Autophagy impairment in patients with obstructive sleep apnea modulates intermittent hypoxia-induced oxidative stress and cell apoptosis via hypermethylation of the ATG5 gene promoter region

Yung-Che Chen; I-Chun Lin; Mao-Chang Su; Po-Yuan Hsu; Chang-Chun Hsiao; Te-Yao Hsu; Chia-Wei Liou; Yu-Mu Chen; Chien-Hung Chin; Ting-Ya Wang; Jen-Chieh Chang; Yong-Yong Lin; Chiu-Ping Lee; Meng-Chih Lin

doi:10.1186/s40001-023-01051-4

Autophagy impairment in patients with obstructive sleep apnea modulates intermittent hypoxia-induced oxidative stress and cell apoptosis via hypermethylation of the ATG5 gene promoter region

Eur J Med Res. 2023 Feb 17;28(1):82. doi: 10.1186/s40001-023-01051-4.

Authors

Yung-Che Chen^{1

2

3}, I-Chun Lin⁴, Mao-Chang Su^{5

6

7}, Po-Yuan Hsu⁵, Chang-Chun Hsiao^{5

8}, Te-Yao Hsu⁹, Chia-Wei Liou¹⁰, Yu-Mu Chen^{5

6}, Chien-Hung Chin^{5

6}, Ting-Ya Wang⁵, Jen-Chieh Chang¹¹, Yong-Yong Lin⁵, Chiu-Ping Lee⁵, Meng-Chih Lin^{12

13

14}

Affiliations

¹ Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan. yungchechen@yahoo.com.tw.
² Department of Medicine, College of Medicine, Chang Gung University, Taouyan, 33302, Taiwan. yungchechen@yahoo.com.tw.
³ Sleep Center, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan. yungchechen@yahoo.com.tw.
⁴ Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan.
⁵ Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan.
⁶ Sleep Center, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan.
⁷ Chang Gung University of Science and Technology, Chiayi, 61363, Taiwan.
⁸ Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taouyan, 33302, Taiwan.
⁹ Department of Obstetrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan.
¹⁰ Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan.
¹¹ Genomics and Proteomics Core Lab, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301, Taiwan.
¹² Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan. linmengchih@hotmail.com.
¹³ Department of Medicine, College of Medicine, Chang Gung University, Taouyan, 33302, Taiwan. linmengchih@hotmail.com.
¹⁴ Sleep Center, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Rd, Niao-Sung District, Kaohsiung, 83301, Taiwan. linmengchih@hotmail.com.

Abstract

Background: Autophagy is a catabolic process that recycles damaged organelles and acts as a pro-survival mechanism, but little is known about autophagy dysfunction and epigenetic regulation in patients with obstructive sleep apnea (OSA).

Methods: Protein/gene expressions and DNA methylation levels of the autophagy-related genes (ATG) were examined in blood leukocytes from 64 patients with treatment-naïve OSA and 24 subjects with primary snoring (PS).

Results: LC3B protein expression of blood monocytes, and ATG5 protein expression of blood neutrophils were decreased in OSA patients versus PS subjects, while p62 protein expression of cytotoxic T cell was increased, particularly in those with nocturia. ATG5, ULK1, and BECN1 gene expressions of peripheral blood mononuclear cells were decreased in OSA patients versus PS subjects. LC3B gene promoter regions were hypermethylated in OSA patients, particularly in those with excessive daytime sleepiness, while ATG5 gene promoter regions were hypermethylated in those with morning headache or memory impairment. LC3B protein expression of blood monocytes and DNA methylation levels of the LC3B gene promoter region were negatively and positively correlated with apnea hyponea index, respectively. In vitro intermittent hypoxia with re-oxygenation exposure to human THP-1/HUVEC cell lines resulted in LC3B/ATG5/ULK1/BECN1 down-regulations and p62 up-regulation along with increased apoptosis and oxidative stress, while rapamycin and umbilical cord-mesenchymal stem cell treatment reversed these abnormalities through de-methylation of the ATG5 gene promoter.

Conclusions: Impaired autophagy activity in OSA patients was regulated by aberrant DNA methylation, correlated with clinical phenotypes, and contributed to increased cell apoptosis and oxidative stress. Autophagy enhancers may be novel therapeutics for OSA-related neurocognitive dysfunction.

Keywords: Autophagy; DNA methylation; Intermittent hypoxia with re-oxygenation; Mesenchymal stem cell; Obstructive sleep apnea; Rapamycin.

MeSH terms

Apoptosis / genetics
Autophagy / genetics
Autophagy-Related Protein 5 / genetics
DNA Methylation* / genetics
Epigenesis, Genetic*
Humans
Leukocytes, Mononuclear
Oxidative Stress / genetics

Substances

ATG5 protein, human
Autophagy-Related Protein 5

Grants and funding

NMRPG8F6071-6073/105-2314-B-182A-092-MY3/NMRPG8J6131-6133/108-2314-B- 182A-129-MY3/Ministry of Science and Technology, Taiwan