Expression Profiles of circRNAs and Identification of hsa_circ_0007608 and hsa_circ_0064656 as Potential Biomarkers for COPD-PH Patients.

Abstract

Introduction: Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD), which can worsen the prognosis and increase the mortality of COPD patients. Circular RNA (circRNA) has been discovered to participate in the occurrence and progression of PH in COPD and may have significant prospects for advanced diagnostics and prognosis evaluation. However, the expression profile of circRNAs in human lung tissues with definite diagnosis of COPD-PH remains to be further explored and validated.

Methods: Twelve human lung tissue samples (6 each from COPD-PH and control groups) were collected and subjected to high-throughput sequencing. QRT-PCR was performed to validate the differential expression levels of the top 10 dysregulated circRNAs in patients' plasma samples, HPAECs and HPASMCs. Functional and pathway enrichment analysis on target genes was performed to explore the potential functions and pathways of those circRNAs. Hub genes obtained after conducting bioinformatics analysis on the predicted target mRNAs were verified by qRT-PCR in HPAECs and HPASMCs, and then we selected VCAN as a potential key gene involved in the pathogenesis of COPD-PH for immunohistochemistry validation in lung tissue.

Results: A total of 136 circRNAs (39 up-regulated and 97 down-regulated) were differentially expressed between the two groups. Following qRT-PCR validation, two circRNAs (hsa_circ_0007608 and hsa_circ_0064656) were believed to be involved in the pathogenesis. GO and KEGG pathway analysis suggested that these two DECs were mainly related to the celluar proliferation, migration and EndMT. PPI network revealed 11 pairs of key mRNAs. VCAM1, VCAN and THBS1, three hub mRNAs with the highest reliability among all, were validated and proven to be up-regulated in COPD-PH. We innovatively found that VCAN may be involved in COPD-PH.

Conclusion: This study identified the functional circRNAs, providing insights into the molecular mechanisms and predictions of COPD-PH, and may provide potential diagnostic biomarkers or therapeutic targets for COPD-PH.