4-Phenyl butyric acid prevents glucocorticoid-induced osteoblast apoptosis by attenuating endoplasmic reticulum stress.
Apoptosis of osteoblasts triggered by high-dose glucocorticoids (GCs) has been identified as a major cause of osteoporosis. However, the molecular mechanisms underlying GC-induced osteoporosis remain elusive. This study was conducted to make clear the mechanism of GC-induced osteoblast apoptosis and to examine whether reduction of ER stress by 4-PBA inhibited osteoblast apoptosis. After treatment with dexamethasone (Dex) or hydrocortisone, cell viability was assessed using an MTT assay. Flow cytometry was performed to assess the apoptosis of MC3T3-E1 cells. The expression levels of ER stress-related proteins (CHOP, GRP78, eIF2α, and phospho-eIF2α) and apoptosis-related proteins (cleaved Caspase-3, Bcl-2, and Bax) in MC3T3-E1 cells were measured by Western blot analysis. We found that both Dex and hydrocortisone reduced cell proliferation and promoted apoptosis in MC3T3-E1 cells. In addition, the protein expression levels of cleaved Caspase-3 and Bax increased and the protein expression level of Bcl-2 decreased in MC3T3-E1 cells exposed to Dex. In addition, the Dex exposure also resulted in a release of cytochrome c (Cyt C) from mitochondria. The cellular ATP content was decreased following prolonged treatment with Dex. 4-PBA attenuated ER stress and mitochondrial dysfunction induced by Dex in MC3T3-E1 cells. Dex-mediated apoptosis of MC3T3-E1 cells is aggravated by ER stress. Moreover, Dex-induced apoptosis in MC3T3-E1 cells was inhibited by 4-PBA, suggesting that ER stress involved in Dex-induced apoptosis. In conclusion, inhibition of ER stress by 4-PBA could reduce GC-induced apoptosis in MC3T3-E1 cells.
Rehabilitation Center, The First Affiliated Hospital of Health Science Center, Xi'an Jiaotong University, No 277 Yanta West Road, Xi'an, 710061, Shaanxi Province, China. yangjhdoc@163.com.
Jianhui
J
Yang
Rehabilitation Center, The First Affiliated Hospital of Health Science Center, Xi'an Jiaotong University, No 277 Yanta West Road, Xi'an, 710061, Shaanxi Province, China.
Qiong
Q
Wu
Rehabilitation Center, The First Affiliated Hospital of Health Science Center, Xi'an Jiaotong University, No 277 Yanta West Road, Xi'an, 710061, Shaanxi Province, China.
Jianguo
J
Lv
Rehabilitation Center, The First Affiliated Hospital of Health Science Center, Xi'an Jiaotong University, No 277 Yanta West Road, Xi'an, 710061, Shaanxi Province, China.
Huiyong
H
Nie
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002082:Butylamines / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D003907:Dexamethasone / Q000009:adverse effects; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D010654:Phenylbutyrates / Q000494:pharmacology*; D019284:Thapsigargin / Q000494:pharmacology
C121358:4-phenylbutylamine; D002082:Butylamines; D000091342:Endoplasmic Reticulum Chaperone BiP; D005938:Glucocorticoids; C000717247:HSPA5 protein, human; C000717248:Hspa5 protein, mouse; D010654:Phenylbutyrates; D019284:Thapsigargin; D003907:Dexamethasone; C075773:4-phenylbutyric acid; D053148:Caspase 3
4-Phenylbutyric acid; Endoplasmic reticulum stress; Glucocorticoid; Osteoblasts
Pharmacol Ther. 2012 Jun;134(3):306-16
22387231
Nature. 2008 Jul 24;454(7203):455-62
18650916
Invest Ophthalmol Vis Sci. 2007 Apr;48(4):1683-90
17389500
PLoS Biol. 2010 Jul 06;8(7):e1000415
20625545
Science. 2006 Aug 25;313(5790):1137-40
16931765
EMBO Rep. 2006 Sep;7(9):880-5
16953201
Science. 2011 Sep 30;333(6051):1891-4
21852455
Nat Cell Biol. 2000 Jun;2(6):326-32
10854322
J Bone Miner Metab. 2013 May;31(3):274-84
23263781
Oncogene. 2013 Apr 11;32(15):1933-42
22689054
PLoS One. 2014 Feb 10;9(2):e88389
24520378
Free Radic Res. 2011 Jun;45(6):692-8
21417786
Exp Ther Med. 2013 May;5(5):1289-1292
23737866
Science. 2005 Feb 11;307(5711):935-9
15705855
Rheumatology (Oxford). 2001 Jan;40(1):74-83
11157145
J Clin Invest. 2006 Aug;116(8):2152-60
16878176
J Biol Chem. 2005 Apr 8;280(14 ):14189-202
15684420
J Bone Miner Res. 2014 Nov;29(11):2520-6
24771492
Calcif Tissue Int. 2014 Jun;94(6):640-7
24658772
J Biochem. 2012 Mar;151(3):217-9
22210905
Nat Rev Mol Cell Biol. 2012 Jan 18;13(2):89-102
22251901
Cell Death Dis. 2012 Jan 26;3:e261
22278288
Biol Trace Elem Res. 2015 Mar;164(1):64-71
25434583
J Bone Miner Metab. 2012 Jul;30(4):474-84
22222420
Autophagy. 2014 Oct 1;10 (10 ):1801-13
25126734
Cell Death Differ. 2008 Sep;15(9):1460-71
18551133
Biochim Biophys Acta. 2013 Dec;1833(12 ):3460-3470
23850759
Cell Metab. 2010 Jun 9;11(6):517-31
20519123
J Endocrinol. 2007 Nov;195(2):229-40
17951534
Nat Cell Biol. 2000 Mar;2(3):156-62
10707086
Bone. 2006 May;38(5):652-61
16298558
J Clin Invest. 2012 Nov;122(11):4172-89
23093779
J Clin Invest. 2009 May;119(5):1201-15
19363290
J Bone Miner Metab. 2009;27(2):140-8
19066717
J Lipid Res. 2009 Dec;50(12 ):2486-501
19461119
Bone. 2015 Apr;73:60-8
25532480