title: The effect of transforming growth factor β1 on the crosstalk between autophagy and apoptosis in the annulus fibrosus cells under serum deprivation.
abstract: Autophagy and apoptosis are important in maintaining the metabolic homeostasis of intervertebral disc cells, and transforming growth factor-β1 (TGF-β1) is able to delay intervertebral disc degeneration. This study determined the effect of TGF-β1 on the crosstalk between autophagy and apoptosis in the disc cells, with the aim to provide molecular mechanism support for the prevention and treatment of disc degeneration. Annulus fibrosus (AF) cells were isolated and cultured under serum starvation. 10 ng/mL TGF-β1 reduced the apoptosis incidence in the cells under serum starvation for 48 h, down-regulated the autophagy incidence in the cells pretreated with 3-methyladenine (3-MA) or Bafilomycin A (Baf A), partly rescued the increased apoptosis incidence in the cells pretreated with 3-MA, while further reduced the decreased apoptosis incidence in the cells pretreated with Baf A. Meanwhile, TGF-β1 down-regulated the expressions of autophagic and apoptotic markers in the cells under starvation, partly down-regulated the expressions of Beclin-1, LC3 II/I and cleaved caspase-3 in the cells pretreated with 3-MA or Baf A, while significantly decreased the expression of Bax/Bcl-2 in the cells pretreated with Baf A. 3-MA blocked the phosphorylation of both AKT and mTOR and partly reduced the inhibitory effect of TGF-β1 on the expression of LC3 II/I and cleaved caspase-3. TGF-β1 enhanced the expression of p-ERK1/2 and down-regulated the expressions of LC3 II/I and cleaved caspase-3. U0126 partly reversed this inhibitory effect of TGF-β1. In conclusion, TGF-β1 protected against apoptosis of AF cells under starvation through down-regulating excessive autophagy. PI3K-AKT-mTOR and MAPK-ERK1/2 were the possible signaling pathways involved in this process.
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Ni
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Yang
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Jiang-Wei
authors.initials: JW
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
authors.forename: Sheng-Dan
authors.initials: SD
authors.lastname: Jiang
authors.affiliation: Department of Orthopedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China. Electronic address: jiangleisheng@126.com.
authors.forename: Lei-Sheng
authors.initials: LS
authors.lastname: Jiang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D016895:Culture Media, Serum-Free; D019610:Cytoprotection / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D007403:Intervertebral Disc / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010588:Phagosomes / Q000187:drug effects / Q000648:ultrastructure; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
chemical_list: D016895:Culture Media, Serum-Free; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D053773:Transforming Growth Factor beta1
keywords: Apoptosis; Autophagy; Disc degeneration; Serum deprivation; TGF-β1