Lee Hwa Young, Hur Jung, Kang Ji Young, Rhee Chin Kook, Lee Sook Young
Division of Allergy, Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Allergy Asthma Immunol Res. 2021 Mar;13(2):312-329. doi: 10.4168/aair.2021.13.2.312.
MicroRNA-21 (miR-21) influences the Th2 immune pathway by suppressing the expressions of interleukin (IL)-12 and interferon (IFN)-γ. The effects of miR-21 suppression on alveolar macrophage polarization and airway inflammation are not known.
BALB/c and miR-21 knockout (KO) mice were sensitized and challenged with ovalbumin (OVA). The anti-miR-21 antagomir was administered to BALB/c mice by intranasal inhalation from the day of OVA sensitization. Changes in cell counts, cytokine levels in bronchoalveolar lavage fluid (BALF), and airway hyperresponsiveness (AHR) were examined. Total, M1, and M2 macrophages were examined in the lung tissues by immunohistochemistry (IHC). M2 macrophages from the OVA mice lung were inhaled into the anti-miR-21 antagomir-treated asthmatic mice. Moreover, the polarization of M0 to M2 macrophages upon IL-4 stimulation was analyzed after anti-miR-21 antagomir transfection.
The miR-21 KO mice showed decreases in AHR, total cell and eosinophil counts in BALF, and in the levels of IL-4, IL-5, IL-10, and IL-13. Expression of IL-12 and IFN-γ were increased in the miR-21 KO mice. Peribronchial inflammation and goblet cell dysplasia were significantly decreased in the lung tissues of miR-21 KO OVA mice compared to the wild type OVA mice. IHC for M1, M2, and total macrophage in the lung tissues showed that miR-21 inhalation suppressed alveolar M2 macrophages in KO mice. M2 macrophage inhalation restored AHR and eosinophilic airway inflammation in the miR-21 antagomir-treated mice. Moreover, anti-miR-21 antagomir transfection decreased the expression of M2 markers and increased the expression of M1 markers in M0 macrophages after IL-4 stimulation.
The results suggest that miR-21 antagonism could suppress alveolar M2 macrophage polarization, decreasing not only the Th2 eosinophilic airway inflammation but also AHR and airway remodeling process.
微小RNA-21（miR-21）通过抑制白细胞介素（IL）-12和干扰素（IFN）-γ的表达来影响Th2免疫途径。miR-21抑制对肺泡巨噬细胞极化和气道炎症的影响尚不清楚。
用卵清蛋白（OVA）对BALB/c和miR-21基因敲除（KO）小鼠进行致敏和激发。从OVA致敏当天开始，通过鼻内吸入将抗miR-21拮抗剂施用于BALB/c小鼠。检测细胞计数、支气管肺泡灌洗液（BALF）中的细胞因子水平以及气道高反应性（AHR）的变化。通过免疫组织化学（IHC）检测肺组织中的总巨噬细胞、M1巨噬细胞和M2巨噬细胞。将OVA小鼠肺中的M2巨噬细胞吸入经抗miR-21拮抗剂处理的哮喘小鼠体内。此外，在抗miR-21拮抗剂转染后，分析IL-4刺激下M0巨噬细胞向M2巨噬细胞的极化情况。
miR-21基因敲除小鼠的AHR、BALF中的总细胞和嗜酸性粒细胞计数以及IL-4、IL-5、IL-10和IL-13水平均降低。miR-21基因敲除小鼠中IL-12和IFN-γ的表达增加。与野生型OVA小鼠相比，miR-21基因敲除的OVA小鼠肺组织中的支气管周围炎症和杯状细胞发育异常明显减少。肺组织中M1、M2和总巨噬细胞的免疫组织化学检测表明，吸入miR-21可抑制基因敲除小鼠的肺泡M2巨噬细胞。吸入M2巨噬细胞可恢复经抗miR-21拮抗剂处理的小鼠的AHR和嗜酸性气道炎症。此外，抗miR-21拮抗剂转染降低了IL-4刺激后M0巨噬细胞中M2标志物的表达，并增加了M1标志物的表达。
结果表明，拮抗miR-21可抑制肺泡M2巨噬细胞极化，不仅可减少Th2嗜酸性气道炎症，还可降低AHR和气道重塑过程。
