Role of OSGIN1 in Mediating Smoking-induced Autophagy in the Human Airway Epithelium [RNA-Seq]

Enhanced autophagy is recognized as a component of the pathogenesis of smoking-induced airway disease. Based on the knowledge that enhanced autophagy is linked to oxidative stress and the DNA damage response, both of which are linked to smoking, we used microarray analysis of the small airway epithelium to identify smoking up-regulated genes known to re-spond to oxidative stress and the DNA damage response. This analysis identified OSGIN1 as significantly up-regulated by smoking in both the large and small airway epithelium (1.8-fold, p<0.01, 2.1-fold, p<10-4, respectively), an observation confirmed by an independent small airway microarray cohort, TaqMan PCR and RNAseq. Genome-wide correlation of RNAseq analysis of airway basal/progenitor cells isolated from healthy subjects (n=17) showed a direct correlation of OSGIN1 mRNA levels to multiple classic autophagy genes, including, LC3B, P62, WIPI1 and ATG13 (all rho>0.7, p<0.01). In vitro cigarette smoke extract exposure of nonsmoker primary airway basal/progenitor cells was accompanied by a dose-dependent up-regulation of OSGIN1 and autophagy induction. Lentivirus-mediated enhanced expression of OSGIN1 in human primary basal/progenitor cells induced puncta-like staining of LC3B and up-regulation of LC3B mRNA and protein and P62 mRNA expression level in a dose and time-dependent manner. OSGIN1-induction of autophagosome / amphistome / autolysosome formation was confirmed by co-localization of LC3B with P62 or CD63 (endosome marker) and LAMP1 (lysosome marker). Induction of autophagy by OSGIN1 is accompanied with heightened oxidative stress. Together, these observations support the concept that smoking-induced up-regulation of OSGIN1 is at least one link between smoking-induced stress and enhanced-autophagy in the human airway epithelium. Overall design: Airway epithelium transcriptome analysis suggested that OSGIN, an oxidative response and cell death induction gene, was up-regulated by cigarette smoking and might be involved in autophagy regulation. In vitro study demonstrated that smoking can increase OSGIN1 expression and enhanced-expression of OSGIN1 led to autophagy, which is accompanied with heightened oxidative stress.

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Wang G, Zhou H, Strulovici-Barel Y, Al-Hijji M, Ou X, Salit J, Walters MS, Staudt MR, Kaner RJ, Crystal RG