Lymperopoulos Anastasios, Rengo Giuseppe, Zincarelli Carmela, Soltys Stephen, Koch Walter J
Center for Translational Medicine and George Zallie and Family Laboratory for Cardiovascular Gene Therapy, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Mol Ther. 2008 Feb;16(2):302-7. doi: 10.1038/sj.mt.6300371. Epub 2007 Nov 27.
We recently reported that the upregulation of adrenal G protein-coupled receptor kinase-2 (GRK2) causes enhanced catecholamine (CA) secretion by desensitizing sympatho-inhibitory alpha (2)-adrenergic receptors (alpha (2)ARs) of chromaffin cells, and thereby aggravating heart failure (HF). In this study, we sought to develop an efficient and reproducible in vivo adrenal gene transfer method to determine whether manipulation of adrenal GRK2 levels/activity regulates physiological CA secretion in rats. We specifically investigated two different in vivo gene delivery methods: direct injection into the suprarenal glands, and retrograde delivery through the suprarenal veins. We delivered adenoviral (Ad) vectors containing either GRK2 or an inhibitor of GRK2 activity, the beta ARKct. We found both delivery approaches equally effective at supporting robust (>80% of the whole organ) and adrenal-restricted transgene expression, in the cortical region as well as in the medullar region. Additionally, rats with AdGRK2-infected adrenals exhibit enhanced plasma CA levels when compared with control rats (AdGFP-injected adrenals), whereas plasma CA levels after Ad beta ARKct infection were significantly lower. Finally, in isolated chromaffin cells, alpha (2)ARs of AdGRK2-infected cells failed to inhibit CA secretion whereas Ad beta ARKct-infected cells showed normal alpha (2)AR responsiveness. These results not only indicate that in vivo adrenal gene transfer is an effective way of manipulating adrenal gland signalling, but also identify GRK2 as a critically important molecule involved in CA secretion.
我们最近报道，肾上腺G蛋白偶联受体激酶2（GRK2）的上调通过使嗜铬细胞的交感抑制性α（2）-肾上腺素能受体（α（2）ARs）脱敏，导致儿茶酚胺（CA）分泌增加，从而加重心力衰竭（HF）。在本研究中，我们试图开发一种高效且可重复的体内肾上腺基因转移方法，以确定操纵肾上腺GRK2水平/活性是否能调节大鼠的生理性CA分泌。我们特别研究了两种不同的体内基因递送方法：直接注射到肾上腺，以及通过肾上腺静脉逆行递送。我们递送了包含GRK2或GRK2活性抑制剂βARKct的腺病毒（Ad）载体。我们发现这两种递送方法在支持强大的（>整个器官的80%）和肾上腺限制性转基因表达方面同样有效，在皮质区域以及髓质区域均如此。此外，与对照大鼠（注射AdGFP的肾上腺）相比，感染AdGRK2的肾上腺的大鼠血浆CA水平升高，而感染AdβARKct后血浆CA水平显著降低。最后，在分离的嗜铬细胞中，感染AdGRK2的细胞的α（2）ARs未能抑制CA分泌，而感染AdβARKct的细胞显示出正常的α（2）AR反应性。这些结果不仅表明体内肾上腺基因转移是操纵肾上腺信号传导的有效方法，而且还确定GRK2是参与CA分泌的关键重要分子。
