A receptive endometrium is required in a successful embryo implantation. The ubiquitination-induced β-catenin degradation is related to the implantation failure.This study aimed to elucidate whether miR-23a-3p regulates endometrial receptivity via the modulation of β-catenin ubiquitination.The expressions of miR-23a-3p and CUL3 were detected in endometrial epithelial cells (EECs) isolated from pregnant mice and in hormone-induced EEC-like Ishikawa cells. The ubiquitination experiment was performed to explore the effect of CUL3 and miR-23a-3p on β-catenin ubiquitination level. The trophoblast attachment was detected by co-culturing JAR (choriocarcinoma cell line) spheroids with Ishikawa cell monolayers. miR-23a-3p was upregulated while CUL3 was downregulated in EECs at day 4 after pregnancy compared with day 1, as well as in hormone-induced Ishikawa cells. miR-23a-3p positively regulated the protein level of β-catenin without affecting the mRNA level. The ubiquitination and degradation of β-catenin was suppressed by miR-23a-3p, while it was promoted by CUL3. Immunoprecipitation confirmed the binding between CUL3 and β-catenin. Luciferase reporter assay confirmed the target relationship between miR-23a-3p and CUL3. The ubiquitination of β-catenin was modulated by the miR-23a-3p/CUL3 pathway. The overexpression of miR-23a-3p promoted JAR spheroid attachments in Ishikawa cells. miR-23a-3p is beneficial for the endometrial receptivity and embryo implantation, whose mechanism is partly through the modulation of CUL3/β-catenin.
Kai Huang, Gezi Chen, Wenqian Fan and Linli Hu
Yujia Pan, Weikang Yun, Bingshuai Shi, Rongjun Cui, Chi Liu, Zhong Ding, Jialin Fan, Wenqian Jiang, Jiebing Tang, Tianhu Zheng, Xiaoguang Yu and Ying Liu
miR-146b-5p is overexpressed in papillary thyroid carcinoma (PTC) and is thought to be a related diagnostic marker. Previous studies have indicated the effects of iodine on oncogenic activation. However, the effect of iodine on the proliferation of PTC cells and the associated underlying mechanisms remain unclear. We found that miR-146b-5p was downregulated and smad4 was upregulated in patients exposed to high iodine concentration by in situ hybridisation (ISH) and immunohistochemical (IHC). NaI (10−3 M) treatment downregulated miR-146b-5p and upregulated Smad4 in PTC cell lines. Luciferase assay was used to confirm that Smad4 is a target of miR-146b-5p. Furthermore, MTT assay and cell cycle analysis indicated that 10−3 M NaI suppressed cell proliferation and caused G0/G1 phase arrest. Real-time PCR and Western blotting demonstrated that 10−3 M NaI increased p21, p27, and p57 levels and reduced cyclin D1 levels in PTC cells. Our findings suggest that 10−3 M NaI increases Smad4 levels through repression of miR-146b-5p expression, curbing the proliferation in PTC.