Rubattu Speranza, Cotugno Maria, Bianchi Franca, Sironi Luigi, Gelosa Paolo, Stanzione Rosita, Forte Maurizio, De Sanctis Claudia, Madonna Michele, Marchitti Simona, Pignieri Alice, Sciarretta Sebastiano, Volpe Massimo
aIRCCS Neuromed, Pozzilli, Isernia bDepartment of Clinical and Molecular Medicine, School of Medicine and Psychology, Sapienza University of Rome, Rome cDepartment of Pharmacological and Biomolecular Sciences, University of Milan dCentro Cardiologico Monzino IRCCS, Milan eDepartment of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy.
J Hypertens. 2017 Sep;35(9):1857-1871. doi: 10.1097/HJH.0000000000001374.
Uncoupling protein-2 (UCP2), a mitochondrial anion transporter involved in mitochondrial uncoupling, limiting reactive oxygen species formation, is significantly downregulated in kidneys of high-salt-fed stroke-prone spontaneously hypertensive rat (SHRSP), where it associates with increased renal damage occurrence.
We aimed at establishing whether UCP2 differential expression associates with renal damage in two stroke-resistant spontaneously hypertensive rat (SHRSR)/SHRSP-derived stroke congenic lines. For this purpose, SHRSR, SHRSP, and two reciprocal stroke congenic lines carrying the (D1Rat134-Mt1pa) segment of chromosome 1 were fed with Japanese style diet for 8 weeks. At 4, 6, and 8 weeks of Japanese diet, kidneys were removed and analyzed for UCP2 gene and protein expression [UCP2 maps within (D1Rat134-Mt1pa)]; nuclear factor kappa-light-chain-enhancer of activated B cells protein expression; oxidized total protein levels; mitochondrial function; gene expression of cubulin, megalin, and nephrin. At 6 and 8 weeks of Japanese diet, histological damage and percentage of high molecular weight urinary proteins excretion were assessed.
Introgression of UCP2 in the SHRSP configuration within the SHRSR genome led to UCP2 downregulation upon Japanese diet, as compared with the SHRSR, with significantly reduced ATP levels, increased rate of inflammation, oxidative stress, renal damage, and excretion of high molecular weight proteins. The opposite phenomena were observed in the reciprocal congenic line, compared with the SHRSP. In vitro, high-NaCl medium led to UCP2 downregulation, increased apoptosis/necrosis, and reduced viability in primary renal proximal tubular epithelial cells isolated from SHRSP. Exposure of the SHRSP/proximal tubular epithelial cells to recombinant UCP2 rescued the high-salt-dependent deleterious effects.
A differential UCP2 expression associates with different degree of renal damage upon Japanese diet in two SHRSR/SHRSP-derived stroke congenic lines through modulation of mitochondrial function, inflammation, and oxidative stress.
解偶联蛋白2（UCP2）是一种参与线粒体解偶联、限制活性氧生成的线粒体阴离子转运蛋白，在高盐喂养的易中风自发性高血压大鼠（SHRSP）的肾脏中显著下调，且与肾脏损伤发生率增加相关。
我们旨在确定UCP2的差异表达是否与两种抗中风自发性高血压大鼠（SHRSR）/SHRSP衍生的中风同源系中的肾脏损伤有关。为此，将SHRSR、SHRSP以及两条携带1号染色体（D1Rat134-Mt1pa）片段的反向中风同源系用日式饮食喂养8周。在日式饮食喂养的第4、6和8周，取出肾脏并分析UCP2基因和蛋白表达[UCP2定位于（D1Rat134-Mt1pa）内]；活化B细胞核因子κ轻链增强子蛋白表达；氧化总蛋白水平；线粒体功能；立方体细胞素、巨膜蛋白和nephrin的基因表达。在日式饮食喂养的第6和8周，评估组织学损伤和高分子量尿蛋白排泄百分比。
与SHRSR相比，在日式饮食条件下，UCP2在SHRSR基因组内以SHRSP构型渗入导致UCP2下调，ATP水平显著降低，炎症、氧化应激、肾脏损伤和高分子量蛋白排泄率增加。与SHRSP相比，在反向同源系中观察到相反的现象。在体外，高NaCl培养基导致从SHRSP分离的原代肾近端小管上皮细胞中UCP2下调、凋亡/坏死增加和活力降低。将SHRSP/近端小管上皮细胞暴露于重组UCP2可挽救高盐依赖性有害作用。
在两种SHRSR/SHRSP衍生的中风同源系中，通过调节线粒体功能、炎症和氧化应激，UCP2的差异表达与日式饮食后不同程度的肾脏损伤相关。
