Transcriptional regulation of renal dopamine D1 receptor function during oxidative stress.
Transcriptional regulation of renal dopamine D1 receptor function during oxidative stress.
复制标题
DOI：
10.1161/hypertensionaha.115.05255
复制
发表时间：
2015-05
期刊：
影响因子：
--
通讯作者：
Lokhandwala MF
中科院分区：
文献类型：
--
作者：
Banday AA;Lokhandwala MF
氧化应激、肾脏多巴胺能系统与高血压之间存在密切联系。据报道，活性氧减弱肾近端小管多巴胺受体（D1 R）的功能，从而破坏钠调节并导致高血压。然而，肾D1 R功能障碍的机制尚不清楚。我们研究了氧化还原敏感性转录因子AP 1和SP 3在D1 R基因转录抑制和随后的D1 R信号转导中的作用。人肾（HK 2）近端肾小管细胞处理与促氧化剂L-丁硫氨酸亚砜亚胺（BSO）与和没有抗氧化剂tempol。在HK 2细胞中，BSO引起氧化应激并降低D1 R mRNA和膜受体表达。D1 R激动剂SKF 38393对HK 2细胞Na/K-ATP酶有浓度依赖性抑制作用。然而，SKF 38393不能抑制BSO处理的细胞中的Na/K-ATP酶。BSO增加AP 1和SP 3核表达。用AP 1或SP3特异性siRNA转染可消除BSO诱导的D1 R下调。用BSO处理大鼠4周增加了氧化应激和SP3-AP 1表达，并减少了肾近端小管中D1 R的数量。这些大鼠表现出高血压，SKF 38393未能抑制近端肾小管Na/K-ATP酶活性。对照组大鼠饮用自来水。Tempol本身对D1 R表达或其他信号分子没有影响，但在HK 2细胞和大鼠中阻止BSO诱导的氧化应激，SP3-AP 1上调和D1 R功能障碍。这些数据表明，通过AP 1-SP3激活的氧化应激抑制D1 R转录和功能。Tempol减轻氧化应激，阻断AP 1-SP3激活，预防D1 R功能障碍和高血压。
There exists a strong link between oxidative stress, renal dopaminergic system and hypertension. It is reported that reactive oxygen species attenuate renal proximal tubular dopamine receptor (D1R) function which disrupts sodium regulation and leads to hypertension. The mechanisms for renal D1R dysfunction however are not clear. We investigated the role of redox sensitive transcription factors AP1 and SP3 in transcriptional suppression of D1R gene and subsequent D1R signaling. Human kidney (HK2) proximal tubular cells were treated with a pro-oxidant L-buthionine sulfoximine (BSO) with and without an antioxidant tempol. In HK2 cells BSO caused oxidative stress and reduced D1R mRNA and membrane receptor expression. Incubation of HK2 cells with SKF38393, a D1R agonist, caused a concentration dependent inhibition of Na/K-ATPase. However, SKF38393 failed to inhibit Na/K-ATPase in BSO-treated cells. BSO increased AP1 and SP3 nuclear expression. Transfection with AP1 or SP3 specific siRNA abolished BSO-induced D1R down-regulation. Treatment of rats with BSO for 4 weeks increased oxidative stress and SP3—AP1 expression and reduced D1R numbers in renal proximal tubules. These rats exhibited high blood pressure and SKF38393 failed to inhibit proximal tubular Na/K-ATPase activity. Control rats were kept on tap water. Tempol per se had no effect on D1R expression or other signaling molecules but prevented BSO-induced oxidative stress, SP3—AP1 up-regulation and D1R dysfunction in both HK2 cells and rats. These data shows that oxidative stress via AP1—SP3 activation suppresses D1R transcription and function. Tempol mitigates oxidative stress, blocks AP1—SP3 activation and prevents D1R dysfunction and hypertension.