Scholarlink

Aim <p>The important role of phosphodiesterase 4B (PDE4B) inhibition on lipopolysaccharide (LPS)-induced ALI has been reported. However, the corresponding mechanisms remain unclear. In the present study, the relationship between PDE4B and phosphorylation of p65 (Ser468) in LPS-induced injury by in vivo and in vitro models was investigated.</p> Methods and results <p><i>pde4b</i><sup>+/+</sup> mice, inflammation was significantly up-regulated after LPS stimulation, including the highest number of immune cells, especially neutrophils, and the level of pro-inflammatory cytokines measured by ELISA, while all those were blunted in <i>pde4b</i><sup>−/−</sup> mice. Moreover, <i>pde4b</i><sup>−/−</sup> mice improved the expression of PKA in lung tissues and down-regulated the IKKα/β-NF-κB p65 signaling determined by western blotting. In vitro experiments in MH-S cells revealed that siRNA-mediated specific silence of PDE4B expression resulted in a decrease of inflammatory markers and phosphorylation of p65 at Ser468 after LPS treatment, but overexpressing PDE4B increased the inflammation and phosphorylation of p65 at Ser468. In MH-S cells, luciferase analysis indicated that PDE4B acts as a positive regulator of p65 in inflammation. PKA inhibitor (H-89) increased pP65 and PDE4B expression, while PKA activator (6-BZ-cAMP) showed the opposite effect in macrophages. More importantly, the proteasome-mediated degradation of cAMP effector was negatively correlated with the phosphorylation of p65 (Ser468) and PDE4B expression in MH-S cells.</p> Conclusions <p>PDE4B plays a critical role in orchestrating LPS-induced acute lung inflammation by cAMP/PKA axis-mediated phosphorylation of p65.</p> Graphical Abstract <p>Schematic model of PDE4B in the LPS-induced inflammatory signaling process. In <i>pde4b</i><sup>+<i>/</i>+</sup> mice, LPS binding with TLR4 receptor and down-regulates cAMP/PKA thus modulates NF-κB/pP65 phosphorylation at Ser468 site, leading to the inflammatory response: release of TNF-α, IL-6, and IL-1β; neutrophil infiltration. PDE4B knockout can decrease cAMP/PKA and phosphorylation of IKK and p65 (Ser468), down-regulate the cells recruitment and the release of inflammatory cytokines in ALI mouse model and macrophages.</p> <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

PDE4B Modulates Phosphorylation of p65 (Ser468) via cAMP/PKA in Acute Lung Injury

  • 期刊论文

  • 发表日期：

    2025年2月16日

查看全文
  • Rana Dhar,
  • Yajun Li,
  • Zhengqiang Hu,
  • Shunde Song,
  • Zhewen Zhang,
  • Jie Ji,
  • Xuefeng Wang,
  • Xuyang Zheng,
  • Zigang Li,
  • Chunguang Yan,
  • Huifang Tang

摘要

Aim

The important role of phosphodiesterase 4B (PDE4B) inhibition on lipopolysaccharide (LPS)-induced ALI has been reported. However, the corresponding mechanisms remain unclear. In the present study, the relationship between PDE4B and phosphorylation of p65 (Ser468) in LPS-induced injury by in vivo and in vitro models was investigated.

Methods and results

pde4b+/+ mice, inflammation was significantly up-regulated after LPS stimulation, including the highest number of immune cells, especially neutrophils, and the level of pro-inflammatory cytokines measured by ELISA, while all those were blunted in pde4b−/− mice. Moreover, pde4b−/− mice improved the expression of PKA in lung tissues and down-regulated the IKKα/β-NF-κB p65 signaling determined by western blotting. In vitro experiments in MH-S cells revealed that siRNA-mediated specific silence of PDE4B expression resulted in a decrease of inflammatory markers and phosphorylation of p65 at Ser468 after LPS treatment, but overexpressing PDE4B increased the inflammation and phosphorylation of p65 at Ser468. In MH-S cells, luciferase analysis indicated that PDE4B acts as a positive regulator of p65 in inflammation. PKA inhibitor (H-89) increased pP65 and PDE4B expression, while PKA activator (6-BZ-cAMP) showed the opposite effect in macrophages. More importantly, the proteasome-mediated degradation of cAMP effector was negatively correlated with the phosphorylation of p65 (Ser468) and PDE4B expression in MH-S cells.

Conclusions

PDE4B plays a critical role in orchestrating LPS-induced acute lung inflammation by cAMP/PKA axis-mediated phosphorylation of p65.

Graphical Abstract

Schematic model of PDE4B in the LPS-induced inflammatory signaling process. In pde4b+/+ mice, LPS binding with TLR4 receptor and down-regulates cAMP/PKA thus modulates NF-κB/pP65 phosphorylation at Ser468 site, leading to the inflammatory response: release of TNF-α, IL-6, and IL-1β; neutrophil infiltration. PDE4B knockout can decrease cAMP/PKA and phosphorylation of IKK and p65 (Ser468), down-regulate the cells recruitment and the release of inflammatory cytokines in ALI mouse model and macrophages.