Objective: To investigate the role and mechanism of progranulin (PGRN) in asthma. Methods: Control group and model group were set up in wild and IL-6 knockout (IL-6 ko) mice, respectively. For asthma model, mice were intraperitoneally sensitized with 100 μg OVA on days 0 and 7, followed by aerosol challenges with 5% OVA for 30 min per day from day 14 to 21, and mice were sacrificed 24 h after the last challenge. The mice in control group were treated in the same way with PBS. Bronchoalveolar lavage fluid (BALF) was collected for leukocytes count and differential count. The pathological changes of lung tissues were observed by H&E staining. The cytokines in lung homogenate, serum and BALF were detected by Q-PCR and ELISA. The in vitro model of asthma was induced by stimulating A549 or BEAS-2B cells with IL-13. Each group was replicated in three wells and four groups were designed: PBS group, IL-13 treatment group, IL-13 + rhPGRN treatment group, inhibitors of p38 phosphorylation (SB203508) treatment group. The cells or supernatant were collected after 0~48 h. PGRN and IL-6 levels were determined by Q-PCR and ELISA, the level of p38 phosphorylation was tested by Western blot (WB). Results: Compared with control group, PGRN levels were decreased in lung homogenate and BALF (P＜0.05), and PGRN presented a downtrend in serum, however, the level of IL-6 in BALF was increased in asthma mice (P＜0.01). In IL-6 ko asthma mice, compared with the wild asthma mice, leukocytes, especially neutrophils in BALF were decreased (P＜0.05), but PGRN was increased (P＜0.05), lung pathological damage was significantly alleviated. In vitro experiments, compared with PBS group, PGRN level was decreased (P＜0.05), IL-6 level was increased (P＜0.01), phosphorylation of p38 was activated in IL-13 treatment group. Compared with IL-13 treatment group, in IL-13 + PGRN treatment group, IL-6 level was decreased (P＜0.05); phosphorylation of p38 was inhibited (P＜0.05); and the production of IL-6 (P＜0.05) was decreased after treatment with inhibitor of p38 phosphorylation. Conclusion: PGRN inhibited the production of IL-6 by suppressing the p38 phosphorylation to alleviate asthmatic airway inflammation.
目的: 探究颗粒蛋白前体(PGRN)在过敏性哮喘中的作用及机制。方法: 分别在野生鼠和IL-6 缺陷鼠中设置对照组和哮喘模型组,每组8只。模型组中,在第0日和第7日致敏小鼠(腹腔注射OVA 100 μg),从第14日起连续激发8 d(5％OVA雾化吸入,30 min/d,每日1次),末次激发24 h后取标本;对照组用PBS代替OVA做相同处理。采集支气管肺泡灌洗液(BALF)进行白细胞计数和分类计数;HE染色观察肺组织病理情况;Q-PCR及ELISA检测小鼠肺匀浆、血清和BALF中细胞因子水平。用IL-13刺激A549或BEAS-2B细胞建立体外哮喘炎症模型,每组3个复孔,共4组:PBS处理组、IL-13处理组、IL-13与重组人PGRN蛋白(rhPGRN)共同处理组及p38磷酸化抑制剂(SB203508)处理组。0 min~48 h后收集细胞及上清,用Q-PCR及ELISA检测PGRN和IL-6的表达;Western blot检测p38的磷酸化。结果: 与对照组相比,哮喘组小鼠肺匀浆和BALF中PGRN均显著降低(P＜ 0.01),血清PGRN有降低的趋势,然而哮喘小鼠BALF中IL-6显著升高(P＜0.05)。与野生鼠哮喘组相比,IL-6缺陷鼠哮喘组BALF中白细胞总数降低(P＜0.05),中性粒细胞数降低(P＜0.05),PGRN显著升高(P＜0.05),肺部病理损伤也减轻。体外实验中,IL-13处理组与PBS处理组相比,PGRN显著降低(P＜0.05),IL-6显著增高(P＜ 0.05),p38的磷酸化增加;p38抑制剂处理组比未处理组中IL-6水平降低(P＜0.05)。IL-13与rhPGRN共同处理组的IL-6显著低于IL-13处理组(P＜0.05),p38的磷酸化降低(P＜0.05)。结论: PGRN通过抑制p38磷酸化降低IL-6水平从而减轻哮喘小鼠气道炎症。.
Keywords: PGRN; airway inflammation; asthma; interleukin-6; mice.