Xiaoxiong Xiao1, Tingwen Zhou2, Shichao Guo3, Chao Guo3, Qiao Zhang3, Nianguo Dong4, Yongjun Wang5. 1. Department of Cardiovascular Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China; Department of Thoracic Surgery, Xiangya Hospital, Central South University, Changsha 410008, Hunan Province, China. 2. Department of Cardiothoracic Surgery, University Hospital of Hubei University for Nationalities, Enshi 445000, Hubei Province, China. 3. Department of Cardiovascular Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China. 4. Department of Cardiovascular Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China. Electronic address: dongnianguodoc@hotmail.com. 5. Department of Cardiovascular Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China. Electronic address: wangyongjundoc@hotmail.com.
Abstract
BACKGROUND: Emerging evidences have indicated that long non-coding RNAs (lncRNAs) play vital roles in cardiovascular physiology and pathology. The lncRNA MALAT1, a highly abundant and conserved imprinted gene, has been implicated in many cardiovascular diseases. However, the function of MALAT1 in calcific aortic valve disease (CAVD) remains unknown. This study sought to document the function and underlying mechanism of MALAT1 in regulating CAVD. METHODS: Protein level was determined by immunoblotting and immunofluorescence staining. MALAT1, miR-204 and mRNA expressions were detected by qRT-PCR. Mineralized bone matrix formation was assessed by Alizarin Red staining. The interaction between MALAT1 and miR-204 was studied using luciferase reporter assay, RNA pull-down assay and RNA-binding protein immunoprecipitation assay. RESULTS: Ectopic expression of MALAT1 was observed in calcific valves and after osteogenic induction in human aortic valve interstitial cells (VICs). In vitro experiments revealed that MALAT1 acted as a positive regulator of osteogenic differentiation by repressing miR-204 expression and activity and thereby promoting expression of osteoblast-specific markers, including alkaline phosphatase, mineralized bone matrix formation and osteocalcin. Mechanistically, we identified Smad4 as a direct target of miR-204. Importantly, MALAT1 could directly interact with miR-204 and overexpression of miR-204 efficiently reversed the upregulation of Smad4 induced by MALAT1. Thus, MALAT1 positively regulated the expression of Smad4 through sponging miR-204, and promoted osteogenic differentiation of VICs. CONCLUSIONS: Our study provides novel mechanistic insights into a critical role for lncRNA MALAT1 as a miRNA sponge in CAVD and sheds new light on lncRNA-directed diagnostics and therapeutics in CAVD.
BACKGROUND: Emerging evidences have indicated that long non-coding RNAs (lncRNAs) play vital roles in cardiovascular physiology and pathology. The lncRNA MALAT1, a highly abundant and conserved imprinted gene, has been implicated in many cardiovascular diseases. However, the function of MALAT1 in calcific aortic valve disease (CAVD) remains unknown. This study sought to document the function and underlying mechanism of MALAT1 in regulating CAVD. METHODS: Protein level was determined by immunoblotting and immunofluorescence staining. MALAT1, miR-204 and mRNA expressions were detected by qRT-PCR. Mineralized bone matrix formation was assessed by Alizarin Red staining. The interaction between MALAT1 and miR-204 was studied using luciferase reporter assay, RNA pull-down assay and RNA-binding protein immunoprecipitation assay. RESULTS: Ectopic expression of MALAT1 was observed in calcific valves and after osteogenic induction in human aortic valve interstitial cells (VICs). In vitro experiments revealed that MALAT1 acted as a positive regulator of osteogenic differentiation by repressing miR-204 expression and activity and thereby promoting expression of osteoblast-specific markers, including alkaline phosphatase, mineralized bone matrix formation and osteocalcin. Mechanistically, we identified Smad4 as a direct target of miR-204. Importantly, MALAT1 could directly interact with miR-204 and overexpression of miR-204 efficiently reversed the upregulation of Smad4 induced by MALAT1. Thus, MALAT1 positively regulated the expression of Smad4 through sponging miR-204, and promoted osteogenic differentiation of VICs. CONCLUSIONS: Our study provides novel mechanistic insights into a critical role for lncRNA MALAT1 as a miRNA sponge in CAVD and sheds new light on lncRNA-directed diagnostics and therapeutics in CAVD.
Authors: Anja M Billing; Shaima S Dib; Aditya M Bhagwat; Israel T da Silva; Rodrigo D Drummond; Shahina Hayat; Rasha Al-Mismar; Hisham Ben-Hamidane; Neha Goswami; Kasper Engholm-Keller; Martin R Larsen; Karsten Suhre; Arash Rafii; Johannes Graumann Journal: Mol Cell Proteomics Date: 2019-07-22 Impact factor: 5.911
Authors: Huachun Cui; Sami Banerjee; Sijia Guo; Na Xie; Jing Ge; Dingyuan Jiang; Martin Zörnig; Victor J Thannickal; Gang Liu Journal: JCI Insight Date: 2019-02-21