Matrix Metalloproteinases in Bone Resorption, Remodeling, and Repair

Suppression of bone resorption by Mori Radicis Cortex through NFATc1 and c-Fos signaling-mediated inhibition of osteoclast differentiation

BACKGROUND

Mori Radicis Cortex (MRC) is the root bark of the mulberry family as Morus alba L. In Korea, it is known as "Sangbaegpi". Although MRC has demonstrated anti-inflammatory and antioxidant effects, its specific mechanisms of action and impact on osteoporosis remain poorly understood.

METHODS

To investigate the antiosteoporosis effect of MRC, we examined the level of osteoclast differentiation inhibition in receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced-RAW 264.7 cells and animal models of ovariectomy (OVX) with MRC. Serum analysis in OVX animals was investigated by enzyme-linked immunosorbent assay (ELISA), and bone density analysis was confirmed by micro-computed tomography (micro-CT). The expression analysis of nuclear factor of activated T cells 1 (NFATc1) was confirmed by immunohistochemistry (IHC) in femur tissue. In addition, osteoclast differentiation inhibition was measured using tartrate-resistant acid phosphatase (TRAP). mRNA analysis was performed using reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression analysis was investigated by western blot.

RESULTS

Micro-CT analysis showed that MRC effectively inhibited bone loss in the OVX-induced rat model. MRC also inhibited the expression of alkaline phosphatase (ALP) and TRAP in serum. Histological analysis showed that MRC treatment increased bone density and IHC analysis showed that MRC significantly inhibited the expression of NFATc1. In RANKL-induced-RAW 264.7 cells, MRC significantly reduced TRAP activity and actin ring formation. In addition, MRC significantly inhibited the expression of NFATc1 and c-Fos, and suppressed the mRNA expression.

CONCLUSION

Based on micro-CT, serum and histological analysis, MRC effectively inhibited bone loss in an OVX-induced rat model. In addition, MRC treatment suppressed the expression of osteoclast differentiation, fusion, and bone resorption markers through inhibition of NFATc1/c-Fos expression in RANKL-induced RAW 264.7 cells, ultimately resulting in a decrease in osteoclast activity. These results demonstrate that MRC is effective in preventing bone loss through inhibiting osteoclast differentiation and activity.

Pleurotus sajor-caju (Fr.) Singer β-1,3-Glucanoligosaccharide (Ps-GOS) Suppresses RANKL-Induced Osteoclast Differentiation and Function in Pre-Osteoclastic RAW 264.7 Cells by Inhibiting the RANK/NFκB/cFOS/NFATc1 Signalling Pathway

Edible grey oyster mushroom, Pleurotus sajor-caju, β (1,3), (1,6) glucan possesses a wide range of biological activities, including anti-inflammation, anti-microorganism and antioxidant. However, its biological activity is limited by low water solubility resulting from its high molecular weight. Our previous study demonstrated that enzymatic hydrolysis of grey oyster mushroom β-glucan using Hevea β-1,3-glucanase isozymes obtains a lower molecular weight and higher water solubility, Pleurotus sajor-caju glucanoligosaccharide (Ps-GOS). Additionally, Ps-GOS potentially reduces osteoporosis by enhancing osteoblast-bone formation, whereas its effect on osteoclast-bone resorption remains unknown. Therefore, our study investigated the modulatory activities and underlying mechanism of Ps-GOS on Receptor activator of nuclear factor kappa-Β ligand (RANKL) -induced osteoclastogenesis in pre-osteoclastic RAW 264.7 cells. Cell cytotoxicity of Ps-GOS on RAW 264.7 cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and its effect on osteoclast differentiation was determined by tartrate-resistant acid phosphatase (TRAP) staining. Additionally, its effect on osteoclast bone-resorptive ability was detected by pit formation assay. The osteoclastogenic-related factors were assessed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), Western blot and immunofluorescence. The results revealed that Ps-GOS was non-toxic and significantly suppressed the formation of mature osteoclast multinucleated cells and their resorption activity by reducing the number of TRAP-positive cells and pit formation areas in a dose-dependent manner. Additionally, Ps-GOS attenuated the nuclear factor kappa light chain-enhancer of activated B cells' P65 (NFκB-P65) expression and their subsequent master osteoclast modulators, including nuclear factor of activated T cell c1 (NFATc1) and Fos proto-oncogene (cFOS) via the NF-κB pathway. Furthermore, Ps-GOS markedly inhibited RANK expression, which serves as an initial transmitter of many osteoclastogenesis-related cascades and inhibited proteolytic enzymes, including TRAP, matrix metallopeptidase 9 (MMP-9) and cathepsin K (CTK). These findings indicate that Ps-GOS could potentially be beneficial as an effective natural agent for bone metabolic disease.

Osteosarcoma cell death induced by innovative scaffolds doped with chemotherapeutics

Osteosarcoma (OS) cancer treatments include systemic chemotherapy and surgical resection. In the last years, novel treatment approaches have been proposed, which employ a drug-delivery system to prevent offside effects and improves treatment efficacy. Locally delivering anticancer compounds improves on high local concentrations with more efficient tumour-killing effect, reduced drugs resistance and confined systemic effects. Here, the synthesis of injectable strontium-doped calcium phosphate (SrCPC) scaffold was proposed as drug delivery system to combine bone tissue regeneration and anticancer treatment by controlled release of methotrexate (MTX) and doxorubicin (DOX), coded as SrCPC-MTX and SrCPC-DOX, respectively. The drug-loaded cements were tested in an in vitro model of human OS cell line SAOS-2, engineered OS cell line (SAOS-2-eGFP) and U2-OS. The ability of doped scaffolds to induce OS cell death and apoptosis was assessed analysing cell proliferation and Caspase-3/7 activities, respectively. To determine if OS cells grown on doped-scaffolds change their migratory ability and invasiveness, a wound-healing assay was performed. In addition, the osteogenic potential of SrCPC material was evaluated using human adipose derived-mesenchymal stem cells. Osteogenic markers such as (i) the mineral matrix deposition was analysed by alizarin red staining; (ii) the osteocalcin (OCN) protein expression was investigated by enzyme-linked immunosorbent assay test, and (iii) the osteogenic process was studied by real-time polymerase chain reaction array. The delivery system induced cell-killing cytotoxic effects and apoptosis in OS cell lines up to Day 7. SrCPC demonstrates a good cytocompatibility and it induced upregulation of osteogenic genes involved in the skeletal development pathway, together with OCN protein expression and mineral matrix deposition. The proposed approach, based on the local, sustained release of anticancer drugs from nanostructured biomimetic drug-loaded cements is promising for future therapies aiming to combine bone regeneration and anticancer local therapy.

Smart Hydrogels for Tissue Regeneration

The rapid growth in the portion of the aging population has led to a consequent increase in demand for biomedical hydrogels, together with an assortment of challenges that need to be overcome in this field. Smart hydrogels can autonomously sense and respond to the physiological/pathological changes of the tissue microenvironment and continuously adapt the response according to the dynamic spatiotemporal shifts in conditions. This along with other favorable properties, make smart hydrogels excellent materials for employing toward improving the precision of treatment for age-related diseases. The key factor during the smart hydrogel design is on accurately identifying the characteristics of natural tissues and faithfully replicating the composition, structure, and biological functions of these tissues at the molecular level. Such hydrogels can accurately sense distinct physiological and external factors such as temperature and biologically active molecules, so they may in turn actively and promptly adjust their response, by regulating their own biological effects, thereby promoting damaged tissue repair. This review summarizes the design strategies employed in the creation of smart hydrogels, their response mechanisms, as well as their applications in field of tissue engineering; and concludes by briefly discussing the relevant challenges and future prospects.

Matrix Metalloproteinases in the Periodontium-Vital in Tissue Turnover and Unfortunate in Periodontitis

The extracellular matrix (ECM) is a complex non-cellular three-dimensional macromolecular network present within all tissues and organs, forming the foundation on which cells sit, and composed of proteins (such as collagen), glycosaminoglycans, proteoglycans, minerals, and water. The ECM provides a fundamental framework for the cellular constituents of tissue and biochemical support to surrounding cells. The ECM is a highly dynamic structure that is constantly being remodeled. Matrix metalloproteinases (MMPs) are among the most important proteolytic enzymes of the ECM and are capable of degrading all ECM molecules. MMPs play a relevant role in physiological as well as pathological processes; MMPs participate in embryogenesis, morphogenesis, wound healing, and tissue remodeling, and therefore, their impaired activity may result in several problems. MMP activity is also associated with chronic inflammation, tissue breakdown, fibrosis, and cancer invasion and metastasis. The periodontium is a unique anatomical site, composed of a variety of connective tissues, created by the ECM. During periodontitis, a chronic inflammation affecting the periodontium, increased presence and activity of MMPs is observed, resulting in irreversible losses of periodontal tissues. MMP expression and activity may be controlled in various ways, one of which is the inhibition of their activity by an endogenous group of tissue inhibitors of metalloproteinases (TIMPs), as well as reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

Emerging Role of Non-collagenous Bone Proteins as Osteokines in Extraosseous Tissues

Bone is a unique tissue, composed of various types of cells embedded in a calcified extracellular matrix (ECM), whose dynamic structure consists of organic and inorganic compounds produced by bone cells. The main inorganic component is represented by hydroxyapatite, whilst the organic ECM is primarily made up of type I collagen and non-collagenous proteins. These proteins play an important role in bone homeostasis, calcium regulation, and maintenance of the hematopoietic niche. Recent advances in bone biology have highlighted the importance of specific bone proteins, named "osteokines", possessing endocrine functions and exerting effects on nonosseous tissues. Accordingly, osteokines have been found to act as growth factors, cell receptors, and adhesion molecules, thus modifying the view of bone from a static tissue fulfilling mobility to an endocrine organ itself. Since bone is involved in a paracrine and endocrine cross-talk with other tissues, a better understanding of bone secretome and the systemic roles of osteokines is expected to provide benefits in multiple topics: such as identification of novel biomarkers and the development of new therapeutic strategies. The present review discusses in detail the known osseous and extraosseous effects of these proteins and the possible respective clinical and therapeutic significance.

Importance of Metalloproteinase Enzyme Group in Selected Skeletal System Diseases

Bone tissue is a dynamic structure that is involved in maintaining the homeostasis of the body due to its multidirectional functions, such as its protective, endocrine, or immunological role. Specialized cells and the extracellular matrix (ECM) are responsible for the remodeling of specific bone structures, which alters the biomechanical properties of the tissue. Imbalances in bone-forming elements lead to the formation and progression of bone diseases. The most important family of enzymes responsible for bone ECM remodeling are matrix metalloproteinases (MMPs)-enzymes physiologically present in the body's tissues and cells. The activity of MMPs is maintained in a state of balance; disruption of their activity is associated with the progression of many groups of diseases, including those of the skeletal system. This review summarizes the current understanding of the role of MMPs in bone physiology and the pathophysiology of bone tissue and describes their role in specific skeletal disorders. Additionally, this work collects data on the potential of MMPs as bio-markers for specific skeletal diseases.

Echinococcus granulosus promotes bone resorption by increasing osteoclasts differentiation

Osseous cystic echinococcosis (CE) is a rare disease caused by Echinococcus granulosus, which is characterized by high morbidity, disability, and mortality. However, it is severely neglected due to its mainly regional epidemic. The development of osseous CE is usually accompanied by severe bone erosion and destruction at the site of infection; however, there is a gap in research on the mechanism of this phenomenon. The current treatment for this disease is single-sided, ineffective, and has a high rate of disability and recurrence. Our study investigated the mechanism of bone destruction caused by osseous CE and provided a theoretical basis for basic research and innovative ideas for treating clinical disease. A co-culture system of osteoclast progenitor cells and protoscoleces (PSCs) was established to test the effects of PSCs on osteoclast differentiation. We also created two disease models of spinal and femoral CE, with the highest incidence of osseous CE. We verified the effect of E. granulosus on osteoclasts at the infection site in vivo. The stimulatory effect of E. granulosus on osteoclast formation was confirmed by in vivo and in vitro experiments. This study elucidates the elementary mechanism of bone destruction in osseous CE and fills a gap in the field of basic osseous CE research, which is conducive to treating the disease.

Mmp2 Deficiency Leads to Defective Parturition and High Dystocia Rates in Mice

Parturition is the final and essential step for mammalian reproduction. While the uterus is quiescent during pregnancy, fundamental changes arise in the myometrial contractility, inducing fetal expulsion. Extracellular matrix (ECM) remodeling is fundamental for these events. The gelatinases subgroup of matrix metalloproteinases (MMPs), MMP2 and MMP9, participate in uterine ECM remodeling throughout pregnancy and parturition. However, their loss-of-function effect is unknown. Here, we determined the result of eliminating Mmp2 and/or Mmp9 on parturition in vivo, using single- and double-knockout (dKO) mice. The dystocia rates were measured in each genotype, and uterine tissue was collected from nulliparous synchronized females at the ages of 2, 4, 9 and 12 months. Very high percentages of dystocia (40-55%) were found in the Mmp2-/- and dKO females, contrary to the Mmp9-/- and wild-type females. The histological analysis of the uterus and cervix revealed that Mmp2-/- tissues undergo marked structural alterations, including highly enlarged myometrial, endometrial and luminal cavity. Increased collagen deposition was also demonstrated, suggesting a mechanism of extensive fibrosis in the Mmp2-/- myometrium, which may result in dystocia. Overall, this study describes a new role for MMP2 in myometrium remodeling during mammalian parturition process, highlighting a novel cause for dystocia due to a loss in MMP2 activity in the uterine tissue.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Heterotypic Cell Culture from Mouse Bone Marrow under Simulated Microgravity: Lessons for Stromal Lineage Functions

Muscle and skeleton structures are considered most susceptible to negative factors of spaceflights, namely microgravity. Three-dimensional clinorotation is a ground-based simulation of microgravity. It provides an opportunity to elucidate the effects of microgravity at the cellular level. The extracellular matrix (ECM) content, transcriptional profiles of genes encoding ECM and remodelling molecules, and secretory profiles were investigated in a heterotypic primary culture of bone marrow cells after 14 days of 3D clinorotation. Simulated microgravity negatively affected stromal lineage cells, responsible for bone tissue formation. This was evidenced by the reduced ECM volume and stromal cell numbers, including multipotent mesenchymal stromal cells (MSCs). ECM genes encoding proteins responsible for matrix stiffness and cell-ECM contacts were downregulated. In a heterotypic population of bone marrow cells, the upregulation of genes encoding ECM degrading molecules and the formation of a paracrine profile that can stimulate ECM degradation, may be mechanisms of osteodegenerative events that develop in real spaceflight.

Expression dynamics of metalloproteinases during mandibular bone formation: association with Myb transcription factor

As the dentition forms and becomes functional, the alveolar bone is remodelled. Metalloproteinases are known to contribute to this process, but new regulators are emerging and their contextualization is challenging. This applies to Myb, a transcription factor recently reported to be involved in bone development and regeneration. The regulatory effect of Myb on Mmps expression has mostly been investigated in tumorigenesis, where Myb impacted the expression of Mmp1, Mmp2, Mmp7, and Mmp9. The aim of this investigation was to evaluate the regulatory influence of the Myb on Mmps gene expression, impacting osteogenesis and mandibular bone formation. For that purpose, knock-out mouse model was used. Gene expression of bone-related Mmps and the key osteoblastic transcription factors Runx2 and Sp7 was analysed in Myb knock-out mice mandibles at the survival limit. Out of the metalloproteinases under study, Mmp13 was significantly downregulated. The impact of Myb on the expression of Mmp13 was confirmed by the overexpression of Myb in calvarial-derived cells causing upregulation of Mmp13. Expression of Mmp13 in the context of other Mmps during mandibular/alveolar bone development was followed in vivo along with Myb, Sp7 and Runx2. The most significant changes were observed in the expression of Mmp9 and Mmp13. These MMPs and MYB were further localized in situ by immunohistochemistry and were identified in pre/osteoblastic cells as well as in pre/osteocytes. In conclusion, these results provide a comprehensive insight into the expression dynamics of bone related Mmps during mandibular/alveolar bone formation and point to Myb as another potential regulator of Mmp13.

Proteomic Analysis of Mesenchymal Stromal Cells Secretome in Comparison to Leukocyte- and Platelet-Rich Fibrin

Secretomes of mesenchymal stromal cells (MSCs) are emerging as a novel growth factor (GF)-based strategy for periodontal and bone regeneration. The objective of this study was to compare the secretome of human bone marrow MSC (BMSC) to that of leukocyte- and platelet-rich fibrin (L-PRF), an established GF-based therapy, in the context of wound healing and regeneration. Conditioned media from human BMSCs (BMSC-CM) and L-PRF (LPRF-CM) were subjected to quantitative proteomic analysis using liquid chromatography with tandem mass spectrometry. Global profiles, gene ontology (GO) categories, differentially expressed proteins (DEPs), and gene set enrichment (GSEA) were identified using bioinformatic methods. Concentrations of selected proteins were determined using a multiplex immunoassay. Among the proteins identified in BMSC-CM (2157 proteins) and LPRF-CM (1420 proteins), 1283 proteins were common. GO analysis revealed similarities between the groups in terms of biological processes (cellular organization, protein metabolism) and molecular functions (cellular/protein-binding). Notably, more DEPs were identified in BMSC-CM (n = 550) compared to LPRF-CM (n = 118); these included several key GF, cytokines, and extracellular matrix (ECM) proteins involved in wound healing. GSEA revealed enrichment of ECM (especially bone ECM)-related processes in BMSC-CM and immune-related processes in LPRF-CM. Similar trends for intergroup differences in protein detection were observed in the multiplex analysis. Thus, the secretome of BMSC is enriched for proteins/processes relevant for periodontal and bone regeneration. The in vivo efficacy of this therapy should be evaluated in future studies.

Extracellular vesicles derived from bone marrow mesenchymal stem cells loaded on magnetic nanoparticles delay the progression of diabetic osteoporosis via delivery of miR-150-5p

Extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) are emerged as carriers of therapeutic targets against bone disorders, yet its isolation and purification are limited with recent techniques. Magnetic nanoparticles (MNPs) can load EVs with a unique targeted drug delivery system. We constructed gold-coated magnetic nanoparticles (GMNPs) by decorating the surface of the Fe3O4@SiO2 core and a silica shell with poly(ethylene glycol) (PEG)-aldehyde (CHO) and examined the role of BMSC-EVs loaded on GMNPs in diabetic osteoporosis (DO). The osteoporosis-related differentially expressed miR-150-5p was singled out by microarray analysis. DO models were then established in Sprague-Dawley rats by streptozotocin injection, where poor expression of miR-150-5p was validated in the bone tissues. Next, GMNPE was prepared by combining GMNPs with anti-CD63, after which osteoblasts were co-cultured with the GMNPE-BMSC-EVs. The re-expression of miR-150-5p facilitated osteogenesis in osteoblasts. GMNPE could promote the enrichment of EVs in the bone tissues of DO rats. BMSC-EVs delivered miR-150-5p to osteoblasts, where miR-150-5p targeted MMP14 and consequently activated Wnt/β-catenin pathway. This effect contributed to the enhancement of osteoblast proliferation and maturation. Furthermore, GMNPE enhanced the EV-based delivery of miR-150-5p to regulate the MMP14/Wnt/β-catenin axis, resulting in promotion of osteogenesis. Overall, our findings suggest the potential of GMNP-BMSC-EVs to strengthen osteoblast proliferation and maturation in DO, showing promise as an appealing drug delivery strategy against DO. 1. GMNPs-BMSCs-EVs-miR-150-5p promotes the osteogenesis of DO rats. 2. miR-150-5p induces osteoblast proliferation and maturation by targeting MMP14. 3. Inhibition of MMP14 activates Wnt/β-catenin and increases osteogenesis. 4. miR-150-5p activates the Wnt/β-catenin pathway by downregulating MMP14.

Application of stem cells in regeneration medicine

Regeneration is a complex process affected by many elements independent or combined, including inflammation, proliferation, and tissue remodeling. Stem cells is a class of primitive cells with the potentiality of differentiation, regenerate with self-replication, multidirectional differentiation, and immunomodulatory functions. Stem cells and their cytokines not only inextricably linked to the regeneration of ectodermal and skin tissues, but also can be used for the treatment of a variety of chronic wounds. Stem cells can produce exosomes in a paracrine manner. Stem cell exosomes play an important role in tissue regeneration, repair, and accelerated wound healing, the biological properties of which are similar with stem cells, while stem cell exosomes are safer and more effective. Skin and bone tissues are critical organs in the body, which are essential for sustaining life activities. The weak repairing ability leads a pronounced impact on the quality of life of patients, which could be alleviated by stem cell exosomes treatment. However, there are obstacles that stem cells and stem cells exosomes trough skin for improved bioavailability. This paper summarizes the applications and mechanisms of stem cells and stem cells exosomes for skin and bone healing. We also propose new ways of utilizing stem cells and their exosomes through different nanoformulations, liposomes and nanoliposomes, polymer micelles, microspheres, hydrogels, and scaffold microneedles, to improve their use in tissue healing and regeneration.

Exploring the role and mechanism of Fuzi decoction in the treatment of osteoporosis by integrating network pharmacology and experimental verification

BACKGROUND

Fuzi decoction (FZD), a traditional Chinese medicine formula, was used to treat musculoskeletal diseases by warming channels, strengthening yang and dispelling pathogenic cold and dampness. In clinical practice, FZD has been used to treat rheumatoid arthritis and osteoarthritis. It alleviated osteoarticular disorders through ameliorating the degradation of cartilage and improving meniscal damage in osteoarthritis, while its roles and mechanisms in the treatment of bone loss diseases remain unclear. This study aims to investigate the underlying mechanisms of FZD in treating osteoporosis using an integrative method of network pharmacology and experimental study.

METHODS

In this study, network pharmacology was used to predict the core targets and potential pathways of the bioactive ingredients of FZD to attenuate osteoporosis. Molecular docking was performed to evaluate the interactions between core compounds and key targets. In addition, both cell and animal experiments were carried out to validate the role and potential mechanism in treating osteoporosis.

RESULTS

In the present study, data revealed that kaempferol, beta-sitosterol, stigmasterol, fumarine, and (+)-catechin may be the primary bioactive ingredients of FZD in the treatment of osteoporosis, which were closely associated with the osteoporosis-related targets. And the KEGG results indicated that the NF-κB pathway was closely associated with the function of FZD in treating osteoporosis. In addition, in vivo demonstrated that FZD ameliorated osteoporosis. In vitro experiments showed that the pro-apoptotic factors indicators including CASP3 and BAX were decreased by FZD and the anti-apoptotic factor BCL2 was increased by FZD. In addition, FZD significantly suppressed the osteoclast differentiation in culture and the expression levels of osteoclast-related genes including TRAF6, CTSK, and MMP9. And the NF-κB pathway was confirmed, via in vitro experiment, to be involved in osteoclast differentiation.

CONCLUSIONS

This study demonstrated that FZD played a pivotal role in suppressing the osteoclast differentiation via regulating the NF-κB pathway, indicating that FZD could be a promising antiosteoporosis drug and deserve further investigation.

Unearths IFNB1 immune infiltrates in SOP-related ossification of ligamentum flavum pathogenesis

Background

Ossification of ligamentum flavum (OLF) is a hidden, indolent disease condition with variable unexplained etiology and pathology. Growing evidences show a correlation between senile osteoporosis (SOP) and OLF, but the fundamental relationship between SOP and OLF remains unclear. Therefore, the purpose of this work is to investigate unique SOP-related genes and their potential functions in OLF.

Methods

Gene Expression Omnibus (GEO) database was utilized to gather the mRNA expression data (GSE106253) and then analyzed by R software. A variety of methods, including ssGSEA, machine learning (LASSO and SVM-RFE), GO and KEGG enrichment, PPI network, transcription factor enrichment analysis (TFEA), GSEA and xCells were employed to verified the critical genes and signaling pathways. Furthermore, ligamentum flavum cells were cultured and used in vitro to identify the expression of the core genes.

Results

The preliminary identification of 236 SODEGs revealed their involvement in BP pathways associated with ossification, inflammation, and immune response, including the TNF signaling pathway, PI3K/AKT signaling pathway and osteoclast differentiation. Four down-regulated genes (SERPINE1, SOCS3, AKT1, CCL2) and one up-regulated gene (IFNB1) were among the five hub SODEGs that were validated. Additionally, they were performed by ssGSEA and xCell to show the relationship of immune cells infiltrating in OLF. The most fundamental gene, IFNB1, which was only found in the classical ossification- and inflammation-related pathways, suggested that it may affect OLF via regulating the inflammatory response. In vitro experiment, we found that IFNB1 expression was dramatically higher in cells cocultured with osteogenic induction than in controls.

Conclusion

As far as we are concerned, this is the first observation using transcriptome data mining to reveal distinct SOP-related gene profiles between OLF and normal controls. Five hub SODEGs were ultimately found using bioinformatics algorithms and experimental verification. These genes may mediate intricate inflammatory/immune responses or signaling pathways in the pathogenesis of OLF, according to the thorough functional annotations. Since IFNB1 was discovered to be a key gene and was connected to numerous immune infiltrates in OLF, it is possible that IFNB1 expression has a substantial impact on the pathogenesis of OLF. Our research will give rise to new possibilities for potential therapeutics that target SOP reverent genes and immune-associated pathways in OLF.

Naringenin and proanthocyanidins pre-treatment decreases synthesis and activity of gelatinases induced by zoledronic acid in a dental implant surface in vitro model

OBJECTIVE

To assess the effects of pre-treatment with proanthocyanidins (PA) flavonoids, from grape seed extract, and synthetic naringenin (NA) on the synthesis of matrix metalloproteinases (MMPs) gelatinases and their tissue inhibitors (TIMPs), as well as the gelatinolytic activity of MMPs by human gingival fibroblasts (HGF) and osteoblasts (Ob) exposed to zoledronic acid (ZA) in a dental implant surface in vitro model.

DESIGN

The highest non-cytotoxic concentrations of NA and PA were determined for HGF (10 μg/mL; defined by previous study) and Ob (0.5 μg/mL; defined by prestoBlue assay). Then, HFG and Ob were individually seeded onto titanium discs, and after 24 h, cells were pre-treated (or not) with NA or PA, followed (or not) by exposure to ZA. Next, MMP-2, MMP-9, TIMP-1, TIMP-2 synthesis (ELISA), and gelatinolytic activity (in situ zymography) was evaluated. Data were analyzed by one-way ANOVA and Tukey tests (α = 0.05).

RESULTS

ZA treatment increased the synthesis (p < 0.05) and activity of MMPs; flavonoids pre-treatment controlled ZA-induced gelatinolytic effects, down-regulating MMPs synthesis (p < 0.05) and activity by HGF and Ob. For HGF, NA and PA pre-treatment did not up-regulate TIMP synthesis after ZA exposure (p > 0.05); for Ob, TIMP-2 was up-regulated (p < 0.05) by flavonoids, followed by ZA.

CONCLUSIONS

NA and PA pre-treatment provides interesting results in the modulation of ZA deleterious effects, down-regulating MMP-2 and MMP-9 synthesis and activity by HGF and Ob and up-regulating TIMP-2 by Ob.

Extracellular matrix-regulator MMPA is required for the orderly proliferation of neoblasts and differentiation of ectodermal progenitor cells in the planarian Dugesia japonica

Matrix metalloproteinases (MMPs) are members of a family of zinc-dependent metallopeptidase proteins that are widely found in plants, animals, and microorganisms. As the regulators of the extracellular matrix and basement membrane, MMPs play an important role in embryogenesis, development, innate immunity, and regeneration. However, the function of MMP family in planarian, a model for regeneration research, is still ambiguous. Here, we cloned 5 MMPs genes from Dugesia japonica and found that DjMMPA was associated with the process of regeneration, neoblasts cell maintenance confusion and destruction. Loss of DjMMPA led to homeostasis confusion and eventually death, owing to neoblasts proliferation disorder. Additionally, DjMMPA RNAi-treated animals had impaired regeneration after amputation. Furthermore, knockdown of DjMMPA had noticeable defects in cell differentiation of ectoderm, especially in eyes and neural progenitor cells, possibly by inhibiting Wnt signaling. Our results suggest that extracellular matrix-regulator MMPA is required for the orderly proliferation of neoblasts and differentiation of ectodermal progenitor cells in the planarian, which provide valuable information for further explorations into the molecular mechanism of MMPS, stem cells, and regeneration.

Berberine regulates bone metabolism in apical periodontitis by remodelling the extracellular matrix

OBJECTIVES

The objectives of this study were to explore the role and related mechanism of berberine in repairing bone destruction in apical periodontics (AP).

MATERIALS AND METHODS

AP was established in 14 of 21 male Wistar rats (four weeks of age; 70-80 g) for 3 weeks. The canals were cleaned and administered berberine (2 mg/ml; n = 7) or calcium hydroxide (100 mg/ml; control; n = 7), followed by glass ionomer cement sealing. After 3 weeks, specimen collection followed by micro-computed tomography (μ-CT) and histological staining was performed, including haematoxylin and eosin staining, Masson's trichrome staining, tartrate-resistant acid phosphatase staining, immunohistochemistry and immunofluorescence histochemistry.

RESULTS

μ-CT showed that AP lesion volume reduced in the berberine group. Histopathology showed that berberine decreased the activity and number of osteoclasts but increased the expression of proteins related to osteoblast differentiation, including alkaline phosphatase and osterix. The immune cell, T cell, dendritic cell and macrophage counts were significantly decreased in the berberine group. In the berberine group, the expression of extracellular matrix-degraded proteases, metalloproteinases, was decreased; however, that of extracellular matrix-stable proteases, lysyl oxidases, was increased.

CONCLUSIONS

Berberine controlled the inflammatory response and regulated bone metabolism in AP by reducing metalloproteinase expression and increasing lysyl oxidases expression.

Role of cathepsin D induced by Porphyromonas gingivalis lipopolysaccharide in periodontitis

Periodontitis is an inflammatory disease of tooth-supporting tissues caused by oral bacteria. Periodontal ligament loss and alveolar bone destruction occur in progressive periodontitis. Since gingival crevicular fluids (GCF) reflects the inflammatory environment of the periodontal pocket, it is a very important specimen for developing targets for periodontitis diagnosis. An antibody array was performed using GCF collected from healthy participants and patients with periodontitis to identify the proteolytic enzymes involved in periodontitis. Of 21 targets on the antibody array membrane, kallikrein 6 (KLK6), kallikrein 10 (KLK10), cathepsin A (CathA), and cathepsin D (CathD) showed higher levels in periodontitis GCF than in GCF from healthy participants. Lipopolysaccharide stimulation of Porphyromonas gingivalis (PG-LPS) in immortalized gingival fibroblasts only increased CathD protein levels among the four targets. The substrate cleavage activity of CathD was increased in PG-LPS-treated immortalized gingival fibroblast extract. The PG-LPS-induced substrate cleavage effect was abolished by the CathD inhibitor pepstatin A. Osteoclast formation was promoted by treatment with conditioned media from PG-LPS- treated immortalized gingival fibroblasts but inhibited by the CathD inhibitor pepstatin A. These results suggest that PG-LPS affected the osteoclast formation process by increasing CathD expression in cells around the alveolar bone, thereby participating in periodontitis progression.

Decreased serum MMP-9 levels in patients with nontraumatic osteonecrosis of the femoral head

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) are involved in the pathological mechanism of osteonecrosis of the femoral head (ONFH). This study aimed to investigate the relationship of serum MMP-9, TIMP-1, and the MMP-9/TIMP-1 ratio with disease severity in patients with nontraumatic ONFH.

METHODS

Serum levels of MMP-9 and TIMP-1 among 102 nontraumatic ONFH patients and 96 healthy individuals were determined by enzyme-linked immunosorbent assay (ELISA). Imaging severity was determined using the FICAT classification system. The Harris hip score (HHS) and visual analogue scale (VAS) were used to evaluate clinical progress. The correlations of serum MMP-9 and TIMP-1 levels with imaging severity and clinical progress was evaluated statistically. The diagnostic value of MMP-9 for NONFH disease severity was evaluated by examining receiver operating characteristic (ROC) curves.

RESULTS

The serum MMP-9 levels and the MMP-9/TIMP-1 ratio were significantly increased in patients with ONFH compared to normal controls, and TIMP-1 levels did not differ between the two groups. Serum MMP-9 levels and the MMP-9/TIMP-1 ratio were positively correlated with FICAT stage and VAS and were negatively correlated with the HHS score. The ROC curve results indicated that MMP-9 could be used as a potential marker of nontraumatic ONFH imaging progression.

CONCLUSIONS

We hypothesize that increased MMP-9 expression and an imbalance in the MMP-9/TIMP-1 ratio play a role in the development of ONFH and are correlate with the severity of ONFH. The determination of MMP-9 can be a useful tool to assess the severity of the disease in patients with nontraumatic ONFH.

Unusual Suspects: Bone and Cartilage ECM Proteins as Carcinoma Facilitators

The extracellular matrix (ECM) is the complex three-dimensional network of fibrous proteins and proteoglycans that constitutes an essential part of every tissue to provide support for normal tissue homeostasis. Tissue specificity of the ECM in its topology and structure supports unique biochemical and mechanical properties of each organ. Cancers, like normal tissues, require the ECM to maintain multiple processes governing tumor development, progression and spread. A large body of experimental and clinical evidence has now accumulated to demonstrate essential roles of numerous ECM components in all cancer types. Latest findings also suggest that multiple tumor types express, and use to their advantage, atypical ECM components that are not found in the cancer tissue of origin. However, the understanding of cancer-specific expression patterns of these ECM proteins and their exact roles in selected tumor types is still sketchy. In this review, we summarize the latest data on the aberrant expression of bone and cartilage ECM proteins in epithelial cancers and their specific functions in the pathogenesis of carcinomas and discuss future directions in exploring the utility of this selective group of ECM components as future drug targets.

Dysregulation of metalloproteinases in spinal ligament degeneration

PURPOSE

Degenerative changes in the spinal ligaments, such as hypertrophy or ossification, are important pathophysiological mechanisms of secondary spinal stenosis and neurological compression. Extracellular matrix (ECM) remodeling is one of the major pathological changes in ligament degeneration, and in this remodeling, ECM proteinase-mediated degradation of elastin and collagen plays a vital role. Zinc-dependent endopeptidases, including matrix metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs), and ADAMs with thrombospondin-1 motifs (ADAMTSs) are key factors in ECM remodeling. This review aims to elucidate the underlying mechanisms of these metalloproteinases in the initiation and progression of spinal ligament degeneration.

METHODS

We clarify current literature on the dysregulation of MMPs/ADAMs/ADAMTS and their endogenous inhibitors in degenerative spinal ligament diseases. In addition, some instructive information was excavated from the raw data of the relevant high-throughput analysis.

RESULTS AND CONCLUSIONS

The dysregulation of metalloproteinases and their endogenous inhibitors may affect ligament degeneration by involving several interrelated processes, represented by ECM degradation, fibroblast proliferation, and osteogenic differentiation. Antagonists of the key targets of the processes may in turn ease ligament degeneration.

Compressed Prostate Cancer Cells Decrease Osteoclast Activity While Enhancing Osteoblast Activity In Vitro

Once prostate cancer cells metastasize to bone, they perceive approximately 2 kPa compression. We hypothesize that 2 kPa compression stimulates the epithelial-to-mesenchymal transition (EMT) of prostate cancer cells and alters their production of paracrine signals to affect osteoclast and osteoblast behavior. Human DU145 prostate cancer cells were subjected to 2 kPa compression for 2 days. Compression decreased expression of 2 epithelial genes, 5 out of 13 mesenchymal genes, and increased 2 mesenchymal genes by DU145 cells, as quantified by qPCR. Conditioned medium (CM) of DU145 cells was added to human monocytes that were stimulated to differentiate into osteoclasts for 21 days. CM from compressed DU145 cells decreased osteoclast resorptive activity by 38% but did not affect osteoclast size and number compared to CM from non-compressed cells. CM was also added to human adipose stromal cells, grown in osteogenic medium. CM of compressed DU145 cells increased bone nodule production (Alizarin Red) by osteoblasts from four out of six donors. Compression did not affect IL6 or TNF-α production by PC DU145 cells. Our data suggest that compression affects EMT-related gene expression in DU145 cells, and alters their production of paracrine signals to decrease osteoclast resorptive activity while increasing mineralization by osteoblasts is donor dependent. This observation gives further insight in the altered behavior of PC cells upon mechanical stimuli, which could provide novel leads for therapies, preventing bone metastases.

Evaluating material-driven regeneration in a tissue engineered human in vitro bone defect model

Advanced in vitro human bone defect models can contribute to the evaluation of materials for in situ bone regeneration, addressing both translational and ethical concerns regarding animal models. In this study, we attempted to develop such a model to study material-driven regeneration, using a tissue engineering approach. By co-culturing human umbilical vein endothelial cells (HUVECs) with human bone marrow-derived mesenchymal stromal cells (hBMSCs) on silk fibroin scaffolds with in vitro critically sized defects, the growth of vascular-like networks and three-dimensional bone-like tissue was facilitated. After a model build-up phase of 28 days, materials were artificially implanted and HUVEC and hBMSC migration, cell-material interactions, and osteoinduction were evaluated 14 days after implantation. The materials physiologically relevant for bone regeneration included a platelet gel as blood clot mimic, cartilage spheres as soft callus mimics, and a fibrin gel as control. Although the in vitro model was limited in the evaluation of immune responses, hallmarks of physiological bone regeneration were observed in vitro. These included the endothelial cell chemotaxis induced by the blood clot mimic and the mineralization of the soft callus mimic. Therefore, the present in vitro model could contribute to an improved pre-clinical evaluation of biomaterials while reducing the need for animal experiments.

MicroRNA Modulation during Orthodontic Tooth Movement: A Promising Strategy for Novel Diagnostic and Personalized Therapeutic Interventions

The Orthodontic Tooth Movement (OTM) is allowed through a mediated cell/tissue mechanism performed by applying a force or a pair of forces on the dental elements, and the tooth movement is a fundamental requirement during any orthodontic treatment. In this regard, it has been widely shown that each orthodontic treatment has a minimum duration required concerning numerous factors (age, patient compliance, type of technique used, etc.). In this regard, the aim of the following revision of the literature is to give readers a global vision of principal microRNAs (miRNAs) that are most frequently associated with OTM and their possible roles. Previously published studies of the last 15 years have been considered in the PubMed search using "OTM" and "miRNA" keywords for the present review article. In vitro and in vivo studies and clinical trials were mainly explored. Correlation between OTM and modulation of several miRNAs acting through post-transcriptional regulation on target genes was observed in the majority of previous studied. The expression analysis of miRNAs in biological samples, such as gingival crevicular fluid (GCF), can be considered a useful tool for novel diagnostic and/or prognostic approaches and for new personalized orthodontic treatments able to achieve a better clinical response rate. Although only a few studies have been published, the data obtained until now encourage further investigation of the role of miRNA modulation during orthodontic treatment. The aim of this study is to update the insights into the role and impact of principal micro-RNAs (miRNAs) that are most frequently associated during OTM.

Fibrinolysis Regulation: A Promising Approach to Promote Osteogenesis

Soon after bone fracture, the initiation of the coagulation cascade results in the formation of a blood clot, which acts as a natural material to facilitate cell migration and osteogenic differentiation at the fracture site. The existence of hematoma is important in early stage of bone healing, but the persistence of hematoma is considered harmful for bone regeneration. Fibrinolysis is recently regarded as a period of critical transition in angiogenic-osteogenic coupling, it thereby is vital for the complete healing of the bone. Moreover, the enhanced fibrinolysis is proposed to boost bone regeneration through promoting the formation of blood vessels, and fibrinolysis system as well as the products of fibrinolysis also play crucial roles in the bone healing process. Therefore, the purpose of this review is to elucidate the fibrinolysis-derived effects on osteogenesis and summarize the potential approaches-improving bone healing by regulating fibrinolysis, with the purpose to further understand the integral roles of fibrinolysis in bone regeneration and to provide theoretical knowledge for potential fibrinolysis-related osteogenesis strategies. Impact statement Fibrinolysis emerging as a new and viable therapeutic intervention to be contained within osteogenesis strategies, however to now, there have been no review articles which collates the information between fibrinolysis and osteogenesis. This review, therefore, focusses on the effects that fibrinolysis exerts on bone healing, with a purpose to provide theoretical reference to develop new strategies to modulate fibrinolysis to accelerate fibrinolysis thus enhancing bone healing.

Cell-free immunomodulatory biomaterials mediated in situ periodontal multi-tissue regeneration and their immunopathophysiological processes

Cell-free biomaterials-inducing endogenous in situ multi-tissue regeneration is very challenging and applying advanced immunomodulatory biomaterials can be an effective strategy to overcome it. In-depth knowledge of the immunopathophysiological mechanisms should be acquired before applying such an immunomodulation strategy. In this study, we implanted different immunoregulatory cell-free biomaterials into periodontal multi-tissue defects and showed that the outcome of multi-tissue regeneration is closely regulated by the immune reaction. The underlying immunopathophysiological processes, including the blood clotting response and fibrinoid necrosis, innate and adaptive immune response, local and systemic immune reaction, growth factors release, and stem cells recruitment, were revealed. The implantation of biomaterials with anti-inflammatory properties could direct the immunopathophysiological process and make it more favorable for in situ multi-tissue regeneration, ultimately enabling the regeneration of the periodontal ligament, the acellular cementum matrix, and the alveolar bone in the periodontium. These findings further confirm the effectiveness of immunomodulatory based strategy and the unveiling of their immunopathophysiological processes could provide some favorable theoretical bases for the development of advanced cell-free immunomodulatory multi-tissue regenerative biomaterials.

Utility of Matrix Metalloproteinases in the Diagnosis, Monitoring and Prognosis of Ovarian Cancer Patients

Ovarian cancer is one of the most common gynecologic malignancies. It is characterized by a high mortality rate, which is mainly due to the asymptomatic course of the disease. In light of the high mortality rate and increasing morbidity, new diagnostic methods are being explored to enable earlier detection, better monitoring, and improved prognosis. Such diagnostic methods include the assessment of tumor markers in various biological samples. Among the markers currently being investigated, extracellular matrix metalloproteinases (MMPs) are of particular interest. The objective of this article was to compile the existing knowledge of MMPs in ovarian cancer patients and to describe their potential diagnostic utility. Additionally, this article provides an overview of the symptoms, complications, and risk factors associated with ovarian cancer and the role of MMPs in physiology and pathology. Preliminary results indicate that tissue expression and blood and body fluid levels of MMPs may be different in ovarian cancer patients than in healthy women. The expression and concentration of individual MMPs have been shown to be correlated with cancer stage and disease severity. In addition, the preliminary value of some of these enzymes in predicting prognosis is discussed. However, as the amount of data is limited, more studies are needed to fully evaluate the potential function of individual MMPs in ovarian cancer patients. Based on the knowledge gathered for this article, it seems that MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-13, are tentatively the most useful. A thorough evaluation of their utility as modern biomarkers in ovarian cancer requires further investigation.

The role of proteoglycan form of DMP1 in cranial repair

Background

The cranial region is a complex set of blood vessels, cartilage, nerves and soft tissues. The reconstruction of cranial defects caused by trauma, congenital defects and surgical procedures presents clinical challenges. Our previous data showed that deficiency of the proteoglycan (PG) form of dentin matrix protein 1 (DMP1-PG) could lead to abnormal cranial development. In addition, DMP1-PG was highly expressed in the cranial defect areas. The present study aimed to investigate the potential role of DMP1-PG in intramembranous ossification in cranial defect repair.

Methods

Mouse cranial defect models were established by using wild- type (WT) and DMP1-PG point mutation mice. Microcomputed tomography (micro-CT) and histological staining were performed to assess the extent of repair. Immunofluorescence assays and real-time quantitative polymerase chain reaction (RT‒qPCR) were applied to detect the differentially expressed osteogenic markers. RNA sequencing was performed to probe the molecular mechanism of DMP1-PG in regulating defect healing.

Results

A delayed healing process and an abnormal osteogenic capacity of primary osteoblasts were observed in DMP1-PG point mutation mice. Furthermore, impaired inflammatory signaling pathways were detected by using RNA transcription analysis of this model.

Conclusions

Our data indicate that DMP1-PG is an indispensable positive regulator during cranial defect healing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-022-00443-4.

Transcriptomic analysis reveals genetic factors regulating early steroid-induced osteonecrosis of the femoral head

The present study aimed to explore the signaling pathways involved in development of early steroid-induced osteonecrosis of the femoral head (SONFH) and identify diagnostic biomarkers regulating peripheral blood in SONFH patients. We downloaded transcriptome data and identified differentially expressed genes (DEGs) using the R software. We used ClusterProfiler to perform enrichment analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, and analyzed protein-protein interactions using the STRING database. Network X was used to visualize the networks in Python. A total of 584 DEGs were identified, of which 294 and 290 were upregulated and downregulated, respectively. Enrichment analysis showed that the DEGs were mainly involved in red blood cell differentiation, cell protein catabolism, gas transportation, activation of myeloid leukocytes, phagocytosis, and inflammatory response. Pathway analysis revealed that these DEGs were involved in regulation of mitophagy-animal, human T-cell leukemia virus-1 infection, Forkhead box O, phagocytosis, osteoclast differentiation, and cytokine-cytokine receptor interaction. Quantitative real-time polymerase chain reaction results were consistent with findings from protein-protein interaction network analysis. Several genes, including peroxiredoxin 2, haptoglobin, matrix metallopeptidase 8, formyl peptide receptor 2, and integrin subunit alpha X, promote SONFH occurrence by regulating the redox, inflammatory response, and osteoblast and osteoclast structure and function pathways. They may be important targets for designing approaches for early diagnosis and treatment of SONFH.

Osteogenic Efficacy of Human Trophoblasts-Derived Conditioned Medium on Mesenchymal Stem Cells

Trophoblasts play an important role in the regulation of the development and function of the placenta. Our recent study demonstrated the skin regeneration capacity of trophoblast-derived extracellular vesicles (EV). Here, we aimed to determine the potential of trophoblast-derived conditioned medium (TB-CM) in enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). We found that TB-CM promoted the osteogenic differentiation of MSCs in a dose-dependent manner. Furthermore, it inhibited adipogenesis of MSCs. We also found that the primary trophoblast-derived conditioned medium (PTB-CM) significantly enhanced the proliferation and osteogenic differentiation of human MSCs. Our study demonstrated the regulatory mechanisms underlying the TB-CM-induced osteogenesis in MSCs. An upregulation of genes associated with cytokines/chemokines was observed. The treatment of MSCs with TB-CM stimulated osteogenesis by activating several biological processes, such as mitogen-activated protein kinase (MAPK) and bone morphogenetic protein 2 (BMP2) signaling. This study demonstrated the proliferative and osteogenic efficacies of the trophoblast-derived secretomes, suggesting their potential for use in clinical interventions for bone regeneration and treatment.

Bone Health Management in the Continuum of Prostate Cancer Disease

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Loss of MMP-27 Predicts Mandibular Bone Invasion in Oral Squamous Cell Carcinoma

Simple Summary

The growth of oral squamous cell carcinoma into the mandible poses significant challenges to head and neck surgery. The resulting need for extensive procedures has a decisive influence on subsequent esthetics and function and therefore also on the patient’s quality of life. The molecular mechanism behind this remains obscure to date. Hence, we investigated the influence of MMP-27, Osteoprotegerin and RANKL, three proteins with importance in bone remodeling. The results showed that tumors exhibited less bone-invasive behavior in the presence of MMP-27. This may be an incentive for further studies to elucidate the molecular mechanisms of mandibular bone invasion in OSCC.

Abstract

Invasion of the mandibular bone is frequent in oral squamous cell carcinoma (OSCC), which often results in extensive ablative and reconstructive procedures for the patient. The purpose of this single-center, retrospective study was to identify and evaluate potential biomarkers and risk factors for bone invasion in OSCC. Initially, in silico gene expression analysis was performed for different HNSCC tumor T-stages to find factors associated with invasive (T4a) tumor growth. Afterwards, the protein expression of bone-metabolizing MMP-27, TNFRSF11B (Osteoprotegerin, OPG), and TNFSF11 (RANKL) was investigated via Tissue Microarrays (TMAs) for their impact on mandibular bone invasion. TMAs were assembled from the bone–tumor interface of primary OSCCs of the floor of the mouth and gingiva from 119 patients. Sixty-four carcinomas with patho-histological jaw invasion (pT4a) were compared to 55 carcinomas growing along the mandible without invasion (pT2, pT3). Tissue samples were additionally evaluated for patterns of invasion using the WPOI grading system. Statistical analysis of in silico data revealed decreased MMP-27 mRNA expression to be strongly associated with the pT4a-stage in OSCC, indicating invasive tumor growth with infiltration of adjacent anatomical structures. Our own clinico-pathological data on OSCCs presented a significant decrease of MMP-27 in tumors invading the nearby mandible (pT4a), compared to pT2 and pT3 tumors without bone invasion. Loss of MMP27 evolved as the strongest predictor of mandibular bone invasion in binary logistic regression analysis. To our knowledge, this is the first study investigating the role of MMP-27 expression in OSCC and demonstrating the importance of the loss of MMP-27 in mandibular bone invasion.

Identification of Novel Compound Heterozygous Variants of MMP9 in Fetus With Metaphyseal Anadysplasia Type 2

Matrix metalloproteinase 9 (MMP9) is an important member of the matrix metalloproteinase family and plays a key role in balancing extracellular matrix proteins. Studies have shown that the homozygous mutations in MMP9 can lead to metaphyseal anadysplasia type 2 (MANDP2, OMIM#613073). The clinical phenotype of this disease is limited and there were only five reported cases of MANDP2 associated with homozygous MMP9 mutations from three families. In this study, we described a case of a fetus with skeletal system malformation. The main clinical manifestations include the short bilateral femur, absence of right fibula, and curved ipsilateral tibia with short length. Importantly, two novel compound heterozygous variants of the MMP9 gene (NM_004,994.3: c.151C &gt; T and c.929del) were found through the trio whole exome sequencing and Sanger sequencing. This is the first report that identified the compound heterozygous variants of the MMP9 gene associated with metaphyseal dysplasia type 2.

Acupuncture for Knee Osteoarthritis: A Systematic Review of Randomized Clinical Trials with Meta-Analyses and Trial Sequential Analyses

Background

Knee osteoarthritis (KOA) can cause chronic pain and seriously affect the quality of patient lives. The continued emergence of high-quality RCTS requires us to update the quality of evidence. This study aims to evaluate the efficacy of acupuncture for KOA patients and calculate the required information size (RIS) to determine whether further clinical studies are required.

Methods

We searched PubMed, Embase, WOS, CBM, CNKI, VIP, WHO ICTRP, ChiCTR, and Grey literature to collect randomized controlled trials (RCTs) of acupuncture for KOA from inception to December 2021. A meta-analysis was performed according to the Cochrane systematic review method by using Review Manager 5.4 and TSA 0.9.5.10 beta, and GRADE was used to evaluate the quality of the evidence. Trial sequential analysis was used to control random errors and calculate the required information size.

Results

Eleven RCTs with 2484 patients were included in our meta-analysis, meeting the inclusion criteria for the meta-analysis. The meta-analysis indicated that acupuncture had beneficial effect on knee osteoarthritis in reducing pain [n = 2387; SMD = -0.12, 95% CI (-0.20, -0.04); I 2 = 0%] and improved patients function activities [n = 2408; MD = -1.25, 95% CI (-1.97, -0.53); I 2 = 0%], but true acupuncture showed no significant effect in relieve patient's stiffness [n = 1337; MD = -0.07, 95% CI (-0.30, 0.15); I 2 = 0%]. We pooled the studies which found no significant difference in improving the quality life of mental [n = 1462; SMD = 0.02, 95% CI (-0.23, 0.27); I 2 = 78%] and patients physical health (SF-36 or SF-12) [n = 1745; SMD = 1.01, 95% CI (-0.08, 2.11); I 2 = 0%] compared with sham acupuncture. The pain and function TSA graphs indicated that cumulative Z-curves intersected with the traditional level of statistical favoring acupuncture, and more RCTs will required in the future studies.

Conclusion

Acupuncture has beneficial effect on pain relief and improves function activities, and this treatment can be recommended as a beneficial alternative therapy in patients with KOA, particularly for chronic patients and those currently undergoing long-term pain and help them increasing quality of life. But it should be further verified through more RCTs in function. Available studies suggested that acupuncture was superior to sham acupuncture in reduce pain and function as verified by TSA.

Molecular characterization of matrix metalloproteinase gene family across primates

Deregulation of matrix metalloproteinases (MMPs) contributes considerably to cancers, psychiatric disorders, macular degeneration and bone diseases. The use of humans in the development of MMPs as prognostic biomarkers and therapeutic targets is complicated by many factors, while primate models can be useful alternatives for this purpose. Here, we performed genome-enabled identification of putative MMPs across primate species, and comprehensively investigated the genes. Phylogenetic topology of the MMP family showed each type formulates a distinct clade, and was further clustered to classes, largely agreeing with classification based on biochemical properties and domain organization. Across primates, the excess of candidate sites of positive selection was detected for MMP-19, in addition to 1-3 sites in MMP-8, MMP-10 and MMP-26. MMP-26 showed Ka/Ks value above 1 between human and chimpanzee copies. We observed two copies of MMP-19 in the old-world monkey genomes, suggesting gene duplication at the early stage of or prior to the emergence of the lineage. Furin-activatable MMPs demonstrate the most variable properties regarding Domain organization and gene structure. During human aging, MMP-11 showed gradually decreased expression in testis, so as MMP-2, MMP-14, MMP15 and MMP-28 in ovary, while MMP-7 and MMP-21 showed elevated expression, implying their distinct roles in different reproductive organs. Co-expression clusters were formed among human MMPs both within and across classes, and expression correlation was observed in MMP genes across primates. Our results illuminate the utilization of MMPs for the discovery of prognostic biomarkers and therapeutic targets for aging-related diseases and carry new messages on MMP classification.

New insights into the role of Matrix Metalloproteinase 3 ( MMP3 ) in bone

The Matrix Metalloproteinases are important regulators of bone metabolism and can influence bone mass and bone remodeling. We investigate the role of Matrix Metalloproteinase 3 (MMP3) on bone in mice, by using Mmp3 knockout (Mmp3 KO) in the context of estrogen deficiency, and in human, by analyzing the association of promoter polymorphism with bone mineral density in postmenopausal women and with MMP3 expression. We presented evidence in this paper that Mmp3 KO significantly increases trabecular bone mass and trabecular number and does not affect cortical bone thickness. We also found that Mmp3 KO protects from the deleterious effects of ovariectomy on bone mineral density in mice by preventing deterioration of bone microarchitecture. The effect of Mmp3 KO does not involve bone formation parameters but instead acts by inhibition of bone resorption, leading to a reduced bone loss associated to ovariectomy. By studying a human cohort, we found that a polymorphism located in the promoter of the human MMP3 gene is associated with bone mineral density in postmenopausal women and found that MMP3 rs632478 promoter variants are associated with change in promoter activity in transfection experiments. In conclusion MMP3, although weakly expressed in bone cells, could be one of the important regulators of sex hormone action in bone and whose activity could be targeted for therapeutic applications such as in Osteoporosis.

Supramolecular Peptide Nanofiber Hydrogels for Bone Tissue Engineering: From Multihierarchical Fabrications to Comprehensive Applications

Bone tissue engineering is becoming an ideal strategy to replace autologous bone grafts for surgical bone repair, but the multihierarchical complexity of natural bone is still difficult to emulate due to the lack of suitable biomaterials. Supramolecular peptide nanofiber hydrogels (SPNHs) are emerging biomaterials because of their inherent biocompatibility, satisfied biodegradability, high purity, facile functionalization, and tunable mechanical properties. This review initially focuses on the multihierarchical fabrications by SPNHs to emulate natural bony extracellular matrix. Structurally, supramolecular peptides based on distinctive building blocks can assemble into nanofiber hydrogels, which can be used as nanomorphology-mimetic scaffolds for tissue engineering. Biochemically, bioactive motifs and bioactive factors can be covalently tethered or physically absorbed to SPNHs to endow various functions depending on physiological and pharmacological requirements. Mechanically, four strategies are summarized to optimize the biophysical microenvironment of SPNHs for bone regeneration. Furthermore, comprehensive applications about SPNHs for bone tissue engineering are reviewed. The biomaterials can be directly used in the form of injectable hydrogels or composite nanoscaffolds, or they can be used to construct engineered bone grafts by bioprinting or bioreactors. Finally, continuing challenges and outlook are discussed.

Engineering hypertrophic cartilage grafts from lipoaspirate for critical‐sized calvarial bone defect reconstruction: An adipose tissue‐based developmental engineering approach

Developmental engineering of living implants from different cell sources capable of stimulating bone regeneration by recapitulating endochondral ossification (ECO) is a promising strategy for large bone defect reconstruction. However, the clinical translation of these cell‐based approaches is hampered by complex manufacturing procedures, poor cell differentiation potential, and limited predictive in vivo performance. We developed an adipose tissue‐based developmental engineering approach to overcome these hurdles using hypertrophic cartilaginous (HyC) constructs engineered from lipoaspirate to repair large bone defects. The engineered HyC constructs were implanted into 4‐mm calvarial defects in nude rats and compared with decellularized bone matrix (DBM) grafts. The DBM grafts induced neo‐bone formation via the recruitment of host cells, while the HyC pellets supported bone regeneration via ECO, as evidenced by the presence of remaining cartilage analog and human NuMA‐positive cells within the newly formed bone. However, the HyC pellets clearly showed superior regenerative capacity compared with that of the DBM grafts, yielding more new bone formation, higher blood vessel density, and better integration with adjacent native bone. We speculate that this effect arises from vascular endothelial growth factor and bone morphogenetic protein‐2 secretion and mineral deposition in the HyC pellets before implantation, promoting increased vascularization and bone formation upon implantation. The results of this study demonstrate that adipose‐derived HyC constructs can effectively heal large bone defects and present a translatable therapeutic option for bone defect repair.

Transcriptome Profiling of Osteoblasts in a Medaka (Oryzias latipes) Osteoporosis Model Identifies Mmp13b as Crucial for Osteoclast Activation

Matrix metalloproteases (MMPs) play crucial roles in extracellular matrix (ECM) modulation during osteoclast-driven bone remodeling. In the present study, we used transcriptome profiling of bone cells in a medaka model for osteoporosis and bone regeneration to identify factors critical for bone remodeling and homeostasis. This identified mmp13b, which was strongly expressed in osteoblast progenitors and upregulated under osteoporotic conditions and during regeneration of bony fin rays. To characterize the role of mmp13b in bone remodeling, we generated medaka mmp13b mutants by CRISPR/Cas9. We found that mmp13b mutants form normal numbers of osteoblasts and osteoclasts. However, osteoclast activity was severely impaired under osteoporotic conditions. In mmp13b mutants and embryos treated with the MMP13 inhibitor CL-82198, unmineralized collagens and mineralized bone matrix failed to be degraded. In addition, the dynamic migratory behavior of activated osteoclasts was severely affected in mmp13b mutants. Expression analysis showed that maturation genes were downregulated in mmp13b deficient osteoclasts suggesting that they remain in an immature and non-activated state. We also found that fin regeneration was delayed in mmp13b mutants with a concomitant alteration of the ECM and reduced numbers of osteoblast progenitors in regenerating joint regions. Together, our findings suggest that osteoblast-derived Mmp13b alters the bone ECM to allow the maturation and activation of osteoclasts during bone remodeling in a paracrine manner. Mmp13b-induced ECM alterations are also required to facilitate osteoblast progenitor recruitment and full regeneration of bony fin rays.

The antinociceptive effect of garlic, garlic preparations, and derivative compounds

The antinociceptive effects of garlic have shown promise in treating different chronic diseases in humans, such as knee osteoarthritis, rheumatoid arthritis, and peripheral arterial occlusive disease stage II. The most common garlic products are garlic powder (dried garlic), steam distilled garlic oils, garlic oil macerate, and aged garlic extract. These commercial products contain organosulfur compounds (OSC) that have been extensively evaluated in preclinical models and some clinical assays to treat different diseases against pain. In this review, we describe the importance of some bioactive compounds found in garlic and its role in treating pain. A systematic search of the literature in Dimensions, PubMed, Scopus, Web of Science was performed. Terms and preselected keywords relating to garlic, its derivates and organusulfur compunds in pain, were used to perform a systematic literature search. Two independent reviewers screened papers for inclusion and assessed the methodological quality. The antinociceptive activity of garlic and its OSC is related to its antioxidant and anti-inflammatory properties, which may be explained by the ability to block the synthesis of PGs, pro-inflammatory cytokines and interferon-γ, by the reduction COX- 2 activity and by increases the levels of anti-inflammatory cytokines. Besides, garlic extract is an activator of TRPA1 and TRPV1, where the principal responsible for this activation are OSC. The relationship between these pathways allows a better understanding how garlic and its derivates could be carrying out its pharmacological action over the management of acute and chronic pain and provide a base by further investigations.

NMR Metabolomics Assessment of Osteogenic Differentiation of Adipose-Tissue-Derived Mesenchymal Stem Cells

This Article presents, for the first time to our knowledge, an untargeted nuclear magnetic resonance (NMR) metabolomic characterization of the polar intracellular metabolic adaptations of human adipose-derived mesenchymal stem cells during osteogenic differentiation. The use of mesenchymal stem cells (MSCs) for bone regeneration is a promising alternative to conventional bone grafts, and untargeted metabolomics may unveil novel metabolic information on the osteogenic differentiation of MSCs, allowing their behavior to be understood and monitored/guided toward effective therapies. Our results unveiled statistically relevant changes in the levels of just over 30 identified metabolites, illustrating a highly dynamic process with significant variations throughout the whole 21-day period of osteogenic differentiation, mainly involving amino acid metabolism and protein synthesis; energy metabolism and the roles of glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation; cell membrane metabolism; nucleotide metabolism (including the specific involvement of O-glycosylation intermediates and NAD⁺); and metabolic players in protective antioxidative mechanisms (such as glutathione and specific amino acids). Different metabolic stages are proposed and are supported by putative biochemical explanations for the metabolite changes observed. This work lays the groundwork for the use of untargeted NMR metabolomics to find potential metabolic markers of osteogenic differentiation efficacy.

Mineralized Peyronie's plaque has a phenotypic resemblance to bone

Mineralized Peyronie's plaque (MPP) impairs penile function. The association, colocalization, and dynamic interplay between organic and inorganic constituents can provide insights into biomineralization of Peyronie's plaque. Human MPPs (n = 11) were surgically excised, and the organic and inorganic constituents were spatially mapped using multiple high-resolution imaging techniques. Multiscale image analyses resulted in spatial colocalization of elements within a highly porous material with heterogenous composition, lamellae, and osteocytic lacuna-like features with a morphological resemblance to bone. The lower (520 ± 179 mg/cc) and higher (1024 ± 155 mg/cc) mineral density regions were associated with higher (11%) and lower (7%) porosities in MPP. Energy dispersive X-ray and micro-X-ray fluorescent spectroscopic maps in the higher mineral density regions of MPP revealed higher counts of calcium (Ca) and phosphorus (P), and a Ca/P ratio of 1.48 ± 0.06 similar to bone. More importantly, higher counts of zinc (Zn) were localized at the interface between softer (more organic to inorganic ratio) and harder (less organic to inorganic ratio) tissue regions of MPP and adjacent softer matrix, indicating the involvement of Zn-related proteins and/or pathways in the formation of MPP. In particular, dentin matrix protein-1 (DMP-1) was colocalized in a matrix rich in proteoglycans and collagen that contained osteocytic lacuna-like features. This combined materials science and biochemical with correlative microspectroscopic approach provided insights into the plausible cellular and biochemical pathways that incite mineralization of an existing fibrous Peyronie's plaque. STATEMENT OF SIGNIFICANCE: Aberrant human penile mineralization is known as mineralized Peyronie's plaque (MPP) and often results in a loss of form and function. This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing calcium, phosphorus, and trace metal zinc with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high resolution correlative microspectroscopy techniques. Spatial maps provided insights into cellular and biochemical pathways that incite mineralization of fibrous Peyronie's plaque in humans.

Effect of single-dose locally applied lactoferrin on autograft healing in peri-implant bone in rat models

Immediate dental implant installation into fresh extraction sockets has become a common surgical technique and yields successful clinical results. In addition, complete contact may not be possible with this procedure cause of defects between the bone wall and the implant surface. Therefore, different graft materials have been used in the literature to increase the peri‑implant bone volume. The aim of the present study was to evaluate the effect of single-dose and locally applied lactoferrin on autograft healing in peri‑implant area and bone implant contact value. Twenty-four Sprague-Dawley rats were included in this study. Firstly, a trephine drill was used for creating a cylindrical bony defects (6.5 mm in diameter and 3 mm in depth) under sterile saline irrigation in the lateral side of the femur. Subsequently, implant beds -2.5 mm diameter and 6 mm depth - were prepared in the middle of each defect with special implant drills. All of the implants were installed and primary stability was achieved. Rats were randomly divided into 3 groups (n = 8 each): Group-1 had empty defects, Group-2 had defects filled with autograft, and Group-3 had defects filled with autograft and lactoferrin solution (100 μg/ml) combination. All of the rats were sacrificed at postoperative 4th week and samples were analyzed with micro-computed tomography, histomorphometry and immunohistochemistry respectively. It was found that Group 3 had the least area of fibrous tissue (6.75±0.83mm²) according to the other 2 groups (p<0.001). On the other hand, Group 3 had the highest osteoblast number (25.50±3.29), osteoclast number (21.25±1.03), newly formed bone area (20.50±1.30 mm²), total healing area (22.62±0.93 mm²), defect closure rate (80.37±1.40%), bone implant contact value (23.2%±0.6%), and percentage bone volume (18.2%±0.3%) (p<0.001). Matrix metalloproteinase-3 expression was found to be highest in Group 3 by immunohistochemistry analysis. In this study it was observed that the results of the different analysis techniques supported each other. According to these findings it can be stated that a single-dose and locally applied lactoferrin solution plays an important role in the autograft healing in peri‑implant area and increasing bone implant contact value. These findings will shed light on further clinical studies of implant osseointegration.