The distal airways of the lung and bone marrow are innervated by the vagus nerve. Vagal α7nAChR signaling plays a key role in regulating lung infection and inflammation; however, whether this pathway regulates α7nAChR+Sca1+ cells during lung injury repair remains unknown. We hypothesized that vagal α7nAChR signaling controls α7nAChR+Sca1+ cells, which contribute to the resolution of lung injury. Pneumonia was induced by intratracheal challenge with E. coli. The bone marrow mononuclear cells (BM-MNCs) were isolated from the bone marrow of pneumonia mice for immunofluorescence. The bone marrow, blood, BAL, and lung cells were isolated for flow cytometric analysis by labeling with anti-Sca1, VE-cadherin, p-Akt1, or Flk1 antibodies. Immunofluorescence was also used to examine the coexpression of α7nAChR, VE-cadherin, and p-Akt1. Sham, vagotomized, α7nAChR knockout, and Akt1 knockout mice were infected with E. coli to study the regulatory role of vagal α7nAChR signaling and Akt1 in Sca1+ cells. During pneumonia, BM-MNCs were enriched with α7nAChR+Sca1+ cells, and this cell population proliferated. Transplantation of pneumonia BM-MNCs could mitigate lung injury and increase engraftment in recipient pneumonia lungs. Activation of α7nAChR by its agonist could boost α7nAChR+Sca1+ cells in the bone marrow, peripheral blood, and bronchoalveolar lavage (BAL) in pneumonia. Immunofluorescence revealed that α7nAChR, VE-cadherin, and p-Akt1 were coexpressed in the bone marrow cells. Vagotomy could reduce α7nAChR+VE-cadherin+ and VE-cadherin+p-Akt1+ cells in the bone marrow in pneumonia. Knockout of α7nAChR reduced VE-cadherin+ cells and p-Akt1+ cells in the bone marrow. Deletion of Akt1 reduced Sca1+ cells in the bone marrow and BAL. More importantly, 91.3 ± 4.9% bone marrow and 77.8 ± 4.9% lung α7nAChR+Sca1+VE-cadherin+ cells expressed Flk1, which is a key marker of endothelial progenitor cells (EPCs). Vagotomy reduced α7nAChR+Sca1+VE-cadherin+p-Akt1+ cells in the bone marrow and lung from pneumonia mice. Treatment with cultured EPCs reduced ELW compared to PBS treatment in E. coli pneumonia mice at 48 h. The ELW was further reduced by treatment with EPCs combining with α7nAChR agonist-PHA568487 compared to EPC treatments only. Vagal α7nAChR signaling regulates α7nAChR+Sca1+VE-cadherin+ EPCs via phosphorylation of Akt1 during lung injury repair in pneumonia.

中文翻译：

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迷走神经α7nAChR信号调节肺损伤修复过程中的α7nAChR+ Sca1 +细胞。

迷走神经支配肺和骨髓的远端气道。迷走神经α7nAChR信号传导在调节肺部感染和炎症中起关键作用。然而，该途径是否在肺损伤修复过程中调节α7nAChR+ Sca1 +细胞尚不清楚。我们假设迷走神经α7nAChR信号控制α7nAChR+ Sca1 +细胞，有助于解决肺损伤。大肠杆菌经气管内攻击诱发肺炎。从肺炎小鼠的骨髓中分离出骨髓单核细胞（BM-MNCs）用于免疫荧光。通过用抗Sca1，VE-钙粘着蛋白，p-Akt1或Flk1抗体标记，分离出骨髓，血液，BAL和肺细胞用于流式细胞术分析。免疫荧光法还用于检查α7nAChR，VE-钙粘着蛋白和p-Akt1的共表达。伪装成虚假的伪装，用大肠杆菌感染α7nAChR基因敲除小鼠和Akt1基因敲除小鼠，以研究迷走性α7nAChR信号传导和Akt1在Sca1 +细胞中的调节作用。在肺炎期间，BM-MNCs富含α7nAChR+ Sca1 +细胞，并且该细胞群增殖。肺炎BM-MNCs的移植可以减轻肺损伤并增加受体肺炎肺的植入。激动剂激活α7nAChR可以增强肺炎，骨髓，外周血和支气管肺泡灌洗（BAL）中的α7nAChR+ Sca1 +细胞。免疫荧光显示，α7nAChR，VE-钙黏着蛋白和p-Akt1在骨髓细胞中共表达。迷走神经切断术可以减少肺炎患者骨髓中的α7nAChR+ VE-cadherin +和VE-cadherin + p-Akt1 +细胞。敲除α7nAChR可减少骨髓中的VE-钙粘蛋白+细胞和p-Akt1 +细胞。Akt1的删除减少了骨髓和BAL中的Sca1 +细胞。更重要的是，91.3±4.9％的骨髓和77.8±4.9％的肺α7nAChR+ Sca1 + VE-钙粘蛋白+细胞表达了Flk1，这是内皮祖细胞（EPC）的关键标志。迷走神经切断术减少了肺炎小鼠骨髓和肺中的α7nAChR+ Sca1 + VE-钙黏着蛋白+ p-Akt1 +细胞。与PBS处理48小时的大肠杆菌肺炎小鼠相比，用培养的EPC处理可降低ELW。与仅采用EPC处理相比，通过EPC与α7nAChR激动剂-PHA568487联合使用可进一步降低ELW。迷走神经α7nAChR信号传导在肺炎肺损伤修复过程中通过Akt1的磷酸化调节α7nAChR+ Sca1 + VE-钙粘蛋白+ EPC。这是内皮祖细胞（EPC）的关键标记。迷走神经切断术减少了肺炎小鼠骨髓和肺中的α7nAChR+ Sca1 + VE-钙黏着蛋白+ p-Akt1 +细胞。与PBS处理48小时的大肠杆菌肺炎小鼠相比，用培养的EPC处理可降低ELW。与仅采用EPC处理相比，通过EPC与α7nAChR激动剂-PHA568487联合使用可进一步降低ELW。迷走神经α7nAChR信号传导在肺炎肺损伤修复过程中通过Akt1的磷酸化调节α7nAChR+ Sca1 + VE-钙粘蛋白+ EPC。这是内皮祖细胞（EPC）的关键标记。迷走神经切断术减少了肺炎小鼠骨髓和肺中的α7nAChR+ Sca1 + VE-钙黏着蛋白+ p-Akt1 +细胞。与PBS处理48小时的大肠杆菌肺炎小鼠相比，用培养的EPC处理可降低ELW。与仅采用EPC处理相比，通过EPC与α7nAChR激动剂-PHA568487联合使用可进一步降低ELW。迷走神经α7nAChR信号传导在肺炎肺损伤修复过程中通过Akt1的磷酸化调节α7nAChR+ Sca1 + VE-钙粘蛋白+ EPC。与仅采用EPC处理相比，通过EPC与α7nAChR激动剂-PHA568487联合使用可进一步降低ELW。迷走神经α7nAChR信号传导在肺炎肺损伤修复过程中通过Akt1的磷酸化调节α7nAChR+ Sca1 + VE-钙粘蛋白+ EPC。与仅采用EPC处理相比，通过EPC与α7nAChR激动剂-PHA568487联合使用可进一步降低ELW。迷走神经α7nAChR信号传导在肺炎肺损伤修复过程中通过Akt1的磷酸化调节α7nAChR+ Sca1 + VE-钙粘蛋白+ EPC。