Wnt signaling is a principal pathway regulating the essential activities of cell proliferation. Here, we investigated the effect of Wnt/β-catenin signaling on in vivo drug-induced renal injury through the deletion of Dact2, a Wnt antagonist, and deciphered the underlying mechanism. Wild-type (WT) and Dact2 knockout (KO) mice were administered a single intraperitoneal injection of cisplatin to induce renal injury. The injury was alleviated in Dact2 KO mice, which showed lower levels of blood urea nitrogen and creatinine. RNA sequencing revealed 194 differentially expressed genes (DEGs) between WT and Dact2 KO mouse kidney before cisplatin treatment. Among them, higher levels of Igf1, one of the Wnt target genes responsible for “Positive regulation of cell proliferation” in KO mice, were confirmed along with the induction of Ki67 expression. In RNA-seq analysis comparing WT and Dact2 KO mice after cisplatin treatment, genes related to “Apoptosis” and “Activation of mitogen-activated protein kinase (MAPK) activity” were among the downregulated DEGs in KO mice. These results were corroborated in western blotting of proteins related to apoptosis and proapoptotic MAPK pathway; the expression of which was found to be lower in cisplatin-treated KO mice. Importantly, β-catenin was found to directly bind to and regulate the transcription of Igf1, leading to the alleviation of cisplatin-induced cytotoxicity by the Wnt agonist, CHIR-99021. In addition, Igf1 knockdown accelerated cisplatin-induced cytotoxicity, accompanied by the MAPK upregulation. Our findings suggest that Dact2 knockout could protect cisplatin-induced nephrotoxicity by inhibiting apoptosis, possibly through the regulation of the Igf1-MAPK axis associated with Wnt/β-catenin signaling.

Wnt 信号传导是调节细胞增殖基本活动的主要途径。在这里，我们通过删除Wnt 拮抗剂Dact2来研究 Wnt/β-catenin 信号传导对体内药物诱导的肾损伤的影响，并破译了潜在的机制。对野生型（WT）和Dact2敲除（KO）小鼠进行单次腹腔注射顺铂以诱导肾损伤。Dact2 KO 小鼠的损伤减轻，血液尿素氮和肌酐水平较低。RNA测序揭示了顺铂治疗前WT和Dact2 KO小鼠肾脏之间存在194个差异表达基因(DEG)。其中，随着 Ki67 表达的诱导，证实了在 KO 小鼠中负责“正向调节细胞增殖”的 Wnt 靶基因之一Igf1水平较高。在比较顺铂治疗后的 WT 和Dact2 KO 小鼠的 RNA-seq 分析中，与“细胞凋亡”和“丝裂原活化蛋白激酶 (MAPK) 活性的激活”相关的基因属于 KO 小鼠中下调的 DEG。这些结果在与凋亡和促凋亡 MAPK 通路相关的蛋白质的蛋白质印迹中得到了证实；发现其表达在顺铂治疗的 KO 小鼠中较低。重要的是，β-连环蛋白被发现直接结合并调节Igf1的转录，从而减轻 Wnt 激动剂 CHIR-99021 顺铂诱导的细胞毒性。此外，Igf1敲低加速了顺铂诱导的细胞毒性，并伴有 MAPK 上调。我们的研究结果表明，Dact2敲除可以通过抑制细胞凋亡来保护顺铂诱导的肾毒性，这可能是通过调节与 Wnt/β-catenin 信号传导相关的 Igf1-MAPK 轴来实现的。