Duisters Rudy F, Tijsen Anke J, Schroen Blanche, Leenders Joost J, Lentink Viola, van der Made Ingeborg, Herias Veronica, van Leeuwen Rick E, Schellings Mark W, Barenbrug Paul, Maessen Jos G, Heymans Stephane, Pinto Yigal M, Creemers Esther E
Department of Cardiology, Cardiovascular Research Institute Maastricht, University of Maastricht, The Netherlands.
Circ Res. 2009 Jan 30;104(2):170-8, 6p following 178. doi: 10.1161/CIRCRESAHA.108.182535. Epub 2008 Dec 18.
The myocardium of the failing heart undergoes a number of structural alterations, most notably hypertrophy of cardiac myocytes and an increase in extracellular matrix proteins, often seen as primary fibrosis. Connective tissue growth factor (CTGF) is a key molecule in the process of fibrosis and therefore seems an attractive therapeutic target. Regulation of CTGF expression at the promoter level has been studied extensively, but it is unknown how CTGF transcripts are regulated at the posttranscriptional level. Here we provide several lines of evidence to show that CTGF is importantly regulated by 2 major cardiac microRNAs (miRNAs), miR-133 and miR-30. First, the expression of both miRNAs was inversely related to the amount of CTGF in 2 rodent models of heart disease and in human pathological left ventricular hypertrophy. Second, in cultured cardiomyocytes and fibroblasts, knockdown of these miRNAs increased CTGF levels. Third, overexpression of miR-133 or miR-30c decreased CTGF levels, which was accompanied by decreased production of collagens. Fourth, we show that CTGF is a direct target of these miRNAs, because they directly interact with the 3' untranslated region of CTGF. Taken together, our results indicate that miR-133 and miR-30 importantly limit the production of CTGF. We also provide evidence that the decrease of these 2 miRNAs in pathological left ventricular hypertrophy allows CTGF levels to increase, which contributes to collagen synthesis. In conclusion, our results show that both miR-133 and miR-30 directly downregulate CTGF, a key profibrotic protein, and thereby establish an important role for these miRNAs in the control of structural changes in the extracellular matrix of the myocardium.
衰竭心脏的心肌会发生一系列结构改变，最显著的是心肌细胞肥大和细胞外基质蛋白增加，常表现为原发性纤维化。结缔组织生长因子（CTGF）是纤维化过程中的关键分子，因此似乎是一个有吸引力的治疗靶点。人们已广泛研究了CTGF在启动子水平的表达调控，但尚不清楚CTGF转录本在转录后水平是如何调控的。在此，我们提供了几条证据表明，CTGF受两种主要的心脏微小RNA（miRNA），即miR-133和miR-30的重要调控。首先，在两种啮齿动物心脏病模型和人类病理性左心室肥大中，这两种miRNA的表达均与CTGF的量呈负相关。其次，在培养的心肌细胞和成纤维细胞中，敲低这些miRNA会增加CTGF水平。第三，miR-133或miR-30c的过表达会降低CTGF水平，同时胶原蛋白的产生也会减少。第四，我们证明CTGF是这些miRNA的直接靶点，因为它们直接与CTGF的3'非翻译区相互作用。综上所述，我们的结果表明miR-133和miR-30对限制CTGF的产生具有重要作用。我们还提供证据表明，在病理性左心室肥大中这两种miRNA的减少会使CTGF水平升高，从而促进胶原蛋白合成。总之，我们的结果表明，miR-133和miR-30均直接下调CTGF（一种关键的促纤维化蛋白），从而在控制心肌细胞外基质结构变化中发挥重要作用。
