Enhancement of murine cardiac chronotropy by the molecular transfer of the human β2 adrenergic receptor cDNA
Enhancement of murine cardiac chronotropy by the molecular transfer of the human β2 adrenergic receptor cDNA
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DOI：
10.1172/jci1330
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发表时间：
1998-01-15
影响因子：
15.9
通讯作者：
Rosenberg, RD
中科院分区：
文献类型：
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作者：
Edelberg, JM;Aird, WC;Rosenberg, RD
心脏起搏为将基因直接转移到心脏提供了独特的机会。开发了一个实验系统来测定在体外、离体和最终体内条件下转移人 β(2) 肾上腺素能受体 (β(2)AR) 的效果。编码 β(2)AR 或 LacZ 的构建体用于分离的肌细胞的变时性研究，并移植以及内源性小鼠心脏。用质粒构建体瞬时转染小鼠胚胎心肌细胞。与对照细胞相比，β(2)AR 转染细胞中肌细胞自发收缩的总百分比更高（67% vs. 42 +/- 5%）。此外，与对照细胞相比，β(2)AR 群体中变时率 > 60 次/分钟 (bpm) 的肌细胞百分比较高（37% vs. 15+/-5%）。基线时，β(2)AR 转染的肌细胞的平均收缩率更高（71+/-14 与 50+/-10 bpm；P < 0.001），以及添加 10(-3) M 异丙肾上腺素后（98+/-26 与 75+/-18 bpm；P < 0.05）。基于这些结果，使用小鼠新生儿心脏移植模型来研究β(2)AR靶向表达的离体效应。将构建体转染到移植心脏的右心房中。注射 beta(2)AR 构建体可使心率增加约 40%（224+/-37 与 161+/-42 bpm；P < 0.005）。最后，将构建体注射到内源性心脏的右心房进行体内测试。这些结果与注射 β(2)AR 构建体的离体数据相似，与对照注射的心脏相比，内源性心率增加了约 40%（550+/-42 与 390+/-37 bpm；P < 0.05）。这些研究表明，基因表达的局部靶向可能是调节心脏起搏活动的可行方式。
Cardiac pacemaking offers a unique opportunity for direct gene transfer into the heart. An experimental system was developed to assay the effects of transferring the human beta(2) adrenergic receptor (beta(2)AR) under in vitro, ex vivo, and finally in vivo conditions. Constructs encoding either beta(2)AR or LacZ were used in chronotropy studies with isolated myocytes, and transplanted as well as endogenous murine hearts. Murine embryonic cardiac myocytes were transiently transfected with plasmid constructs. The total percentage of myocytes spontaneously contracting was greater in beta(2)AR transfected cells, as compared with control cells (67 vs. 42 +/- 5%). In addition, the percentage of myocytes with chronotropic rates > 60 beats per minute (bpm) was higher in the beta(2)AR population, as compared with control cells (37 vs. 15+/-5%). The average contractile rate was greater in the beta(2)AR transfected myocytes at baseline (71+/-14 vs. 50+/-10 bpm; P < 0.001) as well as with the addition of 10(-3) M isoproterenol (98+/-26 vs. 75+/-18 bpm; P < 0.05). Based on these results, a murine neonatal cardiac transplantation model was used to study the ex vivo effects of targeted expression of beta(2)AR. The constructs were transfected into the right atrium of transplanted hearts. Injection of the beta(2)AR construct increased the heart rate by similar to 40% (224+/-37 vs. 161+/-42 bpm; P < 0.005). Finally, the constructs were tested in vivo with injection into the right atrium of the endogenous heart, These results were similar to the ex vivo data with injection of the beta(2)AR constructs increasing the endogenous heart rates by similar to 40%, as compared with control injected hearts (550+/-42 vs. 390+/-37 bpm; P < 0.05). These studies demonstrate that local targeting of gene expression may be a feasible modality to regulate the cardiac pacemaking activity.