title: [Activation of endoplasmic reticulum stress and its effect on osteogenic differentiation induced by micropit/nanotube topography].
abstract: Objective:To explore the activation of endoplasmic reticulum stress (ERS) in bone marrow mesenchymal stem cell (BMMSC) and its effect on osteogenic differentiation induced by micropit/nanotube topography (MNT), so as to provide guidance for the topography design of biomaterials.Methods:Four sample groups were fabricated: polishing control group (polished titanium, PT, no treatment), thapsigargin treatment (TG, 0.1 μmol/L TG treated for 9 h), MNT5 and MNT20 (anodized at 5 V and 20 V after acid etching). Scanning electron microscope (SEM) was used to observe the topography of Ti samples. The alkaline phosphatase (ALP) production, collagen secretion and extracellular matrix (ECM) mineralization of BMMSC (osteogenic induced for 7, 14 and 21 d) on Ti samples were detected to evaluate the osteogenic differentiation. After 12 h incubation, the shape and size of ER was examined using a transmission electron microscope (TEM), and ERS-related genes including immunoglobulin heavy chain binding protein (BiP), protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activating transcription factor 4 (ATF4) were detected by quantitative real-time PCR (qRT-PCR).Results:After 7, 14 and 21 d of induction, the ALP production, collagen secretion and ECM mineralization in TG and MNT20 all significantly increased compared to PT (P<0.05). The cells grown on TG, MNT5 and MNT20 surfaces displayed gross distortions of the ER. Compared to PT, BiP, PERK, ATF4 mRNA expression in TG was respectively 1.87±0.10, 2.24±0.35, 1.85±0.14; BiP, ATF4 mRNA expression in MNT5 were respectively 1.27±0.09, 1.25±0.04; BiP, PERK, ATF4 mRNA expression in MNT20 were respectively 1.44±0.09, 2.40±0.60, 1.48±0.05 (P<0.05).Conclusions:MNT triggered different degree of ERS, and the activated ERS may promote MNT-induced osteogenic differentiation.
authors.affiliation: Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Xi'an 710032, China.
authors.forename: M Q
authors.initials: MQ
authors.lastname: Shi
authors.affiliation: Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Xi'an 710032, China.
authors.forename: W
authors.initials: W
authors.lastname: Song
authors.affiliation: Department of Prosthodontics, Capital Medical University School of Stomatology, Beijing 100050, China.
authors.forename: T X
authors.initials: TX
authors.lastname: Han
authors.affiliation: Department of Stomatology, PLA Rocket Force General Hospital, Beijing 100088, China.
authors.forename: B
authors.initials: B
authors.lastname: Chang
authors.affiliation: Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Xi'an 710032, China.
authors.forename: Y M
authors.initials: YM
authors.lastname: Zhang
mesh_terms: D051701:Activating Transcription Factor 4 / Q000235:genetics / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D002113:Calcification, Physiologic; D002454:Cell Differentiation / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D006360:Heat-Shock Proteins; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes; D010012:Osteogenesis / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: D051701:Activating Transcription Factor 4; D000469:Alkaline Phosphatase; D003094:Collagen; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D019284:Thapsigargin; D019892:eIF-2 Kinase
keywords: Endoplasmic reticulum stress; Mesenchymal stem cells; Nanotubes; Titanium