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Huang H, Zhu J, Gu L, Hu J, Feng X, Huang W, Wang S, Yang Y, Cui P, Lin SH, Suen A, Shimada BK, Williams B, Kane MA, Ke Y, Zhang CO, Birukova AA, Birukov KG, Chao W, Zou L. TLR7 Mediates Acute Respiratory Distress Syndrome in Sepsis by Sensing Extracellular miR-146a. Am J Respir Cell Mol Biol 2022; 67:375-388. [PMID: 35679261 PMCID: PMC9447138 DOI: 10.1165/rcmb.2021-0551oc] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/09/2022] [Indexed: 12/15/2022] Open
Abstract
TLR7 (Toll-like receptor 7), the sensor for single-stranded RNA, contributes to systemic inflammation and mortality in murine polymicrobial sepsis. Recent studies show that extracellular miR-146a-5p serves as a TLR7 ligand and plays an important role in regulating host innate immunity. However, the role of miR-146a-5p and TLR7 signaling in pulmonary inflammation, endothelial activation, and sepsis-associated acute respiratory distress syndrome remains unclear. Here, we show that intratracheal administration of exogenous miR-146a-5p in mice evokes lung inflammation, activates endothelium, and increases endothelial permeability via TLR7-dependent mechanisms. TLR7 deficiency attenuates pulmonary barrier dysfunction and reduces lung inflammatory response in a murine sepsis model. Moreover, the impact of miR-146a-5p-TLR7 signaling on endothelial activation appears to be a secondary effect because TLR7 is undetectable in the human pulmonary artery and microvascular endothelial cells (ECs), which show no response to direct miR-146a-5p treatment in vitro. Both conditioned media of miR-146a-5p-treated macrophages (Mϕ) and septic sera of wild-type mice induce a marked EC barrier disruption in vitro, whereas Mϕ conditioned media or septic sera of TLR7-/- mice do not exhibit such effect. Cytokine array and pathway enrichment analysis of the Mϕ conditioned media and septic sera identify TNFα (tumor necrosis factor α) as the main downstream effector of miR-146a-5p-TLR7 signaling responsible for the EC barrier dysfunction, which is further supported by neutralizing anti-TNFα antibody intervention. Together, these data demonstrate that TLR7 activation elicits pulmonary inflammation and endothelial barrier disruption by sensing extracellular miR-146a-5p and contributes to sepsis-associated acute respiratory distress syndrome.
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Affiliation(s)
- Huang Huang
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Jing Zhu
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Lili Gu
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Jiang Hu
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Xiujing Feng
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Sheng Wang
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Yang Yang
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Ping Cui
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Shao-Hsuan Lin
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Andrew Suen
- Center for Shock, Trauma, and Anesthesiology Research and
| | | | | | - Maureen A. Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Yunbo Ke
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Chen-ou Zhang
- Division of Pulmonary and Critical Care Medicine, School of Medicine, and
| | - Anna A. Birukova
- Division of Pulmonary and Critical Care Medicine, School of Medicine, and
| | - Konstantin G. Birukov
- Center for Shock, Trauma, and Anesthesiology Research and
- Division of Pulmonary and Critical Care Medicine, School of Medicine, and
| | - Wei Chao
- Center for Shock, Trauma, and Anesthesiology Research and
| | - Lin Zou
- Center for Shock, Trauma, and Anesthesiology Research and
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