The Cancer Center of Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China.
Liangxiang Hospital, Fangshan District, Beijing, 102401, China.
Dig Dis Sci. 2018 May;63(5):1200-1209. doi: 10.1007/s10620-018-4973-z. Epub 2018 Feb 27.
As a potential tumor suppressor gene, Claudin-7 (Cldn7), which is a component of tight junctions, may play an important role in colorectal cancer occurrence and development.
To generate a knockout mouse model of inducible conditional Cldn7 in the intestine and analyze the phenotype of the mice after induction with tamoxifen.
We constructed Cldn7-flox transgenic mice and crossed them with Villin-CreERT2 mice. The Cldn7 inducible conditional knockout mice appeared normal and were well developed at birth. We induced Cldn7 gene deletion by injecting different dosages of tamoxifen into the mice and then conducted a further phenotypic analysis.
After induction for 5 days in succession at a dose of 200 µl tamoxifen in sunflower oil at 10 mg/ml per mouse every time, the mice appeared dehydrated, had a lower temperature, and displayed inactivity or death. The results of hematoxylin-eosin staining showed that the intestines of the Cldn7 inducible conditional knockout mice had severe intestinal defects that included epithelial cell sloughing, necrosis, inflammation and hyperplasia. Owing to the death of ICKO mice, we adjusted the dose of tamoxifen to a dose of 100 µl in sunflower oil at 10 mg/ml per mouse (aged more than 8 weeks old) every 4 days. And we could induce atypical hyperplasia and adenoma in the intestine. Immunofluorescent staining indicated that the intestinal epithelial structure was destroyed. Electron microscopy experimental analysis indicated that the intercellular gap along the basolateral membrane of Cldn7 inducible conditional knockout mice in the intestine was increased and that contact between the cells and matrix was loosened.
We generated a model of intestinal Cldn7 inducible conditional knockout mice. Intestinal Cldn7 deletion induced by tamoxifen initiated inflammation and hyperplasia in mice.
Claudin-7（Cldn7）作为一种潜在的肿瘤抑制基因，是紧密连接的组成部分，可能在结直肠癌的发生和发展中发挥重要作用。
构建肠道中诱导型条件性 Claudin-7（Cldn7）基因敲除小鼠模型，并分析经他莫昔芬诱导后小鼠的表型。
我们构建了 Cldn7-flox 转基因小鼠，并与 Villin-CreERT2 小鼠杂交。Cldn7 诱导型条件性基因敲除小鼠出生时外观正常且发育良好。我们通过向小鼠注射不同剂量的他莫昔芬来诱导 Cldn7 基因缺失，然后进行进一步的表型分析。
在每只小鼠每次 10mg/ml 浓度的 200μl 向日葵油中的他莫昔芬连续诱导 5 天后，小鼠出现脱水、体温降低、活动减少或死亡。苏木精-伊红染色的结果显示，Cldn7 诱导型条件性基因敲除小鼠的肠道严重缺陷，包括上皮细胞脱落、坏死、炎症和增生。由于 ICKO 小鼠的死亡，我们将他莫昔芬的剂量调整为每只小鼠 10mg/ml 浓度的 100μl 向日葵油（8 周龄以上），每 4 天一次，可诱导肠道非典型增生和腺瘤。免疫荧光染色显示肠道上皮结构被破坏。电子显微镜实验分析表明，Cldn7 诱导型条件性基因敲除小鼠肠道中沿基底外侧膜的细胞间间隙增加，细胞与基质之间的接触变松。
我们构建了肠道 Cldn7 诱导型条件性基因敲除小鼠模型。经他莫昔芬诱导的肠道 Cldn7 缺失引发了小鼠的炎症和增生。
