The protective effects of microRNA-26a in steroid-induced osteonecrosis of the femoral head by repressing EZH2

Noncoding RNAs: the crucial role of programmed cell death in osteoporosis

Osteoporosis is the most common skeletal disease characterized by an imbalance between bone resorption and bone remodeling. Osteoporosis can lead to bone loss and bone microstructural deterioration. This increases the risk of bone fragility and fracture, severely reducing patients' mobility and quality of life. However, the specific molecular mechanisms involved in the development of osteoporosis remain unclear. Increasing evidence suggests that multiple noncoding RNAs show differential expression in the osteoporosis state. Meanwhile, noncoding RNAs have been associated with an increased risk of osteoporosis and fracture. Noncoding RNAs are an important class of factors at the level of gene regulation and are mainly involved in cell proliferation, cell differentiation, and cell death. Programmed cell death is a genetically-regulated form of cell death involved in regulating the homeostasis of the internal environment. Noncoding RNA plays an important role in the programmed cell death process. The exploration of the noncoding RNA-programmed cell death axis has become an interesting area of research and has been shown to play a role in many diseases such as osteoporosis. In this review, we summarize the latest findings on the mechanism of noncoding RNA-mediated programmed cell death on bone homeostasis imbalance leading to osteoporosis. And we provide a deeper understanding of the role played by the noncoding RNA-programmed cell death axis at the gene regulatory level of osteoporosis. We hope to provide a unique opportunity to develop novel diagnostic and therapeutic approaches for osteoporosis.

Novel insights of EZH2-mediated epigenetic modifications in degenerative musculoskeletal diseases

Degenerative musculoskeletal diseases (Osteoporosis, Osteoarthritis, Degenerative Spinal Disease and Sarcopenia) are pathological conditions that affect the function and pain of tissues such as bone, cartilage, and muscles, and are closely associated with ageing and long-term degeneration. Enhancer of zeste homolog 2 (EZH2), an important epigenetic regulator, regulates gene expression mainly through the PRC2-dependent trimethylation of histone H3 at lysine 27 (H3K27me3). Increasing evidence suggests that EZH2 is involved in several biological processes closely related to degenerative musculoskeletal diseases, such as osteogenic-adipogenic differentiation of bone marrow mesenchymal stem cells, osteoclast activation, chondrocyte functional status, and satellite cell proliferation and differentiation, mainly through epigenetic regulation (H3K27me3). Therefore, the synthesis and elucidation of the role of EZH2 in degenerative musculoskeletal diseases have attracted increasing attention. In addition, although EZH2 inhibitors have been approved for clinical use, whether they can be repurposed for the treatment of degenerative musculoskeletal diseases needs to be considered. Here, we reviewed the role of EZH2 in the development of degenerative musculoskeletal diseases and brought forward prospects of its pharmacological inhibitors in the improvement of the treatment of the diseases.

microRNAs delivered by small extracellular vesicles in MSCs as an emerging tool for bone regeneration

Bone regeneration is a dynamic process that involves angiogenesis and the balance of osteogenesis and osteoclastogenesis. In bone tissue engineering, the transplantation of mesenchymal stem cells (MSCs) is a promising approach to restore bone homeostasis. MSCs, particularly their small extracellular vesicles (sEVs), exert therapeutic effects due to their paracrine capability. Increasing evidence indicates that microRNAs (miRNAs) delivered by sEVs from MSCs (MSCs-sEVs) can alter gene expression in recipient cells and enhance bone regeneration. As an ideal delivery vehicle of miRNAs, MSCs-sEVs combine the high bioavailability and stability of sEVs with osteogenic ability of miRNAs, which can effectively overcome the challenge of low delivery efficiency in miRNA therapy. In this review, we focus on the recent advancements in the use of miRNAs delivered by MSCs-sEVs for bone regeneration and disorders. Additionally, we summarize the changes in miRNA expression in osteogenic-related MSCs-sEVs under different microenvironments.

Functional micro-RNA drugs acting as a fate manipulator in the regulation of osteoblastic death

Bone loss is prevalent in clinical pathological phenomena such as osteoporosis, which is characterized by decreased osteoblast function and number, increased osteoclast activity, and imbalanced bone homeostasis. However, current treatment strategies for bone diseases are limited. Regulated cell death (RCD) is a programmed cell death pattern activated by the expression of specific genes in response to environmental changes. Various studies have shown that RCD is closely associated with bone diseases, and manipulating the death fate of osteoblasts could contribute to effective bone treatment. Recently, microRNA-targeting therapy drugs have emerged as a potential solution because of their precise targeting, powerful curative effect, and limited side effects. Nevertheless, their clinical application is limited by their inherent instability, easy enzymatic degradation, and poor membrane penetrability. To address this challenge, a self-assembling tetrahedral DNA nanostructure (TDN)-based microRNA (Tmi) delivery system has been proposed. TDN features excellent biocompatibility, cell membrane penetrability, serum stability, and modification versatility, making it an ideal nucleic acid carrier for miRNA protection and intracellular transport. Once inside cells, Tmi can dissociate and release miRNAs to manipulate key molecules in the RCD signaling pathway, thereby regulating bone homeostasis and curing diseases caused by abnormal RCD activation. In this paper, we discuss the impact of the miRNA network on the initiation and termination of four critical RCD programs in bone tissues: apoptosis, autophagy, pyroptosis, and ferroptosis. Furthermore, we present the Tmi delivery system as a miRNA drug vector. This provides insight into the clinical translation of miRNA nucleic acid drugs and the application of miRNA drugs in bone diseases.

Lipid metabolism analysis for peripheral blood in patients with alcoholinduced and steroidinduced osteonecrosis of the femoral head

OBJECTIVES

Osteonecrosis of the femoral head (ONFH), also known as vascular necrosis of the femoral head, is combined with lipid metabolism disorders in most patients. This study aims to explore the lipid metabolism profiles in different subtypes of ONFH.

METHODS

The subjects were divided into an alcohol-induced osteonecrosis of the femoral head (AONFH) group, a steroid-induced osteonecrosis of the femoral head (SONFH) group, and a normal control (NC) group (n=16, 29, and 32, respectively). Ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) was used to detect the lipidomics analysis in the peripheral blood samples of subjects and identify the underlying biomarkers. The samples were preprocessed, the partial least squares discriminant analysis (PLS-DA) was adopted, and the variable importance for the projection (VIP) values were calculated to measure the expression pattern of each lipid metabolite and observe the influence and explanatory power of the expression pattern of each lipid metabolite on the classification and discrimination between the different groups. The lipid metabolites with fold change (FC)>2, P<0.05 and VIP>1 in the different groups were screened as differential lipids. Among them, the differential lipids co-existing in the AONFH group and the SONFH group were regarded as common differential lipids for ONFH, and the differential lipids that exist separately were regarded as specific differential lipids in the AONFH group or the SONFH group. Binary logistic regression was used to evaluate the diagnostic value of differential lipid metabolites on the basis of the receiver operator characteristic (ROC) curve analysis. Based on the disease stage information, the correlation between the differential lipids and the disease stage was analyzed in the AONFH group and the SONFH group.

RESULTS

In this study, 1 358 lipid metabolites were detected in each plasma sample. Compared with the NC group, there were significant difference in the expression patterns of lipid metabolism profiles in the AONFH group and the SONFH group. A total of 62 and 64 differential lipid metabolites were screened in the AONFH and SONFH patients (FC>2, P<0.05, VIP>1) respectively, and these differential lipids were mainly up-regulated in the disease samples. Nine differential lipid metabolites were further identified, which were shared by the AONFH group and the SONFH group; the area under the curve (AUC) in 6 kinds of lipid components was greater than 0.7, including 1-myristoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine, hypoxanthin, serotonin, PE (19:0/22:5), PE (19:0/22:5), and cholest-5-en-3-yl beta-D-glucopyranosiduronic acid. Fifty-three specific differential lipid metabolites were identified in the AONFH group, and 55 specific differential lipid metabolites were identified in the SONFH group. The AUC in 6 kinds of lipid components was greater than 0.9, including 1D-myo-Inositol 1,2-cyclic phosphate, L-pyroglutamic acid, DL-carnitine, 8-amino-7-oxononanoic acid, Clobetasol, and presqualene diphosphate. In the AONFH group, there were 9 differential lipid metabolites related to the disease stages, including LPG 18:1, serotonin, PC (22:4e/23:0), PC (19:2/18:5), hypoxanthin, PE (18:1/20:3), LPE 18:1, 1-stearoyl-2-arachidonoyl-sn-glycerol, and PE (16:0/18:1); with AONFH disease progresses from I/II stages to III/IV stages, the relative content of these 9 differential lipid metabolites was increased. In the SONFH group, 8 differential lipid metabolites were found to be related to the stage of the disease, including TM6076000, 4-(1,1-dimethylpropyl)phenol, D-617, asarone, phenylac-gln-OH, creatine, leu-pro, and 8-amino-7-oxononanoic acid; and with the SONFH progressed from stage I/II to stage III/IV, the content of these 8 differential lipid metabolites were gradually increased.

CONCLUSIONS

This study analyzes the characteristics of the plasma lipid metabolism profile in the AONFH and SONFH patients, and which identifies the differential lipid metabolites related to disease diagnosis and evaluation. These results provide evidence for exploring lipid metabolism alterations and the mining of novel lipid biomarkers for the ONFH.

TBX3 regulates the transcription of VEGFA to promote osteoblasts proliferation and microvascular regeneration

Objective

Osteochondral decellularization can promote local vascular regeneration, but the exact mechanism is unknown. The aim of this study is to study osteogenic microvascular regeneration in single cells.

Methods

The scRNA-seq dataset of human periosteal-derived cells (hPDCs) were analyzed by pySCENIC. To examine the role of TBX3 in osteogenesis and vascularization, cell transfection, qRT-PCR, western blot, and CCK-8 cell proliferation assays were performed.

Results

TCF7L2, TBX3, FLI1, NFKB2, and EZH2 were found to be transcription factors (TFs) most closely associated with corresponding cells. The regulatory network of these TFs was then visualized. Our study knocked down the expression of TBX3 in human osteoblast cell lines. In the TBX3 knockdown group, we observed decreased expression of VEGFA, VEGFB, and VEGFC. Moreover, Western blot analysis showed that downregulating TBX3 resulted in a reduction of VEGFA expression. And TBX3 stimulated osteoblast proliferation in CCK-8 assays.

Conclusion

TBX3 regulates VEGFA expression and promotes osteoblast proliferation in skeletal microvasculature formation. The findings provide a theoretical basis for investigating the role of TBX3 in promoting local vascular regeneration.

Regulation of osteoclast-mediated bone resorption by microRNA

Osteoclast-mediated bone resorption is responsible for bone metabolic diseases, negatively impacting people's health and life. It has been demonstrated that microRNA influences the differentiation of osteoclasts by regulating the signaling pathways during osteoclast-mediated bone resorption. So far, the involved mechanisms have not been fully elucidated. This review introduced the pathways involved in osteoclastogenesis and summarized the related microRNAs binding to their specific targets to mediate the downstream pathways in osteoclast-mediated bone resorption. We also discuss the clinical potential of targeting microRNAs to treat osteoclast-mediated bone resorption as well as the challenges of avoiding potential side effects and producing efficient delivery methods.

Pro-angiognetic and pro-osteogenic effects of human umbilical cord mesenchymal stem cell-derived exosomal miR-21-5p in osteonecrosis of the femoral head

Mesenchymal stem cell (MSC)-derived exosomes (Exos) enhanced new bone formation, coupled with positive effects on osteogenesis and angiogenesis. This study aims to define the role of microRNA (miR)-21-5p delivered by human umbilical MSC-derived Exos (hucMSC-Exos) in the osteonecrosis of the femoral head (ONFH). We first validated that miR-21-5p expression was downregulated in the cartilage tissues of ONFH patients. Besides, hucMSCs delivered miR-21-5p to hFOB1.19 cells and human umbilical vein endothelial cells (HUVECs) through the secreted Exos. Loss- and gain-of-function approaches were performed to clarify the effects of Exo-miR-21-5p, SOX5, and EZH2 on HUVEC angiogenesis and hFOB1.19 cell osteogenesis. It was established that Exo-miR-21-5p augments HUVEC angiogenesis and hFOB1.19 cell osteogenesis in vitro, as reflected by elevated alkaline phosphatase (ALP) activity and calcium deposition, and increased the expression of osteogenesis-related markers OCN, Runx2 and Collagen I. Mechanistically, miR-21-5p targeted SOX5 and negatively regulated its expression, while SOX5 subsequently promoted the transcription of EZH2. Ectopically expressed SOX5 or EZH2 could counterweigh the effect of Exo-miR-21-5p. Further, hucMSC-Exos containing miR-21-5p repressed the expression of SOX5 and EZH2 and augmented angiogenesis and osteogenesis in vivo. Altogether, our study uncovered the role of miR-21-5p shuttled by hucMSC-Exos, in promoting angiogenesis and osteogenesis, which may be a potential therapeutic target for ONFH.

SMAD4 transcriptionally activates GCN5 to inhibit apoptosis and promote osteogenic differentiation in dexamethasone-induced human bone marrow mesenchymal stem cells

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is a serious complication caused by long-term or excessive use of glucocorticoids (GCs). General control non-derepressible 5 (GCN5) has been reported to be lowly expressed in bone tissue. Therefore, this paper attempts to investigate the role of GCN5 in SONFH and identify the potential regulatory mechanism.

EXPERIMENTAL DESIGN

Following human bone mesenchymal stem cells (hBMSCs) being stimulated with dexamethasone (Dex), GCN5 expression was detected using RT-qPCR and western blotting. Then, GCN5 was overexpressed and cell viability was assessed by cell counting kit and lactate dehydrogenase kit. Cell apoptosis was determined with terminal deoxynucleotidyl transferase dUTPnickendlabeling (TUNEL) and the expression of apoptosis-related proteins was evaluated using western blotting. Alkaline phosphatase (ALP) staining and alizarin red staining were adopted for the analysis of osteogenic differentiation. Additionally, the relationship between small mothers against decapentaplegic protein 4 (SMAD4) and GCN5 was predicted by hTFtarget website and verified by luciferase reporter- and chromatin immunoprecipitation (ChIP) assays. Subsequently, SMAD4 was silenced to determine cell viability, apoptosis and osteogenic differentiation in Dex-induced hBMSCs with GCN5 upregulation.

RESULTS

GCN5 expressed lower in hBMSCs exposed to Dex. GCN5 overexpression elevated cell viability, attenuated apoptosis and promoted osteogenic differentiation of hBMSCs. Additionally, SMAD4 transcriptionally activated GCN5 and upregulated GCN5 expression. While SMAD4 knockdown reversed the protective effects of GCN5 overexpression on Dex-induced cell viability loss, apoptosis increase and osteogenic differentiation inhibition in hBMSCs.

CONCLUSIONS

SMAD4 transcriptionally activated GCN5 to inhibit apoptosis and promote osteogenic differentiation in Dex-induced hBMSCs.

Identification of Hub Genes and Pathways Associated with Oxidative Stress of Cartilage in Osteonecrosis of Femoral Head Using Bioinformatics Analysis

OBJECTIVE

This study aimed to identify the hub genes and pathways of genes related to oxidative stress of cartilage in osteonecrosis of femoral head (ONFH), and to predict the transcription factors of the hub genes.

METHODS

The GSE74089 was obtained from the Gene Expression Omnibus (GEO) database, including 4 necrotic tissues and 4 normal tissues, and the differentially expressed genes (DEGs) were identified by limma package in R language. Simultaneously, we searched for the genes related to oxidative stress in the Gene Ontology (GO) database. GO and signaling pathways analysis were performed using DAVID, Metascape, and GSEA. Protein-protein interaction (PPI) network was constructed using the STRING database, and the Degree algorithm of Cytoscape software was used to screen for hub genes. Finally, the NetworkAnalyst web tool was used to find the hub genes' transcriptional factors (TFs).

RESULTS

In total, 440 oxidative stress-related genes were found in GSE74089 and GO database, and 88 of them were significantly differentially expressed. These genes were mainly involved in several signaling pathways, such as MAPK signaling pathway, PI3K-AKT-mTOR signaling pathway, FOXO signaling pathway. The top 10 hub genes were JUN, FOXO3, CASP3, JAK2, RELA, EZH2, ABL1, PTGS2, FBXW7, MCL1. Besides, TFAP2A, GATA2, SP1, and E2F1 may be the key regulatory factors of hub genes.

CONCLUSIONS

We identified some hub genes and signaling pathways associated with oxidative stress in ONFH through a series of bioinformatics analyses.

Identification of key biomarkers in steroid-induced osteonecrosis of the femoral head and their correlation with immune infiltration by bioinformatics analysis

Objective

This study aimed to identify key diagnostic markers and immune infiltration of (SONFH) by bioinformatics analysis.

Methods

Related SONFH datasets were downloaded from the Gene Expression Omnibus (GEO) database. First, we identified the differentially expressed genes (DEGs) and performed the functional enrichment analysis. Then weighted correlation network analysis (WGCNA) and the MCODE plug-in in Cytoscape were used to identify the diagnostic markers of SONFH. Finally, CIBERSORT was used to analyze the immune infiltration between SONFH and healthy controls, and the correlation between infiltrating immune cells and diagnostic markers was analyzed.

Results

TYROBP, TLR2, P2RY13, TLR8, HCK, MNDA, and NCF2 may be key diagnostic markers of SONFH. Immune cell infiltration analysis revealed that Memory B cells and activated dendritic cells may be related to the SONFH process. Moreover, HCK was negatively correlated with CD8 T cells, and neutrophils were positively correlated with those key diagnostic markers.

Conclusions

TYROBP, TLR2, P2RY13, TLR8, HCK, MNDA, and NCF2 may be used as diagnostic markers of SONFH, and immune-related mechanism of SONFH and the potential immunotherapy are worthy of further study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-04994-7.

Integrated Analysis of miRNA-mRNA Regulatory Networks Associated with Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) accounts for as many as 18% of total hip arthroplasties. Knowledge of genetic changes and molecular abnormalities could help identify individuals considered to be at a higher risk of developing ONFH. In this study, we sought to identify differentially expressed miRNAs (DEmiRs) and genes (DEGs) associated with ONFH by integrated bioinformatics analyses as well as to construct the miRNA-mRNA regulatory network involving in the pathogenesis of ONFH. We performed differential expression analysis using a gene expression profile GSE123568 and a miRNA expression profile GSE89587 deposited in the Gene Expression Omnibus and identified 47 DEmiRs (24 upregulated miRNAs and 23 downregulated miRNAs) and 529 DEGs (218 upregulated genes and 311 downregulated genes). Gene Ontology enrichment analyses of DEGs suggested that DEGs were significantly enriched in neutrophil activation, cytosol, and ubiquitin-protein transferase activity. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of DEGs revealed that DEGs were significantly enriched in transcriptional misregulation in cancer. DEGs-based miRNA-mRNA regulatory networks were obtained by searching miRNA-mRNA prediction databases, TargetScan, miTarBase, miRMap, miRDB, and miRanda databases. Then, overlapped miRNAs were selected between these putative miRNAs and DEmiRs between ONFH and non-ONFH, and pairs of the DEmiR-DEG regulatory network were finally depicted. There were 12 nodes and 64 interactions for upDEmiR-downDEG regulatory networks and 6 nodes and 16 interactions for downDEmiR-upDEG regulatory networks. Using the STRING database, we established a protein-protein interaction network based on the overlapped DEGs between ONFH and non-ONFH. C5AR1, CDC27, CDC34, KAT2B, CPPED1, TFDP1, and MX2 were identified as the hub genes. The present study characterizes the miRNA profile, gene profile, and miRNA-mRNA regulatory network in ONFH, which may contribute to the interpretation of the pathogenesis of ONFH and the identification of novel biomarkers and therapeutic targets for ONFH.

The role of biomechanical forces and MALAT1/miR-329-5p/PRIP signalling on glucocorticoid-induced osteonecrosis of the femoral head

Glucocorticoid‐induced osteonecrosis of the femoral head (GIONFH) is a common orthopaedic disease. GIONFH primarily manifests clinically as hip pain in the early stages, followed by the collapse of the femoral head, narrowing of the hip joint space and damage to the acetabulum, resulting in severely impaired mobility. However, the pathogenesis of GIONFH is not clearly understood. Recently, biomechanical forces and non‐coding RNAs have been suggested to play important roles in the pathogenesis of GIONFH. This study aimed to evaluate the role of biomechanical forced and non‐coding RNAs in GIONFH. We utilized an in vivo, rat model of GIONFH and used MRI, μCT, GIONFH‐TST (tail suspension test), GIONFH‐treadmill, haematoxylin and eosin staining, qRT‐PCR and Western blot analysis to analyse the roles of biomechanical forces and non‐coding RNAs in GIONFH. We used RAW264.7 cells and MC3T3E1 cells to verify the role of MALAT1/miR‐329‐5p/PRIP signalling using a dual luciferase reporter assay, qRT‐PCR and Western blot analysis. The results demonstrated that MALAT1 and PRIP were up‐regulated in the femoral head tissues of GIONFH rats, RAW264.7 cells, and MC3T3E1 cells exposed to dexamethasone (Dex). Knockdown of MALAT1 decreased PRIP expression in rats and cultured cells and rescued glucocorticoid‐induced osteonecrosis of femoral head in rats. The dual luciferase reporter gene assay revealed a targeting relationship for MALAT1/miR‐329‐5p and miR‐329‐5p/PRIP in MC3T3E1 and RAW264.7 cells. In conclusion, MALAT1 played a vital role in the pathogenesis of GIONFH by binding to (‘sponging’) miR‐329‐5p to up‐regulate PRIP. Also, biomechanical forces aggravated the pathogenesis of GIONFH through MALAT1/miR‐329‐5p/PRIP signalling.

Mechanism of dexmedetomidine regulating osteogenesis-angiogenesis coupling through the miR-361-5p/VEGFA axis in postmenopausal osteoporosis

AIMS

Postmenopausal osteoporosis (PMOP) is a growing health problem affecting many postmenopausal women. This study intended to identify the role of dexmedetomidine (Dex) in osteoporosis (OP).

MAIN METHODS

Microarray analysis was performed for the gene expression profiles of PMOP patients and postmenopausal healthy volunteers, and the most differentially expressed microRNA (miR)-361-5p was verified in clinic, and its diagnostic value in PMOP patients was analyzed. After establishment of OP model by ovariectomy, Dex treatment and overexpression of miR-361-5p or vascular endothelial growth factor A (VEGFA) were performed in OP rats or isolated bone marrow mesenchymal stem cells (BMSCs). Bone mineral density (BMD) related indexes and levels of osteogenesis-angiogenesis related genes were measured. The apoptosis and osteogenic differentiation of BMSCs were detected. After human umbilical vein endothelial cells (HUVECs) and BMSCs were cocultured, the angiogenesis of BMSCs was detected by Matrigel-based angiogenesis experiment.

KEY FINDINGS

miR-361-5p was highly expressed in PMOP patients and OP rats, with good diagnostic effect on PMOP. After Dex treatment, the expressions of miR-361-5p, VEGFA, BMD related indexes were increased in OP rats. In BMSCs, level of osteogenesis-angiogenesis related genes were increased after adding Dex, and the apoptosis was decreased after coculture of HUVECs and BMSCs. miR-361-5p could target VEGFA. After miR-361-5p overexpression + Dex treatment, the indexes related to osteogenesis and angiogenesis in OP rats and BMSCs were decreased, which were reversed after further overexpressing VEGFA.

SIGNIFICANCE

Dex can enhance VEGFA by inhibiting miR-361-5p, and then promote osteogenesis-angiogenesis, thus providing potential targets for PMOP treatment.

The role of hypoxia in the tumor microenvironment and development of cancer stem cell: a novel approach to developing treatment

Hypoxia is a common feature of solid tumors, and develops because of the rapid growth of the tumor that outstrips the oxygen supply, and impaired blood flow due to the formation of abnormal blood vessels supplying the tumor. It has been reported that tumor hypoxia can: activate angiogenesis, thereby enhancing invasiveness and risk of metastasis; increase survival of tumor, as well as suppress anti-tumor immunity and hamper the therapeutic response. Hypoxia mediates these effects by several potential mechanisms: altering gene expression, the activation of oncogenes, inactivation of suppressor genes, reducing genomic stability and clonal selection. We have reviewed the effects of hypoxia on tumor biology and the possible strategiesto manage the hypoxic tumor microenvironment (TME), highlighting the potential use of cancer stem cells in tumor treatment.

Silencing long noncoding RNA colon cancer-associated transcript-1 upregulates microRNA-34a-5p to promote proliferation and differentiation of osteoblasts in osteoporosis

Long noncoding RNAs (lncRNAs) have been revealed to be related to multiple physiological and pathology processes such as development, carcinogenesis, and osteogenesis. It is reported that lncRNAs might exert function in osteoblast differentiation and bone formation. Here, we determined this study to clarify whether lncRNA CCAT1 could regulate osteoblast proliferation and differentiation in ovariectomized rats with osteoporosis. The osteoporosis models were established by bilateral ovariectomy and treated with CCAT1 siRNAs to discuss the effect of CCAT1 on pathological changes and osteocyte apoptosis in ovariectomized rats with osteoporosis. The osteoblasts from ovariectomized rats were cultured in vitro, which were then treated with CCAT1 siRNAs to explore the role of CCAT1 in osteoblast proliferation and differentiation. Moreover, the relationships among CCAT1, miR-34a-5p, and SMURF2 were confirmed. CCAT1 and SMURF2 were amplified while miR-34a-5p expression was inhibited in bone tissues and osteoblasts of ovariectomized rats with osteoporosis. Inhibited CCAT1 improved pathology and restricted osteocyte apoptosis of bone tissues in ovariectomized rats with osteoporosis in vivo, and also enhanced differentiation, mineralization abilities, and proliferation, and suppressed apoptosis of osteoblasts from ovariectomized rats in vitro through upregulating miR-34a-5p expression. LncRNA CCAT1 could competitively bind with miR-34a-5p to prevent the degradation of its target gene SMURF2. Results of this research suggested that the CCAT1 inhibits the proliferation and differentiation of osteoblasts in rats with osteoporosis by binding to miR-34a-5p, providing novel biomarkers for osteoporosis treatment.

MicroRNAs are critical regulators of senescence and aging in mesenchymal stem cells

MicroRNAs (miRNAs) have recently come under scrutiny for their role in various age-related diseases. Similarly, cellular senescence has been linked to disease and aging. MicroRNAs and senescence likely play an intertwined role in driving these pathologic states. In this review, we present the connection between these two drivers of age-related disease concerning mesenchymal stem cells (MSCs). First, we summarize key miRNAs that are differentially expressed in MSCs and other musculoskeletal lineage cells during senescence and aging. Additionally, we also reviewed miRNAs that are regulated via traditional senescence-associated secretory phenotype (SASP) cytokines in MSC. Lastly, we summarize miRNAs that have been found to target components of the cell cycle arrest pathways inherently activated in senescence. This review attempts to highlight potential miRNA targets for regenerative medicine applications in age-related musculoskeletal disease.

MiR-23b-3p promotes postmenopausal osteoporosis by targeting MRC2 and regulating the Wnt/β-catenin signaling pathway

Postmenopausal osteoporosis (PMOP) is one of the most common metabolic bone diseases in postmenopausal women. Increasing evidence has indicated that microRNAs (miRNAs) play vital regulatory roles during osteoporosis progression. This study aimed to investigate the potential function of miR-23b-3p in the osteogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs). PMOP was induced in mice by bilateral ovariectomy. X-ray absorptiometry was applied to detect BMD and BMC in PMOP mice. Luciferase reporter assay and RIP assay were utilized to investigate the relationship between miR-23b-3p and MRC2. We found the upregulation of miR-23b-3p in bone tissues of PMOP mice. Silencing of miR-23b-3p relieved PMOP in mice. Moreover, miR-23b-3p knockdown facilitated the osteogenic differentiation of hMSCs by increasing the expression of Runx2, OCN, Osterix and promoting ALP activity. Mechanistically, MRC2 is a downstream target gene of miR-23b-3p. MRC2 knockdown significantly rescued the promoting effect of lenti-miR-23b-3p inhibitor on osteogenic differentiation of hMSCs. Furthermore, miR-23b-3p targeted MRC2 to inhibit the Wnt/β-catenin pathway during the osteogenic differentiation of hMSCs. In summary, inhibition of miR-23b-3p alleviates PMOP by targeting MRC2 to inhibit the Wnt/β-catenin signaling, which may provide a novel molecular insight for osteoporosis therapy.

MicroRNA-23b-3p participates in steroid-induced osteonecrosis of the femoral head by suppressing ZNF667 expression

BACKGROUND

Clinical treatment with high-dose of steroid hormone causes steroid-induced osteonecrosis of the femoral head (SONFH), whereas the internal regulation mechanism remains elusive. Numerous studies have reported that microRNAs participated in the development of SONFH through modulating gene expression. The aim of the current study was to clarify the function of microRNA-23b-3p (miR-23b-3p) and ZNF667 in SONFH.

EXPERIMENTAL DESIGN

Bioinformatics prediction and luciferase reporter system were utilized to confirm the target relation between miR-23b-3p and ZNF667. To examine the function of miR-23b-3p in vivo, rat SONFH models were established by specific inducers. The morphological changes, plasma viscosity, blood lipid, and inflammatory cytokines were measure by corresponding experiments.

RESULTS

MiR-23b-3p and ZNF667 was negatively correlated in SONFH patient tissues, miR-23b-3p was down-regulated, while ZNF667 was up-regulated. MiR-23b-3p targeted ZNF667, the expression level of ZNF667 was suppressed by miR-23b-3p activation whereas strengthened by miR-23b-3p inhibition. SONHF rats with overexpressed miR-23b-3p displayed alleviated symptoms, including reduced plasma viscosity, declined blood lipids, decreased levels of pro-inflammatory cytokines and improved bone integrality. Moreover, elevation of ZNF667 reversed the repression of SONFH induced by miR-23b-3p overexpression.

CONCLUSIONS

We found that miR-23b-3p played a protective role in SONFH by targeting ZNF667, which provided a novel reference for SONFH prevention and therapy.

The pathogenesis, diagnosis and clinical manifestations of steroid-induced osteonecrosis

Corticosteroid associated osteonecrosis is bone death resulting from the use of chronic glucocorticoids and most commonly affects the femoral head, although the bones such as around knee joint, wrist joint and ankle joint can be affected. The pathogenesis is likely multifactorial, with genetic and environmental factors playing a role. Epigenetics may be the mechanism by which environment exerts it effects. In spite of recent discoveries, the exact pathogenesis of corticosteroid associated osteonecrosis is unknown. Over the past few years, more miRNA's have been found to be associated with osteonecrosis. The older mechanisms such as a coagulopathy, abnormalities in apoptosis and lipid metabolism dysfunction are still believed to play a role. The role of inflammatory pathways including the PDK1/AKT/mTOR signaling pathway, the PERK and Parkin pathways have been increasingly recognized as playing a mechanistic role. Histological damage to the joint can occur before the presence of symptoms. The most common symptoms are pain and an inability to bear weight. Differential diagnosis includes infection, bone marrow edema syndrome or subchondral fracture. Early detection is important for successful management of the condition. MRI is the best radiologic technique to diagnosis femoral head osteonecrosis. Multiple staging systems for osteonecrosis have been used over the years, including the Ficat and Arlet system and the Steinberg criteria. The later stages of these staging systems are irreversible. Both non-surgical (conservative) and surgical modes of therapy are used in the treatment of osteonecrosis.