Bittel Douglas C, Kibiryeva Nataliya, Marshall Jennifer A, O'Brien James E
Ward Family Heart Center, Children's Mercy Hospitals and Clinics and University of Missouri-Kansas City School of Medicine, 2401 Gillham Rd. Kansas City, MO 64108, USA.
Cells. 2014 Jul 11;3(3):713-23. doi: 10.3390/cells3030713.
The importance of microRNAs for maintaining stability in the developing vertebrate heart has recently become apparent. In addition, there is a growing appreciation for the significance of microRNAs in developmental pathology, including the formation of congenital heart defects. We examined the expression of microRNAs in right ventricular (RV) myocardium from infants with idiopathic tetralogy of Fallot (TOF, without a 22q11.2 deletion), and found 61 microRNAs to be significantly changed in expression in myocardium from children with TOF compared to normally developing comparison subjects (O'Brien et al. 2012). Predicted targets of microRNAs with altered expression were enriched for gene networks that regulate cardiac development. We previously derived a list of 229 genes known to be critical to heart development, and found 44 had significantly changed expression in TOF myocardium relative to normally developing myocardium. These 44 genes had significant negative correlations with 33 microRNAs, each of which also had significantly changed expression. Here, we focus on miR-421, as it is significantly upregulated in RV tissue from infants with TOF; is predicted to interact with multiple members of cardiovascular regulatory pathways; and has been shown to regulate cell proliferation. We knocked down, and over expressed miR-421 in primary cells derived from the RV of infants with TOF, and infants with normally developing hearts, respectively. We found a significant inverse correlation between the expression of miR-421 and SOX4, a key regulator of the Notch pathway, which has been shown to be important for the cardiac outflow track. These findings suggest that the dysregulation of miR-421 warrants further investigation as a potential contributor to tetralogy of Fallot.
微小RNA对于维持发育中的脊椎动物心脏稳定性的重要性近来已变得明显。此外，人们越来越认识到微小RNA在发育病理学中的重要性，包括先天性心脏缺陷的形成。我们检测了患有特发性法洛四联症（TOF，无22q11.2缺失）婴儿右心室（RV）心肌中微小RNA的表达，发现与正常发育的对照受试者相比，TOF患儿心肌中有61种微小RNA的表达发生了显著变化（奥布赖恩等人，2012年）。表达改变的微小RNA的预测靶标在调节心脏发育的基因网络中富集。我们之前得出了一份已知对心脏发育至关重要的229个基因的清单，发现其中44个基因在TOF心肌中的表达相对于正常发育的心肌有显著变化。这44个基因与33种微小RNA有显著的负相关，而这33种微小RNA的表达也都有显著变化。在此，我们聚焦于miR - 421，因为它在患有TOF的婴儿的RV组织中显著上调；预计会与心血管调节途径的多个成员相互作用；并且已被证明可调节细胞增殖。我们分别在来自患有TOF的婴儿和心脏正常发育的婴儿的RV的原代细胞中敲低并过表达了miR - 421。我们发现miR - 421的表达与SOX4之间存在显著的负相关，SOX4是Notch途径的关键调节因子，已被证明对心脏流出道很重要。这些发现表明，miR - 421的失调作为法洛四联症的一个潜在促成因素值得进一步研究。
