Dunaway Luke S, Cook Anthony K, Botta Davide, Molina Patrick A, d'Uscio Livius V, Katusic Zvonimir S, Pollock David M, Inscho Edward W, Pollock Jennifer S
Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL USA.
Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, USA.
bioRxiv. 2023 Mar 10:2023.03.08.531731. doi: 10.1101/2023.03.08.531731.
We aimed to identify new mechanisms by which a high salt diet (HS) decreases NO production in kidney microvascular endothelial cells. Specifically, we hypothesized HS impairs NO signaling through a histone deacetylase 1 (HDAC1)-dependent mechanism.
Male Sprague Dawley rats were fed normal salt diet (NS; 0.49% NaCl) or high salt diet (4% NaCl) for two weeks. NO signaling was assessed by measuring L-NAME induced vasoconstriction of the afferent arteriole using the blood perfused juxtamedullary nephron (JMN) preparation. In this preparation, kidneys were perfused with blood from a donor rat on a matching or different diet to that of the kidney donor. Kidney endothelial cells were isolated with magnetic activated cell sorting and HDAC1 activity was measured.
We found that HS impaired NO signaling in the afferent arteriole. This was restored by inhibition of HDAC1 with MS-275. Consistent with these findings, HDAC1 activity was increased in kidney endothelial cells. We further found the loss of NO to be dependent upon the diet of the blood donor rather than the diet of the kidney donor and the plasma from HS fed rats to be sufficient to induce dysfunction suggesting a humoral factor, we termed Plasma Derived Endothelial-dysfunction Mediator (PDEM), mediates the endothelial dysfunction. The antioxidants, PEG-SOD and PEG-catalase, as well as the NOS cofactor, tetrahydrobiopterin, restored NO signaling.
We conclude that HS activates endothelial HDAC1 through PDEM leading to decreased NO signaling. This study provides novel insights into the molecular mechanisms by which a HS decreases renal microvascular endothelial NO signaling.
我们旨在确定高盐饮食（HS）降低肾微血管内皮细胞中一氧化氮（NO）生成的新机制。具体而言，我们假设HS通过组蛋白去乙酰化酶1（HDAC1）依赖性机制损害NO信号传导。
将雄性Sprague Dawley大鼠喂食正常盐饮食（NS；0.49%氯化钠）或高盐饮食（4%氯化钠）两周。使用血液灌注的近髓肾单位（JMN）制剂，通过测量L- NAME诱导的传入小动脉血管收缩来评估NO信号传导。在该制剂中，用来自供体大鼠的血液灌注肾脏，供体大鼠的饮食与肾脏供体的饮食匹配或不同。用磁激活细胞分选法分离肾内皮细胞并测量HDAC1活性。
我们发现HS损害了传入小动脉中的NO信号传导。用MS - 275抑制HDAC1可恢复此现象。与这些发现一致，肾内皮细胞中的HDAC1活性增加。我们进一步发现NO的丧失取决于供血者的饮食而非肾脏供体的饮食，并且来自HS喂养大鼠的血浆足以诱导功能障碍，提示一种体液因子，我们称之为血浆源性内皮功能障碍介质（PDEM），介导内皮功能障碍。抗氧化剂聚乙二醇超氧化物歧化酶（PEG - SOD）和聚乙二醇过氧化氢酶，以及一氧化氮合酶（NOS）辅因子四氢生物蝶呤，可恢复NO信号传导。
我们得出结论，HS通过PDEM激活内皮HDAC1，导致NO信号传导减少。本研究为HS降低肾微血管内皮NO信号传导的分子机制提供了新的见解。
