School of Clinical Medicine, Guizhou Medical University, 550004 Guiyang, China.
School of Clinical Medicine, Guizhou Medical University, 550004 Guiyang, China.
Int Immunopharmacol. 2022 Nov;112:109288. doi: 10.1016/j.intimp.2022.109288. Epub 2022 Sep 30.
Globally, Mechanical ventilation is the most commonly used short-term life support technology. Ventilator-induced lung injury (VILI) is an inflammatory injury caused by mechanical ventilation. MicroRNAs (miRNAs) are considered as new gene regulators that play an important role in lung injury and inflammation. However, the role and mechanism of action of miR-9a-5p in VILI remain unclear.
Herein, a rat model of VILI was established. To determine the expression levels of miR-9a-5p and CXCR4 mRNA, real-time quantitative polymerase chain reactions (qRT-PCR) were conducted. As well as western blot (WB) and immunofluorescence analyses, we determined the expression of CXCR4, SDF-1 and MAPK signaling pathway-related kinases. Hematoxylin and eosin (H&E) staining and the wet-dry ratio of the lung tissue were used to evaluate organ injury. An enzyme-linked immunosorbent assay (Elisa) and myeloperoxidase (MPO) activity measurements were performed to evaluate the inflammatory response. In addition, double luciferase reporter assays were used to verify the association between miR-9a-5p and CXCR4.
The expression of miR-9a-5p was low, whereas that of CXCR4 was high in the lung tissues of VILI rats. The overexpression of miR-9a-5p alleviated the degree of pathological injury in the lung tissues of rats with VILI, downregulating inflammatory cytokine expression and MPO activity. In the VILI rat model, miR-9a-5p targeted the negative regulation of CXCR4, and CXCR4 overexpression to reverse the lung-protective and anti-inflammatory effects of miR-9a-5p overexpression in VILI rats. miR-9a-5p also inhibited the phosphorylation of extracellular signal receptor-activated kinase (ERK), a protein related to the MAPK signaling pathway, by downregulating CXCR4 expression.
miR-9a-5p can hinder the activation of the MAPK/ERK signaling pathway and reduce inflammatory reactions and lung injury in VILI rats through the targeted regulation of CXCR4 expression. Therefore, miR-9a-5p could serve as an intervention target to supply a new strategy for the care of VILI.
在全球范围内，机械通气是最常用的短期生命支持技术。呼吸机引起的肺损伤（VILI）是一种由机械通气引起的炎症性损伤。microRNAs（miRNAs）被认为是新的基因调控因子，在肺损伤和炎症中发挥重要作用。然而，miR-9a-5p 在 VILI 中的作用和作用机制尚不清楚。
在此，建立了大鼠 VILI 模型。通过实时定量聚合酶链反应（qRT-PCR）测定 miR-9a-5p 和 CXCR4 mRNA 的表达水平。通过 Western blot（WB）和免疫荧光分析，我们测定了 CXCR4、SDF-1 和 MAPK 信号通路相关激酶的表达。苏木精和伊红（H&E）染色和肺组织的湿/干比用于评估器官损伤。酶联免疫吸附测定（ELISA）和髓过氧化物酶（MPO）活性测定用于评估炎症反应。此外，双荧光素酶报告基因实验用于验证 miR-9a-5p 与 CXCR4 之间的关联。
VILI 大鼠肺组织中 miR-9a-5p 表达水平低，而 CXCR4 表达水平高。miR-9a-5p 的过表达减轻了 VILI 大鼠肺组织的病理损伤程度，下调了炎症细胞因子的表达和 MPO 活性。在 VILI 大鼠模型中，miR-9a-5p 负调控 CXCR4，CXCR4 过表达逆转了 miR-9a-5p 过表达对 VILI 大鼠的肺保护和抗炎作用。miR-9a-5p 还通过下调 CXCR4 表达抑制细胞外信号调节激酶（ERK）的磷酸化，ERK 是 MAPK 信号通路的相关蛋白。
miR-9a-5p 可以通过靶向调节 CXCR4 表达来抑制 MAPK/ERK 信号通路的激活，减少 VILI 大鼠的炎症反应和肺损伤。因此，miR-9a-5p 可以作为一种干预靶点，为 VILI 的治疗提供新的策略。
