Quantitative proteomic analysis of dexamethasone-induced effects on osteoblast differentiation, proliferation, and apoptosis in MC3T3-E1 cells using SILAC
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The impairment of osteoblast differentiation is one cause of the glucocorticoid-induced osteoporosis (GCOP). The quantitative proteomic analysis of the dexamethasone (DEX)-induced effects of osteoblast differentiation, proliferation, and apoptosis using stable-isotope labeling by amino acids in cell culture (SILAC) demonstrated drastic changes of some key proteins in MC3T3-E1 cells.
The impairment of osteoblast differentiation is one of the main explanations of GCOP. SILAC enables accurate quantitative proteomic analysis of protein changes in cells to explore the underlying mechanism of GCOP.
Osteoprogenitor MC3T3-E1 cells were treated with or without 10−6 M DEX for 7 days, and the differentiation ability, proliferation, and apoptosis of the cells were measured. The protein level changes were analyzed using SILAC and liquid chromatography-coupled tandem mass spectrometry.
In this study, 10−6 M DEX inhibited both osteoblast differentiation and proliferation but induced apoptosis in osteoprogenitor MC3T3-E1 cells on day 7. We found that 10−6 M DEX increased the levels of tubulins (TUBA1A, TUBB2B, and TUBB5), IQGAP1, S100 proteins (S100A11, S100A6, S100A4, and S100A10), myosin proteins (MYH9 and MYH11), and apoptosis and stress proteins, while inhibited the protein levels of ATP synthases (ATP5O, ATP5H, ATP5A1, and ATP5F1), G3BP-1, and Ras-related proteins (Rab-1A, Rab-2A, and Rab-7) in MC3T3-E1 cells.
Several members of the ATP synthases, myosin proteins, small GTPase superfamily, and S100 proteins may participate in functional inhibition of osteoblast progenitor cells by GCs. Such protein expression changes may be of pathological significance in coping with GCOP.
KeywordsApoptosis Dexamethasone Osteoblast differentiation Proliferation Proteomics SILAC
Actin, alpha skeletal muscle
Actin, cytoplasmic 1
ATP synthase subunit alpha, mitochondrial precursor
ATP synthase B chain, mitochondrial precursor
ATP synthase D chain, mitochondrial
ATP synthase O subunit, mitochondrial precursor
Apoptosis regulator BAX
Ras GTPase-activating protein-binding protein 1
Heat shock 70 kDa protein 4
Heat shock protein HSP 90-alpha
Ras GTPase-activating-like protein 1
Integrator complex subunit 3
Stable-isotope labeling by amino acids in cell culture
Tubulin alpha-1 chain
Tubulin beta-2B chain
Tubulin beta-5 chain
Liquid chromatography-coupled tandem mass spectrometry
Myb-binding protein 1A
Isoform 1 of myosin 11
Programmed cell death 6-interacting protein
Programmed cell death 6
Protein Interrogation of Gene Ontology and KEGG databases
Polymerase I and transcript release factor
Peptidylprolyl isomerase B
Transitional endoplasmic reticulum ATPase