背景:病毒性肺炎,比如SARS和MERS,一直是公共医疗系统的经常性挑战。COVID-19引发了前所未有的全球危机。病毒性肺炎的主要影响是肺组织的病理变化。然而,SP-B位点基因多态性对病毒性肺炎患者肺泡表面张力的影响尚待研究.
目的:通过体内动物实验和临床试验,探讨SP-B1580位点基因多态性通过细胞焦亡信号通路调节病毒性肺炎肺表面活性物质张力的分子机制。
方法:我们构建了病毒性肺炎的转基因小鼠模型,并通过气管内注射给予H5N1流感病毒。48小时后,评价各组小鼠的存活率。肺组织,血,收集支气管肺泡灌洗液样本进行组织病理学分析。使用ELISA测量炎症因子浓度。使用TUNEL测定法测定细胞凋亡的水平。使用qRT-PCR和蛋白质印迹评估细胞死亡相关因子表达的变化。此外,对病毒性肺炎患者的血液样本进行分析,以检测单核苷酸多态性并探讨其与疾病严重程度的相关性,炎症因子水平,和肺表面活性蛋白表达。
结果:H5N1感染小鼠后,模型组和hSP-B-C组24h内死亡率高。空白对照组的生存率,病毒模型组,hSP-B-C组,而hSP-B-T组为100%,50%,37.5%,75%,分别。组织学分析显示明显的肺组织损伤,拥塞,肺泡破坏,模型组和hSP-B-C组肺泡间隔增厚。然而,hSP-B-T组这些肺部病变明显减轻.模型组和hSP-B-C组炎症因子水平升高,而hSP-B-T组炎症因子水平降低。TUNEL测定显示hSP-B-T组的肺中凋亡细胞减少。此外,SP-B和细胞死亡相关蛋白的表达在三组中均下调,在hSP-B-C组中观察到最低的表达。临床试验发现重症病毒性肺炎患者CC基因型和C等位基因频率较高,与轻中度病毒性肺炎患者相比,炎症因子水平升高和SP-B表达降低。
结论:1580位点的SP-B多态性通过细胞焦亡信号通路调节肺表面活性物质张力,从而影响病毒性肺炎的进展。
BACKGROUND: Viral pneumonias, such as SARS and MERS, have been a recurrent challenge for the public healthcare system. COVID-19 posed an unprecedented global crisis. The primary impact of viral pneumonia is pathologic changes of lung tissue. However, the effect of SP-B site gene polymorphism on alveolar surface tension in viral pneumonia remains unexplored.
OBJECTIVE: To explore the molecular mechanism of how the gene polymorphism at SP-B 1580 site regulates the pulmonary surfactant tension of viral pneumonia through the cellular pyroptosis signaling pathway using an in vivo animal experiment and a clinical trial.
METHODS: We constructed a genetically modified mouse model of viral pneumonia and administered H5N1 influenza virus through intratracheal injection. After 48 hours, the survival rate of each mouse group was evaluated. Lung tissue, blood, and bronchoalveolar lavage fluid samples were collected for histopathologic analysis. Inflammatory factor concentrations were measured using ELISA. The level of apoptosis was determined using TUNEL assay. Changes in the expression of cell death-related factors were assessed using qRT-PCR and protein blotting. Additionally, blood samples from patients with viral pneumonia were analyzed to detect single nucleotide polymorphisms and explore their correlation with disease severity, inflammatory factor levels, and pulmonary surfactant protein expression.
RESULTS: Following H5N1 infection of mice, the model group and hSP-B-C group showed high mortality rates within 24 hours. The survival rates in the blank control group, virus model group, hSP-B-C group, and hSP-B-T group were 100%, 50%, 37.5%, and 75%, respectively. Histologic analysis revealed significant lung tissue damage, congestion, alveolar destruction, and thickened alveolar septa in the model and hSP-B-C groups. However, these pulmonary lesions were significantly alleviated in the hSP-B-T group. Inflammatory factor levels were elevated in the model and hSP-B-C groups but reduced in the hSP-B-T group. TUNEL assay demonstrated a decrease in apoptotic cells in the lungs of the hSP-B-T group. Furthermore, the expression of SP-B and cell death-related proteins was downregulated in all three groups, with the lowest expression observed in the hSP-B-C group. The clinical trial found that patients with severe viral pneumonia exhibited a higher frequency of CC genotype and C allele in, along with increased inflammatory factor levels and decreased SP-B expression compared to those with mild-to-moderate viral pneumonia.
CONCLUSIONS: SP-B polymorphism at the 1580 site regulates lung surfactant tension through the cell pyroptosis signaling pathway, thus affecting the progression of viral pneumonia.