Background
Pulmonary small airway epithelia are the primary site of cellular and histological alterations in chronic obstructive pulmonary disease (COPD), while the potential therapeutic hub genes of pulmonary epithelia are rarely identified to elucidate profound alterations in the progression of the disease.
Methods
Microarray dataset of GSE11906 containing small airway epithelia from 34 healthy non-smokers and 33 COPD patients was applied to screen differentially expressed genes (DEGs). Weighted gene correlation network analysis (WGCNA) was further used to identify the hub genes related to clinical features. Moreover, single-cell RNA sequencing data from GSE173896 and GSE167295 dataset were applied to explore the expression and distribution of the hub genes. The expression levels of hub genes in epithelial cells stimulated by cigarette smoke extract (CSE) were detected by RT-qPCR.
Results
Ninety-eight DEGs correlated with clinical features of COPD were identified via limma and WGCNA. Eight hub genes (including
AKR1C3
,
ALDH3A1
,
AKR1C1
,
CYP1A1
,
GPX2
,
CBR3
,
AKR1B1
and
GSR
) that might exert an antioxidant role in COPD process were identified. Single-cell transcriptomic analysis indicated that the expressions of
AKRAC3
,
ALDH3A1
,
GPX2
,
CBR3
and
AKR1B1
were significantly increased in the COPD group when compared with the normal group. Moreover, we found that the expression of
ALDH3A1
was the most abundantly expressed in ciliated cells. RT-qPCR results indicated that the majority of candidate novel genes were significantly elevated when the epithelial cells were exposed to CSE.
Conclusion
Through integrating limma, WGCNA, and protein-protein interaction (PPI) analysis, a total of eight candidate hub genes of pulmonary airway epithelia were identified in COPD. Moreover, single-cell transcriptomic analysis indicated that
ALDH3A1
was enriched in ciliated cells, which may provide a new insight into the pathogenesis and treatment of COPD.