A potential role of microvesicle-containing miR-223/142 in lung inflammation

Abstract

BackgroundUncontrolled lung inflammation is one of the prominent features in the pathogenesis of lung infection- associated acute lung injury (ALI). Microvesicles (MVs) are extracellular nanovesicles that are generated via direct membrane budding.MethodsBronchoalveolar lavage fluid (BALF) samples were collected from mice with or without intratracheal lipopolysaccharide (LPS) instillation. BALF MVs were characterised and MV-containing microRNA (miRNA) profiles were assessed and confirmed. Secretion and function of MV-containing miR-223/142 (MV-miR-223/142) were analysed in vivo.ResultsIn BALF, MVs are mainly derived from macrophages in response to LPS. After intratracheal instillation (i.t.) of LPS or Klebsiella pneumoniae, MV-containing miR-223/142 are dramatically induced in both BALF and serum. Mechanistically, miRNA 3′ end uridylation mediates the packing of miR-223/142 into MVs. To investigate the functional role of MV-miR-223/142, we loaded miR-223/142 mimics into unstimulated MVs and delivered them into the murine lungs via i.t. The miR-223/142 mimics-enriched MVs selectively targeted lung macrophages and suppressed the inflammatory lung responses that were triggered by LPS or K. pneumoniae. Mechanistically, miR-223 and miR-142 synergistically suppress Nlrp3 inflammasome activation in macrophages via inhibition of Nlrp3 and Asc, respectively.ConclusionsIn the pathogenesis of lung macrophage-mediated inflammatory responses, MV-miR-223/142 secretion is robustly enhanced and detectable in BALF and serum. Furthermore, restoration of intracellular miR-223/142 via vesicle-mediated delivery suppresses macrophage activation and lung inflammation via inhibition of Nlrp3 inflammasome activation.

Emerging role of extracellular vesicles in the respiratory system

“…In 2007, EVs containing miRNAs (EV-miRNAs) and other noncoding RNAs were first discovered 14 . Interestingly, EV-miRNAs are suspected to be released during sterile and nonsterile lung damage in mice 6 , 8 , 9 , 25 and are significantly involved in the development of lung inflammation 6 , 25 . Studies in hyperoxia-associated oxidative stress have demonstrated a dramatic shift in EV-miRNA profiles in vivo after hyperoxia is induced 7 .…”

The Inhibition of P-Selectin Reduced Severe Acute Lung Injury in Immunocompromised Mice

“…Oxidative Medicine and Cellular Longevity pneumonia in hospitals. In recent years, the incidence of Klebsiella pneumoniae has been on the rise [34,35]. Kidney transplant patients are typical immunocompromised hosts.…”

ADAM15 expression is increased in lung CD8+ T cells, macrophages, and bronchial epithelial cells in patients with COPD and is inversely related to airflow obstruction

“…Human ADAM15 cDNA (isoform 6 pre-proprotein as the longest transcript variant) amplified using RT-PCR was subcloned into the BamHI and XhoI sites of the pcDNA3.1 vector to obtain pcDNA- ADAM15 (the primer sequences used for cloning were: forward: 5′-CGCGGTACCATGCGGCTGGCGCTGCTCTGGG-3′; reverse: 5′-CCGCTCGAGTCAGAGGTAG-AGCGAGGACACT-3′). THP-1 cells (human monocyte-like cells; ATCC, Manassas, VA) were maintained in RPMI-1640 containing 10% fetal bovine serum and differentiated into macrophage-like cells by incubating them with 150 nM phorbol myristate acetate for 24 h. Cells were electroporated (Neon Transfection System; Thermo Fisher Scientific, Waltham, MA) with either the ADAM15 or the control (pcDNA3.1) vector [ 20 ]. ADAM15 expression was measured using quantitative RT RT-PCR and the THP-1 cells were treated with 5% CSE for up to 24 h. C-C motif chemokine ligand-2 (CCL-2), tumor necrosis factor-α (TNF-α), MMP-9, and MMP-12 levels were measured in the cell culture supernatants using ELISAs (R&D Systems, Minneapolis, MN).…”