Functional Convergence of Akt Protein with VEGFR-1 in Human Endothelial Progenitor Cells Exposed to Sera from Patient with Type 2 Diabetes Mellitus

Background and Aim: Diabetes mellitus type 2 predisposes patients tovarious microvascular complicationsMethods: In the current experiment, the potent role of diabetes mellitus was investigated on the content of VEGFR-1, -2, Tie-1 and -2, and Aktin human endothelial progenitor cells. The gene expression profile ofmTOR and Hedgehog signaling pathways were measured by PCR array.The possible crosstalk between RTKs, mTOR and Hedgehog signalingwas also studied by bioinformatic analysis. Endothelial progenitor cellswere incubated with serum from normal and diabetic for 7 days.Results: Compared to non-treated cells, diabetic serum-induced cellapoptosis (~2-fold) and prohibited cell migration toward bFGF (P <0.001). ELISA analysis showed that diabetes exposed cells had increasedabundance of Tie-1, -2 and VEGFR-2 and a reduced amount of VEGFR-1 (P< 0.0001) in diabetic cells. Western blotting showed a marked reductionin the protein level of Akt after cells exposure to serum from diabeticsubjects (P < 0.0001). PCR array revealed a significant stimulation of bothmTOR and Hedgehog signaling pathways in diabetic cells (P < 0.05).According to data from bioinformatic datasets, we showed VEGFR-1, -2and Tie-2, but not Tie-1, are master regulators of angiogenesis.Conclusion: There is a crosstalk between RTKs and mTOR signalingby involving P62, GABARAPL1, and HTT genes. It seems that physicalinteraction and co-expression of Akt decreased the level of VEGFR-1in diabetic cells. Regarding data from the present experiment, diabeticserum contributed to uncontrolled induction of both mTOR andHedgehog signaling in endothelial progenitor cells. Diabetes mellitusinduces mTOR pathway by involving receptor tyrosine kinases whileHedgehog stimulation is independent of these receptors.

کلیدواژه ها:

Human endothelial progenitor cells ، Diabetes mellitus ، Receptor tyrosine kinases ، mTOR and Hedgehog signaling pathways