Abstract：
The dietary approach to stop hypertension (DASH) diet combines the antihypertensive effect of a low sodium and high potassium diet. In particular, the potassium component of the diet acts as a switch in the distal convoluted tubule to reduce sodium reabsorption, similar to a diuretic but without the side effects. Previous trials to understand the mechanism of the DASH diet were based on animal models and did not characterize changes in human ion channel protein abundance. More recently, protein cargo of urinary extracellular vesicles (uEVs) has been shown to mirror tissue content and physiological changes within the kidney. We designed an inpatient open label nutritional study transitioning hypertensive volunteers from an American style diet to DASH diet to examine physiological changes in adults with stage 1 hypertension otherwise untreated (Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER 3rd, Simons-Morton DG, Karanja N, Lin PH; DASH-Sodium Collaborative Research Group. N Engl J Med 344: 3-10, 2001). Urine samples from this study were used for proteomic characterization of a large range of pure uEVs (small to large) to reveal kidney epithelium changes in response to the DASH diet. These samples were collected from nine volunteers at three time points, and mass spectrometry identified 1,800 proteins from all 27 samples. We demonstrated an increase in total SLC12A3 [sodium-chloride cotransporter (NCC)] abundance and a decrease in aquaporin-2 (AQP2) in uEVs with this mass spectrometry analysis, immunoblotting revealed a significant increase in the proportion of activated (phosphorylated) NCC to total NCC and a decrease in AQP2 from day 5 to day 11. This data demonstrates that the human kidney\'s response to nutritional interventions may be captured noninvasively by uEV protein abundance changes. Future studies need to confirm these findings in a larger cohort and focus on which factor drove the changes in NCC and AQP2, to which degree NCC and AQP2 contributed to the antihypertensive effect and address if some uEVs function also as a waste pathway for functionally inactive proteins rather than mirroring protein changes.NEW & NOTEWORTHY Numerous studies link DASH diet to lower blood pressure, but its mechanism is unclear. Urinary extracellular vesicles (uEVs) offer noninvasive insights, potentially replacing tissue sampling. Transitioning to DASH diet alters kidney transporters in our stage 1 hypertension cohort: AQP2 decreases, NCC increases in uEVs. This aligns with increased urine volume, reduced sodium reabsorption, and blood pressure decline. Our data highlight uEV protein changes as diet markers, suggesting some uEVs may function as waste pathways. We analyzed larger EVs alongside small EVs, and NCC in immunoblots across its molecular weight range.
摘要：
停止高血压（DASH）饮食的饮食方法，钠含量低，钾含量高，通过减少肾脏远曲小管中的钠再吸收而起到利尿剂的作用，但没有副作用。先前基于动物模型的研究没有探索人类离子通道蛋白的变化。最近对尿液细胞外囊泡（uEV）的见解表明，它们反映了肾脏组织和生理修饰。在我们的住院研究中，我们将高血压志愿者从美国饮食转变为DASH饮食，检查1期未经治疗的高血压患者的变化。我们分析了大量的纯uEV，从小到大,在三个时间点的九名志愿者的尿液样本中。这些uEV的质谱鉴定了1800种蛋白质，显示SCL12A3（NCC）增加，水通道蛋白2（AQP2）减少。免疫印迹显示从第5天到第11天,活化(磷酸化)NCC与总NCC的比率增加,AQP2降低,表明DASH饮食通过uEV蛋白丰度变化诱导可测量的肾脏反应。这种非侵入性方法为饮食的肾脏机制提供了新的见解。未来的研究应该在更大的队列中证实这些发现，澄清NCC和AQP2变化背后的驱动因素，它们对高血压的影响，并研究uEV是否也作为非活性蛋白质的废物途径，扩大我们对饮食对肾脏生理影响的理解。
