title: Methylprednisolone inhibits the proliferation and affects the differentiation of rat spinal cord-derived neural progenitor cells cultured in low oxygen conditions by inhibiting HIF-1α and Hes1 in vitro.
abstract: Although there is much controversy over the use of methylprednisolone (MP), it is one of the main drugs used in the treatment of acute spinal cord injury (SCI). The induction of the proliferation and differentiation of endogenous neural progenitor cells (NPCs) is considered a promising mode of treatment for SCI. However, the effects of MP on spinal cord-derived endogenous NPCs in a low oxygen enviroment remain to be delineated. Thus, the aim of this study was to investigate the potential effects of MP on NPCs cultured under low oxygen conditions in vitro and to elucidate the molecular mechanisms involved. Fetal rat spinal cord-derived NPCs were harvested and divided into 4 groups: 2 groups of cells cultured under normal oxygen conditions and treated with or without MP, and 2 groups incubated in 3% O2 (low oxygen) treated in a similar manner. We found that MP induced suppressive effects on NPC proliferation even under low oxygen conditions (3% O2). The proportion of nestin-positive NPCs decreased from 51.8±2.46% to 36.17±3.55% following the addition of MP and decreased more significantly to 27.20±2.68% in the cells cultured in 3% O2. In addition, a smaller number of glial fibrillary acidic protein (GFAP)-positive cells and a greater number of microtubule-associated protein 2 (MAP2)-positive cells was observed following the addition of MP under both normal (normoxic) and low oxygen (hypoxic) conditions. In response to MP treatment, hypoxia-inducible factor-1α (HIF-1α) and the Notch signaling pathway downstream protein, Hes1, but not the upstream Notch-1 intracelluar domain (NICD), were inhibited. After blocking NICD with a γ-secretase inhibitor (DAPT) MP still inhibited the expression of Hes1. Our results provide insight into the molecular mechanisms responsible for the MP-induced inhibition of proliferation and its effects on differentiation and suggest that HIF-1α and Hes1 play an important role in this effect.
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Wenhao
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong 528000, P.R. China.
authors.forename: Shiyuan
authors.initials: S
authors.lastname: Li
authors.affiliation: Biotherapy Center, Sun Yat-sen Memorial Hospital, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Jiewen
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Xinjun
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.affiliation: Biotherapy Center, Sun Yat-sen Memorial Hospital, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Orthopedics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Shen
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D015687:Cell Hypoxia; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D018398:Homeodomain Proteins / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D008775:Methylprednisolone / Q000494:pharmacology*; D064231:Nestin / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*; D010735:Phosphoglycerate Kinase / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013116:Spinal Cord / Q000166:cytology*; D000072056:Transcription Factor HES-1; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D018398:Homeodomain Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008775:Methylprednisolone; D064231:Nestin; D010100:Oxygen; D010735:Phosphoglycerate Kinase; D051880:Receptors, Notch; D000072056:Transcription Factor HES-1; D042461:Vascular Endothelial Growth Factor A; C489735:Hes1 protein, rat