Abstract
Exposure to airborne particulate matter (PM)not only causes lung inflammation and chronic respiratory diseases, but also increases the incidence and mortality of cardiopulmonary diseases. The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3)inflammasome activation has been shown to play a critical role in the formation of many chronic disorders. On the other hand, carbon monoxide (CO)has been shown to possess anti-inflammatory and antioxidant effects in many tissues and organs. Here, we investigated the effects and mechanisms of carbon monoxide releasing molecule-2 (CORM-2)on PM-induced inflammatory responses in human pulmonary alveolar epithelial cells (HPAEpiCs). We found that PM induced C-reactive protein (CRP)expression, NLRP3 inflammasome activation, IL-1β secretion, and caspase-1 activation, which were inhibited by pretreatment with CORM-2. In addition, transfection with siRNA of Toll-like receptor 2 (TLR2)or TLR4 and pretreatment with an antioxidant (N-acetyl-cysteine, NAC), the inhibitor of NADPH oxidase (diphenyleneiodonium, DPI), or a mitochondria-specific superoxide scavenger (MitoTEMPO)reduced PM-induced inflammatory responses. CORM-2 also inhibited PM-induced NADPH oxidase activity and NADPH oxidase- and mitochondria-derived ROS generation. However, pretreatment with inactivate CORM-2 (iCORM-2)had no effects on PM-induced inflammatory responses. Finally, we showed that CORM-2 inhibited PM-induced CRP, NLRP3 inflammasome, and ASC protein expression in the lung tissues of mice and IL-1β levels in the serum of mice. PM-enhanced leukocyte count in bronchoalveolar lavage fluid in mice was reduced by CORM-2. The results of this study suggested a protective role of CORM-2 in PM-induced lung inflammation by inhibiting the TLR2 and TLR4/ROS-NLRP3 inflammasome-CRP axial.
Original language | English |
---|---|
Pages (from-to) | 163-174 |
Number of pages | 12 |
Journal | Molecular Immunology |
Volume | 112 |
DOIs | |
Publication status | Published - Aug 1 2019 |
Keywords
- Carbon monoxide
- Inflammasome
- Lung inflammation
- Particulate matter
- Reactive oxygen species
ASJC Scopus subject areas
- Immunology
- Molecular Biology