Analysis of miRNA expression profile in lung tissues of an intermittent hypoxia rat model

https://doi.org/10.1016/j.resp.2021.103741Get rights and content

Highlights

  • There were different miRNA expression profiles in different intermittent hypoxia groups.

  • Some miRNAs were common in different intermittent hypoxia groups, and had excellent diagnostic value.

  • The LKB1/AMPK pathway and the S1P/Akt/eNOS pathway might play a role in the pathophysiological process of obstructive sleep apnea (OSA).

Abstract

We screened key miRNAs in an intermittent hypoxia rat model and explored the biological roles of downstream target genes and related regulatory pathways. We analyzed the expression profile of miRNAs in the lung tissues of rats in the 5 % (IH1), 7.5 % (IH2), 10 % (IH3), 12.5 % (IH4) oxygen concentration and negative control (NC) groups and identified common miRNAs. Multiple differentially expressed miRNAs were detected, and intersection of their expression profiles yielded 10 common miRNAs with 929 target genes mainly distributed in the nucleus. Molecular functions pertained mainly to the activation of transcription factors, while biological processes focused on cell interaction and signal transduction. Among signaling pathways, the top 5 included the LKB1 signaling, nectin adhesion, and S1P pathways. 8 of 10 common miRNAs had excellent diagnostic value for detecting intermittent hypoxia. The miRNAs binds to the target gene might play a key role in the pathophysiological process of OSA through the LKB1/AMPK and S1P/Akt/eNOS signaling pathways.

Introduction

Obstructive sleep apnea (OSA), the clinical features of which include snoring, apnea, and daytime sleepiness, is characterized by apnea and hypopnea disorder caused by the collapse of the upper airway during sleep (Lévy et al., 2015). In particular, OSA can be complicated by hypertension, diabetes, coronary heart disease, arrhythmia, cerebral apoplexy, cognitive dysfunction, and other chronic diseases (Jordan et al., 2014). Recent studies have revealed that OSA is related to the incidence and mortality of tumors (Nieto et al., 2012). The incidence rate of OSA has been reported to be 14 % and 5 % in American adult males and females, respectively (Peppard et al., 2013). Latest research has shown that currently 936 million adults aged between 30–69 years are suffering from OSA, with China having the highest prevalence of OSA worldwide (Benjafield et al., 2019).

Chronic intermittent hypoxia (CIH) is known to be the characteristic pathophysiological change associated with OSA. The process of hypoxia/reoxygenation, which is similar to ischemia/reperfusion injury, has been shown to produce excessive reactive oxygen species (ROS), resulting in the imbalance of oxidants and antioxidants in the body (Lavie, 2015; Lui et al., 2013). Moreover, ROS are known to activate the "inflammatory cascade", leading to the increased expression of pro-inflammatory cytokines and adhesion molecules (Pilkauskaite et al., 2013), which ultimately lead to systemic multi-organ function impairment.

MicroRNAs (miRNAs) are small non-coding RNAs (20−22‒nucleotide long) that bind to the 3′ untranslated regions (3′-UTR) of mRNAs to negatively regulate the expression of target genes (Bartoszewski and Sikorski, 2018). The expression of miRNAs has been closely related to lung growth and development, maintenance of pulmonary homeostasis, and pulmonary inflammation. Hypoxic conditions have been reported to induce expression changes in some miRNAs, which are thus called " hypoxic miRNAs " (Bertero et al., 2017). It has been reported that the altered expression of miRNAs plays a role in mediating the pathophysiological changes in diseases, suggesting the use of miRNAs as valuable tools for the diagnosis, treatment, and prognosis of these diseases (Luo et al., 2017; Yu et al., 2019).

In this study, we established rat models with different levels of intermittent hypoxia to simulate patients with varying severities of OSA, and used miRNA chip technology to detect the expression profile of miRNAs in rat lung tissues and explore the function of miRNAs in the context of OSA development.

Section snippets

Animal model

In our study, animal experiments complied with the ARRIVE guidelines and carried out in accordance with the U.K. Animals (Scientific Procedures) Act, 1986 and associated guidelines, EU Directive 2010/63/EU for animal experiments and Laboratory Animal Care and Use Standard of Kunming Medical University(Kunming, China). Animal experimental were approved by the Ethics Committee of Kunming Medical University. Briefly, 50 adult male Wistar rats (HFK Bioscience Co., LTD, Beijing, China), which with

Expressed miRNAs among different groups

We found that the expression of 47 miRNAs in the lung tissues of the IH1 group was significantly different (P < 0.05) compared with that of the control group. More specifically, 24 miRNAs were demonstrated to be upregulated, whereas 23 miRNAs were downregulated (Fig. 1A). A similar trend was observed in the lung tissues of the IH2 group (47 miRNAs, P < 0.05), in which 19 miRNAs were upregulated, whereas 28 miRNAs were downregulated (Fig. 1B). We also observed that 21 miRNAs were upregulated,

Discussion

Obstructive sleep apnea is a systemic disease of complex etiology. MiRNAs are important molecules, which regulate both the transcriptional and post-transcriptional processes, and play an important role in regulating cell growth, differentiation, stress, and apoptosis (Bartel, 2004). In this study, an miRNA microarray was used to screen the differentially expressed miRNAs in the lung tissues of different intermittent hypoxia groups and a negative control group.

We identified differences in the

Conclusions

In summary, we screened miRNAs in an intermittent hypoxia rat model and explored the biological roles of downstream target genes and related regulatory pathways. The aggravation of hypoxia corresponded with an altered expression profile of miRNAs. The expression profile of miRNAs in the lung tissues of rats exposed to different hypoxia levels identified certain common and differentially expressed miRNAs was detected. Some miRNAs had excellent diagnostic value for detecting OSA. The LKB1/AMPK

Author contributions

Zhijuan Liu: Conceptualization, Methodology, Formal analysis, Investigation, Writing - Original Draft, Writing - Review & Editing. Li Ai: Conceptualization, Methodology, Formal analysis, Investigation. Ran Li: Conceptualization, Methodology. Yuan Yang: Methodology, Formal analysis. Keli Chen: Methodology, Investigation. Chunxia He: Conceptualization, Methodology, Formal analysis. Yongxia Li: Conceptualization, Methodology, Writing - Review & Editing.

Funding

This work was supported by the National Natural Science Foundation of China (grant number: 81660019).

Data statement

All data, materials and software application support the published claims and comply with field standards.

Declaration of Competing Interest

The authors declare that they have no conflict of interest.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant number: 81660019).

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