Depletion of HOXA5 inhibits the osteogenic differentiation and proliferation potential of stem cells from the apical papilla

Mesenchymal Stem Cell-Derived Extracellular Vesicles: The Novel Therapeutic Option for Regenerative Dentistry

Dental mesenchymal stem cells (MSCs) are characterized by unlimited self-renewal ability and high multidirectional differentiation potential. Since dental MSCs can be easily isolated and exhibit a high capability to differentiate into odontogenic cells, they are considered as attractive therapeutic agents in regenerative dentistry. Recently, MSC-derived extracellular vesicles (MSC-EVs) have attracted widespread attention as carriers for cell-free therapy due to their potential functions. Many studies have shown that MSC-EVs can mediate microenvironment at tissue damage site, and coordinate the regeneration process. Additionally, MSC-EVs can mediate intercellular communication, thus affecting the phenotypes and functions of recipient cells. In this review, we mainly summarized the types of MSCs that could be potentially applied in regenerative dentistry, the possible molecular cargos of MSC-EVs, and the major effects of MSC-EVs on the therapeutic induction of osteogenic differentiation.

Aberrant DNA methylation impacts HOX genes expression in bone marrow mesenchymal stromal cells of myelodysplastic syndromes and de novo acute myeloid leukemia

DNA methylation, a major biological process regulating the transcription, contributes to the pathophysiology of hematologic malignancies, and hypomethylating agents are commonly used to treat myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). In these diseases, bone marrow mesenchymal stromal cells (MSCs) play a key supportive role through the production of various signals and interactions. The DNA methylation status of MSCs, likely to reflect their functionality, might be relevant to understand their contribution to the pathophysiology of these diseases. Consequently, the aim of our study was to analyze the modifications of DNA methylation profiles of MSCs induced by MDS or AML. MSCs from MDS/AML patients were characterized via 5-methylcytosine quantification, gene expression profiles of key regulators of DNA methylation, identification of differentially methylated regions (DMRs) by methylome array, and quantification of DMR-coupled genes expression. MDS and AML-MSCs displayed global hypomethylation and under-expression of DNMT1 and UHRF1. Methylome analysis revealed aberrant methylation profiles in all MDS and in a subgroup of AML-MSCs. This aberrant methylation was preferentially found in the sequence of homeobox genes, especially from the HOX family (HOXA1, HOXA4, HOXA5, HOXA9, HOXA10, HOXA11, HOXB5, HOXC4, and HOXC6), and impacted on their expression. These results highlight modifications of DNA methylation in MDS/AML-MSCs, both at global and focal levels dysregulating the expression of HOX genes well known for their involvement in leukemogenesis. Such DNA methylation in MSCs could be the consequence of the malignant disease or could participate in its development through defective functionality or exosomal transfer of HOX transcription factors from MSCs to hematopoietic cells.

HOXA5 Is Recognized as a Prognostic-Related Biomarker and Promotes Glioma Progression Through Affecting Cell Cycle

Glioma is malignant tumor derives from glial cells in the central nervous system. High-grade glioma shows aggressive growth pattern, and conventional treatments, such as surgical removal and chemo-radiotherapy, archive limitation in the interference of this process. In this work, HOXA5, from the HOX family, was identified as a glioma cell proliferation-associated factor by investigating its feature in the TCGA and CGGA data set. High HOXA5 expression samples contain unfavorable clinical features of glioma, including IDH wild type, un-methylated MGMT status, non-codeletion 1p19q status, malignant molecular subtype. Survival analysis indicates that high HOXA5 expression samples are associated with worse clinical outcome. The CNVs and SNPs profile difference further confirmed the enrichment of glioma aggressive related biomarkers. In the meantime, the activation of DNA damage repair-related pathways and TP53-related pathways is also related to HOXA5 expression. In cell lines, U87MG and U251, by interfering HOXA5 expression significantly inhibit glioma progression and apoptosis, and cell cycle is arrested at the G2/M phase. Collectively, increased HOXA5 expression can promote glioma progression via affecting glioma cell proliferation.

MiR-196a promoted cell migration, invasion and the epithelial-mesenchymal transition by targeting HOXA5 in osteosarcoma

INTRODUCTION

Osteosarcoma (OS), aggressive neoplasms of the bone, is the most common primary bone cancer in children. MiR-196a usually low expressed in several tumors and its functions in osteosarcoma still unclear.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to assess the expression of miR-196a and the HOXA5. Cell metastasis and epithelial-mesenchymal transition (EMT) abilities were assessed using Transwell and western blot. The dual luciferase reporter assay was carried out to verify whether miR-196a directly targeted the 3'-untranslated region (UTR) of HOXA5 mRNA.

RESULTS

MiR-196a was overexpressed and HOXA5 was low expressed in osteosarcoma versus the non-tumor tissues and normal cell lines. Upregulation of miR-196a or downregulation of HOXA5 was associated with worse outcome of osteosarcoma patients. MiR-196a enhanced cell migration, invasion and EMT by regulating the expression of HOXA5 through directly targeting the 3'-UTR of its mRNA in osteosarcoma. HOXA5 partially reversed roles of miR-196a on metastasis and EMT in osteosarcoma.

CONCLUSIONS

MiR-196a promoted cell metastasis and EMT by targeting the 3'-UTR of HOXA5 mRNA in osteosarcoma. The newly identified miR-196a/HOXA5 axis provides novel insight into the pathogenesis of osteosarcoma.

Differential circular RNA expression profiling during osteogenic differentiation of stem cells from apical papilla

Aim: This study aimed to investigate the distinct expression pattern of circular RNAs (circRNAs) in stem cells from apical papilla (SCAPs) during osteogenesis. Materials & methods: Isolated SCAPs were cultured in growth medium or osteogenic medium, respectively. Total RNA was extracted and submitted to RNA-sequencing. Expression profiles of circRNAs and constructed circRNA–miRNA–mRNA networks were determined. Results: A total of 333 unregulated circRNAs and 317 downregulated circRNAs in osteogenic differentiation were detected. Bioinformatics analysis identified that several biological pathways may be associated with osteogenic differentiation of SCAPs. Moreover, ten circRNAs, 21 miRNAs and 19 mRNAs were selected to construct competing endogenous RNA networks. Conclusion: This study revealed that expression profiles of circRNAs were significantly altered and specific circRNAs might function as competing endogenous RNAs in SCAPs during osteogenic differentiation.

Analysis of the characteristics and expression profiles of coding and noncoding RNAs of human dental pulp stem cells in hypoxic conditions

BACKGROUND

Human dental pulp stem cell (DPSC)-mediated regenerative endodontics is a promising therapy for damaged teeth; however, the hypoxic environment in root canals can affect tissue regeneration. In this study, we investigate the characteristics and possible regulatory mechanisms of DPSC function under hypoxic conditions.

METHODS

Human DPSCs were cultured under normoxia (20% O₂) and hypoxia (3% O₂). DPSC proliferation and osteo/odontogenic differentiation potential were assessed by Cell Counting Kit-8 (CCK8) assay, carboxyfluorescein succinimidyl ester (CFSE) assay, alkaline phosphatase (ALP) activity, Alizarin red staining, real-time RT-PCR assays, and western blot analysis. Microarray and bioinformatic analyses were performed to investigate the differences in the mRNA, lncRNA, and miRNA expression profiles of DPSCs.

RESULTS

DPSCs exhibited a more powerful proliferation ability and lower osteo/odontogenic differentiation potential in hypoxic conditions. A total of 60 mRNAs (25 upregulated and 35 downregulated), 47 lncRNAs (20 upregulated and 27 downregulated), and 14 miRNAs (7 upregulated and 7 downregulated) in DPSCs were differentially expressed in the hypoxia group compared with the normoxia group. Bioinformatic analysis identified that 7 mRNAs (GRPR, ERO1L, ANPEP, EPHX1, PGD, ANGPT1, and NQO1) and 5 lncRNAs (AF085958, AX750575, uc002czn.2, RP3-413H6.2, and six-twelve leukemia (STL)) may be associated with DPSCs during hypoxia according to CNC network analysis, while 28 mRNAs (including GYS1, PRKACB, and NQO1) and 13 miRNAs (including hsa-miR-3916 and hsa-miR-192-5p) may be involved according to miRNA target gene network analysis. The depletion of one candidate lncRNA, STL, inhibited the osteo/odontogenic differentiation potentials of DPSCs.

CONCLUSIONS

Our results revealed that hypoxia could enhance the proliferation ability and impair the osteo/odontogenic differentiation potential of DPSCs in vitro. Furthermore, our results identified candidate coding and noncoding RNAs that could be potential targets for improving DPSC function in regenerative endodontics and lead to a better understanding of the mechanisms of hypoxia's effects on DPSCs.