title: Catabolic effects of endothelial cell-derived microparticles on disc cells: Implications in intervertebral disc neovascularization and degeneration.
abstract: Neovascularization of intervertebral discs, a phenomenon considered pathological since normal discs are primarily avascular structures, occurs most frequently in annulus fibrosus (AF) of degenerated discs. Endothelial cells (ECs) are involved in this process, but the mechanism of the interaction between AF and endothelial cells is unclear. In this study, we evaluated the effects on matrix catabolic activity of AF cells by the extracellular endothelial microparticles (EMPs) and soluble protein factors (SUP fraction) produced from ECs. Passage 1 human AF cells grown in monolayer cultures were treated for 72 h with 250 µg of EMPs or SUP fraction isolated from culture of the microvascular endothelial cell line, HEMC-I. Live-cell imaging revealed uptake of EMPs by AF cells. RT-PCR analysis demonstrated increased mRNA expression of MMP-1 (50.3-fold), MMP-3 (4.5-fold) and MMP-13 (5.5-fold) in AF cell cultures treated with EMPs compared to untreated control. Western analysis also demonstrated increased MMP protein expression in EMP-treated AF cells. AF cells treated with the SUP fraction also exhibited a dramatic increase in MMP mRNA and protein expression. Increased MMP expression is primarily due to EMP or SUP stimulation of AF cells since EMPs or SUP fraction alone contained negligible amount of MMPs. Interestingly, MMP activity was elevated in AF cell cultures treated with EMPs but not with SUP. This study revealed enhanced matrix catabolism as a molecular consequence of action of ECs on AF cells via EMPs, which might be expected during neo-angiogenesis of degenerating disc. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1466-1474, 2016.
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.|Spine Surgery Group, Discipline of Orthopaedic Surgery and Traumatology, ABC Medical School (FMABC), Sao Paulo, Brazil.
authors.forename: Pedro H I
authors.initials: PH
authors.lastname: Pohl
authors.affiliation: Center for Cellular and Molecular Engineering, University of Pittsburgh School of Medicine, Pittsburgh.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Lozito
authors.affiliation: Center for Cellular and Molecular Engineering, University of Pittsburgh School of Medicine, Pittsburgh.
authors.forename: Thais
authors.initials: T
authors.lastname: Cuperman
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.|Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yurube
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.|Department of Neurosurgery, College of Medicine, Korea University, Seoul, Republic of Korea.
authors.forename: Hong J
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.
authors.forename: Kevin
authors.initials: K
authors.lastname: Ngo
authors.affiliation: Center for Cellular and Molecular Engineering, University of Pittsburgh School of Medicine, Pittsburgh.
authors.forename: Rocky S
authors.initials: RS
authors.lastname: Tuan
authors.affiliation: Center for Biologic Imaging, Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Claudette
authors.initials: C
authors.lastname: St Croix
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.|Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Gwendolyn A
authors.initials: GA
authors.lastname: Sowa
authors.affiliation: Spine Surgery Group, Discipline of Orthopaedic Surgery and Traumatology, ABC Medical School (FMABC), Sao Paulo, Brazil.
authors.forename: Luciano M R
authors.initials: LM
authors.lastname: Rodrigues
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.
authors.forename: James D
authors.initials: JD
authors.lastname: Kang
authors.affiliation: Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic and Spine Research, University of Pittsburgh School of Medicine, Pittsburgh 15261, Pennsylvania.
authors.forename: Nam V
authors.initials: NV
authors.lastname: Vo
mesh_terms: D000070616:Annulus Fibrosus / Q000378:metabolism*; D002460:Cell Line; D055252:Cell-Derived Microparticles; D042783:Endothelial Cells / Q000502:physiology*; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000209:etiology* / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008875:Middle Aged; D009389:Neovascularization, Pathologic
chemical_list: D020782:Matrix Metalloproteinases
keywords: endothelial cells; intervertebral disc degeneration; matrix metalloproteinases; microparticles; neo-angiogenesis