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Rehae Miller, Maria Grant; Increased expression of Adenosine A2B receptor in endothelial precursor cells contributes to diabetes-induced dysfunction. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5604.
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© ARVO (1962-2015); The Authors (2016-present)
We examined Adenosine receptor type 2Ab (A2BAdoR) expression and activation in human endothelial progenitor cells (EPCs) expressing CD34+. We compared receptor expression levels in EPCs from individuals with diabetes, with and without diabetic retinopathy, as well as in human retinal endothelial cells (HREC), and examined the expression of a downstream molecule, cAMP.
Peripheral blood CD34+ cells were isolated from healthy donor and diabetic patients with and without proliferative diabetic retinopathy. Human retinal endothelial cells (HRECs) were isolated from retina of healthy donors. A2BAdoR protein expression levels in the CD34+ cells and HRECs were compared by Western blotting. The responses to the receptor activation in the cells were examined by quantifying HIF-1α and cAMP.
The expression of both A2BAdoR and HIF-1α was 5-fold higher in CD34+ cells in peripheral blood of diabetic patients than that of non-diabetic patients. A2BAdoR activation increased HIF-1α protein expression in HREC and CD34+ cells of control and diabetic patients. cAMP levels in CD34+ cells of diabetic patients were 2-fold lower than in those of healthy patients. The cAMP level was 1.5-fold higher in HRECs than in CD34+ cells of healthy patients.
Increased A2BAdoR expression in diabetic CD34+ cells may contribute to the “angiogenic switch”, leading to initiation of proliferative diabetic retinopathy, while decreased intracellular cAMP levels resulting from A2BAdoR activation likely contributes to cell dysfunction.
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