Cross‐regulation between β1‐ and β3‐adrenoceptors following chronic β‐adrenergic stimulation in neonatal rat cardiomyocytes
Cross‐regulation between β1‐ and β3‐adrenoceptors following chronic β‐adrenergic stimulation in neonatal rat cardiomyocytes
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发表时间：
2009
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通讯作者：
C. Ufer;R. Germack
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作者：
C. Ufer;R. Germack
背景和目的：我们以前已经表明，持续刺激去甲肾上腺素β-肾上腺素受体诱导增加β 3-肾上腺素受体（GaiPCR）和减少β 1-肾上腺素受体（GasPCR）在功能，基因组和蛋白质水平。去甲肾上腺素引起的这种代偿性改变可能是心脏病中观察到的心脏抑制的后果之一。因此，我们进一步研究了新生大鼠心肌细胞中b1和b3肾上腺素受体之间的相互作用。实验方法：在存在或不存在蛋白激酶抑制剂的情况下，通过未处理或用多巴酚丁胺和ICI 118551（b1-肾上腺素受体）或CL-3162436243（b3-肾上腺素受体）处理24 h的细胞中的环磷酸腺苷（cAMP）蓄积试验进行功能研究。β-肾上腺素受体和蛋白激酶的表达分别通过定量逆转录-聚合酶链反应（RT-PCR）和Western印迹法进行监测。主要成果：慢性刺激b1或b3肾上腺素受体可通过蛋白激酶C（PKC）、磷酸肌醇3激酶（PI 3 K）和p38丝裂原活化蛋白激酶（p38 MAPK）激活减少b1肾上腺素受体介导的cAMP蓄积，并降低b1肾上腺素受体mRNA和蛋白水平。与此相反，两种治疗诱导增加b3-肾上腺素能受体的表达和b3-肾上腺素能受体抑制毛喉素反应通过PKC，细胞外信号调节激酶1和2（ERK 1/2）和p38 MAPK磷酸化，虽然没有b3-肾上腺素能受体反应在未处理的细胞中观察到。ERK 1/2和p38 MAPK被两种处理激活。虽然慢性刺激b1肾上腺素受体激活了SAPK/JNK，但b1或b3肾上腺素受体功能的调节不需要应激激活蛋白激酶/c-Jun N-末端激酶（SAPK/JNK）。β 3-肾上腺素能受体处理激活Akt，尽管PI 3 K不参与β 3-肾上腺素能受体上调。结论和影响：我们首次发现，慢性刺激b1或b3肾上腺素受体可通过PKC、PI 3 K p38 MAPK和MEK/ERK 1/2通路的交叉调节，以及通过蛋白激酶A对b1和b3肾上腺素受体的调节。英国药理学杂志（2009）158，300-313; doi：10.1111/j.1476-5381.2009.00328.x
Background and purpose: We have previously shown that b-adrenoceptors continuously stimulated with noradrenaline induces an increase in b3-adrenoceptors (GaiPCRs) and a decrease in b1-adrenoceptors (GasPCRs) at functional, genomic and protein levels. This compensatory modification induced by noradrenaline is probably one of the consequences of cardiac depression observed in heart disease. Therefore, we investigated further the interaction between b1and b3-adrenoceptors in neonatal rat cardiomyocytes. Experimental approach: Functional studies were performed by cyclic adenosine monophosphate (cAMP) accumulation assays in cells untreated or treated with dobutamine and ICI 118551 (b1-adrenoceptor) or CL-3162436243 (b3-adrenoceptor) for 24 h in the presence or absence of protein kinase inhibitors. b-adrenoceptor and protein kinase expression was monitored by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and by Western blotting, respectively. Key results: Chronic b1or b3-adrenoceptor stimulation reduced b1-adrenoceptor-mediated cAMP accumulation in association with a decrease in b1-adrenoceptor mRNA and protein levels through protein kinase C (PKC), phosphoinositide 3-kinase (PI3K) and p38 mitogen-activated protein kinase (p38MAPK) activation. In contrast, both treatments induced an increase in b3-adrenoceptor expression and b3-adrenoceptor-inhibited forskolin response through PKC, extracellular-signal-regulated kinases 1 and 2 (ERK1/2) and p38MAPK phosphorylation, although no b3-adrenoceptor response was observed in untreated cells. ERK1/2 and p38MAPK were activated by both treatments. The modulation of b1or b3-adrenoceptor function did not require stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) although chronic b1-adrenoceptor stimulation activated SAPK/JNK. b3-adrenoceptor treatment activated Akt although PI3K was not involved in b3-adrenoceptor up-regulation. Conclusion and implications: We show for the first time that chronic b1or b3-adrenoceptor stimulation leads to the modulation of b1and b3-adrenoceptors by a cross-regulation involving PKC, PI3K p38MAPK and MEK/ERK1/2 pathway, and through protein kinase A when b1-adrenoceptors are chronically activated. British Journal of Pharmacology (2009) 158, 300–313; doi:10.1111/j.1476-5381.2009.00328.x