title: Micro-RNA 21Targets dual specific phosphatase 8 to promote collagen synthesis in high glucose-treated primary cardiac fibroblasts.
abstract: BACKGROUND
  Micro-RNA 21 (miR-21) has been shown to contribute to cardiac fibrosis in many diseases. In this study we investigated the role of miR-21 in excessive production of collagen in diabetic cardiomyopathy.
  
  
  METHODS
  The proliferation rate of cardiac fibroblasts was analyzed by Western blot, Cell Counting Kit-8 kit (Dojindo Molecular Technologies, Kumamoto, Japan), and Cell-Light EdU Apollo 488 In Vitro Imaging Kit (RiboBio, Guangzhou, China). Real-time polymerase chain reaction and Western blotting were conducted to determine gene expression levels. A luciferase reporter assay was used to verify the interaction between miR-21 and the 3' untranslated region (3'UTR) of dual specific phosphatase 8 (DUSP8).
  
  
  RESULTS
  Our results show that high glucose promoted the proliferation and collagen synthesis of rat cardiac fibroblasts, which was accompanied by an increase of miR-21. Gain-of-function and loss-of-function assays confirmed that miR-21 mediated this effect, suggesting the crucial role of miR-21 in diabetic cardiomyopathy. Our study also identified a direct target of miR-21, DUSP8, which regulates cell proliferation and collagen synthesis in cardiac fibroblasts through p38 and c-Jun N-terminal kinase (JNK)/stress-activated kinase (SAPK) signalling. Our results show that miR-21 bound to the 3'UTR of DUSP8 post-transcriptionally repressed its expression. In addition, enforced expression of miR-21 activated the JNK/SAPK and p38 signalling pathways.
  
  
  CONCLUSIONS
  Our study shows that miR-21 promotes high glucose-induced cardiac fibrosis through the JNK/SAPK and p38 signalling pathways by suppressing DUSP8 expression.
authors.affiliation: Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shulei
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Mingtong
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Zengcheng People's Hospital, Guangzhou, China. Electronic address: chenxch@mail.sysu.edu.cn.
authors.forename: Xiaochao
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D003921:Diabetes Mellitus, Experimental; D058065:Diabetic Cardiomyopathies / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005947:Glucose / Q000494:pharmacology*; D035683:MicroRNAs / Q000235:genetics*; D032342:Muscle Cells / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs; D003094:Collagen; D005947:Glucose