title: Spatiotemporal analysis of putative notochordal cell markers reveals CD24 and keratins 8, 18, and 19 as notochord-specific markers during early human intervertebral disc development.
abstract: In humans, the nucleus pulposus (NP) is composed of large vacuolated notochordal cells in the fetus but, soon after birth, becomes populated by smaller, chondrocyte-like cells. Although animal studies indicate that notochord-derived cells persist in the adult NP, the ontogeny of the adult human NP cell population is still unclear. As such, identification of unique notochordal markers is required. This study was conducted to determine the spatiotemporal expression of putative human notochordal markers to aid in the elucidation of the ontogeny of adult human NP cells. Human embryos and fetuses (3.5-18 weeks post-conception (WPC)) were microdissected to isolate the spine anlagens (notochord and somites/sclerotome). Morphology of the developing IVD was assessed using hematoxylin and eosin. Expression of keratin (KRT) 8, KRT18, KRT19, CD24, GAL3, CD55, BASP1, CTGF, T, CD90, Tie2, and E-cadherin was assessed using immunohistochemistry. KRT8, KRT18, KRT19 were uniquely expressed by notochordal cells at all spine levels at all stages studied; CD24 was expressed at all stages except 3.5 WPC. While GAL3, CD55, BASP1, CTGF, and T were expressed by notochordal cells at specific stages, they were also co-expressed by sclerotomal cells. CD90, Tie2, and E-cadherin expression was not detectable in developing human spine cells at any stage. This study has identified, for the first time, the consistent expression of KRT8, KRT18, KRT19, and CD24 as human notochord-specific markers during early IVD development. Thus, we propose that these markers can be used to help ascertain the ontogeny of adult human NP cells. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. J Orthop Res 34:1327-1340, 2016.
authors.affiliation: Centre For Tissue Injury and Repair, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, United Kingdom.|Department of Orthopaedics, Centro Hospitalar do Porto-Hospital de Santo António, Largo Prof. Abel Salazar, Porto, 4099-001, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rodrigues-Pinto
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, AV Hill Building-3rd Floor, Oxford Road, Manchester, M13 9PT, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Berry
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, AV Hill Building-3rd Floor, Oxford Road, Manchester, M13 9PT, United Kingdom.
authors.forename: Karen
authors.initials: K
authors.lastname: Piper-Hanley
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, AV Hill Building-3rd Floor, Oxford Road, Manchester, M13 9PT, United Kingdom.
authors.forename: Neil
authors.initials: N
authors.lastname: Hanley
authors.affiliation: Centre For Tissue Injury and Repair, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, United Kingdom.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Richardson
authors.affiliation: Centre For Tissue Injury and Repair, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, United Kingdom.|NIHR Manchester Musculoskeletal Biomedical Research Unit, Manchester Academic Health Science Centre, Manchester, United Kingdom.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Hoyland
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D051927:CD24 Antigen / Q000378:metabolism*; D006801:Humans; D007403:Intervertebral Disc / Q000196:embryology* / Q000378:metabolism; D007633:Keratins / Q000378:metabolism*; D009672:Notochord / Q000196:embryology* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D051927:CD24 Antigen; C497889:CD24 protein, human; D007633:Keratins
keywords: intervertebral disc degeneration; notochordal cells; nucleus pulposus; ontogeny; phenotype