Cai Weiyan, Yang Miyi, Zhao Qinghe, Yi Guohua, Lin Peihui, Chen Apeng, De Gejing
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.
Department of Medicine, The University of Texas at Tyler School of Medicine, Tyler, Texas, USA.
Int J Rheum Dis. 2025 Jan;28(1):e70034. doi: 10.1111/1756-185X.70034.
Urate transporter 1 (URAT1) is a well-known therapeutic target for reducing urate levels in the treatment of hyperuricemia and gout. However, current pharmacological studies have failed to evaluate the efficacy of URAT1 inhibitors in non-primate animal models. We established a human URAT1 (hURAT1) transgenic knock-in (KI) mouse model to assess uricosuric agents' effectiveness and characterize URAT1-caused pathogenesis.
We generated hURAT1 transgenic mice using CRISPR/Cas9 KI technique. mUrat1 knockout was achieved by replacing exon 1 coding sequence with a human SLC22A12 coding sequence (CDS)-pA cassette. Based on the above transgenic mice, a hyperuricemia model was further established by hypoxanthine administration.
The hURAT1-KI mice successfully expressed hURAT1 protein to the apical side of the kidney proximal tubule epithelium, where native human URAT1 is localized in human kidney. Upon hypoxanthine challenge, the blood uric acid (UA) level was elevated in hURAT1-KI mice (251 μmol/L), showing an approximately 37% increase compared to wild-type (WT) mice (183.5 μmol/L). The elevated blood UA level could be alleviated by hURAT1 inhibitor benzbromarone treatment in the hURAT1-KI mice (164.2 μmol/L vs. 251 μmol/L, p < 0.05) whereas no response was observed in WT littermates (168.8 μmol/L vs. 183.5 μmol/L).
The hURAT1-KI hyperuricemia mouse model would be valuable for preclinical evaluation of gout treatment with urate-lowering drugs and for studying UA metabolic complexities in humans.
尿酸转运蛋白1（URAT1）是治疗高尿酸血症和痛风时降低尿酸水平的一个著名治疗靶点。然而，目前的药理学研究未能在非灵长类动物模型中评估URAT1抑制剂的疗效。我们建立了一种人URAT1（hURAT1）转基因敲入（KI）小鼠模型，以评估促尿酸排泄剂的有效性，并表征URAT1引发的发病机制。
我们使用CRISPR/Cas9 KI技术生成了hURAT1转基因小鼠。通过用人SLC22A12编码序列（CDS）-pA盒替换外显子1编码序列，实现了mUrat1基因敲除。基于上述转基因小鼠，通过给予次黄嘌呤进一步建立了高尿酸血症模型。
hURAT1-KI小鼠在肾近端小管上皮细胞顶端成功表达hURAT1蛋白，而天然人URAT1在人肾脏中就定位于此。在次黄嘌呤攻击后，hURAT1-KI小鼠的血尿酸（UA）水平升高（251μmol/L），与野生型（WT）小鼠（183.5μmol/L）相比增加了约37%。hURAT1-KI小鼠中，hURAT1抑制剂苯溴马隆治疗可缓解升高的血尿酸水平（164.2μmol/L对251μmol/L，p<0.05），而野生型同窝小鼠无反应（168.8μmol/L对183.5μmol/L）。
hURAT1-KI高尿酸血症小鼠模型对于用降尿酸药物治疗痛风的临床前评估以及研究人类尿酸代谢复杂性具有重要价值。
