The Effect Of Methylseleninic Acid On Angiogenesis And Endothelial Integrity

Selenium, as a micronutrient, has an influence on vascular endothelium function and homeostasis, but the active form of selenium is still unclear. Recent study showed that Methylseleninic Acid(MSA), as a mesostate of selenium, plays important roles on apoptosis and PI3K/AKT pathway. In this assay, tubular structure formation assay, mouse aortic ring assay and chick embryo chorioallantoic(CAM) assay were employed to evaluate the inhibition effect of MSA on angiogenesis. We also utilized HUVEC(Human Umbilical Vein Endothelial Cell) to study the anti-angiogenic mechanism in vitro. Monolayer endothelial cell model was employed to evaluate the effect of MSA on endothelium integrity and to study the mechanism. Additionally, we also study the effect of MSA on LDL(low density lipoprotein) uptake by using Raw 264.7 and BMDM(Bone Marrow-Derived Macrophage). The main results were shown as follow:1. Our results showed that MSA could increase the cell adherence to Rat tail collagen I, but inhibit cell migration and tubular structure formation of HUVECs in vitro. Meanwhile, we found that MSA could inhibit sprouts of mouse aortic rings ex vivo and neoangiogenesis in a chick embryo chorioallantoic membrane(CAM) model in vivo, which suggest that MSA could inhibit angiogenesis.2. HUVECs were employed to study the mechanism of MSA on angiogenesis, and the results showed that treating with 2 μM MSA did not induce apoptosis of HUVECs. QPCR and Western blot results showed that MSA could down-regulate integrin β3 in a time and dose dependent manner. Additionally, MSA could also inhibit the phosphorylation cascade of AKT/IκB/NF-κB and the nuclear translocation of NF-κB in a short time. Moreover, immunofluorescence results showed that MSA can disrupt the concentrated foci of integrin β3 in motile cells.3. We utilized HUVEC to build up monolayer endothelial cell model, and found that treating with MSA for 12 hours at 5 μM would induce apoptosis of HUVEC, which increase the permeability of HUVEC monolayers to ox-LDL. Mechanism study indicated that MSA could regulate the integrity by increasing calpain activity. In addition, treating with MSA could inhibit ox-LDL uptake of Raw 264.7 and BMDM.In conclusion, MSA could inhibit angiogenesis in vitro, ex vivo and in vivo, by down-regulating integrin β3, disrupting the concentrated foci of integrin β3 and inhibiting the nuclear translocation of NF-κB. Also, MSA could disrupt the integrity of endothelial, which promotes atherosclerosis, but some mechanisms have not been clarified.