Exogenous and endogenous adenosine inhibits fetal calf serum-induced growth of rat cardiac fibroblasts - Role of A(2B) receptors
Exogenous and endogenous adenosine inhibits fetal calf serum-induced growth of rat cardiac fibroblasts - Role of A(2B) receptors
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DOI：
10.1161/01.cir.96.8.2656
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发表时间：
1997-10-21
期刊：
影响因子：
37.8
通讯作者：
Jackson, EK
中科院分区：
文献类型：
--
作者：
Dubey, RK;Gillespie, DG;Jackson, EK
由于心脏成纤维细胞的增殖参与了高血压和心肌梗死相关的心脏肥大/重构，因此阐明心脏成纤维细胞增殖的调节因素具有重要意义。腺苷是一种由心肌细胞大量产生的核苷，对血管平滑肌细胞具有抗丝性；然而，腺苷对心脏成纤维细胞增殖的影响尚不清楚。本研究的目的是表征外源性和内源性（心脏成纤维细胞来源）腺苷对心脏成纤维细胞增殖的影响。方法和结果：用2.5% FCS刺激生长受阻的心脏成纤维细胞，在存在和不存在腺苷、2-氯腺苷（稳定的腺苷类似物）或腺苷水平调节剂的情况下，包括(1)红-9-（2-羟基-3-壬基）腺嘌呤（EHNA；腺苷脱氨酶抑制剂）；(2)双嘧达莫（腺苷转运阻滞剂）；(3)碘结核菌素（腺苷激酶抑制剂）。通过DNA合成（[H-3]胸腺嘧啶掺入）和细胞计数评估，所有这些药物均以浓度依赖的方式抑制fcs诱导的心脏成纤维细胞增殖。EHNA、双嘧达莫和碘结核菌素分别添加到心脏成纤维细胞时，使细胞外腺苷水平增加2.3- 5.6倍，EHNA+碘结核菌素或EHNA+碘结核菌素+双嘧达莫使细胞外腺苷水平增加160 - 690倍。KF17837（选择性A(2)拮抗剂）和DPSPX（非选择性A(2)拮抗剂）均能阻断2-氯腺苷、EHNA和双嘧达蒙对DNA合成的抑菌作用，但DPCPX（选择性A(1)拮抗剂）却不能，这表明A（2A）和/或A（2B）参与了DNA合成，但排除了A(1)受体的参与。CGS21680（选择性A（2A）激动剂）缺乏作用，排除了A（2A）受体的参与，提示A（2B）受体起主要作用。这一结论得到了四种腺苷类似物的等级效价的证实。结论心脏成纤维细胞可合成腺苷，外源性和心脏成纤维细胞来源的腺苷通过激活A（2B）受体抑制心脏成纤维细胞增殖。心脏成纤维细胞衍生的腺苷可能通过调节心脏成纤维细胞增殖来调节心脏肥大和/或重塑。
Background Because proliferation of cardiac fibroblasts participates in cardiac hypertrophy/remodeling associated with hypertension and myocardial infarction, it is important to elucidate factors regulating cardiac fibroblast proliferation. Adenosine, a nucleoside abundantly produced by cardiac cells, is antimitogenic vis-g-vis vascular smooth muscle cells; however, the effect of adenosine on cardiac fibroblast proliferation is unknown. The objective of this study was to characterize the effects of exogenous and endogenous (cardiac fibroblast-derived) adenosine on cardiac fibroblast proliferation.Methods and Results Growth-arrested cardiac fibroblasts were stimulated with 2.5% FCS in the presence and absence of adenosine, 2-chloroadenosine (stable adenosine analogue), or modulators of adenosine levels, including (1) erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA; adenosine deaminase inhibitor); (2) dipyridamole (adenosine transport blocker); and (3) iodotubericidin (adenosine kinase inhibitor). All of these agents inhibited, in a concentration-dependent manner, FCS-induced cardiac fibroblast proliferation as assessed by DNA synthesis ([H-3]thymidine incorporation) and cell counting. EHNA, dipyridamole, and iodotubericidin increased extracellular levels of adenosine by 2.3- to 5.6-fold when added separately to cardiac fibroblasts, and EHNA+ iodotubericidin or EHNA + iodotubericidin + dipyridamole increased extracellular adenosine levels by >690-fold. Both KF17837 (selective A(2) antagonist) and DPSPX (nonselective A(2) antagonist) but not DPCPX (selective A(1) antagonist) blocked the antimitogenic effects of 2-chloroadenosine, EHNA, and dipyridamole on DNA synthesis, suggesting the involvement of A(2A) and/or A(2B) but excluding the participation of A(1) receptors. The lack of effect of CGS21680 (selective A(2A) agonist) excluded involvement of A(2A) receptors and suggested a major role for A(2B) receptors. This conclusion was confirmed by the rank order potencies of four adenosine analogues.Conclusions Cardiac fibroblasts synthesize adenosine,and exogenous and cardiac fibroblast-derived adenosine inhibits cardiac fibroblast proliferation via activation of A(2B) receptors. Cardiac fibroblast-derived adenosine may regulate cardiac hypertrophy and/or remodeling by modulating cardiac fibroblast proliferation.