Ernault Auriane C, Kawasaki Makiri, Fabrizi Benedetta, Montañés-Agudo Pablo, Amersfoorth Shirley C M, Al-Shama Rushd F M, Coronel Ruben, De Groot Joris R
Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.
Front Physiol. 2022 Nov 17;13:1057200. doi: 10.3389/fphys.2022.1057200. eCollection 2022.
Atrial fibrosis plays an important role in the development and persistence of atrial fibrillation by promoting reentry. Primary cilia have been identified as a regulator of fibroblasts (FB) activation and extracellular matrix (ECM) deposition. We hypothesized that selective reduction of primary cilia causes increased fibrosis and facilitates reentry. The aim of this study was to disrupt the formation of primary cilia in FB and examine its consequences on ECM and conduction in a co-culture system of cardiomyocytes (CM) and FB. Using short interfering RNA (siRNA), we removed primary cilia in neonatal rat ventricular FB by reducing the expression of gene required for ciliary assembly. We co-cultured neonatal rat ventricular cardiomyocytes (CM) with FB previously transfected with siRNA (siIft88) or negative control siRNA (siNC) for 48 h. We examined the consequences of ciliated fibroblasts reduction on conduction and tissue remodeling by performing electrical mapping, microelectrode, and gene expression measurements. Transfection of FB with siIft88 resulted in a significant 60% and 30% reduction of relative expression in FB and CM-FB co-cultures, respectively, compared to siNC. Knockdown of significantly increased the expression of ECM genes , and by 38%, 30% and 18%, respectively, in comparison to transfection with siNC. Conduction velocity (CV) was significantly decreased in the siIft88 group in comparison to siNC [11.12 ± 4.27 cm/s ( = 10) vs. 17.00 ± 6.20 ( = 10) respectively, < 0.05]. The fraction of sites with interelectrode activation block was larger in the siIft88 group than in the siNC group (6.59 × 10 ± 8.01 × 10 vs. 1.18 × 10 ± 3.72 × 10 respectively, < 0.05). We documented spontaneous reentrant arrhythmias in two cultures in the siIft88 group and in none of the siNC group. Action potentials were not significantly different between siNC and siIft88 groups. Disruption of cilia formation by siIft88 causes ECM remodeling and conduction abnormalities. Prevention of cilia loss could be a target for prevention of arrhythmias.
心房纤维化通过促进折返在心房颤动的发生和持续中起重要作用。原发性纤毛已被确定为成纤维细胞（FB）激活和细胞外基质（ECM）沉积的调节因子。我们假设原发性纤毛的选择性减少会导致纤维化增加并促进折返。本研究的目的是破坏FB中原发性纤毛的形成，并在心肌细胞（CM）和FB的共培养系统中检查其对ECM和传导的影响。使用小干扰RNA（siRNA），我们通过降低纤毛组装所需基因的表达来去除新生大鼠心室FB中的原发性纤毛。我们将新生大鼠心室心肌细胞（CM）与先前用siRNA（siIft88）或阴性对照siRNA（siNC）转染的FB共培养48小时。我们通过进行电图、微电极和基因表达测量来检查纤毛化成纤维细胞减少对传导和组织重塑的影响。与siNC相比，用siIft88转染FB导致FB和CM-FB共培养物中相对表达分别显著降低60%和30%。与用siNC转染相比，敲低显著使ECM基因、和的表达分别增加38%、30%和18%。与siNC相比，siIft88组的传导速度（CV）显著降低[分别为11.12±4.27cm/s（n = 10）和17.00±6.20（n = 10），P < 0.05]。siIft88组电极间激活阻滞部位的比例大于siNC组（分别为6.59×10±8.01×10和1.18×10±3.72×10，P < 0.05）。我们在siIft88组的两个培养物中记录到自发性折返性心律失常，而siNC组均未记录到。siNC组和siIft88组之间的动作电位无显著差异。siIft88破坏纤毛形成会导致ECM重塑和传导异常。预防纤毛丢失可能是预防心律失常的一个靶点。
