Thymosin beta4 (Tβ4) has multi-functional roles in angiogenesis and arteriogenesis, but little is known about its mechanism. The Notch signaling pathway is important in regulation of angiogenic behavior of endothelial cells, in addition to vascular endothelial growth factor (VEGF). Whether, Tβ4 regulates angiogenesis through Notch signaling pathway is not clear. In this article, we evaluated the effect of Notch signaling in Tβ4-induced angiogenesis in human umbilical vein endothelial cell (HUVEC). Our results revealed that Tβ4 increased Notch1 and Notch4 expression in a dose and time-dependent manner. The inhibition of Notch1 or Notch4 with siRNA or the Notch receptor inhibitor DAPT significantly prevented Tβ4-induced HUVEC tube formation and lymphocyte transendothelial migration. The inhibition of Notch1 or Notch4 also blocked Tβ4-induced VEGF and HIF-1α expression. VE-cadherin is the major endothelial adhesion molecule in the control of angiogenesis. Tβ4 significantly reduced VE-cadherin expression levels in HUVEC, while the inhibition of Notch signaling prevented Tβ4-induced VE-cadherin down-regulation. The results of this study suggest that Tβ4 induces HUVEC angiogenesis through Notch signaling pathway.

The purpose of this study was to explore the investigative mechanism of salidroside (SAL) on LPS-induced acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). The exosomes from RLE-6TN are extracted and identified by transmission electron microscopy, particle size analysis and protein marker detection, and co-cultured with NR8383 cells. The ALI/ARDS model of SD rats was established by LPS (10 mg/kg) intratracheal instillation. Following a four-hour intratracheal instillation of LPS, 50 μl of RLE-6TN exosomes were injected through the tail vein. After that, SAL and miR-146a antagomir were injected into the tail vein for 72 h, respectively. As the changes of HE stain, body weight and ALI score are observed. The expression of miR-146a, TLR4, NF-kB, IRAK1, TRAF6 and their related proteins were detected by RT-PCR and Western blot, respectively. TNF-α, IL-6, IL-8 and IL-1 β inflammatory factors were detected by ELISA. The expression of miR-146a, NF-kB, IRAK, TRAF6 and related inflammatory factors in LPS-induced NR8383 was significantly higher than that in the control group, while SAL has greatly reduced the expression of TLR4 mediated NF-kB inflammatory pathway and related inflammatory factors. SAL can significantly improve the LPS-induced lung morphological abnormalities, slowed down the rate of weight loss in rats, and reducing the ALI score. The expression trend of NF-kB, IRAK, TRAF6 and related inflammatory factors in rats’ lung tissues was consistent with that in NR8383 cells. SAL has a protective effect on ALI/ARDS caused by sepsis, which is likely to be developed to a potential treatment for the disease. To sum up, this study provides a new theoretical basis for the treatment of ALI/ARDS with SAL.

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An elevated level of BNP in plasma is independently associated with collateral development; patients with good collaterals tend to have a higher BNP level.

Thymosin-β 4 (Tβ4) has been reported to exert a pro-angogenic effect on endothelial cells. However, little is known on the role and underlying mechanisms of Tβ4 on critical limb ischemia (cLI). The present study aimed therefore to investigate the mechanisms and pro-angiogenic effects of Tβ4 in cLI mice. Tβ4 overexpression lentiviral vector was first transfected into HUVEC and CLI mice model, and inhibitors of Notch pathway (dAPT) and NF-κB pathway (BMS) were also applied to HUVEC and CLI mice. Subsequently, MTT, tube formation and wound healing assays were used to determine the cell viability, angiogenesis and migratory ablity of HUVEC, respectively. Western blotting, reverse transcription, quantitative PCR, immunofluorescence and immunohistochemistry were used to detect the expression of the angiogenesis-related factors angiopoietin-2 (Ang2), TEK receptor tyrosine kinase 2 (tie2), vascular endothelial growth factor A (VEGFA), CD31 and α-smooth muscle actin (α-SMA) and the Notch/NF-κB pathways-related factors NOTcH1 intracellular domain (N1Icd), Notch receptor 3 (Notch3), NF-κB and p65 in HUVEC or CLI mice muscle tissues. The results demonstrated that Tβ4 not only enhanced the cell viability, angiogenesis and migratory ability of HUVEC but also promoted the expression of Ang2, tie2, VEGFA, N1ICD, Notch3, NF-κB, and phosphorylated (p)-p65 in HUVEC. In addition, Tβ4 promoted the expression of cd31, α-SMA Ang2, tie2, VEGFA, N1ICD and p-p65 in CLI mice muscle tissues. Treatment with dAPT and BMS had opposite effects of Tβ4, whereas Tβ4 reversed the effect of dAPT and BMS. The findings from the present study suggested that Tβ4 may promote angiogenesis in cLI mice via regulation of Notch/NF-κB pathways.