PDF(Pubmed)
Abstract：
The pulmonary endothelium is a dynamic and metabolically active monolayer of endothelial cells. Dysfunction of the pulmonary endothelial barrier plays a crucial role in the acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), frequently observed in the context of viral pneumonia. Dysregulation of tight junction proteins can lead to the disruption of the endothelial barrier and subsequent leakage. Here, the highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) served as an ideal model for studying ALI and ARDS. The alveolar lavage fluid of pigs infected with HP-PRRSV, and the supernatant of HP-PRRSV infected pulmonary alveolar macrophages were respectively collected to treat the pulmonary microvascular endothelial cells (PMVECs) in Transwell culture system to explore the mechanism of pulmonary microvascular endothelial barrier leakage caused by viral infection. Cytokine screening, addition and blocking experiments revealed that proinflammatory cytokines IL-1β and TNF-α, secreted by HP-PRRSV-infected macrophages, disrupt the pulmonary microvascular endothelial barrier by downregulating claudin-8 and upregulating claudin-4 synergistically. Additionally, three transcription factors interleukin enhancer binding factor 2 (ILF2), general transcription factor III C subunit 2 (GTF3C2), and thyroid hormone receptor-associated protein 3 (THRAP3), were identified to accumulate in the nucleus of PMVECs, regulating the transcription of claudin-8 and claudin-4. Meanwhile, the upregulation of ssc-miR-185 was found to suppress claudin-8 expression via post-transcriptional inhibition. This study not only reveals the molecular mechanisms by which HP-PRRSV infection causes endothelial barrier leakage in acute lung injury, but also provides novel insights into the function and regulation of tight junctions in vascular homeostasis.
摘要：
肺内皮是内皮细胞的动态和代谢活性单层。肺内皮屏障功能障碍在急性肺损伤(ALI)和急性呼吸窘迫综合征(ARDS)经常在病毒性肺炎的背景下观察到。紧密连接蛋白的失调可导致内皮屏障的破坏和随后的渗漏。这里,高致病性猪繁殖与呼吸综合征病毒（HP-PRRSV）是研究ALI和ARDS的理想模型。感染HP-PRRSV的猪的肺泡灌洗液,分别收集HP-PRRSV感染的肺泡巨噬细胞上清液，在Transwell培养系统中处理肺微血管内皮细胞（PMVECs），以探讨病毒感染引起肺微血管内皮屏障渗漏的机制。细胞因子筛查,添加和阻断实验表明，促炎细胞因子IL-1β和TNF-α，由HP-PRRSV感染的巨噬细胞分泌，通过协同下调claudin-8和上调claudin-4来破坏肺微血管内皮屏障。此外,三种转录因子白细胞介素增强子结合因子2（ILF2），通用转录因子IIIC亚基2（GTF3C2），和甲状腺激素受体相关蛋白3（THRAP3），被确定在PMVECs的细胞核中积累，调节claudin-8和claudin-4的转录。同时,发现ssc-miR-185的上调通过转录后抑制抑制claudin-8的表达.本研究不仅揭示了HP-PRRSV感染引起急性肺损伤内皮屏障渗漏的分子机制,而且还提供了对血管内稳态中紧密连接的功能和调节的新见解。
