TGF-β and BMP signaling in osteoblast differentiation and bone formation

Avermectin reduces bone mineralization via the TGF-β signaling pathway in zebrafish

Avermectin, a widely used insecticide, is primarily effective against animal parasites and insects. Given its extensive application in agriculture, a large amount of avermectin accumulates in natural water bodies. Studies have shown that avermectin has significant toxic effects on various organisms and on the nervous system, spine, and several other organs in humans. However, the effects of avermectin on bone development have not been reported yet. In this study, zebrafish embryos were treated with different concentrations of avermectin to explore the effects of avermectin on early bone development. The results showed that avermectin disturbed early bone development in zebrafish, caused abnormal craniofacial chondrogenesis, and reduced bone mineralization. Avermectin treatment significantly reduced mineralization in zebrafish scales and increased osteoclast activity. Real-time quantitative PCR results showed that avermectin decreased the expression of genes related to osteogenesis and transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signaling pathways. The TGF-β inhibitor SB431542 rescued avermectin-induced bone mineralization and osteogenesis related gene expression in zebrafish during early development. Thus, this study provides insight into the mechanism of damage caused by avermectin on bone development, thus helping demonstrate its toxicity.

Osteoinductive and Osteogenic Capacity of Freeze-Dried Bovine Bone Compared to Deproteinized Bovine Bone Mineral Scaffold in Human Umbilical Cord Mesenchymal Stem Cell Culture: An In Vitro Study

OBJECTIVE

 Freeze-dried bovine bone scaffold (FDBB) or decellularized FDBB (dc-FDBB) was developed as an ideal scaffold with osteoinductive properties. This research aims to compare the osteoinductive properties marked by the expression of runt-related transcription factor-2 (RUNX2) and Osterix (OSX) and the osteogenic capacity of these scaffolds imbued with human umbilical cord mesenchymal stem cells (hUCMSCs).

MATERIALS AND METHODS

 This study was performed in five experimental groups: a negative control group (C-) of hUCMSCs with a normal growth medium, a positive control group (C + ) of hUCMSCs with an osteogenic medium, experimental group 1 (E1) with an FDBB conditioned medium (CM), and experimental group 2 (E2) with a dc-FDBB-CM, and a third experimental group (E3) consisting of a DBBM-CM. Alizarin red staining was performed to qualitatively assess osteoinductive capacity. RUNX2 and OSX expression was quantified using real-time quantification polymerase chain reaction with two replications on day six (D6) and day 12 (D12) as fold changes.

RESULTS

 This experiment revealed that hUCMSCs were positively expressed by CD73, CD90, and CD105 but were not expressed by CD34. Alizarin red staining showed that E1 had the most calcium deposition on D6 and D12, followed by E3 and then E2 The RUNX2 and OSX expression was higher in E1 but this difference was not significant. The OSX expression in E1,E2,E3 was lower on D12 and C+ of OSX had the highest expression. There was a significant difference of fold change measured between all groups (p < 0.05), and there was no significant difference between any of the groups treated with OSX and RUNX2 on D6 and D12.

CONCLUSION

 FDBB osteoinduction and osteogenic capacity were higher when compared with DBBM and dc-FDBB.

Ataluren prevented bone loss induced by ovariectomy and aging in mice through the BMP-SMAD signaling pathway

Both estrogen deficiency and aging may lead to osteoporosis. Developing novel drugs for treating osteoporosis is a popular research direction. We screened several potential therapeutic agents through a new deep learning-based efficacy prediction system (DLEPS) using transcriptional profiles for osteoporosis. DLEPS screening led to a potential novel drug examinee, ataluren, for treating osteoporosis. Ataluren significantly reversed bone loss in ovariectomized mice. Next, ataluren significantly increased human bone marrow-derived mesenchymal stem cell (hBMMSC) osteogenic differentiation without cytotoxicity, indicated by the high expression index of osteogenic differentiation genes (OCN , BGLAP, ALP, COL1A, BMP2, RUNX2). Mechanistically, ataluren exerted its function through the BMP-SMAD pathway. Furthermore, it activated SMAD phosphorylation but osteogenic differentiation was attenuated by BMP2-SMAD inhibitors or small interfering RNA of BMP2. Finally, ataluren significantly reversed bone loss in aged mice. In summary, our findings suggest that the DLEPS-screened ataluren may be a therapeutic agent against osteoporosis by aiding hBMMSC osteogenic differentiation.

Indications and surgical technique for distraction osteogenesis of the alveolar bone for augmentation prior to insertion of dental implants

When bone is limited, short, ultra-short, or narrow implants help to restore oral rehabilitation with an acceptable long-term outcome. This becomes more difficult with severe vertical bone loss. Guided bone regeneration, onlay block transplantation, or sandwich osteotomy have been established to build up these defects. The alternative to the alveolar distraction osteogenesis (ADO) has only been established in some centers, with a standardized protocol. On the one hand, ADO is a biological procedure that allows almost a "restitutio ad integrum" when building up hard and soft tissue. On the other hand, there are clear indications, limitations, and complications of the procedure in the literature. In addition to the literature, concept of Tissue Regeneration by Alveolar Callusdistraction Cologne (TRACC), which has been practiced successfully for over two decades, will be presented for different indications.

MicroRNA-26 and Related Osteogenic Target Genes Could Play Pivotal Roles in Photobiomodulation and Adipose-Derived Stem Cells-Based Healing of Critical Size Foot Defects in the Rat Model

Objective: In this study, we aimed to explore the role of MicroRNA-26 in photobiomodulation (PBM)- and adipose-derived stem cell (ADS)-based healing of critical-sized foot fractures in a rat model. Background: PBM and ADS treatments are relatively invasive methods for treating bone defects. Specific and oriented cellular and molecular functions can be induced by applying an appropriate type of PBM and ADS treatment. Methods: A critical size foot defect (CSFD) is induced in femoral bones of 24 rats. Then, a human demineralized bone matrix scaffold (hDBMS) was engrafted into all CSFDs. The rats were randomly allocated into four groups (n = 6): (1) control (hDBMS); (2) hDBMS+human ADSs (hADSs), hADSs engrafted into CSFDs; (3) hDBMS+PBM, CSFD exposed to PBM (810 nm wavelength, 1.2 J/cm2 energy density); and (4) hDBMS+(hADSs+PBM), hADSs implanted into the CSFD and then exposed to PBM. At 42 days after CSFD induction, the rats were killed, and the left CSFD was removed for mechanical compression tests and the right CSFD was removed for molecular and histological studies. Results: The results indicate that miRNA-26a, BMP, SMAD, RUNX, and OSTREX had higher expression in the treated groups than in the control group. Further, the biomechanical and histological properties of CSFDs in treated groups were improved compared with the control group. Correlation tests revealed a positive relationship between microRNA and improved biomechanical and cellular parameters of CSFDs in the rat model. Conclusions: We concluded that the MicroRNA-26 signaling pathway probably plays a significant role in the hADS-, PBM-, and hADS+PBM-based healing of CSFDs in rats. Clinical Trial Registration number: IR.SBMU.MSP.REC.1398.980.

Transcriptome analysis of osteogenic differentiation of human maxillary sinus mesenchymal stem cells using RNA-Seq

Recent studies have demonstrated that human maxillary sinus mesenchymal stem cells (hMSMSCs) have osteogenic potential and can be osteogenically induced. Here, we investigated pivotal molecular functions and candidates that contribute to the osteogenic differentiation of hMSMSCs. Human maxillary sinus membranes were harvested from 3 patients with jaw deformities. hMSMSCs from human maxillary sinus membranes were osteogenically induced for 0 or 21 days. Subsequently, their functional profiles were analysed by RNA sequencing and validated by quantitative PCR. Compared with control hMSMSCs, osteogenically induced hMSMSCs showed (1) osteogenic differentiation phenotype, as evidenced by the cell nodes, alizarin red staining, osteogenesis-related protein, and RNA expression; (2) accelerated osteogenic process of ossification and calcium signalling, as demonstrated by Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway; (3) enriched osteogenesis gene expression of SMOC2, OMD, IGF1, JUNB, BMP5, ADRA1A, and IGF2, which was validated by quantitative PCR. Based on by these results, we demonstrated that accelerated ossification process, calcium signalling, and upregulation of SMOC2, OMD, IGF1, JUNB, BMP5, ADRA1A and IGF2, may contribute to the osteogenic differentiation of hMSMSCs.

The odontoblastic differentiation of dental mesenchymal stem cells: molecular regulation mechanism and related genetic syndromes

Dental mesenchymal stem cells (DMSCs) are multipotent progenitor cells that can differentiate into multiple lineages including odontoblasts, osteoblasts, chondrocytes, neural cells, myocytes, cardiomyocytes, adipocytes, endothelial cells, melanocytes, and hepatocytes. Odontoblastic differentiation of DMSCs is pivotal in dentinogenesis, a delicate and dynamic process regulated at the molecular level by signaling pathways, transcription factors, and posttranscriptional and epigenetic regulation. Mutations or dysregulation of related genes may contribute to genetic diseases with dentin defects caused by impaired odontoblastic differentiation, including tricho-dento-osseous (TDO) syndrome, X-linked hypophosphatemic rickets (XLH), Raine syndrome (RS), hypophosphatasia (HPP), Schimke immuno-osseous dysplasia (SIOD), and Elsahy-Waters syndrome (EWS). Herein, recent progress in the molecular regulation of the odontoblastic differentiation of DMSCs is summarized. In addition, genetic syndromes associated with disorders of odontoblastic differentiation of DMSCs are discussed. An improved understanding of the molecular regulation and related genetic syndromes may help clinicians better understand the etiology and pathogenesis of dentin lesions in systematic diseases and identify novel treatment targets.

Distal tibial trabecular morphometry in a Sprague Dawley rat model of fetal alcohol syndrome: a micro focus X-ray computed tomography case-control study

Introduction

intrauterine alcohol exposure has adverse health effects on the offspring, which may result in fetal Alcohol Spectrum Disorders (FASD). The neurological and craniofacial aspects have been well studied; however, long bones have received limited attention despite the short stature reported in FASD children.

Methods

time-mated (n=13) pregnant Sprague Dawley dams were assigned to either the ethanol (n=5), saline control (n=5) or untreated group (n=3) which received no treatment. The ethanol and saline control dams were treated with 0.015ml/g of 25.2% ethanol or 0.9% saline, respectively. Treatment was for the first 19 days of gestation. Two pups from each dam were used and terminated at 21 days of age. Paired tibiae were harvested. Each bone was scanned using a Nikon XTH 225L 3D-μCT to investigate trabeculae morphometry.

Results

the ethanol group had less bone to total volume (BT/TV), thinnest trabeculae (TbTh) which were less spaced (TbSp) compared to the controls. However, number of trabecular (TbN) remained unaffected in all three groups. Tibial length was similar in all three groups; however, the distal metaphysis volume was smallest in the ethanol group. Logistic regression showed that the distal medullary canal area and trabecular separation were the main parameters affected the most in gestational alcohol. The negative correlation of trabecular thickness and spacing in the ethanol group may be a contributor to bone weakness.

Conclusion

gestational alcohol exposure affects bone internal morphology in addition to the bone size. Overall, this study supports the findings of clinical observation of small stature in FAS children.

A periosteum-derived cell line to study the role of BMP/TGFβ signaling in periosteal cell behavior and function

The periosteum is a thin tissue surrounding each skeletal element that contains stem and progenitor cells involved in bone development, postnatal appositional bone growth, load-induced bone formation, and fracture repair. BMP and TGFβ signaling are important for periosteal activity and periosteal cell behavior, but thorough examination of the influence of these pathways on specific cell populations resident in the periosteum is lacking due to limitations associated with primary periosteal cell isolations and in vitro experiments. Here we describe the generation of a novel periosteum-derived clonal cell (PDC) line from postnatal day 14 mice and use it to examine periosteal cell behavior in vitro. PDCs exhibit key characteristics of periosteal cells observed during skeletal development, maintenance, and bone repair. Specifically, PDCs express established periosteal markers, can be expanded in culture, demonstrate the ability to differentiate into chondrocytes, osteoblasts, and adipocytes, and exhibit an osteogenic response to physical stimulation. PDCs also engage in BMP and/or TGFβ signaling when treated with the activating ligands BMP2 and TGFβ-1, and in response to mechanical stimulation via fluid shear. We believe that this PDC line will be useful for large-scale, long-term experiments that were not feasible when using primary periosteal cells. Anticipated future uses include advancing our understanding of the signaling interactions that occur during appositional bone growth and fracture repair and developing drug screening platforms to discover novel growth and fracture healing factors.

Identification of Bone Morphometric Protein-Related Hub Genes and Construction of a Transcriptional Regulatory Network in Patients With Ossification of the Ligamentum Flavum

STUDY DESIGN

Basic science laboratory study.

OBJECTIVE

To identify hub genes related to bone morphogenetic proteins (BMPs) in the ossification of the ligamentum flavum (OLF) and analyze their functional characteristics.

SUMMARY OF BACKGROUND DATA

The exact etiology and pathologic mechanism of OLF remain unclear. BMPs are pleiotropic osteoinductive proteins that may play a critical role in this condition.

MATERIALS AND METHODS

The GSE106253 and GSE106256 data sets were downloaded from the Gene Expression Omnibus database. The messenger RNA (mRNA) and long noncoding RNA expression profiles were obtained from GSE106253. The microRNA expression profiles were obtained from GSE106256. Differentially expressed genes were identified between OLF and non-OLF groups and then intersected with BMP-related genes to obtain differentially expressed BMP-related genes. The least absolute shrinkage selection operator and support vector machine recursive feature elimination were used to screen hub genes. Furthermore, a competing endogenous RNA network was constructed to explain the expression regulation of the hub genes in OLF. Finally, the protein and mRNA expression levels of the hub genes were verified using Western blot and real-time polymerase chain reaction, respectively.

RESULTS

We identified 671 Differentially expressed genes and 32 differentially expressed BMP-related genes. Hub genes ADIPOQ , SCD , SCX , RPS18 , WDR82 , and SPON1 , identified through the least absolute shrinkage selection operator and support vector machine recursive feature elimination analyses, showed high diagnostic values for OLF. Furthermore, the competing endogenous RNA network revealed the regulatory mechanisms of the hub genes. Real-time polymerase chain reaction showed that the mRNA expression of the hub genes was significantly downregulated in the OLF group compared with the non-OLF group. Western blot showed that the protein levels of ADIPOQ, SCD, WDR82 , and SPON1 were significantly downregulated, whereas those of SCX and RPS18 were significantly upregulated in the OLF group compared with the non-OLF group.

CONCLUSION

This study is the first to identify BMP-related genes in OLF pathogenesis through bioinformatics analysis. ADIPOQ , SCD , SCX , RPS18 , WDR82 , and SPON1 were identified as hub genes for OLF. The identified genes may serve as potential therapeutic targets for treating patients with OLF.

Prostate cancer and bone: clinical presentation and molecular mechanisms

Prostate cancer (PCa) is an increasingly prevalent health problem in the developed world. Effective treatment options exist for localized PCa, but metastatic PCa has fewer treatment options and shorter patient survival. PCa and bone health are strongly entwined, as PCa commonly metastasizes to the skeleton. Since androgen receptor signaling drives PCa growth, androgen-deprivation therapy whose sequelae reduce bone strength constitutes the foundation of advanced PCa treatment. The homeostatic process of bone remodeling - produced by concerted actions of bone-building osteoblasts, bone-resorbing osteoclasts, and regulatory osteocytes - may also be subverted by PCa to promote metastatic growth. Mechanisms driving skeletal development and homeostasis, such as regional hypoxia or matrix-embedded growth factors, may be subjugated by bone metastatic PCa. In this way, the biology that sustains bone is integrated into adaptive mechanisms for the growth and survival of PCa in bone. Skeletally metastatic PCa is difficult to investigate due to the entwined nature of bone biology and cancer biology. Herein, we survey PCa from origin, presentation, and clinical treatment to bone composition and structure and molecular mediators of PCa metastasis to bone. Our intent is to quickly yet effectively reduce barriers to team science across multiple disciplines that focuses on PCa and metastatic bone disease. We also introduce concepts of tissue engineering as a novel perspective to model, capture, and study complex cancer-microenvironment interactions.

Bioprinted constructs that simulate nerve-bone crosstalk to improve microenvironment for bone repair

Crosstalk between nerves and bone is essential for bone repair, for which Schwann cells (SCs) are crucial in the regulation of the microenvironment. Considering that exosomes are critical paracrine mediators for intercellular communication that exert important effects in tissue repair, the aim of this study is to confirm the function and molecular mechanisms of Schwann cell-derived exosomes (SC-exos) on bone regeneration and to propose engineered constructs that simulate SC-mediated nerve-bone crosstalk. SCs promoted the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) through exosomes. Subsequent molecular mechanism studies demonstrated that SC-exos promoted BMSC osteogenesis by regulating the TGF-β signaling pathway via let-7c-5p. Interestingly, SC-exos promoted the migration and tube formation performance of endothelial progenitor cells. Furthermore, the SC-exos@G/S constructs were developed by bioprinting technology that simulated SC-mediated nerve-bone crosstalk and improved the bone regeneration microenvironment by releasing SC-exos, exerting the regulatory effect of SCs in the microenvironment to promote innervation, vascularization, and osteogenesis and thus effectively improving bone repair in a cranial defect model. This study demonstrates the important role and underlying mechanism of SCs in regulating bone regeneration through SC-exos and provides a new engineered strategy for bone repair.

Eicosapentaenoic acid supplementation modulates the osteoblast/osteoclast balance in inflammatory environments and protects against estrogen deficiency-induced bone loss in mice

BACKGROUND

An imbalance of osteoblasts (OBs) and osteoclasts (OCs) in a chronic inflammatory microenvironment is an important pathological factor leading to osteoporosis. Eicosapentaenoic acid (EPA) has been shown to suppress inflammation in macrophages and adipocytes. However, the effect of EPA on OBs and OCs has yet to be fully elucidated.

AIMS

We explored the roles of EPA in the differentiation of OBs and OCs, as well as the coupling between OBs and OCs in an inflammatory microenvironment. The effects of EPA on estrogen deficiency-induced osteoporosis were also evaluated.

METHODS

Mouse bone marrow mesenchymal stem cells (mBMSCs) and mouse bone marrow-derived macrophages (mBMMs) were used for in vitro OBs and OCs differentiation. TNF-α was used to create an inflammatory microenvironment. We examined the effects of EPA on osteoblastogenesis in the absence or presence of TNF-α and collect OBs' culture medium as the conditioned medium (CM). Then we examined the effects of EPA and CM on RANKL-induced osteoclastogenesis. The in vivo effects of EPA were determined using an ovariectomized (OVX) mouse model treated with EPA or vehicle.

RESULTS

High-dose EPA was shown to promote osteoblastogenesis in an inflammatory environment in vitro, as well as upregulate expression of OBs-specific proteins and genes. ARS and ALP staining also showed that high-dose EPA-treated groups restored mBMSCs' impaired osteogenic capacity caused by TNFa. Mechanistically, EPA suppressed the NF-κB pathway activated by TNF-α in mBMSCs and rescued TNF-α-mediated inhibition of osteoblastogenesis. EPA was also shown to inhibit expression of RANKL and decrease the RANKL/OPG ratio in OBs in an inflammatory environment. CM from TNF-α-stimulated OBs promoted osteoclastogenesis of mBMMs; EPA-treated CM prevented this. In the OVX mouse model, EPA supplementation prevented bone loss in an estrogen deficiency-induced inflammatory environment.

CONCLUSIONS

EPA was demonstrated for the first time to restore mBMSCs' impaired osteogenic capacity caused by TNFa-induced inflammation and rescue the OBs/OCs balance via regulation of RANKL and OPG expression in OBs. EPA showed a remarkable ability to prevent bone loss in OVX mice, suggesting a potential application of EPA in postmenopausal osteoporosis.

Brazilian Society of Otology task force - Otosclerosis: evaluation and treatment

OBJECTIVES

To review and provide evidence-based recommendations for the diagnosis and treatment of otosclerosis.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on otosclerosis were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: 1) Diagnosis - audiologic and radiologic; 2) Treatment - hearing AIDS, pharmacological therapy, stapes surgery, and implantable devices - bone-anchored devices, active middle ear implants, and Cochlear Implants (CI).

CONCLUSIONS

The pathophysiology of otosclerosis has not yet been fully elucidated, but environmental factors and unidentified genes are likely to play a significant role in it. Women with otosclerosis are not at increased risk of worsening clinical condition due to the use of contraceptives or during pregnancy. Drug treatment has shown little benefit. If the patient does not want to undergo stapedotomy, the use of hearing aids is well indicated. Implantable systems should be indicated only in rare cases, and the CI should be indicated in cases of profound deafness.

Osteogenic induction of asiatic acid derivatives in human periodontal ligament stem cells

Asiatic acid (AA) and asiaticoside, pentacyclic triterpenoid compounds derived from Centella asiatica, are known for their biological effects in promoting type I collagen synthesis and inducing osteogenesis of stem cells. However, their applications in regenerative medicine are limited due to their low potency and poor aqueous solubility. This work aimed to evaluate the osteogenic induction activity of AA derivatives in human periodontal ligament stem cells (hPDLSCs) in vitro. Four compounds were synthesised, namely 501, 502, 503, and 506. AA was used as the control. The 502 exhibited low water solubility, while the 506 compound showed the highest. The cytotoxicity analysis demonstrated that 503 caused significant deterioration in cell viability, while other derivatives showed no harmful effect on hPDLSCs. The dimethyl aminopropyl amine derivative of AA, compound 506, demonstrated a relatively high potency in inducing osteogenic differentiation. An elevated mRNA expression of osteogenic-related genes, BMP2, WNT3A, ALP, OSX and IBSP was observed with 506. Additionally, the expression of BMP-2 protein was enhanced with increasing dose of 506, and the effect was pronounced when the Erk signalling molecule was inhibited. The 506 derivative was proposed for the promotion of osteogenic differentiation in hPDLSCs by upregulating BMP2 via the Erk signalling pathway. The 506 molecule showed promise in bone tissue regeneration.

A Review: Methodologies to Promote the Differentiation of Mesenchymal Stem Cells for the Regeneration of Intervertebral Disc Cells Following Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration (IDD), a highly prevalent pathological condition worldwide, is widely associated with back pain. Treatments available compensate for the impaired function of the degenerated IVD but typically have incomplete resolutions because of their adverse complications. Therefore, fundamental regenerative treatments need exploration. Mesenchymal stem cell (MSC) therapy has been recognized as a mainstream research objective by the World Health Organization and was consequently studied by various research groups. Implanted MSCs exert anti-inflammatory, anti-apoptotic, and anti-pyroptotic effects and promote extracellular component production, as well as differentiation into IVD cells themselves. Hence, the ultimate goal of MSC therapy is to recover IVD cells and consequently regenerate the extracellular matrix of degenerated IVDs. Notably, in addition to MSC implantation, healthy nucleus pulposus (NP) cells (NPCs) have been implanted to regenerate NP, which is currently undergoing clinical trials. NPC-derived exosomes have been investigated for their ability to differentiate MSCs from NPC-like phenotypes. A stable and economical source of IVD cells may include allogeneic MSCs from the cell bank for differentiation into IVD cells. Therefore, multiple alternative therapeutic options should be considered if a refined protocol for the differentiation of MSCs into IVD cells is established. In this study, we comprehensively reviewed the molecules, scaffolds, and environmental factors that facilitate the differentiation of MSCs into IVD cells for regenerative therapies for IDD.

Effect of Mesenchymal Stem Cells Overexpressing BMP-9 Primed with Hypoxia on BMP Targets, Osteoblast Differentiation and Bone Repair

Bone formation is driven by many signaling molecules including bone morphogenetic protein 9 (BMP-9) and hypoxia-inducible factor 1-alpha (HIF-1α). We demonstrated that cell therapy using mesenchymal stem cells (MSCs) overexpressing BMP-9 (MSCs+BMP-9) enhances bone formation in calvarial defects. Here, the effect of hypoxia on BMP components and targets of MSCs+BMP-9 and of these hypoxia-primed cells on osteoblast differentiation and bone repair was evaluated. Hypoxia was induced with cobalt chloride (CoCl2) in MSCs+BMP-9, and the expression of BMP components and targets was evaluated. The paracrine effects of hypoxia-primed MSCs+BMP-9 on cell viability and migration and osteoblast differentiation were evaluated using conditioned medium. The bone formation induced by hypoxia-primed MSCs+BMP-9 directly injected into rat calvarial defects was also evaluated. The results demonstrated that hypoxia regulated BMP components and targets without affecting BMP-9 amount and that the conditioned medium generated under hypoxia favored cell migration and osteoblast differentiation. Hypoxia-primed MSCs+BMP-9 did not increase bone repair compared with control MSCs+BMP-9. Thus, despite the lack of effect of hypoxia on bone formation, the enhancement of cell migration and osteoblast differentiation opens windows for further investigations on approaches to modulate the BMP-9-HIF-1α circuit in the context of cell-based therapies to induce bone regeneration.

Advanced Skeletal Ossification Is Associated with Genetic Variants in Chronologically Young Beef Heifers

Osteogenesis is a developmental process critical for structural support and the establishment of a dynamic reservoir for calcium and phosphorus. Changes in livestock breeding over the past 100 years have resulted in earlier bone development and increased physical size of cattle. Advanced skeletal maturity is now commonly observed at harvest, with heifers displaying more mature bone than is expected at 30 months of age (MOA). We surmise that selection for growth traits and earlier reproductive maturity resulted in co-selection for accelerated skeletal ossification. This study examines the relationship of single nucleotide polymorphisms (SNPs) in 793 beef heifers under 30 MOA with USDA-graded skeletal maturity phenotypes (A-, B-, C- skeletal maturity). Further, the estrogen content of FDA-approved hormonal implants provided to heifers prior to harvest was evaluated in association with the identified SNPs and maturities. Association tests were performed, and the impact of the implants were evaluated as covariates against genotypes using a logistic regression model. SNPs from the ESR1, ALPL, PPARGC1B, SORCS1 genes, and SNPs near KLF14, ANKRD61, USP42, H1C1, OVCA2, microRNA mir-29a were determined to be associated with the advanced skeletal ossification phenotype in heifers. Higher dosage estrogen implants increased skeletal maturity in heifers with certain SNP genotypes.

Functionalized Decellularized Bone Matrix Promotes Bone Regeneration by Releasing Osteogenic Peptides

The decellularized bone matrix (DCB) provides a promising bone substitute for the treatment of bone defects because of its similar biochemical, biophysical, and mechanical properties to normal bone tissue. However, the decellularized procedure also greatly reduced its osteogenic induction activity. In this study, peptides derived from the knuckle epitope of bone morphogenetic protein-2 were incorporated into the thermo-sensitive hydrogel poloxamer 407, and the peptide-loaded hydrogel was then filled into the pores of DCB to construct a functionalized scaffold with enhanced osteogenesis. In vitro studies have shown that the functionalized DCB scaffold possessed appropriate mechanical properties and biocompatibility and exhibited a sustained release profile of osteogenic peptide. These performances critically facilitated cell proliferation and cell spreading of bone marrow mesenchymal stem cells and upregulated the expression of osteogenic-related genes by activating the Smad/Runx2 signaling pathway, thereby promoting osteogenic differentiation and extracellular matrix mineralization. Further in vivo studies demonstrated that the functionalized DCB scaffold accelerated the repair of critical radial defects in rabbits without inducing excessive graft-related inflammatory responses. These results suggest a clinically meaningful strategy for the treatment of large segmental bone defects, and the prepared osteogenic peptide modified composite DCB scaffold has great application potential for bone regeneration.

The healing capacity and osteogenesis pattern of demineralized dentin matrix (DDM)-fibrin glue (FG) compound

Demineralized dentin matrix (DDM) is an osteoconductive and osteoinductive material that has been successfully used in sinus floor augmentation and alveolar ridge augmentation in clinical applications. It releases bone morphogenetic proteins (BMPs) and other growth factors, making DDM a suitable grafting material. However, the granular particle of DDM makes it difficult to anchor into the bone defect area. The aim of this study was to investigate the biological effects and osteoinductivity of the combination of DDM and Fibrin Glue (FG) at an optimal ratio on bone healing from a critical bone defect in an animal model. The mouse osteoblastic cell line (MC3T3-E1) was co-cultured with various ratios of DDM and FG to examine their effects on osteoblast proliferation and differentiation, as indicated by alkaline phosphatase (ALP) activity, osteocalcin (OC) production and mineralized nodules formation. The optimal ratio was then chosen for further study with a rabbit calvarial defective model, in which they were implanted with DDM or DDM-FG1 (1 g: 0.1 ml) and DDM-FG2 (1 g: 0.5 ml) compounds, or left blank for 2, 4, 8 and 12 weeks to investigate soft tissue and new bone regeneration. Micro-CT and histology analysis were used to evaluate the total grafting properties according to the different healing periods. The result from in vitro studies demonstrated that the ratio of 1:0.1 induced more ALP activity and mineralized nodules, while the ratio of 1: 0.5 (DDM-FG combined) induced more osteocalcin (OC) at specific time points. In the animal model, the 3D new bone volume in all DDM-FG treatment groups was significantly greater than that in the blank group at 2, 4, 8 and 12 weeks. Furthermore, the new bone volume was greater in DDM-FG2 when compared to the other groups during the early weeks of the healing period. In histological analysis, clusters of osteoblasts were formed adjacent to the DDM particles, and newly formed bone was observed in all groups, suggesting an osteoinductive property of DDM. Moreover, the greater new collagen synthesis observed at 4 weeks suggested that early bone healing was induced in the DDM-FG2 group. This study demonstrated that at an optimal ratio, the DDM-FG compound enhances osteogenic activities and bone regeneration.

The Bone Microenvironment Soil in Prostate Cancer Metastasis: An miRNA Approach

Bone metastatic prostate cancer (PCa) is associated with a high risk of mortality. Changes in the expression pattern of miRNAs seem to be related to early aspects of prostate cancer, as well as its establishment and proliferation, including the necessary steps for metastasis. Here we compiled, for the first time, the important roles of miRNAs in the development, diagnosis, and treatment of bone metastasis, focusing on recent in vivo and in vitro studies. PCa exosomes are proven to promote metastasis-related events, such as osteoblast and osteoclast differentiation and proliferation. Aberrant miRNA expression in PCa may induce abnormal bone remodeling and support tumor development. Furthermore, miRNAs are capable of binding to multiple mRNA targets, a dynamic property that can be harnessed for the development of treatment tools, such as antagomiRs and miRNA mimics, which have emerged as promising candidates in PCa treatment. Finally, miRNAs may serve as noninvasive biomarkers, as they can be detected in tissue and bodily fluids, are highly stable, and show differential expression between nonmetastatic PCa and bone metastatic samples. Taken together, the findings underscore the importance of miRNA expression profiles and miRNA-based tools as rational technologies to increase the quality of life and longevity of patients.

TGF-β promotes the proliferation and osteogenic differentiation of dental pulp stem cells a systematic review and meta-analysis

BACKGROUND

Dental pulp stem cells (DPSCs) are adult stem cells with multi-directional differentiation potential derived from ectoderm. Vitro experiments have shown that adding cytokines can help DPSCs to be transformed from multipotent stem cells to osteoblasts. TGF-β has been proved to have an effect on the proliferation and mineralization of bone tissue, but its effect on the osteogenesis and proliferation of dental pulp stem cells is still uncertain. We aim to determine the effect of TGF-β on the osteogenesis and proliferation of dental pulp stem cells.

METHODS

We have identified studies from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and China national knowledge infrastructure (CNKI) for studies interested in TGF-β and proliferation and differentiation of dental pulp stem cells in the following indicators: A490 (an index for evaluating cell proliferation), bone sialoprotein (BSP), Col plasmid-1 (Col-1), osteocalcin (OCN), runt-related transcription factor 2 (Runx-2); and the number of mineralized nodules. Any language restrictions were rejected. Furthermore, we drew a forest plot for each outcome. We conducted a sensitivity analysis, data analysis, heterogeneity, and publication bias test. We evaluate the quality of each study under the guidance of Cochrane's tool for quality assessment.

RESULTS

The pooled data showed that TGF-β could promote the proliferation and ossification of dental pulp stem cells. All the included results support this conclusion except for the number of mineralized nodules: TGF-β increases the A490 index (SMD 3.11, 95% CI [0.54-5.69]), promotes the production of BSP (SMD 3.11, 95% CI [0.81-6.77]), promotes the expression of Col-1 (SMD 4.71, 95% CI [1.25-8.16]) and Runx-2 (SMD 3.37, 95% CI [- 0.63 to 7.36]), increases the content of OCN (SMD 4.32, 95% CI [1.20-7.44]) in dental pulp, and has no significant effect on the number of mineralized nodules (SMD 3.87, 95% CI [- 1.76 to 9.51]) in dental pulp stem cells.

CONCLUSIONS

TGF-β promotes the proliferation and osteogenesis of dental pulp stem cells.

The Relationship between Renin-Angiotensin-Aldosterone System (RAAS) Activity, Osteoporosis and Estrogen Deficiency in Type 2 Diabetes

Type 2 diabetes (T2D) is associated with a plethora of comorbidities, including osteoporosis, which occurs due to an imbalance between bone resorption and formation. Numerous mechanisms have been explored to understand this association, including the renin-angiotensin-aldosterone system (RAAS). An upregulated RAAS has been positively correlated with T2D and estrogen deficiency in comorbidities such as osteoporosis in humans and experimental studies. Therefore, research has focused on these associations in order to find ways to improve glucose handling, osteoporosis and the downstream effects of estrogen deficiency. Upregulation of RAAS may alter the bone microenvironment by altering the bone marrow inflammatory status by shifting the osteoprotegerin (OPG)/nuclear factor kappa-Β ligand (RANKL) ratio. The angiotensin-converting-enzyme/angiotensin II/Angiotensin II type 1 receptor (ACE/Ang II/AT1R) has been evidenced to promote osteoclastogenesis and decrease osteoblast formation and differentiation. ACE/Ang II/AT1R inhibits the wingless-related integration site (Wnt)/β-catenin pathway, which is integral in bone formation. While a lot of literature exists on the effects of RAAS and osteoporosis on T2D, the work is yet to be consolidated. Therefore, this review looks at RAAS activity in relation to osteoporosis and T2D. This review also highlights the relationship between RAAS activity, osteoporosis and estrogen deficiency in T2D.

Icariin promotes osteogenic differentiation by upregulating alpha-enolase expression

Osteogenic differentiation is a crucial biological process for maintaining bone remodelling. Aerobic glycolysis is the main source of energy for osteogenic differentiation. Alpha-enolase (Eno1), a glycolytic enzyme, is a therapeutic target for numerous diseases. Icariin, a principal active component of the traditional Chinese medicine Epimedium grandiflorum, can stimulate osteogenic differentiation. Here, we aimed to determine if icariin promotes osteogenic differentiation via Eno1. Icariin (1 μM) significantly promoted osteogenic differentiation of MC3T3-E1 cells. Icariin upregulated Eno1 protein and gene expressions during osteogenic differentiation. Moreover, ENOblock, a specific inhibitor of Eno1, markedly inhibited icariin-induced osteogenic differentiation. Futhermore, western blot assay showed that Eno1 might mediate osteogenic differentiation through the BMP/Smad4 signalling pathway. Collectively, Eno1 could be a promising drug target for icariin to regulate osteogenic differentiation.

The Inflammatory Contribution of B-Lymphocytes and Neutrophils in Progression to Osteoporosis

Osteoporosis is a bone disease characterized by structural deterioration and low bone mass, leading to fractures and significant health complications. In this review, we summarize the mechanisms by which B-lymphocytes and neutrophils contribute to the development of osteoporosis and potential therapeutics targeting these immune mediators to reduce the proinflammatory milieu. B-lymphocytes-typically appreciated for their canonical role in adaptive, humoral immunity-have emerged as critical regulators of bone remodeling. B-lymphocytes communicate with osteoclasts and osteoblasts through various cytokines, including IL-7, RANK, and OPG. In inflammatory conditions, B-lymphocytes promote osteoclast activation and differentiation. However, B-lymphocytes also possess immunomodulatory properties, with regulatory B-lymphocytes (Bregs) secreting TGF-β1 to restrain pathogenic osteoclastogenesis. Neutrophils, the body's most prevalent leukocyte, also contribute to the proinflammatory environment that leads to osteoporotic bone remodeling. In aged individuals, neutrophils display reduced chemotaxis, phagocytosis, and apoptosis. Understanding the delicate interplay between B-lymphocytes and neutrophils in the context of impaired bone metabolism is crucial for targeted therapies for osteoporosis.

Chondrocyte Homeostasis and Differentiation: Transcriptional Control and Signaling in Healthy and Osteoarthritic Conditions

Chondrocytes are the main cell type in articular cartilage. They are embedded in an avascular, abundant, and specialized extracellular matrix (ECM). Chondrocytes are responsible for the synthesis and turnover of the ECM, in which the major macromolecular components are collagen, proteoglycans, and non-collagen proteins. The crosstalk between chondrocytes and the ECM plays several relevant roles in the regulation of cell phenotype. Chondrocytes live in an avascular environment in healthy cartilage with a low oxygen supply. Although chondrocytes are adapted to anaerobic conditions, many of their metabolic functions are oxygen-dependent, and most cartilage oxygen is supplied by the synovial fluid. This review focuses on the transcription control and signaling responsible for chondrocyte differentiation, homeostasis, senescence, and cell death and the changes that occur in osteoarthritis. The effects of chondroitin sulfate and other molecules as anti-inflammatory agents are also approached and analyzed.

Huangqi decoction ameliorates kidney injury in db/db mice by regulating the BMP/Smad signaling pathway

PURPOSE

This study aims to investigate the mechanism underlying the beneficial effects of Huangqi decoction (HQD) on Diabetic kidney disease (DKD) in diabetic db/db mice.

METHODS

Eight-week-old male diabetic db/db mice were randomly divided into four groups: Model (1% CMC), HQD-L (0.12 g/kg), HQD-M (0.36 g/kg), and HQD-H (1.08 g/kg) groups. Non-diabetic db/m mice were served as the control group. These mice received HQD treatment for 8 weeks. After treatment, the kidney function, histopathology, micro-assay, and protein expression levels were assessed.

RESULTS

HQD treatment improved the albumin/creatine ratio (ACR) and 24 h urinary albumin excretion, prevented the pathological phenotypes of increased glomerular volume, widened mesangial areas, the of mesangial matrix proliferation, foot process effacement, decreased nephrin expression and reduced number of podocytes. Expression profiling analysis revealed global transcriptional changes that predicted related functions, diseases and pathways. HQD treatment activated protein expressions of BMP2, BMP7, BMPR2, and active-Rap1, while inhibiting Smad1 and phospho-ERK. In addition, HQD was associated with improvements in lipid deposition in the kidneys of db/db mice.

CONCLUSION

HQD ameliorated the progression of DKD in db/db mice by regulating BMP transcription and downstream targets, inhibiting the phosphorylation of ERK and the expression of Smad1, promoting Rap1 binding to GTP, and regulating the lipid metabolism. These findings provide a potential therapeutic approach for treating DKD.

Macrophages-bone marrow mesenchymal stem cells crosstalk in bone healing

Bone healing is associated with many orthopedic conditions, including fractures and osteonecrosis, arthritis, metabolic bone disease, tumors and periprosthetic particle-associated osteolysis. How to effectively promote bone healing has become a keen topic for researchers. The role of macrophages and bone marrow mesenchymal stem cells (BMSCs) in bone healing has gradually come to light with the development of the concept of osteoimmunity. Their interaction regulates the balance between inflammation and regeneration, and when the inflammatory response is over-excited, attenuated, or disturbed, it results in the failure of bone healing. Therefore, an in-depth understanding of the function of macrophages and bone marrow mesenchymal stem cells in bone regeneration and the relationship between the two could provide new directions to promote bone healing. This paper reviews the role of macrophages and bone marrow mesenchymal stem cells in bone healing and the mechanism and significance of their interaction. Several new therapeutic ideas for regulating the inflammatory response in bone healing by targeting macrophages and bone marrow mesenchymal stem cells crosstalk are also discussed.

3D printed strontium-zinc-phosphate bioceramic scaffolds with multiple biological functions for bone tissue regeneration

Calcium phosphate (CaP) bioceramics are broadly employed for bone regeneration due to their excellent biocompatibility and osteoconductivity. However, they are not capable of repairing healing-impaired bone defects such as defects with conditions of ischemia or infection due to restricted bioactivities. In this study, we synthesized single-phased strontium-zinc-phosphate (SZP, SrZn2(PO4)2) bioceramics via a solution combustion method and further fabricated SZP scaffolds using a three-dimensional (3D) printing technique. Compared to 3D printed β-tricalcium phosphate (β-TCP) scaffolds, the 3D printed SZP scaffolds presented comparable porosity, compressive strength, and Young's modulus, but increased ability of osteogenesis, angiogenesis, immunomodulation and anti-bacterial activity. Specifically, 3D printed SZP scaffolds not only led to significantly higher osteogenic differentiation of MC3T3-E1 cells and pro-angiogenesis of human umbilical vein endothelial cells (HUVECs) directly or through macrophage-mediated immunomodulation, but also inhibited the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The in vivo study of the rat cranial bone defect model further confirmed better vascularized bone regeneration in 3D-printed SZP scaffolds. These findings indicate that the proposed 3D-printed SZP scaffolds might be a versatile candidate for bone tissue engineering.

Reduced APPL1 impairs osteogenic differentiation of mesenchymal stem cells by facilitating MGP expression to disrupt the BMP2 pathway in osteoporosis

An imbalance of human mesenchymal stem cells (MSCs) adipogenic and osteogenic differentiation plays an important role in the pathogenesis of osteoporosis. Our previous study verified that APPL1/myoferlin deficiency promotes adipogenic differentiation of mesenchymal stem cells by blocking autophagic flux in osteoporosis. However, the function of APPL1 in the osteogenic differentiation of MSCs remains unclear. This study aimed to investigate the role of APPL1 in the osteogenic differentiation of MSCs in osteoporosis and the underlying regulatory mechanism. In this study, we demonstrated the downregulation of APPL1 expression in osteoporosis patients and osteoporosis mice. The severity of clinical osteoporosis was negatively correlated with the expression of APPL1 in bone marrow MSCs. We found that APPL1 positively regulates the osteogenic differentiation of MSCs in vitro and in vivo. Moreover, RNA sequencing showed that the expression of MGP, an osteocalcin/matrix Gla family member, was significantly upregulated after APPL1 knockdown. Mechanistically, our study showed that reduced APPL1 impaired the osteogenic differentiation of mesenchymal stem cells by facilitating MGP expression to disrupt the BMP2 pathway in osteoporosis. We also evaluated the significance of APPL1 in promoting osteogenesis in a mouse model of osteoporosis. These results suggest that APPL1 may be an important target for the diagnosis and treatment of osteoporosis.

Prospects and Advances in Adoptive Natural Killer Cell Therapy for Unmet Therapeutic Needs in Pediatric Bone Sarcomas

Malignant bone tumors are aggressive tumors, with a high tendency to metastasize, that are observed most frequently in adolescents during rapid growth spurts. Pediatric patients with malignant bone sarcomas, Ewing sarcoma and osteosarcoma, who present with progressive disease have dire survival rates despite aggressive therapy. These therapies can have long-term effects on bone growth, such as decreased bone mineral density and reduced longitudinal growth. New therapeutic approaches are therefore urgently needed for targeting pediatric malignant bone tumors. Harnessing the power of the immune system against cancer has improved the survival rates dramatically in certain cancer types. Natural killer (NK) cells are a heterogeneous group of innate effector cells that possess numerous antitumor effects, such as cytolysis and cytokine production. Pediatric sarcoma cells have been shown to be especially susceptible to NK-cell-mediated killing. NK-cell adoptive therapy confers numerous advantages over T-cell adoptive therapy, including a good safety profile and a lack of major histocompatibility complex restriction. NK-cell immunotherapy has the potential to be a new therapy for pediatric malignant bone tumors. In this manuscript, we review the general characteristics of osteosarcoma and Ewing sarcoma, discuss the long-term effects of sarcoma treatment on bones, and the barriers to effective immunotherapy in bone sarcomas. We then present the laboratory and clinical studies on NK-cell immunotherapy for pediatric malignant bone tumors. We discuss the various donor sources and NK-cell types, the engineering of NK cells and combinatorial treatment approaches that are being studied to overcome the current challenges in adoptive NK-cell therapy, while suggesting approaches for future studies on NK-cell immunotherapy in pediatric bone tumors.

Angiogenesis coupled with osteogenesis in a bone tissue engineering scaffold enhances bone repair in osteoporotic bone defects

Increased life expectancy has resulted in an increase in osteoporosis incidence worldwide. The coupling of angiogenesis and osteogenesis is indispensable for bone repair. Although traditional Chinese medicine (TCM) exerts therapeutic effects on osteoporosis, TCM-related scaffolds, which focus on the coupling of angiogenesis and osteogenesis, have not yet been used for the treatment of osteoporotic bone defects.Panax notoginsengsaponin (PNS), the active ingredient ofPanax notoginseng, was added to a poly (_L-lactic acid) (PLLA) matrix. Osteopractic total flavone (OTF), the active ingredient ofRhizoma Drynariae, was encapsulated in nano-hydroxyapatite/collagen (nHAC) and added to the PLLA matrix. Magnesium (Mg) particles were added to the PLLA matrix to overcome the bioinert character of PLLA and neutralize the acidic byproducts generated by PLLA. In this OTF-PNS/nHAC/Mg/PLLA scaffold, PNS was released faster than OTF. The control group had an empty bone tunnel; scaffolds containing OTF:PNS = 100:0, 50:50, and 0:100 were used as the treatment groups. Scaffold groups promoted new vessel and bone formation, increased the osteoid tissue, and suppressed the osteoclast activity around osteoporotic bone defects. Scaffold groups upregulated the expression levels of angiogenic and osteogenic proteins. Among these scaffolds, the OTF-PNS (50:50) scaffold exhibited a better capacity for osteogenesis than the OTF-PNS (100:0 and 0:100) scaffolds. Activation of the bone morphogenic protein (BMP)-2/BMP receptor (BMPR)-1A/runt-related transcription factor (RUNX)-2signaling pathway may be a possible mechanism for the promotion of osteogenesis. Our study demonstrated that the OTF-PNS/nHAC/Mg/PLLA scaffold could promote osteogenesis via the coupling of angiogenesis and osteogenesis in osteoporotic rats with bone defects, and activating theBMP-2/BMPR1A/RUNX2signaling pathway may be an osteogenesis-related mechanism. However, further experiments are necessary to facilitate its practical application in the treatment of osteoporotic bone defects.

Multicellular Bioprinting of Biomimetic Inks for Tendon-to-Bone Regeneration

Tendon-to-bone interface has a hierarchical structure and gradient component that are conducive to distributing the stresses to achieve movement. Conventional biomaterials lack the capacity to induce synchronous repair of multiple tissues, resulting in the failure of the interface repair. Biomimetic strategies have attracted enormous attention in the field of complex structure regeneration because they can meet the different physiological requirements of multiple tissues. Herein, a biomimetic ink mimicking tendon/bone tissues is developed by combining tendon/bone-related cells and Mo-containing silicate (MS) bioceramics. Subsequently, biomimetic multicellular scaffolds are fabricated to achieve the simulation of the hierarchical structure and cellular composition of tendon-to-bone interfaces by the spatial distribution of the biomimetic inks via 3D bioprinting, which is of great significance for inducing the regeneration of complex structures in the interface region. In addition, attributed to the desirable ionic microenvironment created by MS bioceramics, the biomimetic scaffolds possess the dual function of inducing tendon/bone-related cells tenogenic and osteogenic differentiation in vitro, and promote the integrated regeneration of tendon-to-bone interfaces in vivo. The study offers a feasible strategy to construct biomimetic multicellular scaffolds with bifunction for inducing multi-lineage tissue regeneration, especially for regenerating soft-to-hard tissue interfaces.

Plum-Derived Exosome-like Nanovesicles Induce Differentiation of Osteoblasts and Reduction of Osteoclast Activation

Osteoblasts and osteoclasts play crucial roles in bone formation and bone resorption. We found that plum-derived exosome-like nanovesicles (PENVs) suppressed osteoclast activation and modulated osteoblast differentiation. PENVs increased the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells and osteoblasts from mouse bone marrow cultures. Notably, PENVs elevated the expression of osteoblastic transcription factors and osteoblast differentiation marker proteins in MC3T3-E1 cells. Higher levels of phosphorylated BMP-2, p38, JNK, and smad1 proteins were detected in PENV-treated MC3T3-E1 cells. Additionally, the number of TRAP-positive cells was significantly decreased in PENV-treated osteoclasts isolated from osteoblasts from mouse bone marrow cultures. Importantly, osteoclastogenesis of marker proteins such as PPAR-gamma, NFATc1, and c-Fos were suppressed by treatment with PENVs (50 μg/mL). Taken together, these results demonstrate that PENVs can be used as therapeutic targets for treating bone-related diseases by improving osteoblast differentiation and inhibiting osteoclast activation for the first time.

Whole-genome resequencing to unveil genetic characteristics and selection signatures of specific pathogen-free ducks

Specific pathogen-free ducks are important high-grade laboratory animals, with a key role in research related to poultry biosecurity, production, and breeding. However, the genetic characteristics of experimental duck varieties remain poorly explored. Herein we performed whole-genome resequencing to construct a single nucleotide polymorphism genetic map of the genomes of 3 experimental duck varieties [Jinding ducks (JD), Shaoxing ducks (SX), and Fujian Shanma ducks (SM)] to determine their genetic characteristics and identify selection signatures. Subsequent analyses of population structure and genetic diversity revealed that each duck variety formed a monophyletic group, with SM showing richer genetic diversity than JD and SX. Further, on exploring shared selection signatures, we found 2 overlapping genomic regions on chromosome Z of all experimental ducks, which comprised immune response-related genes (IL7R and IL6ST). Moreover, growth and skeletal development (IGF1R and GDF5), meat quality (FoxO1), and stress resistance (HSP90B1 and Gpx8-b) candidate gene loci were identified in strongly selected signatures specific to JD, SM, and SX, respectively. Our results identified the population genetic basis of experimental ducks at the whole-genome level, providing a framework for future molecular investigations of genetic variations and phenotypic changes. We believe that such studies will eventually contribute to the management of experimental animal resources.

Histone methyltransferase SETDB1 promotes osteogenic differentiation in osteoporosis by activating OTX2-mediated BMP-Smad and Wnt/β-catenin pathways

Osteogenic differentiation plays important roles in the pathogenesis of osteoporosis. In this study, we explored the regulatory mechanism of histone methyltransferase SET domain bifurcated 1 (SETDB1) underlying the osteogenic differentiation in osteoporosis. The common osteoporosis-related genes were retrieved from the GeneCards, CTD, and Phenolyzer databases. The enrichment analysis was conducted on the candidate osteoporosis-related genes using the PANTHER software, and the binding site between transcription factors and target genes predicted by hTFtarget. The bioinformatics analyses suggested 6 osteoporosis-related chromatin/chromatin binding protein or regulatory proteins (HDAC4, SIRT1, SETDB1, MECP2, CHD7, and DKC1). Normal and osteoporosis tissues were collected from osteoporosis patients to examine the expression of SETDB1. It was found that SETDB1 was poorly expressed in osteoporotic femoral tissues, indicating that SETDB1 might be involved in the development of osteoporosis. We induced SETDB1 overexpression/knockdown, orthodenticle homeobox 2 (OTX2) overexpression, activation of Wnt/β-catenin or BMP-Smad pathways alone or in combination in osteoblasts or ovariectomized mice. The data indicated that SETDB1 methylation regulated H3K9me3 in the OTX2 promoter region and inhibited the expression of OTX2. Besides, the BMP-Smad and Wnt/β-catenin pathways were inhibited by OTX2, thereby resulting in inhibited osteogenic differentiation. Animal experiments showed that overexpressed SETDB1 could promote the increase of calcium level and differentiation of femoral tissues. In conclusion, upregulation of SETDB1 promotes osteogenic differentiation by inhibiting OTX2 and activating the BMP-Smad and Wnt/β-catenin pathways in osteoporosis.

Application of Biomaterials in Treating Early Osteonecrosis of the Femoral Head: Research Progress and Future Perspectives

Osteonecrosis of the femoral head (ONFH), a progressive pathological process of femoral head ischemia and osteocyte necrosis, is a refractory orthopedic disease caused by multiple etiologies and there is no complete cure at present. With the extension of ONFH duration, osteocyte apoptosis and trabecular bone loss can decrease the load-bearing capacity of the femoral head, which leads to the collapse of the articular cartilage and subchondral bone. Therefore, an urgent clinical need exists to develop effective treatment strategies of early-stage ONFH for maintaining the hip joint function and preventing femoral head collapse. In recent years, extensive attention has been paid to the application of diverse biomaterials in treating early ONFH for sustaining the normal morphology and function of the autologous femoral head, and slowing disease progression. Herein, we review the research progress of bone grafts, metallic materials, bioceramics, bioglasses and polymer materials for early ONFH treatment, and discuss the biological mechanisms of bone repair and regeneration in the femoral-head necrotic area. We propose suggestions for future research directions, from a special perspective of improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts (VAOs) generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts (BAOs) and BAO-mediated bone resorption. This review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH. STATEMENT OF SIGNIFICANCE: We believe that at least three aspects of this manuscript make it interesting to readers of the Acta Biomaterialia. First, we briefly summarize the incidence, pathogenesis, risk factors, classification criteria and treatment of early osteonecrosis of the femoral head (ONFH). Second, we review the research progress in biomaterials for early ONFH treatment and the biological mechanisms of bone repair and regeneration in femoral-head necrotic area. Third, we propose future research progress on improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts and bone resorption. We hope this review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH.

Persicae Semen Promotes Bone Union in Rat Fractures by Stimulating Osteoblastogenesis through BMP-2 and Wnt Signaling

Fractures cause extreme pain to patients and impair movement, thereby significantly reducing their quality of life. However, in fracture patients, movement of the fracture site is restricted through application of a cast, and they are reliant on conservative treatment through calcium intake. Persicae semen (PS) is the dried mature seeds of Prunus persica (L.) Batsch, and in this study the effects of PS on osteoblast differentiation and bone union promotion were investigated. The osteoblast-differentiation-promoting effect of PS was investigated through alizarin red S and Von Kossa staining, and the regulatory role of PS on BMP-2 (Bmp2) and Wnt (Wnt10b) signaling, representing a key mechanism, was demonstrated at the protein and mRNA levels. In addition, the bone-union-promoting effect of PS was investigated in rats with fractured femurs. The results of the cell experiments showed that PS promotes mineralization and upregulates RUNX2 through BMP-2 and Wnt signaling. PS induced the expression of various osteoblast genes, including Alpl, Bglap, and Ibsp. The results of animal experiments show that the PS group had improved bone union and upregulated expression of osteogenic genes. Overall, the results of this study suggest that PS can promote fracture recovery by upregulating osteoblast differentiation and bone formation, and thus can be considered a new therapeutic alternative for fracture patients.

Can a low dosage of recombinant human bone morphogenetic protein-2 loaded on collagen sponge induce ectopic bone?

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is one of the growth factors that may induce the formation of new bone. The aim was to determine the efficacy of low doses of rhBMP-2 for bone regeneration using a collagen sponge as a carrier. Three doses of rhBMP-2 (1.167, 0.117, and 0.039 mg/mL) were combined with an absorbable collagen sponge (ACS) as a delivery vehicle. The rhBMP-2/ACS implants were placed in the subcutaneous tissues of rat backs. X-ray microcomputed tomography (micro-CT) and histological analysis were used to evaluate bone formation. The samples treated with 1.167 mg/mL of rhBMP-2 showed greater bone formation than the samples treated with 0.117 mg/mL of rhBMP-2 four weeks after surgery. However, there was no evidence of bone formation in the samples that were treated with 0.039 mg/mL of rhBMP-2. It was found that rhBMP-2 was osteogenic even at one-tenth of its manufacturer's recommended concentration (1.167 mg/mL), indicating its potential for clinical use at lower concentrations.

Preparation, modification, and clinical application of porous tantalum scaffolds

Porous tantalum (Ta) implants have been developed and clinically applied as high-quality implant biomaterials in the orthopedics field because of their excellent corrosion resistance, biocompatibility, osteointegration, and bone conductivity. Porous Ta allows fine bone ingrowth and new bone formation through the inner space because of its high porosity and interconnected pore structure. It contributes to rapid bone integration and long-term stability of osseointegrated implants. Porous Ta has excellent wetting properties and high surface energy, which facilitate the adhesion, proliferation, and mineralization of osteoblasts. Moreover, porous Ta is superior to classical metallic materials in avoiding the stress shielding effect, minimizing the loss of marginal bone, and improving primary stability because of its low elastic modulus and high friction coefficient. Accordingly, the excellent biological and mechanical properties of porous Ta are primarily responsible for its rising clinical translation trend. Over the past 2 decades, advanced fabrication strategies such as emerging manufacturing technologies, surface modification techniques, and patient-oriented designs have remarkably influenced the microstructural characteristic, bioactive performance, and clinical indications of porous Ta scaffolds. The present review offers an overview of the fabrication methods, modification techniques, and orthopedic applications of porous Ta implants.

Bone marrow mesenchymal stem cells paracrine TGF-β1 to mediate the biological activity of osteoblasts in bone repair

BACKGROUND

Bone marrow mesenchymal stem cells (BMSCs) are an important source of seed cells for regenerative medicine and tissue engineering therapy. BMSCs have multiple differentiation potentials and can release paracrine factors to facilitate tissue repair. Although the role of the osteogenic differentiation of BMSCs has been fully confirmed, the function and mechanism of BMSC paracrine factors in bone repair are still largely unclear. This study aimed to determine the roles of transforming growth factor beta-1 (TGF-β1) produced by BMSCs in bone tissue repair.

METHODS

To confirm our hypothesis, we used a Transwell system to coculture hBMSCs and human osteoblast-like cells without contact, which could not only avoid the interference of the osteogenic differentiation of hBMSCs but also establish the cell-cell relationship between hBMSCs and human osteoblast-like cells and provide stable paracrine substances. In the transwell coculture system, alkaline phosphatase activity, mineralized nodule formation, cell migration and chemotaxis analysis assays were conducted.

RESULTS

Osteogenesis, migration and chemotaxis of osteoblast-like cells were regulated by BMSCs in a paracrine manner via the upregulation of osteogenic and migration-associated genes. A TGF-β receptor I inhibitor (LY3200882) significantly antagonized BMSC-induced biological activity and related gene expression in osteoblast-like cells. Interestingly, coculture with osteoblast-like cells significantly increased the production of TGF-β1 by BMSCs, and there was potential intercellular communication between BMSCs and osteoblast-like cells.

CONCLUSIONS

Our findings provide evidence that the biological mechanism of BMSC-produced TGF-β1 promotes bone regeneration and repair, providing a theoretical basis and new directions for the application of BMSC transplantation in the treatment of osteonecrosis and bone injury.

Tax1 binding protein 3 regulates osteogenic and adipogenic differentiation through inactivating Wnt/β-catenin signalling

Tax1 binding protein 3 (Tax1bp3) is a PDZ domain-containing protein that is overexpressed in cancer. Previous studies recognized Tax1bp3 as an inhibitor of β-catenin. Till now it is not known whether Tax1bp3 regulates osteogenic and adipogenic differentiation of mesenchymal progenitor cells. In the current study, the data showed that Tax1bp3 was expressed in bone and was increased in the progenitor cells when induced toward osteoblast and adipocyte differentiation. The overexpression of Tax1bp3 in the progenitor cells inhibited osteogenic differentiation and conversely stimulated adipogenic differentiation, and the knockdown of Tax1bp3 affected the differentiation of the progenitor cells oppositely. Ex vivo experiments using the primary calvarial osteoblasts from osteoblast-specific Tax1bp3 knock-in mice also demonstrated the anti-osteogenic and pro-adipogenic function of Tax1bp3. Mechanistic investigations revealed that Tax1bp3 inhibited the activation of canonical Wnt/β-catenin and bone morphogenetic proteins (BMPs)/Smads signalling pathways. Taken together, the current study has provided evidences demonstrating that Tax1bp3 inactivates Wnt/β-catenin and BMPs/Smads signalling pathways and reciprocally regulates osteogenic and adipogenic differentiation from mesenchymal progenitor cells. The inactivation of Wnt/β-catenin signalling may be involved in the reciprocal role of Tax1bp3.

Post-Transcriptional Regulatory Crosstalk between MicroRNAs and Canonical TGF-β/BMP Signalling Cascades on Osteoblast Lineage: A Comprehensive Review

MicroRNAs (miRNAs) are a family of small, single-stranded, and non-protein coding RNAs about 19 to 22 nucleotides in length, that have been reported to have important roles in the control of bone development. MiRNAs have a strong influence on osteoblast differentiation through stages of lineage commitment and maturation, as well as via controlling the activities of osteogenic signal transduction pathways. Generally, miRNAs may modulate cell stemness, proliferation, differentiation, and apoptosis by binding the 3'-untranslated regions (3'-UTRs) of the target genes, which then can subsequently undergo messenger RNA (mRNA) degradation or protein translational repression. MiRNAs manage the gene expression in osteogenic differentiation by regulating multiple signalling cascades and essential transcription factors, including the transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP), Wingless/Int-1(Wnt)/β-catenin, Notch, and Hedgehog signalling pathways; the Runt-related transcription factor 2 (RUNX2); and osterix (Osx). This shows that miRNAs are essential in regulating diverse osteoblast cell functions. TGF-βs and BMPs transduce signals and exert diverse functions in osteoblastogenesis, skeletal development and bone formation, bone homeostasis, and diseases. Herein, we highlighted the current state of in vitro and in vivo research describing miRNA regulation on the canonical TGF-β/BMP signalling, their effects on osteoblast linage, and understand their mechanism of action for the development of possible therapeutics. In this review, particular attention and comprehensive database searches are focused on related works published between the years 2000 to 2022, using the resources from PubMed, Google Scholar, Scopus, and Web of Science.

Antineoplastic Nature of WWOX in Glioblastoma Is Mainly a Consequence of Reduced Cell Viability and Invasion

Following the discovery of WWOX, research has moved in many directions, including the role of this putative tumor suppressor in the central nervous system and related diseases. The task of determining the nature of WWOX in glioblastoma (GBM) is still considered to be at the initial stage; however, the influence of this gene on the GBM malignant phenotype has already been reported. Because most of the available in vitro research does not consider several cellular GBM models or a wide range of investigated biological assays, the present study aimed to determine the main processes by which WWOX exhibits anticancer properties in GBM, while taking into account the phenotypic heterogeneity between cell lines. Ectopic WWOX overexpression was studied in T98G, DBTRG-05MG, U251MG, and U87MG cell lines that were compared with the use of assays investigating cell viability, proliferation, apoptosis, adhesion, clonogenicity, three-dimensional and anchorage-independent growth, and invasiveness. Observations presenting the antineoplastic properties of WWOX were consistent for T98G, U251MG, and U87MG. Increased proliferation and tumor growth were noted in WWOX-overexpressing DBTRG-05MG cells. A possible explanation for this, arrived at via bioinformatics tools, was linked to the TARDBP transcription factor and expression differences of USP25 and CPNE2 that regulate EGFR surface abundance. Collectively, and despite various cell line-specific circumstances, WWOX exhibits its anticancer nature mainly via a reduction of cell viability and invasiveness of glioblastoma.

Progress of Wnt Signaling Pathway in Osteoporosis

Osteoporosis, one of the serious health diseases, involves bone mass loss, bone density diminishing, and degeneration of bone microstructure, which is accompanied by a tendency toward bone fragility and a predisposition to fracture. More than 200 million people worldwide suffer from osteoporosis, and the cost of treating osteoporotic fractures is expected to reach at least $25 billion by 2025. The generation and development of osteoporosis are regulated by genetic factors and regulatory factors such as TGF-β, BMP, and FGF through multiple pathways, including the Wnt signaling pathway, the Notch signaling pathway, and the MAPK signaling pathway. Among them, the Wnt signaling pathway is one of the most important pathways. It is not only involved in bone development and metabolism but also in the differentiation and proliferation of chondrocytes, mesenchymal stem cells, osteoclasts, and osteoblasts. Dkk-1 and SOST are Wnt inhibitory proteins that can inhibit the activation of the canonical Wnt signaling pathway and block the proliferation and differentiation of osteoblasts. Therefore, they may serve as potential targets for the treatment of osteoporosis. In this review, we analyzed the mechanisms of Wnt proteins, β-catenin, and signaling molecules in the process of signal transduction and summarized the relationship between the Wnt signaling pathway and bone-related cells. We hope to attract attention to the role of the Wnt signaling pathway in osteoporosis and offer new perspectives and approaches to making a diagnosis and giving treatment for osteoporosis.

Whole-genome sequencing reveals a complex African population demographic history and signatures of local adaptation

We conduct high coverage (>30×) whole-genome sequencing of 180 individuals from 12 indigenous African populations. We identify millions of unreported variants, many predicted to be functionally important. We observe that the ancestors of southern African San and central African rainforest hunter-gatherers (RHG) diverged from other populations >200 kya and maintained a large effective population size. We observe evidence for ancient population structure in Africa and for multiple introgression events from "ghost" populations with highly diverged genetic lineages. Although currently geographically isolated, we observe evidence for gene flow between eastern and southern Khoesan-speaking hunter-gatherer populations lasting until ∼12 kya. We identify signatures of local adaptation for traits related to skin color, immune response, height, and metabolic processes. We identify a positively selected variant in the lightly pigmented San that influences pigmentation in vitro by regulating the enhancer activity and gene expression of PDPK1.

Periostin splice variants affect craniofacial growth by influencing chondrocyte hypertrophy

INTRODUCTION

Periostin, an extracellular matrix protein, plays an important role in osteogenesis and is also known to activate several signals that contribute to chondrogenesis. The absence of periostin in periostin knockout mice leads to several disorders such as craniosynostosis and periostitis. There are several splice variants with different roles in heart disease and myocardial infarction. However, little is known about each variant's role in chondrogenesis, followed by bone formation. Therefore, the aim of this study is to investigate the role of several variants in chondrogenesis differentiation and bone formation in the craniofacial region. Periostin splice variants included a full-length variant (Control), a variant lacking exon 17 (ΔEx17), a variant lacking exon 21 (ΔEx21), and another variant lacking both exon 17 and 21 ***(ΔEx17&21).

MATERIALS AND METHODS

We used C56BL6/N mice (n = 6) for the wild type (Control)*** and the three variant type mice (n = 6 each) to identify the effect of each variant morphologically and histologically. Micro-computed tomography demonstrated a smaller craniofacial skeleton in ΔEx17s, ΔEx21s, and ΔEx17&21s compared to Controls, especially the mandibular bone. We, thus, focused on the mandibular condyle.

RESULTS

The most distinctive histological observation was that each defected mouse appeared to have more hypertrophic chondrocytes than Controls. Real-time PCR demonstrated the differences among the group. Moreover, the lack of exon 17 or exon 21 in periostin leads to inadequate chondrocyte differentiation and presents in a diminutive craniofacial skeleton.

DISCUSSION

Therefore, these findings suggested that each variant has a significant role in chondrocyte hypertrophy, leading to suppression of bone formation.

Molecular Basis beyond Interrelated Bone Resorption/Regeneration in Periodontal Diseases: A Concise Review

Periodontitis is the sixth most common chronic inflammatory disease, destroying the tissues supporting the teeth. There are three distinct stages in periodontitis: infection, inflammation, and tissue destruction, where each stage has its own characteristics and hence its line of treatment. Illuminating the underlying mechanisms of alveolar bone loss is vital in the treatment of periodontitis to allow for subsequent reconstruction of the periodontium. Bone cells, including osteoclasts, osteoblasts, and bone marrow stromal cells, classically were thought to control bone destruction in periodontitis. Lately, osteocytes were found to assist in inflammation-related bone remodeling besides being able to initiate physiological bone remodeling. Furthermore, mesenchymal stem cells (MSCs) either transplanted or homed exhibit highly immunosuppressive properties, such as preventing monocytes/hematopoietic precursor differentiation and downregulating excessive release of inflammatory cytokines. In the early stages of bone regeneration, an acute inflammatory response is critical for the recruitment of MSCs, controlling their migration, and their differentiation. Later during bone remodeling, the interaction and balance between proinflammatory and anti-inflammatory cytokines could regulate MSC properties, resulting in either bone formation or bone resorption. This narrative review elaborates on the important interactions between inflammatory stimuli during periodontal diseases, bone cells, MSCs, and subsequent bone regeneration or bone resorption. Understanding these concepts will open up new possibilities for promoting bone regeneration and hindering bone loss caused by periodontal diseases.

Polydopamine-coated 3D-printed β-tricalcium phosphate scaffolds to promote the adhesion and osteogenesis of BMSCs for bone-defect repair: mRNA transcriptomic sequencing analysis

Cellular bioactivity and tissue regeneration can be affected by coatings on tissue-engineered scaffolds. Using mussel-inspired polydopamine (PDA) is a convenient and effective approach to surface modification. Therefore, 3D-printed β-tricalcium phosphate (β-TCP) scaffolds were coated with PDA in this study. The effects of the scaffolds on the adhesion and osteogenic differentiation of seeded bone marrow mesenchymal stem cells (BMSCs) in vitro and on new-bone formation in vivo were investigated. The potential mechanisms and related differential genes were assessed using mRNA sequencing. It was seen that PDA coating increased the surface roughness of the 3D-printed β-TCP scaffolds. Furthermore, it prompted the adhesion and osteogenic differentiation of seeded BMSCs. mRNA sequencing analysis revealed that PDA coating might affect the osteogenic differentiation of BMSCs through the calcium signaling pathway, Wnt signaling pathway, TGF-beta signaling pathway, etc. Moreover, the expression of osteogenesis-related genes, such as R-spondin 1 and chemokine c-c-motif ligand 2, was increased. Finally, both the 3D-printed β-TCP scaffolds and PDA-coated scaffolds could significantly accelerate the formation of new bone in critical-size calvarial defects in rats compared with the control group; and the new bone formation was obviously higher in the PDA-coated scaffolds than in β-TCP scaffolds. In summary, 3D-printed β-TCP scaffolds with a PDA coating can improve the physicochemical characteristics and cellular bioactivity of the scaffold surface for bone regeneration. Potential differential genes were identified, which can be used as a foundation for further research.

A novel biologically hierarchical hydrogel with osteoblast precursor-targeting extracellular vesicles ameliorates bone loss in vivo via the sequential action of antagomiR-200b-3p and antagomiR-130b-3p

Osteoporotic fracture is a major health problem plaguing the ageing society, and improving its treatment is an urgent challenge. How to ameliorate bone loss determines the recovery of such fractures. Extracellular vesicle (EV)-loaded hydrogel has the capacity to treat osteoporotic fractures due to its pro-osteogenic property. And balancing proliferation and maturation of osteoblast precursors (OBPs) is of great significance to avoid OBP depletion, which is lacking in current treatment. Based on osteoblastogenic miRNAs, this study aimed to explore the efficacies of the combination of hierarchical hydrogel and EVs altering functional miRNAs level in bone loss. Through bioinformatics analyses, we screened out proliferative gene-targeting miR-200b-3p and osteogenic gene-targeting miR-130b-3p. And antagomiR-200b-3p (ant-200b) enhanced OBP proliferation, and antagomiR-130b-3p (ant-130b) promoted OBP differentiation. After confirming the directional effect of Fibronectin (Fn1) on OBPs, we prepared OBP-targeting EVs. Furthermore, encapsulation of two antagomiRNAs in EVs enhanced the respective effect of ant-200b and ant-130b. Notably, hierarchically injectable hydrogel exerted an effective function in promoting the sequential delivery of EVs-200b and EVs-130b. Importantly, hierarchical hydrogel containing dual EVs effectively ameliorated bone loss. Overall, hierarchical hydrogel based on two antagomiRNAs effectively improves bone loss in vivo due to its role in promoting OBP proliferation and maturation sequentially.