Wu Hongyan, Yang Jing, Liu Yun-Qiang, Lei Song, Yang Mei, Yang Zhi, Yang Yuan, Hu Zhangxue
Department of Nephrology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Sichuan, Guoxue Alley, 37#, Wuhou District, Chengdu, 610041, China.
Department of Medical Genetics, West China Hospital, Sichuan University, Chengdu, China.
J Transl Med. 2021 Mar 4;19(1):97. doi: 10.1186/s12967-021-02765-x.
Lipoprotein glomerulopathy (LPG) is a rare autosomal dominant kidney disease that is most commonly caused by mutations in ApoE Kyoto (p.R43C) and ApoE Sendai (p.R163P). Differences in phenotype among the various ApoE mutations have been suggested, but the pathogenic role of ApoE Kyoto has not been validated in an animal model. This study intended to establish an ApoE Kyoto murine model and to further compare the pathologic differences between ApoE Kyoto and ApoE Sendai.
Male ApoE-deficient mice, 3 months of age, were divided into five groups, including the AD-ApoE Sendai, AD-ApoE Kyoto, AD-ApoE3, AD-eGFP, and ApoE (-/-) groups. The first four groups received recombinant adenovirus that contained the entire coding regions of the human ApoE Sendai and ApoE Kyoto, apoE3, and eGFP genes, respectively. Fasting blood and urine samples were collected at multiple time points. Lipid profiles and urine albumin-creatinine ratio were measured. Renal and aortic histopathologic alterations were analyzed.
After virus injection, plasma human ApoE was detected and rapidly reached the maximum level at 4-6 days in the AD-ApoE Kyoto and AD-ApoE Sendai groups (17.4 ± 3.1 µg/mL vs.: 22.2 ± 4.5 µg/mL, respectively) and at 2 days in the AD-ApoE3 group (38.4 µg/mL). The serum total cholesterol decreased by 63%, 65%, and 73% in the AD-ApoE Kyoto, AD-ApoE Sendai and AD-ApoE3 groups, respectively. There were no significant changes in serum triglyceride and urinary albumin-creatinine ratio among the five groups. Typical lipoprotein thrombi with positive ApoE staining were detected in the AD-ApoE Kyoto and AD-ApoE Sendai groups. The Oil-red O-positive glomerular area tended to be higher in the AD-ApoE Kyoto group (9.2%) than in the AD-ApoE Sendai (3.9%), AD-ApoE3 (4.8%), AD-eGFP (2.9%), and ApoE (-/-) (3.6%) groups. The atherosclerotic plaque area in the aorta was lower in the group injected with various ApoE mutations than in the group without injection of ApoE mutation.
In this animal study, we first established an ApoE Kyoto mutation murine model and confirmed its pathogenic role in LPG. Our results suggested that LPG may be more severe with the ApoE Kyoto than with the ApoE Sendai.
脂蛋白肾小球病（LPG）是一种罕见的常染色体显性遗传性肾脏疾病，最常见的病因是载脂蛋白E京都型（p.R43C）和载脂蛋白E仙台型（p.R163P）的突变。已有研究提示不同载脂蛋白E突变之间存在表型差异，但载脂蛋白E京都型的致病作用尚未在动物模型中得到验证。本研究旨在建立载脂蛋白E京都型小鼠模型，并进一步比较载脂蛋白E京都型和载脂蛋白E仙台型之间的病理差异。
将3月龄雄性载脂蛋白E缺陷小鼠分为五组，包括AD-载脂蛋白E仙台型组、AD-载脂蛋白E京都型组、AD-载脂蛋白E3组、AD-绿色荧光蛋白组和载脂蛋白E（-/-）组。前四组分别接受含有人类载脂蛋白E仙台型和载脂蛋白E京都型、载脂蛋白E3和绿色荧光蛋白基因完整编码区的重组腺病毒。在多个时间点采集空腹血液和尿液样本。检测血脂谱和尿白蛋白-肌酐比值。分析肾脏和主动脉的组织病理学改变。
病毒注射后，在AD-载脂蛋白E京都型组和AD-载脂蛋白E仙台型组中检测到血浆人载脂蛋白E，并在4-6天迅速达到最高水平（分别为17.4±3.1μg/mL和22.2±4.5μg/mL），在AD-载脂蛋白E3组中2天达到最高水平（38.4μg/mL）。AD-载脂蛋白E京都型组、AD-载脂蛋白E仙台型组和AD-载脂蛋白E3组的血清总胆固醇分别下降了63%、65%和73%。五组之间血清甘油三酯和尿白蛋白-肌酐比值无显著变化。在AD-载脂蛋白E京都型组和AD-载脂蛋白E仙台型组中检测到载脂蛋白E染色阳性的典型脂蛋白血栓。AD-载脂蛋白E京都型组油红O阳性肾小球面积（9.2%）高于AD-载脂蛋白E仙台型组（3.9%）、AD-载脂蛋白E3组（4.8%）、AD-绿色荧光蛋白组（2.9%）和载脂蛋白E（-/-）组（3.6%）。注射各种载脂蛋白E突变体的组主动脉粥样硬化斑块面积低于未注射载脂蛋白E突变体的组。
在本动物研究中，我们首次建立了载脂蛋白E京都型突变小鼠模型，并证实了其在脂蛋白肾小球病中的致病作用。我们的结果提示，与载脂蛋白E仙台型相比，载脂蛋白E京都型导致的脂蛋白肾小球病可能更严重。
