Yes激酶相关蛋白活化对急性肺损伤修复的影响及其机制

目的:探讨Yes激酶相关蛋白（YAP）活化对感染性急性肺损伤修复的影响及可能机制。方法:SPF级雄性ICR小鼠90只，随机分为2组，LPS组和LPS+XMU组。LPS组腹腔注射脂多糖（LPS）（7.5 mg/kg），LPS+XMU组在给予LPS的同时腹腔注射XMU-MP-1（YAP激动剂）（1 mg·kg-1·d-1，连续3 d）。在给予LPS 0 h、24 h、48 h、72 h后，采用苏木素-伊红（HE）染色观察肺组织形态。制备小鼠肺泡灌洗液，BCA法检测总蛋白含量，酶联免疫吸附法（ELISA）检测TNF-α和IL-6含量，比色法检测髓过氧化物酶（MPO）活性。Western blot法检测小鼠肺细胞核内YAP及胞浆磷酸化YAP（P-YAP）、肺组织YAP靶基因-结缔组织生长因子（CTGF）及增殖细胞核抗原（PCNA）蛋白的表达。结果:与LPS组比较，LPS+XMU组核内YAP蛋白表达在24 h、48 h、72 h表达分别上调39.2%、148.1%和42.9%（P均<0.05），同时YAP下游靶蛋白CTGF蛋白表达分别上调186.6%、10.1%、146.1%（P均<0.05），而胞浆中P-YAP显著下调。与LPS组比较，LPS+XMU 24 h组肺泡灌洗液中IL-6和TNF-α含量分别降低28.4%和23.7%，48 h组肺泡灌洗液MPO活性和TNF-α含量分别降低13.5%和39.5%，72 h组肺泡灌洗液IL-6和TNF-α含量分别降低42.8%和16.7%（P均<0.05）。与LPS组比较，LPS+XMU 24 h组肺组织PCNA蛋白表达无统计学差异，而48 h、72 h PCNA表达分别上调44.2%、14.9%（P均<0.05）。与LPS组比较，LPS+XMU 24 h组、48 h组和72 h组肺泡灌洗液蛋白含量分别降低32.4%、46.0%和26.3%（P均<0.05）。HE染色结果显示，与LPS组比较，LPS+XMU组肺组织炎症细胞渗出减少，肺泡壁重构增加，肺组织修复明显加快。结论:YAP活化通过多种机制来改善肺损伤，促进肺损伤修复，损伤期抑制炎症，修复期促进炎症消减和诱导细胞增殖。

Stimulation of Yes-associated protein activity attenuates lung injury repair induced by LPS in mice

AIM: To observe the effect and possible mechanism of stimulation of Yes-associated protein (YAP) activity on acute lung injury and repair induced by LPS in mice. METHODS: Ninety adult male ICR mice were divided into two groups: acute lung injury model group induced by LPS (7.5 mg/kg, i.p.) and LPS+XMU treatment (1 mg·kg-1·d-1) group. At 0 h, 24 h, 48 h and 72 h after LPS injection, the contents of TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF) were detected by ELISA method. The activity of myeloperoxidase (MPO) and the content of protein in BALF were evaluated by chemical technique. The protein level of nuclear YAP, cytosol phosphorylated YAP (P-YAP), connective tissue growth factor (CTGF) and proliferating cell nuclear antigen (PCNA) in lung were analyzed by Western blot. RESULTS:The protein level of nuclear YAP at 24 h, 48 h and 72 h in lung of LPS+XMU group were up-regulated than those of LPS group by 39.2%, 148.1% and 42.9%, and the protein level of CTGF in lung were up-regulated than those of LPS group by 186.6%, 10.1% and 146.1% (P<0.05), respectively, while the protein level of cytosol P-YAP was down-regulated. The content of IL-6 and TNF-α at 24 h in BALF of LPS+XMU group were lower than those of LPS group by 28.4% and 23.7%, and the activity of MPO and the content of TNF-α at 48 h in BALF were lower by 13.5% and 39.5%, and the content of IL-6 and TNF-α at 72 h in BALF were lower by 42.8% and 16.7% (P<0.05), respectively. The protein level of PCNA at 48 h and 72 h in lung of LPS+XMU group were up-regulated than those of LPS group by 44.2% and 14.9% (P<0.05), respectively, while there was no significant difference at 24 h. The content of protein at 24 h, 48 h and 72 h in BALF of LPS+XMU group were lower than those of LPS group by 32.4%, 46.0% and 26.3% (P<0.05), respectively. The pathological changes showed a significantly attenuated tissue injury and accelerated recovery from lung injury in LPS+XMU group compared with mice injected with LPS alone at each times point. CONCLUSION: Stimulation of YAP activity attenuates lung injury and promotes lung recovery by alleviating lung inflammation and injury at injury phase, but by promoting inflammation resolution and stimulating cell proliferation at repair phase.