Circ-100290 Regulates Autophagy-Mediated Angiogenesis of Human Umbilical Vein Endothelial Cells Induced by Conditioned Medium of Human Amniotic Mesenchymal Stem Cells.

Conditioned medium (CM) from human amnion-derived mesenchymal stem cells (hAMSCs) exhibits excellent pro-angiogenic capacity, and circ-100290 participates in this process. Autophagy is involved in the relevant mechanisms of angiogenesis, but it is unclear whether autophagy is related to the pro-angiogenesis effect of hAMSCs. This research sought to determine whether autophagy involved in the process of pro-angiogenesis induced by hAMSCs might be regulated by circ-100290. Upon treatment with CM from hAMSC or 3-methyladenine (3-MA), autophagosomes in human umbilical vein endothelial cells (HUVECs) were observed by transmission electron microscopy. HUVECs' angiogenic ability was evaluated by in vitro assays (transwell, wound healing, tube formation) and an in vivo Matrigel plug assay. Specific small interfering RNAs (siRNA) or inhibitors were used to regulate circ-100290 expression. Additionally, western blot and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) were used to evaluate expression of the following indicators: Beclin-1, LC3-II, matrix metalloproteinase 2 (MMP2), MMP9, vascular endothelial growth factor (VEGF)-A, and endothelial nitric oxide synthase (eNOS). Incubation with hAMSC-CM increased autophagy, angiogenesis and the expressions of VEGF-A and eNOS in HUVECs, all of which were inhibited by 3-MA. Knocking down circ-100290 in hAMSC-CM-treated HUVECs reduced Beclin-1 expression and inhibited autophagy. This resulted in lower angiogenesis in the Matrigel plug assay showing that reduced angiogenesis occurred after circ-100290 silencing in hAMSC-CM-treated HUVECs. Circ-100290 promotes autophagy-mediated angiogenesis in hAMSC-CM-treated HUVECs.

Yang L ，Yan H ，Liang Y ，Sun D ，Lu S ，Tang Z ，Ma M ，Shen M ... -  《-》

Circ-100290 Positively Regulates Angiogenesis Induced by Conditioned Medium of Human Amnion-Derived Mesenchymal Stem Cells Through miR-449a/eNOS and miR-449a/VEGFA Axes.

The powerful pro-angiogenic capacity of human amnion-derived mesenchymal stem cells (hAMSCs) could be a valuable therapeutic angiogenesis strategy for bone regeneration. However, the molecular mechanisms underlying this process remain largely unknown. Herein, we report upregulated expression of circular RNA 100290 (circ-100290) and an enhanced angiogenic phenotype of human umbilical vein endothelial cells (HUVECs) incubated with conditioned medium from hAMSCs (hAMSC-CM), whereas downregulation of circ-100290 reversed the pro-angiogenic capacity of HUVECs induced by hAMSC-CM. Circ-100290/microRNA 449a (miR-449a)/endothelial nitric oxide synthase (eNOS) and circ-100290/miR-449a/vascular endothelial growth factor A (VEGFA) axes were predicted by a bioinformatics method and subsequently verified by luciferase reporter assays in vitro. Gain- or loss-of-function assays were then performed using small interfering RNAs (siRNAs) targeting circ-100290, or a plasmid overexpressing circ-100290. As expected, downregulation of circ-100290 in HUVECs led to weakened tube formation and migration of HUVECs following hAMSC-CM treatment, along with decreased expression of eNOS and VEGFA. In contrast, upregulation of circ-100290 led to enhanced tube formation and migration of HUVECs following hAMSC-CM treatment, along with increased expression of eNOS and VEGFA. Furthermore, a miR-449a inhibitor could largely rescue the effect of circ-100290 silencing on HUVECs, whereas a miR-449a mimic could significantly rescue the effect of overexpressing circ-100290 on HUVECs. Functional assays using eNOS or VEGF receptor inhibitors indicated eNOS and VEGFA may be important targets of miR-449a. Finally, a Matrigel plug assay revealed weakened angiogenesis when circ-100290 was silenced in HUVECs, but enhanced angiogenesis when circ-100290 was overexpressed in vivo. Our results suggest that circ-100290 might function via miR-449a/eNOS and miR-449a/VEGFA axes in the pro-angiogenic role of hAMSC-CM on HUVECs.

Tang Z ，Wu X ，Hu L ，Xiao Y ，Tan J ，Zuo S ，Shen M ，Yuan X ... -  《International Journal of Biological Sciences》

Circular RNA-ABCB10 promotes angiogenesis induced by conditioned medium from human amnion-derived mesenchymal stem cells via the microRNA-29b-3p/vascular endothelial growth factor A axis.

The powerful ability of human amnion-derived mesenchymal stem cells (hAMSCs) to promote angiogenesis suggests that they may facilitate angiogenesis-associated therapeutic strategies. However, the molecular mechanisms underlying hAMSC-induced angiogenesis remain largely unknown. The present study results suggested that enhanced migration and tube formation in human umbilical vein endothelial cells (HUVECs) was induced by conditioned medium from hAMSCs (hAMSC-CM). In addition, culture with this conditioned medium resulted in the increased expression of circular RNA ATP binding cassette subfamily B member 10 (circ-ABCB10) and vascular endothelial growth factor A (VEGFA). In the present study genes related to thecirc-ABCB10/microRNA (miR)-29b-3p/VEGFA pathway were predicted using bioinformatics software, and further investigated using in vitro luciferase reporter assays. Loss-of-function assays were performed using small interfering RNAs (siRNAs). The results suggested that siRNA-silencing of circ-ABCB10 in HUVECs weakened migration and tube formation of HUVECs following hAMSC-CM treatment and reduced the levels of VEGFA expression. Treatment with an miR-29b-3p inhibitor could largely rescue these effects in HUVECs, following circ-ABCB10 silencing. The present study results suggest that the circ-ABCB10/miR-29b-3p/VEGFA pathway may be involved in the pro-angiogenic role of hAMSC-CM in HUVECs.

Tang Z ，Tan J ，Yuan X ，Zhou Q ，Yuan Z ，Chen N ，Shen M ... -  《-》

Conditioned medium derived from FGF-2-modified GMSCs enhances migration and angiogenesis of human umbilical vein endothelial cells.

Jin S ，Yang C ，Huang J ，Liu L ，Zhang Y ，Li S ，Zhang L ，Sun Q ，Yang P ... -  《Stem Cell Research & Therapy》

LncRNA H19 Knockdown in Human Amniotic Mesenchymal Stem Cells Suppresses Angiogenesis by Associating with EZH2 and Activating Vasohibin-1.

Yuan Z ，Bian Y ，Ma X ，Tang Z ，Chen N ，Shen M ... -  《-》