell and CD45 F4/80 bone-marrow derived macrophage activity within a tendon injury-like niche are recapitulated. It is found that extrinsic stromal progenitors recruit to the damaged core, contribute to an overall increase in catabolic ECM gene expression, and accelerate the decrease in mechanical properties. Conversely, it is found that extrinsic bone-marrow derived macrophages in these conditions adopt a proresolution phenotype that mitigates rapid tissue breakdown by outwardly migrated tenocytes and F4/80 "tenophages" from the intrinsic tissue core.
Stauber T, Moschini G, Hussien A, Jaeger P, De Bock K, Snedeker J Elife. 2025; 12.
PMID: 39918402 PMC: 11805502. DOI: 10.7554/eLife.87092.
Human Tendon-on-a-Chip for Modeling the Myofibroblast Microenvironment in Peritendinous Fibrosis.
Ajalik R, Linares I, Alenchery R, Zhang V, Wright T, Miller B Adv Healthc Mater. 2024; 14(4):e2403116.
PMID: 39544139 PMC: 11804843. DOI: 10.1002/adhm.202403116.
The roles and mechanisms of the NF-κB signaling pathway in tendon disorders.
Li H, Li Y, Luo S, Zhang Y, Feng Z, Li S Front Vet Sci. 2024; 11:1382239.
PMID: 38978635 PMC: 11228182. DOI: 10.3389/fvets.2024.1382239.
Human tendon-on-a-chip for modeling vascular inflammatory fibrosis.
Awad H, Ajalik R, Alenchery R, Linares I, Wright T, Miller B Res Sq. 2024; .
PMID: 38168335 PMC: 10760304. DOI: 10.21203/rs.3.rs-3722255/v1.
Bautista C, Srikumar A, Tichy E, Qian G, Jiang X, Qin L Front Physiol. 2023; 14:1122348.
PMID: 36909235 PMC: 9992419. DOI: 10.3389/fphys.2023.1122348.