Activation of ATM-c-IAP1 Pathway Mediates the Protective Effects of Estradiol in Human Vascular Endothelial Cells Exposed to Intermittent Hypoxia

Abstract

Purpose

Chronic intermittent hypoxia (CIH) contributes to the increased risk of cardiovascular diseases in obstructive sleep apnea (OSA). We previously reported the anti-apoptotic effects of estradiol (E2) on IH-exposed human umbilical vein endothelial cells (HUVECs). Herein, we employed a proteomic analysis to elucidate the mechanisms of the protective effects of E2 under IH exposure.

Methods

HUVECs were divided into three groups: control, IH, and IH+E2 group. Isobaric tags for relative and absolute quantification (iTRAQ) were performed to compare protein profiles among the groups. Some of the identified proteins were validated by Western blotting.

Results

A total of 185 proteins were differentially expressed in the IH+E2 group compared to the IH group. Bioinformatics analysis indicated that the effects of E2 may be linked to the regulation of cellular stress response. Among the differentially expressed proteins, we identified that serine-protein kinase ataxia telangiectasia mutated (ATM) and its downstream target, cellular inhibitor of apoptosis protein 1 (c-IAP1), were up-regulated by E2. We also observed that E2 decreased the level of cleaved caspase-3 and inhibited cell apoptosis in IH-exposed HUVECs. The inhibition of ATM abolished the anti-apoptotic effect of E2.

Conclusion

The ATM-c-IAP1 pathway is involved in the cardioprotective effects of E2 in HUVECs exposed to IH.

Keywords:

• estradiol
• obstructive sleep apnea
• OSA
• intermittent hypoxia
• IH
• endothelial dysfunction
• proteomics

Acknowledgments

This work was funded by the National Natural Science Foundation of China (81700084, 81070068, 81770084, 81570082, 81700085) and Shanghai Key Discipline for Respiratory Disease (2017ZZ02014), Key Research Program of Shanghai Science and Technology Commission (18140903600).

Disclosure

The authors report no conflicts of interest in this work.