背景:全身性炎症和程序性细胞死亡之间的相互作用有助于急性肺损伤(ALI)的发病机理。cAMP调节的转录共激活因子1(CRTC1)参与了肺系统的正常功能,但其在ALI中的作用尚不清楚。
结果:我们产生了Crtc1敲除(KO;Crtc1-/-)小鼠系。通过盲肠结扎穿孔(CLP)24h建立脓毒症诱导的ALI。数据显示Ctrc1KO显著改善CLP诱导的ALI表型,包括改善肺结构破坏,肺血管通透性降低,促炎细胞因子和趋化因子的水平降低,与野生型小鼠相比。始终如一,在脂多糖(LPS)处理的RAW264.7细胞中,Crtc1敲低显著抑制炎症效应子的表达,包括TNF-α,IL-1β,IL-6和CXCL1,而它们的表达通过Crtc1过表达显着增强。此外,小鼠中的Crtc1KO及其在RAW264.7细胞中的敲除均显着降低了TUNEL阳性细胞和促凋亡蛋白的表达。相比之下,Crtc1过表达导致促凋亡蛋白和LPS诱导的TUNEL阳性细胞增加。机械上,我们发现,Akt的磷酸化被Crtc1敲除或敲除显著增强,但被Crtc1过表达抑制。Triciribine的管理,Akt抑制剂,显著阻断Crtc1敲低对LPS诱导的RAW264.7细胞炎症和细胞死亡的保护作用。
结论:我们的研究表明,CRTC1有助于脓毒症诱导的ALI的炎症和细胞凋亡的病理过程,并提供了对CRTC1在肺中的分子功能的机制见解。靶向CRTC1将是临床上治疗脓毒症诱导的ALI的有希望的策略。
BACKGROUND: Interplay between systemic inflammation and programmed cell death contributes to the pathogenesis of acute lung injury (ALI). cAMP-regulated transcriptional coactivator 1 (
CRTC1) has been involved in the normal function of the pulmonary system, but its role in ALI remains unclear.
RESULTS: We generated a
Crtc1 knockout (KO;
Crtc1-/-) mouse line. Sepsis-induced ALI was established by cecal ligation and puncture (CLP) for 24 h. The data showed that Ctrc1 KO substantially ameliorated CLP-induced ALI phenotypes, including improved lung structure destruction, reduced pulmonary vascular permeability, diminished levels of proinflammatory cytokines and chemokines, compared with the wildtype mice. Consistently, in lipopolysaccharide (LPS)-treated RAW264.7 cells, Crtc1 knockdown significantly inhibited the expression of inflammatory effectors, including TNF-α, IL-1β, IL-6 and CXCL1, whereas their expressions were significantly enhanced by Crtc1 overexpression. Moreover, both Crtc1 KO in mice and its knockdown in RAW264.7 cells dramatically reduced TUNEL-positive cells and the expression of pro-apoptotic proteins. In contrast, Crtc1 overexpression led to an increase in the pro-apoptotic proteins and LPS-induced TUNEL-positive cells. Mechanically, we found that the phosphorylation of Akt was significantly enhanced by Crtc1 knockout or knockdown, but suppressed by
Crtc1 overexpression. Administration of Triciribine, an Akt inhibitor, substantially blocked the protection of Crtc1 knockdown on LPS-induced inflammation and cell death in RAW264.7 cells.
CONCLUSIONS: Our study demonstrates that
CRTC1 contribute to the pathological processes of inflammation and apoptosis in sepsis-induced ALI, and provides mechanistic insights into the molecular function of CRTC1 in the lung. Targeting
CRTC1 would be a promising strategy to treat sepsis-induced ALI in clinic.