Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2022 May 2;42(1):14.
doi: 10.1186/s41232-022-00202-0.

The superficial zone of articular cartilage

Taku Saito  1
Affiliations
Review

The superficial zone of articular cartilage

Taku Saito. Inflamm Regen. .

Abstract

The superficial zone of articular cartilage contributes to smooth joint motion through the production of proteoglycan 4 (PRG4), also known as lubricin. Recent studies indicate novel effects of PRG4 as a signaling molecule, other than a simple extracellular matrix protein. Additionally, the accumulating evidence displays that various molecules and signaling pathways are involved in regulating the superficial zone and PRG4 expression. In addition, Prg4-expressing cells include a progenitor population of articular chondrocytes. Several non-clinical and clinical studies have shown that PRG4 and related molecules are promising candidates for disease-modifying drugs for treating osteoarthritis. Since PRG4 is also expressed in the synovium, tendons, and ligaments, further studies of PRG4-related pathways and PRG4-positive cells may elucidate the mechanisms underlying joint homeostasis.

Keywords: Articular cartilage; Lubricin; Osteoarthritis; Superficial zone.

PubMed Disclaimer

Conflict of interest statement

The author declares no competing interests.

Figures

Fig. 1
Fig. 1
Schematic diagram representing the molecular pathway in which PRG4 suppresses the differentiation of SFZ cells, osteophyte formation, and ectopic ossification
Fig. 2
Fig. 2
Schematic diagram representing the molecular pathways that regulate PRG4 expression
See this image and copyright information in PMC

References

    1. Bannuru RR, Osani MC, Vaysbrot EE, Arden NK, Bennell K, Bierma-Zeinstra SMA, Kraus VB, Lohmander LS, Abbott JH, Bhandari M, Blanco FJ, Espinosa R, Haugen IK, Lin J, Mandl LA, Moilanen E, Nakamura N, Snyder-Mackler L, Trojian T, Underwood M, McAlindon TE. OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage. 2019;27(11):1578–1589. doi: 10.1016/j.joca.2019.06.011. - DOI - PubMed
    1. Lane JM, Weiss C. Review of articular cartilage collagen research. Arthritis Rheum. 1975;18(6):553–562. doi: 10.1002/art.1780180605. - DOI - PubMed
    1. Eschweiler J, Horn N, Rath B, Betsch M, Baroncini A, Tingart M, Migliorini F. The biomechanics of cartilage-an overview. Life (Basel) 2021;11(4):302. doi: 10.3390/life11040302. - DOI - PMC - PubMed
    1. Poole AR. An introduction to the pathophysiology of osteoarthritis. Front Biosci. 1999;4(1-3):D662–D670. doi: 10.2741/Poole. - DOI - PubMed
    1. Marcelino J, Carpten JD, Suwairi WM, Gutierrez OM, Schwartz S, Robbins C, Sood R, Makalowska I, Baxevanis A, Johnstone B, Laxer RM, Zemel L, Kim CA, Herd JK, Ihle J, Williams C, Johnson M, Raman V, Alonso LG, Brunoni D, Gerstein A, Papadopoulos N, Bahabri SA, Trent JM, Warman ML. CACP, encoding a secreted proteoglycan, is mutated in camptodactyly-arthropathy-coxa vara-pericarditis syndrome. Nat Genet. 1999;23(3):319–322. doi: 10.1038/15496. - DOI - PubMed

LinkOut - more resources