Hyperglycemia and Advanced Glycation End Products Regulate miR-126 Expression in Endothelial Progenitor Cells.
OBJECTIVE
Dysfunction of endothelial progenitor cell (EPCs) contributes to diabetic vascular disease. We reported that downregulated miR-126 in diabetic patients causes EPC dysfunction. The study was designed to investigate how high glucose (HG) and advanced glycation end products (AGEs) regulate miR-126 expression and whether miR-126 mediates the effects of HG and AGEs on EPCs.


METHODS
We first tested the effects of glucose (5.5-50 mM) and AGEs at 50-200 mg/l on EPC proliferation and selected HG at 50 mM and AGEs at 50 mg/l for further experiments. EPCs were stimulated with HG and AGEs, and miR-126 expression was measured by real-time PCR. Reactive oxygen species (ROS) were measured by immunofluorescence microscopy and flow cytometry. IL-6 and TNF-α levels in EPC supernatants were determined by ELISA. The effects of miR-126 on ROS and inflammatory markers under stimulation of HG and AGEs were also assessed. Finally, the effects of inhibitors of PI3K and Akt on AGE-mediated miR-126 expression were examined.


RESULTS
HG and AGEs increased IL-6, TNF-α and ROS and decreased miR-126 expression in EPCs. miR-126 negatively regulated IL-6, TNF-α and ROS. miR-126 overexpression reduced and miR-126 inhibition further increased the inflammatory markers and ROS induced by HG and AGEs. Inhibitors of PI3K and Akt further decreased miR-126 expression in the presence of AGEs.


CONCLUSIONS
In conclusion, hyperglycemia and AGEs decrease miR-126 expression in EPCs. Recovering miR-126 expression may protect EPCs against dysfunction induced by HG and AGEs.
Department of Cardiology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.
Yeting
Y
Li
Qing
Q
Zhou
ChongZhe
C
Pei
Bo
B
Liu
MaoQuan
M
Li
Lu
L
Fang
YingGang
Y
Sun
YiGang
Y
Li
Shu
S
Meng
D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D066026:Endothelial Progenitor Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D025461:Feedback, Physiological; D005947:Glucose / Q000633:toxicity*; D017127:Glycation End Products, Advanced / Q000633:toxicity*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D017127:Glycation End Products, Advanced; D018836:Inflammation Mediators; D015850:Interleukin-6; C527111:MIRN126 microRNA, human; D035683:MicroRNAs; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C577686:interleukin-6, mouse; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose