Hypoxia-inducible factor 1-α-AA-modified bone marrow stem cells protect PC12 cells from hypoxia-induced apoptosis, partially through VEGF/PI3K/Akt/FoxO1 pathway.

Abstract

Bone marrow stem cells (BMSCs) have been shown to improve neurological function recovery in cerebral ischemia. Hypoxia-inducible factor-1 (HIF-1) α-AA is a more stable mutant form of HIF-1α, which is a crucial oxygen-sensitive regulator. To investigate the protective effects of HIF-1α-AA-modified BMSCs on neuron survival in cerebral ischemia models, we co-cultured HIF-1α-AA-modified BMSCs with neuron-like cells (PC12 cells) and observed a significant increase in the release of vascular endothelial growth factor (VEGF) from BMSCs, the decreased PC12 cell apoptosis, and the upregulation of Survivin expression reduced by hypoxia in PC12 cells compared to enhanced green fluorescent protein (EGFP) BMSCs. In addition, to explore whether VEGF secreted by HIF-1α-AA-modified BMSCs plays an important role in preventing hypoxia-induced apoptosis and the possible mechanism involved, exogenous VEGF were applied and the similar protective effects on PC12 cells were observed in vitro. Furthermore, hypoxia reduced the expression of phosphorylated Akt and phosphorylated FoxO1, whereas the administration of VEGF reversed these changes. Transfection of FoxO1 H215R, a DNA-binding mutant, abrogated the inhibitory ability on Survivin promoter activity, whereas FoxO1 AAA, the active form of FoxO1, presented further repression on Survivin promoter, indicating that FoxO1 directly binds on Survivin promoter as a transcriptional repressor and that phosphorylation status of FoxO1 affects its inhibition on the Survivin promoter. Transplantation of HIF-1α-AA-modified BMSCs after cerebral ischemia in vivo sufficiently reduced neurons apoptosis, decreased cerebral infarction volume, and induced a significant improvement on the modified neurological severity score compared to the EGFP BMSCs group. In conclusion, HIF-1α-AA-modified MSCs showed an obvious protective effect on neuron-like cells or neuron after ischemia in vitro and in vivo, at least in part, through the VEGF/PI3K/Akt/FoxO1 pathway.

• Authors: Qian Zhong, Yanfang Zhou, Weibiao Ye, Tuo Cai, Xiuquan Zhang, David Y B Deng
• Journal: Stem cells and development (Stem Cells Dev) Vol. 21 Issue 14 Pg. 2703-17 (Sep 20 2012) ISSN: 1557-8534 [Electronic] United States
• PMID: 22468883 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Birc5 protein, rat
• Forkhead Transcription Factors
• Hypoxia-Inducible Factor 1, alpha Subunit
• Microtubule-Associated Proteins
• Nerve Tissue Proteins
• Survivin
• Vascular Endothelial Growth Factor A
• enhanced green fluorescent protein
• vascular endothelial growth factor A, rat
• Green Fluorescent Proteins
• Foxo1 protein, rat
• Cobalt
• Phosphatidylinositol 3-Kinases
• cobaltous chloride

Topics

• Animals
• Apoptosis
• Bone Marrow Cells (cytology, metabolism)
• Bone Marrow Transplantation (methods)
• Cell Hypoxia
• Cerebral Infarction (metabolism, therapy)
• Cobalt (adverse effects)
• Coculture Techniques
• Forkhead Transcription Factors (genetics, metabolism)
• Green Fluorescent Proteins (metabolism)
• Hypoxia-Inducible Factor 1, alpha Subunit (genetics, metabolism)
• Lentivirus (metabolism)
• Male
• Microtubule-Associated Proteins (genetics, metabolism)
• Nerve Tissue Proteins (genetics, metabolism)
• Neurons (metabolism)
• PC12 Cells
• Phosphatidylinositol 3-Kinases (metabolism)
• Phosphorylation
• Promoter Regions, Genetic
• Protein Binding
• Rats
• Rats, Sprague-Dawley
• Signal Transduction
• Stem Cells (cytology, metabolism)
• Survivin
• Transfection
• Vascular Endothelial Growth Factor A (metabolism, pharmacology)