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Abstract：
Cigarette smoke extract (CSE)-treated mouse airway epithelial cells (MAECs)-derived exosomes accelerate the progression of chronic obstructive pulmonary disease (COPD) by upregulating triggering receptor expressed on myeloid cells 1 (TREM-1); however, the specific mechanism remains unclear. We aimed to explore the potential mechanisms of CSE-treated MAECs-derived exosomes on M1 macrophage polarization and pyroptosis in COPD. In vitro, exosomes were extracted from CSE-treated MAECs, followed by co-culture with macrophages. In vivo, mice exposed to cigarette smoke (CS) to induce COPD, followed by injection or/and intranasal instillation with oe-TREM-1 lentivirus. Lung function and pathological changes were evaluated. CD68+ cell number and the levels of iNOS, TNF-α, IL-1β (M1 macrophage marker), and pyroptosis-related proteins (NOD-like receptor family pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-1 recruitment domain, caspase-1, cleaved-caspase-1, gasdermin D [GSDMD], and GSDMD-N) were examined. The expression of maternally expressed gene 3 (MEG3), spleen focus forming virus proviral integration oncogene (SPI1), methyltransferase 3 (METTL3), and TREM-1 was detected and the binding relationships among them were verified. MEG3 increased N6-methyladenosine methylation of TREM-1 by recruiting SPI1 to activate METTL3. Overexpression of TREM-1 or METTL3 negated the alleviative effects of MEG3 inhibition on M1 polarization and pyroptosis. In mice exposed to CS, EXO-CSE further aggravated lung injury, M1 polarization, and pyroptosis, which were reversed by MEG3 inhibition. TREM-1 overexpression negated the palliative effects of MEG3 inhibition on COPD mouse lung injury. Collectively, CSE-treated MAECs-derived exosomal long non-coding RNA MEG3 may expedite M1 macrophage polarization and pyroptosis in COPD via the SPI1/METTL3/TREM-1 axis.
摘要：
香烟烟雾提取物（CSE）处理的小鼠气道上皮细胞（MAECs）来源的外泌体通过上调髓样细胞1（TREM-1）上表达的触发受体加速慢性阻塞性肺疾病（COPD）的进展；然而，具体机制尚不清楚.我们旨在探讨CSE处理的MAECs来源的外泌体对COPD中M1巨噬细胞极化和焦亡的潜在机制。体外，从CSE处理的MAECs中提取外泌体，然后与巨噬细胞共培养。在体内,暴露于香烟烟雾（CS）的小鼠诱发COPD，然后注射或/和鼻内滴注oe-TREM-1慢病毒。评估肺功能和病理变化。CD68+细胞数量和iNOS水平，TNF-α,IL-1β（M1巨噬细胞标记），和焦亡相关蛋白（含NOD样受体家族pyrin结构域3，含caspase-1募集结构域的凋亡相关斑点样蛋白，caspase-1,cleaved-caspase-1,gasderminD[GSDMD],和GSDMD-N)进行了检查。母体表达基因3（MEG3）的表达，脾焦点形成病毒前病毒整合癌基因（SPI1），甲基转移酶3(METTL3)，检测TREM-1并验证它们之间的结合关系。MEG3通过募集SPI1激活METTL3来增加TREM-1的N6-甲基腺苷甲基化。TREM-1或METTL3的过表达否定了MEG3抑制对M1极化和焦亡的缓解作用。在暴露于CS的小鼠中，EXO-CSE进一步加重肺损伤，M1极化，和焦亡，被MEG3抑制逆转。TREM-1过表达否定了MEG3抑制对COPD小鼠肺损伤的姑息作用。总的来说，CSE处理的MAECs来源的外泌体长非编码RNAMEG3可能通过SPI1/METTL3/TREM-1轴加速COPD中的M1巨噬细胞极化和焦亡。
