title: Activating AMP-activated protein kinase by an α1 selective activator compound 13 attenuates dexamethasone-induced osteoblast cell death.
abstract: Excessive glucocorticoid (GC) usage may lead to non-traumatic femoral head osteonecrosis. Dexamethasone (Dex) exerts cytotoxic effect to cultured osteoblasts. Here, we investigated the potential activity of Compound 13 (C13), a novel α1 selective AMP-activated protein kinase (AMPK) activator, against the process. Our data revealed that C13 pretreatment significantly attenuated Dex-induced apoptosis and necrosis in both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts. AMPK activation mediated C13' cytoprotective effect in osteoblasts. The AMPK inhibitor Compound C, shRNA-mediated knockdown of AMPKα1, or dominant negative mutation of AMPKα1 (T172A) almost abolished C13-induced AMPK activation and its pro-survival effect in osteoblasts. On the other hand, forced AMPK activation by adding AMPK activator A-769662 or exogenous expression a constitutively-active (ca) AMPKα1 (T172D) mimicked C13's actions and inhibited Dex-induced osteoblast cell death. Meanwhile, A-769662 or ca-AMPKα1 almost nullified C13's activity in osteoblast. Further studies showed that C13 activated AMPK-dependent nicotinamide adenine dinucleotide phosphate (NADPH) pathway to inhibit Dex-induced reactive oxygen species (ROS) production in MC3T3-E1 cells and primary murine osteoblasts. Such effects by C13 were almost reversed by Compound C or AMPKα1 depletion/mutation. Together, these results suggest that C13 alleviates Dex-induced osteoblast cell death via activating AMPK signaling pathway.
authors.affiliation: Department of Intensive Care Unit, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.
authors.forename: Shiguang
authors.initials: S
authors.lastname: Guo
authors.affiliation: Department of Endocrinology, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.
authors.forename: Li
authors.initials: L
authors.lastname: Mao
authors.affiliation: Department of Orthopedics, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China. Electronic address: huaiaifengjidr@163.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Ji
authors.affiliation: Department of Orthopedics, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.
authors.forename: Shouguo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Orthopedics, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.
authors.forename: Haodong
authors.initials: H
authors.lastname: Fei
authors.affiliation: The Center of Diagnosis and Treatment for Children's Bone Diseases, The Children's Hospital Affiliated to Soochow University, Suzhou, China. Electronic address: xiaodongwangsz@163.com.
authors.forename: Xiao-dong
authors.initials: XD
authors.lastname: Wang
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D001713:Biphenyl Compounds; D002460:Cell Line; D003907:Dexamethasone / Q000009:adverse effects* / Q000037:antagonists & inhibitors; D004789:Enzyme Activation; D005938:Glucocorticoids / Q000009:adverse effects* / Q000037:antagonists & inhibitors; D051379:Mice; D009154:Mutation; D009249:NADP / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D061251:Primary Cell Culture; D011753:Pyrones / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013876:Thiophenes / Q000494:pharmacology
chemical_list: D001713:Biphenyl Compounds; D005938:Glucocorticoids; D011753:Pyrones; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D013876:Thiophenes; D009249:NADP; D003907:Dexamethasone; D055372:AMP-Activated Protein Kinases; C512408:4-hydroxy-3-(4-(2-hydroxyphenyl)phenyl)-6-oxo-7H-thieno(2,3-b)pyridine-5-carbonitrile
keywords: AMP-activated protein kinase (AMPK); Compound 13; Glucocorticoid; NADPH; Osteoblasts; Oxidative stresses