BACKGROUND Telocytes (TCs) are newly identified interstitial cells that participate in tissue protection and repair. The present study investigated the mechanisms underlying the protective effect of TCs in a mouse model of respiratory distress. METHODS The mouse model of acute respiratory distress syndrome (ARDS) was established by intratracheal instillation of lipopolysaccharide (LPS). After instillation of TCs culture medium, lung injury was assessed, and angiogenesis markers, including CD31 and endothelial nitric oxide synthase (eNOS), were detected by immunofluorescence. Bioinformatics analysis was used to screen significantly differentially expressed microRNAs (miRNAs) in cultured TCs stimulated with LPS, and the regulation of downstream angiogenesis genes by these miRNAs was analysed and verified. PI3K subunits and pathways were evaluated by using a PI3K p110α inhibitor to study the involved mechanisms. RESULTS In ARDS mice, instillation of TCs culture medium ameliorated LPS-induced inflammation and lung injury and increased the protein levels of CD31 and eNOS in the injured lungs. A total of 7 miRNAs and 1899 mRNAs were differentially regulated in TCs stimulated with LPS. Functional prediction analysis showed that the differentially expressed mRNAs were enriched in angiogenesis-related processes, which were highly correlated with miR-21a-3p. Culture medium from TCs with miR-21a-3p inhibition failed to promote angiogenesis in mouse models of LPS-induced ARDS. In cultured TCs, LPS stimulation upregulated the expression of miR-21a-3p, which further targeted the transcription factor E2F8 and decreased Notch2 protein expression. TCs culture medium enhanced hemangioendothelioma endothelial cells (EOMA cells) proliferation, which was blocked by the miR-21a-3p inhibitor. The PI3K p110α inhibitor decreased vascular endothelial growth factor levels in LPS-stimulated TCs and reversed the enhancing effect of TCs culture medium on EOMA cells proliferation. CONCLUSIONS TCs exerted protective effects under inflammatory conditions by promoting angiogenesis via miR-21a-3p. The PI3K p110α subunit and transcriptional factor E2F8 could be involved in this process.

中文翻译：

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microRNA-21a-3p对LPS诱导的小鼠ARDS介导的PI3K（p110α）/ AKT / mTOR介导的端粒细胞血管生成的促进作用。

背景技术卵母细胞（TC）是新近鉴定的参与组织保护和修复的间质细胞。本研究调查了TCs在呼吸窘迫小鼠模型中的保护作用的潜在机制。方法通过气管内滴注脂多糖（LPS）建立急性呼吸窘迫综合征（ARDS）小鼠模型。滴注TCs培养基后，评估肺损伤，并通过免疫荧光检测血管生成标记，包括CD31和内皮型一氧化氮合酶（eNOS）。生物信息学分析用于筛选LPS刺激的培养TC中显着差异表达的microRNA（miRNA），并分析和验证了这些miRNA对下游血管生成基因的调控。通过使用PI3Kp110α抑制剂评估PI3K亚基和途径，以研究所涉及的机制。结果在ARDS小鼠中，滴注TCs培养基可减轻LPS诱导的炎症和肺损伤，并增加受伤肺中CD31和eNOS的蛋白质水平。在LPS刺激的TC中，总共有7个miRNA和1899个mRNA被差异调节。功能预测分析表明差异表达的mRNAs在与miR-21a-3p高度相关的血管生成相关过程中富集。来自具有miR-21a-3p抑制作用的TCs的培养基未能在LPS诱导的ARDS小鼠模型中促进血管生成。在培养的TC中，LPS刺激上调了miR-21a-3p的表达，后者进一步靶向了转录因子E2F8，并降低了Notch2蛋白的表达。TCs培养基增强了血管内皮细胞瘤内皮细胞（EOMA细胞）的增殖，这被miR-21a-3p抑制剂所阻断。PI3Kp110α抑制剂可降低LPS刺激的TCs的血管内皮生长因子水平，并逆转TCs培养基对EOMA细胞增殖的增强作用。结论TCs在炎症条件下通过miR-21a-3p促进血管生成而发挥保护作用。PI3Kp110α亚基和转录因子E2F8可能参与此过程。结论TCs在炎症条件下通过miR-21a-3p促进血管生成而发挥保护作用。PI3Kp110α亚基和转录因子E2F8可能参与此过程。结论TCs在炎症条件下通过miR-21a-3p促进血管生成而发挥保护作用。PI3Kp110α亚基和转录因子E2F8可能参与此过程。