Amyloid deposition in a mouse model humanized at the transthyretin and retinol-binding protein 4 loci
Amyloid deposition in a mouse model humanized at the transthyretin and retinol-binding protein 4 loci
复制标题
运甲状腺素蛋白和视黄醇结合蛋白 4 位点人源化小鼠模型中的淀粉样蛋白沉积
DOI：
10.1038/s41374-017-0019-y
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发表时间：
2018-04-01
影响因子：
5
通讯作者：
Li, Zhenghua
中科院分区：
文献类型：
--
作者：
Li, Xiangshun;Lyu, Yanyi;Li, Zhenghua
家族性淀粉样多发性神经病是由甲状腺素运载蛋白（TTR）基因点突变引起的常染色体显性遗传病。TTR淀粉样蛋白生成的过程始于TTR四聚体的限速解离。因此，TTR稳定剂，如Tafamidis和Diflunisal，目前正在临床试验中。小鼠模型将有助于测试这些药物的功效。虽然已经产生了几种小鼠模型，但它们都表达小鼠Rbp 4。因此，人TTR与小鼠RBP 4相关联，导致TTR四聚体的不同动力学和热力学稳定性特征。为了克服这个问题，我们先前在TTR和Rbp 4基因座（Ttr hTTRVal 30、Ttr hTTRMet 30和Rbp 4 hRBP 4）两者处产生人源化小鼠品系。通过使这些小鼠交配，我们产生了双重人源化小鼠品系Ttr hTTRVal 30/hTTRVal 30：Rbp 4 hRBP 4/hRBP 4和Ttr hTTRVal 30/Met 30：Rbp 4 hRBP 4/hRBP 4。我们使用野生型（Ttr +/+：Tg[6.0hTTRMet30]）或敲除Ttr背景（Ttr-/-：Tg[6.0hTTRMet30]）的常规转基因小鼠品系作为参考品系。双重人源化小鼠显示1/25的血清hTTR和1/40的血清hRBP 4水平。然而，淀粉样蛋白沉积在Ttr hTTRVal 30/Met 30：Rbp 4 hRBP 4/hRBP 4中比在常规转基因小鼠品系中更明显。此外，在携带野生型人TTR基因的Ttr hTTRVal 30/hTTRVal 30：Rbp 4 hRBP 4/hRBP 4小鼠中也观察到类似量的淀粉样蛋白沉积。此外，在坐骨神经中首次观察到淀粉样蛋白沉积，而没有任何额外的遗传变化。在所有菌株中，抗TTR抗体阳性沉积物在较早的年龄和较高的百分比比淀粉样纤维沉积。在双重人源化小鼠中，血清的凝胶过滤分析显示大多数hTTR不含hRBP 4，表明游离TTR对淀粉样蛋白沉积的重要性。
Familial amyloidotic polyneuropathy is an autosomal dominant disorder caused by a point mutation in the transthyretin (TTR) gene. The process of TTR amyloidogenesis begins with rate-limiting dissociation of the TTR tetramer. Thus, the TTR stabilizers, such as Tafamidis and Diflunisal, are now in clinical trials. Mouse models will be useful to testing the efficacy of these drugs. Although several mouse models have been generated, they all express mouse Rbp4. Thus, human TTR associates with mouse RBP4, resulting in different kinetic and thermodynamic stability profiles of TTR tetramers. To overcome this problem, we previously produced humanized mouse strains at both the TTR and Rbp4 loci (Ttr hTTRVal30 , Ttr hTTRMet30 , and Rbp4 hRBP4 ). By mating these mice, we produced double-humanized mouse strains, Ttr hTTRVal30/hTTRVal30 :Rbp4 hRBP4/hRBP4 and Ttr hTTRVal30/Met30 :Rbp4 hRBP4/hRBP4 . We used conventional transgenic mouse strains on a wild-type (Ttr +/+ :Tg[6.0hTTRMet30]) or knockout Ttr background (Ttr−/− :Tg[6.0hTTRMet30]) as reference strains. The double-humanized mouse showed 1/25 of serum hTTR and 1/40 of serum hRBP4 levels. However, amyloid deposition was more pronounced in Ttr hTTRVal30/Met30 :Rbp4 hRBP4/hRBP4 than in conventional transgenic mouse strains. In addition, a similar amount of amyloid deposition was also observed in Ttr hTTRVal30/ hTTRVal30 :Rbp4 hRBP4/ hRBP4 mice that carried the wild-type human TTR gene. Furthermore, amyloid deposition was first observed in the sciatic nerve without any additional genetic change. In all strains, anti-TTR antibody-positive deposits were found in earlier age and at higher percentage than amyloid fibril deposition. In double-humanized mice, gel filtration analysis of serum revealed that most hTTR was free of hRBP4, suggesting importance of free TTR for amyloid deposition.