Kallistatin attenuates endothelial senescence by modulating Let‐7g‐mediated miR‐34a‐SIRT1‐eNOS pathway

Abstract

Kallistatin, a plasma protein, protects against vascular and organ injury. This study is aimed to investigate the role and mechanism of kallistatin in endothelial senescence. Kallistatin inhibited H2O2‐induced senescence in human endothelial cells, as indicated by reduced senescence‐associated‐β‐galactosidase activity, p16INK 4a and plasminogen activator inhibitor‐1 expression, and elevated telomerase activity. Kallistatin blocked H2O2‐induced superoxide formation, NADPH oxidase levels and VCAM‐1, ICAM‐1, IL‐6 and miR‐34a synthesis. Kallistatin reversed H2O2‐mediated inhibition of endothelial nitric oxide synthase (eNOS), SIRT1, catalase and superoxide dismutase (SOD)‐2 expression, and kallistatin alone stimulated the synthesis of these antioxidant enzymes. Moreover, kallistatin's anti‐senescence and anti‐oxidant effects were attributed to SIRT1‐mediated eNOS pathway. Kallistatin, via interaction with tyrosine kinase, up‐regulated Let‐7g, whereas Let‐7g inhibitor abolished kallistatin's effects on miR‐34a and SIRT1/eNOS synthesis, leading to inhibition of senescence, oxidative stress and inflammation. Furthermore, lung endothelial cells isolated from endothelium‐specific kallistatin knockout mice displayed marked reduction in mouse kallistatin levels. Kallistatin deficiency in mouse endothelial cells exacerbated senescence, oxidative stress and inflammation compared to wild‐type mouse endothelial cells, and H2O2 treatment further magnified these effects. Kallistatin deficiency caused marked reduction in Let‐7g, SIRT1, eNOS, catalase and SOD‐1 mRNA levels, and elevated miR‐34a synthesis in mouse endothelial cells. These findings indicate that endogenous kallistatin through novel mechanisms protects against endothelial senescence by modulating Let‐7g‐mediated miR‐34a‐SIRT1‐eNOS pathway.

Exosomes derived from GDNF-modified human adipose mesenchymal stem cells ameliorate peritubular capillary loss in tubulointerstitial fibrosis by activating the SIRT1/eNOS signaling pathway

“…Furthermore, there was a strong correlation between SIRT1 expression level in the kidney and a decrease in the total perfused peritubular cross-sectional area and PTC number ( Figure 5 C ), suggesting that SIRT1 activation facilitates PTC construction. Since eNOS has been reported to be a downstream target of SIRT1 37 , we hypothesized that the SIRT1/eNOS axis mediates the angiogenic response induced by GDNF-AMSC-exos. Western blotting revealed that treatment with GDNF-AMSC-exos significantly increased eNOS phosphorylation ( Figure 5 D ).…”

Protective Role of Endogenous Kallistatin in Vascular Injury and Senescence by Inhibiting Oxidative Stress and Inflammation

“…As a deacetylase, SIRT1 stimulates antioxidant enzymes including eNOS, catalase, and superoxide dismutase (SOD), and eNOS through NO production stimulates SIRT1 enzymatic activity and inhibits NADPH oxidase activity [58, 59], leading to the attenuation of oxidative stress. Similarly, kallistatin exerts salutary effects in the setting of H 2 O 2 -induced endothelial senescence, oxidative stress, and inflammation, as indicated by reduced p16 INK4a , PAI-1, and miR-34a synthesis, NADPH oxidase activity/expression, vascular cell adhesion molecule- (VCAM-) 1 and intercellular adhesion molecule- (ICAM-) 1 expression, and increased telomerase activity in endothelial cells [60]. Moreover, kallistatin via upregulating the endoprotective miRNA Let-7g coordinates Let-7g-modulated miR-34a-SIRT1-eNOS pathway and achieves antisenescent, antioxidant, and anti-inflammatory actions in endothelial cells [60].…”

“…Similarly, kallistatin exerts salutary effects in the setting of H 2 O 2 -induced endothelial senescence, oxidative stress, and inflammation, as indicated by reduced p16 INK4a , PAI-1, and miR-34a synthesis, NADPH oxidase activity/expression, vascular cell adhesion molecule- (VCAM-) 1 and intercellular adhesion molecule- (ICAM-) 1 expression, and increased telomerase activity in endothelial cells [60]. Moreover, kallistatin via upregulating the endoprotective miRNA Let-7g coordinates Let-7g-modulated miR-34a-SIRT1-eNOS pathway and achieves antisenescent, antioxidant, and anti-inflammatory actions in endothelial cells [60]. Activation of SIRT1-eNOS signaling results in increased catalase and NO levels, thus suppressing oxidative vascular damage [60].…”

“…Moreover, kallistatin via upregulating the endoprotective miRNA Let-7g coordinates Let-7g-modulated miR-34a-SIRT1-eNOS pathway and achieves antisenescent, antioxidant, and anti-inflammatory actions in endothelial cells [60]. Activation of SIRT1-eNOS signaling results in increased catalase and NO levels, thus suppressing oxidative vascular damage [60]. These combined studies reveal the mechanisms of kallistatin in protection against vascular injury by reducing cellular senescence in EPCs and endothelial cells.…”

Sepsis diagnosis and monitoring – procalcitonin as standard, but what next?

“…The heparin-binding site of kallistatin blocks high mobility group box 1 (HMGB1)-induced inflammatory gene expression in endothelial cells [17]. Kallistatin increases endoprotective miRNA Let-7g synthesis and through Let-7g induction stimulates eNOS, causing inhibition of oxidative stress and inflammation in endothelial cells ( Figure 1) [18]. Possibly kallistatin through active site interaction with tyrosine kinase stimulates Let-7g synthesis.…”