Caspase-1-mediated extracellular vesicles derived from pyroptotic alveolar macrophages promote inflammation in acute lung injury

作者：Xichun Qin, Yueyuan Zhou, Caili Jia, Zhixiang Chao, Hao Qin, Jingtian Liang, Xiucheng Liu, Zhiwei Liu, Teng Sun, Yanliang Yuan, Hao Zhang · 发表于：International Journal of Biological Sciences · 年份：2022 · DOI：10.7150/ijbs.66477 · 被引用次数：56 · 研究领域：Extracellular vesicles in disease、Inflammasome and immune disorders、Heme Oxygenase-1 and Carbon Monoxide

The occurrence and development of acute lung injury (ALI) involve a variety of pathological factors and complex mechanisms. How pulmonary cells communicate with each other and subsequently trigger an inflammatory cascade remains elusive. Extracellular vesicles (EVs) are a critical class of membrane-bound structures that have been widely investigated for their roles in pathophysiological processes, especially in immune responses and tumor progression. Most of the current knowledge of the functions of EVs is related to functions derived from viable cells (e.g., microvesicles and exosomes) or apoptotic cells (e.g., apoptotic bodies); however, there is limited understanding of the rapidly progressing inflammatory response in ALI. Herein, a comprehensive analysis of micron-sized EVs revealed a mass production of 1-5 μm pyroptotic bodies (PyrBDs) release in the early phase of ALI induced by lipopolysaccharide (LPS). Alveolar macrophages were the main source of PyrBDs in the early phase of ALI, and the formation and release of PyrBDs were dependent on caspase-1. Furthermore, PyrBDs promoted the activation of epithelial cells, induced vascular leakage and recruited neutrophils through delivery of damage-associated molecular patterns (DAMPs). Collectively, these findings suggest that PyrBDs are mainly released by macrophages in a caspase-1-dependent manner and serve as mediators of LPS-induced ALI.