Li Yifan, Gong Hui, Ding Jiangfeng, Zhao Fujuan, Du Jihui, Wan Jun, Zhang Juan, Liu Shaoxiong, Li Jing, Wang Lei, Zhou Bei
Central Laboratory, Huazhong University of Science and Technology Union Shenzhen Hospital and the Affiliated Shenzhen Sixth Hospital of Guangdong Medical University, Shenzhen, China.
Shenzhen Key Lab of Endogenous Infection, Huazhong University of Science and Technology Union Shenzhen Hospital and the Affiliated Shenzhen Sixth Hospital of Guangdong Medical University, Shenzhen, China.
Front Cell Dev Biol. 2020 Mar 17;8:94. doi: 10.3389/fcell.2020.00094. eCollection 2020.
Organogenesis, including renal development, requires an appropriate retinoic acid concentration, which is established by differential expression of aldehyde dehydrogenase 1 family member A2 () and cytochrome P450 family 26 subfamily A/B/C member 1 (). In the fetal kidney, expresses in the developing stroma and renal vesicle and its derivatives but does not present in the ureteric bud. It remains unclear what may contribute to this expression pattern. Here we show that the glycogen synthase kinase 3 alpha/beta (GSK3A/B) inhibitor CHIR99021 significantly represses expression in WiT49, which is a Wilms' tumor cell line that exhibits "triphasic" differential potential and is used as a fetal kidney cell model. CHIR99021 fails to suppress as β-catenin is inhibited, suggesting that the downregulation of ALDH1A2 by CHIR99021 is through Wnt/β-catenin signaling. Ectopic expression of mouse Wnt1, Wnt3a, Wnt4, and Wnt9b represses expression in WiT49 cells. Using immunohistochemistry, we show an inverse correlation of expression with β-catenin in rat E18.5 kidney. ChIP demonstrated that β-catenin is recruited to the promoter, the conserved intron1G, and another site within intron 1 of . Using a luciferase assay, we further show that the promoter and the intron1G element are involved in the repression of expression by CHIR99021. Our work demonstrates that expression can be directly repressed by the Wnt/β-catenin signaling in fetal kidney cells, suggesting that Wnt/β-catenin may play a role in maintaining the expression pattern of in the fetal kidney, thus controlling the availability and localization of retinoic acid and regulating aspects of kidney development.
器官发生，包括肾脏发育，需要适当的视黄酸浓度，这是由醛脱氢酶1家族成员A2（ALDH1A2）和细胞色素P450家族26亚家族A/B/C成员1（CYP26A1/B/C1）的差异表达所建立的。在胎儿肾脏中，ALDH1A2在发育中的基质和肾小泡及其衍生物中表达，但在输尿管芽中不存在。目前尚不清楚是什么导致了这种表达模式。在这里，我们表明糖原合酶激酶3α/β（GSK3A/B）抑制剂CHIR99021显著抑制了WiT49细胞中ALDH1A2的表达，WiT49是一种具有“三相”分化潜能的肾母细胞瘤细胞系，用作胎儿肾细胞模型。由于β-连环蛋白被抑制，CHIR99021未能抑制CYP26A1，这表明CHIR99021对ALDH1A2的下调是通过Wnt/β-连环蛋白信号通路实现的。小鼠Wnt1、Wnt3a、Wnt4和Wnt9b的异位表达抑制了WiT49细胞中ALDH1A2的表达。通过免疫组织化学，我们显示在大鼠E18.5肾脏中ALDH1A2的表达与β-连环蛋白呈负相关。染色质免疫沉淀（ChIP）表明β-连环蛋白被招募到ALDH1A2启动子以及保守的内含子1G和ALDH1A2内含子1内的另一个位点。使用荧光素酶测定，我们进一步表明ALDH1A2启动子和内含子1G元件参与了CHIR99021对ALDH1A2表达的抑制。我们的工作表明，在胎儿肾细胞中，Wnt/β-连环蛋白信号通路可直接抑制ALDH1A2的表达，这表明Wnt/β-连环蛋白可能在维持胎儿肾脏中ALDH1A2的表达模式中发挥作用，从而控制视黄酸的可用性和定位，并调节肾脏发育的各个方面。
