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      MicroRNA-29a attenuates angiotensin-II induced-left ventricular remodeling by inhibiting collagen, TGF-β and SMAD2/3 expression

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          Abstract

          Background

          Left ventricular (LV) remodeling is the most common target organ damage in hypertension. Previously, our study found that plasma microRNA-29a (miR-29a) level was associated with the LV remodeling in hypertensive patients. However, the causal relationship between miR-29a and LV remodeling remains unknown. Thus, the aim of this study was to investigate the regulation mechanism of miR-29a in LV remodeling.

          Methods & Results

          Overexpression and knockdown miR-29a mice were generated by tail-intravenous injection of miR-29a-mimic and inhibitor lentivirus for one week respectively. Then the mice were subjected to angiotensin-II (AngII) induced LV remodeling by subcutaneous AngII capsule osmotic pumping into AngII for four weeks. AngII-induced LV remodeling mice as the model group ( n = 9). Age-matched male SPF C57/BL6J mice (6–8 weeks old) were treated with the pumping of saline as a vehicle ( n = 6). In vivo, overexpression miR-29a ameliorated AngII-induced LV remodeling, while knockdown miR-29a deteriorated LV remodeling. Simultaneously, we observed that overexpression miR-29a mice inhibited but knockdown miR-29a mice increased cardiac cross-sectional area, indicating that miR-29a has an antagonistic effect on cardiac hypertrophy. Further studies found that overexpression miR-29a inhibited the content of the LV collagen including collagen I and III. Moreover, the expression of transforming growth factor-β (TGF-β) and phosphorylated SMAD2/3 decreased with the down-regulation of collagen I and III in overexpression miR-29a mice.

          Conclusions

          Our finding indicates that overexpression miR-29a attenuates LV remodeling by inhibiting collagen deposition, TGF-β, and phosphorylated SMAD2/3 expression. Thus, intervention miR-29a may be a therapeutic target for attenuating LV remodeling.

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          Most cited references 28

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          Dysregulation of microRNAs after myocardial infarction reveals a role of miR-29 in cardiac fibrosis.

          Acute myocardial infarction (MI) due to coronary artery occlusion is accompanied by a pathological remodeling response that includes hypertrophic cardiac growth and fibrosis, which impair cardiac contractility. Previously, we showed that cardiac hypertrophy and heart failure are accompanied by characteristic changes in the expression of a collection of specific microRNAs (miRNAs), which act as negative regulators of gene expression. Here, we show that MI in mice and humans also results in the dysregulation of specific miRNAs, which are similar to but distinct from those involved in hypertrophy and heart failure. Among the MI-regulated miRNAs are members of the miR-29 family, which are down-regulated in the region of the heart adjacent to the infarct. The miR-29 family targets a cadre of mRNAs that encode proteins involved in fibrosis, including multiple collagens, fibrillins, and elastin. Thus, down-regulation of miR-29 would be predicted to derepress the expression of these mRNAs and enhance the fibrotic response. Indeed, down-regulation of miR-29 with anti-miRs in vitro and in vivo induces the expression of collagens, whereas over-expression of miR-29 in fibroblasts reduces collagen expression. We conclude that miR-29 acts as a regulator of cardiac fibrosis and represents a potential therapeutic target for tissue fibrosis in general.
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            Transforming growth factor beta in tissue fibrosis.

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              TGFbeta-SMAD signal transduction: molecular specificity and functional flexibility.

              Ligands of the transforming growth factor-beta (TGFbeta) superfamily of growth factors initiate signal transduction through a bewildering complexity of ligand-receptor interactions. Signalling then converges to nuclear accumulation of transcriptionally active SMAD complexes and gives rise to a plethora of specific functional responses in both embryos and adult organisms. Current research is focused on the mechanisms that regulate SMAD activity to evoke cell-type-specific and context-dependent transcriptional programmes. An equally important challenge is understanding the functional role of signal strength and duration. How are these quantitative aspects of the extracellular signal regulated? How are they then sensed and interpreted, and how do they affect responses?
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                Author and article information

                Journal
                J Geriatr Cardiol
                J Geriatr Cardiol
                JGC
                Journal of Geriatric Cardiology : JGC
                Science Press
                1671-5411
                February 2020
                : 17
                : 2
                : 96-104
                Affiliations
                [1 ]Department of Cardiology, Chinese People's Liberation Army General Hospital, Beijing, China
                [2 ]Department of Geriatric Cardiology, Chinese People's Liberation Army General Hospital, Beijing, China
                Author notes
                [*]

                The first two authors contributed equally to this manuscript.

                # Correspondence to: Yong-Yi BAI & Hao XUE, Department of Geriatric Cardiology, Chinese People's Liberation Army General Hospital, Beijing, China (BAI YY); Department of Cardiology, Chinese People's Liberation Army General Hospital, Beijing, China (XUE H). E-mails: baiyongy301@ 123456sina.com (BAI YY) & xuehaoxh301@ 123456163.com (XUE H)
                Article
                jgc-17-02-096
                10.11909/j.issn.1671-5411.2020.02.008
                7051875
                Institute of Geriatric Cardiology

                This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License, which allows readers to alter, transform, or build upon the article and then distribute the resulting work under the same or similar license to this one. The work must be attributed back to the original author and commercial use is not permitted without specific permission.

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