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Endothelial cells injury and pro-inflammation cytokines release are the initial steps of hyperhomocysteinemia (HHcy)-associated vascular inflammation. Pyroptosis is a newly identified pro-inflammation form of programmed cell death, causing cell lysis and IL-1β release, and characterized by the caspases-induced cleavage of its effector molecule gasdermins (GSDMs). However, the effect of homocysteine (Hcy) on endothelial cells pyroptosis and the underlying mechanisms have not been fully defined. We have previously reported that Hcy induces vascular endothelial inflammation accompanied by the increase of high mobility group box-1 protein (HMGB1) and lysosomal cysteine protease cathepsin V in endothelial cells, and other studies have shown that HMGB1 or cathepsins are involved in activation of NLRP3 inflammasome and caspase-1. Here, we investigated the role of HMGB1 and cathepsin V in the process of Hcy-induced pyroptosis. We observed an increase in plasma IL-1β levels in HHcy patients and mice models, cathepsin V inhibitor reduced the plasma IL-1β levels and cleavage of GSDMD full-length into GSDMD N-terminal in the thoracic aorta of hyperhomocysteinemia mice. Using cultured HUVECs, we observed that Hcy promoted GSDMD N-terminal expression, silencing GSDMD or HMGB1 rescued Hcy-induced pyroptosis. HMGB1 also increased GSDMD N-terminal expression, and silencing cathepsin V reversed HMGB1-induced pyroptosis. HMGB1 could increase lysosome permeability, and silencing cathepsin V attenuated HMGB1-induced activation of caspase-1. In conclusion, this study has delineated a novel mechanism that HMGB1 mediated Hcy-induced endothelial cells pyroptosis partly via cathepsin V-dependent pathway. • Hcy induced GSDMD-mediated endothelial cells pyroptosis. • HMGB1 mediated Hcy-induced pyroptosis. • Cathepsin V was involved in Hcy or HMGB1-induced pyroptosis. [ABSTRACT FROM AUTHOR]

Angiogenesis is the process by which new blood vessels form from preexisting vessels and regulates the processes of embryonic development, wound healing and tumorigenesis. HMGA2 is involved in the occurrence of several cancers, but its biological role and the exact downstream genes involved in vascular development and sprouting angiogenesis remain largely unknown. Here, we first found that HMGA2 knockdown in zebrafish embryos resulted in defects of central artery formation. RNA sequencing revealed that IGFBP2 was significantly downregulated by interference with HMGA2, and IGFBP2 overexpression reversed the inhibition of brain vascular development caused by HMGA2 deficiency. In vitro , we further found that HMGA2 knockdown blocked the migration, tube formation and branching of HUVECs. Similarly, IGFBP2 protein overexpression attenuated the impairments induced by HMGA2 deficiency. Moreover, the promotion of angiogenesis by HMGA2 overexpression was verified in a Matrigel plug assay. We next found that HMGA2 bound directly to a region in the IGFBP2 promoter and positively regulated IGFBP2 expression. Interestingly, the mRNA expression levels of HMGA2 and IGFBP2 were increased significantly in the peripheral blood of hemangioma patients, indicating that overexpression of HMGA2 and IGFBP2 results in vessel formation, consistent with the results of the in vivo and in vitro experiments. In summary, our findings demonstrate that HMGA2 promotes central artery formation by modulating angiogenesis via IGFBP2 induction. • Our findings demonstrates that HMGA2 promotes central arteries formation in zebrafish. • HMGA2 induces vascular development through modulation of IGFBP2 whatever in vivo or in vitro. • The mRNA expressions of HMGA2 and IGFBP2 increased significantly in peripheral blood of Hemangioma patients. • HMGA2-IGFBP2 are promising candidates towards therapeutical vascularization in vascular diseases like Hemangioma. [ABSTRACT FROM AUTHOR]

We have investigated the antioxidant effect of adrenomedullin (AM) on endothelial function in the Dahl salt-sensitive (DS) rat hypertension model. Dahl salt-resistant (DR) and DS rats were fed an 8% NaCl diet. In addition, the DS rats were subcutaneously infused with either saline or recombinant human AM for 4 weeks. Although systolic blood pressures measured weekly in AM- and saline-infused rats did not significantly differ, aortic O2᛫− levels were significantly (P <0.01) higher in the latter. Likewise, both endothelial nitric oxide synthase (eNOS) mRNA and protein were significantly higher in saline-infused DS rats. Infusion of AM reduced both O2− and eNOS expression to levels comparable to those seen in DR rats. AM infusion also upregulated the gene expression of guanosine-5′-triphosphate cyclohydrolase I and downregulated the expression of p22phox, suggesting that AM increased the NOS coupling and bioavailability of NO. AM possesses significant antioxidant properties that improve endothelial function. [Copyright &y& Elsevier]