近端小管特异性增强ATRAP对小鼠残余肾慢性肾病模型高血压的影响。

Effects of proximal tubule-specific ATRAP enhancement on hypertension in a remnant kidney chronic kidney disease model of mice.

作者信息

Okami Naohito, Wakui Hiromichi, Tanaka Shohei, Kobayashi Ryu, Tsukamoto Shunichiro, Taguchi Shinya, Morita Ryutaro, Kubo Eisuke, Yamashita Akio, Azushima Kengo, Tamura Kouichi

机构信息

Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-Ku, Yokohama, 236-0004, Japan.

Department of Investigative Medicine Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.

出版信息

Sci Rep. 2025 Jul 28;15(1):27391. doi: 10.1038/s41598-025-12168-3.

Abstract

Chronic kidney disease (CKD) frequently accompanies hypertension, exacerbating CKD progression in a vicious cycle. Angiotensin II type 1 receptor-associated protein (ATRAP) promotes AT1 receptor internalization to inhibit hyperactivation of its downstream signaling. We previously reported that the downregulation of renal ATRAP expression had a critical role in the development of hypertension in a remnant kidney CKD model, through activation of epithelial sodium channel (ENaC) pathway. Although the distal-tubule was highlighted in CKD-related hypertension, the proximal tubule's role remained unclear. We generated proximal tubule-specific ATRAP transgenic (PT-ATRAP Tg) mice under the control of the Npt2 promoter and compared the effects of 5/6 nephrectomy (Nx) on blood pressure (BP) with those in littermate control (LC) wild-type mice. Immunohistochemical and laser microdissection analyses revealed that the proximal tubule-specific overexpression of ATRAP in PT-ATRAP Tg mice resulted in approximately 15-fold increase in ATRAP mRNA expression in the proximal tubules compared to LC mice. There were no significant differences in body weight, systolic BP, heart rate, and renal function between PT-ATRAP Tg and LC mice at baseline before surgery. Furthermore, twelve weeks after surgery, both PT-ATRAP Tg and LC mice that underwent 5/6 nephrectomy showed a similar increase in systolic BP compared to sham-operated mice, with no significant differences. Additionally, 5/6 Nx elevated renal ENaCα expression similarly in both groups. In conclusion, increased ATRAP expression in the proximal tubules does not affect hypertension in the remnant kidney CKD model, suggesting a pathological significance of distal tubules in this disease model.

摘要

慢性肾脏病(CKD)常伴有高血压,二者恶性循环,加速CKD进展。血管紧张素II 1型受体相关蛋白(ATRAP)可促进AT1受体内化,抑制其下游信号过度激活。我们之前报道,在残余肾CKD模型中,肾脏ATRAP表达下调通过激活上皮钠通道(ENaC)途径,在高血压发生发展中起关键作用。虽然远端小管在CKD相关高血压中受到关注,但近端小管的作用仍不清楚。我们在Npt2启动子控制下构建了近端小管特异性ATRAP转基因(PT-ATRAP Tg)小鼠,并将5/6肾切除(Nx)对血压(BP)的影响与同窝对照(LC)野生型小鼠进行比较。免疫组织化学和激光显微切割分析显示,与LC小鼠相比,PT-ATRAP Tg小鼠近端小管中ATRAP特异性过表达导致近端小管中ATRAP mRNA表达增加约15倍。手术前基线时,PT-ATRAP Tg小鼠和LC小鼠在体重、收缩压、心率和肾功能方面无显著差异。此外,手术后12周,与假手术小鼠相比,接受5/6肾切除的PT-ATRAP Tg小鼠和LC小鼠收缩压均有相似程度的升高,无显著差异。此外,5/6 Nx使两组肾脏ENaCα表达均同样升高。总之,近端小管中ATRAP表达增加对残余肾CKD模型中的高血压无影响,提示远端小管在该疾病模型中的病理意义。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/6775/12304191/af4935a06d8a/41598_2025_12168_Fig1_HTML.jpg

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