MiR-1224-5p modulates osteogenesis by coordinating osteoblast/osteoclast differentiation via the Rap1 signaling target ADCY2

Loss of BACH1 improves osteogenic differentiation in glucocorticoid-induced hBMSCs through restoring autophagy

BACKGROUND

Glucocorticoid-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Recently, autophagy has been found to be related with the development of various diseases, including osteoporosis and osteoblast differentiation regulations. BTB and CNC homology 1 (BACH1) was a previously confirmed regulator for osteoblast differentiation, but whether it's could involve in glucocorticoid-induced human bone mesenchymal stem cells (hBMSCs) differentiation and autophagy regulation remain not been elucidated.

METHODS

hBMSCs were identified by flow cytometry method, and its differentiation ability were measured by ARS staining, oil O red, and Alcian blue staining assays. Gene and proteins were quantified via qRT-PCR and western blot assays, respectively. Autophagy activity was determined using immunofluorescence. ChIP and dual luciferase assay validated the molecular interactions.

RESULTS

The data revealed that isolated hBMSCs exhibited positive of CD29/CD44 and negative CD45/CD34. Moreover, BACH1 was abated gradually during osteoblast differentiation of hBMSCs, while dexamethasone (Dex) treatment led to BACH1 upregulation. Loss of BACH1 improved osteoblast differentiation and activated autophagy activity in Dex-challenged hBMSCs. Autophagy-related proteins (ATG3, ATG4, ATG5, ATG7, ATG12) were repressed after Dex treatment, while ATG3, ATG7 and BECN1 could be elevated by BACH1 knockdown, especially ATG7. Moreover, BACH1 could interact ATG7 promoter region to inhibit its transcription. Co-inhibition of ATG7 greatly overturned the protective roles of BACH1 loss on osteoblast differentiation and autophagy in Dex-induced hBMSCs.

CONCLUSION

Taken together, our results demonstrated that silencing of BACH1 mitigated Dex-triggered osteogenic differentiation inhibition by transcriptionally activating ATG7-mediated autophagy, suggesting that BACH1 may be a therapeutic target for GIOP treatment.

Identification of a G-protein coupled receptor-related gene signature through bioinformatics analysis to construct a risk model for ovarian cancer prognosis

BACKGROUND

Ovarian cancer (OV) is a common malignant tumor of the female reproductive system with a 5-year survival rate of ∼30 %. Inefficient early diagnosis and prognosis leads to poor survival in most patients. G protein-coupled receptors (GPCRs, the largest family of human cell surface receptors) are associated with OV. We aimed to identify GPCR-related gene (GPCRRG) signatures and develop a novel model to predict OV prognosis.

METHOD

We downloaded data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Prognostic GPCRRGs were screened using least absolute shrinkage and selection operator (LASSO) Cox regression analysis, and a prognostic model was constructed. The predictive ability of the model was evaluated by Kaplan-Meier (K-M) survival analysis. The levels of GPCRRGs were examined in normal and OV cell lines using quantitative reverse-Etranscription polymerase chain reaction. The immunological characteristics of the high- and low-risk groups were analyzed using single-sample gene set enrichment analysis (ssGSEA) and CIBERSORT.

RESULTS

Based on the risks scores, 17 GPCRRGs were associated with OV prognosis. CXCR4, GPR34, LGR6, LPAR3, and RGS2 were significantly expressed in three OV datasets and enabled accurate OV diagnosis. K-M analysis of the prognostic model showed that it could differentiate high- and low-risk patients, which correspond to poorer and better prognoses, respectively. GPCRRG expression was correlated with immune infiltration rates.

CONCLUSIONS

Our prognostic model elaborates on the roles of GPCRRGs in OV and provides a new tool for prognosis and immune response prediction in patients with OV.

Zhuang-Gu-Fang promotes osteoblast differentiation via myoblasts and myoblast-derived exosomal miRNAs:miR-5100, miR-126a-3p, miR-450b-5p, and miR-669a-5p

BACKGROUND

Senile osteoporosis (SOP) is an age-related systemic metabolic bone disorder. Previous studies have proved that Zhuang-Gu-Fang (ZGF) modulates myokines, stimulates osteogenic differentiation, and mitigates osteoporosis.

OBJECTIVE

To elucidate the mechanism by which ZGF promotes osteogenic differentiation via myoblast and myoblast exosomal microRNAs (miRNAs) and investigate its potential implications in senile osteoporosis.

METHODS

Characterization of ZGF and ZGF serum using UHPLC-MS/MS. An alkaline phosphatase (ALP) activity assay and staining techniques were employed to corroborate the impacts of ZGF on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) via myoblasts. Subsequently, exosomes derived from myoblasts were isolated through ultracentrifugation. The effects of ZGF on the BMSCs' osteogenic differentiation were substantiated through ALP activity, alizarin red staining, and a quantitative real-time polymerase reaction system (qRT-PCR). Selected miRNAs were identified via high-throughput sequencing and subjected to differential expression analysis, and subsequently validated through qRT-PCR. The senescence-accelerated (SAMP6) mice were selected as the SOP models. qRT-PCR analyses were further conducted to confirm the expression levels of these selected miRNAs in the muscle and bone tissues of the SAMP6 mice, and the protein expression of osteogenesis-related transcription factors OCN and Osterix in its bone tissue was evaluated by immunofluorescence staining analysis (IF).

RESULTS

ZGF may enhance the osteogenic differentiation of BMSCs through myoblasts and myoblast-derived exosomes. High-throughput sequencing, differential expression analysis, and subsequent qRT-PCR validation identified four miRNAs that stood out due to their significant differential expression: miR-5100, miR-142a-3p, miR-126a-3p, miR-450b-5p and miR-669a-5p. Moreover, the mice experiment corroborated these findings, which revealed that ZGF not only up-regulated the expression of miR-5100, miR-450b-5p and miR-126a-3p in muscle and bone tissues but also concurrently down-regulated the expression of miR-669a-5p in these tissues. IF staining analysis indicated that ZGF can significantly increase the protein expression of the osteogenic transcription factors OCN and Osterix in the bone tissue of mice with SOP.

CONCLUSIONS

ZGF can promote osteogenic differentiation of osteoblasts, regulate bone metabolism, and thereby delay the process of SOP. Perhaps, its mechanism is to upregulate myoblast-derived exosomes miR-5100, miR-126a-3p, and miR-450b-5p or downregulate miR-669a-5p. This study reports for the first time that myoblast exosomes miR-669a-5p and miR-450b-5p are novel targets for the regulation of osteoblastic differentiation and the treatment of SOP.

The Involvement of microRNAs in Bone Remodeling Signaling Pathways and Their Role in the Development of Osteoporosis

Bone remodeling, crucial for maintaining the balance between bone resorption and formation, relies on the coordinated activity of osteoclasts and osteoblasts. During osteoclastogenesis, hematopoietic stem cells (HSCs) differentiate into the osteoclast lineage through the signaling pathways OPG/RANK/RANKL. On the other hand, during osteoblastogenesis, mesenchymal stem cells (MSCs) differentiate into the osteoblast lineage through activation of the signaling pathways TGF-β/BMP/Wnt. Recent studies have shown that bone remodeling is regulated by post-transcriptional mechanisms including microRNAs (miRNAs). miRNAs are small, single-stranded, noncoding RNAs approximately 22 nucleotides in length. miRNAs can regulate virtually all cellular processes through binding to miRNA-response elements (MRE) at the 3' untranslated region (3'UTR) of the target mRNA. miRNAs are involved in controlling gene expression during osteogenic differentiation through the regulation of key signaling cascades during bone formation and resorption. Alterations of miRNA expression could favor the development of bone disorders, including osteoporosis. This review provides a general description of the miRNAs involved in bone remodeling and their significance in osteoporosis development.

A Machine Learning Framework for Screening Plasma Cell-Associated Feature Genes to Estimate Osteoporosis Risk and Treatment Vulnerability

Osteoporosis, in which bones become fragile owing to low bone density and impaired bone mass, is a global public health concern. Bone mineral density (BMD) has been extensively evaluated for the diagnosis of low bone mass and osteoporosis. Circulating monocytes play an indispensable role in bone destruction and remodeling. This work proposed a machine learning-based framework to investigate the impact of circulating monocyte-associated genes on bone loss in osteoporosis patients. Females with discordant BMD levels were included in the GSE56815, GSE7158, GSE7429, and GSE62402 datasets. Circulating monocyte types were quantified via CIBERSORT, with subsequent selection of plasma cell-associated DEGs. Generalized linear models, random forests, extreme gradient boosting (XGB), and support vector machines were adopted for feature selection. Artificial neural networks and nomograms were subsequently constructed for osteoporosis diagnosis, and the molecular machinery underlying the identified genes was explored. SVM outperformed the other tuned models; thus, the expression of several genes (DEFA4, HLA-DPB1, LCN2, HP, and GAS7) associated with osteoporosis were determined. ANNs and nomograms were proposed to robustly distinguish low and high BMDs and estimate the risk of osteoporosis. Clozapine, aspirin, pyridoxine, etc. were identified as possible treatment agents. The expression of these genes is extensively posttranscriptionally regulated by miRNAs and m6A modifications. Additionally, they participate in modulating key signaling pathways, e.g., autophagy. The machine learning framework based on plasma cell-associated feature genes has the potential for estimating personalized risk stratification and treatment vulnerability in osteoporosis patients.

CircFgfr2 promotes osteogenic differentiation of rat dental follicle cells by targeting the miR-133a-3p/DLX3 signaling pathway

Dental follicle cells (DFCs) promote bone regeneration in vivo and in vitro. Circular RNAs (circRNAs) play crucial roles in bone development and regeneration. Our previous study demonstrated the upregulation of circFgfr2 expression during the osteogenic differentiation of DFCs. However, the molecular mechanisms and functional roles of circFgfr2 in DFCs osteogenesis remain unclear. In this study, we aimed to investigate the subcellular localization of circFgfr2 in DFCs using fluorescence in situ hybridization. In vitro investigations demonstrated that circFgfr2 overexpression promoted osteogenic differentiation, as evidenced by real-time quantitative polymerase chain reaction. By integrating the outcomes of bioinformatics analyses, dual luciferase reporter experiments, and chromatin isolation by RNA purification, we identified circFgfr2 as a sponge for miR-133a-3p, a key regulator of osteogenic differentiation. Moreover, miR-133a-3p suppressed osteogenic differentiation by targeting DLX3 and RUNX2 in DFCs. We validated that circFgfr2 promoted the osteogenic differentiation of DFCs through the miR-133a-3p/DLX3 axis. To further investigate the therapeutic potential of circFgfr2 in bone regeneration, we conducted in vivo experiments and histological analyses. Overall, these results confirmed the crucial role of circFgfr2 in promoting osteogenesis. In summary, our findings demonstrated that the circFgfr2/miR-133a-3p/DLX3 pathway acts as a cascade, thereby identifying circFgfr2 as a promising molecular target for bone tissue engineering.

The nano-artificial periosteum made of PCL/MgO/AS-IV enhances MC3T3-E1 cell osteogenic differentiation and promotes bone defect repair via the EphB4/EphrinB2 signaling pathway

Bone regeneration plays a pivotal role in periodontal tissue repair. With advancements in biotechnology materials, the utilization of nanotechnology offers a reliable platform for bone restoration in periodontitis. In this study, we successfully established a long-term bacterial infection model using Porphyromonas gingivalis (P. gingivalis) with MOI = 50. CCK-8 and ROS immunofluorescence results demonstrated that the combined effect of Mg2+ and AS-IV significantly enhanced cell proliferation and effectively suppressed the inflammatory response during bacterial infection. Alkaline phosphatase and alizarin red staining revealed that the synergistic action of Mg2+ and AS-IV notably promoted osteogenic differentiation of MC3T3-E1 cells under P. gingivalis-infected conditions. Considering the properties of these two biomaterials, we fabricated polycaprolactone (PCL) artificial periosteum loaded with MgO and AS-IV using an electrostatic spinning technique. The findings indicated that PCL/MgO/AS-IV artificial periosteum exhibited excellent biocompatibility and hydrophilicity, thereby substantially enhancing cellular adhesion to its surface as well as augmenting cellular value-added rate. Moreover, efficient drug release from the PCL/MgO/AS-IV artificial bone membrane conferred remarkable antimicrobial activity along with in vitro osteogenic potentiality. The in vivo experiments conducted on animals further substantiated the exceptional properties exhibited by PCL/MgO/AS-IV artificial periosteum in bone defect repair. Additionally, it was observed that PCL/MgO/AS-IV artificial periosteum could modulate EphB4-EphrinB2 signaling to enhance osteogenic differentiation under P.gingivalis-infected conditions.This exciting outcome suggests that PCL/MgO/AS-IV artificial periosteum holds great promise as a biomaterial for treating periodontal bone loss.

MicroRNA‑1224 inhibits cell proliferation by downregulating CBX3 expression in chordoma

MicroRNAs (miRNAs/miRs) have abnormal expression in numerous tumors and are closely related to tumor development and resistance to radiotherapy and chemotherapy. However, there are few studies assessing the role and mechanism of miRNA in chordoma. The sequencing data of three pairs of chordoma and notochord tissues from the GSE56183 dataset were analyzed in the present study. Cell proliferation was assessed in vitro using Cell Counting Kit-8. Bioinformatics analysis and the dual luciferase reporter assay were used to evaluate the regulatory relationship between miR-1224 and chromobox 3 (CBX3) in chordoma. The results demonstrated that miR-1224 had a significantly lower expression level in chordoma tissues and cell lines. Overexpression of miR-1224 inhibited proliferation in the chordoma cells, while the knockdown of miR-1224 promoted proliferation of the chordoma cells. Bioinformatics analysis and the dual luciferase reporter assay confirmed that CBX3 was a direct target gene of miR-1224 and that miR-1224 induced the proliferation of chordoma cells through the inhibition of CBX3. In summary, miR-1224 reduced the proliferation of chordoma cells through inhibition of CBX3, which provides a theoretical basis for selecting a novel therapeutic target for chordoma.

DDIT3 deficiency accelerates bone remodeling during bone healing by enhancing osteoblast and osteoclast differentiation through ULK1-mediated autophagy

The coordination of osteoblasts and osteoclasts is essential for bone remodeling. DNA damage inducible script 3 (DDIT3) is an important regulator of bone and participates in cell differentiation, proliferation, autophagy, and apoptosis. However, its role in bone remodeling remains unexplored. Here, we found that Ddit3 knockout (Ddit3-KO) enhanced both bone formation and resorption. The increased new bone formation and woven bone resorption, i.e., enhanced bone remodeling capacity, was found to accelerate bone defect healing in Ddit3-KO mice. In vitro experiments showed that DDIT3 inhibited both osteoblast differentiation and Raw264.7 cell differentiation by regulating autophagy. Cell coculture assay showed that Ddit3-KO decreased the ratio of receptor activator of nuclear factor-κβ ligand (RANKL) to osteoprotegerin (OPG) in osteoblasts, and Ddit3-KO osteoblasts inhibited osteoclast differentiation. Meanwhile, DDIT3 knockdown (DDIT3-sh) increased receptor activator of nuclear factor-κβ (RANK) expression in Raw264.7 cells, and DDIT3-sh Raw264.7 cells promoted osteoblast differentiation, whereas, DDIT3 overexpression had the opposite effect. Mechanistically, DDIT3 promoted autophagy partly by increasing ULK1 phosphorylation at serine555 (pULK1-S555) and decreasing ULK1 phosphorylation at serine757 (pULK1-S757) in osteoblasts, thereby inhibiting osteoblast differentiation. DDIT3 inhibited autophagy partly by decreasing pULK1-S555 in Raw264.7 cells, thereby suppressing osteoclastic differentiation. Taken together, our data indicate that DDIT3 is one of the elements regulating bone remodeling and bone healing, which may become a potential target in bone defect treatment.

Identification of ceRNA networks in type H and L vascular endothelial cells through integrated bioinformatics methods

OBJECTIVES

Type H blood vessels are a subtype of bone-specific microvessels (CD31hiEmcnhi) that play an important regulatory role in the coupling of angiogenesis and osteogenesis. Despite reports on the distinct roles of type H and L vessels under physiological and pathological bone conditions, their genetic differences remain to be elucidated. This study aims to construct a competitive endogenous RNA (ceRNA) network of key gene for differencial expression (DE) in type H and L vascular endothelial cells (ECs) through integrated bioinformatic methods.

METHODS

We downloaded relevant raw data from the ArrayExpress and the Gene Expression Omnibus (GEO) database and used the Limma R-Bioconductor package to screen for DE lncRNAs, DE miRNAs, and DE mRNAs between type H and L vascular ECs. A total ceRNA network was constructed based on their interactions, followed by refinement using protein-protein interaction (PPI) networks to select upregulated and downregulated key genes. Enrichment analysis was performed on these key genes. Random validation was conducted using flow cytometry and real-time RT-PCR.

RESULTS

A total of 1 761 DE mRNAs, 187 DE lncRNAs, and 159 DE miRNAs were identified, and a comprehensive ceRNA network was constructed based on their interactions. Six upregulated (Itga5, Kdr, Tjp1, Pecam1, Cdh5, and Ptk2) and 2 downregulated (Csf1r and Il10) key genes were selected via PPI network to construct a subnetwork of ceRNAs related to these key genes. Upregulated key genes were mainly enriched in negative regulation of angiogenesis and vascular apoptosis. Results from flow cytometry and real-time RT-PCR were consistent with bioinformatics analysis.

CONCLUSIONS

This study proposes a ceRNA network associated with upregulated and downregulated type H and L vascular ECs based on selected key genes, providing new insights into the regulatory mechanisms of type H and L vascular ECs in bone metabolism.

MicroRNAs in osteoblast differentiation and fracture healing: From pathogenesis to therapeutic implication

The term "fracture" pertains to the occurrence of bones being either fully or partially disrupted as a result of external forces. Prolonged fracture healing can present a notable danger to the patient's general health and overall quality of life. The significance of osteoblasts in the process of new bone formation is widely recognized, and optimizing their function could be a desirable strategy. Therefore, the mending of bone fractures is intricately linked to the processes of osteogenic differentiation and mineralization. MicroRNAs (miRNAs) are RNA molecules that do not encode for proteins, but rather modulate the functioning of physiological processes by directly targeting proteins. The participation of microRNAs (miRNAs) in experimental investigations has been extensive, and their control functions have earned them the recognition as primary regulators of the human genome. Earlier studies have shown that modulating the expression of miRNAs, either by increasing or decreasing their levels, can initiate the differentiation of osteoblasts. This implies that miRNAs play a pivotal function in promoting osteogenesis, facilitating bone mineralization and formation, ultimately leading to an efficient healing of fractures. Hence, focusing on miRNAs can be considered a propitious therapeutic approach to accelerate the healing of fractures and forestall nonunion. In this manner, the information supplied by this investigation has the potential to aid in upcoming clinical utilization, including its possible use as biomarkers or as resources for devising innovative therapeutic tactics aimed at promoting fracture healing.

Neddylation suppression by a macrophage membrane-coated nanoparticle promotes dual immunomodulatory repair of diabetic wounds

Oxidative stress, infection, and vasculopathy caused by hyperglycemia are the main barriers for the rapid repair of foot ulcers in patients with diabetes mellitus (DM). In recent times, the discovery of neddylation, a new type of post-translational modification, has been found to regulate various crucial biological processes including cell metabolism and the cell cycle. Nevertheless, its capacity to control the healing of wounds in diabetic patients remains unknown. This study shows that MLN49224, a compound that inhibits neddylation at low concentrations, enhances the healing of diabetic wounds by inhibiting the polarization of M1 macrophages and reducing the secretion of inflammatory factors. Moreover, it concurrently stimulates the growth, movement, and formation of blood vessel endothelial cells, leading to expedited healing of wounds in individuals with diabetes. The drug is loaded into biomimetic macrophage-membrane-coated PLGA nanoparticles (M-NPs/MLN4924). The membrane of macrophages shields nanoparticles from being eliminated in the reticuloendothelial system and counteracts the proinflammatory cytokines to alleviate inflammation in the surrounding area. The extended discharge of MLN4924 from M-NPs/MLN4924 stimulates the growth of endothelial cells and the formation of tubes, along with the polarization of macrophages towards the anti-inflammatory M2 phenotype. By loading M-NPs/MLN4924 into a hydrogel, the final formulation is able to meaningfully repair a diabetic wound, suggesting that M-NPs/MLN4924 is a promising engineered nanoplatform for tissue engineering.

[Research Progress in the Regulatory Role of circRNA-miRNA Network in Bone Remodeling]

The dynamic balance between bone formation and bone resorption is a critical process of bone remodeling. The imbalance of bone formation and bone resorption is closely associated with the occurrence and development of various bone-related diseases. Under both physiological and pathological conditions, non-coding RNAs (ncRNAs) play a crucial regulatory role in protein expression through either inhibiting mRNAs translation or promoting mRNAs degradation. Circular RNAs (circRNAs) are a type of non-linear ncRNAs that can resist the degradation of RNA exonucleases. There is accumulating evidence suggesting that circRNAs and microRNAs (miRNAs) serve as critical regulators of bone remodeling through their direct or indirect regulation of the expression of osteogenesis-related genes. Additionally, recent studies have revealed the involvement of the circRNAs-miRNAs regulatory network in the process by which mesenchymal stem cells (MSCs) differentiate towards the osteoblasts (OB) lineage and the process by which bone marrow-derived macrophages (BMDM) differentiate towards osteoclasts (OC). The circRNA-miRNA network plays an important regulatory role in the osteoblastic-osteoclastic balance of bone remodeling. Therefore, a thorough understanding of the circRNA-miRNA regulatory mechanisms will contribute to a better understanding of the regulatory mechanisms of the balance between osteoblastic and osteoclastic activities in the process of bone remodeling and the diagnosis and treatment of related diseases. Herein, we reviewed the functions of circRNA and microRNA. We also reviewed their roles in and the mechanisms of the circRNA-miRNA regulatory network in the process of bone remodeling. This review provides references and ideas for further research on the regulation of bone remodeling and the prevention and treatment of bone-related diseases.

Multi-modal molecular determinants of clinically relevant osteoporosis subtypes

Due to a rapidly aging global population, osteoporosis and the associated risk of bone fractures have become a wide-spread public health problem. However, osteoporosis is very heterogeneous, and the existing standard diagnostic measure is not sufficient to accurately identify all patients at risk of osteoporotic fractures and to guide therapy. Here, we constructed the first prospective multi-omics atlas of the largest osteoporosis cohort to date (longitudinal data from 366 participants at three time points), and also implemented an explainable data-intensive analysis framework (DLSF: Deep Latent Space Fusion) for an omnigenic model based on a multi-modal approach that can capture the multi-modal molecular signatures (M3S) as explicit functional representations of hidden genotypes. Accordingly, through DLSF, we identified two subtypes of the osteoporosis population in Chinese individuals with corresponding molecular phenotypes, i.e., clinical intervention relevant subtypes (CISs), in which bone mineral density benefits response to calcium supplements in 2-year follow-up samples. Many snpGenes associated with these molecular phenotypes reveal diverse candidate biological mechanisms underlying osteoporosis, with xQTL preferences of osteoporosis and its subtypes indicating an omnigenic effect on different biological domains. Finally, these two subtypes were found to have different relevance to prior fracture and different fracture risk according to 4-year follow-up data. Thus, in clinical application, M3S could help us further develop improved diagnostic and treatment strategies for osteoporosis and identify a new composite index for fracture prediction, which were remarkably validated in an independent cohort (166 participants).

Macrophage exosomes modified by miR-365-2-5p promoted osteoblast osteogenic differentiation by targeting OLFML1

In the bone immune microenvironment, immune cells can regulate osteoblasts through a complex communication network. Macrophages play a central role in mediating immune osteogenesis, exosomes derived from them have osteogenic regulation and can be used as carriers in bone tissue engineering. However, there are problems with exosomal therapy alone, such as poor targeting, and the content of loaded molecules cannot reach the therapeutic concentration. In this study, macrophage-derived exosomes modified with miR-365-2-5p were developed to accelerate bone healing. MC3T3-E1 cells were incubated with the culture supernatants of M0, M1 and M2 macrophages, and it was found that the culture medium of M2 macrophages had the most significant effects in contributing to osteogenesis. High-throughput sequencing identified that miR-365-2-5p was significantly expressed in exosomes derived from M2 macrophages. We incubated MC3T3-E1 with exosomes overexpressing or knocking down miR-365-2-5p to examine the biological function of exosome miR-365-2-5p on MC3T3-E1 differentiation. These findings suggested that miR-365-2-5p secreted by exosomes increased the osteogenesis of MC3T3-E1. Moreover, miR-365-2-5p had a direct influence over osteogenesis for MC3T3-E1. Sequencing analysis combined with dual luciferase detection indicated that miR-365-2-5p binded to the 3'-UTR of OLFML1. In summary, exosomes secreted by M2 macrophages targeted OLFML1 through miR-365-2-5p to facilitate osteogenesis.

CD97 inhibits osteoclast differentiation via Rap1a/ERK pathway under compression

Acceleration of tooth movement during orthodontic treatment is challenging, with osteoclast-mediated bone resorption on the compressive side being the rate-limiting step. Recent studies have demonstrated that mechanoreceptors on the surface of monocytes/macrophages, especially adhesion G protein-coupled receptors (aGPCRs), play important roles in force sensing. However, its role in the regulation of osteoclast differentiation remains unclear. Herein, through single-cell analysis, we revealed that CD97, a novel mechanosensitive aGPCR, was expressed in macrophages. Compression upregulated CD97 expression and inhibited osteoclast differentiation; while knockdown of CD97 partially rescued osteoclast differentiation. It suggests that CD97 may be an important mechanosensitive receptor during osteoclast differentiation. RNA sequencing analysis showed that the Rap1a/ERK signalling pathway mediates the effects of CD97 on osteoclast differentiation under compression. Consistently, we clarified that administration of the Rap1a inhibitor GGTI298 increased osteoclast activity, thereby accelerating tooth movement. In conclusion, our results indicate that CD97 suppresses osteoclast differentiation through the Rap1a/ERK signalling pathway under orthodontic compressive force.

Mechanism of Circ_HECW2 regulating osteoblast apoptosis in osteoporosis by attenuating the maturation of miR-1224-5p

BACKGROUND

Osteoporosis (OP) poses a significant clinical challenge with escalating morbidity. This study explores Circ_HECW2 expression in OP patients and its regulatory role in lipopolysaccharide (LPS)-induced osteoblast apoptosis.

METHODS

Circ_HECW2 expression in OP patient serum and healthy controls was quantified using RT-qPCR. Diagnostic value of Circ_HECW2 for OP was assessed via ROC curve. Pearson's correlation model examined associations between indicators. Human osteoblasts HFOB1.19, treated with LPS, were analyzed for Circ_HECW2, pre-miR-1224, miR-1224-5p, and PDK2 mRNA levels. TUNEL assay determined cell apoptosis and Western blot assessed cleaved-caspase-3 protein levels. RNase R resistance assay and actinomycin D assay confirmed Circ_HECW2's cyclic structure. RNA pull-down and dual-luciferase reporter assay verified binding relationships between Circ_HECW2 and miR-1224 and between miR-1224-5p and PDK2.

RESULTS

Circ_HECW2 exhibited elevated expression in OP patients with diagnostic significance and a negative correlation with lumbar T-score. LPS co-culture increased Circ_HECW2 expression in HFOB1.19 cells, significantly elevating apoptosis index and cleaved-caspase-3. Circ_HECW2 downregulation inhibited HFOB1.19 apoptosis, reduced pre-miR-1224 expression, and elevated mature miR-1224-5p. Circ_HECW2 bound to pre-miR-1224, and inhibiting miR-1224-5p reversed the effect of Circ_HECW2 downregulation on osteoblast apoptosis. miR-1224-5p targeted PDK2 transcription.

CONCLUSION

Circ_HECW2, highly expressed in OP, holds diagnostic significance and reflects disease severity. Circ_HECW2 reduces mature miR-1224-5p by binding to pre-miR-1224, upregulating PDK2, and facilitating LPS-induced osteoblast apoptosis.

What happens to the osteoporotic bone mesenchymal stem cells? Evidence from RNA sequencing

Evidence presented that osteoporosis is closely related to the dysfunction of bone mesenchymal stem cells (BMSCs). But most studies are insufficient to reveal what actually happens to the osteoporotic BMSCs. In this study, BMSCs were harvested from ovariectomized and sham-operated rats. After checking the characteristics of rat models and stem cells, the BMSCs were carried out for RNA sequencing. Part of the findings were verified that seven mRNAs (Abi3bp, Aifm3, Ccl11, Cdkn1c, Chst10, Id2, Vcam1) were significantly up-regulated in osteoporotic BMSCs while seven mRNAs (Cep63, Fgfr3, Myc, Omd, Pou2f1, Smarcal1, Timm10b) were down-regulated. In addition, potential miRNA-mRNA and lncRNA-mRNA regulatory networks were illustrated. The changes in osteoporotic BMSCs covered a large set of biological processes, including cell viability, differentiation, immunoreaction, bone repairment and estrogen defect. This study enriched the pathophysiological mechanisms of BMSCs and osteporosis, as well as provided dozens of attractive RNA targets for further treatment.

Glipizide Alleviates Periodontitis Pathogenicity via Inhibition of Angiogenesis, Osteoclastogenesis and M1/M2 Macrophage Ratio in Periodontal Tissue

New consensus indicates type 2 diabetes mellitus (T2DM) and periodontitis as comorbidity and may share common pathways of disease progression. Sulfonylureas have been reported to improve the periodontal status in periodontitis patients. Glipizide, a sulfonylurea widely used in the treatment of T2DM, has also been reported to inhibit inflammation and angiogenesis. The effect of glipizide on the pathogenicity of periodontitis, however, has not been studied. We developed ligature-induced periodontitis in mice and treated them with different concentrations of glipizide and then analyzed the level of periodontal tissue inflammation, alveolar bone resorption, and osteoclast differentiation. Inflammatory cell infiltration and angiogenesis were analyzed using immunohistochemistry, RT-qPCR, and ELISA. Transwell assay and Western bolt analyzed macrophage migration and polarization. 16S rRNA sequencing analyzed the effect of glipizide on the oral microbial flora. mRNA sequencing of bone marrow-derived macrophages (BMMs) stimulated by P. gingivalis lipopolysaccharide (Pg-LPS) after treatment with glipizide was analyzed. Glipizide decreases alveolar bone resorption, periodontal tissue degradation, and the number of osteoclasts in periodontal tissue affected by periodontitis (PAPT). Glipizide-treated periodontitis mice showed reduced micro-vessel density and leukocyte/macrophage infiltration in PAPT. Glipizide significantly inhibited osteoclast differentiation in vitro experiments. Glipizide treatment did not affect the oral microbiome of periodontitis mice. mRNA sequencing and KEGG analysis showed that glipizide activated PI3K/AKT signaling in LPS-stimulated BMMs. Glipizide inhibited the LPS-induced migration of BMMs but promoted M2/M1 macrophage ratio in LPS-induced BMMs via activation of PI3K/AKT signaling. In conclusion, glipizide inhibits angiogenesis, macrophage inflammatory phenotype, and osteoclastogenesis to alleviate periodontitis pathogenicity suggesting its' possible application in the treatment of periodontitis and diabetes comorbidity.

circSLC25A13 acts as a ceRNA to regulate AML progression via miR-616-3p/ADCY2 axis

Circular RNAs (circRNAs), a type of endogenous noncoding RNA (ncRNA), exert vital roles in leukemia progression and are promising prognostic factors. Here, we report a novel circRNA, circSLC25A13 (hsa_circ_0081188), which was increased in acute myeloid leukemia (AML) patients with poor overall survival (OS) comparing to patients with good prognosis. Knockdown of circSLC25A13 in AML cells inhibited proliferation and increased cell apoptosis in vitro and in vivo. Enhanced circSLC25A13 expression promoted the survival of AML cells. Mechanistically, circSLC25A13 played as a microRNA sponge of miR-616-3p, which inhibited the expression of adenylate cyclase 2 (ADCY2). Downregulation of miR-616-3p and overexpression of ADCY2 partially rescued circSLC25A13 deficient induced cell growth arrest. In summary, through competitive absorption of miR-616-3p and thereby upregulating ADCY2 expression, circSLC25A13 promoted AML progression. Moreover, circSLC25A13 may represent a potential novel biomarker for the prognosis of AML and offer a potential therapeutic target for AML treatment.

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.

Isoimperatorin attenuates bone loss by inhibiting the binding of RANKL to RANK

Osteoporosis, an immune disease characterized by bone mass loss and microstructure destruction, is often seen in postmenopausal women. Isoimperatorin (ISO), a bioactive, natural furanocoumarin isolated from many traditional Chinese herbal medicines, has therapeutic effects against various diseases; however, its effect on bone homeostasis remains unclear. In this study, we investigated the effect of ISO on the differentiation and activation of osteoclast and its molecular mechanism in vitro, and evaluated the effect of ISO on bone metabolism by ovariectomized (OVX) rat model. In vitro experiments showed that ISO affected RANKL-induced MAPK, NFAT, NFATc1 trafficking and expression, osteoclast F-actin banding, osteoclast-characteristic gene expression, ROS inhibitory activity, and calcium oscillations, NF-κB signaling pathway. In vivo experiments showed that oral administration of ISO effectively reduced bone loss caused by ovariectomy and retained bone mass.Collectively, ISO inhibits RANK/RANKL binding, thereby reducing the activity of NFATc1, calcium, and ROS and inhibiting osteoclast generation. In addition, ISO protects bone mass by slowing osteoclast production and downregulating NFATc1 gene and protein expression in the bone tissue microenvironment and inhibits OVX-induced bone loss in vivo.

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study

Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), osteoporosis, gout, hyperthyroidism, hypothyroidism and others. The term 'epigenetics' was firstly proposed in 1942 and with the development of technologies, the exploration of epigenetics has made great progresses. There are four main epigenetic mechanisms, including DNA methylation, histone modification, chromatin remodelling, and noncoding RNA (ncRNA), which exert different effects on metabolic diseases. Genetic and non-genetic factors, including ageing, diet, and exercise, interact with epigenetics and jointly affect the formation of a phenotype. Understanding epigenetics could be applied to diagnosing and treating metabolic diseases in the clinic, including epigenetic biomarkers, epigenetic drugs, and epigenetic editing. In this review, we introduce the brief history of epigenetics as well as the milestone events since the proposal of the term 'epigenetics'. Moreover, we summarise the research methods of epigenetics and introduce four main general mechanisms of epigenetic modulation. Furthermore, we summarise epigenetic mechanisms in metabolic diseases and introduce the interaction between epigenetics and genetic or non-genetic factors. Finally, we introduce the clinical trials and applications of epigenetics in metabolic diseases.

MiRNA Profiling and Its Potential Roles in Rapid Growth of Velvet Antler in Gansu Red Deer (Cervus elaphus kansuensis)

A significant variety of cell growth factors are involved in the regulation of antler growth, and the fast proliferation and differentiation of various tissue cells occur during the yearly regeneration of deer antlers. The unique development process of velvet antlers has potential application value in many fields of biomedical research. Among them, the nature of cartilage tissue and the rapid growth and development process make deer antler a model for studying cartilage tissue development or rapid repair of damage. However, the molecular mechanisms underlying the rapid growth of antlers are still not well studied. MicroRNAs are ubiquitous in animals and have a wide range of biological functions. In this study, we used high-throughput sequencing technology to analyze the miRNA expression patterns of antler growth centers at three distinct growth phases, 30, 60, and 90 days following the abscission of the antler base, in order to determine the regulatory function of miRNA on the rapid growth of antlers. Then, we identified the miRNAs that were differentially expressed at various growth stages and annotated the functions of their target genes. The results showed that 4319, 4640, and 4520 miRNAs were found in antler growth centers during the three growth periods. To further identify the essential miRNAs that could regulate fast antler development, five differentially expressed miRNAs (DEMs) were screened, and the functions of their target genes were annotated. The results of KEGG pathway annotation revealed that the target genes of the five DEMs were significantly annotated to the "Wnt signaling pathway", "PI3K-Akt signaling pathway", "MAPK signaling pathway", and "TGF-β signaling pathway", which were associated with the rapid growth of velvet antlers. Therefore, the five chosen miRNAs, particularly ppy-miR-1, mmu-miR-200b-3p, and novel miR-94, may play crucial roles in rapid antler growth in summer.

Compromised osteogenic effect of exosomes internalized by senescent bone marrow stem cells via endocytoses involving clathrin, macropinocytosis and caveolae

Stem cell senescence leads to progressive functional declines and disrupts the physiological homeostasis of bone environment. Stem cell-derived exosomes are emerging as promising therapeutical approaches to treat diverse aging-related osseous diseases. Herein, a previously reported osteoinductive exosome (OI-exo) was applied as a therapeutic agent for bone repair in aging individuals and its internalization mechanisms in senescent bone marrow stem cells (BMSCs) were explored. The results demonstrated that OI-exos derived from young BMSCs could partially rescue the proliferation, osteogenic differentiation and alleviate aging phenotypes in vitro. OI-exo-delivered hierarchical mesoporous bioactive glass (MBG) scaffold effectively promote in vivo bone formation in aging rat cranial defect model. However, the osteogenic effects of OI-exo both in vitro and in vivo were compromised in senescent individuals and for aging BMSCs compared to younger ones. This study revealed that non-senescent BMSCs internalized exosomes exclusively via clathrin-mediated endocytosis, while senescent BMSCs additionally evoked macropinocytosis and caveolae-mediated endocytosis to mediate the internalization of exosomes. The alteration of endocytic manner of senescent BMSCs and the involvement of macropinocytosis might be responsible for the compromised effects of therapeutical exosomes. The phenomena discovered in this study could also be extended to other scenarios where drugs or treatments exerted compromised effects in aging individuals. The influence of endocytic manner, avoidance of macropinocytosis-related negative effects should be taken into considerations in future therapeutic design for aging populations.