Hydrogen sulfide promotes angiogenesis by downregulating miR-640 via the VEGFR2/mTOR pathway

Abstract

We previously found hydrogen sulfide (H2S) to be a new proangiogenic factor. However, the mechanisms underlying the cardiovascular effect of this small gas molecule remain largely unknown. The aim of the present study was to identify the essential microRNAs (miRNAs) involved in the transduction of H2S signals in vascular endothelial cells (ECs). The expression of miR-640 and its signaling elements, vascular endothelial growth factor receptor 2 (VEGFR2), hypoxia inducible factor 1-α (HIF1A), and mammalian target of rapamycin (mTOR), was measured using quantitative PCR and Western blotting. Overexpression and inhibition of miR-640 were performed to clarify their roles in mediating the effect of H2S. In addition, knockdown of VEGFR2, HIF1A, and mTOR was performed using siRNAs, dominant negative mutants, or inhibitors to examine their roles in the transduction of the H2S signals. miR-640 levels decreased in vascular ECs that were treated with H2S, whereas overexpression of miR-640 blunted the proangiogenic effect of H2S. Knockdown of either VEGFR2 or mTOR blunted the downregulation of miR-640 and the proangiogenic effect induced by H2S. In addition, miR-640 bound to the 3'-UTR of HIF1A mRNA and then inhibited the expression of HIF1A. The inhibition could be recovered by treating cells with H2S. Thus we concluded that miR-640 plays a pivotal role in mediating the proangiogenic effect of H2S; H2S acts through downregulation of the expression of miR-640 and increasing the levels of HIF1A through the VEGFR2-mTOR pathway.

Role of Endothelial Dysfunction in Cardiovascular Diseases: The Link Between Inflammation and Hydrogen Sulfide

“…In addition to this, further study has demonstrated that H 2 S specifically disrupts cys1045-cys1024 disulfide bond in vascular endothelial growth factor receptor 2 (VEGFR2) and then stimulates its conformation for angiogenesis (Tao et al, 2013). As a molecular switch, H 2 S is also reported to activate signal transducer and activator of transcription 3 (STAT3) (Kan et al, 2014), mammalian target of rapamycin (mTOR), and the VEGFR2 pathway (Zhou et al, 2016), then the endothelial cell proliferation and angiogenesis are observed. It is noteworthy that FIGURE 3 | Schematic illustration of the underlying mechanisms of H 2 Sinduced angiogenesis.…”

Regulation and role of endogenously produced hydrogen sulfide in angiogenesis

“…Similarly, in rat brain capillary endothelial cells incubation with a H 2 S donor, promoted an increase in HIF-1α and VEGF mRNA and protein levels, and enhanced HIF-1 DNA binding [48]. In cells treated with a H 2 S donor, angiogenic responses were linked to miR-640 down regulation and mediated by a VEGFR2/mTOR/HIF-1α pathway [49]. However, it should be kept in mind that under certain conditions H 2 S donors have been shown to suppress HIF-1 [50].…”

H2S regulates endothelial nitric oxide synthase protein stability by promoting microRNA-455-3p expression

“…Recently, we also reported that the expression of 12 miRNAs in HUVECs were changed after administration of NaHS using an Affymetrix gene chip expression assay. Among these miRNAs, miR-640 is down-regulated and regulates the stability of hypoxia-inducible factor 1 alpha (HIF1A) mRNA14. Considerable evidence has been provided to support the central role of eNOS in regulating endothelial cell functions such as migration24.…”

“…Our previous microarray data has shown that H 2 S could increase the level of miR-455-3p in HUVECs14. Plasma miR-455-3p has been reported to serve as a potential biomarker for abdominal aortic aneurysm15.…”