Department of Biology, University of Pisa, Via San Zeno 31, Pisa, Italy.
Naunyn Schmiedebergs Arch Pharmacol. 2013 Apr;386(4):269-78. doi: 10.1007/s00210-012-0828-x. Epub 2013 Jan 3.
Beta-adrenergic receptors (β-ARs) play a role in angiogenic processes that characterize neovascularization-associated retinal diseases, but the role of β3-ARs has not been disclosed yet. We used ex vivo retinal explants to investigate the role of β3-ARs in regulating vascular endothelial growth factor (VEGF) release associated with hypoxia. Whether nitric oxide (NO) mediates β3-AR regulation of VEGF release was also investigated. β3-AR activation was obtained using BRL 37344, whereas SR59230A, L-748,337, or specific siRNAs were used to block β3-ARs. Pharmacological approaches were used to interfere with the NO pathway. Western blot was used to determine β-AR levels. Enzyme-linked immunosorbent assay was used to measure VEGF release. NO production was assessed by a colorimetric assay. We found that hypoxia upregulates β3-ARs. In addition, we observed that β3-AR activation with BRL 37344 increases VEGF release in response to hypoxia. Either β3-AR blocker or β3-AR silencing downregulates drastically hypoxic levels of VEGF. With experiments using NO synthase (NOS) blockade with L-NAME, NOS activation with fluvastatin or NO supplementation with SNAP, we demonstrated that β3-ARs and VEGF are functionally coupled via the NO pathway. In summary, the data presented here support the assumption that β3-ARs are involved in the regulation of angiogenic responses to hypoxia through the NO signalling, a key pathway in hypoxic/ischemic diseases. Although extrapolation of these data to the human situation is difficult, these findings may help to explore the possible role of β3-ARs in vascularization-associated disorders.
β-肾上腺素能受体（β-AR）在血管生成过程中发挥作用，这些过程是新生血管相关视网膜疾病的特征，但β3-AR 的作用尚未揭示。我们使用离体视网膜外植体研究β3-AR 在调节与缺氧相关的血管内皮生长因子（VEGF）释放中的作用。还研究了一氧化氮（NO）是否介导β3-AR 对 VEGF 释放的调节。使用 BRL 37344 激活β3-AR，而使用 SR59230A、L-748337 或特异性 siRNA 阻断β3-AR。使用药理学方法干扰 NO 途径。使用 Western blot 确定β-AR 水平。使用酶联免疫吸附测定法测量 VEGF 释放。通过比色测定法评估 NO 产生。我们发现缺氧上调β3-AR。此外，我们观察到 BRL 37344 激活β3-AR 会增加缺氧时 VEGF 的释放。β3-AR 阻断剂或β3-AR 沉默会急剧下调低氧水平的 VEGF。使用 L-NAME 阻断 NOS 、 fluvastatin 激活 NOS 或 SNAP 补充 NO 的实验，我们证明β3-AR 和 VEGF 通过 NO 信号通路功能偶联。总之，这里提供的数据支持这样的假设，即β3-AR 通过 NO 信号通路参与调节对缺氧的血管生成反应，NO 信号通路是缺氧/缺血性疾病中的关键途径。尽管将这些数据外推到人类情况很困难，但这些发现可能有助于探索β3-AR 在血管生成相关疾病中的可能作用。
