1. Downregulation of microRNA-199a-5p protects cardiomyocytes in cyanotic congenital heart disease by attenuating endoplasmic reticulum stress
- Author
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Ying‑Bin Xiao, Wei‑Kun Jia, Yong Wang, Liang Zhao, Chen‑Cheng Liu, Zhao Jian, and Yang Zhou
- Subjects
0301 basic medicine ,Cancer Research ,medicine.medical_specialty ,Adolescent ,Heart Diseases ,Activating transcription factor ,Down-Regulation ,Apoptosis ,Biology ,Biochemistry ,03 medical and health sciences ,Downregulation and upregulation ,Internal medicine ,Genetics ,medicine ,Humans ,Myocyte ,Myocytes, Cardiac ,Child ,Endoplasmic Reticulum Chaperone BiP ,Molecular Biology ,Cells, Cultured ,Heat-Shock Proteins ,Cyanosis ,Oncogene ,ATF6 ,Myocardium ,Endoplasmic reticulum ,Hypoxia (medical) ,Endoplasmic Reticulum Stress ,Cell Hypoxia ,Activating Transcription Factor 6 ,Cell biology ,MicroRNAs ,030104 developmental biology ,Endocrinology ,Oncology ,Child, Preschool ,Unfolded Protein Response ,Unfolded protein response ,Molecular Medicine ,medicine.symptom - Abstract
Chronic hypoxia is a key pathological change in patients with cyanotic congenital heart defect (CCHD). It has been demonstrated that enhanced myocardial unfolded protein response (UPR) increases the capacity to buffer endoplasmic reticulum (ER) stress and to avoid subsequent apoptosis caused by the hypoxia that underlies CCHD. The present study was performed to determine the regulatory role of microRNAs (miRNAs) in this cytoprotective UPR process. The results revealed that miR‑199a‑5p was markedly downregulated in the cardiac tissue of patients with CCHD and in human myocardial cells cultured in hypoxic conditions. The two major UPR modulators, 78 kDa glucose‑regulated protein (GRP78) and activating transcription factor 6 (ATF6), were potential target genes of miR‑199a‑5p in CCHD myocardial specimens. In addition, the miR‑199a‑5p mimic and inhibitor were evidently able to change GRP78 and ATF6 gene expression and ER stress‑associated apoptosis in hypoxia‑treated cardiomyocytes. The interaction between miR‑199a‑5p and the ATF6 and GRP78 3'‑UTR binding sites in myocardial cells was also confirmed by luciferase assay. Thus, it is concluded that myocardial downregulation of miR‑199a‑5p favors the UPR against hypoxia‑induced ER stress in CCHD, which contributes to myocardial protection.
- Published
- 2017