An in vitro model of osteogenesis was established by treating MC3T3‐E1 murine preosteoblast cells with BMP2. MiR‐17‐3p inhibited the differentiation of MC3T3‐E1 cells. Sox6 was confirmed to be a target gene of miR‐17‐3p, and the inhibitory effect of miR‐17‐3p on osteoblast differentiation was reversed by Sox6. These results suggest potential implications for the treatment of orthopedic disorders.

Keywords: MC3T3‐E1, miR‐17‐3p, osteoblast, Sox6
Abstract
Osteoporosis and osteoarthritis are orthopedic disorders that affect millions of elderly people worldwide; stimulation of bone formation is a potential therapeutic strategy for the treatment of these conditions. As the only bone‐forming cells, osteoblasts play a key role in bone reconstruction. The microRNA miR‐17‐3p is downregulated during osteogenic differentiation of human bone marrow mesenchymal stem cells, but its precise role in this process is unknown. Here, we investigated the role of miR‐17‐3p in osteoblast differentiation. An in vitro model of osteogenesis was established by treating MC3T3‐E1 murine preosteoblast cells with bone morphogenetic protein 2 (BMP2). The expression of miR‐17‐3p in BMP2‐induced MC3T3‐E1 cells was detected by reverse transcription‐quantitative PCR, and its effects on cells transfected with miR‐17‐3p mimic or inhibitor were evaluated by Alizarin Red staining, alkaline phosphatase (ALP) activity assay, and by detection of osteoblast markers including the ALP, collagen type I α1 chain, and osteopontin genes. Bioinformatics analysis was carried out to identify putative target genes of miR‐17‐3p, and the luciferase reporter assay was used for functional validation. Rescue experiments were performed to determine whether SRY‐box transcription factor 6 (Sox6) plays a role in the regulation of osteoblast differentiation by miR‐17‐3p. We report that miR‐17‐3p was downregulated upon BMP2‐induced osteoblast differentiation in MC3T3‐E1 cells, and this was accompanied by decreased differentiation and mineralization, ALP activity, and expression of osteogenesis‐related genes. Sox6 was confirmed to be a target gene of miR‐17‐3p in osteoblasts, and the inhibitory effect of miR‐17‐3p on osteoblast differentiation was observed to occur via Sox6. These results suggest the existence of a novel mechanism underlying miRNA‐mediated regulation of osteogenesis, which has potential implications for the treatment of orthopedic disorders.
Abbreviations
- ALP
alkaline phosphatase
- BMP2
bone morphogenetic protein 2
- COLIA1
collagen type I α1 chain
- GAPDH
glyceraldehyde‐3‐phosphate dehydrogenase
- miR‐17‐3p
microRNA‐17‐3p
- miRNA
microRNA
- MUT
mutation‐type
- NC
negative control
- OPN
osteopontin
- RT‐qPCR
reverse transcription‐quantitative PCR
- SD
standard deviation
- SiRNA
Small interfering RNA
- Sox6
SRY‐box transcription factor 6
- UTR
untranslated region
- WT
wild‐type
Osteoporosis and osteoarthritis are orthopedic disorders that affect millions of elderly people worldwide and are characterized by bone nonunion, loss, and defects that lead to impaired bone formation and bone deterioration [1]. Stimulating bone formation is a potential therapeutic strategy for the treatment of these conditions. As the only bone‐forming cells, osteoblasts play a key role in bone reconstruction [2]. Bone formation involves the differentiation of progenitor cells into osteoblasts; inhibiting this process can have pathologic consequences [3]. Osteogenic induction increases the expression of osteogenesis‐related genes including osteopontin (OPN), collagen type I α1 chain (COLIA1), and alkaline phosphatase (ALP) [4], which is a key event in osteoblast differentiation.
MicroRNAs (miRNAs) regulate a variety of cellular processes, and their dysregulation has been implicated in several diseases. Their activity mainly involves binding to the 3′ untranslated region (UTR) of target transcripts to alter gene expression [5, 6]. The role of miRNAs in osteogenesis and bone development has been widely investigated. Multiple miRNAs including miR‐138, miR‐2861, and miR‐148b have been shown to modulate the development of bone precursor cells [7, 8, 9]. MiR‐17‐3p is downregulated during osteogenic differentiation of human bone marrow mesenchymal stem cells [10], but its precise role in this process is unknown.
Transcription factors such as Runt‐related transcription factor 2 (Runx2), Osterix, mothers against DPP homolog 1 (SMAD), T‐cell factor (TCF)/Lymphoid enhancer‐binding factor (LEF), nuclear factor of activated T‐cell cytoplasmic 1 (NFATc1), Twist, activator protein 1 (AP‐1), and activating transcription factor 4 (ATF4) are known to play an important role in osteogenic differentiation [11, 12]. The transcription factor SRY‐box transcription factor 6 (Sox6) is involved in the differentiation of various tissues [13]. It was previously reported that Sox6 is a tumor suppressor gene that is downregulated in osteosarcoma (OS) tissues and cell lines. Osteogenic differentiation defects promote the development of OS; therefore, stimulating this process is a potential treatment strategy [14].
Based on the above findings, the present study investigated the roles of miR‐17‐3p and Sox6 in osteoblast differentiation in order to assess their potentiality as therapeutic targets in the treatment of bone disorders.
Materials and methods
Cell culture
MC3T3‐E1 murine preosteoblast cells were obtained from ScienCell (Carlsbad, CA, USA) and cultured in α‐minimal essential medium supplemented with 10% fetal bovine serum, penicillin (100 U·mL−1), and streptomycin (100 Ig·mL−1) at 37 °C and 5% CO2. Cells in passages 2 and 3 were used for experiments. To induce osteoblast differentiation, the cells were cultured in medium containing 200 ng·mL−1 BMP2 for 21 days.
Transfection of MC3T3‐E1 cells
MiR‐17‐3p mimic and miR‐17‐3p inhibitor, along with small interfering RNA (siRNA) targeting Sox6 or a scrambled control siRNA, were synthesized by GenePharma (Shanghai, China). The plasmids were transfected into MC3T3‐E1 cells at a concentration of 10 nm using Lipofectamine RNAiMAX transfection reagent (cat. no. 13‐778‐075; Invitrogen, Carlsbad, CA, USA) according to the manufacturer’s protocol.
Real‐time quantitative PCR
After osteoinduction of MC3T3‐E1 cells for 0, 1, 3, 7, 14, and 21 days, total RNA was extracted from cells using TRIzol reagent (GenePharma). cDNA was synthesized from 500 ng total RNA using the Bestar qPCR RT kit (DBI Bioscience, Shanghai, China), and 20–100 ng of cDNA served as the template for RT‐qPCR using Bestar SybrGreen qPCR Master Mix (DBI Bioscience) according to the manufacturer’s protocol. MiR‐17‐3p and Sox6 levels and the transfection efficiency of miR‐17‐3p mimic or inhibitor in MC3T3‐E1 cells were determined by RT‐qPCR. The expression of osteogenic differentiation‐related genes was also detected by RT‐qPCR in 3 independent experiments. Primers used for RT‐qPCR are shown in Table 1. U6 and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) served as internal controls for miRNA and mRNA, respectively. Relative expression levels of target genes were calculated with the 2−ΔΔCt method, with GAPDH level used for normalization.
Table 1.
All primers used in qPCR.
| Gene | Gene ID | Transcript ID | Forward primer (5'‐3') | Reverse primer (5'‐3') | Loci | Transcript length | Amplification length | Annealing temperature |
|---|---|---|---|---|---|---|---|---|
| Sox6 | 20679 | NM_011445.4 | GAGCCCAGGTTTGTCTCCATC | CCAGCGAGGAAGAGAAATTGC | 6122–6334 | 8715 | 213 | 54.9, 55.5 |
| ALP | 11647 | NM_007431.3 | CTACGCACCCTGTTCTGAGG | GGCCAAAGGGCAATAACTAG | 1801–2020 | 2524 | 220 | 52.2, 50.9 |
| COLIA1 | 12842 | NM_007742.4 | GAAGCTTGGTCCTCTTGCTTG | CATTGCCTTTGTTTGCTGGG | 4783–4980 | 5946 | 198 | 53.3, 55.5 |
| OPN | 20750 | NM_001204201.1 | GGACTGAGGTCAAAGTCTAGGAG | GGAATGCTCAAGTCTGTGTG | 606–839 | 1475 | 234 | 50.7, 47.6 |
| GAPDH | 14433 | NM_001289726.1 | CATCATCCCTGCATCCACTG | CAACCTGGTCCTCAGTGTAG | 701–930 | 1296 | 230 | 53.4, 46.7 |
| miR‐17‐3P | 723905 | MI0000687 | GCTCTGAUGUUCACGGAAGUG | GTGCAGGGTCCGAGGT | 51–72 | 84 | 70 | 52.2, 47.7 |
| U6 | 19862 | NR_003027.2 | CTCGCTTCGGCAGCACATATAC | GGAACGCTTCACGAATTTGC | 4– | 107 | 96 | 56.4, 54.7 |
Western blot analysis
Total protein was extracted using radioimmunoprecipitation assay buffer (pH 7.4) and separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis on a 10% gel. The proteins were transferred over 2 h to a nitrocellulose membrane (Millipore, Billerica, MA, USA) that was then blocked with 5% low‐fat milk at room temperature for 2 h and incubated overnight with a primary antibody against Sox6 (1:1000, cat. no. ab66316; Abcam, Cambridge, MA, USA), followed by horseradish peroxidase‐conjugated secondary antibody (1 : 5000, goat anti‐rabbit IgG H&L, cat. no. ab205718; Abcam) for 2 h at room temperature. Protein bands were detected with enhanced chemiluminescent reagent (Amersham Biosciences, Piscataway, NJ, USA). GAPDH was used as the loading control.
ALP activity and Alizarin Red staining
ALP activity was detected to assess the degree of differentiation of MC3T3‐E1 cells. After transfecting BMP2‐treated MC3T3‐E1 cells with miR‐17‐3p mimic or inhibitor or siRNA, ALP activity was determined using a commercial assay kit (Jiancheng Biotech, Nanjing, China), with absorbance measured at 405 nm. Calcification in MC3T3‐E1 cells was also detected by staining with Alizarin Red for 30 min at room temperature, and the absorbance was measured at 540 nm using a microplate reader. Images of stained cells were acquired on a light microscope.
Plasmid construction and dual‐luciferase activity assay
Sox6 was predicted as a target gene of miR‐17‐3p using TargetScan (http://www.targetscan.org/vert_72/). The fragment of Sox6 containing miR‐17‐3p binding sites was amplified by PCR with specific primers and cloned into the psi‐CHEK2 vector (Promega, Madison, WI, USA) to obtain wild‐type (WT) Sox6 plasmid. A fragment containing mutated miR‐17‐3p‐binding sites was also amplified and inserted into psi‐CHEK2 to generate the mutant (MUT) Sox6 plasmid. WT and MUT Sox6 3′ UTR DNA sequences were synthesized by GenePharma. MC3T3‐E1 cells incubated overnight in 24‐well plates were cotransfected with WT or MUT Sox6 plasmid and miR‐17‐3p mimic or negative control (NC) using Lipofectamine 2000 (Invitrogen). Luciferase activity was determined with the Dual‐Luciferase Reporter Assay System (Promega) according to the manufacturer’s instructions, with absorbance measured at 560 nm.
Statistical analysis
Statistical analysis was performed using prism v5.0 software (GraphPad, La Jolla, CA, USA). All data are presented as mean ± standard deviation (SD). Differences between groups were evaluated with the Wilcoxon test. The experiments were carried out independently three times. P < 0.05 was considered statistically significant.
Results
MiR‐17‐3p is downregulated during BMP2‐induced osteoblast differentiation
MiR‐17‐3p expression levels in MC3T3‐E1 cells on days 0, 1, 3, 7, 14, and 21 of osteoblast differentiation were determined by RT‐qPCR. MiR‐17‐3p expression decreased over time in BMP2‐treated cells compared to the untreated control group (Fig. 1A). In MC3T3‐E1 cells transfected with miR‐17‐3p mimic or inhibitor, miR‐17‐3p level was higher and lower, respectively, than in cells transfected with NC, which confirmed the efficiency of transfection (Fig. 1B).
Fig. 1.

MiR‐17‐3p is downregulated during osteoblast differentiation. (A, B) miR‐17‐3p level in BMP2‐treated MC3T3‐E1 cells (A) and cells transfected with miR‐17‐3p mimic or inhibitor for 24 h (B), as determined by RT‐qPCR. The error bars indicate SD. Wilcoxon test was used to evaluate the differences between groups. n = 3, *P < 0.05, **P < 0.0, ## P < 0.01.
MiR‐17‐3p attenuates osteoblast differentiation
To examine the role of miR‐17‐3p in osteoblast differentiation, miR‐17‐3p mimic or inhibitor was transfected into MC3T3‐E1 cells following BMP2 induction. Overexpression of miR‐17‐3p significantly reduced calcification compared to BMP2‐treated NC‐transfected control cells, whereas inhibition of miR‐17‐3p had the opposite effect. Similar trends were observed for mineralization (Fig. 2A,B). Furthermore, compared to cells with BMP2 treatment, ALP activity was decreased in BMP2‐induced cells transfected with miR‐17‐3p mimic and increased in those transfected with miR‐409‐3p inhibitor (Fig. 2C), with corresponding decreases or increases in the expression levels of the osteoblast marker genes ALP, COLIA1, and OPN (Fig. 2D). These results confirm that miR‐17‐3p inhibits BMP2‐induced osteoblast differentiation in MC3T3‐E1 cells.
Fig. 2.

MiR‐17‐3p suppresses osteoblast differentiation in MC3T3‐E1 cells. Cells were transfected with miR‐17‐3p mimic or inhibitor and treated with 200 ng·mL−1 BMP2 for 14 days. Transfected cells without BMP treatment or without transfection but treated with BMP2 served as negative controls. (A) Calcification in cells detected by Alizarin Red staining, the length of the scale bars is 200 μm. (B) Matrix mineralization was evaluated by Alizarin Red staining. (C) ALP activity detected with a commercial assay kit. (D) mRNA levels of osteoblast marker genes (ALP, COLIA1, and OPN) determined by RT‐qPCR. The error bars indicate SD. Wilcoxon test was used to evaluate the differences between groups. n = 3, **P < 0.01, ***P < 0.001; # P < 0.05, ## P < 0.01.
Sox6 is a target gene of miR‐17‐3p
The TargetScan prediction algorithm identified putative miR‐17‐3p‐binding sites in the Sox6 3' UTR (Fig. 3A). We found that luciferase activity was reduced in MC3T3‐E1 cells cotransfected with miR‐17‐3p mimic and Sox6 WT 3' UTR compared to those that were cotransfected with NC mimic + Sox6 WT 3' UTR, whereas an increase in activity was observed in cells cotransfected with miR‐17‐3p inhibitor + Sox6 MUT 3' UTR. On the other hand, there was no change in luciferase activity in cells cotransfected with miR‐17‐3p mimic or inhibitor and Sox6 MUT 3' UTR (Fig. 3B). Furthermore, in cells transfected with miR‐17‐3p mimic, Sox6 mRNA and protein levels were markedly reduced compared to cells transfected with NC mimic, as determined by RT‐qPCR and western blotting, respectively (Fig. 3C,D). These results demonstrate that Sox6 expression in osteoblast differentiation is regulated by miR‐17‐3p.
Fig. 3.

Sox6 is a target gene of miR‐17‐3p in osteoblasts. (A) Sequence alignment of seed‐matched binding sites for miR‐17‐3p in the Sox6 3' UTR. (B) Effect of miR‐17‐3p on luciferase activity in MC3T3‐E1 cells transfected with the Sox6 3' UTR luciferase reporter detected 48‐h transfection. (C, D) Sox6 mRNA (C) and protein (D) levels determined by RT‐qPCR and western blotting, respectively, following transfection with miR‐17‐3p mimic or miR‐17‐3p inhibitor for 24 h. The error bars indicate SD. Wilcoxon test was used to evaluate the differences between groups. n = 3, **P < 0.01, ***P < 0.001; ## P < 0.01.
Sox6 knockdown reverses the inhibition of osteoblast differentiation by miR‐17‐3p
To examine the relationship between miR‐17‐3p and Sox6 in greater detail, we cotransfected miR‐17‐3p inhibitor and Sox6 siRNA into MC3T3‐E1 cells for 24 h, followed by BMP2 treatment for 14 days to induce osteoblast differentiation. Sox6 knockdown decreased the level of Sox6 in cells transfected with miR‐17‐3p inhibitor compared to those transfected with NC or miR‐17‐3p inhibitor + scrambled siRNA (Fig. 4A). Additionally, Sox6 depletion reduced mineralization in the miR‐17‐3p inhibitor group compared with the miR‐17‐3p inhibitor + scrambled siRNA group (Fig. 4B). Similar trends were observed for ALP activity and ALP, COLIA1, and OPN mRNA levels (Fig. 4C,D). Thus, miR‐17‐3p inhibits osteoblast differentiation via negative regulation of Sox6 expression.
Fig. 4.

Sox6 knockdown reverses the effects of miR‐17‐3p inhibition on osteoblast differentiation. MC3T3‐E1 cells were cotransfected with miR‐17‐3p inhibitor and Sox6 siRNA for 24 h, followed by induction of osteoblast differentiation by BMP2 treatment for 14 days. (A) Relative expression level of Sox6 protein. (B) Matrix mineralization evaluated by Alizarin Red staining. (C) ALP activity detected with a commercial assay kit. (D) mRNA levels of osteoblast marker genes (ALP, COLIA1, and OPN) determined by RT‐qPCR. The error bars indicate SD. Wilcoxon test was used to evaluate the differences between groups. n = 3, *P < 0.05, **P < 0.01; # P < 0.05, ## P < 0.01.
Discussion
In the present study, we observed that miR‐17‐3p expression decreased during BMP2‐induced osteoblast differentiation in MC3T3‐E1 cells. Gain‐ and loss‐of‐function experiments using miR‐17‐3p mimic or inhibitor, respectively, showed that miR‐17‐3p suppressed mineralization, ALP activity, and the expression of osteogenesis‐associated genes (ALP, Col1A1, and OPN). We also confirmed that miR‐17‐3p directly regulates Sox6 expression in MC3T3‐E1 cells during osteoblast differentiation. These data provide evidence for miR‐17‐3p as a negative regulator of osteogenesis that acts by inhibiting Sox6 and its downstream targets.
Osteoblasts are essential for maintaining the stability of the intraosseous environment. Multiple miRNAs have been identified that participate in osteoblast differentiation. For example, miR‐29b, miR‐210, miR‐335‐5p, and miR‐2861 were shown to enhance this process [15, 16, 17, 18], whereas miR‐125a‐3p, miR‐145‐5p, miR‐106b‐5p, and miR‐17‐5p exert suppressive effects [19, 20, 21]. MiR‐17‐3p is variably expressed in different cancer types [22, 23, 24] but its role in osteogenesis has not been previously reported. The MC3T3‐E1 preosteoblast cell line has been widely used for in vitro studies of osteogenesis. We used these cells in the present study to investigate the mechanism by which miR‐17‐3p regulates osteoblast differentiation. Interestingly, the miR‐17‐92 cluster has been shown to regulate bone growth and development; as a mature miRNA within this cluster, miR‐17‐3p has been suggested to play an essential role in bone formation [25], which is supported by the current findings.
MiRNAs mainly act by modulating the expression of target transcripts. Numerous miRNAs are known to participate in osteogenesis either as positive or negative regulators [26]. Sox6 encodes a transcription factor that is involved in the differentiation of various cell types including mesenchymal stem cells and neurons [14, 27, 28]. OS, which is common in children and adolescents, is characterized by impaired bone formation resulting from abnormal osteogenesis [29]. Sox6 was shown to suppress proliferation, invasion, and epithelial‐to‐mesenchymal transition in OS cells by targeting TWIST1 [14]. Reduced differentiation and loss of function of osteoblasts are key features of osteoporosis and osteoarthritis. A large‐scale meta‐analysis identified Sox6 as a candidate gene that increased bone mineral density and thereby improved osteoporosis in women [30]. Sox6 and Sox9 are also important factors in cartilage homeostasis that stimulate cartilage formation, which may promote bone growth and prevent osteoarthritis [31]. In our study, we found that miR‐17‐3p suppressed osteoblast differentiation by downregulating the expression of Sox6, although the clinical significance of this observation in the context of OS or osteoporosis remains to be determined. Additionally, the detailed mechanism of Sox6 regulation by miR‐17‐3p in osteogenesis warrants further study, although there is evidence suggesting that Sox6 specifically activates enhancers of target genes in primary osteoblasts [32].
In conclusion, the results of our study demonstrate for the first time that miR‐17‐3p negatively regulates osteoblast differentiation by suppressing Sox6 expression. Thus, therapeutic strategies that inhibit miR‐17‐3p could potentially stimulate bone formation and may be an effective treatment for OS and orthopedic disorders such as osteoporosis and osteoarthritis.
Conflict of interest
The authors confirm that they have no financial or non‐financial conflicts of interest.
Author contribution
HY conceived and designed the entire study; NC and DW analyzed the data, performed literature research, and drafted the paper. HL and YL were responsible for data analysis and visualization. HY guided the entire study and revised it critically for important intellectual content. All authors have read and agreed with the final version of this manuscript.
Acknowledgements
The present study was supported by the Yunnan Scientific and Technology Committee and Kunming Medical University (Kunming, China) [Grant No.: 2018FE001(‐199)]. We acknowledge and appreciate Dr. Ge Zhu (Changhai Hospital of Second Military Medical University) for his valuable efforts and constructive comments on this manuscript.
Data Availability Statement
Data will be available from the corresponding author upon reasonable request.
References
- 1. Dong S, Yang B, Guo H and Kang F (2012) MicroRNAs regulate osteogenesis and chondrogenesis. Biochem Biophys Res Commun 418, 587–591. [DOI] [PubMed] [Google Scholar]
- 2. Corrado A, Sanpaolo ER, Di Bello S and Cantatore FP (2017) Osteoblast as a target of anti‐osteoporotic treatment. Postgrad Med 129, 858–865. [DOI] [PubMed] [Google Scholar]
- 3. Raggatt LJ and Partridge NC (2010) Cellular and molecular mechanisms of bone remodeling. J Biol Chem 285, 25103–25108. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Adamzyk C, Kachel P, Hoss M, Gremse F, Modabber A, Holzle F, Tolba R, Neuss S and Lethaus B (2016) Bone tissue engineering using polyetherketoneketone scaffolds combined with autologous mesenchymal stem cells in a sheep calvarial defect model. J Craniomaxillofac Surg 44, 985–994. [DOI] [PubMed] [Google Scholar]
- 5. Bartel DP (2009) MicroRNAs: target recognition and regulatory functions. Cell 136, 215–233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Eric H and Izaurralde E (2011) Gene silencing by microRNAs: contributions of translational repression and mRNA decay. Nat Rev Genet 12, 99–110. [DOI] [PubMed] [Google Scholar]
- 7. Eskildsen T, Taipaleenmäki H, Stenvang J, Abdallah BM, Ditzel N, Nossent AY, Bak M, Kauppinen S and Kassem M (2011) MicroRNA‐138 regulates osteogenic differentiation of human stromal (mesenchymal) stem cells in vivo [Cell Biology]. Proc Natl Acad Sci U S A 108, 6139–6144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Li H, Xie H, Liu W, Hu R, Huang B, Tan YF, Xu K, Sheng ZF, Zhou HD, Wu XP and et al, (2009) A novel microRNA targeting HDAC5 regulates osteoblast differentiation in mice and contributes to primary osteoporosis in humans. J Clin Invest 119, 3666–3677. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Schoolmeesters A, Eklund T, Leake D, Vermeulen A, Smith Q, Aldred SF and Fedorov Y (2009) Functional profiling reveals critical role for miRNA in differentiation of human mesenchymal stem cells. PLoS One 4, e5605. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Baglìo SR, Devescovi V, Granchi D and Baldini N (2013) MicroRNA expression profiling of human bone marrow mesenchymal stem cells during osteogenic differentiation reveals Osterix regulation by miR‐31. Gene 527, 321–331. [DOI] [PubMed] [Google Scholar]
- 11. Deng ZL, Sharff KA, Tang N, Song WX, Luo JY, Luo XJ, Chen J, Bennett E, Reid R, Manning D et al, (2008) Regulation of osteogenic differentiation during skeletal development. Front Biosci 13, 2001–2021. [DOI] [PubMed] [Google Scholar]
- 12. Karsenty G (2003) The complexities of skeletal biology. Nature 423, 316–318. [DOI] [PubMed] [Google Scholar]
- 13. Zou L, Zou X, Li H, Mygind T, Zeng Y, Lü N and Bünger C (2006) Molecular mechanism of osteochondroprogenitor fate determination during bone formation. Adv Exp Med Biol 585, 431–441. [DOI] [PubMed] [Google Scholar]
- 14. Wang Z, Li J, Li K and Xu J (2018) SOX6 is downregulated in osteosarcoma and suppresses the migration, invasion and epithelial‐mesenchymal transition via TWIST1 regulation. Mol Med Rep 17, 6803–6811. [DOI] [PubMed] [Google Scholar]
- 15. Hu R, Liu W, Li H, Yang L, Chen C, Xia ZY, Guo LJ, Xie H, Zhou HD, Wu XP et al, (2011) A Runx2/miR‐3960/miR‐2861 regulatory feedback loop during mouse osteoblast differentiation. J Biol Chem 286, 12328–12339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16. Zhang J, Tu QS, Bonewald LF, He X, Stein G, Lian J and Chen J (2011) Effects of miR‐335‐5p in modulating osteogenic differentiation by specifically downregulating Wnt antagonist DKK1. J Bone Miner Res 26, 1953–1963. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Mizuno Y, Tokuzawa Y, Ninomiya Y, Yagi K, Yatsuka‐Kanesaki Y, Suda T, Fukuda T, Katagiri T, Kondoh Y, Amemiya T et al, (2009) miR‐210 promotes osteoblastic differentiation through inhibition of AcvR1b. FEBS Lett 583, 2263–2268. [DOI] [PubMed] [Google Scholar]
- 18. Li ZY, Hassan MQ, Jafferji M, Aqeilan RI, Garzon R, Croce CM, van Wijnen AJ, Stein JL, Stein GS and Lian JB (2009) Biological functions of miR‐29b contribute to positive regulation of osteoblast differentiation. J Biol Chem 284, 15676–15684. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19. Tu XM, Gu YL and Ren GQ (2016) miR‐125a‐3p targetedly regulates GIT1 expression to inhibit osteoblastic proliferation and differentiation. Exp Ther Med 12, 4099–4106. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20. Liu S, Gao G, Yan D, Chen X, Yao X, Guo S, Li G and Zhao Y (2017) Effects of miR‐145‐5p through NRAS on the cell proliferation, apoptosis, migration, and invasion in melanoma by inhibiting MAPK and PI3K/AKT pathways. Cancer Med 6, 819–833. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
- 21. Fang T, Wu Q, Zhou L, Mu S and Fu Q (2016) miR‐106b‐5p and miR‐17‐5p suppress osteogenic differentiation by targeting Smad5 and inhibit bone formation. Exp Cell Res 347, 74–82. [DOI] [PubMed] [Google Scholar]
- 22. Yang X, Du WW, Li H, Liu F, Khorshidi A, Rutnam ZJ and Yang BB (2013) Both mature miR‐17‐5p and passenger strand miR‐17‐3p target TIMP3 and induce prostate tumor growth and invasion. Nucleic Acids Res 41, 9688–9704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23. Asakura K, Kadota T, Matsuzaki J, Yoshida Y, Yamamoto Y, Nakagawa K, Takizawa S, Aoki Y, Nakamura E, Miura J et al, (2020) A miRNA‐based diagnostic model predicts resectable lung cancer in humans with high accuracy. Commun Biol 3, 134. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Shincy JS, Panagal M, Jereena J, Vengatagiri GY, Vittalrao KR, Sivakumar P, Gopinath V, Kumar KM and Sekar D (2017) Computational identification of microRNA‐17‐3p in breast cancer cells. MicroRNA (Shariqah, United Arab Emirates) 6, 208–212. [DOI] [PubMed] [Google Scholar]
- 25. Bai X, Hua S, Zhang J and Xu S (2019) The MicroRNA family both in normal development and in different diseases: the miR‐17‐92 cluster. BioMed Res Int 2019, 9450240. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Jia B, Zhang Z, Qiu X, Chu H, Sun X, Zheng X, Zhao J and Li Q (2018) Analysis of the miRNA and mRNA involved in osteogenesis of adipose‐derived mesenchymal stem cells. Exp Ther Med 16, 1111–1120. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27. Wang H, Shan XB, Qiao YJ, Wang H, Shan XB and Qiao YJ (2017) PDK2 promotes chondrogenic differentiation of mesenchymal stem cells by upregulation of Sox6 and activation of JNK/MAPK/ERK pathway. Braz J Med Biol Res 50, e5988. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
- 28. Hamadakanazawa M, Ogawa D, Takano M and Miyake M (2016) Sox6 suppression induces RA‐dependent apoptosis mediated by BMP‐4 expression during neuronal differentiation in P19 cells. Mol Cell Biochem 412, 49–57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29. Wagner ER, Luther G, Zhu G, Luo Q, Shi Q, Kim SH, Gao JL, Huang E, Gao Y, Yang K et al, (2011) Defective osteogenic differentiation in the development of osteosarcoma. Sarcoma 2011, 325238. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30. Hsu YH, Zillikens MC, Wilson SG, Farber CR, Demissie S, Soranzo N, Bianchi EN, Grundberg E, Liang L, Richards JB et al (2010) An integration of genome‐wide association study and gene expression profiling to prioritize the discovery of novel susceptibility Loci for osteoporosis‐related traits. PLoS Genet 6, e1000977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31. Liu CF and Lefebvre V (2015) The transcription factors SOX9 and SOX5/SOX6 cooperate genome‐wide through super‐enhancers to drive chondrogenesis. Nucleic Acids Res 43, 8183–8203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32. Kawane T, Komori H, Liu W, Moriishi T, Miyazaki T, Mori M, Matsuo Y, Takada Y, Izumi S, Jiang Q et al (2014) Dlx5 and mef2 regulate a novel runx2 enhancer for osteoblast‐specific expression. J Bone Miner Res 29, 1960–1969. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data will be available from the corresponding author upon reasonable request.
