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Background: Obesity has received increasing attention because of its widespread worldwide occurrence and many threats to health. Human adipose-derived mesenchymal stem cells (hADSCs) are a critical source of adipocytes. Long noncoding RNAs (lncRNAs) play pivotal roles in cell fate determination and differentiation. The objective of the present study was to identify and investigate the function and regulatory mechanism of lncRNAs on adipogenic differentiation of hADSCs., Methods: We used lncRNA arrays to identify the prominent differentially expressed lncRNAs before and after hADSC adipogenic differentiation and verified their biological function through antisense oligonucleotide knockdown or lentivirus overexpression. The adipogenic differentiation of hADSCs was assessed by oil red O staining as well as the mRNA and protein levels of adipogenic marker genes through qRT-PCR and western blot. Bioinformatic tool LncPro and immunofluorescence was performed to uncover the interaction between lnc13728 and ZBED3. WNT/β-catenin signaling pathway was evaluated by western blot and immunofluorescence., Results: The lncRNA arrays showed that lnc13728 expression was significantly upregulated after hADSC adipogenic differentiation and was correlated positively with the expression of the adipogenesis-related genes in human adipose tissue. Lnc13728 knockdown in hADSCs suppressed the expression of the adipogenesis-related genes at both mRNA and protein level and weakened lipid droplet production. Accordingly, lnc13728 overexpression enhanced hADSC adipogenic differentiation. Beyond that, lnc13728 co-localized with ZBED3 in the cytoplasm and regulated its expression positively. Downregulating ZBED3 had a negative effect on adipogenic differentiation, while the expression of WNT/β-catenin signaling pathway-related proteins was upregulated., Conclusions: Lnc13728 promotes hADSC adipogenic differentiation possibly by positively regulating the expression of ZBED3 which plays a role in inhibiting the WNT/β-catenin pathway.

Long noncoding RNAs (lncRNAs) have been implicated in a range of developmental processes and diseases, but the roles and mechanisms by which they act in adipogenic differentiation and adipose tissue biology are still unknown. By comparing the different expression patterns of lncRNAs before and after the adipocyte differentiation of human adipose-derived mesenchymal stem cells (hADSCs), we characterized a novel lncRNA, AC092834.1, which is significantly increased in preadipocytes. By gain- and loss-of-function experiments, we demonstrated that lncRNA AC092834.1 potentiated adipogenic differentiation through directly increasing the level of expression of DKK1, which competitively binds with LRP5 to inhibit the Wnt-β-catenin pathway and reduce the inhibition of adipogenesis by Wnt signaling. This finding provides novel mechanistic insights into a critical role for lncRNA AC092834.1 as a regulator of adipogenic differentiation, which expands our knowledge about the molecular mechanisms of obesity and other adipogenic differentiation-related disorders., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Nowadays, immune diseases are a large burden in healthcare. Mesenchymal stem cells (MSCs) have prominent ability in immunomodulation and have been applicated on treating many immune-related diseases. However, the clinical outcomes can be disparate and sometimes completely counterproductive beyond explanation of cell heterogeneity. The theory of immunomodulation plasticity in MSCs has then emerged to explain that MSCs can be induced into proinflammatory MSC1 or anti-inflammatory MSC2 responding to different immune environment. It would be safer and more efficient if we could induce MSCs into a certain immune phenotype, in most cases MSC2, prior to medical treatment. In this study, we screened and identified a classical FDA-approved drug, chlorzoxazone (CZ). Unlike traditional method induced by IFN-γ, CZ can induce MSC into MSC2 phenotype and enhance the immunosuppressive capacity without elevation of immunogenicity of MSCs. CZ-treated MSCs can better inhibit T cells activation and proliferation, promote expression of IDO and other immune mediators in vitro, and alleviate inflammatory infiltration and tissue damage in acute kidney injury rat model more effectively. Moreover, we discovered that CZ modulates phosphorylation of transcriptional factor forkhead box O3 (FOXO3) independent of classical AKT or ERK signaling pathways, to promote expression of downstream immune-related genes, therefore contributing to augmentation of MSCs immunosuppressive capacity. Our study established a novel and effective approach to induce MSC2, which is ready for clinical application.

Adolescent idiopathic scoliosis (AIS) is a complex, three dimensional deformity of the spine that commonly occurs in pubescent girls. Abnormal osteogenic differentiation of mesenchymal stem cells (MSCs) is implicated in the pathogenesis of AIS. However, the biological roles of long noncoding RNAs (lncRNAs) in the regulation of osteogenic differentiation of MSCs are unknown. Through microarray analyses of bone marrow (BM) MSCs from healthy donors and AIS patients, we identified 1483 differentially expressed lncRNAs in AIS BM-MSCs. We defined a novel lncAIS (gene symbol: ENST00000453347) is dramatically downregulated in AIS BM-MSCs. In normal BM-MSCs, lncAIS interacts with NF90 to promote HOXD8 mRNA stability that enhances RUNX2 transcription in BM-MSCs, leading to osteogenic differentiation of normal BM-MSCs. By contrast, lncAIS downregualtion in AIS BM-MSCs cannot recruit NF90 and abrogates HOXD8 mRNA stability, which impedes RUNX2 transcription for osteogenic differentiation. Thereby lncAIS downregualtion in BM-MSCs suppresses osteogenic differentiation that is implicated in the pathogenesis of AIS.

Background Context: Coexistence of abnormal skeletal growth and reduced bone mineral density in the context of adolescent idiopathic scoliosis (AIS) suggests disturbed bone metabolism existing in such patients. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of bone marrow mesenchymal stem cells (BM-MSCs) of AIS., Purpose: To explore the differential miRNA expression profile, Go (gene ontology) terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways in BM-MSCs of AIS and non-AIS controls were conducted using microarray approach and bioinformatics analyses., Study Design: miRNA microarray approach and bioinformatics analysis., Methods: The differentially expressed miRNAs (DEMs) of BM-MSCs from AIS patients compared with those from healthy individuals were analyzed using a microarray analysis. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the interaction network analysis of DEMs contained in significant pathways, 12 potential crucial miRNAs were selected for validation by RT-PCR., Results: The study identified 54 previously unrecognized DEMs (12 upregulated, 42 downregulated) in BM-MSCs from AIS patients. These miRNAs are involved in multiple biological processes, including small GTPase-mediated signal transduction, DNA-dependent transcription, cytokinesis, cell adhesion, transmembrane transport, response to hypoxia, etc. Pathway analysis of these new identified miRNAs revealed dysregulated MAPK signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, Notch signaling pathway, and ubiquitin-mediated proteolysis pathway, all of which have been reported to play important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, interaction networks analysis indicated that seven most significant central miRNAs, including miR-17-5p, miR-106a-5p, miR-106b-5p, miR-16-5p, miR-93-5p, miR-15a-5p, and miR-181b-5p may play essential roles in AIS pathogenesis and accompanied osteopenia., Conclusion: The current study reports the differential miRNAs expression profiles of BM-MSCs from AIS patients and related pathways for the first time. The identification of these candidate miRNAs provides a deep insight into the pathogenesis of AIS and the accompanying generalized osteopenia., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The generation of definitive endoderm (DE) cells in sufficient numbers is a prerequisite for cell-replacement therapy for liver and pancreatic diseases. Previously, we reported that human adipose-derived mesenchymal stem cells (hAMSCs) can be induced to DE lineages and subsequent functional cells. Clarifying the regulatory mechanisms underlying the fate conversion from hAMSCs to DE is helpful for developing new strategies to improve the differentiation efficiency from hAMSCs to DE organs. Long noncoding RNAs (lncRNAs) have been shown to play pivotal roles in developmental processes, including cell fate determination and differentiation. In this study, we profiled the expression changes of lncRNAs and found that antidifferentiation noncoding RNA (ANCR) was downregulated during the differentiation of both hAMSCs and embryonic stem cells (ESCs) to DE cells. ANCR knockdown resulted in the elevated expression of DE markers in hAMSCs, but not in ESCs. ANCR overexpression reduced the efficiency of hAMSCs to differentiate into DE cells. Inhibitor of DNA binding 2 (ID2) was notably downregulated after ANCR knockdown. ID2 knockdown enhanced DE differentiation, whereas overexpression of ID2 impaired this process in hAMSCs. ANCR interacts with RNA-binding polypyrimidine tract-binding protein 1 (PTBP1) to facilitate its association with ID2 mRNA, leading to increased ID2 mRNA stability. Thus, the ANCR/PTBP1/ID2 network restricts the differentiation of hAMSCs toward DE. Our work highlights the inherent discrepancies between hAMSCs and ESCs. Defining hAMSC-specific signaling pathways might be important for designing optimal differentiation protocols for directing hAMSCs toward DE.

Objective: Although adipocytes are the most abundant stromal cell component in breast cancer tissues, their interaction with breast cancer cells has been less investigated compared to cancer-associated fibroblasts or macrophages. Exosomes are a novel way of cell-cell communication and have been demonstrated to play an important role in various biological processes. However, to our knowledge, only a few studies have reported the effects of adipocyte exosomes on tumor development. Here, utilizing exosomes isolated from in vitro mesenchymal stromal/stem cell (MSC)-differentiated adipocytes, we systematically investigated this issue in a breast cancer model., Material and Methods: Exosomes were isolated from MSC-differentiated adipocytes and added to breast cancer cells MCF7. Cell proliferation was detected by MTS, and migration was analyzed by wound healing and transwell assay. An in vivo mouse xenograft model was used to evaluate MSC-differentiated adipocyte exosomes' contribution to tumor growth. Signaling pathway activation was evaluated by western blot and immunofluorescence staining., Results: We found MSC-differentiated adipocyte-derived exosomes are actively incorporated by breast cancer cell MCF7 and subsequently promote MCF7 proliferation and migration as well as protect MCF7 from serum derivation or chemotherapeutic drug-induced apoptosis in vitro. In the in vivo mouse xenograft model, depletion of exosomes reduces tumor-promoting effects of adipocytes. Transcriptomic analysis of MSC-differentiated adipocyte exosome-treated MCF7 identified several activated signaling pathways, among which we confirm the Hippo signaling pathway and found a blockade of this pathway leads to a reduced growth-promoting effect of adipocyte exosomes., Conclusion: Taken together, our findings provide new insights into the role of adipocyte exosomes in the tumor microenvironment.

As a promising candidate seed cell type in regenerative medicine, mesenchymal stem cells (MSCs) have attracted considerable attention. The unique capacity of MSCs to exert a regulatory effect on immunity in an autologous/allergenic manner makes them an attractive therapeutic cell type for immune disorders. In this review, we discussed the current knowledge of and advances in MSCs, including its basic biological properties, i.e., multilineage differentiation, secretome, and immunomodulation. Specifically, on the basis of our previous work, we proposed three new concepts of MSCs, i.e., "subtotipotent stem cell" hypothesis, MSC system, and "Yin and Yang" balance of MSC regulation, which may bring new insights into our understanding of MSCs. Furthermore, we analyzed data from the Clinical Trials database ( http://clinicaltrials.gov ) on registered clinical trials using MSCs to treat a variety of immune diseases, such as graft-versus-host disease, systemic lupus erythematosus, and multiple sclerosis. In addition, we highlighted MSC clinical trials in China and discussed the challenges and future directions in the field of MSC clinical application.

Cell transplantation holds considerable promise for end-stage liver diseases but identifying a suitable, transplantable cell type has been problematic. Here, we describe a novel type of mesenchymal stem cells (MSCs) from human adipose tissue. These cells are different from previously reported MSCs, they are in the euchromatin state with epigenetic multipotency, and express pluripotent markers MYC, KLF4, and GMNN. Most of the genes associated with germ layer specification are modified by H3K4me3 or co-modified by H3K4me3 and H3K27me3. We named this new type of MSCs as adult multipotent adipose-derived stem cells (M-ADSCs). Using a four-step nonviral system, M-ADSCs can be efficiently Induced into hepatocyte like cells with expression of hepatocyte markers, drug metabolizing enzymes and transporters, and the other basic functional properties including albumin (ALB) secretion, glycogen storage, detoxification, low-density lipoprotein intake, and lipids accumulation. In vivo both M-ADSCs-derived hepatoblasts and hepatocytes could form vascularized liver-like tissue, secrete ALB and express metabolic enzymes. Single-cell RNA-seq was used to investigate the important stages in this conversion. M-ADSCs could be converted to a functionally multipotent state during the preinduction stage without undergoing reprogramming process. Our findings provide important insights into mechanisms underlying cell development and conversion. Stem Cells Translational Medicine 2018;7:792-805., (© 2018 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

Study Design: Microarray approach and integrated gene network analysis., Objective: To explore the differential genetic expression profile, gene ontology terms, and Kyoto Encyclopedia of Genes and Genomes pathways in bone marrow mesenchymal stem cells (BM-MSCs) of idiopathic scoliosis (AIS) and non-AIS controls., Summary of Background Data: The pathogenesis of adolescent AIS and the accompanying generalized osteopenia remain unclear. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of BM-MSCs of AIS. Therefore, we hypothesized that MSCs may play a significant role in the etiology and pathogenesis of AIS., Methods: In this study, microarray analysis was used to identify differentially expressed genes (DEGs) of BM-MSCs from AIS patients compared with those from healthy individuals. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the gene signal transduction network analysis of DEGs contained in significant pathways, 24 potential crucial genes were selected for validation by reverse transcription polymerase chain reaction., Results: There are 1027 previously unrecognized DEGs in BM-MSCs from AIS patients. Pathway analysis revealed dysregulated mitogen-activated protein kinase (MAPK) signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway, ubiquitin-mediated proteolysis, and Notch signaling pathway, all of which have been reported to play an important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, gene signal transduction networks analysis indicated that mitogen-activated protein kinase kinase 1 (MAP2K1), SMAD family member 3 (SMAD3), homeobox C6 (HOXC6), heat shock 70kDa protein 6 (HSPA6), general transcription factor IIi (GTF2I), CREB binding protein (CREBBP), phosphoinositide-3-kinase, regulatory subunit 2 (PIK3R2), and dual specificity phosphatase 2 (DUSP2) may play essential roles in AIS pathogenesis and accompanied osteopenia., Conclusion: This study reports the differential genes expression profiles of BM-MSCs from AIS patients and related potential pathways for the first time. These previously unrecognized genes and molecular pathways might play a significant role in not only the causal mechanism of osteopenia in AIS, but also the AIS initiation and development. The identification of these candidate genes provides novel insight into the underlying etiological mechanisms of AIS., Level of Evidence: N/A.

Background: In tumor microenvironment, a continuous cross-talk between cancer cells and other cellular components is required to sustain tumor progression. Accumulating evidence suggests that exosomes, a novel way of cell communication, play an important role in such cross-talk. Exosomes could facilitate the direct intercellular transfer of proteins, lipids, and miRNA/mRNA/DNAs between cells. Since mesenchymal stem cells (MSCs) can be attracted to tumor sites and become an important component of the tumor microenvironment, there is an urgent need to reveal the effect of tumor exosomes on MSCs and to further explore the underlying molecular mechanisms., Methods: Exosomes were harvested from lung cancer cell line A549 and added to MSCs. Secretion of inflammation-associated cytokines in exosome-treated MSCs were analyzed by RT-PCR and ELISA. The growth-promoting effect of exosome-treated MSCs on lung tumor cells was evaluated by in vivo mouse xenograft model. Signaling pathway involved in exosomes-treated MSCs was detected by PCR array of human toll-like receptor signaling pathway, RT-PCR, and Western blot., Results: Data showed that lung tumor cell A549-derived exosomes could induce a pro-inflammatory phenotype in MSCs named P-MSCs, which have significantly elevated secretion of IL-6, IL-8, and MCP-1. P-MSCs possess a greatly enhanced ability in promoting lung tumor growth in mouse xenograft model. Analysis of the signaling pathways in P-MSCs revealed a fast triggering of NF-κB. Genetic ablation of Toll-like receptor 2 (TLR2) by siRNA and TLR2-neutralizing antibody could block NF-κB activation by exosomes. We further found that Hsp70 present on the surface of lung tumor exosomes contributed to the induction of P-MSCs by A549 exosomes., Conclusions: Our studies suggest a novel mechanism by which lung tumor cell-derived exosomes induce pro-inflammatory activity of MSCs which in turn get tumor supportive characteristics.

Emerging evidence indicates that microRNAs (miRNA, or miR) play vital roles in regulating osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Elucidation of the molecular mechanisms that govern BMSCs osteogenic differentiation is of paramount importance for improving the treatment of bone-related diseases. In our current study, we investigated the role of miR-23a in BMSCs osteogenesis. Our results revealed that miR-23a was significantly downregulated during osteogenic differentiation. Overexpression of miR-23a inhibited osteogenic differentiation of hBMSCs in vitro, whereas downregulation of miR-23a enhanced the process. Target prediction analysis and dual luciferase reporter assays confirmed that low-density lipoprotein (LDL)-receptor-related protein 5 (LRP5) was a direct target of miR-23a. Furthermore, knockdown of LRP5 inhibited osteogenic differentiation of hBMSCs, similar to the effect observed in upregulation miR-23a. Our data indicate that miR-23a plays an inhibitory role in osteogenic differentiation of hBMSCs, which may act by targeting LRP5., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

C/EBPα is a critical transcriptional regulator of adipogenesis. How C/EBPα transcription is itself regulated is poorly understood, however, and remains a key question that needs to be addressed for a complete understanding of adipogenic development. Here, we identify a lncRNA, ADINR (adipogenic differentiation induced noncoding RNA), transcribed from a position ∼450 bp upstream of the C/EBPα gene, that orchestrates C/EBPα transcription in vivo. Depletion of ADINR leads to a severe adipogenic defect that is rescued by overexpression of C/EBPα. Moreover, we reveal that ADINR RNA specifically binds to PA1 and recruits MLL3/4 histone methyl-transferase complexes so as to increase H3K4me3 and decrease H3K27me3 histone modification in the C/EBPα locus during adipogenesis. These results show that ADINR plays important roles in regulating the differentiation of human mesenchymal stem cells into adipocytes by modulating C/EBPα in cis., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

MiRNAs have been identified in various plants and animals where they function in post-transcriptional regulation. Although studies revealed that dexamethasone play a pivotal role in the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs), the identification of specific miRNAs and their regulatory roles in this process remain poorly defined. In this study, microarrays were used to analyze the miRNA expression profile of dexamethasone-induced hBMSCs derived from three donors, and RT-PCRs were used to confirm the microarray results. Nine upregulated miRNAs and seven downregulated miRNAs were identified. The putative target genes of these miRNAs were predicted using bioinformatics analysis. Subsequently, we focused our attention on the functional analysis of an upregulated miRNA, miR-23a. Overexpression of miR-23a inhibited osteogenic differentiation of hBMSCs at the cellular, mRNA, and protein levels. The results of our study provide an experimental basis for further research on miRNAs functions during osteogenic differentiation of dexamethasone-induced hBMSCs., (© 2014 Wiley Periodicals, Inc.)

Bone and fat cells share a common progenitor, stromal/mesenchymal stem cells (MSCs), that can differentiate into osteoblasts or adipocytes. Osteogenesis and adipogenesis of MSCs maintain homeostasis under physiological conditions. The disruption of this homeostasis leads to bone-related metabolic diseases. For instance, reduction in bone formation, which is usually accompanied by an increase in bone marrow adipogenesis, occurs with aging, immobility, or osteoporosis. Thus, it is crucial to gain an understanding of how osteogenic and adipogenic lineages of MSCs are regulated. Here, we present evidence that let-7 is a positive regulator of bone development. Using gain- and loss-of-function approaches, we demonstrate that let-7 markedly promotes osteogenesis and suppresses adipogenesis of MSCs in vitro. Moreover, let-7 could promote ectopic bone formation of MSCs in vivo. Subsequent studies further demonstrated that let-7's effects are mediated through the repression of high-mobility group AT-hook 2 (HMGA2) expression. RNAi depletion of HMGA2 could also enhance osteogenesis and repress adipogenesis. Overall, we found a novel role of let-7/HMGA2 axis in regulating the balance of osteogenesis and adipogenesis of MSCs. Thus, let-7 can be used as a novel therapeutic target for disorders that are associated with bone loss and adipocyte accumulation.

Mesenchymal stem cells (MSCs) can differentiate into several distinct cell types, including osteoblasts and adipocytes. The balance between osteogenic and adipogenic differentiation is disrupted in several osteogenic-related disorders, such as osteoporosis. So far, little is known about the molecular mechanisms that drive final lineage commitment of MSCs. In this study, we revealed that miR-17-5p and miR-106a have dual functions in the modulation of human adipose-derived mesenchymal stem cells (hADSCs) commitment by gain- and loss-of-function assays. They could promote adipogenesis and inhibit osteogenesis. Luciferase reporter assay, western blot and ELISA suggested BMP2 was a direct target of miR-17-5p and miR-106a. Downregulation of endogeneous BMP2 by RNA interference suppressed osteogenesis and increased adipogenesis, similar to the effect of miR-17-5p and miR-106a upregulation. Moreover, the inhibitory effects of miR-17-5p on osteogenic and adipogenic differentiation of hADSCs could be reversed by BMP2 RNA interference. In conclusion, miR-17-5p and miR-106a regulate osteogenic and adipogenic lineage commitment of hADSCs by directly targeting BMP2, and subsequently decreased osteogenic TAZ, MSX2 and Runx2, and increased adipogenic C/EBPα and PPARγ., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Although the epithelial-mesenchymal transition (EMT) is a normal process that occurs during development, it is thought to be associated with cancer progression and metastasis. Emerging evidence links mesenchymal stem cells (MSCs) in the tumor microenvironment with the occurrence of EMT in cancer progression. In this study, the human breast cancer cell line MCF7 was co-cultured with human adipose-derived MSCs (hAD-MSCs) in a transwell system. Co-cultured cells were analyzed for changes in cellular morphology, EMT markers, protein expression and tumor characteristics. We found that co-cultured MCF7 cells underwent EMT and established a stable mesenchymal phenotype after prolonged co-culturing. Here, we demonstrate that paracrine transforming growth factor-β1 (TGF-β1) secreted by hAD-MSCs regulated the establishment of EMT in MCF7 cells by targeting the ZEB/miR-200 regulatory loop. The downregulation of paracrine TGF-β1 levels can inhibit and reverse the EMT progress by downregulating ZEB1/2 and upregulating miR-200b and miR-200c. The maintenance of a stable mesenchymal state by MCF7 cells required the establishment of autocrine TGF-β signaling to drive and sustain ZEB expression, which had been initiated by the prolonged co-culturing with hAD-MSCs. These results suggest that MSCs may promote breast cancer metastasis by stimulating and facilitating the EMT process.

Mesenchmal stem cells (MSCs) can be differentiated into either adipocytes or osteoblasts, and a reciprocal relationship exists between adipogenesis and osteogenesis. Multiple transcription factors and signaling pathways have been reported to regulate adipogenic or osteogenic differentiation, respectively, yet the molecular mechanism underlying the cell fate alteration between adipogenesis and osteogenesis still remains to be illustrated. MicroRNAs are important regulators in diverse biological processes by repressing protein expression of their targets. Here, miR-22 was found to regulate adipogenic and osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hADMSCs) in opposite directions. Our data showed that miR-22 decreased during the process of adipogenic differentiation but increased during osteogenic differentiation. On one hand, overexpression of miR-22 in hADMSCs could inhibit lipid droplets accumulation and repress the expression of adipogenic transcription factors and adipogenic-specific genes. On the other hand, enhanced alkaline phosphatase activity and matrix mineralization, as well as increased expression of osteo-specific genes, indicated a positive role of miR-22 in regulating osteogenic differentiation. Target databases prediction and validation by Dual Luciferase Reporter Assay, western blot, and real-time polymerase chain reaction identified histone deacetylase 6 (HDAC6) as a direct downstream target of miR-22 in hADMSCs. Inhibition of endogenous HDAC6 by small-interfering RNAs suppressed adipogenesis and stimulated osteogenesis, consistent with the effect of miR-22 overexpression in hADMSCs. Together, our results suggested that miR-22 acted as a critical regulator of balance between adipogenic and osteogenic differentiation of hADMSCs by repressing its target HDAC6.

Elucidation of the molecular mechanisms governing human adipose-derived mesenchymal stem cells (hASCs) osteogenic differentiation is of great importance for improving the treatment of bone-related diseases. In this study, we examined the role of microRNA (miR)-100 on the osteogenesis of hASCs. Overexpression of miR-100 inhibited osteogenic differentiation of hASCs in vitro, whereas downregulation of miR-100 enhanced the process. Target prediction analysis and dual luciferase report assay confirmed that bone morphogenetic protein receptor type II (BMPR2) was a direct target of miR-100. Furthermore, knockdown of BMPR2 by RNA interference inhibited osteogenic differentiation of hASCs, similar as the effect of upregulation miR-100. Taken together, our findings imply that miR-100 plays a negative role in osteogenic differentiation and might act through targeting BMPR2., (Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

Osteoporosis is characterized by deterioration of bone microarchitecture and low bone mass. One of the primary causes of osteoporosis is the decrease in the osteogenic differentiation of mesenchymal stem cells (MSCs). Tissue engineering therapy with genetically modified MSCs has attracted much attention in the study of bone regeneration. In this study, we found that the expression level of miR-450b was upregulated during osteogenic differentiation of human adipose-derived mesenchymal stem cells (hADSCs). To explore the effect of miR-450b on the osteogenesis of hADSCs, we performed a series of gain- and loss-of-function analyses and demonstrated that miR-450b not only promoted the process of hADSC differentiation to osteoblasts in vitro but also enhanced ectopic bone formation in vivo. Bone morphogenetic protein 3 (BMP3), the most abundant BMP member in bone, was identified as a direct target of miR-450b. Downregulation of the endogenous expression of BMP3 could mimic the effect of miR-450b upregulation on the osteogenic differentiation of hADSCs. Overall, our study first demonstrated that a novel microRNA miR-450b was essential for hADSC differentiation, which could promote osteogenic differentiation in vitro and enhance bone formation in vivo by directly suppressing BMP3. [ABSTRACT FROM AUTHOR]

Study Design: Microarray approach and integrated gene network analysis.Objective: To explore the differential genetic expression profile, gene ontology terms, and Kyoto Encyclopedia of Genes and Genomes pathways in bone marrow mesenchymal stem cells (BM-MSCs) of idiopathic scoliosis (AIS) and non-AIS controls.Summary Of Background Data: The pathogenesis of adolescent AIS and the accompanying generalized osteopenia remain unclear. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of BM-MSCs of AIS. Therefore, we hypothesized that MSCs may play a significant role in the etiology and pathogenesis of AIS.Methods: In this study, microarray analysis was used to identify differentially expressed genes (DEGs) of BM-MSCs from AIS patients compared with those from healthy individuals. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the gene signal transduction network analysis of DEGs contained in significant pathways, 24 potential crucial genes were selected for validation by reverse transcription polymerase chain reaction.Results: There are 1027 previously unrecognized DEGs in BM-MSCs from AIS patients. Pathway analysis revealed dysregulated mitogen-activated protein kinase (MAPK) signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway, ubiquitin-mediated proteolysis, and Notch signaling pathway, all of which have been reported to play an important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, gene signal transduction networks analysis indicated that mitogen-activated protein kinase kinase 1 (MAP2K1), SMAD family member 3 (SMAD3), homeobox C6 (HOXC6), heat shock 70kDa protein 6 (HSPA6), general transcription factor IIi (GTF2I), CREB binding protein (CREBBP), phosphoinositide-3-kinase, regulatory subunit 2 (PIK3R2), and dual specificity phosphatase 2 (DUSP2) may play essential roles in AIS pathogenesis and accompanied osteopenia.Conclusion: This study reports the differential genes expression profiles of BM-MSCs from AIS patients and related potential pathways for the first time. These previously unrecognized genes and molecular pathways might play a significant role in not only the causal mechanism of osteopenia in AIS, but also the AIS initiation and development. The identification of these candidate genes provides novel insight into the underlying etiological mechanisms of AIS.Level Of Evidence: N/A. [ABSTRACT FROM AUTHOR]

Neural stem cells (NSCs) are ideal candidates in stem cell-based therapy for neurodegenerative diseases. However, it is unfeasible to get enough quantity of NSCs for clinical application. Generation of NSCs from human adipose-derived mesenchymal stem cells (hAD-MSCs) will provide a solution to this problem. Currently, the differentiation of hAD-MSCs into highly purified NSCs with biological functions is rarely reported. In our study, we established a three-step NSC-inducing protocol, in which hAD-MSCs were induced to generate NSCs with high purity after sequentially cultured in the pre-inducing medium (Step1), the N2B27 medium (Step2), and the N2B27 medium supplement with basic fibroblast growth factor and epidermal growth factor (Step3). These hAD-MSC-derived NSCs (adNSCs) can form neurospheres and highly express Sox1, Pax6, Nestin, and Vimentin; the proportion was 96.1%±1.3%, 96.8%±1.7%, 96.2%±1.3%, and 97.2%±2.5%, respectively, as detected by flow cytometry. These adNSCs can further differentiate into astrocytes, oligodendrocytes, and functional neurons, which were able to generate tetrodotoxin-sensitive sodium current. Additionally, we found that the neural differentiation of hAD-MSCs were significantly suppressed by Sox1 interference, and what's more, Step1 was a key step for the following induction, probably because it was associated with the initiation and nuclear translocation of Sox1, an important transcriptional factor for neural development. Finally, we observed that bone morphogenetic protein signal was inhibited, and Wnt/β-catenin signal was activated during inducing process, and both signals were related with Sox1 expression. In conclusion, we successfully established a three-step inducing protocol to derive NSCs from hAD-MSCs with high purity by Sox1 activation. These findings might enable to acquire enough autologous transplantable NSCs for the therapy of neurodegenerative diseases in clinic. [ABSTRACT FROM AUTHOR]