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Hyperglycemia alters PI3k and Akt signaling and leads to endothelial cell proliferative dysfunction.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Varma, Shubha Zheng, Ruifang Breslin, Jerome W. Saito, Satoshi |
| Copyright Year | 2005 |
| Abstract | Diabetes mellitus is a major risk factor for the development of vascular complications. We hypothesized that hyperglycemia decreases endothelial cell (EC) proliferation and survival via phosphatidylinositol 3-kinase (PI3k) and Akt signaling pathways. We cultured human umbilical vein ECs (HUVEC) in 5, 20, or 40 mM d-glucose. Cells grown in 5, 20, and 40 mM mannitol served as a control for osmotic effects. We measured EC proliferation for up to 15 days. We assessed apoptosis by annexin V and propidium iodide staining and flow cytometry, analyzed cell lysates obtained on culture day 8 for total and phosphorylated PI3k and Akt by Western blot analysis, and measured Akt kinase activity using a GSK fusion protein. HUVEC proliferation was also tested in the presence of pharmacological inhibitors of PI3k-Akt (wortmannin and LY294002) and after transfection with a constitutively active Akt mutant. ECs in media containing 5 mM d-glucose (control) exhibited log-phase growth on days 7-10. d-Glucose at 20 and 40 mM significantly decreased proliferation versus control (P < 0.05 for both), whereas mannitol did not impair EC proliferation. Apoptosis increased significantly in HUVEC exposed to 40 mM d-glucose. d-Glucose at 40 mM significantly decreased tyrosine-phosphorylated PI3k, threonine 308-phosphorylated-Akt, and Akt activity relative to control 5 mM d-glucose. Pharmacological inhibition of PI3k-Akt resulted in a dose-dependent decrease in EC proliferation. Transfection with a constitutively active Akt mutant protected ECs by enhancing proliferation when grown in 20 and 40 mM d-glucose. We conclude that d-glucose regulates Akt signaling through threonine phosphorylation of Akt and that hyperglycemia-impaired PI3k-Akt signaling may promote EC proliferative dysfunction in diabetes. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://ajpheart.physiology.org/content/ajpheart/289/4/H1744.full.pdf |
| PubMed reference number | 15964918v1 |
| Volume Number | 289 |
| Issue Number | 4 |
| Journal | American journal of physiology. Heart and circulatory physiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 1-Phosphatidylinositol 3-Kinase Annexins Apoptosis Cerebrovascular Disorders Diabetes Mellitus Endothelial Cells Flow Cytometry Glucose Hyperglycemia Iodides L-Epicatechin Mannitol Pharmacology Propidium Iodide Proto-Oncogene Proteins c-akt Staining method Threonine Tyrosine Umbilical vein Umbilicus (Anatomy) Western Blot chimeric protein tau-protein kinase activity wortmannin |
| Content Type | Text |
| Resource Type | Article |
