PIF1 Promotes Autophagy to Inhibit Chronic Hypoxia Induced Apoptosis of Pulmonary Artery Endothelial Cells

Abstract

Purpose

Pulmonary artery hypertension (PAH) is a common complication of chronic obstructive pulmonary disease and obstructive sleep apnea/hypopnea syndrome worldwide. Pulmonary vascular alterations associated with PAH have multifactorial causes, in which endothelial cells play an important role. Autophagy is closely related to endothelial cell injury and the development of PAH. PIF1 is a multifunctional helicase crucial for cell survival. The present study investigated the effect of PIF1 on autophagy and apoptosis in human pulmonary artery endothelial cells (HPAECs) under chronic hypoxia stress.

Methods

Chronic hypoxia Gene expression profiling chip-assays identified the PIF1 gene as differentially expressed, which was verified by RT-qPCR analysis. Electron microscopy, immunofluorescence, and Western blotting were used to analyze autophagy and the expression of LC3 and P62. Apoptosis was analyzed using flow cytometry.

Results

Our study found that chronic hypoxia induces autophagy in HPAECs, and apoptosis was exacerbated by inhibiting autophagy. Levels of the DNA helicase PIF1 were increased in HPAECs after chronic hypoxia. PIF1 knockdown inhibited autophagy and promoted the apoptosis of HPAECs under chronic hypoxia stress.

Conclusion

Based on these findings, we conclude that PIF1 inhibits the apoptosis of HPAECs by accelerating the autophagy pathway. Therefore, PIF1 plays a crucial role in HPAEC dysfunction in chronic hypoxia-induced PAH and may be a potential target for the treatment of PAH.

Keywords:

• PIF1
• autophagy
• HPAEC
• PAH
• chronic hypoxia

Data Sharing Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethics Approval and Consent to Participate

This study did not require approval from the Ethical and Informed Consent Committee because only involved cells.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (no. 32200168), the Basic Research Project of Natural Science in Shanxi Province (no. 20210302124039), the Key Research and Development Program in Shanxi Province (no.201803D31093), and the Start-up Foundation for Doctoral Scientific Research of Shanxi Medical University (No. XD1905).