A Peptide Encoded by lncRNA HOXB-AS3 Promotes Cigarette Smoke-Induced Inflammation in Bronchial Epithelial Cells via EZH2-Mediated H3K27me3 Modification.

Abstract

Background: Chronic obstructive pulmonary disease (COPD) primarily results from cigarette smoke (CS)-induced chronic inflammation. Although numerous long non-coding ribonucleic acids (lncRNAs) have been extensively studied for their crucial roles in COPD, the peptides encoded by these lncRNAs have garnered limited attention. This study aimed to investigate the role of a peptide encoded by lncRNA HOXB-AS3 in cigarette smoke extract (CSE)-induced inflammation and in 16HBE cells.

Methods: Open reading frames (ORF) Find software was utilized to predict the encoding potential of HOXB-AS3. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect the levels of peptide HOXB-AS3-32aa in peripheral blood mononuclear cells (PBMCs) from both healthy controls and COPD patients and in 16HBE cells exposed to different CSE. To establish an in vitro inflammatory cell model of COPD, 16HBE cells were treated with 2% CSE. Enzyme-Linked Immunosorbent Assay (ELISA) measured inflammatory cytokines, while CCK-8 assay assessed cell viability. Flow cytometry was employed to assess cell apoptosis. Western blot analysis was performed to measure the expression of HOXB-AS3-32aa, EZH2, and H3K27me3 proteins. Co-Immunoprecipitation (Co-IP) was conducted to verify the interaction between EZH2 and HOXB-AS3-32aa.

Results: Our findings revealed elevated expression of HOXB-AS3-32aa in PBMCs of COPD patients compared to controls. CSE treatment dose-dependently increased HOXB-AS3-32aa expression. Overexpression of HOXB-AS3-32aa exacerbated CS-induced inflammation in bronchial epithelial cells, leading to inhibited cell proliferation and increased cell apoptosis. Furthermore, HOXB-AS3-32aa suppressed EZH2 and H3k27me3 protein levels in 16HBE cells. Co-IP results confirmed the interaction between HOXB-AS3-32aa and EZH2 protein.

Conclusion: Our results demonstrate that the novel peptide HOXB-AS3-32aa encoded by lncRNA HOXB-AS3 promotes CS-induced inflammation and apoptosis in 16HBE cells via EZH2-mediated H3K27me3 modification.