CREG promotes vasculogenesis by activation of VEGF/PI3K/Akt pathway

Abstract

Knowledge about factors regulating vasculogenesis remains limited. The cellular repressor of E1A-stimulated gene (CREG) has been reported to be involved in maintaining cellular differentiation and endothelial homeostasis, thus we hypothesize that CREG may be a novel factor regulating vasculogenesis. By using mouse embryonic stem cells (ESC) derived embryoid body (EB) model, we confirmed expression of CREG was significantly up-regulated during EB differentiation. Overexpression of CREG in ESC led to accelerated cystic EB formation, increased endothelial differentiation and vasculogenesis, whereas knockdown of CREG produced opposite phenotypes. Moreover, we found expression of vascular endothelial growth factor (VEGF) was up-regulated and PI3K/Akt pathway was activated in CREG-overexpressing EB. Administration of VEGF neutralizing antibody or PI3K/Akt pharmacological inhibitor LY294002 blocked the vasculogenesis in CREG over-expressing EB, while supplement of VEGF rescued vasculogenesis deficiency in CREG knocked down EB. Further study by Western blot determined that PI3K/Akt was a downstream effector of VEGF. We identify CREG as a novel factor in regulating endothelial differentiation and vasculogenesis via VEGF/PI3K/Akt pathway.

Etv6 activates vegfa expression through positive and negative transcriptional regulatory networks in Xenopus embryos

“…Indeed, many of the TFs and chromatin modifiers identified amongst Etv6’s 540 direct target genes have previously been directly or indirectly implicated in the regulation of VegfA in endothelial and cancer cells. In addition to Foxo3 and Klf4 (the two targets examined in this study), these are Ets2, shown to down-regulate VegfA expression in HUVECs treated with arsenic trioxide (ATO) 39 , the tumour suppressor Rbl2 (also known as RB2/p130), that inhibits tumour formation in mice by inhibiting VegfA-mediated angiogenesis 37 , the transcriptional repressor Mecp2, that represses VegfA expression by binding to methylated CpG islands in the VegfA promoter 35 , and the transcriptional regulator Creg1, that regulates human endothelial homoeostasis in vivo and promotes vasculogenesis in mouse ES cells through the activation of VegfA 36 . These findings validate our experimental design and the robustness of the list of Etv6’s direct target genes.…”

Effect of Azelaic Acid on Psoriasis Progression Investigated Based on Phosphatidylinositol 3-Kinase (PI3K)/Protein Kinase B (AKT) Signaling Pathway

“… 37 VEGF and angiogenin-1 are also important upstream molecules of PI3K/AKT signaling pathway. 38 , 39 Moreover, activation of the PI3K/AKT signaling pathway can also regulate the expression of VEGF and angiopoietin. 28 In this study, azelaic acid could not only regulate the expression of p-PI3K, p-AKT, p-mTOR, but also the expression of VEGF, COX-2, angiogenin-1 and HIF-1α.…”

Proteome Changes during Transition from Human Embryonic to Vascular Progenitor Cells

“…This implies that the CD34 + population is undoubtedly the one that eventually differentiates to endothelial cells. Among the few proteins with increased abundance in CD34 − that might be involved in vasculogenesis were CREG1 74 LUM 75 and the LRP1 76 (Figure 4E, Supporting Table S-7). Interestingly, CREG1 and LUM are secreted, and LRP1 is cleaved 77 generating a soluble fragment.…”

“…In the CD34 – cells, we have identified five proteins with increased abundance (CD140B, PALLD, CREG1, LRP1, DAG1; Figure E) that are synthesized in vascular smooth muscle cells (VSMCs) or play a role in their differentiation and the proper investment of both large and small vessels with mural cells. ,,− Importantly, hiPSCs-derived contractile and functional SMCs were CD34 – indicating that both types of progenitor stem cell (CD34 + and CD34 – ) have the machinery to differentiate SMCs/PCs. This is in agreement with the fact that during development, VSMCs arise from multiple independent origins or different subsets of mesoderm-committed cells …”