Susceptibility for cigarette smoke-induced DAMP release and DAMP-induced inflammation in COPD

Abstract

Cigarette smoke (CS) exposure is a major risk factor for chronic obstructive pulmonary disease (COPD). We investigated whether CS-induced damage-associated molecular pattern (DAMP) release or DAMP-mediated inflammation contributes to susceptibility for COPD. Samples, including bronchial brushings, were collected from young and old individuals, susceptible and nonsusceptible for the development of COPD, before and after smoking, and used for gene profiling and airway epithelial cell (AEC) culture. AECs were exposed to CS extract (CSE) or specific DAMPs. BALB/cByJ and DBA/2J mice were intranasally exposed to LL-37 and mitochondrial (mt)DAMPs. Functional gene-set enrichment analysis showed that CS significantly increases the airway epithelial gene expression of DAMPs and DAMP receptors in COPD patients. In cultured AECs, we observed that CSE induces necrosis and DAMP release, with specifically higher galectin-3 release from COPD-derived compared with control-derived cells. Galectin-3, LL-37, and mtDAMPs increased CXCL8 secretion in AECs. LL-37 and mtDAMPs induced neutrophilic airway inflammation, exclusively in mice susceptible for CS-induced airway inflammation. Collectively, we show that in airway epithelium from COPD patients, the CS-induced expression of DAMPs and DAMP receptors in vivo and the release of galectin-3 in vitro is exaggerated. Furthermore, our studies indicate that a predisposition to release DAMPs and subsequent induction of inflammation may contribute to the development of COPD.

Association of urine mitochondrial DNA with clinical measures of COPD in the SPIROMICS cohort

“…One underlying biological mechanism that may provide insight into COPD pathogenesis and progression is mitochondrial dysfunction, which is consistently observed in cells derived from COPD subjects (5)(6)(7)(8)(9)(10)(11)(12)(13), as well as in experimental COPD models (11,14). Such mitochondrial dysfunction is associated with the leakage of mitochondrial DNA (mtDNA) (15)(16)(17)(18)(19), a mitochondrial derived danger-associated molecular pattern (mtDAMP) (20,21). Intracellularly, mtDNA acts as an essential second messenger that activates pathogen recognition receptors (PRRs) -in particular, the NLRP3 inflammasome and the DNA sensor cyclic GMP-AMP synthase (cGAS), eliciting a series of innate immune signaling cascades (21)(22)(23)(24).…”

Respiratory

“…Understanding genetics is also key to unraveling the causes and potential future treatments for many lung diseases. Those patients with both genetic and environmental determinants, such as in those who smoke and have genes associated with COPD, are at the greatest risk [228].…”

Cigarette smoke exposure decreases CFLAR expression in bronchial epithelium, augmenting susceptibility for cell death and DAMP release

“…Significance between the scrambled control and the siRNA-treated cells over the range of concentrations was tested using a two-way ANOVA with Bonferroni correction, # p < 0.05. cigarette smoke-induced airway inflammation in mice 19 . Moreover, this DAMP is specifically released upon cell death and a reliable marker for CSE-induced DAMP release from primary bronchial epithelial cells 8 . In the current study we observed an increase in dsDNA and RNA release in CFLAR deficient cells upon CSE exposure.…”

“…Cells were grown to confluence and serum-deprived overnight before use. Cigarette smoke extract (CSE) was prepared as described before with two filterless Kentucky 3R4F research-reference SCIENTIfIC REPORtS | (2018) 8:12426 | DOI:10.1038/s41598-018-30602-7 cigarettes and a Watson Marlow 603S smoking pump at a rate of 8 L/hr (Watson-Marlow, Delden, The Netherlands) 5,8 . The 100% CSE mixture was prepared by bubbling the CS of two cigarettes through 25 mL of RPMI-1640 medium supplemented with 100 U/ml penicillin and 100 mg/mL streptomycin.…”