Mitra Srabani, Wewers Mark D, Sarkar Anasuya
Davis Heart and Lung Research Institute, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States of America.
PLoS One. 2015 Dec 28;10(12):e0145607. doi: 10.1371/journal.pone.0145607. eCollection 2015.
Lung endothelial cell apoptosis and injury occurs throughout all stages of acute lung injury (ALI/ARDS) and impacts disease progression. Lung endothelial injury has traditionally been focused on the role of neutrophil trafficking to lung vascular integrin receptors induced by proinflammatory cytokine expression. Although much is known about the pathogenesis of cell injury and death in ALI/ARDS, gaps remain in our knowledge; as a result of which there is currently no effective pharmacologic therapy. Enzymes known as caspases are essential for completion of the apoptotic program and secretion of pro-inflammatory cytokines. We hypothesized that caspase-1 may serve as a key regulator of human pulmonary microvascular endothelial cell (HPMVEC) apoptosis in ALI/ARDS. Our recent experiments confirm that microparticles released from stimulated monocytic cells (THP1) induce lung endothelial cell apoptosis. Microparticles pretreated with the caspase-1 inhibitor, YVAD, or pan-caspase inhibitor, ZVAD, were unable to induce cell death of HPMVEC, suggesting the role of caspase-1 or its substrate in the induction of HPMVEC cell death. Neither un-induced microparticles (control) nor direct treatment with LPS induced apoptosis of HPMVEC. Further experiments showed that caspase-1 uptake into HPMVEC and the induction of HPMVEC apoptosis was facilitated by caspase-1 interactions with microparticulate vesicles. Altering vesicle integrity completely abrogated apoptosis of HPMVEC suggesting an encapsulation requirement for target cell uptake of active caspase-1. Taken together, we confirm that microparticle centered caspase-1 can play a regulator role in endothelial cell injury.
肺内皮细胞凋亡和损伤发生在急性肺损伤（ALI/ARDS）的各个阶段，并影响疾病进展。传统上，肺内皮损伤一直聚焦于促炎细胞因子表达诱导的中性粒细胞向肺血管整合素受体的转运作用。尽管我们对ALI/ARDS中细胞损伤和死亡的发病机制了解很多，但仍存在知识空白；因此，目前尚无有效的药物治疗方法。被称为半胱天冬酶的酶对于凋亡程序的完成和促炎细胞因子的分泌至关重要。我们假设半胱天冬酶-1可能是ALI/ARDS中人类肺微血管内皮细胞（HPMVEC）凋亡的关键调节因子。我们最近的实验证实，受刺激的单核细胞（THP1）释放的微粒可诱导肺内皮细胞凋亡。用半胱天冬酶-1抑制剂YVAD或泛半胱天冬酶抑制剂ZVAD预处理的微粒无法诱导HPMVEC细胞死亡，这表明半胱天冬酶-1或其底物在诱导HPMVEC细胞死亡中起作用。未诱导的微粒（对照）和直接用脂多糖处理均未诱导HPMVEC凋亡。进一步的实验表明，半胱天冬酶-1与微粒囊泡的相互作用促进了半胱天冬酶-1被HPMVEC摄取以及HPMVEC凋亡的诱导。改变囊泡完整性完全消除了HPMVEC的凋亡，这表明活性半胱天冬酶-1靶向细胞摄取需要封装。综上所述，我们证实以微粒为中心的半胱天冬酶-1可在内皮细胞损伤中发挥调节作用。
