Angiopoietin-like 4 confers resistance to hypoxia/serum deprivation-induced apoptosis through PI3K/Akt and ERK1/2 signaling pathways in mesenchymal stem cells.
Angiopoietin-like 4 (ANGPTL4) is a potential anti-apoptotic agent for various cells. We examined the protective effect of ANGPTL4 on hypoxia/serum deprivation (SD)-induced apoptosis of MSCs, as well as the possible mechanisms. MSCs were obtained from rat bone marrow and cultured in vitro. Apoptosis was induced by hypoxia/SD for up to 24 hr, and assessed by flow cytometry and TUNEL assay. Expression levels of Akt, ERK1/2, focal adhesion kinase (FAK), Src, Bcl-2, Bax, cytochrome C and cleaved caspase-3 were detected by Western blotting. Integrin β1 mRNA was detected by qRT-PCR. Mitochondrial membrane potential was assayed using a membrane-permeable dye. Hypoxia/SD-induced apoptosis was significantly attenuated by recombinant rat ANGPTL4 in a concentration dependent manner. Moreover, ANGPTL4 decreased the hypoxia/SD-induced caspase-3 cleavage and the cytochrome C release, but increased the Bcl-2/Bax ratio and the mitochondrial membrane potential. Decreased expression of integrin β1, the ANGPTL4 receptor was observed during hypoxia/SD conditions, however, such decrease was reversed by ANGPTL4. In addition, ANGPTL4 induced integrin β1-associated FAK and Src phosphorylation, which was blocked by anti-integrin β1 antibody. ANGPTL4 also reversed the hypoxia/SD-induced decrease of Akt and ERK 1/2 phosphorylation, and the effect of ANGPTL4 was abolished by inhibitors of either integrins, ERK1/2, or phosphatidylinositol 3-kinase (PI3K). Blocking integrinβ1, Akt or ERK largely attenuated anti-apoptotic effect of ANGPTL4. ANGPTL4 protects MSCs from hypoxia/SD-induced apoptosis by interacting with integrins to stimulate FAK complex, leading to downstream ERK1/2 and PI3K/Akt signaling pathways and mimicking the pathway in which MSCs contact with the extracellular matrix.
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Meng
M
Hou
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Jinjin
J
Cui
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Jingjin
J
Liu
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Fang
F
Liu
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Rui
R
Jiang
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Kai
K
Liu
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Yongshun
Y
Wang
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Li
L
Yin
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Intensive Care Unit (ICU) Department, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Wenhua
W
Liu
Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, Province Heilongjiang, China ; Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Province Heilongjiang, China.
Bo
B
Yu
D000075803:Angiopoietin-Like Protein 4; D042682:Angiopoietins / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D019610:Cytoprotection / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
C528241:ANGPTL4 protein, rat; D000075803:Angiopoietin-Like Protein 4; D042682:Angiopoietins; D016895:Culture Media, Serum-Free; D019012:Integrin beta1; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases