Characterization of CD38 in the major cell types of the heart: endothelial cells highly express CD38 with activation by hypoxia-reoxygenation triggering NAD(P)H depletion
Characterization of CD38 in the major cell types of the heart: endothelial cells highly express CD38 with activation by hypoxia-reoxygenation triggering NAD(P)H depletion
复制标题
DOI：
10.1152/ajpcell.00139.2017
复制
发表时间：
2018-03-01
影响因子：
5.5
通讯作者：
Zweier, Jay L.
中科院分区：
文献类型：
--
作者：
Boslett, James;Hemann, Craig;Zweier, Jay L.
心肌缺血再灌注过程中NAD(P)(+) -水解酶CD38被激活，引发NAD(P)(H)耗竭。然而，CD38在心脏主要细胞类型中的存在和作用尚不清楚。因此，我们表征了CD38在心肌细胞、内皮细胞和成纤维细胞中的存在和功能。为了全面评估这些细胞中的CD38，我们通过mRNA测量了基因转录，以及蛋白质表达和酶活性。内皮细胞强烈表达CD38，心肌细胞低表达，成纤维细胞中等水平表达。鉴于CD38在内皮细胞中的高水平表达，以及CD38在内皮功能障碍发病机制中的作用，我们对内皮细胞进行了缺氧-复氧处理，以表征这种应激对CD38表达和活性的影响。基于活性的CD38成像方法和CD38活性测定用于表征常氧和低氧再氧化内皮细胞中的CD38活性，在低氧再氧化后观察到明显的CD38活化。为了测试缺氧再氧化诱导的CD38活化对内皮细胞的影响，我们测量了NAD(P)(H)水平和内皮一氧化氮合酶（eNOS）衍生的NO生成。在缺氧再氧化后，通过抑制或敲低CD38阻止了NADP(H)的明显耗竭和NO的损失，并增加了超氧化物的产生。因此，内皮细胞高表达CD38， CD38被缺氧-再氧化激活，触发CD38介导的NADP(H)耗竭，丧失eNOS介导的NO生成和eNOS解偶联增加。这证明了CD38在内皮中的重要性，并解释了CD38触发缺血后内皮功能障碍的基础。
The NAD(P)(+) -hydrolyzing enzyme CD38 is activated in the heart during the process of ischemia and reperfusion, triggering NAD(P)(H) depletion. However, the presence and role of CD38 in the major cell types of the heart are unknown. Therefore, we characterize the presence and function of CD38 in cardiac myocytes, endothelial cells, and fibroblasts. To comprehensively evaluate CD38 in these cells, we measured gene transcription via mRNA, as well as protein expression and enzymatic activity. Endothelial cells strongly expressed CD38, while only low expression was present in cardiac myocytes with intermediate levels in fibroblasts. In view of this high level expression in endothelial cells and the proposed role of CD38 in the pathogenesis of endothelial dysfunction, endothelial cells were subjected to hypoxia-reoxygenation to characterize the effect of this stress on CD38 expression and activity. An activity-based CD38 imaging method and CD38 activity assays were used to characterize CD38 activity in normoxic and hypoxic-reoxygenated endothelial cells, with marked CD38 activation seen following hypoxia-reoxygenation. To test the impact of hypoxia-reoxygenation-induced CD38 activation on endothelial cells, NAD(P)(H) levels and endothelial nitric oxide synthase (eNOS)-derived NO production were measured. Marked NADP(H) depletion with loss of NO and increase in superoxide production occurred following hypoxia-reoxygenation that was prevented by CD38 inhibition or knockdown. Thus, endothelial cells have high expression of CD38 which is activated by hypoxia-reoxygenation triggering CD38-mediated NADP(H) depletion with loss of eNOS-mediated NO generation and increased eNOS uncoupling. This demonstrates the importance of CD38 in the endothelium and explains the basis by which CD38 triggers post-ischemic endothelial dysfunction.