title: Approximating bone ECM: Crosslinking directs individual and coupled osteoblast/osteoclast behavior.
abstract: Osteoblast and osteoclast communication (i.e. osteocoupling) is an intricate process, in which the biophysical profile of bone ECM is an aggregate product of their activities. While the effect of microenvironmental cues on osteoblast and osteoclast maturation has been resolved into individual variables (e.g. stiffness or topography), a single cue can be limited with regards to reflecting the full biophysical scope of natural bone ECM. Additionally, the natural modulation of bone ECM, which involves collagenous fibril and elastin crosslinking via lysyl oxidase, has yet to be reflected in current synthetic platforms. Here, we move beyond traditional substrates and use cell-derived ECM to examine individual and coupled osteoblast and osteoclast behavior on a physiological platform. Specifically, preosteoblast-derived ECM is crosslinked with genipin, a biocompatible crosslinker, to emulate physiological lysyl oxidase-mediated ECM crosslinking. We demonstrate that different concentrations of genipin yield changes to ECM density, stiffness, and roughness while retaining biocompatibility. By approximating various bone ECM profiles, we examine how individual and coupled osteoblast and osteoclast behavior are affected. Ultimately, we demonstrate an increase in osteoblast and osteoclast differentiation on compact and loose ECM, respectively, and identify ECM crosslinking density as an underlying force in osteocoupling behavior.
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Mintai P
authors.initials: MP
authors.lastname: Hwang
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Subbiah
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
authors.forename: In Gul
authors.initials: IG
authors.lastname: Kim
authors.affiliation: Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
authors.forename: Kyung Eun
authors.initials: KE
authors.lastname: Lee
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
authors.forename: Jimin
authors.initials: J
authors.lastname: Park
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
authors.forename: Sang Heon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea. Electronic address: kpark@kist.re.kr.
authors.forename: Kwideok
authors.initials: K
authors.lastname: Park
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D003432:Cross-Linking Reagents / Q000378:metabolism; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D039823:Iridoids / Q000378:metabolism; D008422:Materials Testing; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D008249:Protein-Lysine 6-Oxidase / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D016326:Extracellular Matrix Proteins; D039823:Iridoids; C077112:Lox protein, mouse; C007834:genipin; D008249:Protein-Lysine 6-Oxidase
keywords: ECM; Genipin; LOX; Osteoblast; Osteoclast; Osteocoupling