Circ_FBLN1 promotes the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by regulating let-7i-5p/FZD4 axis and Wnt/β-catenin pathway.

Recently, more and more circular RNAs (circRNAs) have been identified in osteogenesis. In this study, we aimed to explore the effect of circ_FBLN1 on the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). The protein levels of osteogenesis-related genes, let-7i-5p, frizzled class receptor 4 (FZD4), Ki67, Wnt6 and β-catenin were measured by western blot assay. The levels of circ_FBLN1, FBLN1 mRNA and FZD4 mRNA were determined by quantitative real-time polymerase chain reaction (qRT-PCR) assay. The feature of circ_FBLN1 was investigated by RNase R and Actinomycin D assays. Cell proliferation ability was evaluated by colony formation assay and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The targeting relationship between let-7i-5p and circ_FBLN1 or FZD4 was verified by dual-luciferase reporter assay. Circ_FBLN1 level was enhanced during the osteogenic differentiation of hBMSCs. Silencing of circ_FBLN1 repressed cell proliferation and osteogenic differentiation in hBMSCs. For mechanism analysis, circ_FBLN1 was found to act as a sponge for let-7i-5p and FZD4 served as a direct target gene of let-7i-5p. Let-7i-5p was downregulated during the osteogenic differentiation of hBMSCs and let-7i-5p inhibition restored the effects of circ_FBLN1 knockdown on the proliferation and osteogenesis of hBMSCs. Moreover, let-7i-5p overexpression suppressed cell proliferation and osteogenesis in hBMSCs through targeting FZD4. In addition, circ_FBLN1 knockdown reduced the levels of Wnt6 and β-catenin in hBMSCs, indicating the inactivation of Wnt/β-catenin pathway. Knockdown of circ_FBLN1 inhibited the proliferation and osteogenesis of hBMSCs by regulating let-7i-5p/FZD4 axis and repressing Wnt/β-catenin pathway.

Zhang Z ，Zhou H ，Sun F ，Han J ，Han Y ... -  《-》

The osteogenic differentiation of human adipose-derived stem cells is regulated through the let-7i-3p/LEF1/β-catenin axis under cyclic strain.

Luo Y ，Ge R ，Wu H ，Ding X ，Song H ，Ji H ，Li M ，Ma Y ，Li S ，Wang C ，Du H ... -  《Stem Cell Research & Therapy》

miR-139-5p Represses BMSC Osteogenesis via Targeting Wnt/β-Catenin Signaling Pathway.

Long H ，Sun B ，Cheng L ，Zhao S ，Zhu Y ，Zhao R ，Zhu J ... -  《-》

Circ_0067680 expedites the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells through miR-4429/CTNNB1/Wnt/β-catenin pathway.

Human bone marrow-derived mesenchymal stem cells (hBMSCs) are the primary source of osteoblasts in vivo. Emerging literatures have unveiled that circular RNAs (circRNAs) are actively drawn in the osteogenic differentiation of mesenchymal stem cells (MSCs). This research mainly illuminated the role of circ_0067680 as well as its regulatory mechanism in osteoblastic differentiation. In this study, RT-qPCR was to measure the expression of circ_0067680. Functional assays were implemented to assess the role of circ_0067680 in osteogenic differentiation. Besides, RNA pull down, RIP and luciferase reporter assays were carried out to investigate the regulatory mechanism of circ_0067680. Circ_0067680, which derived from its host gene divergent protein kinase domain 2A (C3orf58), was up-regulated during osteogenic differentiation of hBMSCs. Besides, circ_0067680 deficiency impeded the osteoblastic differentiation of hBMSCs. Moreover, circ_0067680 served as a ceRNA via sequestering miR-4429 to regulate the expression of catenin beta 1 (CTNNB1), thereby activating the Wnt/β-catenin signaling pathway. Circ_0067680 accelerated hBMSCs osteogenic differentiation by the miR-4429/CTNNB1/Wnt/β-catenin signaling, which might be used as a potential biomarker for osteoblastic differentiation.

Huang Y ，Wan S ，Yang M 《Biology Direct》

CircRNA has_circ_0017109 promotes lung tumor progression via activation of Wnt/β-catenin signaling due to modulating miR-671-5p/FZD4 axis.

Accumulating evidence highlights the critical roles of circular RNAs (circRNAs) in the malignant progression of cancers. In this study, we investigated the expression pattern of a newly identified circRNA (hsa_circ_0017109) in non-small cell lung cancer (NSCLC), and examined its downstream molecular targets. Quantitative real-time PCR (qRT-PCR) and Western blotting (WB) were conducted to quantify gene and protein expression. In vitro functional assays such as colony formation assay, cell counting kit-8 (CCK-8) and flow cytometry were used to study cell proliferation and apoptosis. RNA pull-down assay, luciferase reporter assay and RNA immunoprecipitation were performed to validate molecular interaction. Mouse xenograft model of NSCLC cells was used to assess the role of circ_0017109 in tumorigenesis. Circ_0017109 was upregulated in NSCLC tumor samples and cells. Silencing circ_0017109 impaired cell proliferation and promoted apoptosis in NSCLC cells, and circ_0017109 knockdown suppressed in vivo tumorigenesis of NSCLC cells in mouse xenograft model. MiR-671-5p was identified as a target of circ_0017109, and circ_0017109 negatively impacted on miR-671-5p expression. MiR-671-5p downregulated FZD4 and dampened the activity of Wnt/β-catenin signaling pathway. Circ_0017109 modulated FZD4 expression by suppressing miR-671-5p activity. Elevated circ_0017109 expression promotes tumor progression of NSCLC by modulating miR-671-5p/FZD4/β-catenin axis.

Yang B ，Zhang B ，Qi Q ，Wang C ... -  《BMC Pulmonary Medicine》