title: Integrin-mediated interactions with extracellular matrix proteins for nucleus pulposus cells of the human intervertebral disc.
abstract: The extracellular matrix (ECM) of the human intervertebral disc is rich in molecules that interact with cells through integrin-mediated attachments. Porcine nucleus pulposus (NP) cells have been shown to interact with laminin (LM) isoforms LM-111 and LM-511 through select integrins that regulate biosynthesis and cell attachment. Since human NP cells lose many phenotypic characteristics with age, attachment and interaction with the ECM may be altered. Expression of LM-binding integrins was quantified for human NP cells using flow cytometry. The cell-ECM attachment mechanism was determined by quantifying cell attachment to LM-111, LM-511, or type II collagen after functionally blocking specific integrin subunits. Human NP cells express integrins β1, α3, and α5, with over 70% of cells positive for each subunit. Blocking subunit β1 inhibited NP cell attachment to all substrates. Blocking subunits α1, α2, α3, and α5 simultaneously, but not individually, inhibits NP cell attachment to laminins. While integrin α6β1 mediated porcine NP cell attachment to LM-111, we found integrins α3, α5, and β1 instead contributed to human NP cell attachment. These findings identify integrin subunits that may mediate interactions with the ECM for human NP cells and could be used to promote cell attachment, survival, and biosynthesis in cell-based therapeutics.
authors.affiliation: Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, North Carolina 27708, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Bridgen
authors.forename: C L
authors.initials: CL
authors.lastname: Gilchrist
authors.forename: W J
authors.initials: WJ
authors.lastname: Richardson
authors.forename: R E
authors.initials: RE
authors.lastname: Isaacs
authors.forename: C R
authors.initials: CR
authors.lastname: Brown
authors.forename: K L
authors.initials: KL
authors.lastname: Yang
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: L A
authors.initials: LA
authors.lastname: Setton
mesh_terms: D000328:Adult; D000818:Animals; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D039421:Integrin alpha2 / Q000378:metabolism; D039422:Integrin alpha3 / Q000378:metabolism; D039121:Integrin alpha6beta1 / Q000378:metabolism; D039564:Integrin alphaV / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D039661:Integrin beta3 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism*; D007405:Intervertebral Disc Displacement / Q000378:metabolism* / Q000473:pathology; D007797:Laminin / Q000378:metabolism; D013552:Swine
chemical_list: D016326:Extracellular Matrix Proteins; D039421:Integrin alpha2; D039422:Integrin alpha3; D039121:Integrin alpha6beta1; D039564:Integrin alphaV; D019012:Integrin beta1; D039661:Integrin beta3; D016023:Integrins; D007797:Laminin
keywords: extracellular matrix; human; intervertebral disc; nucleus pulposus, integrin