miR-532-3p inhibits osteogenic differentiation in MC3T3-E1 cells by downregulating ETS1

Static magnetic field contributes to osteogenic differentiation of hPDLSCs through the H19/Wnt/β-catenin axis

BACKGROUND

Static magnetic field (SMF) as an effective physical stimulus is capable of osteogenic differentiation for multiple mesenchymal stem cells, including human periodontal ligament stem cells (hPDLSCs). However, the exact molecular mechanism is still unknown. Therefore, this study intends to excavate molecular mechanisms related to SMF in hPDLSCs using functional experiments.

METHODS

hPDLSCs were treated with different intensities of SMF, H19 lentivirus, and Wnt/β-catenin pathway inhibitor (XAV939). Changes in osteogenic markers (Runx2, Col Ⅰ, and BMP2), Wnt/β-catenin markers (β-catenin and GSK-3β), and calcified nodules were examined using RT-qPCR, western blotting, and alizarin red staining in hPDLSCs.

RESULTS

SMF upregulated the expression of H19, and SMF and overexpressing H19 facilitated the expression of osteogenic markers (Runx2, Col Ⅰ, and BMP2), activation of the Wnt/β-catenin pathway, and mineralized sediment in hPDLSCs. Knockdown of H19 alleviated SMF function, and treatment with XAV939 limited SMF- and H19-mediated osteogenic differentiation of hPDLSCs. Notably, the expression of hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p in hPDLSCs was regulated by SMF, and may form an endogenous competitive RNA mechanism with H19 and β-catenin.

CONCLUSION

SMF contributes to the osteogenic differentiation of hPDLSCs by mediating the H19/Wnt/β-catenin pathway, and hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p may be the key factors in it.

Stiff extracellular matrix drives the differentiation of mesenchymal stem cells toward osteogenesis by the multiscale 3D genome reorganization

Extracellular matrix (ECM) stiffness is a major driver of stem cell fate. However, the involvement of the three-dimensional (3D) genomic reorganization in response to ECM stiffness remains unclear. Here, we generated comprehensive 3D chromatin landscapes of mesenchymal stem cells (MSCs) exposed to various ECM stiffness. We found that there were more long-range chromatin interactions, but less compartment A in MSCs cultured on stiff ECM than those cultured on soft ECM. However, the switch from compartment B in MSCs cultured on soft ECM to compartment A in MSCs cultured on stiff ECM included genes encoding proteins primarily enriched in cytoskeleton organization. At the topologically associating domains (TADs) level, stiff ECM tends to have merged TADs on soft ECM. These merged TADs on stiff ECM include upregulated genes encoding proteins enriched in osteogenesis, such as SP1, ETS1, and DCHS1, which were validated by quantitative real-time polymerase chain reaction and found to be consistent with the increase of alkaline phosphatase staining. Knockdown of SP1 or ETS1 led to the downregulation of osteogenic marker genes, including COL1A1, RUNX2, ALP, and OCN in MSCs cultured on stiff ECM. Our study provides an important insight into the stiff ECM-mediated promotion of MSC differentiation towards osteogenesis, emphasizing the influence of mechanical cues on the reorganization of 3D genome architecture and stem cell fate.

Isolation and characterization of bone mesenchymal cell small extracellular vesicles using a novel mouse model

Extracellular vesicles (EVs) are key mediators of cell-cell communication and are involved in transferring specific biomolecular cargo to recipient cells to regulate their physiological functions. A major challenge in the understanding of EV function in vivo is the difficulty ascertaining the origin of the EV particles. The recent development of the "Snorkel-tag," which includes EV-membrane-targeted CD81 fused to a series of extra-vesicular protein tags, can be used to mark EVs originating from a specific source for subsequent isolation and characterization. We developed an in vivo mouse model, termed "CAGS-Snorkel," which expresses the Snorkel-tag under the control of the Cre-lox system, and crossed this mouse with either Prx1-Cre (mesenchymal progenitors) or Ocn-Cre (osteoblasts/osteocytes) and isolated Snorkel-tagged EVs from the mouse bone marrow plasma using a magnetic bead affinity column. miRNA-sequencing was performed on the isolated EVs, and although similar profiles were observed, a few key miRNAs involved in bone metabolism (miR-106b-5p, miRs-19b-3p, and miRs-219a-5p) were enriched in the Ocn-derived relative to the Prx1-derived EV subpopulations. To characterize the effects of these small EVs on a bone cell target, cultured mouse bone marrow stromal cells were treated with Prx1 or Ocn EVs, and mRNA-sequencing was performed. Pathways involved in ossification, bone development, and extracellular matrix interactions were regulated by both EV subpopulations, whereas a few pathways including advanced glycation end-products signaling were uniquely regulated in the Ocn EV subpopulation, underlying important biological effects of specific EV subpopulations within the bone marrow microenvironment. These data demonstrate that EV isolation in vivo using the CAGS-Snorkel mouse model is a useful tool in characterizing the cargo and understanding the biology of tissue-specific EVs. Moreover, while bone mesenchymal cell populations share a common EV secretory profile, we uncover key differences based on the stage of osteoblastic differentiation that may have important biological consequences.

LncRNA NEAT1 Inhibits Neuronal Apoptosis and Induces Neuronal Viability of Depressed Rats Via microRNA-320-3p/CRHR1 Axis

Long noncoding RNA nuclear enriched abundant transcript 1 (NEAT1) has been reported to be involved in depression. This study aims to investigate the mechanism of NEAT1/microRNA (miR)-320-3p/Corticotropin-releasing hormone receptor 1 (CRHR1) axis in depressed rats. Rats with depression-like behaviors were prepared by exposing the rats to chronic unpredictable mild stress. Behavioral functions, pathological damage, neuronal apoptosis and monoamine neurotransmitter were examined in depressed rats . Primary hippocampal neurons were injured through simulation with corticosterone(CORT). Cell viability and apoptosis were measured in CORT-Induced hippocampal neurons. The binding relationship between NEAT1 and miR-320-3p and the targeting relationship between miR-320-3p and CRHR1 were detected. Elevated NEAT1, CRHR1 and reduced miR-320-3p exhibited in depressed rats and CORT-treated hippocampal neurons, NEAT1 bound to miR-320-3p to target CRHR1. Silencing NEAT1 or elevating miR-320-3p improved behavioral functions, attenuated pathological damage and apoptosis in the hippocampus, and increased monoamine neurotransmitter in depressed rats. Repression of NEAT1 or promotion of miR-320-3p enhanced viability and suppressed apoptosis of CORT-treated hippocampal neurons. The study highlights that NEAT1 competitively binds to miR-320-3p to up-regulate CRHR1 expression, thereby promoting hippocampal damage of depressed rats.

MicroRNA-877-5p promotes osteoblast differentiation by targeting EIF4G2 expression

Stimulating bone formation potentially suggests therapeutics for orthopedic diseases including osteoporosis and osteoarthritis. Osteoblasts are key to bone remodeling because they act as the only bone-forming cells. miR-877-5p has a chondrocyte-improving function in osteoarthritis, but its effect on osteoblast differentiation is unknown. Here, miR-877-5p-mediated osteoblast differentiation was studied. Real-time reverse transcriptase-polymerase chain reaction was performed to measure miR-877-5p expression during the osteogenic differentiation of MC3T3-E1 cells. Osteoblast markers, including alkaline phosphatase (ALP), collagen type I a1 chain, and osteopontin, were measured and detected by alizarin red staining and ALP staining. Potential targets of miR-877-5p were predicted from three different algorithms: starBase ( http://starbase.sysu.edu.cn/ ), PITA ( http://genie.weizmann.ac.il/pubs/mir07/mir07_data.html ), and miRanda ( http://www.microrna.org/microrna/home.do ). It was further verified by dual luciferase reporter gene assay. The experimental results found that miR-877-5p was upregulated during the osteogenic differentiation of MC3T3-E1 cells. Overexpression of miR-877-5p promoted osteogenic differentiation, which was characterized by increased cell mineralization, ALP activity, and osteogenesis-related gene expression. Knockdown of miR-877-5p produced the opposite result. Dual luciferase reporter gene assay showed that miR-877-5p directly targeted eukaryotic translation initiation factor 4γ2 (EIF4G2). Overexpression of EIF4G2 inhibited osteogenic differentiation and reversed the promoting effect of overexpression of miR-135-5p on osteogenic differentiation. These results indicate that miR-877-5p might have a therapeutic application related to its promotion of bone formation through targeting EIF4G2.

LncRNA USP2-AS1 facilitates the osteogenic differentiation of bone marrow mesenchymal stem cells by targeting KDM3A/ETS1/USP2 to activate the Wnt/β-catenin signaling pathway

Human bone marrow mesenchymal stem cells (HBMSCs) can promote new bone formation. Previous studies have proven the ability of long non-coding RNAs (lncRNAs) to modulate the osteogenic differentiation of mesenchymal stem cells. However, the molecular mechanism modulated by lncRNAs in affecting the osteogenic differentiation of HBMSCs remains largely unknown. Thus, this study aims to reveal the role of lncRNA ubiquitin-specific peptidase 2 antisense RNA 1 (USP2-AS1) in regulating the osteogenic differentiation of HBMSCs and investigate its regulatory mechanism. Through bioinformatics analysis and RT-qPCR, we confirmed that USP2-AS1 expression was increased in HBMSCs after culturing in osteogenic differentiation medium (OM-HBMSCs). Moreover, we uncovered that knockdown of USP2-AS1 inhibited the osteogenic differentiation of HBMSCs. Further exploration indicated that USP2-AS1 positively regulated the expression of its nearby gene USP2. Mechanistically, USP2-AS1 recruited lysine demethylase 3A (KDM3A) to stabilize ETS proto-oncogene 1 (ETS1), transcription factor that transcriptionally activated USP2. Additionally, USP2-induced Wnt/β-catenin signalling pathway activation via deubiquitination of β-catenin protein. In summary, our study proved that lncRNA USP2-AS1 facilitates the osteogenic differentiation of HBMSCs by targeting KDM3A/ETS1/USP2 axis to activate the Wnt/β-catenin signalling pathway.

Icariin promotes the proliferation and osteogenic differentiation of bone-derived mesenchymal stem cells in patients with osteoporosis and T2DM by upregulating GLI-1

BACKGROUND

The function of mesenchymal stem cells (MSCs) from patients with osteoporosis (OP) is impaired and worsens in patients with type 2 diabetes mellitus (T2DM). Icariin (ICA) is the major active flavonoid glucoside isolated from traditional Chinese herbal Epimedium pubescens, and confirmed able to improve bone mass of OP patients.

OBJECTIVE

To investigate the effect of ICA on the proliferation and osteogenic differentiation of bone-derived MSCs (BMSCs) from patients with OP and T2DM and uncover the potential mechanism.

METHODS

BMSCs were treated with ICA, and proliferation and osteogenic potency were evaluated using the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and detection of osteogenic markers (ALP, RUNX2, SPP1, COL1A1, and mineralized nodules) was performed. RNA sequencing and bioinformatic analysis were performed to identify differentially expressed genes (DEGs) after ICA treatment and screen proliferation- and osteogenic differentiation-related processes. Gene gain and loss were performed to confirm the role of the key candidate gene.

RESULTS

ICA significantly promoted the proliferation and osteogenic differentiation of BMSCs. A total of 173 DEGs were identified after ICA treatment. Six DEGs (GLI-1, IGF2, BMP6, WNT5A, PTHLH, and MAPK14) enriched in both proliferation- and osteogenic differentiation-related processes were screened; GLI-1 had the highest validated |log2FC| value. Overexpression of GLI-1 enhanced the proliferation and osteogenic differentiation of BMSCs, and knockdown of GLI-1 weakened the positive effect of ICA on BMSCs.

CONCLUSION

ICA promoted the proliferation and osteogenic differentiation of impaired BMSCs by upregulating GLI-1.

LncRNA HOTAIRM1 promotes osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting miR-152-3p/ETS1 axis

BACKGROUND

Bone marrow mesenchymal stem cells (BMSCs) can differentiate into osteoblasts and thus present a tremendous therapeutic potential in osteoporosis. Here, we elucidated the involvement of long non-coding RNAs (lncRNAs) HOXA transcript antisense RNA, myeloid-specific 1 (HOTAIRM1) in the osteogenic differentiation of BMSCs.

METHODS AND RESULTS

The expression levels of HOTAIRM1, miR-152-3p, ETS proto-oncogene 1 (ETS1), runt-related transcription factor 2 (RUNX2), Osterix, and osteocalcin (OCN) were determined by a quantitative real-time polymerase chain reaction (qRT-PCR) or western blot method. Targeted relationship between miR-152-3p and HOTAIRM1 or ETS1 was confirmed by dual-luciferase reporter and RNA pull-down assays. The activity of alkaline phosphatase (ALP) was measured by the ALP Activity Assay Kit. The extent of the calcium deposition was assessed by Alizarin Red Staining. Our data showed that HOTAIRM1 and ETS1 levels were up-regulated and miR-152-3p expression was down-regulated during osteogenic differentiation of human BMSCs (HBMSCs). HOTAIRM1 overexpression enhanced osteogenic differentiation of HBMSCs, and decreased level of HOTAIRM1 suppressed osteogenic differentiation of HBMSCs. HOTAIRM1 directly targeted miR-152-3p. ETS1 was identified as a direct and functional target of miR-152-3p. Furthermore, HOTAIRM1 functioned as a post-transcriptional regulator of ETS1 expression by miR-152-3p.

CONCLUSION

The findings in this paper identify HOTAIRM1 as a novel regulator of osteogenic differentiation of BMSCs by the regulation of miR-152-3p/ETS1 axis, uncovering HOTAIRM1 as a promising therapeutic strategy for osteoporosis.

Abnormal expression pattern of lncRNA H19 participates in multiple myeloma bone disease by unbalancing osteogenesis and osteolysis

BACKGROUND

Accumulating genetic and epigenetic alterations in multiple myeloma (MM) have been demonstrated to be closely associated with osteolytic bone disease, generally characterized as increased osteoclast formation and decreased osteoblast activity. Previously, serum long non-coding RNA (lncRNA) H19 has been proved to be a biomarker for the diagnosis of MM. Whereas, its role in MM-associated bone homeostasis remains largely elusive.

METHODS

A cohort of 42 MM patients and 40 healthy volunteers were enrolled for evaluating differential expressions of H19 and its downstream effectors. The proliferative capacity of MM cells was monitored by CCK-8 assay. Alkaline phosphatase (ALP) staining and activity detection, either with Alizarin red staining (ARS) were employed to assess osteoblast formation. Osteoblast- or osteoclast-associated gene were detected using qRT-PCR and western blot analysis. Bioinformatics analysis, RNA pull-down, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) were subjected to verify H19/miR-532-3p/E2F7/EZH2 axis, which was accounted for epigenetic suppression of PTEN. The functional role of H19 on MM development through unbalancing osteolysis and osteogenesis was also confirmed in the murine MM model.

RESULTS

Upregulation of serum H19 was observed in MM patients, suggesting its positive correlation with the poor prognosis of MM patients. Loss of H19 dramatically weakened cell proliferation of MM cells, promoted osteoblastic differentiation, and impaired osteoclast activity. While reinforced H19 exhibited the opposite effects. Akt/mTOR signaling plays an indispensable role in H19-mediated osteoblast formation and osteoclastgenesis. Mechanistically, H19 served as a sponge for miR-532-3p to upregulate E2F7, a transcriptional activator of EZH2, thereby accounting for modulating epigenetic suppression of PTEN. The in vivo experiments further validated that H19 exerted important impacts on tumor growth through breaking the balance between osteogenesis and osteolysis via Akt/mTOR signaling.

CONCLUSION

Collectively, increased enrichment of H19 in MM cells exhibits an essential role in MM development by disturbing bone homeostasis.

Comprehensive ceRNA network for MACF1 regulates osteoblast proliferation

BACKGROUND

Previous studies have shown that microtubule actin crosslinking factor 1 (MACF1) can regulate osteoblast proliferation and differentiation through non-coding RNA (ncRNA) in bone-forming osteoblasts. However, the role of MACF1 in targeting the competing endogenous RNA (ceRNA) network to regulate osteoblast differentiation remains poorly understood. Here, we profiled messenger RNA (mRNA), microRNA (miRNA), and long ncRNA (lncRNA) expression in MACF1 knockdown MC3TC‑E1 pre‑osteoblast cells.

RESULTS

In total, 547 lncRNAs, 107 miRNAs, and 376 mRNAs were differentially expressed. Significantly altered lncRNAs, miRNAs, and mRNAs were primarily found on chromosome 2. A lncRNA-miRNA-mRNA network was constructed using a bioinformatics computational approach. The network indicated that mir-7063 and mir-7646 were the most potent ncRNA regulators and mef2c was the most potent target gene. Pathway enrichment analysis showed that the fluid shear stress and atherosclerosis, p53 signaling, and focal adhesion pathways were highly enriched and contributed to osteoblast proliferation. Importantly, the fluid shear stress and atherosclerosis pathway was co-regulated by lncRNAs and miRNAs. In this pathway, Dusp1 was regulated by AK079370, while Arhgef2 was regulated by mir-5101. Furthermore, Map3k5 was regulated by AK154638 and mir-466q simultaneously. AK003142 and mir-3082-5p as well as Ak141402 and mir-446 m-3p were identified as interacting pairs that regulate target genes.

CONCLUSION

This study revealed the global expression profile of ceRNAs involved in the differentiation of MC3TC‑E1 osteoblasts induced by MACF1 deletion. These results indicate that loss of MACF1 activates a comprehensive ceRNA network to regulate osteoblast proliferation.

Diet X Gene Interactions Control Femoral Bone Adaptation to Low Dietary Calcium

Genetics and dietary calcium (Ca) are each critical regulators of peak bone mass but it is unclear how genetics alters the physiologic response of bone to dietary Ca restriction (RCR). Here, we conducted genetic mapping in C57BL/6J × DBA/2J (BXD) recombinant inbred mouse lines to identify environmentally sensitive loci controlling whole-bone mass (bone mineral density [BMD], bone mineral content [BMC]), distal trabecular bone, and cortical bone midshaft of the femur. Mice were fed adequate (basal) or low Ca diets from 4-12 weeks of age. Femurs were then examined by dual-energy X-ray absorptiometry (DXA) and micro-computed tomography (μCT). Body size-corrected residuals were used for statistical analysis, genetic mapping, and to estimate narrow sense heritability (h2). Genetics had a strong impact on femoral traits (eg, bone volume fraction [BV/TV] basal Ca, h2 = 0.60) as well as their RCR (eg, BV/TV, h2 = 0.32). Quantitative trait locus (QTL) mapping identified up to six loci affecting each bone trait. A subset of loci was detected in both diet groups, providing replication of environmentally robust genetic effects. Several loci control multiple bone phenotypes suggesting the existence of genetic pleiotropy. QTL controlling the bone RCR did not overlap with basal diet QTL, demonstrating genetic independence of those traits. Candidate genes underlying select multi-trait loci were prioritized by protein coding effects or gene expression differences in bone cells. These include candidate alleles in Rictor (chromosome [chr] 15) and Egfl7 (chr 2) at loci affecting bone in the basal or low Ca groups and in Msr1 (chr 8), Apc, and Camk4 (chr 18) at loci affecting RCR. By carefully controlling dietary Ca and measuring traits in age-matched mice we identified novel genetic loci determining bone mass/microarchitecture of the distal femur as well as their physiologic adaptation to inadequate dietary Ca intake. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

miR-215-5p regulates osteoporosis development and osteogenic differentiation by targeting XIAP

Background

Osteoporosis (OP) is a metabolic disease that involves microstructure destruction and fracture damage. The present study probed into the significance of miR-215-5p in OP progression.

Methods

Serum samples were collected from surgical patients and healthy controls. qRT-PCR analysis was utilized to determine the miR-215-5p level in clinical samples and human bone mesenchymal stem cells (hBMSCs) induced by β-glycerol phosphate. A dual luciferase reporter assay was exploited to examine the targeted relationship between miR-215-5p and XIAP. The mineralization and calcium deposition of hBMSCs were assessed by detection of ALP activity, Alizarin red staining, and osteoblast marker expression. Protein expression was determined by western blot analysis.

Results

MiR-215-5p was significantly reduced in patients with OP and increased in hBMSCs treated with β-glycerophosphate. Enhanced miR-215-5p level triggered augment in osteoblast markers (Alkaline phosphatase/ ALP, Osteocalcin/ OCN, and Runt-Related Transcription Factor 2/ Runx2), which was accompanied by the increase of ALP activity in hBMSCs and accumulation of Calcium. Functional experiments show that XIAP was a target of miR-215-5p and negatively modulated by miR-215-5p. XIAP expression levels were increased in OP samples, and decreased XIAP in β-glycerophosphate-treated hBMSCs inhibited its’ osteogenic differentiation. Functional loss and acquisition experiments depicted that miR-215-5p promoted the differentiation of hBMSCs by inhibiting the XIAP level, playing a protective role in the pathogenesis of OP.

Conclusions

β-glycerophosphate promoted the osteogenic differentiation of hBMSCs, increased miR-215-5p level, and decreased XIAP. miR-215-5p stimulated osteogenic differentiation of hBMSCs by targeting XIAP, shedding new insights for the detection and therapy of OP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05731-w.

Melatonin Inhibits OGD/R-Induced H9c2 Cardiomyocyte Pyroptosis via Regulation of MT2/miR-155/FOXO3a/ARC Axis

Emerging literature suggests that pyroptosis plays a critical role in ischemia/hypoxia (I/R) -induced myocardial injury. Melatonin has been implicated in attenuating I/R-induced injury of cardiomyocytes. Nevertheless, whether melatonin inhibits I/R-induced pyroptosis of cardiomyocytes and the underlying molecular mechanisms remain unexploited.H9c2 cardiomyocytes were cultured under oxygen-glucose deprivation/reperfusion (OGD/R) condition to establish a myocardial pyroptosis model in vitro. OGD/R-induced pyroptosis was evaluated by CCK-8 assay, IL-1β and IL-18 release, and western blotting. Luciferase reporter assay was utilized to validate the association between miR-155 and Forkhead box O3a (FOXO3a).Melatonin could inhibit OGD/R-induced pyroptosis of H9c2 cells and upregulation of FOXO3a contributed to the antipyroptotic effect of melatonin. Melatonin reduced miR-155 expression, which led to FOXO3a upregulation and inhibition of pyroptosis in OGD/R-exposed H9c2 cells. miR-155 inhibitor enhanced the antipyroptotic effect of melatonin in OGD/R-exposed H9c2 cells. Melatonin-induced downregulation of miR-155 and upregulation of FOXO3a were reversed by melatonin receptor 2 (MT2) siRNA. Melatonin treatment also led to an increased level of apoptosis repressor with caspase recruitment domain (ARC), which was inhibited by FOXO3a siRNA. Moreover, silencing ARC by siRNA significantly blocked the antipyroptotic actions of melatonin, whereas ARC overexpression enhanced the antipyroptotic actions of melatonin in OGD/R-exposed H9c2 cells.Our findings demonstrated that melatonin prevented OGD/R-induced pyroptosis via regulating the MT2/miR-155/FOXO3a/ARC axis in cardiomyocytes.

E26 transformation-specific 1 is implicated in the inhibition of osteogenic differentiation induced by chronic high glucose by directly regulating Runx2 expression

Chronic high glucose (HG) plays a crucial role in the pathogenesis of diabetes-induced osteoporosis by inhibiting the differentiation and proliferation of osteoblasts. This study aims to examine the role of E26 transformation-specific 1 (ETS1) in the inhibition of osteoblast differentiation and proliferation caused by chronic HG, as well as the underlying mechanism. Chronic HG treatment downregulated ETS1 expression and inhibited differentiation and proliferation of MC3T3-E1 cells. Downregulation of ETS1 expression inhibited the differentiation and proliferation of MC3T3-E1 cells under normal glucose conditions, and ETS1 overexpression attenuated the damage to cells exposed to chronic HG. In addition, ETS1 overexpression reversed the decrease in runt-related transcription factor 2 (Runx2) expression in MC3T3-E1 cells treated with chronic HG. Using chromatin immunoprecipitation (ChIP) and luciferase reporter assays, we confirmed that ETS1 directly bound to and increased the activity of the Runx2 promoter. In summary, our study suggested that ETS1 was involved in the inhibitory effect of chronic HG on osteogenic differentiation and proliferation and may be a potential therapeutic target for diabetes-induced osteoporosis.

miRNAs Related to Different Processes of Fracture Healing: An Integrative Overview

Fracture healing is a complex, dynamic process that is directed by cellular communication and requires multiple cell types, such as osteoblasts, osteoclasts, and immune cells. Physiological fracture healing can be divided into several phases that consist of different processes, such as angiogenesis, osteogenesis, and bone resorption/remodelling. This is needed to guarantee proper bone regeneration after fracture. Communication and molecular regulation between different cell types and within cells is therefore key in successfully orchestrating these processes to ensure adequate bone healing. Among others, microRNAs (miRNAs) play an important role in cellular communication. microRNAs are small, non-coding RNA molecules of ~22 nucleotides long that can greatly influence gene expression by post-transcriptional regulation. Over the course of the past decade, more insights have been gained in the field of miRNAs and their role in cellular signalling in both inter- and intracellular pathways. The interplay between miRNAs and their mRNA targets, and the effect thereof on different processes and aspects within fracture healing, have shown to be interesting research topics with possible future diagnostic and therapeutic potential. Considering bone regeneration, research moreover focusses on specific microRNAs and their involvement in individual pathways. However, it is required to combine these data to gain more understanding on the effects of miRNAs in the dynamic process of fracture healing, and to enhance their translational application in research, as well as in the clinic. Therefore, this review aims to provide an integrative overview on miRNAs in fracture healing, related to several key aspects in the fracture healing cascade. A special focus will be put on hypoxia, angiogenesis, bone resorption, osteoclastogenesis, mineralization, osteogenesis, osteoblastogenesis, osteocytogenesis, and chondrogenesis.

Down-regulation of miR-340-5p promoted osteogenic differentiation through regulation of runt-related transcription factor-2 (RUNX2) in MC3T3-E1 cells

Diabetic osteoporosis (DOP) is a chronic complication of diabetes in the skeletal system. High level of miR-340-5p may be harmful to the bone formation. In this study, the DOP model of rats was successfully established via streptozotocin (STZ) and ovariectomy (OVX) treatment. It was manifested by reduced body weight, insulin level, alkaline phosphatase (ALP) activity, and osteocalcin (OCN) and collagen-I expressions, as well as increased concentration of fasting blood glucose. Moreover, we found that miR-340-5p expression was increased while runt-related transcription factor-2 (RUNX2) was decreased in femurs. Furthermore, the effects of miR-340-5p on osteogenic differentiation (OD) in high glucose (HG)-treated MC3T3-E1 cells were explored. Exposure to OD and HG contributed to elevated miR-340-5p level. Inhibition of miR-340-5p enhanced ALP level, calcium deposition, and OCN, collagen-I and RUNX2 levels. On the contrary, miR-340-5p overexpression reversed these promotional effects. Luciferase assay indicated that RUNX2 may be a target gene of miR-340-5p. Moreover, RUNX2 deficiency decreased miR-340-5p inhibition-induced ALP activity, calcium accumulation and OCN, collagen-I, RUNX2 levels. In short, the above findings revealed that inhibition of miR-340-5p facilitated osteogenic differentiation through regulating RUNX2 in MC3TC-E1 cells, which provided targeted therapeutic strategies for the treatment of DOP.

Circulating miR-122-5p and miR-375 as Potential Biomarkers for Bone Mass Recovery after Parathyroidectomy in Patients with Primary Hyperparathyroidism: A Proof-of-Concept Study

Primary hyperparathyroidism (PHPT) is the leading cause of secondary osteoporosis. Although bone mineral density (BMD) tends to recover after parathyroidectomy in PHPT patients, the degree of recovery varies. Circulating microRNAs (miRNAs) profiles are known to be correlated with osteoporosis and fracture. We aimed to investigate whether osteoporotic fracture-related miRNAs are associated with postoperative BMD recovery in PHPT. Here, 16 previously identified osteoporotic fracture-related miRNAs were selected. We analyzed the association between the preoperative level of each miRNA and total hip (TH) BMD change. All 12 patients (among the 18 patients enrolled) were cured of PHPT after parathyroidectomy as parathyroid hormone (PTH) and calcium levels were restored to the normal range. Preoperative miR-19b-3p, miR-122-5p, and miR-375 showed a negative association with the percent changes in TH BMD from baseline. The association remained robust for miR-122-5p and miR-375 even after adjusting for sex, age, PTH, and procollagen type 1 N-terminal propeptide levels in a multivariable model. In conclusion, preoperative circulating miR-122-5p and miR-375 levels were negatively associated with TH BMD changes after parathyroidectomy in PHPT patients. miRNAs have the potential to serve as predictive biomarkers of treatment response in PHPT patients, which merits further investigation.

LINC00899 promotes osteogenic differentiation by targeting miR-374a and RUNX2 expression

Accumulating researches indicate that long non-coding RNAs (lncRNAs) participate in human bone mesenchymal stem cells (hBMSCs) osteogenic differentiation. The present study aimed to investigate the underlying molecular mechanisms of long intergenic non-protein coding RNA 899 (LINC00899) in osteoporosis. Therefore, reverse transcription-quantitative PCR was performed to evaluate the expression levels of LINC00899, microRNA (miR)-374a and runt-related transcription factor 2 (RUNX2) in clinical tissues and hBMSCs. The potential interaction between miR-374a and LINC00899 or RUNX2 was predicted utilizing the StarBase software and verified by luciferase reporter and RNA binding protein immunoprecipitation assays. In addition, alkaline phosphatase activity and Alizarin Red S staining were used to evaluate the osteogenic potential of hBMSCs. The results showed that the expression levels of LINC00899 were gradually increased, whilst those of miR-374a were decreased as the osteogenic induction process progresses. Additionally, the expression of LINC00899 was downregulated in the bone tissues of patients with osteoporosis, where LINC00899 knockdown reduced the expression levels of osteogenesis-related genes osteocalcin (OCN), osteopontin (OPN) and RUNX2 in hBMSCs. LINC00899 was also found to directly target miR-374a, thereby inhibiting its expression. Finally, it was predicted that RUNX2 could be directly targeted by miR-374a, such that miR-374a silencing partially abolished the inhibitory effect of LINC00899 knockdown on the expression of RUNX2, OPN and OCN. Overall, findings of the present study suggested that LINC00899 could facilitate the osteogenic differentiation of hBMSCs and prevent osteoporosis by sponging miR-374a to enhance the expression of RUNX2, which provide a potentially useful therapeutic strategy for patients with osteoporosis.

MiR-486-3p promotes osteogenic differentiation of BMSC by targeting CTNNBIP1 and activating the Wnt/β-catenin pathway

BACKGROUND

Dysfunction in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) leads to bone loss/osteoporosis. The catenin beta interacting protein 1 (CTNNBIP1) is an inhibitor of Wnt/β-catenin signaling, whose role in osteogenesis remains elusive. This study aimed to reveal the effects of miR-486-3p/CTNNBIP1 in osteogenesis.

METHODS

Bone marrow samples from healthy individuals and osteoporosis patients and mice with sham or ovariectomy (OVX) surgeries were collected. Levels of CTNNBIP1 and miR-486-3p were assessed. A dual-luciferase reporter assay was used to confirm the interactions between CTNNBIP1 and miR-486-3p. MiR-486-3p mimics/inhibitor or CTNNBIP1 overexpression lentiviruses were transfected to human BMSCs (hBMSCs) and an osteogenic assay was performed. Alizarin red S (ARS) and Alkaline phosphatase (ALP) intensity and expression of osteogenic genes Runx2, Alp, Cola1 and Bglap were measured. Key proteins in the Wnt/β-catenin pathway including active β-catenin, Bcl-2, and Cyclin D1 were assessed.

RESULTS

CTNNBIP1 was upregulated while miR-486-3p was downregulated in osteoporosis patients and OVX mice. CTNNBIP1 was confirmed as a target of miR-486-3p. MiR-486-3p overexpression promoted, while miR-486-3p knockdown suppressed, osteogenic differentiation and Wnt/β-catenin signaling. Rescue experiments confirmed the negative effects of CTNNBIP1 overexpression on osteoblastic differentiation and that miR-486-3p mimics could reverse canonical Wnt signaling.

CONCLUSION

This study demonstrated that miR-486-3p targets CTNNBIP1, thus activating the Wnt/β-catenin signaling pathway to promote osteogenesis of BMSCs.

MALAT1 regulates osteogenic differentiation of human periodontal ligament stem cells through mediating miR-155-5p/ETS1 axis

BACKGROUND

Osteogenic differentiation of human periodontal ligament stem cells is essential to periodontal regeneration treatment for periodontitis. This study investigated the mechanism of lncRNAs-related osteogenic differentiation.

METHODS

Human periodontal ligament stem cells were extracted from human periodontal ligament and identified via flow cytometry. After being induced into osteogenic differentiation for three weeks using osteoblast inducing conditional media, human periodontal ligament stem cells were transfected with siRNA-MALAT1, or miR-155-5p inhibitor. Human periodontal ligament stem cells osteogenesis was observed by alkaline phosphatase staining, followed by alizarin red staining for evaluating mineralized nodes formation. Runt-related gene 2, collagen-1 and osteocalcin expressions were assessed by western blot and qRT-PCR.

RESULTS

MALAT1 expression was assumed a negative correlation with miR-155-5p expression which was dropping over time in differentiating human periodontal ligament stem cells. MALAT1 could bind with miR-155-5p, and E26 transformation specific-1 (ETS1) was the targeted gene of miR-155-5p. Silenced MALAT1 suppressed ALP activity and mineralized nodes formation and inhibited the expressions of runt-related gene 2, collagen-1 and osteocalcin in differentiating human periodontal ligament stem cells, while miR-155-5p inhibitor reversed the effect of si-MALAT1 on differentiation of human periodontal ligament stem cells.

CONCLUSION

MALAT1 modulated differentiation of human periodontal ligament stem cells via regulating miR-155-5p.

CRISPR/Cas9 uPAR Gene Knockout Results in Tumor Growth Inhibition, EGFR Downregulation and Induction of Stemness Markers in Melanoma and Colon Carcinoma Cell Lines

uPAR is a globular protein, tethered to the cell membrane by a GPI-anchor involved in several cancer-related properties and its overexpression commonly correlates with poor prognosis and metastasis. We investigated the consequences of uPAR irreversible loss in human melanoma and colon cancer cell lines, knocking out its expression by CRISPR/Cas9. We analyzed through flow cytometry, western blotting and qPCR, the modulation of the most known cancer stem cells-associated genes and the EGFR while we observed the proliferation rate exploiting 2D and 3D cellular models. We also generated uPAR “rescue” expression cell lines as well as we promoted the expression of only its 3’UTR to demonstrate the involvement of uPAR mRNA in tumor progression. Knocking out PLAUR, uPAR-encoding gene, we observed an inhibited growth ratio unexpectedly coupled with a significant percentage of cells acquiring a stem-like phenotype. In vivo experiments demonstrated that uPAR loss completely abrogates tumorigenesis despite the gained stem-like profile. Nonetheless, we proved that the reintroduction of the 3’UTR of PLAUR gene was sufficient to restore the wild-type status validating the hypothesis that such a region may act as a “molecular sponge”. In particular miR146a, by binding PLAUR 3’ UTR region might be responsible for uPAR-dependent inhibition of EGFR expression.

Estrogen promotes lncRNA H19 expression to regulate osteogenic differentiation of BMSCs and reduce osteoporosis via miR-532-3p/SIRT1 axis

Osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) plays an essential role in bone formation. Its imbalance can lead to osteoporosis. Estrogen and long noncoding RNAs (lncRNAs) have been confirmed to participate in osteogenesis. However, the underlying mechanism remains unclear. The purpose of our study was to explore the function of lncRNA H19 in estrogen-induced osteogenic differentiation of BMSCs. The present research demonstrated that the expression levels of lncRNA H19 and SIRT1 were markedly downregulated in postmenopausal osteoporosis (PMOP), while miR-532-3p expression was obviously increased. Moreover, estrogen induced the osteogenic differentiation of BMSCs by upregulating lncRNA H19. Furthermore, our integrated experiments showed that lncRNA H19 caused a decrease in the expression of miR-532-3p, which was verified to target SIRT1 directly. Additionally, estrogen alleviated osteoporosis in OVX rats through lncRNA H19-mediated miR-532-3p/SIRT1 axis. Our findings imply that lncRNA H19 mediates estrogen-regulated osteogenic differentiation in BMSCs via miR-532-3p/SIRT1 signalling and may become a novel target for alleviating PMOP.

Comparative profile of exosomal microRNAs in postmenopausal women with various bone mineral densities by small RNA sequencing

To explore the role of plasma miRNAs in exosomes in early postmenopausal women. Small RNA sequencing was implemented to clarify the expression of miRNA in plasma exosomes obtained from 15 postmenopausal women, divided into groups of osteoporosis, osteopenia, and normal bone mass based on bone mineral density. Differentially expressed miRNAs (DEMs) were identified by comparing miRNA expression profiles. Five putative miRNAs, miR-224-3p, miR-25-5p, miR-302a-3p, miR-642a-3p, and miR-766-5p were confirmed by real-time PCR; miRNA target genes were obtained from 4 databases: miRWalk, miRDB, RNA22, and TargetScan. The miRNA-mRNA- Kyoto Encyclopedia of Genes and Genomes (KEGG) networks were analyzed, and the DEMs' potential role was investigated by gene ontology terms and KEGG pathway annotation. The results suggest that characterizing plasma exosomal miRNA profiles of early postmenopausal women by small RNA sequencing could identify novel exo-miRNAs involved in bone remodeling, and miR-642a-3p maybe contribute to the prediction and diagnosis of early postmenopausal osteoporosis.

ETS Proto-Oncogene 1 Suppresses MicroRNA-128 Transcription to Promote Osteogenic Differentiation Through the HOXA13/β-Catenin Axis

ETS proto-oncogene 1 (ETS1) has been implicated in osteoporosis (OP), but the exact molecular mechanisms are complex. This work focuses on the impact of ETS1 on the osteogenic differentiation and the molecules involved. A mouse pre-osteoblast cell line MC3T3-E1 was used for in vitro experiments. ETS1 was upregulated during the process of osteogenic differentiation of MC3T3-E1 cells. Overexpression of ETS1 promoted expression of osteogenic markers, alkaline phosphate concentration, and calcareous accumulation in cells. ETS1 was found to specifically bind to miR-128 promoter to suppress its transcription, while miR-128 could target homeobox A13 (HOXA13). Therefore, ETS1 suppressed miR-128 transcription to upregulate HOXA13 expression. Overexpression of HOXA13 promoted the osteogenic differentiation ability of cells and increased the protein level of β-catenin. Either overexpression of miR-128 or downregulation of β-catenin by CWP232228, a β-catenin-specific antagonist, blocked the promoting roles of ETS1 in cells. To conclude, this study provided evidence that ETS1 suppresses miR-128 transcription to activate the following HOXA13/β-catenin axis, therefore promoting osteogenic differentiation ability of MC3T3-E1 cells. This finding may offer novel ideas for OP treatment.

LINC00963 affects the development of colorectal cancer via MiR-532-3p/HMGA2 axis

Background

LINC00963 is high-expressed in various carcinomas, but its expression and function in colorectal cancer (CRC) have not been explored. This study explored the role and mechanism of LINC00963 in CRC.

Methods

The expression of LINC00963 in CRC and its relationship with prognosis were examined by starBase and survival analysis. The effects of LINC00963, miR-532-3p and HMGA2 on the biological characteristics and EMT-related genes of CRC cells were studied by RT-qPCR, CCK-8, clone formation experiments, flow cytometry, scratch test, Transwell, and Western blot. Xenograft assay and immunohistochemistry were performed to verify the effect of LINC00963 on tumor growth. The correlation among LINC00963, miR-532-3p, and HMGA2 was analyzed by bioinformatics analysis, luciferase assay, and Pearson test.

Results

LINC00963 was high-expressed in CRC, and this was associated with poor prognosis of CRC. Silencing LINC00963 inhibited the activity, proliferation, migration, and invasion of CRC cells, MMP-3 and MMP-9 expressions, moreover, it also blocked cell cycle progression, and inhibited tumor growth and Ki67 expression. However, overexpression of LINC00963 showed the opposite effects to silencing LINC00963. LINC00963 targeted miR-532-3p to regulate HMGA2 expression. Down-regulation of miR-532-3p promoted cell proliferation, migration and invasion, and expressions of MMP-3 and MMP-9, and knockdown of HMGA2 reversed the effect of miR-532-3p inhibitor. Up-regulation of miR-532-3p inhibited the biological functions of CRC cells, and overexpression of HMGA2 reversed the miR-532-3p mimic effect.

Conclusion

LINC00963 affects the development of CRC through the miR-532-3p/HMGA2 axis.

Kaempferol promotes BMSC osteogenic differentiation and improves osteoporosis by downregulating miR-10a-3p and upregulating CXCL12

BACKGROUND

Kaempferol has improved the functions of various human diseases. Here, we aimed to probe into the potential molecular mechanism of Kaempferol to ameliorate osteoporosis.

METHODS

Micro-computed tomography scanning was applied to assess the bone density of osteoporosis rats induced by ovariectomized. Quantitative real-time PCR was applied to detect the expressions of RUNX2, Osterix, CXCL12, and miR-10a-3p. Western blot, Alizarin red staining, Alkaline Phosphatase Diethanolamine Activity Kit were applied to confirm the in vitro functions of Kaempferol. RNA Immunoprecipitation and dual-luciferase reporter gene experiments were applied to study the potential mechanism.

RESULTS

The treatment of Kaempferol raised bone density in osteoporosis rats induced by ovariectomized, and boosted the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and raised the expressions of RUNX2, Osterix, and CXCL12, and lessened miR-10a-3p. From the potential mechanism analysis, we corroborated that miR-10a-3p and CXCL12 bound to each other, and Kaempferol boosted BMSC osteogenic differentiation and ameliorated osteoporosis by lessening miR-10a-3p and raising CXCL12.

CONCLUSION

Our data expounded that Kaempferol boosted BMSC osteogenic differentiation and ameliorated osteoporosis by lessening miR-10a-3p and raising CXCL12.