miR-21 is upregulated, promoting fibrosis and blocking G2/M in irradiated rat cardiac fibroblasts

Huan Guo; Xinke Zhao; Haixiang Su; Chengxu Ma; Kai Liu; Shanshan Kong; Kedan Liu; Haining Li; Juan Chang; Tao Wang; Hongyun Guo; Huiping Wei; Zhaoyuan Fu; Xinfang Lv; Yingdong Li

doi:10.7717/peerj.10502

miR-21 is upregulated, promoting fibrosis and blocking G2/M in irradiated rat cardiac fibroblasts

PeerJ. 2020 Dec 10:8:e10502. doi: 10.7717/peerj.10502. eCollection 2020.

Authors

Huan Guo^{1

2

3}, Xinke Zhao^{4

5}, Haixiang Su³, Chengxu Ma⁶, Kai Liu², Shanshan Kong², Kedan Liu³, Haining Li³, Juan Chang², Tao Wang³, Hongyun Guo³, Huiping Wei⁴, Zhaoyuan Fu⁴, Xinfang Lv³, Yingdong Li^{1

2}

Affiliations

¹ School of Basic Medical Sciences, Lan Zhou University, Lan Zhou, Gan Su, China.
² Gansu University of Chinese Medicine, Lan Zhou, Gan Su, China.
³ Gansu Provincial Academic Institute for Medical Sciences, Gansu Provincial Cancer Hospital, Lan Zhou, Gan Su, China.
⁴ Department of Interventional Section, Affiliated Hospital of Gansu University of Chinese Medicine, Lan Zhou, Gan Su, China.
⁵ Chinese Academy of Medical Sciences, Fuwai Hospital, Bei Jing, China.
⁶ Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu, China.

Abstract

Background: Radiation exposure of the thorax is associated with a greatly increased risk of cardiac morbidity and mortality even after several decades of advancement in the field. Although many studies have demonstrated the damaging influence of ionizing radiation on cardiac fibroblast (CF) structure and function, myocardial fibrosis, the molecular mechanism behind this damage is not well understood. miR-21, a small microRNA, promotes the activation of CFs, leading to cardiac fibrosis. miR-21 is overexpressed after irradiation; however, the relationship between increased miR-21 and myocardial fibrosis after irradiation is unclear. This study was conducted to investigate gene expression after radiation-induced CF damage and the role of miR-21 in this process in rats.

Methods: We sequenced irradiated rat CFs and performed weighted correlation network analysis (WGCNA) combined with differentially expressed gene (DEG) analysis to observe the effect on the expression profile of CF genes after radiation.

Results: DEG analysis showed that the degree of gene changes increased with the radiation dose. WGCNA revealed three module eigengenes (MEs) associated with 8.5-Gy-radiation-the Yellow, Brown, Blue modules. The three module eigengenes were related to apoptosis, G2/M phase, and cell death and S phase, respectively. By blocking with the cardiac fibrosis miRNA miR-21, we found that miR-21 was associated with G2/M blockade in the cell cycle and was mainly involved in regulating extracellular matrix-related genes, including Grem1, Clu, Gdf15, Ccl7, and Cxcl1. Stem-loop quantitative real-time PCR was performed to verify the expression of these genes. Five genes showed higher expression after 8.5 Gy-radiation in CFs. The target genes of miR-21 predicted online were Gdf15 and Rsad2, which showed much higher expression after treatment with antagomir-miR-21 in 8.5-Gy-irradiated CFs. Thus, miR-21 may play the role of fibrosis and G2/M blockade in regulating Grem1, Clu, Gdf15, Ccl7, Cxcl1, and Rsad2 post-irradiation.

Keywords: CFs; Cell cycle; Fibrosis; Heart; WGCNA and DEG; X-ray.

Grants and funding

This work was supported by the National Natural Science Foundation of China [grant numbers: 81760798, 81873132, (Yingdong Li) and 81860786 (Xin Ke Zhao)]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.