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Research ArticleShared Genetic and Epigenetic Mechanisms between theOsteogenic Differentiation of Dental Pulp Stem Cells and BoneMarrow Stem Cells
Sebastian Gaus ,1 Hanluo Li ,1 Simin Li ,2 Qian Wang ,3 Tina Kottek ,1
Sebastian Hahnel ,1 Xiangqiong Liu ,4 Yupei Deng ,4 Dirk Ziebolz ,2 Rainer Haak ,2
Gerhard Schmalz ,2 Lei Liu ,5 Vuk Savkovic ,1 and Bernd Lethaus 1
1Department of Cranio Maxillofacial Surgery, University Clinic Leipzig, Liebigstr. 12, Leipzig 04103, Germany2Department of Cariology, Endodontology and Periodontology, University Leipzig, Liebigstr. 12, Leipzig 04103, Germany3Department of Central Laboratory, Taian Central Hospital, Longtan Road No. 29, Taian, 271000 Shandong Province, China4Department of Molecular Cell Biology, Beijing Tibetan Hospital, China Tibetology Research Center, 218 Anwaixiaoguanbeili Street,Chaoyang, Beijing 100029, China5Department of Neurology, Shandong Provincial Third Hospital, Cheeloo Chollege of Medicine, Shandong University, Jinan,100191 Shandong Province, China
Correspondence should be addressed to Vuk Savkovic; [email protected]
Received 29 November 2020; Revised 4 January 2021; Accepted 20 January 2021; Published 8 February 2021
Academic Editor: Min Tang
Copyright © 2021 Sebastian Gaus et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Objective. To identify the shared genetic and epigenetic mechanisms between the osteogenic differentiation of dental pulp stem cells(DPSC) and bone marrow stem cells (BMSC).Materials and Methods. The profiling datasets of miRNA expression in the osteogenicdifferentiation of mesenchymal stem cells from the dental pulp (DPSC) and bone marrow (BMSC) were searched in the GeneExpression Omnibus (GEO) database. The differential expression analysis was performed to identify differentially expressedmiRNAs (DEmiRNAs) dysregulated in DPSC and BMSC osteodifferentiation. The target genes of the DEmiRNAs that weredysregulated in DPSC and BMSC osteodifferentiation were identified, followed by the identification of the signaling pathways andbiological processes (BPs) of these target genes. Accordingly, the DEmiRNA-transcription factor (TFs) network and theDEmiRNAs-small molecular drug network involved in the DPSC and BMSC osteodifferentiation were constructed. Results. 16dysregulated DEmiRNAs were found to be overlapped in the DPSC and BMSC osteodifferentiation, including 8 DEmiRNAs with acommon expression pattern (8 upregulated DEmiRNAs (miR-101-3p, miR-143-3p, miR-145-3p/5p, miR-19a-3p, miR-34c-5p,miR-3607-3p, miR-378e, miR-671-3p, and miR-671-5p) and 1 downregulated DEmiRNA (miR-671-3p/5p)), as well as 8DEmiRNAs with a different expression pattern (i.e., miR-1273g-3p, miR-146a-5p, miR-146b-5p, miR-337-3p, miR-382-3p, miR-4508, miR-4516, and miR-6087). Several signaling pathways (TNF, mTOR, Hippo, neutrophin, and pathways regulatingpluripotency of stem cells), transcription factors (RUNX1, FOXA1, HIF1A, and MYC), and small molecule drugs (curcumin,docosahexaenoic acid (DHA), vitamin D3, arsenic trioxide, 5-fluorouracil (5-FU), and naringin) were identified as commonregulators of both the DPSC and BMSC osteodifferentiation. Conclusion. Common genetic and epigenetic mechanisms areinvolved in the osteodifferentiation of DPSCs and BMSCs.
1. Introduction
Repairing bone defects remains a challenge for clinical prac-titioners to the present day. For the last decades, autologousbone transplantation has been a “gold standard” for treating
bone defects in the dental field, such as insufficient bone vol-ume for dental implants and maxillofacial defects [1, 2].Nonetheless, the conventional treatment involves drawbackssuch as donor site morbidity and limitation of bone volume[3], which calls for alternative approaches. Mesenchymal
HindawiBioMed Research InternationalVolume 2021, Article ID 6697810, 25 pageshttps://doi.org/10.1155/2021/6697810
stem cells appear to be a good match to the unmet needs ofthe conventional autologous bone transplantation. They arecapable of acting in paracrine anti-inflammatory and trophicfashion, as well as of providing a cellular base for tissuereplacement by virtue of their self-renewal and multilineagedifferentiation capacity [4]. The most commonly used MSCsare bone marrow stem cells (BMSCs), dental pulp stem cells(DPSCs), and adipose tissue stem cells (ADSCs). BMSCshave been the most commonly used type of stem cells forosteogenesis and new bone formation due to their tissue ori-gin; however, BMSCs are obtained by means of invasive andpainful bone marrow aspiration [5]. This downside hasinspired the use of other less invasively obtained stem celltypes. Among those, DPSCs obtained from the extractedthird molar present a highly accessible alternative [6]. Inaddition, DPSCs have been demonstrated as highly capableof osteogenic differentiation under osteogenesis-inducingconditions [7], and they are therefore becoming a valuablealternative approach for transplantation-based bone regener-ation [8]. Nevertheless, critical preclinical data necessary forunderstanding the genetic and epigenetic mechanismsinvolved in the osteogenic differentiation of DPSCs andBMSCs are still modestly represented.
Stem cells derived from different tissues tend to respondto the same stimulus differently and differentiate towardsthe tissue of their origin [9]. Accordingly, BMSCs display ahigh predisposition to progress towards osteogenic differen-tiation [9]. It has been shown that the osteogenic differenti-ation capacity of the BMSCs is higher than that of ADSCs[10, 11] and comparable between the BMSCs and DPSCs[12]. Having tremendous BMSCs and DPSCs osteogenicpotential at disposal, it is necessary to gain a fuller under-standing of genetic and epigenetic processes that underlietheir differentiation capacity in order to utilize their osteo-genic ability.
Many genetic and epigenetic factors are involved in theosteogenic differentiation of stem cells, such as messengerRNAs (mRNAs), microRNAs (miRNAs), and signalingpathways. As a significant component of the epigeneticmodification, miRNAs are classified as short noncodingRNAs which can inhibit the expression of mRNAs by bind-ing the 3′-untranslated region (UTR) of target mRNAs [13,14]. The aberrant expression of many miRNAs (e.g., miR-16, miR-381, miR-20a, and miR-214) has been involved inthe osteogenic differentiation of stem cells by inducing thedysregulation of osteogenesis-related signaling pathways(e.g., Wnt, BMP, MAPK, RUNX2, and Notch pathways)[15–22]. Although some research using RNA-sequencingtechnique have investigated the miRNA expression alter-ations during the osteodifferentiation process of BMSCs[23] and DPSCs [24], respectively, there is still no reportwhich is aimed on identifying the genetic and epigeneticbiomarkers shared between the osteogenic differentiationof both types of stem cells.
The present study is aimed at identifying the overlappinggenetic and epigenetic mechanisms involved in the osteo-genic differentiation of DPSC and BMSC. To this purpose,a series of bioinformatics analyses (e.g., differential expres-sion analysis, DEmiRNA-target gene network construction,
DEmiRNA-transcription factor construction, and functionalenrichment analysis) were performed to investigate themajor common genetic and epigenetic mechanisms of DPSCosteogenesis and BMSC osteogenesis.
2. Materials and Methods
2.1. Data Acquisition. The miRNA expression profiling data-sets regarding the osteogenic differentiation of DPSC andBMSC were searched for in the Gene Expression Omnibus(GEO) database of NCBI [25]. The following inclusion cri-teria were defined for analyzing two study groups: an undif-ferentiated control group nominated as the day zero ofdifferentiation (d0), and the experimental group examinedafter differentiation on day 14, with matched examinationdays for the DPSC and BMSC experimental group (d14).The datasets with a sample size of more than three for eachgroup were included.
2.2. Analyzing Processes of the Present Research. Two datasets(GSE138180 and GSE107279), which investigated themiRNA expression profile of DPSC and BMSC, were selectedfor assessment. After selecting the corresponding datasets, aseries of bioinformatics analyses were performed accordingto the flowchart of this study (Figure 1).
Firstly, the differential expression analysis was per-formed to identify the DEmiRNAs which were aberrantlyexpressed during the osteodifferentiation process of DPSCsand BMSCs, in order to identify the overlapping DEmiR-NAs. Subsequently, the target genes of these commonDEmiRNAs that were singled out in the first step wereidentified by constructing a target gene network of 16overlapping DEmiRNAs. Furthermore, target genes ofDEmiRNAs involved in the DPSC osteogenesis and BMSCosteogenesis were, respectively, extracted by searchingmiRNA-target interaction databases. The functions (i.e., bio-logical processes and signaling pathways) of these targetgenes were identified by the means of functional enrichmentanalysis. In addition, transcription factors that potentiallytarget the DEmiRNAs were identified by constructing theDEmiRNAs-transcription factor interaction network. Con-clusively, the DEmiRNAs-small molecular drug targetsnetwork was constructed in order to identify the smallmolecular drugs that can influence the expression of DEmiR-NAs involved in DPSC and BMSC osteodifferentiation.
2.3. Differential Expression Analysis for IdentifyingDEmiRNAs. Differential expression analysis (DEA) was usedto identify the differentially expressed miRNAs (DEmiRNAs)of the two selected datasets. DEA was performed by usingdifferent packages in the R program depending on the differ-ent experimental types of datasets. The limma package wasused to analyze continuous data such as microarray data,whereas the edgeR/DESeq/DESeq2 was used for count datasuch as high-throughput sequencing. The experimental typeof the GSE138180 dataset presents the noncoding RNA pro-file analyzed by the means of microarray, whereas the exper-imental type of the GSE107279 dataset profiling of thenoncoding RNA has been attained by high-throughput
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sequencing. Based on this, the DEA of the GSE138180 data-set was carried out using the limma package of the Rprogram version 3.6.1 [26], whereas the DEA of theGSE107279 dataset was performed by using the DESeq2package [27]. The miRNAs with a p value < 0.05 and ∣logFC ∣ ≥1 were selected as differentially expressed. TheDEmiRNAs with log FC ≥ 1 was defined as upregulatedDEmiRNAs, while the DEmiRNAs with log FC ≤ −1 weredefined as downregulated DEmiRNAs. The overlappingDEmiRNAs expressed in the osteogenic differentiation ofDPSC and BMSC were found by uploading the list ofDEmiRNAs in the Venn web tool webpage (http://bioinformatics.psb.ugent.be/webtools/Venn/).
2.4. Target Genes of the Overlapping DEmiRNAs in DPSC andBMSC Osteodifferentiation. After identifying the overlappedDEmiRNAs that were dysregulated in both DPSC and BMSCosteodifferentiation, their target genes were extracted bydownloading the human miRNA-target interaction pairsfrom three databases including miRDB Version 6.0 [28],miRWalk [29], and TargetScan v7.1 [30]. The overlappingDEmiRNA-target gene interaction network was thereforeconstructed, and the target genes with the top degree wereidentified.
2.5. Functional Enrichment Analysis of Target Genes ofDEmiRNAs. After obtaining the DEmiRNAs expressed dur-ing the osteogenic differentiation of DPSC and BMSC, targetgenes of DEmiRNAs involved in DPSC osteodifferentiation
and BMSC osteodifferentiation were, respectively, extractedby downloading the human miRNA-target interaction pairsfrom three databases mentioned earlier [28–30]. The func-tional enrichment analysis (FEA) was performed on thetarget genes of DEmiRNAs expressed in the osteogenic dif-ferentiation of DPSC and BMSC. This analysis was con-ducted by using the clusterProfiler package of the Rprogram [31]. The functions of the candidate target genesof the DEmiRNAs were explored by assessing their enrich-ment in Gene Ontology (GO) terms, in particular biologicalprocesses (BPs) and the pathway enrichment analysisaccording to the Kyoto Encyclopedia of Genes and Genomes(KEGG). The GO terms and KEGG pathways with a p value< 0.05 were considered to be significantly enriched. If thenumber of enriched BPs and pathways was greater than 30,only the top 30 with the highest p values were chosen to bevisualized in the bar plot. If the number of enriched BPsand pathways was lower than 30, all of the BPs and pathwayswere visualized in the bar plot.
2.6. Construction of DEmiRNA-Transcription Factor (TF)Interaction Network. Based on the DEmiRNAs obtained byDEA, the DEmiRNA-transcription factor (TF) interactionpairs were derived from the TransmiR database [32]. TheDEmiRNA-TF regulatory networks involved in the DPSCosteogenesis and BMSC osteogenesis were, respectively, plot-ted by using the Cytoscape software version 3.7.2. The topo-logical characteristics of the nodes in these two networkswere calculated. The top 30 TFs with the highest degree in
GSE138180miRNA expression profile in
DPSC osteodifferentiation
Functional enrichment analysis oftarget genes
DEmiRNAs-transcription factorsinteraction network
GSE107279miRNA expression profile inBMSC osteodifferentiation
DEmiRNAs dysregulated inDPSC osteodifferentiation
DEmiRNAs dysregulated inBMSC osteodifferentiation
Functional enrichment analysisof target genes
Overlapping DEmiRNAs
Overlapping biological processesand signaling pathways
Overlapping transcription factors
DEmiRNAs-small molecular druginteraction network Overlapping small molecular drugs
Overlapping processesDPSC
osteodifferentiationBMSC
osteodifferentiation
DEmiRNAs-transcription factorsinteraction network
DEmiRNAs-small molecular druginteraction network
Target genes of overlapping DEmiRNAs
Figure 1: The study flowchart.
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these two networks were selected, and their intersection wasobtained. The intersection between the top 30 TFs of thesetwo networks could be regarded as critical overlapping TFsthat targeted DEmiRNAs dysregulated in both the DPSCand BMSC osteodifferentiation.
2.7. Construction of DEmiRNA-Small Molecular Drug TargetInteraction Network. The SM2miR database provides infor-mation about experimentally validated linkage betweenmiRNAs and bioactive small molecules that can influenceexpression levels of the miRNAs [33]. This database contains2,925 relationship pairs between small molecule drugs andmiRNAs in 17 species, and only the data related to humanspecies were collected. A total of 2,756 human interactionpairs between miRNAs and small molecular drugs were col-lected from this database. The interaction pairs of (DEmiR-NAs (DPSC osteodifferentiation)-small molecule targets)and (DEmiRNAs (BMSC osteodifferentiation)-small mole-cule targets) were, respectively, extracted from databaseSM2miR v1.0 [33]. Subsequently, the DEmiRNAs-smallmolecule drug targets networks were constructed for DPSCand BMSC osteodifferentiation by the means of Cytoscapesoftware version 3.6. In these two networks, the expressionpatterns (up-/downregulation) of miRNAs were definedaccording to their expression in the DPSC and BMSCosteodifferentiation, rather than their expression patternsshown in the SM2miR database. Consequently, the inter-sections between these two networks were identified basedon the overlapping DEmiRNA-small molecule interactionpairs and the overlapping small molecules.
3. Results
3.1. Dataset Procurement. Preselection of data relevant to themiRNA expression profiling of DPSC and BMSC in thecourse of the osteogenic differentiation process brought abouttwo datasets (GSE138180 and GSE107279). The GSE138180dataset (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138180) reported the miRNA expression alteration ofDPSC investigated by comparing the 14th day of postdifferen-tiation with the 14th day of culturing cells without differentia-tion. The GSE107279 dataset (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE107279) addressed the miRNAexpression alteration of BMSC by comparing the 13th day ofpostdifferentiation with day 0 (nondifferentiated cells whileprior to differentiation).
3.2. The Overlapping DEmiRNAs during the OsteogenicDifferentiation between DPSC and BMSC. After performingDEA based on two datasets (GSE138180 and GSE107279),186 DEmiRNAs (122 upregulated and 64 downregulated)and 104 DEmiRNAs (52 upregulated and 52 downregulated)were identified as differentially expressed in the osteogenicdifferentiation processes of DPSC and BMSC, respectively(Figure 2. File S1 and S2 showed the dysregulation of allDEmiRNAs dysregulated in the osteodifferentiation ofDPSCs and BMSCs. The top 30 DEmiRNAs of GSE138180and GSE107279 were listed in Table 1, ranked in the ascend-ing order of their p value. The explanation of the abbreviated
parameters shown in Table 1 was listed as below: logFC:log2 fold change; AveExpr: average expression across allsamples; t: logFC divided by its standard error; p.value:raw p value (based on t) from the test that logFC differsfrom 0; adj.p.Val: Benjamini-Hochberg false discovery rateadjusted p value; B: log-odds that miRNA is DE; expres-sion patterns: DEmiRNA is upregulated or downregulated.
As shown in the Venn diagram (Figure 2), a total of 186DEmiRNAs (122 upregulated and 64 downregulated) and104 DEmiRNAs (52 upregulated and 52 downregulated)were identified to be involved in the osteodifferentiation ofDPSCs and BMSCs, respectively. 16 DEmiRNAs were identi-fied as relevant for the osteogenic differentiation of bothDPSCs and BMSCs. Among these 16 overlapped DEmiNAs,eight DEmiRNAs (i.e., miR-101-3p, miR-143-3p, miR-145(3p/5p), miR-19a-3p, miR-34c-5p, miR-3607-3p, miR-378e,and miR-671 (3p/5p)) were found to show the same expres-sion patterns in the osteodifferentiation course (2 weeks) ofboth DPSCs and BMSCs, while another eight DEmiRNAs(i.e., miR-1273g-3p, miR-146a-5p, miR-4508, miR-4516,miR-6087, miR-146b-5p, miR-337-3p, and miR-382-3p)were found to show the different expression patterns. Amongthe eight DEmiRNAs with the same expression patterns,seven DEmiRNAs were found to be upregulated in the oste-ogenic differentiation course (~2 weeks) of both DPSCs andBMSCs: miR-101-3p, miR-143-3p, miR-145(3p/5p), miR-19a-3p, miR-34c-5p, miR-3607-3p, and miR-378e; andanother one DEmiRNA (miR-671 (3p/5p)) was found to bedownregulated in the osteogenic differentiation course (2weeks) of both DPSCs and BMSCs. Another eight DEmiR-NAs were divergently expressed in DPSCs and BMSCsthroughout the osteogenic differentiation course (2 weeks),e.g., five miRNAs were found downregulated in DPSCs whileupregulated in BMSCs (i.e., miR-1273g-3p, miR-146a-5p,miR-4508, miR-4516, and miR-6087), as well as three miR-NAs upregulated in DPSCs while downregulated in BMSCs(i.e., miR-146b-5p, miR-337-3p, and miR-382-3p). Amongthese 16 DemiRNAs, 11 of them (i.e., miR-19a-3p, miR-3607-3p, miR-378e, miR-671 (3p/5p), miR-1273g-3p, miR-146b-5p, miR-337-3p, miR-4508, miR-4516, miR-6087, andmiR-382-3p) were not supported by previous evidence tobe involved in the osteodifferentiation of stem cells. Thefunctions of other five DEmiRNAs (i.e., miR-101-3p, miR-143-3p, miR-145 (3p/5p), miR-34c-5p, and miR-146a-5p)in the osteodifferentiaton of DPSCs and BMSCs were sum-marized in Table 2.
3.3. The Target Genes of the 16 Overlapped DEmiRNAs. Inorder to identify the target genes of the 16 overlappingDEmiRNAs, their DEmiRNA-target interaction networkwas constructed (Figure 3). The topological characteristicsof all nodes of this network were shown in File S3, and thetopological features of the top 30 gene nodes of this networkwere shown in Table 3. As shown in Table 3, genes CCND2(cyclin D2), THBS1 (thrombospondin-1), CCND1 (cyclinD1), IGF1R (insulin-like growth factor 1 receptor), REL(REL proto-oncogene, NF-KB subunit), and ELK4 (ETStranscription factor ELK4)) were identified as the targetgenes of 16 DEmiRNAs.
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3.4. The Overlapping Biological Processes and PathwaysInvolved in the Osteogenic Differentiation of DPSCs andBMSCs. Subsequently, by the means of the functional enrich-ment analysis, the significantly enriched biological processes(BPs) and signaling pathways in target genes of the DEmiR-NAs were identified for DPSCs and BMSCs (Figures 4 and 5).The overlapping BPs and pathways involved in the osteo-genic differentiation of DPSCs and BMSCs were singledout. As shown in Figure 4, several BPs were identified asoverlapping and therefore common for osteogenic differenti-ation of both DPSCs and BMSCs: p53 binding, protein het-erodimerization activity, ATPase activity, GTPase binding,cadherin binding, and histone binding DPSCs and BMSCs.As shown in Figure 5, a total of 12 signaling pathways wereidentified as overlapped between DPSCs and BMSCs: TNF,mTOR, Hippo, neutrophin, pathways regulating pluripo-tency of stem cells, cell cycle, MAPK, focal adhesion,ubiquitin-mediated proteolysis, viral carcinogenesis, autoph-agy, and protein processing in endoplasmic reticulum andendocytosis.
3.5. The Overlapping Transcription Factors Targeted byDEmiRNAs between DPSCs and BMSCs. As shown inFigure 6, the DEmiRNA-transcription factor (TF) interactionnetwork involved in both DPSCs and BMSCs were con-structed. The top 30 TFs with the highest degree in thesetwo networks were listed in Table 4 ranking in the descending
order of degree. By comparing the top 30 TFs with the highestdegree in these two networks shown in File S4 and File S5, atotal of 26 transcription factors were found overlapped, e.g.,TCF12, ERG, CEBPB, ELF1, TCF3, ARNTL, KDM2B, MYC,BRD4, CTCF, MAX, LARP7, HIF1A, E2F1, KDM5B, MAZ,PHF8, STAT1, EP300, AR, FOXA1, TFAP2C, RUNX1,ESR1, TRIM28, and SPI1.
3.6. The Overlapping Small Molecules Targeted by DEmiRNAsDysregulated in DPSCs and BMSCs Osteodifferentiation. TheDEmiRNA-small molecular drug target interaction network,respectively, involved in DPSCs and BMSCs osteodifferen-tiation were shown in Figures 7(a) and 6(b). In the SM2miRdatabase, only 40 DEmiRNAs of DPSC osteodifferentiationand 27 DEmiRNAs of BMSC osteodifferentiation werefound to be targeted and regulated by the small moleculardrugs. The small molecular drugs in this database were notfound to target and impact the expression of the otherDEmiRNAs that were also dysregulated in DPSC and BMSCosteodifferentiation. By assessing the interaction pairs shownin Figures 7(a) and 7(b), we identified 13 interaction pairsconsisting of four DEmiRNAs (hsa-miR-143-3p, hsa-miR-146b-5p, hsa-miR-34c-5p, and hsa-miR-671-5p). 13 smallmolecules were found to be shared between the two net-works that are displayed in Table 5. Additionally, a total of19 small molecule drugs were found to not only impact theexpression of DEmiRNAs in DPSC osteodifferentiation but
168 DEmiRNAs 86 DEmiRNAs16
DEmiRNAs
7 DEmiRNAsupregulated
hsa-miR-101-3phsa-miR-143-3p
hsa-miR-145 (3p/5p)hsa-miR-19a-3phsa-miR-34c-5p
hsa-miR-3607-3phsa-miR-378e
1 DEmiRNAsdownregulated hsa-miR-671 (3p/5p)
8 DEmiRNAssame expression pattern in
DPSC and BMSC osteodifferentiation
8 DEmiRNAsdifferent expression pattern in
DPSC and BMSC osteodifferentiation
DEmiRNAsStem cells DPSCs BMSCs
hsa-miR-1273g-3p down uphsa-miR-146a-5p down uphsa-miR-146b-5p up downhsa-miR-337-3p up downhsa-miR-382-3p up downhsa-miR-4508 down uphsa-miR-4516 down uphsa-miR-6087 down up
DPSCosteodifferentiation
BMSCosteodifferentiationOverlapping
UpregulatedDEmiRNAs
DownregulatedDEmiRNAs Total DEmiRNAs
GSE138180 (DPSC osteodifferentiation) 122 64 186GSE107279 (BMSC osteodifferentiation) 52 52 104
Datasets
Figure 2: 16 DEmiRNAs identified to be overlapped in the osteodifferentiation of DPSCs and BMSCs.
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Table 1: The top 30 DEmiRNAs expressed in the osteogenic differentiation of DPSCs and BMSCs, ranked in the ascending order oftheir p value.
The top 30 DEmiRNAs dysregulated in DPSC osteodifferentiation
DEmiRNAs logFC p.value Adj.p.Val Expression pattern
hsa-let-7f-2-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-1468-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-153-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-212-5p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-2355-5p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-342-5p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-3658 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-450a-1-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-450b-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-4639-5p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-4730 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-508-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-548d-5p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-588 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-6077 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-99a-3p 4.542015233 1:45E − 06 0.000106517 Up
hsa-miR-1203 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-1238-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-128-2-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-1288-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-129-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-138-1-3p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-141-3p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-1972 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-3074-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-339-5p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-33a-3p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-34b-3p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-369-3p 4.1591475 2:09E − 06 0.000106517 Up
hsa-miR-382-3p 4.1591475 2:09E − 06 0.000106517 Up
The top 30 DEmiRNAs dysregulated in BMSC osteodifferentiation
DEmiRNAs logFC p.value Adj.p.Val Expression pattern
hsa-miR-3182 -5.37979 5:96E − 105 3:54E − 102 Up
hsa-miR-182-5p 2.561101 1:58E − 69 4:67E − 67 Down
hsa-miR-335-3p 5.160868 3:61E − 59 7:13E − 57 Down
hsa-miR-4284 -5.15177 2:73E − 56 4:05E − 54 Up
hsa-miR-92b-3p 1.590835 1:49E − 45 1:76E − 43 Down
hsa-miR-21-5p -1.35202 5:02E − 44 4:96E − 42 Up
hsa-miR-101-3p -1.49927 2:63E − 43 2:23E − 41 Up
hsa-miR-181a-5p -1.3232 2:30E − 37 1:70E − 35 Up
hsa-miR-143-3p -1.96642 1:91E − 34 1:26E − 32 Up
hsa-miR-210 2.509065 8:42E − 34 4:99E − 32 Down
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also that of DEmiRNAs in BMSC osteodifferentiation: 5-fluorouracil, anthocyanin, arsenic trioxide, ascorbate, ator-vastatin, bromocriptine, curcumin, docosahexaenoic acid,ginsenoside Rh2, glucose, hesperidin, hydroxycamptothecin(HCPT), microcystin-LR (MC-LR), mistletoe lectin-I, nar-angin, proanthocyanin, progesterone, vitamin D3, and vori-nostat (SAHA). Table 6 shows the targeting relationshipbetween 19 overlapping small molecule drugs and their reg-ulated DEmiRNAs, respectively, expressed in DPSC andBMSC osteodifferentiation process.
4. Discussion
This study identifies multiple genetic and epigenetic bio-markers common for osteogenic differentiation of DPSCsand BMSCs, including miRNAs, their target genes, transcrip-tion factors, signaling pathways, and small molecular drugsaffecting those mentioned. The overlapping miRNAs withthe same expression pattern in DPSC and BMSC osteodiffer-entiation were obtained by investigating the dysregulatedDEmiRNAs in both DPSC and BMSC osteogenesis. The
Table 1: Continued.
hsa-miR-146a-5p -3.4374 1:93E − 33 1:04E − 31 Up
hsa-miR-192-5p -1.78251 2:03E − 31 1:00E − 29 Up
hsa-miR-146b-5p 2.019632 4:61E − 30 2:10E − 28 Down
hsa-miR-335-5p 4.772695 3:12E − 28 1:32E − 26 Down
hsa-miR-382-5p 2.241351 1:20E − 25 4:76E − 24 Down
hsa-miR-4485 -6.6002 4:46E − 24 1:65E − 22 Up
hsa-miR-27b-5p 1.588671 2:77E − 21 9:68E − 20 Down
hsa-miR-10b-5p -1.21399 4:59E − 20 1:51E − 18 Up
hsa-miR-4532 -6.35341 5:95E − 19 1:86E − 17 Up
hsa-miR-34c-5p -1.82262 8:35E − 18 2:36E − 16 Up
hsa-miR-181c-5p -1.15476 1:18E − 17 3:19E − 16 Up
hsa-miR-409-3p 1.1162 1:06E − 15 2:73E − 14 Down
hsa-miR-218-5p 1.374343 2:30E − 15 5:61E − 14 Down
hsa-miR-22-5p 2.004899 2:36E − 15 5:61E − 14 Down
hsa-miR-133b -6.46427 4:93E − 14 1:08E − 12 Up
hsa-miR-3195 -5.55444 5:12E − 14 1:09E − 12 Up
hsa-miR-133a -6.42493 6:09E − 14 1:24E − 12 Up
hsa-miR-6723-5p -3.89682 7:78E − 12 1:44E − 10 Up
hsa-miR-4497 -3.78672 1:67E − 11 3:00E − 10 Up
hsa-miR-4488 -7.47261 2:43E − 11 4:11E − 10 Up
Table 2: The dysregulation and function of five overlapping DEmiRNAs (miR-101-3p, miR-143-3p, miR-145 (3p/5p), miR-34c-5p, and miR-146a-5p) in the osteodifferentiation of BMSCs and DPSCs, respectively.
BMSC osteodifferentiation DPSC osteodifferentiation
miR-101-3p
The overexpression of miR-101 promoted the osteogenic differentiationof BMSCs by targeting EZH2/Wnt/β-catenin signaling [34].
No evidence.
miR-143-3p
The downregulation of miR-143 promoted the osteogenic differentiationof BMSCs by being competitively combined with lncRNAMALAT1 and
upregulating Osterix (Osx) [35].
The downregulation of miR-143 promoted theosteogenic differentiation of DPSCs by activating the
NF-κB [36] and OPG/RANKL signaling [37].
miR-145(3p/5p)
The downregulation of miR-145 promoted the osteogenic differentiationof BMSCs by targeting semaphorin3A (SEMA3A) [38].
The downregulation of miR-145 promoted theodontoblast differentiation of DPSCs by targeting
KLF4 and OSX [39].
miR-34c-5p
The upregulation of miR-34c inhibited osteoblast differentiation ofBMSCs by targeting the Notch signaling [40].
No evidence.
miR-146a-5p
The overexpression of miR-146a inhibited the osteogenic ability ofBMSCs by targeting Smad4 gene [41].
The overexpression of miR-146a-5p promotedosteodifferentiation of DPSCs by suppressing Notch
signaling [42].
7BioMed Research International
target genes of those shared DEmiRNAs were identified byconstructing the shared DEmiRNA-target gene network.The TFs among those genes, signaling pathways involved,and small molecule drugs that predictively affect those path-ways were identified as highly plausible common regulatorsof the osteodifferentiation process in both DPSCs andBMSCs. Their involvement in DPSC and BMSC osteodiffer-entiation will be discussed here.
This discussion addresses several of the eight miRNAsthat were found to be differentially expressed, with the sameexpression pattern in the course of osteogenic differentiationof DPSCs and BMSCs (miR-101-3p, miR-143-3p, miR-145(-3p/-5p), miR-19a-3p, miR-34c-5p, miR-3607-3p, miR-378e, and miR-671 (-3p/-5p)). Since there has not been anyevidence showing the involvement of miR-19a, miR-3607,miR-378e, and miR-671 in osteogenesis of stem cells, weexcluded them from further discussion in order to avoidspeculation. The possible role of the other four miRNAs(miR-101, miR-143, miR-145, and miR-34 family (miR-34a/b/c)) will be interpreted in the following part of this sec-tion. Overexpression of miR-101 was shown to targetEZH2/Wnt/β-Catenin signaling, hereby promoting the oste-ogenic differentiation in general [34]. Nevertheless, no evi-dence has been produced to corroborate the expressionpattern and either promoting or an inhibiting role of miR-101 during the osteogenesis of DPSCs. The miR-143 has been
designated with an evident inhibiting role in osteogenesisand odontogenesis. Downregulation of miR-143 has beenshown to promote the osteogenic and odontogenic differen-tiation of DPSCs by activating the NF-κB [36] andOPG/RANKL signaling [37]. The decreased expression ofmiR-143 was also shown to promote the osteogenic differen-tiation of BMSCs by being competitively combined withlncRNA MALAT1 and further upregulating the expressionof Osterix (Osx), suggesting that MALAT1-miR-143-Osxcould be an integrative element in the ceRNA network ofBMSC osteogenesis [35]. Opposite to the results shown inthese previous studies, the present study shows an upregula-tion of miR-143 during the osteogenic differentiation in bothBMSCs and DPSCs. miR-145 (-3p/-5p) appears to functionthe same way as miR-143. The downregulation of miR-145can apparently promote the odontoblast differentiation ofDPSC by targeting transcriptional factor KLF4 and OSX[39]. Also, the downregulation of miR-145 can promote oste-ogenic differentiation of BMSC by targeting semaphorin3A(SEMA3A), a known positive regulator of osteogenesis [38].Similarly to the miR-143, the expression pattern of miR-145 shown in the previous work of others is not in agreementwith the in silico data derived from the datasets analyzed inthis study, which show that miR-145 is overexpressed inthe course of osteodifferentiation of both DPSCs and BMSCs.The miR-34 family (miR-34a/b/c) has so far not been
hsa-miR-671-3p
hsa-miR-6087
hsa-miR-4516
GIGYF1
MDM2
BTG2
hsa-miR-4508hsa-miR-382-3p
hsa-miR-378e
hsa-miR-143-3p
hsa-miR-3607-3p
hsa-miR-34c-3p
hsa-miR-337-3p
hsa-miR-101-3phsa-miR-19a-3p
hsa-miR-146b-5p
hsa-miR-146a-5p
hsa-miR-145-5p
hsa-miR-145-3p
hsa-miR-671-5p
CCND1
CCND2
IGF1R
IREB2
NUFIP2
REL
THBS1
TNRC6A
UBN2
UHMK1
EIF4G2 ELK4ETNK1
HNRNPU
HNRNPUL1
LRRC58
MAP1B
NACC1
PANK3
PRDM2
PURB
REV3LRREB1SFT2D2TET3
TMBIM6
TNPO1
ZNF264
ZNF678
ALDOA
CCDC80
NF2
CBX6
DDX21
ADAM10CDKN1A
Figure 3: The overlapping 16 DEmiRNA-target gene network. The top 30 target genes with the highest degree were displayed enlarged in thenetwork.
8 BioMed Research International
designated as categorically pro- or counterosteogenic inDPSCs. Two surveys have shown the involvement of themiR-34 family in the osteogenic differentiation of BMSC[43, 44], however, with quite contradictory results about itsexpression pattern. Chen et al. showed that miR-34a couldinhibit osteogenesis by suppressing regulators cell cycle andcell proliferation cyclin D1, CDK4, and CDK6 [43] and thatthe inhibition of miR-34a could facilitate osteogenesis of
BMSCs. Contrary to that, Xin et al. showed that the upregu-lation of miR-34a could promote osteogenesis of BMSCs andreverse proinflammatory cytokine influence by targetingtumor necrosis factor-alpha (TNF-α) [45]. Altogether, theosteogenesis-relevant DEmiRNAs that were found overlap-ping in DPSCs and BMSCs are involved in signaling path-ways that regulate differentiation and inflammatoryprocesses by targeting their major regulators.
Table 3: The topological characteristics of the top 30 target genes with the highest degree in the 16 overlapping DEmiRNA-target genenetwork. Typically, this table would be displaying only the top 30 target genes with the highest degree; since 26 target genes were rankedwith the degree of 6, a total of 39 target genes with a degree ≥ 6 were finally listed in this table.
Name Degree Average shortest path length Betweenness centrality Closeness centrality Topological coefficient
BTG2 8 2.431705 0.003363 0.411234 0.18598065
CCND2 8 2.517604 0.003716 0.397203 0.16845654
NUFIP2 8 2.449032 0.003768 0.408325 0.18394988
THBS1 8 2.231521 0.005344 0.448125 0.17855649
UBN2 8 2.587281 0.004042 0.386506 0.17526212
GIGYF1 8 2.589493 0.003609 0.386176 0.17635862
CCND1 7 2.485899 0.002815 0.402269 0.19450361
IGF1R 7 2.426175 0.003724 0.412171 0.19710456
IREB2 7 2.631152 0.00312 0.380062 0.20047142
REL 7 2.838341 0.002574 0.352318 0.19393939
TNRC6A 7 2.514286 0.002822 0.397727 0.20702541
UHMK1 7 2.499171 0.002866 0.400133 0.20764488
MDM2 7 2.519816 0.003737 0.396854 0.19915693
ADAM10 6 2.52682 0.001899 0.395754 0.24168969
CDKN1A 6 2.667281 0.001979 0.374914 0.2337037
EIF4G2 6 2.655853 0.001796 0.376527 0.23616084
ELK4 6 2.542304 0.001911 0.393344 0.24100872
ETNK1 6 2.726636 0.001859 0.366752 0.23112339
HNRNPU 6 2.652903 0.001945 0.376946 0.23472566
HNRNPUL1 6 2.610876 0.001817 0.383013 0.23927525
LRRC58 6 2.652903 0.001945 0.376946 0.23472566
MAP1B 6 2.741382 0.001822 0.364779 0.21069923
NACC1 6 2.780092 0.002673 0.3597 0.22723133
PANK3 6 2.901382 0.002215 0.344663 0.20067454
PRDM2 6 2.437235 0.002245 0.410301 0.22983744
PURB 6 2.785622 0.002027 0.358986 0.2084477
REV3L 6 2.652166 0.001623 0.37705 0.23674815
RREB1 6 2.823594 0.002115 0.354159 0.20654912
SFT2D2 6 2.652166 0.001623 0.37705 0.23674815
TET3 6 2.52682 0.001899 0.395754 0.24168969
TMBIM6 6 2.52682 0.001899 0.395754 0.24168969
TNPO1 6 2.567373 0.002674 0.389503 0.23314389
ZNF264 6 2.627834 0.001775 0.380542 0.23815304
ZNF678 6 2.57106 0.001949 0.388945 0.23931624
ALDOA 6 2.781198 0.002859 0.359557 0.21913299
CCDC80 6 2.662488 0.00286 0.375588 0.20698404
NF2 6 3.205161 0.002464 0.311997 0.2200685
CBX6 6 2.693456 0.001811 0.37127 0.2316048
DDX21 6 2.772719 0.001683 0.360657 0.22691611
9BioMed Research International
Transcription coregulator activityUbiquitin−like protein ligase binding
Ubiquitin protein ligase bindingCadherin binding
Ubiquitin−like protein transferase activityUbiquitin−protein transferase activity
GTPase bindingCell adhesion molecule binding
Transcription coactivator activityProtein serine/threonine kinase activity
Chromatin bindingProximal promoter sequence−specific DNA binding
Transcription corepressor activityAmall GTPase binding
Ras GTPase bindingProtein C−terminus binding
Helicase activityProtein heterodimerization activity
ATPase activity, coupledProtein N−terminus binding
ATPase activityUbiquitin−like protein ligase activity
Ubiquitin protein ligase activityHistone binding
DNA−dependent ATPase activityGDP binding
Ribonucleoprotein complex bindingNuclear hormone receptor binding
Phosphatidylinositol bindingp53 binding
0.0e+00 5.0e−08 1.0e−07 1.5e−07
Biol
ogic
al p
roce
ss
Count100
200
10
15
20
25
−1⁎log10 (p value)
300
400
p value
(a)
Figure 4: Continued.
10 BioMed Research International
After identifying 16 overlapping DEmiRNAs, the targetgenes of these 16 DEmiRNAs were also identified by con-structing the corresponding DEmiRNA-target gene net-work. Among the top 30 target genes of 16 overlappingDEmiRNAs, only some typical examples of genes will bediscussed based on the previous literature evidence regard-ing their involvement in the osteodifferentiation of DPSCsand BMSCs (e.g., REL, CCND1/2, IGF1R, THBS1, andELK4). REL gene family consists of RelA (p65), RelB, andc-Rel, subunits of NF-KB. Activation of NF-KB subunitRelA (p65) was shown to significantly promote inflamma-tion and inhibit osteodifferentiation of BMSCs by promot-ing the ubiquitination and degradation of beta-catenin,indicating that inhibitors of RelA (p65) could be a novel
therapeutic target for inhibiting inflammation and enhanc-ing osteogenesis [46]. In accordance with the findingsshown in BMSCs, studies investigating DPSCs also showedthat the downregulation of NF-KB subunit RelA (p65)enhanced the odontogenic/osteogenic differentiation ofDPSCs [47, 48]. Cyclin D genes are involved in cell cycleregulation. Silencing of cyclin D genes (CCND1/2) wasshown to arrest the cell cycle, and its overexpression hasbeen connected to the progression of the cell cycle [49].That the data regarding the effects of cell cycle regulatorson osteodifferentiation have so far been insufficiently coher-ent, CCND1/2 expression was significantly upregulated inthe course of DPSC osteodifferentiation [50, 51], whereasduring BMSC differentiation the genes involved in the cell
Cadherin bindingCell adhesion molecule binding
Ubiquitin−like protein ligase bindingUbiquitin protein ligase binding
Transcription coregulator activityChromatin binding
RNA polymerase II proximal promoter sequence−specific DNA bindingProximal promoter sequence−specific DNA binding
GTPase bindingTranscription coactivator activity
Small GTPase bindingUbiquitin−like protein transferase activity
Ras GTPase bindingUbiquitin−protein transferase activity
Protein serine/threonine kinase activityProtein C−terminus binding
ATPase activity, coupledTranscription corepressor activity
ATPase activityRibonucleoprotein complex binding
Histone bindingActin binding
Protein heterodimerization activityTranslation factor activity, RNA binding
p53 bindingPhosphatase binding
Helicase activityNuclear hormone receptor binding
Enhancer sequence−specific DNA bindingPhosphoric ester hydrolase activity
Biol
ogic
al p
roce
ss
0e+00 1e−07 2e−07 3e−07 4e−07p value
−1⁎log10 (p value)
Count100
200
300
400
10
15
20
(b)
Figure 4: The enriched biological processes involved in the osteogenic differentiation of DPSC (a) and BMSC (b).
11BioMed Research International
Proteoglycans in cancer
Endocytosis
Protein processing in endoplasmic reticulum
Chronic myeloid leukemia
EGFR tyrosine kinase inhibitor resistance
Human papillomavirus infection
Viral carcinogenesis
Ubiquitin mediated proteolysis
Focal adhesion
Hippo signaling pathway
Hepatocellular carcinoma
Colorectal cancer
Yersinia infection
Signaling pathways regulating pluripotency of stem cells
Neurotrophin signaling pathway
Pancreatic cancer
Renal cell carcinoma
MAPK signaling pathway
Breast cancer
Spliceosome
Herpes simplex virus 1 infection
Cell cycle
Prostate cancer
ErbB signaling pathway
mTOR signaling pathway
Axon guidance
TNF signaling pathway
Shigellosis
FoxO signaling pathway
Path
way
0.0e+00 5.0e−09 1.0e−08 1.5e−08
8
10
12
14
−1 ⁎log10 (p value)
Count100200300
p value
Autophagy – animal
(a)
Figure 5: Continued.
12 BioMed Research International
cycle were significantly downregulated [52]. IGF1R (insu-lin-like growth factor 1 receptor) can bind IGF1 with a highaffinity [53]. The previous studies regarding BMSCs alsoshowed that IGF1 promoted osteodifferentiation of BMSCsand could even be regarded as an alternative biomarker tobone morphogenetic protein-7 [54, 55]. In addition, theIGF axis (e.g., IGF-2 and IGFBP-2) was activated underosteogenic conditions in DPSCs, indicating its promotingrole in DPSC osteodifferentiation [56]. THBS1 (thrombos-pondin-1) is a major regulator of latent TGF-β activation[57], which can inhibit osteoblast differentiation in BMSCs.Accordingly, THBS1 was found to inhibit the osteodifferen-
tiation of BMSCs by activating the TGF-β pathway [58].An analogue involvement of THBS1 in osteodifferentiationof DPSCs has not been reported yet. Another modulator ofosteogenic differentiation ELK4 (ETS transcription factorELK4) was also predicted to be among the target genes of16 DEmiRNAs. Ets trasnscription factor consisting of Ets1and Ets2 targets several osteogenic markers (e.g., osteocal-cin, osteopontin, bone sialoprotein, and osteonectin) inBMSCs [59]. However, the evidence regarding the regula-tion of Ets transcription factor in the osteodifferentiationof DPSC is still lacking and thus could be a novel topicfor future research.
Proteoglycans in cancerMAPK signaling pathway
Herpes simplex virus 1 infectionHuman papillomavirus infection
Cellular senescencemTOR signaling pathway
Protein processing in endoplasmic reticulumBreast cancer
Ubiquitin mediated proteolysisRNA transport
Focal adhesionCell cycle
Hippo signaling pathwayChronic myeloid leukemia
Pancreatic cancerSignaling pathways regulating pluripotency of stem cells
EndocytosisColorectal cancer
Human T−cell leukemia virus 1 infectionp53 signaling pathway
Non−small cell lung cancerProstate cancer
Viral carcinogenesisRegulation of actin cytoskeleton
Neurotrophin signaling pathwayGastric cancer
TNF signaling pathwayHepatocellular carcinomaAMPK signaling pathway
Path
way
0e+00 2e−07 4e−07 6e−07 8e−07p value
8
10
12
−1 ⁎ log10 (p value)
Count100
200
300
Autophagy – animal
(b)
Figure 5: The enriched signaling pathway involved in the osteogenic differentiation of DPSC (a) and BMSC (b).
13BioMed Research International
hsa-miR-5703hsa-miR-1471 hsa-miR-4487
hsa-miR-4429
hsa-miR-4530
hsa-miR-3610
hsa-miR-630
hsa-miR-5684
hsa-miR-520b
hsa-miR-6088
hsa-miR-3197
hsa-miR-4267
hsa-miR-4767
hsa-miR-4522
hsa-miR-4259hsa-miR-4253
hsa-miR-6076
hsa-miR-9500
hsa-miR-4519
hsa-miR-8063
hsa-miR-4516
hsa-miR-662
hsa-miR-4642
hsa-miR-5787
hsa-miR-6321
hsa-miR-4508
hsa-miR-3164
hsa-miR-3193hsa-miR-3658
hsa-miR-640
hsa-miR-588
hsa-miR-378e
hsa-miR-4730
hsa-miR-378i
hsa-miR-6077
hsa-miR-4436a
hsa-miR-4421
hsa-miR-4293
hsa-miR-6134
hsa-miR-4282
hsa-miR-1203
CTCFLSTAT3
BRD4
SPI1
SUMO2
ERG
CHD8 JUND
CREB1
MXI1
SUPT5H LARP7
ETS1GABPA
SMC1A
NOTCH1
ZBTB7A
NR3C1
KLF1
RUNX3
CNOT3
KDM5BGATA3
MAX
SP1
ESR1
CEBPB
TFAP2A
MYCN
TAF1
PHF8TAL1
TCF3
MYC
MAZ
E2F6
FOXA1GATA1
TFAP2CTRIM28
MED1
H1F1A
RUNX1
RAD21CTCF
TCF12
KDM2B
HEY1
ELF1
AR
STAT1
EGR1
ARNTL EP300
E2F1ZNF143
MYB
YY1
DEmiRNA_up
DEmiRNA_down
TF
(a)
Figure 6: Continued.
14 BioMed Research International
Among the 13 transcription factors found to be over-lapped between the top nodes of the DPSC and BMSC oste-ogenesis DEmiRNA-TF network, four TFs (RUNX1,FOXA1, HIF1A, and MYC) have been reported relevant forosteodifferentiation of stem cells. Upregulation of Runt-related transcription factor 1 (RUNX1) was shown to pro-mote osteogenesis of BMSCs by activating the canonicalWnt/β-catenin pathway [60]. RUNX1 involvement in DPSCosteogenesis has not been shown; nevertheless, anothermember of the RUNX family (RUNX2) could enhance bonedeposition and facilitate novel bone formation after trans-plantation of RUNX2-transfected DPSCs [61]. Forkheadbox protein A1/2 (FOXA1/2) has been reported as hyper-methylated in the course of BMSC osteogenesis [62] and itsknockdown promoted BMSC osteodifferentiation [63],which has still not been reported in DPSCs. Hypoxic condi-tions are known to promote cell proliferation and enhancethe osteogenic differentiation of both BMSC and DPSC byinducing the expression of HIF1A (hypoxia-inducible factor1-alpha) and upregulating the osteogenic-related genes(e.g., Oct-4, Sox2, c-Myc, RUNX2, and PPARγ2) [64–66].HIF1A overexpression in BMSC can induce the overexpres-sion of proosteogenic genes and enhance the ALP activityeven in normoxic conditions [67]. However, there is still nodirect evidence on the regulating role of HIF1A in the osteo-differentiation process of DPSC. Overexpressed c-MYC wasmainly shown to inhibit osteogenic differentiation of bothBMSC [68] and DPSC [69]. In DPSCs, stably expressed c-MYC inhibited cell growth during osteogenic differentiationand also impaired the osteogenic phenotypes (i.e., ALP activ-ity and expression of osteogenic marker genes) [69]. On the
other hand, a microarray study of gene expression in BMSCsindicated that c-MYC mediated an upregulation of dexa-methasone (DEX) expression and of the bone morphogeneticprotein 2- (BMP2-) induced osteoblast differentiation [70].Involvement of other overlapping TFs (e.g., CTCF, BRD4,MAX, ERG, KDM5B, MAZ, EP300, AR, and ESR1) in theosteogenic differentiation of BMSC and DPSC has not beenreported yet; thus, these TFs could present novel investigat-ing markers for future research.
A total of 12 overlapping signaling pathways were foundto be enriched by the target genes of DEmiRNAs that areinvolved in the DPSC osteogenesis and BMSC osteogenesis.Among these 12 signaling pathways, five were selected ashighly relevant (i.e., TNF, mTOR, Hippo, neutrophin, andsignaling pathways regulating pluripotency of stem cells), asthe most thoroughly researched and recognized as classicpathways in the osteogenesis of stem cells. Tumor necrosisfactor (TNF) signaling cascade has been shown to affect oste-ogenic differentiation in DPSCs in a dose-dependent man-ner: proosteogenic at lower doses via activating NF-κBsignaling pathway [71] and osteosuppressing at higher dosesby modulating the Wnt/β-catenin signaling [72]. In BMSCs,the osteosuppressing effect of TNF-α is exerted through thedownregulation of miR-34a and miR-21 expression [73],which are listed among the top 30 dysregulated DEmiRNAsin osteodifferentiation of BMSCs. The mTOR signaling path-way is activated by stimulation with dexamethasone andkaempferol in DPSCs and BMSCs, respectively, suggestingmTOR as a common pathway in the course of their osteogen-esis [74, 75]. Hippo signaling pathway promotes osteogenicdifferentiation in DPSCs upon regulation by SOX2 and the
hsa-miR-3178
TAF7
NFKB1
hsa-miR-3196
hsa-miR-378e
hsa-miR-4508hsa-miR-3609
hsa-miR-133a hsa-miR-421 hsa-miR-4516 hsa-miR-4492 hsa-miR-3195hsa-miR-3141
hsa-miR-3182
hsa-miR-184
hsa-miR-4488
hsa-miR-1248
ETS1
hsa-miR-4791
hsa-miR-4497
NIPBLSP2
SRF JUND
MYOG FOXO1
TNFSF12hsa-miR-133b
CTCF
PHF8
KLF4hsa-miR-134hsa-miR-1246
hsa-miR-1468
hsa-miR-543hsa-miR-487a
calcineurin
ERGCNOT3 RING1
TCF3PIAS1
CHD8
KDM4A
GATA1
ESR1
ZNF384
TRIM24CDK9
CHD2
RAD21
SIN3ARBBP5
ZBTB7A
HAND2HOXB13
STAG1KAT7
KDM4C IRF4
TAF3OTX2NELFA
TRIM25
ATF2KLF6
NR2F1
EOMES
RELA
KDM1A
E2F1
TBP
CEBPD
GATAD1
MYCN
BRD3 POU5F1
TET2TP73
CTCFLCEBPA
MAX
GTF2F1GABPA
MYH11
CSNK2A1NR2F2
TP63MAZ
BRPF3ESR2
ZMIZ1
GATA2KMT2A
FOXA1GTF2IMAFF
TP53
HNF4AREST
GATA3CREB1
ARCEBPB
E2F4
STAT3MAFK
MYOD1TEAD4
WDR5ELF1
BCORCDK8DNMT3A
HNF4GFOSL2 EBF1
LARP7TFAP2AJUN
SIX5SFPQ
CDK7NFATC1
BRD1
TLE3
CCND2
CBFB
FOXP1
HDAC1
PRDM1BCL3
RARAVDR FOXM1
KDM2B NR1H3EGR1
CXXC1
PBX1ZBTB33HOXA4
INTS11ING5 ELL2 NRF1
INTS3E2F3SREBF2ASCL1
CHD1
MYBL2
SP1 NFE2L2
CCNT2
ASXL1ZEB1
ING2SOX9
hsa-mir-4284
NFYA HEY1
ETV1SMARCB1
KMT2D
PRDM11UBTF
BACH2ZBTB17
AHR
AFF4ZNF750
DNMT1 SPI1
MBD3
STAT1
MXI1
E2F6MED1
LMO2
XBP1
LEO1
PML
ELK1MECP2MYC
PAX5
MED26
STAT5A
TCF12
BCL6
BRF1
USF1
BATF
NOTCH1GATA4KDM5B
JMJD6
HOXA6BPTF
SMAD4
PGRSUMO1
SUMO2SMAD1
SMC1APBX3
ZNF263ZNF143
MYB
FLI1SNAI2
EZH2SMC3
DAXXTFAP2C
RUNX2TCF4CREBBP
FOSL1
SUPT5HHSF1ELF3
hsa-mir-370
hsa-miR-4521hsa-miR-4323hsa-miR-326
hsa-miR-665
hsa-mir-4485NFIC
FOXA2RUNX1
NFE2FOS
YAP1PAF1ICE1
SETD1A
EP300
RBPJ
RUNX3
EPAS1
MITF NANOG
GTF2BBCLAF1
BHLHE40
NCOR1SMAD3 USF3
LYL1SUZ12
TFAP4
KLF5HDAC2NCOA1
NR1H2
MEF2A
KLF11GRHL2
hsa-miR-210
hsa-miR-1180
IRF1JARID2
ARNTTHAP1
ZMYND8 BRD2SREBF1 YY1
TBL1XR1
NR3C1HIF1A
TAL1
TAF1NELFE
KLF1PPARG
CBX3 HCFC1
POU2F2IKZF1
GATA6HMGN3
ZNF83
RFX5PRDM5
LMNA
HIRA
WWTR1 STAR5B
RBL1 CUX1KDM3BSIX2
BRCA1JUNBRCOR1RUNX1T1
SOX2
ARNTL
NFYB FGFR1
TRIM28ATF3TCF7L2
DEmiRNA_upDEmiRNA_downTF
(b)
Figure 6: The DEmiRNA-TF interaction network involved in the osteogenic differentiation of DPSC (a) and BMSC (b).
15BioMed Research International
Table 4: DEmiRNA-transcription factor (TF) interaction network involved in DPSC and BMSC osteodifferentiation. The top 30 TFs with thehighest degree of difference in the DEmiRNA-TF network of DPSCS and BMSCS osteodifferentiation were, respectively, ranked in thedescending order of degree.
The top 30 TFs with the highest degree in DEmiRNAs-TF network of DPSC osteodifferentiationName Degree Average shortest path length Betweenness centrality Closeness centrality Topological coefficient
FOXA1 30 1.954545 0.015768 0.511628 0.223996
BRD4 29 2.008021 0.009367 0.498003 0.244796
AR 29 2.029412 0.012695 0.492754 0.226894
MAX 29 1.997326 0.009458 0.500669 0.245836
EP300 28 1.981283 0.010644 0.504723 0.248155
ESR1 27 2.024064 0.01016 0.494055 0.226708
HIF1A 27 1.986631 0.01079 0.503365 0.245075
ERG 26 2.008021 0.008387 0.498003 0.265101
KDM5B 26 1.986631 0.008951 0.503365 0.259557
CTCF 25 2.034759 0.009876 0.491459 0.25205
MYC 25 2.013369 0.008083 0.49668 0.27092
RUNX1 24 2.034759 0.006933 0.491459 0.277477
SPI1 23 2.072193 0.00707 0.482581 0.250994
ZNF143 22 2.066845 0.00628 0.483829 0.255913
MAZ 22 2.050802 0.006421 0.487614 0.279362
ELF1 22 2.05615 0.005904 0.486346 0.298782
ARNTL 22 2.109626 0.005538 0.474018 0.27185
SP1 22 2.061497 0.007389 0.485084 0.278977
TCF3 21 2.088235 0.005238 0.478873 0.281495
PHF8 21 2.136364 0.004093 0.468085 0.295021
CEBPB 21 2.125668 0.006218 0.47044 0.272461
TCF12 21 2.114973 0.005147 0.472819 0.289542
TFAP2C 21 2.136364 0.006262 0.468085 0.266791
E2F1 20 2.040107 0.006168 0.49017 0.295552
TAF1 20 2.141711 0.004164 0.466916 0.29772
CTCFL 20 2.131016 0.004453 0.46926 0.301133
MED1 19 2.195187 0.003279 0.455542 0.301484
JUND 19 2.18984 0.005712 0.456654 0.264742
NOTCH1 19 2.088235 0.004576 0.478873 0.309831
KDM2B 19 2.147059 0.003495 0.465753 0.310989
LARP7 19 2.104278 0.004425 0.475222 0.316458
STAT1 19 2.125668 0.004486 0.47044 0.303774
E2F6 19 2.088235 0.00484 0.478873 0.274578
GATA3 19 2.163102 0.004673 0.462299 0.286357
TRIM28 19 2.147059 0.004839 0.465753 0.297788
The top 30 TFs with the highest degree in DEmiRNA-TF network of BMSC osteodifferentiation
Name Degree Average shortest path length Betweenness centrality Closeness centrality Topological coefficient
MAX 20 2.021505 0.003652 0.494681 0.161047
AR 20 2.010753 0.010422 0.497326 0.149037
MYC 18 2.032258 0.002722 0.492063 0.175405
ESR1 18 2.02509 0.004109 0.493805 0.154739
MAZ 17 2.050179 0.003885 0.487762 0.163923
FOXA1 17 2.057348 0.004905 0.486063 0.139836
ERG 17 2.039427 0.002605 0.490334 0.182422
HIF1A 16 2.035842 0.00274 0.491197 0.186531
CREB1 16 2.046595 0.003777 0.488616 0.172636
16 BioMed Research International
downstream BMP signaling [76]. In murine BMSCs, theactivation of this pathway was induced by calcitoningene-related peptide (CGRP) and it promoted osteogenicdifferentiation. Neurotrophin-mediated signaling pathwaywith rain-derived neurotrophic factor (BDNF) as a keymediator is primarily active in neurogenesis [77] but alsointensively involved in osteogenesis of both DPSCs andBMSCs. In DPSCs, the upregulation of BDNF was shownto promote the odontogenic differentiation of DPSCstowards odontoblast-like cells [78] and to indirectly pro-mote osteogenesis in BMSCs [79]. In addition, a plethoraof signaling pathways that regulate the pluripotency of stemcells provides the basic framework for any differentiation,including the endpoint bone. Among several key mediators,transforming growth factor-beta (TGF-β) signaling is ofparticular importance, being implicated in regulatory path-ways relevant for osteodifferentiation as well. The activationof the TGF-β pathway promotes osteogenesis in DPSCs byupregulating osteoblast marker genes type I collagen, alka-line phosphatase (ALP), osteocalcin (OCN), and RUNX2[80], whereas in BMSCs, its function regarding osteogenesishas been reported in controversial contexts [81, 82].
Apart from the genetic and epigenetic biomarkers, thisresearch also identified 19 small molecular drugs with asimultaneous predictive impact on the DEmiRNAs that aredysregulated in both DPSC and BMSC osteodifferentiation.This section will focus on several of those small moleculesthat exhibit clear anti-inflammatory or proosteogenic effectin BMSCs: curcumin, docosahexaenoic acid (DHA), vitaminD3, arsenic trioxide, 5-fluorouracil (5-FU), and naringin.Curcumin, a natural phenolic biphenyl compound derivedfrom the plant Curcuma longa, is an antioxidant with anti-inflammatory and osteogenesis-regulating effects [83, 84].In BMSCs, curcumin facilitates differentiation towards oste-oblasts by activating Akt/GSK3β and Wnt/β-catenin path-ways [85]. Docosahexaenoic acid (DHA) belongs to theomega-3 polyunsaturated fatty acids, and it is well-knownfor being protective against inflammation. DHA promotesthe osteodifferentiation of BMSCs by leading to the upregula-tion of proosteogenic proteins bone-sialoprotein 2 (BSP2),ALP, and RUNX2 [86]. The 1α,25-dihydroxyvitamin D3, anactive metabolite of vitamin D, is crucial for the maintenanceof calcium homeostasis and balance of bone remodeling. Itinduces differentiation of human BMSCs and dental bud
Table 4: Continued.
The top 30 TFs with the highest degree in DEmiRNAs-TF network of DPSC osteodifferentiationName Degree Average shortest path length Betweenness centrality Closeness centrality Topological coefficient
EP300 15 2.050179 0.00182 0.487762 0.20078
CTCF 15 2.043011 0.002819 0.489474 0.177864
FLI1 14 2.057348 0.001999 0.486063 0.19308
BRD4 14 2.050179 0.001697 0.487762 0.205114
TP53 13 2.064516 0.002431 0.484375 0.200512
TFAP2C 13 2.071685 0.002276 0.482699 0.183618
TCF12 13 2.060932 0.001517 0.485217 0.214543
RUNX1 13 2.071685 0.001542 0.482699 0.210065
RAD21 13 2.0681 0.002309 0.483536 0.174057
KDM5B 13 2.057348 0.001707 0.486063 0.211276
CEBPB 13 2.071685 0.003446 0.482699 0.156718
TRIM28 12 2.0681 0.001403 0.483536 0.222766
TEAD4 12 2.064516 0.001834 0.484375 0.212077
STAT1 12 2.0681 0.001237 0.483536 0.229126
SPI1 12 2.075269 0.004133 0.481865 0.206451
PHF8 12 2.071685 0.001465 0.482699 0.222712
E2F1 12 2.0681 0.001526 0.483536 0.215917
TCF3 11 2.082437 0.001244 0.480207 0.225841
REST 11 2.057348 0.00601 0.486063 0.207061
NFE2 11 2.071685 0.00123 0.482699 0.231276
MYCN 11 2.071685 0.001787 0.482699 0.231098
LARP7 11 2.082437 0.001129 0.480207 0.235147
KDM2B 11 2.075269 0.00107 0.481865 0.23975
HEY1 11 2.078853 0.001289 0.481034 0.231113
ELF1 11 2.089606 0.001158 0.478559 0.227812
EBF1 11 2.075269 0.001284 0.481865 0.220856
ARNTL 11 2.082437 0.001177 0.480207 0.22781
17BioMed Research International
stem cells (DBSCs) towards osteoblasts by increasing theexpression levels of osteogenic markers (RUNX2, collagenI (Coll I), ALP, osteopontin, and osteocalcin) [87, 88]. Arse-nic trioxide (ATO) is a drug which has been commonlyused in treating acute promyeloid leukemia (APL) [89].Additionally, ATO was shown to promote the osteogenicdifferentiation of BMSC while inhibiting their adipogenic
differentiation [90, 91]. The 5-fluorouracil (5-FU) is a com-monly used drug in cancer treatment based on inducing thecell death of cycling cells [92]. BMSCs treated with 5-FUexhibited an enhanced osteodifferentiation [93]. Naringin isa dihydrotestosterone flavonoid compound known to pro-mote osteodifferentiation of BMSCs by downregulatingexpression levels of peroxisome proliferator-activated
hsa-miR-630
hsa-miR-450b-3p
GinsenosideRh2
Dihydrotestosterone (DHT)
hsa-miR-483-3p
Microcystin-LR(MC-LR)
Hesperidin
Formaldehyde
hsa-miR-188-5p
hsa-miR-17-3p
hsa-miR-135a-3p
Ascorbatehsa-miR-10a-5p
Narangin
hsa-miR-1972Hydroxycamptothecin
(HCPT)
hsa-miR-181a-2-3p
hsa-miR-224-3p
hsa-miR-671-5p
Proanthocyaninhsa-miR-423-5p
hsa-miR-574-3p
Ferulicacid
Vorinostat(SAHA)
17beta-estradiol(E2)
Medroxyprogesteroneacetate
hsa-miR-542-3p Ethanol
hsa-miR-450a-5p
Anthocyanin
Curcumin
hsa-miR-378i
hsa-miR-339-5p
Bromocriptine
hsa-miR-3658
5-Fluorouracil
hsa-miR-140-3p
hsa-miR-193b-3p
hsa-miR-143-3p
Docosahexaenoicacid
VitaminD3
hsa-miR-191-5p
hsa-miR-141-3p
hsa-miR-342-3p
Glucocorticoid
hsa-miR-4639-5p hsa-miR-4668-5phsa-miR-4767
Floxuridine(FdU)
hsa-miR-455-3p
FdUMP[10]
Cisplatin
hsa-miR-224-5phsa-miR-548d-5p
hsa-miR-525-5p
Atorvastatin
hsa-miR-146b-5p Progesterone
Arsenictrioxide
hsa-miR-34c-5p
Glucose
hsa-miR-129-5p
hsa-miR-508-3p
hsa-miR-342-5p Mistletoelectin-I
hsa-miR-491-3p
hsa-miR-369-3p
hsa-miR-520b
hsa-miR-199b-5p
Imatinibmesylate
TrichostatinA
(TSA)
DEmiRNA_upDEmiRNA_down
Small_molecule
(a)
hsa-miR-1283
hsa-miR-143-3p
Docosahexaenoicacid
hsa-miR-181a-5p
hsa-miR-3195Oleicacid
GinsenosideRh2
hsa-miR-3656
hsa-miR-487ahsa-miR-146b-5phsa-miR-370
hsa-miR-4284
Berbaminederivative (BBMD3)
hsa-miR-335-5p hsa-miR-34c-5p
Anthocyaninhsa-miR-331-3p
Curcumin
Trastuzumab
Vincristine
Bicalutamide
Lenalidomide
5-aza-2′-deoxycytidine(5-Aza-CdR)
Goserelin
Aidiinjection
Oleaeuropaea
leafextract
Trastuzumab
GinsenosideRh2
hsa-miR-210
Atorvastatin Diethylstilbestrol
Progesterone
Hydroxycamptothecin(HCPT)
hsa-miR-335-3p
hsa-miR-1973Bromocriptine
hsa-miR-671-5pNarangin
Testosterone
Ascorbatehsa-miR-1246
Microcystin-LR(MC-LR)
Marinefungal
metabolite1386A
5-Fluorouracil
has-miR-4791has-miR-184
has-miR-543Arsenictrioxide
Temozolomidehas-miR-133b
Ibandronate
Proanthocyanin
Benzenehas-miR-133a
has-miR-134
has-miR-409-3p
has-miR-329has-miR-326 Testosterone
+1,25-Dihydroxyvitamin
D3Gemcitabine
Mistletoelectin-I
has-miR-615-3p
Glucose
Hesperidin
MorphineCatechinVitamin
D3 1,2,6-Tri-O-galloyl-beta-D-glucopyranose
Gefitinib
Vorinostat(SAHA)
5-aza-2′-deoxycytidine(5-Aza-CdR)
+4-phenylbutyric
acid(PBA)
DEmiRNA_upDEmiRNA_down
Small_molecule
(b)
Figure 7: The DEmiRNA-small molecular drug targets the interaction network involved in the osteogenic differentiation of DPSC (a) andBMSC (b).
18 BioMed Research International
receptor γ (PPARγ) [94]. It has still not been demonstrated ifthe proosteogenic or anti-inflammatory effects of the men-tioned small molecular drugs found in BMSCs exert the sameimpact in DPSCs. Nevertheless, since the selection of candi-dates is a result of multiply derived and highly overlappingcalculations and predictions employed in this study, we areleaving room for a confident extrapolation of the drug effectson the DPSCs as well.
Apart from discussing the main outcomes, it is notewor-thy to mention the limitations of this study. Although mRNAand lncRNA expression profiles related to the osteodifferen-tiation of DPSCs and BMSCs were available in public data-bases, they were not included in the analysis. Undoubtedlyuseful raw data from these datasets did not apply to the com-mon differentially expressed miRNAs in DPSC and BMSCosteodifferentiation. Also, analyzing mRNA and lncRNAexpression profiles would have required an entirely different,amiss the scope of the intended study.
The study design of the two analyzed datasets varied interms of experimental conditions. The experimental groupused to generate that the GSE138180 dataset was treatedby odontogenic differentiation medium, whereas the controlgroup was cultured in the nondifferentiating medium fortwo weeks. Even though the DPSCs in control were notstimulated to differentiate and they were therefore regardedas naive in the original study that generated GSE138180,the culturing conditions may have still left room for sponta-neous differentiation [24]. The authors interpreted theabsence of mineral nodes in the control group, which is astandard sign of the absence of osteogenic differentiation,as an absence of spontaneous differentiation altogether. Byall means, this presents sufficient evidence that no osteodif-ferentiation took place in the control group [24]. Neverthe-less, BMSCs can spontaneously differentiate to osteoblasts[95], which imposes a question if the DPSCs can do it too.
The experimental design of the study generated theGSE107279 compared the two weeks of post-differentiationwith day 0, hereby ensuring that the control group did notspontaneously differentiate. Hereby, the control groups inthe two datasets ‘nondifferentiated while not stimulated’ inGSE138180 and ‘nondifferentiated while prior to differentia-tion’ in GSE107279 were compared as peer groups. In thelack of further osteogenesis-relevant datasets for BMSCsand DPSCs and considering the argument on the nondiffer-entiated control group provided by the authors ofGSE138180, we carried out the comparative analysis of thetwo mentioned datasets. Optimally though, experimentalset up should be established with a control group at d0(without culturing and prior to any differentiation) and theexperimental group on d14 (after culturing in the osteodif-ferentiation medium).
In addition, it is important to mention that the osteogenicinduction media (50mg/mL ascorbic acid, 100 nmol/L dexa-methasone, and 10mmol/L β-glycerolphosphate) used forGSE138180 could either induce DPSCs towards the osteo-genic differentiation and form osteoblasts, or towards theodontogenic differentiation, hereby forming odontoblasts.The authors of GSE138180 regarded the odontogenic andosteogenic differentiation as the same process and reportedan odontogenic differentiation of DPSCs in their publication[24] and osteogenic differentiation in the resulting GEOdataset summary (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138180). In the future, potential confusionin investigating the osteogenic/odontogenic differentiationcould easily be resolved by assessing odontogenic biomarkerssuch as dentin matrix acid phosphoprotein 1 (DMP1), dentinsialophosphoprotein (DSPP), and matrix extracellular phos-phoglycoprotein (MEPE) [96]. To this day, much of theinterpretation of previous work has been limited by notassessing those differential markers [97–102]. Except for thisdifference, the genetic and epigenetic mechanisms involvedin the osteodifferentiation and odontodifferentiation ofDPSCs are common [96]. For the purpose of this study, weadopted the reported statement that DPSCs underwent oste-ogenic differentiation that was comparable to the osteogenicdifferentiation of BMSCs.
Availibility of only one time point—2 weeks of osteodif-ferentiation—for analysis of the DPSC-endpoint-bone inGSE138180 presents another limitation in assessing the grad-ual process of differentiation. Assessing genetic and epige-netic status over several time points could be crucial forunderstanding the DPSC differentiation dynamics [103].Analyzing further data points of the DPSC osteodifferentia-tion could be extremely helpful for their comparison withthe already available multiple time points of the BMSCosteodifferentiation.
Last but not least, this study presents computational pre-dictions based on the reported existing raw data. The predic-tive data have not been directly experimentally validated.Further validation of the biomarkers predicted in thisresearch could be performed by polymerase chain reaction(PCR) and western blotting assays. Despite the stated limita-tions, the biomarkers identified in the study provide potentialdirections for future surveys of genetic and epigenetic
Table 5: The 13 overlapping DEmiRNA-small molecular drugtarget interaction pairs between the DEmiRNA-small molecularinteraction networks of DPSC and BMSC osteodifferentiation.
DEmiRNAs dysregulated in both DPSCand BMSC osteodifferentiation
Small moleculartargets
hsa-miR-143-3pDocosahexaenoic
acid
hsa-miR-146b-5p
5-fluorouracil
Arsenic trioxide
Atorvastatin
Progesterone
hsa-miR-34c-5p
Arsenic trioxide
Curcumin
Glucose
hsa-miR-671-5p
5-fluorouracil
Bromocriptine
Microcystin-LR(MC-LR)
Narangin
Proanthocyanin
19BioMed Research International
Table 6: The targeting relationship between 19 overlapping small molecule drugs and their regulated DEmiRNAs, respectively, expressed inDPSC and BMSC osteodifferentiation process. These 19 overlapping small molecular drugs can not only regulate the DEmiRNAsdysregulated in DPSC osteodifferentiation but also regulate the DEmiRNAs dysregulated in BMSC osteodifferentiation.
Small moleculeRegulated DEmiRNAs involved in DPSC
osteodifferentiationRegulated DEmiRNAs involved in BMSC
osteodifferentiation
5-fluorouracil
hsa-miR-1246 hsa-miR-140-3p
hsa-miR-146b-5p hsa-miR-146b-5p
hsa-miR-184 hsa-miR-342-3p
hsa-miR-210 hsa-miR-3658
hsa-miR-4791 hsa-miR-378i
hsa-miR-671-5p hsa-miR-423-5p
hsa-miR-574-3p
hsa-miR-671-5p
Anthocyanin hsa-miR-335-5p hsa-miR-450a-5p
Arsenic trioxide
hsa-miR-133b hsa-miR-146b-5p
hsa-miR-146b-5p hsa-miR-34c-5p
hsa-miR-184
hsa-miR-210
hsa-miR-34c-5p
Ascorbate
hsa-miR-1246 hsa-miR-1972
hsa-miR-134
hsa-miR-1973
Atorvastatin
hsa-miR-146b-5p hsa-miR-146b-5p
hsa-miR-487a hsa-miR-224-5p
hsa-miR-548d-5p
Bromocriptine hsa-miR-671-5p hsa-miR-671-5p
Curcumin
hsa-miR-210 hsa-miR-34c-5p
hsa-miR-335-5p hsa-miR-450a-5p
hsa-miR-34c-5p
Docosahexaenoic acid
hsa-miR-1283 hsa-miR-141-3p
hsa-miR-143-3p hsa-miR-143-3p
hsa-miR-181a-5p hsa-miR-191-5p
hsa-miR-193b-3p
Ginsenoside Rh2
hsa-miR-210 hsa-miR-188-5p
hsa-miR-3195 hsa-miR-483-3p
hsa-miR-3656 hsa-miR-630
hsa-miR-370
hsa-miR-4284
Glucose
hsa-miR-133a hsa-miR-129-5p
hsa-miR-133b hsa-miR-199b-5p
hsa-miR-329 hsa-miR-342-5p
hsa-miR-34c-5p hsa-miR-34c-5p
hsa-miR-615-3p hsa-miR-369-3p
hsa-miR-508-3p
hsa-miR-520b
hsa-miR-525-5p
hsa-miR-548d-5p
Hesperidinhsa-miR-133b hsa-miR-188-5p
hsa-miR-450b-3p
Hydroxycamptothecin(HCPT)
hsa-miR-1246 hsa-miR-10a-5p
hsa-miR-1973 hsa-miR-135a-3p
20 BioMed Research International
biomarkers as well as regulatory mediators involved in oste-ogenic differentiation of DPSCs.
Eventually, the DPSCs and BMSCs appear to sharecommon DEmiRNAs and their targets, with cohesive out-comes on the genetic and epigenetic levels in terms of theosteodifferentiation process. This places them among com-mon targets that could be directly or indirectly influencedby the mentioned selected small molecule drug candidates.The established correlations provide a base for a betterunderstanding of the common molecular alterations duringthe osteogenic differentiation of DPSCs and BMSCs. Thosecould present an immense potential if used for tissue engi-neering purposes, especially drug delivery, herewith puta-tively contributing to the future therapeutical trends inbone regeneration.
5. Conclusions
Several miRNAs (miR-101-3p, miR-143-3p, miR-145-3p,miR-145-5p, miR-19a-3p, miR-34c-5p, miR-3607-3p, miR-378e, miR-671-3p, and miR-671-5p, miR-671-3p, and miR-671-5p), genes (REL, CCND1/2, IGF1R, THBS1, and ELK4),signaling pathways (TNF, mTOR, Hippo, neutrophin, and sig-naling pathways regulating pluripotency of stem cells), tran-scription factors (RUNX1, FOXA1, HIF1A, and MYC), andsmall molecular drugs (curcumin, docosahexaenoic acid(DHA), vitamin D3, arsenic trioxide, 5-fluorouracil (5-FU),and naringin) emerged as shared regulating factors duringthe osteogenic differentiation of DPSCs and BMSCs. The bio-markers and small molecular drugs identified in this studycould be used for the genetic/epigenetic manipulation and
drug delivery of DPSCs and therefore result in novel strategiesfor bone tissue engineering.
Data Availability
The data used to support the findings of this study are avail-able from the corresponding author upon reasonable request.
Conflicts of Interest
The authors declare that they have no conflict of interest.
Authors’ Contributions
Sebastian Gaus and Hanluo Li contributed equally as the firstauthor. Vuk Savkovic and Bernd Lethaus contributed equallyas the senior author. These three authors contributed equallyas the corresponding author: Dr. Lei Liu, Dr. Vuk Savkovic,and Prof. Dr. Bernd Lethaus.
Acknowledgments
Simin Li (CSC No.: 201608080010) and Hanluo Li (CSC No.:201308080064) were supported by the China ScholarshipCouncil (CSC) for doctor study at University Leipzig.
Supplementary Materials
Supplementary 1. File S1 The DEmiRNAs dysregulated in theosteodifferentiation of DPSC.
Supplementary 2. File S2 The DEmiRNAs dysregulated in theosteodifferentiation of BMSC.
Table 6: Continued.
Small moleculeRegulated DEmiRNAs involved in DPSC
osteodifferentiationRegulated DEmiRNAs involved in BMSC
osteodifferentiation
hsa-miR-335-3p hsa-miR-181a-2-3p
hsa-miR-370 hsa-miR-1972
hsa-miR-543 hsa-miR-224-3p
Microcystin-LR (MC-LR) hsa-miR-671-5p hsa-miR-671-5p
Mistletoe lectin-Ihsa-miR-331-3p hsa-miR-369-3p
hsa-miR-615-3p hsa-miR-491-3p
Naranginhsa-miR-671-5p hsa-miR-188-5p
hsa-miR-671-5p
Proanthocyanin
hsa-miR-133a hsa-miR-671-5p
hsa-miR-133b
hsa-miR-671-5p
Progesteronehsa-miR-146b-5p hsa-miR-146b-5p
hsa-miR-370 hsa-miR-525-5p
Vitamin D3
hsa-miR-133b hsa-miR-339-5p
hsa-miR-331-3p
hsa-miR-543
Vorinostat (SAHA)hsa-miR-134 hsa-miR-542-3p
hsa-miR-409-3p hsa-miR-574-3p
21BioMed Research International
Supplementary 3. File S3 The topological characteristics of allnodes in the 16 shared DEmiRNAs-target gene network.
Supplementary 4. File S4 The topological characteristics of allnodes in the DEmiRNAs-transcription factor interactionnetwork of DPSCs osteodifferentiation.
Supplementary 5. File S5 The topological characteristics of allnodes in the DEmiRNAs-transcription factor interactionnetwork of BMSCs osteodifferentiation.
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