CD39 Produced from Human GMSCs Regulates the Balance of Osteoclasts and Osteoblasts through the Wnt/β-Catenin Pathway in Osteoporosis

Current Perspectives of Protein in Bone Tissue Engineering: Bone Structure, Ideal Scaffolds, Fabrication Techniques, Applications, Scopes, and Future Advances

In view of their exceptional approach, excellent inherent biocompatibility and biodegradability properties, and interaction with the local extracellular matrix, protein-based polymers have received attention in bone tissue engineering, which is a multidisciplinary field that repairs and regenerates fractured bones. Bone is a multihierarchical complex structure, and it performs several essential biofunctions, including maintaining mineral balance and structural support and protecting soft organs. Protein-based polymers have gained interest in developing ideal scaffolds as emerging biomaterials for bone fractured healing and regeneration, and it is challenging to design ideal bone substitutes as perfect biomaterials. Several protein-based polymers, including collagen, keratin, gelatin, serum albumin, etc., are potential materials due to their inherent cytocompatibility, controlled biodegradability, high biofunctionalization, and tunable mechanical characteristics. While numerous studies have indicated the encouraging possibilities of proteins in BTE, there are still major challenges concerning their biodegradability, stability in physiological conditions, and continuous release of growth factors and bioactive molecules. Robust scaffolds derived from proteins can be used to replace broken or diseased bone with a biocompatible substitute; proteins, being biopolymers, provide excellent scaffolds for bone tissue engineering. Herein, recent developments in protein polymers for cutting-edge bone tissue engineering are addressed in this review within 3-5 years, with a focus on the significant challenges and future perspectives. The first section discusses the structural fundamentals of bone anatomy and ideal scaffolds, and the second section describes the fabrication techniques of scaffolds. The third section highlights the importance of proteins and their applications in BTE. Hence, the recent development of protein polymers for state-of-the-art bone tissue engineering has been discussed, highlighting the significant challenges and future perspectives.

An exploration of the causal relationship between 731 immunophenotypes and osteoporosis: a bidirectional Mendelian randomized study

Background

There are complex interactions between osteoporosis and the immune system, and it has become possible to explore their causal relationship based on Mendelian randomization methods.

Methods

Utilizing openly accessible genetic data and employing Mendelian randomization analysis, we investigated the potential causal connection between 731 immune cell traits and the risk of developing osteoporosis.

Results

Ten immune cell phenotypes were osteoporosis protective factors and three immune cell phenotypes were osteoporosis risk factors. Specifically, the odds ratio (OR) of IgD+ CD24+ %B cell (B cell panel) risk on Osteoporosis was estimated to be 0.9986 (95% CI = 0.9978~0.9996, P<0.01). The OR of CD24+ CD27+ %B cell (B cell panel) risk on Osteoporosis was estimated to be 0.9991 (95% CI = 0.9984~0.9998, P = 0.021). The OR of CD33- HLA DR+AC (Myeloid cell panel) risk on Osteoporosis was estimated to be 0.9996 (95% CI = 0.9993~0.9999, P = 0.038). The OR of EM CD8br %CD8br (Maturation stages of T cell panel) risk on Osteoporosis was estimated to be 1.0004 (95% CI = 1.0000~1.0008, P = 0.045). The OR of CD25 on IgD+ (B cell panel) risk on Osteoporosis was estimated to be 0.9995 (95% CI = 0.9991~0.9999, P = 0.024). The OR of CD25 on CD39+ activated Treg+ (Treg panel) risk on Osteoporosis was estimated to be 1.001 (95% CI = 1.0001~1.0019, P = 0.038). The OR of CCR2 on CD62L+ myeloid DC (cDC panel) risk on Osteoporosis was estimated to be 0.9992 (95% CI = 0.9984~0.9999, P = 0.048). The OR of CCR2 on CD62L+ plasmacytoid DC (cDC panel) risk on Osteoporosis was estimated to be 0.9993 (95% CI = 0.9987~0.9999, P = 0.035). The OR of CD45 on CD33dim HLA DR+ CD11b- (Myeloid cell panel) risk on Osteoporosis was estimated to be 0.9988 (95% CI = 0.9977~0.9998, P = 0.031). The OR of CD45 on Mo MDSC (Myeloid cell panel) risk on Osteoporosis was estimated to be 0.9992 (95% CI = 0.9985~0.9998, P = 0.017). The OR of SSC-A on B cell (TBNK panel) risk on Osteoporosis was estimated to be 0.9986 (95% CI = 0.9972~0.9999, P = 0.042). The OR of CD11c on CD62L+ myeloid DC (cDC panel) risk on Osteoporosis was estimated to be 0.9987 (95% CI = 0.9978~0.9996, P<0.01). The OR of HLA DR on DC (cDC panel) risk on Osteoporosis was estimated to be 1.0007 (95% CI = 1.0002~1.0011, P<0.01). No causal effect of osteoporosis on immune cells was observed.

Conclusions

Our study identified 13 unreported immune phenotypes that are causally related to osteoporosis, providing a theoretical basis for the bone immunology doctrine.

Osteoporosis: Emerging targets on the classical signaling pathways of bone formation

Osteoporosis is a multifaceted skeletal disorder characterized by reduced bone mass and structural deterioration, posing a significant public health challenge, particularly in the elderly population. Treatment strategies for osteoporosis primarily focus on inhibiting bone resorption and promoting bone formation. However, the effectiveness and limitations of current therapeutic approaches underscore the need for innovative methods. This review explores emerging molecular targets within crucial signaling pathways, including wingless/integrated (WNT), bone morphogenetic protein (BMP), hedgehog (HH), and Notch signaling pathway, to understand their roles in osteogenesis regulation. The identification of crosstalk targets between these pathways further enhances our comprehension of the intricate bone metabolism cycle. In summary, unraveling the molecular complexity of osteoporosis provides insights into potential therapeutic targets beyond conventional methods, offering a promising avenue for the development of new anabolic drugs.

Advancing skeletal health and disease research with single-cell RNA sequencing

Orthopedic conditions have emerged as global health concerns, impacting approximately 1.7 billion individuals worldwide. However, the limited understanding of the underlying pathological processes at the cellular and molecular level has hindered the development of comprehensive treatment options for these disorders. The advent of single-cell RNA sequencing (scRNA-seq) technology has revolutionized biomedical research by enabling detailed examination of cellular and molecular diversity. Nevertheless, investigating mechanisms at the single-cell level in highly mineralized skeletal tissue poses technical challenges. In this comprehensive review, we present a streamlined approach to obtaining high-quality single cells from skeletal tissue and provide an overview of existing scRNA-seq technologies employed in skeletal studies along with practical bioinformatic analysis pipelines. By utilizing these methodologies, crucial insights into the developmental dynamics, maintenance of homeostasis, and pathological processes involved in spine, joint, bone, muscle, and tendon disorders have been uncovered. Specifically focusing on the joint diseases of degenerative disc disease, osteoarthritis, and rheumatoid arthritis using scRNA-seq has provided novel insights and a more nuanced comprehension. These findings have paved the way for discovering novel therapeutic targets that offer potential benefits to patients suffering from diverse skeletal disorders.

Gingival-derived mesenchymal stem cells alleviate allergic asthma inflammation via HGF in animal models

Allergic asthma is a chronic non-communicable disease characterized by lung tissue inflammation. Current treatments can alleviate the clinical symptoms to some extent, but there is still no cure. Recently, the transplantation of mesenchymal stem cells (MSCs) has emerged as a potential approach for treating allergic asthma. Gingival-derived mesenchymal stem cells (GMSCs), a type of MSC recently studied, have shown significant therapeutic effects in various experimental models of autoimmune diseases. However, their application in allergic diseases has yet to be fully elucidated. In this study, using an OVA-induced allergic asthma model, we demonstrated that GMSCs decrease CD11b+CD11c+ proinflammatory dendritic cells (DCs), reduce Th2 cells differentiation, and thus effectively diminish eosinophils infiltration. We also identified that the core functional factor, hepatocyte growth factor (HGF) secreted by GMSCs, mediated its effects in relieving airway inflammation. Taken together, our findings indicate GMSCs as a potential therapy for allergic asthma and other related diseases.

Unveiling heterogeneity in MSCs: exploring marker-based strategies for defining MSC subpopulations

Mesenchymal stem/stromal cells (MSCs) represent a heterogeneous cell population distributed throughout various tissues, demonstrating remarkable adaptability to microenvironmental cues and holding immense promise for disease treatment. However, the inherent diversity within MSCs often leads to variability in therapeutic outcomes, posing challenges for clinical applications. To address this heterogeneity, purification of MSC subpopulations through marker-based isolation has emerged as a promising approach to ensure consistent therapeutic efficacy. In this review, we discussed the reported markers of MSCs, encompassing those developed through candidate marker strategies and high-throughput approaches, with the aim of explore viable strategies for addressing the heterogeneity of MSCs and illuminate prospective research directions in this field.

miRNA-148a-containing GMSC-derived EVs modulate Treg/Th17 balance via IKKB/NF-κB pathway and treat a rheumatoid arthritis model

Mesenchymal stem cells (MSCs) have demonstrated potent immunomodulatory properties that have shown promise in the treatment of autoimmune diseases, including rheumatoid arthritis (RA). However, the inherent heterogeneity of MSCs triggered conflicting therapeutic outcomes, raising safety concerns and limiting their clinical application. This study aimed to investigate the potential of extracellular vesicles derived from human gingival mesenchymal stem cells (GMSC-EVs) as a therapeutic strategy for RA. Through in vivo experiments using an experimental RA model, our results demonstrate that GMSC-EVs selectively homed to inflamed joints and recovered Treg and Th17 cell balance, resulting in the reduction of arthritis progression. Our investigations also uncovered miR-148a-3p as a critical contributor to the Treg/Th17 balance modulation via IKKB/NF-κB signaling orchestrated by GMSC-EVs, which was subsequently validated in a model of human xenograft versus host disease (xGvHD). Furthermore, we successfully developed a humanized animal model by utilizing synovial fibroblasts obtained from patients with RA (RASFs). We found that GMSC-EVs impeded the invasiveness of RASFs and minimized cartilage destruction, indicating their potential therapeutic efficacy in the context of patients with RA. Overall, the unique characteristics - including reduced immunogenicity, simplified administration, and inherent ability to target inflamed tissues - position GMSC-EVs as a viable alternative for RA and other autoimmune diseases.

Lactobacillus reuteri for chronic periodontitis: focus on underlying mechanisms and future perspectives

Chronic periodontitis is a common oral disorder caused by pathogenic bacteria. Despite the wide use of antibiotics as the conventional adjunctive treatment, the challenges of increased antibiotic resistance and limited therapeutic effect receive considerable attention and the developments of alternative treatments gain increasing consideration. Growing evidence showed that Lactobacillus reuteri (LR) may represent a promising alternative adjunct for chronic periodontitis. It can attenuate inflammation and reduce tissue disruption. LR-assisted treatment has been shown to be effective and relatively safe in multiple clinical trials, and accumulating evidence suggests its significant biological roles. In the current review, we focus on capturing the underlying mechanisms of LR involved in chronic periodontitis, thereby representing a scientific foundation for LR-assisted therapy. Furthermore, we point out the challenges and future directions for further clinical trials to improve the clinical applicability for LR.

Infusion of GMSCs relieves autoimmune arthritis by suppressing the externalization of neutrophil extracellular traps via PGE2-PKA-ERK axis

INTRODUCTION

Rheumatoid arthritis (RA) is a systemic autoimmune disease with limited treatment success, characterized by chronic inflammation and progressive cartilage and bone destruction. Accumulating evidence has shown that neutrophil extracellular traps (NETs) released by activated neutrophils are important for initiating and perpetuating synovial inflammation and thereby could be a promising therapeutic target for RA. K/B × N serum transfer-induced arthritis (STIA) is a rapidly developed joint inflammatory model that somehow mimics the inflammatory response in patients with RA. Human gingival-derived mesenchymal stem cells (GMSCs) have been previously shown to possess immunosuppressive effects in arthritis and humanized animal models. However, it is unknown whether GMSCs can manage neutrophils in autoimmune arthritis.

OBJECTIVES

To evaluate whether infusion of GMSCs can alleviate RA by regulating neutrophils and NETs formation. If this is so, we will explore the underlying mechanism(s) in an animal model of inflammatory arthritis.

METHODS

The effects of GMSCs on RA were assessed by comparing the symptoms of the K/B × N serum transfer-induced arthritis (STIA) model administered either with GMSCs or with control cells. Phenotypes examined included clinical scores, rear ankle thickness, paw swelling, inflammation, synovial cell proliferation, and immune cell frequency. The regulation of GMSCs on NETs was examined through immunofluorescence and immunoblotting in GMSCs-infused STIA mice and in an in vitro co-culture system of neutrophils with GMSCs. The molecular mechanism(s) by which GMSCs regulate NETs was explored both in vitro and in vivo by silencing experiments.

RESULTS

We found in this study that adoptive transfer of GMSCs into STIA mice significantly ameliorated experimental arthritis and reduced neutrophil infiltration and NET formation. In vitro studies also showed that GMSCs inhibited the generation of NETs in neutrophils. Subsequent investigations revealed that GMSCs secreted prostaglandin E2 (PGE2) to activate protein kinase A (PKA), which ultimately inhibited the downstream extracellular signal-regulated kinase (ERK) pathway that is essential for NET formation.

CONCLUSION

Our results demonstrate that infusion of GMSCs can ameliorate inflammatory arthritis mainly by suppressing NET formation via the PGE2-PKA-ERK signaling pathway. These findings further support the notion that the manipulation of GMSCs is a promising stem cell-based therapy for patients with RA and other autoimmune and inflammatory diseases.

Compounding engineered mesenchymal stem cell-derived exosomes: A potential rescue strategy for retinal degeneration

The prevalence of retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, has been increasing globally and is linked to the aging population and improved life expectancy. These diseases are characterized by chronic, progressive neuronal damage or depletion of the photoreceptor cells in the retina, and limited effective treatment options are currently available. Mesenchymal stem cell-derived exosomes (MSC-EXOs) containing cytokines, growth factors, lipids, mRNA, and miRNA, which act as mediators of intercellular communication transferring bioactive molecules to recipient cells, offer an appealing, non-cellular nanotherapeutic approach for retinal degenerative diseases. However, treatment specificity is compromised due to their high heterogeneity in size, content, functional effects, and parental cellular source. To improve this, engineered MSC-EXOs with increased drug-loading capacity, targeting ability, and resistance to bodily degradation and elimination have been developed. This review summarizes the recent advances in miRNAs of MSC-EXOs as a treatment for retinal degeneration, discussing the strategies and methods for engineering therapeutic MSC-EXOs. Notably, to address the single functional role of engineered MSC-EXOs, we propose a novel concept called "Compound Engineered MSC-EXOs (Co-E-MSC-EXOs)" along with its derived potential therapeutic approaches. The advantages and challenges of employing Co-E-MSC-EXOs for retinal degeneration in clinical applications, as well as the strategies and issues related to them, are also highlighted.

Proteome-wide profiling reveals dysregulated molecular features and accelerated aging in osteoporosis: A 9.8-year prospective study

The role of circulatory proteomics in osteoporosis is unclear. Proteome-wide profiling holds the potential to offer mechanistic insights into osteoporosis. Serum proteome with 413 proteins was profiled by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at baseline, and the 2nd, and 3rd follow-ups (7704 person-tests) in the prospective Chinese cohorts with 9.8 follow-up years: discovery cohort (n = 1785) and internal validation cohort (n = 1630). Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DXA) at follow-ups 1 through 3 at lumbar spine (LS) and femoral neck (FN). We used the Light Gradient Boosting Machine (LightGBM) to identify the osteoporosis (OP)-related proteomic features. The relationships between serum proteins and BMD in the two cohorts were estimated by linear mixed-effects model (LMM). Meta-analysis was then performed to explore the combined associations. We identified 53 proteins associated with osteoporosis using LightGBM, and a meta-analysis showed that 22 of these proteins illuminated a significant correlation with BMD (p < 0.05). The most common proteins among them were PHLD, SAMP, PEDF, HPTR, APOA1, SHBG, CO6, A2MG, CBPN, RAIN APOD, and THBG. The identified proteins were used to generate the biological age (BA) of bone. Each 1 SD-year increase in KDM-Proage was associated with higher risk of LS-OP (hazard ratio [HR], 1.25; 95% CI, 1.14-1.36, p = 4.96 × 10-06 ), and FN-OP (HR, 1.13; 95% CI, 1.02-1.23, p = 9.71 × 10-03 ). The findings uncovered that the apolipoproteins, zymoproteins, complements, and binding proteins presented new mechanistic insights into osteoporosis. Serum proteomics could be a crucial indicator for evaluating bone aging.

Gingival mesenchymal stem cell therapy, immune cells, and immunoinflammatory application

MSC-based therapeutic strategies have proven to be incredibly effective. Robust self-renewal, multilineage differentiation, and potential for tissue regeneration and disease treatments are all features of MSCs isolated from oral tissue. Human exfoliated deciduous teeth, dental follicles, dental pulp, apical papilla SCs, and alveolar bone are the primary sources of oral MSC production. The early immunoinflammatory response is the first stage of the healing process. Oral MSCs can interact with various cells, such as immune cells, revealing potential immunomodulatory regulators. They also have strong differentiation and regeneration potential. Therefore, a ground-breaking strategy would be to research novel immunomodulatory approaches for treating disease and tissue regeneration that depend on the immunomodulatory activities of oral MSCs during tissue regeneration.

Carnosine, Zinc and Copper: A Menage a Trois in Bone and Cartilage Protection

Dysregulated metal homeostasis is associated with many pathological conditions, including arthritic diseases. Osteoarthritis and rheumatoid arthritis are the two most prevalent disorders that damage the joints and lead to cartilage and bone destruction. Recent studies show that the levels of zinc (Zn) and copper (Cu) are generally altered in the serum of arthritis patients. Therefore, metal dyshomeostasis may reflect the contribution of these trace elements to the disease's pathogenesis and manifestations, suggesting their potential for prognosis and treatment. Carnosine (Car) also emerged as a biomarker in arthritis and exerts protective and osteogenic effects in arthritic joints. Notably, its zinc(II) complex, polaprezinc, has been recently proposed as a drug-repurposing candidate for bone fracture healing. On these bases, this review article aims to provide an overview of the beneficial roles of Cu and Zn in bone and cartilage health and their potential application in tissue engineering. The effects of Car and polaprezinc in promoting cartilage and bone regeneration are also discussed. We hypothesize that polaprezinc could exchange Zn for Cu, present in the culture media, due to its higher sequestering ability towards Cu. However, future studies should unveil the potential contribution of Cu in the beneficial effects of polaprezinc.

Amelioration of exosome and mesenchymal stem cells in rats infected with diabetic nephropathy by attenuating early markers and aquaporin-1 expression

Diabetic nephropathy (DN) is a prevalent diabetic microvascular condition. It is the leading cause of kidney disease in the advanced stages. There is no currently effective treatment available. This research aimed to investigate the curative potentials of exosomes isolated from mesenchymal stem cells affecting DN. This study was performed on 70 male adult albino rats. Adult rats were randomized into seven groups: Group I: Negative control group, Group II: DN group, Group III: Balanites treated group, Group IV: MSCs treated group, Group V: Exosome treated group, Group VI: Balanites + MSCs treated group and Group VII: Balanites + exosome treated group. Following the trial period, blood and renal tissues were subjected to biochemical, gene expression analyses, and histopathological examinations. Results showed that MDA was substantially increased, whereas TAC was significantly decreased in the kidney in the DN group compared to normal health rats. Undesired elevated values of MDA levels and a decrease in TAC were substantially ameliorated in groups co-administered Balanites aegyptiacae with MSCs or exosomes compared to the DN group. A substantial elevation in TNF-α and substantially diminished concentration of IGF-1 were noticed in DN rats compared to normal health rats. Compared to the DN group, the co-administration of Balanites aegyptiacae with MSCs or exosomes substantially improved the undesirable elevated values of TNF-α and IGF-1. Furthermore, in the DN group, the mRNA expression of Vanin-1, Nephrin, and collagen IV was significantly higher than in normal healthy rats. Compared with DN rats, Vanin-1, Nephrin, and collagen IV Upregulation were substantially reduced in groups co-administered Balanites aegyptiacae with MSCs or exosomes. In DN rats, AQP1 expression was significantly lower than in normal healthy rats. Furthermore, the groups co-administered Balanites aegyptiacae with MSCs or exosomes demonstrated a substantial increase in AQP1 mRNA expression compared to DN rats.

Global biomarkers of oxidative stress and fractures: a matched case-control study

Background

Evidence for a relationship between oxidative stress and osteoporotic fractures in humans is limited. Fluorescent oxidation products (FlOPs, excitation/emission wavelengths 320/420nm denoted FlOP_320; 360/420nm [FlOP_360]; and 400/475nm [FlOP_400]) are global biomarkers of oxidative stress, and reflect oxidative damage to proteins, phospholipids, and nucleic acids. We investigated the association between FlOPs and a recent osteoporotic fracture.

Methods

We conducted a case-control study in a Chinese population aged 50 years or older. A recent osteoporotic fracture in the cases was confirmed by x-ray. Cases were matched with community-based non-fracture controls (1:2 ratio) for age (± 4 years) and sex. In addition, we conducted a sensitivity unmatched case-control study which included all fracture cases and all eligible non-fracture controls prior to matching. Plasma FlOPs were measured with a fluorescent microplate reader. We used unconditional logistic regression to analyze the association between FlOPs (per 1-SD increase in logarithmic scale) and fracture; odds ratios (OR) and 95% confidence intervals (95% CI) were reported.

Results

Forty-four cases and 88 matched controls (mean age: 68.2 years) were included. After covariate adjustment (i.e., body mass index, physical activity, and smoking), higher FlOP_360 (OR = 1.85; 95% CI = 1.03 - 3.34) and FlOP_400 (OR = 13.29; 95% CI = 3.48 - 50.69) levels, but not FlOP_320 (OR = 0.56; 95% CI = 0.27 - 1.15), were associated with increased fracture risk. Subgroup analyses by fracture site and unmatched case-control study found comparable associations of FlOP_360 and FlOP_400 with hip and non-hip fractures.

Conclusions

Higher FlOP_360 and FlOP_400 levels were associated with increased risk of fracture, and this association was comparable for hip and non-hip fractures. Prospective studies are warranted to confirm this finding.

Could hypoxia rehabilitate the osteochondral diseased interface? Lessons from the interplay of hypoxia and purinergic signals elsewhere

The osteochondral unit comprises the articular cartilage (90%), subchondral bone (5%) and calcified cartilage (5%). All cells present at the osteochondral unit that is ultimately responsible for matrix production and osteochondral homeostasis, such as chondrocytes, osteoblasts, osteoclasts and osteocytes, can release adenine and/or uracil nucleotides to the local microenvironment. Nucleotides are released by these cells either constitutively or upon plasma membrane damage, mechanical stress or hypoxia conditions. Once in the extracellular space, endogenously released nucleotides can activate membrane-bound purinoceptors. Activation of these receptors is fine-tuning regulated by nucleotides' breakdown by enzymes of the ecto-nucleotidase cascade. Depending on the pathophysiological conditions, both the avascular cartilage and the subchondral bone subsist to significant changes in oxygen tension, which has a tremendous impact on tissue homeostasis. Cell stress due to hypoxic conditions directly influences the expression and activity of several purinergic signalling players, namely nucleotide release channels (e.g. Cx43), NTPDase enzymes and purinoceptors. This review gathers experimental evidence concerning the interplay between hypoxia and the purinergic signalling cascade contributing to osteochondral unit homeostasis. Reporting deviations to this relationship resulting from pathological alterations of articular joints may ultimately unravel novel therapeutic targets for osteochondral rehabilitation. At this point, one can only hypothesize how hypoxia mimetic conditions can be beneficial to the ex vivo expansion and differentiation of osteo- and chondro-progenitors for auto-transplantation and tissue regenerative purposes.

Comparison of Biological Properties and Clinical Application of Mesenchymal Stem Cells from the Mesoderm and Ectoderm

Since the discovery of mesenchymal stem cells (MSCs) in the 1970s, they have been widely used in the treatment of a variety of diseases because of their wide sources, strong differentiation potential, rapid expansion in vitro, low immunogenicity, and so on. At present, most of the related research is on mesoderm-derived MSCs (M-MSCs) such as bone marrow MSCs and adipose-derived MSCs. As a type of MSC, ectoderm-derived MSCs (E-MSCs) have a stronger potential for self-renewal, multidirectional differentiation, and immunomodulation and have more advantages than M-MSCs in some specific conditions. This paper analyzes the relevant research development of E-MSCs compared with that of M-MSCs; summarizes the extraction, discrimination and culture, biological characteristics, and clinical application of E-MSCs; and discusses the application prospects of E-MSCs. This summary provides a theoretical basis for the better application of MSCs from both ectoderm and mesoderm in the future.

Effects of phthalates on human chorionic trophoblast cells and mouse embryonic development

Phthalate exposure is associated with reproductive health, but the mechanism is unclear. This study used human chorionic trophoblast epithelial cells (HTR8/Svneo cells) and mouse embryos as objects aims to explore the effects of phthalate plasticizers on germ cells and fertility and the possible signalling pathways. In the present study, high concentrations of MEHP for 24 h significantly inhibited the proliferation and viability of HTR8/SVneo cells. Compared with the negative control (NC) group, the MEHP medium and high concentration groups promoted the apoptosis of HTR8/SVneo cells and inhibited the cell cycle, HTR8/SVneo cells were blocked in G1/G0 phase and could not enter S phase, and cell meiosis was inhibited. Western blot experiments showed that there was no difference in the protein expression of wnt inhibitory factor 1 (WIF1) and β-catenin in HTR8/SVneo cells between the MEHP exposure groups and the NC groups. In vitro embryo culture experiments found that there was no difference in blastocyst formation rate among groups after exposure to DEHP for 2 h. Immunofluorescence showed that the expression of WIF1 decreased in the low concentration group, and there was no difference in the medium and high concentration groups, while the expression of β-catenin was increased in both the low concentration group and the high concentration group. Our data suggest that exposure to phthalate plasticizers can affect the viability, cell cycle and apoptosis of trophoblast cells, resulting in abnormal expression of the embryonic WIF1/β-catenin signalling pathway and impaired fertility.

Porous composite hydrogels with improved MSC survival for robust epithelial sealing around implants and M2 macrophage polarization

The application of mesenchymal stem cell (MSC)-based therapy is expected to make a significant contribution to the improvement of epithelial sealing around implants. However, there is currently no optimal MSC delivery biomaterial for clinical application in peri-implant epithelium (PIE) integration. In this study, we show that injectable photo-cross-linkable porous gelatin methacryloyl (GelMA)/silk fibroin glycidyl methacrylate (SilMA) hydrogels encapsulating gingival tissue-derived MSCs (GMSCs) are a simple and practical approach for re-epithelization applications. The hydrogels played a prominent role in supporting the proliferation, survival, and spread of GMSCs. Moreover, it was found that GMSCs-laden Porous GelMA/SilMA hydrogels could significantly upregulate the hemidesmosomes (HDs)-related genes and proteins expression and promote M2 polarization while inhibiting M1 polarization in vitro. Based on a rat model of early implant placement, application of the MSC-loaded hydrogels could enhance the protein expression of LAMA3 and BP180 (COL17A1) at the implant-PIE interface and reduce horseradish peroxidase (HRP) penetration between the implants and PIE. Noticeably, hydrogel-based MSC therapy contributed to augmenting M2 macrophage infiltration at two time points in the gingival connective tissue around implants. These findings demonstrated that GMSCs-laden Porous GelMA/SilMA hydrogels could facilitate epithelial sealing around implants and M2-polarized macrophages and may be a novel and facile therapeutic strategy for implant-PIE integration. STATEMENT OF SIGNIFICANCE: In the case of poor integration between the implant and gingival epithelium, peri-implantitis can develop, which is one of the main causes of implant failure. While stem cell therapy has tremendous potential for addressing this issue, poor cell survival and engraftment compromise the effectiveness of the therapy. Due to the excellent modifiable and tunable properties of gelatin and silk fibroin, injectable photo-cross-linkable porous hydrogels were developed using gelatin methacryloyl (GelMA) and silk fibroin glycidyl methacrylate (SilMA) as delivery vehicles for gingiva-derived MSCs (GMSCs). Porous GelMA/SilMA not only enhanced the proliferation and viability of GMSCs but also promoted their immunomodulatory capability for favorable epithelial sealing around implants. Overall, GMSCs-seeded porous hydrogels could be promising strategies for re-epithelization treatment.

Shedding Light on the Role of Na,K-ATPase as a Phosphatase during Matrix-Vesicle-Mediated Mineralization

Matrix vesicles (MVs) contain the whole machinery necessary to initiate apatite formation in their lumen. We suspected that, in addition to tissue-nonspecific alkaline phosphatase (TNAP), Na,K,-ATPase (NKA) could be involved in supplying phopshate (P_i) in the early stages of MV-mediated mineralization. MVs were extracted from the growth plate cartilage of chicken embryos. Their average mean diameters were determined by Dynamic Light Scattering (DLS) (212 ± 19 nm) and by Atomic Force Microcopy (AFM) (180 ± 85 nm). The MVs had a specific activity for TNAP of 9.2 ± 4.6 U·mg^-1 confirming that the MVs were mineralization competent. The ability to hydrolyze ATP was assayed by a colorimetric method and by ³¹P NMR with and without Levamisole and SBI-425 (two TNAP inhibitors), ouabain (an NKA inhibitor), and ARL-67156 (an NTPDase1, NTPDase3 and Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) competitive inhibitor). The mineralization profile served to monitor the formation of precipitated calcium phosphate complexes, while IR spectroscopy allowed the identification of apatite. Proteoliposomes containing NKA with either dipalmitoylphosphatidylcholine (DPPC) or a mixture of 1:1 of DPPC and dipalmitoylphosphatidylethanolamine (DPPE) served to verify if the proteoliposomes were able to initiate mineral formation. Around 69-72% of the total ATP hydrolysis by MVs was inhibited by 5 mM Levamisole, which indicated that TNAP was the main enzyme hydrolyzing ATP. The addition of 0.1 mM of ARL-67156 inhibited 8-13.7% of the total ATP hydrolysis in MVs, suggesting that NTPDase1, NTPDase3, and/or NPP1 could also participate in ATP hydrolysis. Ouabain (3 mM) inhibited 3-8% of the total ATP hydrolysis by MVs, suggesting that NKA contributed only a small percentage of the total ATP hydrolysis. MVs induced mineralization via ATP hydrolysis that was significantly inhibited by Levamisole and also by cleaving TNAP from MVs, confirming that TNAP is the main enzyme hydrolyzing this substrate, while the addition of either ARL-6715 or ouabain had a lesser effect on mineralization. DPPC:DPPE (1:1)-NKA liposome in the presence of a nucleator (PS-CPLX) was more efficient in mineralizing compared with a DPPC-NKA liposome due to a better orientation of the NKA active site. Both types of proteoliposomes were able to induce apatite formation, as evidenced by the presence of the 1040 cm^-1 band. Taken together, the findings indicated that the hydrolysis of ATP was dominated by TNAP and other phosphatases present in MVs, while only 3-8% of the total hydrolysis of ATP could be attributed to NKA. It was hypothesized that the loss of Na/K asymmetry in MVs could be caused by a complete depletion of ATP inside MVs, impairing the maintenance of symmetry by NKA. Our study carried out on NKA-liposomes confirmed that NKA could contribute to mineral formation inside MVs, which might complement the known action of PHOSPHO1 in the MV lumen.

Functionalized TiCu/TiCuN coating promotes osteoporotic fracture healing by upregulating the Wnt/β-catenin pathway

Osteoporosis results in decreased bone mass and insufficient osteogenic function. Existing titanium alloy implants have insufficient osteoinductivity and delayed/incomplete fracture union can occur when used to treat osteoporotic fractures. Copper ions have good osteogenic activity, but their dose-dependent cytotoxicity limits their clinical use for bone implants. In this study, titanium alloy implants functionalized with a TiCu/TiCuN coating by arc ion plating achieved a controlled release of copper ions in vitro for 28 days. The coated alloy was co-cultured with bone marrow mesenchymal stem cells and showed excellent biocompatibility and osteoinductivity in vitro. A further exploration of the underlying mechanism by quantitative real-time polymerase chain reaction and western blotting revealed that the enhancement effects are related to the upregulation of genes and proteins (such as axin2, β-catenin, GSK-3β, p-GSK-3β, LEF1 and TCF1/TCF7) involved in the Wnt/β-catenin pathway. In vivo experiments showed that the TiCu/TiCuN coating significantly promoted osteoporotic fracture healing in a rat femur fracture model, and has good in vivo biocompatibility based on various staining results. Our study confirmed that TiCu/TiCuN-coated Ti promotes osteoporotic fracture healing associated with the Wnt pathway. Because the coating effectively accelerates the healing of osteoporotic fractures and improves bone quality, it has significant clinical application prospects.

The immune factors have complex causal regulation effects on bone mineral density

Recent evidence has gradually recognized that the immune and skeletal systems are two closely correlated systems, but the specific immune factors on bone mineral density (BMD) are largely unknown. Based on the summary-level data of genome-wide association studies (GWASs), we performed a series of analyses including two-sample Mendelian randomization (MR) analysis to test potential causal links between 731 immune traits [including median fluorescence intensities (MFIs), absolute cell (AC) counts, relative cell (RC) counts, and morphological parameters (MP)] and BMD. After false discovery rate (FDR) correction, 9 MFI-BMD, 16 AC-BMD, 22 RC-BMD, and 5 MP-BMD pairs reached the level of significance (FDR-adjusted p< 0.05). For MFI traits, the T- and B-cell panels had the largest number of significant immune trait pairs than other panels. CD40, as a molecule expressed by four subsets of monocytes, was highlighted due to its consistently positive correlation with BMD at four sites. For both AC and RC traits, immune traits from the T-cell panel were also highlighted, with CD39-positive T-cell subsets being the most frequently observed feature. For MP traits, the most significant association immune trait with BMD was SSC-A on CD14+ monocyte. Sensitivity analyses suggested that the identified immune factors were robust to pleiotropy. Multivariable MR analysis confirmed the independent causal effect of several immune traits on BMD. Mediation analyses showed that CD40 on monocytes could mediate multiple immune traits, especially the suggestive associations of CD27 on several memory B cells with BMD mediated by CD40 on CD14+ CD16- monocyte. Our study represents the first comprehensive evaluation of the causal effects of immune traits on the risk of osteoporosis. The findings highlighted the complex and important role of immune-derived factors in the pathogenesis of osteoporosis.

GSK 650394 Inhibits Osteoclasts Differentiation and Prevents Bone Loss via Promoting the Activities of Antioxidant Enzymes In Vitro and In Vivo

Osteoporosis (OP) is one of the most common bone disorders among the elderly, characterized by abnormally elevated bone resorption caused by formation and activation of osteoblast (OC). Excessive reactive oxygen species (ROS) accumulation might contribute to the formation process of OC as an essential role. Although accumulated advanced treatment target on OP have been proposed in recent years, clinical outcomes remain unexcellence attributed to severe side effects. The purpose of present study was to explore the underlying mechanisms of GSK 650394 (GSK) on inhibiting formation and activation of OC and bone resorption in vitro and in vivo. GSK could inhibit receptor activator of nuclear-κB ligand (RANKL-)-mediated Oc formation via suppressing the activation of NF-κB and MAPK signaling pathways, regulating intracellular redox status, and downregulate the expression of nuclear factor of activated T cells c1 (NFATc1). In addition, quantitative RT-PCR results show that GSK could suppress the expression of OC marker gene and antioxidant enzyme genes. Consistent with in vitro cellular results, GSK treatment improved bone density in the mouse with ovariectomized-induced bone loss according to the results of CT parameters, HE staining, and Trap staining. Furthermore, GSK treatment could enhance the capacity of antioxidant enzymes in vivo. In conclusion, this study suggested that GSK could suppress the activation of osteoclasts and therefore maybe a potential therapeutic reagent for osteoclast activation-related osteoporosis.

Botanicals and Oral Stem Cell Mediated Regeneration: A Paradigm Shift from Artificial to Biological Replacement

Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.

Adipose-Derived Stem Cell Exosomes as a Novel Anti-Inflammatory Agent and the Current Therapeutic Targets for Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA), a chronic inflammatory joint disorder, may not respond adequately to current RA treatments. Mesenchymal stem cells (MSCs) elicit several immunomodulatory and anti-inflammatory effects and, thus, have therapeutic potential. Specifically, adipose-derived stem cell (ADSC)-based RA therapy may have considerable potency in modulating the immune response, and human adipose tissue is abundant and easy to obtain. Paracrine factors, such as exosomes (Exos), contribute to ADSCs’ immunomodulatory function. ADSC-Exo-based treatment can reproduce ADSCs’ immunomodulatory function and overcome the limitations of traditional cell therapy. ADSC-Exos combined with current drug therapies may provide improved therapeutic effects. Using ADSC-Exos, instead of ADSCs, to treat RA may be a promising cell-free treatment strategy. This review summarizes the current knowledge of medical therapies, ADSC-based therapy, and ADSC-Exos for RA and discusses the anti-inflammatory properties of ADSCs and ADSC-Exos. Finally, this review highlights the expanding role and potential immunomodulatory activity of ADSC-Exos in patients with RA.

DNMT3a promotes osteoblast differentiation and alleviates osteoporosis via the PPARγ/SCD1/GLUT1 axis

Background: This study was designed to elucidate the role of DNMT3a and PPARγ functions in postmenopausal osteoporosis. Materials & methods: Mice were ovariectomized to establish an in vivo osteoporosis model and MC3T3-E1-14 osteoblasts were induced to differentiate. Gain- or loss-of-function approaches were used to manipulate the expression of PPARγ, DNMT3a and SCD1, followed by an evaluation of their role in postmenopausal osteoporosis both in vivo and in vitro. Results: DNMT3a induced methylation of the PPARγ promoter region, consequently stimulating osteoblast differentiation. PPARγ elevated SCD1, which decreased GLUT1 and inhibited osteoblast differentiation. Inhibition of PPARγ reduced SCD1 while increasing GLUT1 expression, thus alleviating postmenopausal osteoporosis in mice. Conclusion: DNMT3a promotes osteoblast differentiation and prevents postmenopausal osteoporosis by regulating the PPARγ/SCD1/GLUT1 axis.

Heterostructured Metal-Organic Frameworks/Polydopamine Coating Endows Polyetheretherketone Implants with Multimodal Osteogenicity and Photoswitchable Disinfection

Clinically, bacteria-induced contagion and insufficient osseointegrative property inevitably elicit the failure of orthopedic implants. Herein, a heterostructured coating consisting of simvastatin (SIM)-laden metal-organic frameworks and polydopamine nanolayers is created on a porous bioinert polyetheretherketone implant. The heterostructured coating significantly promotes cytocompatibility and osteogenic differentiation through multimodal osteogenicity mechanisms of zinc ion (Zn²⁺ ) therapy, SIM drug therapy, and surface micro-/nano-topological stimulation. Under the illumination of near-infrared (NIR) light, singlet oxygen (¹ O₂ ) and local hyperthermia are produced; besides, NIR light dramatically accelerates the release of Zn²⁺ ions from heterostructured coatings. Gram-positive and -negative bacteria are effectively eradicated by the synergy of photothermal/photodynamic effects and photo-induced accelerated delivery of Zn²⁺ ions. The superior osteogenicity and osseointegration, as well as photoswitchable disinfection controlled by NIR light are corroborated via in vivo results. This work highlights the great potential of photoresponsive heterostructured orthopedic implants in treatment of the noninvasive bone reconstruction of bacteria-associated infectious tissues through multimodal phototherapy and photoswitchable ion-therapy.

Mesenchymal Stromal Cells from Healthy and Inflamed Human Gingiva Respond Differently to Porphyromonas gingivalis

Gingiva-Derived Mesenchymal Stromal Cells (GMSCs) have been shown to play an important role in periodontitis. However, how P. gingivalis, one of the key etiological agents of the disease, affects healthy (H)- and periodontitis (P)-GMSCs is unknown. To address this problem, we established 10 H-GMSC and 12 P-GMSC lines. No significant differences in morphology, differentiation into chondroblasts and adipocytes, expression of characteristic MSCS markers, including pericyte antigens NG2 and PDGFR, were observed between H- and P-GMSC lines. However, proliferation, cell size and osteogenic potential were higher in P-GMSCs, in contrast to their lower ability to suppress mononuclear cell proliferation. P. gingivalis up-regulated the mRNA expression of IL-6, IL-8, MCP-1, GRO-α, RANTES, TLR-2, HIF-1α, OPG, MMP-3, SDF-1, HGF and IP-10 in P-GMSCs, whereas only IL-6, MCP-1 and GRO-α were up-regulated in H-GMSCs. The expression of MCP-1, RANTES, IP-10 and HGF was significantly higher in P-GMSCs compared to H-GMSCs, but IDO1 was lower. No significant changes in the expression of TLR-3, TLR-4, TGF-β, LAP, IGFBP4 and TIMP-1 were observed in both types of GMSCs. In conclusion, our results suggest that P-GMSCs retain their pro-inflammatory properties in culture, exhibit lower immunosuppressive potential than their healthy counterparts, and impaired regeneration-associated gene induction in culture. All these functions are potentiated significantly by P. gingivalis treatment.

Comparative proteomics analysis of human stem cells from dental gingival and periodontal ligament

Dental stem cells isolated from oral tissues have been shown to provide with high proliferation ability and multilineage differentiation potential. Gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs), kinds of dental stem cells, can be used as substitutes for tissue repair materials because of their similar regenerative functions. In this study, we aim to explore the similarities and differences between the protein profiles of GMSCs and PDLSCs through quantitative proteomics. A total of 2821 proteins were identified and retrieved, of which 271 were up-regulated and 57 were down-regulated in GMSCs compared to PDLSCs. GO analysis demonstrated that the 328 differentially abundant proteins (DAPs) were involved in the regulation of gene expression, metabolism and signal transduction in biological process, mainly distributed in organelles related to vesicle transport, and involved in the molecular function of binding protein. And KEGG analysis showed that the DAPs were committed to regulating the synthesis of proteasome and spliceosome. RT-qPCR results showed that ARPC1B, PDAP1 and SEC61B can be used as special markers to distinguish GMSCs from PDLSCs. This research contributes to explaining the molecular mechanism and promoting the clinical application of tissue regeneration of GMSCs and PDLSCs. This article is protected by copyright. All rights reserved.

Carfilzomib alleviated osteoporosis by targeting PSME1/2 to activate Wnt/β-catenin signaling

Osteoporosis (OP) is characterized by decreased bone mineral density and impaired bone strength. Carfilzomib (CFZ) is a new-generation proteasome inhibitor and has been found to affect bone metabolism. However, the effect and mechanism of CFZ on OP has not been investigated systematically. In this study, we found that protein levels of proteasome activator subunit 1/2 (PSME1/2) increased in OP, and accumulated mostly in osteoblasts and osteoclasts. Treatment with PSME1/2 recombinant protein inhibited osteogenesis and promoted osteoclast formation in vitro. Also, PSME1/2 inhibited the expression of β-catenin protein, resulting in limitation of Wnt/β-catenin signaling. CFZ inhibited PSME1 and PSME2 proteasome activities and increased β-catenin protein level, resulting in the translocation of β-catenin to the nucleus and activation of canonical Wnt/β-catenin signaling, further promoting osteogenesis and inhibiting osteoclastic differentiation. In vivo, we conducted ovariectomy (OVX) to create a model of OVX-induced postmenopausal OP in mice. When analyzed by micro-CT scanning, enhancement of bone mineral density, bone volume, trabecular number, and thickness was seen in the CFZ-treated mice. Also, we noticed increased osteogenesis and decreased osteoclastogenesis, diminished expression of PSME1 and PSME2 and activated Wnt/β-catenin signaling in bone sections from OP mice treated with CFZ. Overall, our data indicated that PSME1/2 may serve as new targets for the treatment of OP, and targeting PSME1/2 with CFZ provides a candidate therapeutic molecule for postmenopausal OP.

Wnt/β-catenin signalling: function, biological mechanisms, and therapeutic opportunities

The Wnt/β-catenin pathway comprises a family of proteins that play critical roles in embryonic development and adult tissue homeostasis. The deregulation of Wnt/β-catenin signalling often leads to various serious diseases, including cancer and non-cancer diseases. Although many articles have reviewed Wnt/β-catenin from various aspects, a systematic review encompassing the origin, composition, function, and clinical trials of the Wnt/β-catenin signalling pathway in tumour and diseases is lacking. In this article, we comprehensively review the Wnt/β-catenin pathway from the above five aspects in combination with the latest research. Finally, we propose challenges and opportunities for the development of small-molecular compounds targeting the Wnt signalling pathway in disease treatment.

Bergamottin promotes osteoblast differentiation and bone formation via activating Wnt/β-catenin signaling pathway

Osteoporosis is one of the most common bone disorders that seriously affect the health and life quality of elderly individuals. Reduced osteoblast differentiation and bone formation lead to changes in...

Barbaloin Promotes Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells: Involvement of Wnt/β-catenin Signaling Pathway

BACKGROUND

Barbaloin, found in Aloe vera, exerts broad pharmacological activities, including antioxidant, anti-inflammatory, and anti-cancer. This study aims to investigate the effects of barbaloin on the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs).

METHODS

Osteogenic induction of hBMSCs was performed in the presence or absence of barbaloin. Cell viability was determined by using the CCK-8 assay. The characteristic of hBMSCs was identified by using flow cytometry. Intracellular alkaline phosphatase (ALP) staining was performed to evaluate the ALP activity in hBMSCs. Alizarin Red S staining was performed to evaluate the matrix mineralization. The mRNA and protein levels of target genes were determined using qRT-PCR and western blotting, respectively.

RESULTS

Treatment with barbaloin (10 and 20 μg/mL) significantly increased cell viability of hBMSCs after 72 hours. In addition, treatment with barbaloin increased the mRNA expression levels of ALP and its activities. Treatment with barbaloin also increased matrix mineralization and the mRNA and protein levels of late-differentiated osteoblast marker genes BMP2, RUNX2, and SP7 in hBMSCs. The underlying mechanisms revealed that barbaloin increased the protein expressions of Wnt/β-catenin pathway-related biomarkers.

CONCLUSION

Barbaloin promotes osteogenic differentiation of hBMSCs by the regulation of the Wnt/β-catenin signaling pathway.

NTCP Deficiency Affects the Levels of Circulating Bile Acids and Induces Osteoporosis

BACKGROUND

The p.Ser267Phe mutation in the SLC10A1 gene can cause NTCP deficiency. However, the full clinical presentation of p.Ser267Phe homozygous individuals and its long-term consequences remain unclear. Hence, in the present study, we characterized the phenotypic characteristics of NTCP deficiency and evaluated its long-term prognosis.

METHODS

Ten NTCP p.Ser267Phe homozygous individuals were recruited and a comprehensive medical evaluation with a 5-year follow-up observation was performed. The phenotypic characteristics of NTCP deficiency were also demonstrated using an NTCP-global knockout mouse model.

RESULTS

During the 5-year follow-up observation of 10 NTCP p.Ser267Phe homozygous adults, we found that the most common phenotypic features of NTCP deficiency in adults were hypercholanemia, vitamin D deficiency, bone loss, and gallbladder abnormalities. The profile of bile acids (BAs) in the serum was significantly altered in these individuals and marked by both elevated proportion and concentration of primary and conjugated BAs. Moreover, the NTCP deficiency led to increased levels of serum BAs, decreased levels of vitamin D, and aggravated the osteoporotic phenotype induced by estrogen withdrawal in mice.

CONCLUSIONS

Both mice and humans with NTCP deficiency presented hypercholanemia and were more prone to vitamin D deficiency and aggravated osteoporotic phenotype. Therefore, we recommend monitoring the levels of BAs and vitamin D, bone density, and abdominal ultrasounds in individuals with NTCP deficiency.

LncRNA MALAT1 promotes osteogenic differentiation of BMSCs and inhibits osteoclastic differentiation of Mø in osteoporosis via the miR-124-3p/IGF2BP1/Wnt/β-catenin axis

Osteoporosis is defined as a skeletal disorder characterized by impairment in bone strength. The potential application of lncRNAs as therapeutic targets for osteoporosis has been unveiled. This study investigated the regulatory mechanism of lncRNA MALAT1 in the differentiation of bone marrow stem cells (BMSCs) and macrophages (Mø) in osteoporosis. MALAT1 expression in peripheral blood of elderly osteoporosis patients and healthy volunteers was detected. BMSCs and mononuclear Mø were isolated and cultured. Osteogenic differentiation of BMSCs and osteoclastic differentiation of Mø were induced. BMSCs and Mø were transfected with si-MALAT1, miR-124-3p mimics, miR-124-3p inhibitor, or pcDNA IGF2BP1, followed by detection of cell differentiation. The target microRNAs (miRs) and downstream genes and signaling pathways of MALAT1 were examined. The ovariectomy-induced mouse model of osteoporosis was established, and the mice were injected with pcDNA-MALAT1. MALAT1 was downregulated in osteoporosis patients, increased in BMSCs after osteogenic differentiation, and diminished in Mø after osteoclastic differentiation. Downregulation of MALAT1 repressed osteogenic differentiation of BMSCs and facilitated osteoclastic differentiation of Mø. MALAT1 upregulated IGF2BP1 expression by competitively binding to miR-124-3p. miR-124-3p silencing reversed the effect of si-MALAT1 on BMSCs and Mø differentiation, and IGF2BP1 upregulation averted the effect of overexpressed-miR-124-3p by activating the Wnt/β-catenin pathway. Upregulation of MALAT1 activated the Wnt/β-catenin pathway and attenuated bone injury in mice. In conclusion, lncRNA MALAT1 promoted the osteogenic differentiation of BMSCs and inhibited osteoclastic differentiation of Mø in osteoporosis via the miR-124-3p/IGF2BP1/Wnt/β-catenin axis. This article is protected by copyright. All rights reserved.

Gingival mesenchymal stem cell-derived exosomes are immunosuppressive in preventing collagen-induced arthritis

Due to the unsatisfied effects of clinical drugs used in rheumatoid arthritis (RA), investigators shifted their focus on the biotherapy. Although human gingival mesenchymal stem cells (GMSC) have the potential to be used in treating RA, GMSC‐based therapy has some inevitable side effects such as immunogenicity and tumorigenicity. As one of the most important paracrine mediators, GMSC‐derived exosomes (GMSC‐Exo) exhibit therapeutic effects via immunomodulation in a variety of disease models, bypassing potential shortcomings of the direct use of MSCs. Furthermore, exosomes are not sensitive to freezing and thawing, and can be readily available for use. GMSC‐Exo has been reported to promote tissue regeneration and wound healing, but have not been reported to be effective against autoimmune diseases. We herein compare the immunomodulatory functions of GMSC‐Exo and GMSC in collagen‐induced arthritis (CIA) model and in vitro CD4⁺ T‐cell co‐culture model. The results show that GMSC‐Exo has the same or stronger effects compared with GMSC in inhibiting IL‐17A and promoting IL‐10, reducing incidences and bone erosion of arthritis, via inhibiting IL‐17RA‐Act1‐TRAF6‐NF‐κB signal pathway. Our results suggest that GMSC‐Exo has many advantages in treating CIA, and may offer a promising new cell‐free therapy strategy for RA and other autoimmune diseases.

Role of the F-BAR Family Member PSTPIP2 in Autoinflammatory Diseases

Proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) belongs to the Fes/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain family. It exhibits lipid-binding, membrane deformation, and F-actin binding activity, suggesting broader roles at the membrane–cytoskeleton interface. PSTPIP2 is known to participate in macrophage activation, neutrophil migration, cytokine production, and osteoclast differentiation. In recent years, it has been observed to play important roles in innate immune diseases and autoinflammatory diseases (AIDs). Current research indicates that the protein tyrosine phosphatase PTP-PEST, Src homology domain-containing inositol 5’-phosphatase 1 (SHIP1), and C‐terminal Src kinase (CSK) can bind to PSTPIP2 and inhibit the development of AIDs. However, the mechanisms underlying the function of PSTPIP2 have not been fully elucidated. This article reviews the research progress and mechanisms of PSTPIP2 in AIDs. PSTPIP2 also provides a new therapeutic target for the treatment of AIDs.

Loss of Wnt16 Leads to Skeletal Deformities and Downregulation of Bone Developmental Pathway in Zebrafish

Wingless-type MMTV integration site family, member 16 (wnt16), is a wnt ligand that participates in the regulation of vertebrate skeletal development. Studies have shown that wnt16 can regulate bone metabolism, but its molecular mechanism remains largely undefined. We obtained the wnt16^−/− zebrafish model using the CRISPR-Cas9-mediated gene knockout screen with 11 bp deletion in wnt16, which led to the premature termination of amino acid translation and significantly reduced wnt16 expression, thus obtaining the wnt16^−/− zebrafish model. The expression of wnt16 in bone-related parts was detected via in situ hybridization. The head, spine, and tail exhibited significant deformities, and the bone mineral density and trabecular bone decreased in wnt16^−/− using light microscopy and micro-CT analysis. RNA sequencing was performed to explore the differentially expressed genes (DEGs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that the down-regulated DEGs are mainly concentrated in mTOR, FoxO, and VEGF pathways. Protein–protein interaction (PPI) network analysis was performed with the detected DEGs. Eight down-regulated DEGs including akt1, bnip4, ptena, vegfaa, twsg1b, prkab1a, prkab1b, and pla2g4f.2 were validated by qRT-PCR and the results were consistent with the RNA-seq data. Overall, our work provides key insights into the influence of wnt16 gene on skeletal development.

Long non‑coding RNA XIST inhibits osteoblast differentiation and promotes osteoporosis via Nrf2 hyperactivation by targeting CUL3

Osteoporosis (OP) is a common skeletal disorder characterized by a low bone mass and the deterioration of bone structure. Long non‑coding (lnc)RNA X inactive‑specific transcript (XIST) is highly expressed in the serum and monocytes of patients with OP. Thus, the purpose of the present study was to explore the mechanisms underlying the role of XIST in the progression of OP. To establish animal models of OP, female rats underwent a bilateral ovariectomy. The bone mineral density of individual rats was measured using dual‑energy X‑ray absorptiometry. The combination of XIST and cullin‑3 (CUL3) was analyzed using a dual‑luciferase reporter assay. Bone histopathological changes were assessed by hematoxylin and eosin staining. Alkaline phosphatase activity was examined by ALP staining. Finally, a series of functional experiments were performed to examine the effects of XIST on cellular behaviors. In the present study, XIST promoted OP and inhibited bone formation by regulating the expression levels of CUL3 and nuclear factor erythroid 2‑related factor 2 (Nrf2) in the rats with OP. Moreover, XIST directly targeted CUL3 and negatively regulated its expression. Of note, CUL3 downregulation reversed the effects of XIST silencing on cell viability, differentiation and mineralization, as well as the expression of Nrf2 and CUL3 in MC3T3‑E1 cells. Collectively, XIST was demonstrated to inhibit the differentiation of osteoblasts and promote OP by inhibiting the degradation of Nrf2 via targeting CUL3.

Neohesperidin promotes the osteogenic differentiation of bone mesenchymal stem cells by activating the Wnt/β-catenin signaling pathway

Background

Osteoporosis is a common disease in aging populations. However, osteoporosis treatment is still challenging. Here, we aimed to investigate the role of neohesperidin (NEO) in osteoporosis progression and the potential mechanism.

Methods

Bone mesenchymal stem cells (BMSCs) were isolated and treated with different concentrations of NEO (0, 10, 30, 100 M). Cell proliferation was analyzed by cell count kit-8 (CCK-8) assay. RNA-sequencing was performed on the isolated BMSCs with control and NEO treatment. Differentially expressed genes were obtained by R software. Alkaline phosphatase (ALP) staining and Alizarin red staining (ARS) were performed to assess the osteogenic capacity of the NEO. qRT-PCR was used to detect the expression of osteoblast markers.

Western blot was used to evaluate the protein levels in BMSCs.

Results

NEO treatment significantly improved hBMSC proliferation at different time points, particularly when cells were incubated with 30 M NEO (P < 0.05). NEO dose-dependently increased the ALP activity and calcium deposition than the control group (P < 0.05). A total of 855 differentially expressed genes were identified according to the significance criteria of log₂ (fold change) > 1 and adj P < 0.05. DKK1 partially reversed the promotion effects of NEO on osteogenic differentiation of BMSCs. NEO increased levels of the -catenin protein in BMSCs.

Conclusion

NEO plays a positive role in promoting osteogenic differentiation of BMSCs, which was related with activation of Wnt/-catenin pathway.

In Search of a Role for Extracellular Purine Enzymes in Bone Function

Bone is one of the major tissues that undergoes continuous remodeling throughout life, thus ensuring both organic body growth during development and protection of internal organs as well as repair of trauma during adulthood. Many endogenous substances contribute to bone homeostasis, including purines. Their role has increasingly emerged in recent decades as compounds which, by interacting with specific receptors, can help determine adequate responses of bone cells to physiological or pathological stimuli. Equally, it is recognized that the activity of purines is closely dependent on their interconversion or metabolic degradation ensured by a series of enzymes present at extracellular level as predominantly bound to the cell membrane or, also, as soluble isoforms. While the effects of purines mediated by their receptor interactions have sufficiently, even though not entirely, been characterized in many tissues including bone, those promoted by the extracellular enzymes providing for purine metabolism have not been. In this review, we will try to circumstantiate the presence and the role of these enzymes in bone to define their close relationship with purine activities in maintaining bone homeostasis in normal or pathological conditions.

Gingiva-Derived Mesenchymal Stem Cells: Potential Application in Tissue Engineering and Regenerative Medicine - A Comprehensive Review

A unique subpopulation of mesenchymal stem cells (MSCs) has been isolated and characterized from human gingival tissues (GMSCs). Similar to MSCs derived from other sources of tissues, e.g. bone marrow, adipose or umbilical cord, GMSCs also possess multipotent differentiation capacities and potent immunomodulatory effects on both innate and adaptive immune cells through the secretion of various types of bioactive factors with immunosuppressive and anti-inflammatory functions. Uniquely, GMSCs are highly proliferative and have the propensity to differentiate into neural cell lineages due to the neural crest-origin. These properties have endowed GMSCs with potent regenerative and therapeutic potentials in various preclinical models of human disorders, particularly, some inflammatory and autoimmune diseases, skin diseases, oral and maxillofacial disorders, and peripheral nerve injuries. All types of cells release extracellular vesicles (EVs), including exosomes, that play critical roles in cell-cell communication through their cargos containing a variety of bioactive molecules, such as proteins, nucleic acids, and lipids. Like EVs released by other sources of MSCs, GMSC-derived EVs have been shown to possess similar biological functions and therapeutic effects on several preclinical diseases models as GMSCs, thus representing a promising cell-free platform for regenerative therapy. Taken together, due to the easily accessibility and less morbidity of harvesting gingival tissues as well as the potent immunomodulatory and anti-inflammatory functions, GMSCs represent a unique source of MSCs of a neural crest-origin for potential application in tissue engineering and regenerative therapy.

Mesenchymal Stem Cell-Derived Exosomes: A Promising Biological Tool in Nanomedicine

As nano-scale biological vesicles, extracellular vesicles (EVs)/exosomes, in particular, exosomes derived from mesenchymal stem cells (MSC-exosomes), have been studied in the diagnosis, prevention, and treatment of many diseases. In addition, through the combination of nanotechnology and biotechnology, exosomes have emerged as innovative tools for the development of nanomedicine. This review focuses on a profound summarization of MSC-exosomes as a powerful tool in bionanomedicine. It systemically summarizes the role of MSC-exosomes as a nanocarrier, drug loading and tissue engineering, and their potential contribution in a series of diseases as well as the advantages of exosomes over stem cells and synthetic nanoparticles and potential disadvantages. The in-depth understanding of the functions and mechanisms of exosomes provides insights into the basic research and clinical transformation in the field of nanomedicine.

Bone Marrow and Adipose Tissue Adenosine Receptors Effect on Osteogenesis and Adipogenesis

Adenosine is an extracellular signaling molecule that is particularly relevant in times of cellular stress, inflammation and metabolic disturbances when the levels of the purine increase. Adenosine acts on two G-protein-coupled stimulatory and on two G-protein-coupled inhibitory receptors, which have varying expression profiles in different tissues and conditions, and have different affinities for the endogenous ligand. Studies point to significant roles of adenosine and its receptors in metabolic disease and bone health, implicating the receptors as potential therapeutic targets. This review will highlight our current understanding of the dichotomous effects of adenosine and its receptors on adipogenesis versus osteogenesis within the bone marrow to maintain bone health, as well as its relationship to obesity. Therapeutic implications will also be reviewed.

Ferric Ion Induction of Triggering Receptor Expressed in Myeloid Cells-2 Expression and PI3K/Akt Signaling Pathway in Preosteoclast Cells to Promote Osteoclast Differentiation

Objective

Iron plays a significant role in multiple biological processes. The purpose of this study was to measure whether iron mediated osteoclast differentiation through regulation of triggering receptor expressed in myeloid cells‐2 (Trem‐2) expression and the PI3K/Akt signaling pathway.

Methods

The effects of six different concentrations of ferric ammonium citrate (FAC) (100, 80, 40, 20, 10 and 0 μmol/L) on RAW 264.7 cells proliferation were assessed by Cell Counting Kit‐8 (CCK‐8) gassay. Tartrate resistant acid phosphatase (TRAP) assay was performed to detect the effects of FAC on osteoclast formation. The expression of osteoclast differentiation‐related (TRAP, NFATc‐1, and c‐Fos) and Trem‐2 mRNA and proteins was analyzed by reverse transcription‐polymerase chain reaction and western blot, respectively. Si‐Trem‐2 was constructed and transfected to RAW264.7 to measure the effects of Trem‐2 on FAC‐mediated osteoclast formation. TRAP assay and osteoclast differentiation‐related gene analyses were further performed to identify the role of Trem‐2 in osteoclastogenesis. The Search Tool for the Retrieval of Interacting Genes (STRING) was used to explore the target genes of Trem‐2. Trem‐2‐related gene ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were used for further in‐depth analysis. PI3K/Akt pathway‐related proteins were detected by immunofluorescence and western blot.

Results

In groups with FAC concentration of 10 (102.5 ± 3.1), 20 (100.5 ± 1.5), and 40 μmol/L (98.7 ± 3.1), compared with the control group (100.1 ± 2.2), cell viability was not significantly different from the control (P > 0.05). When the concentration of FAC exceeded 80 μmol/L, cell viability was significantly decreased (87.5 ± 2.8 vs 100.1 ± 2.2, P < 0.05). FAC promotes Trem‐2 expression and osteoclast differentiation in a dose‐response manner (P < 0.05). The number of osteoclast‐like cells was found to be reduced following transfection with the siRNA of Trem‐2 (42 ± 3 vs 30 ± 5, P < 0.05). We observed that most of Trem‐2 target genes are primarily involved in response to organic substance, regulation of reactive oxygen species metabolic process, and regulation of protein phosphorylation. The STRING database revealed that Trem‐2 directly target two gene nodes (Pik3ca and Pik3r1), which are key transcriptional cofactors of the PI3K/Akt signaling pathway. KEGG pathways include the “PI3K‐Akt signaling pathway,” the “thyroid hormone signaling pathway”, “prostate cancer,” the “longevity regulating pathway,” and “insulin resistance.” Expression of p‐PI3K and p‐Akt protein, measured by immunofluorescence and western blotting, was markedly increased in the FAC groups. Trem‐2 siRNA caused partial reduction of these two proteins (p‐PI3K and p‐Akt) compared to the FAC alone group.

Conclusion

The FAC promoted osteoclast differentiation through the Trem‐2‐mediated PI3K/Akt signaling pathway. However, its regulation osteoclastogenesis should be verified through further in vivo studies.

B7-H1 Promotes the Functional Effect of Human Gingiva-Derived Mesenchymal Stem Cells on Collagen-Induced Arthritis Murine Model

Recent studies found that mesenchymal stem cells (MSCs), by virtue of their tissue recovery and immunoregulatory properties, have shown a broad prospect for applications in various autoimmune and degenerative diseases. Although the potential therapeutic use of MSCs is considerable, studies and clinical treatment efficacy are preliminary due to the heterogeneity of MSCs. Herein, based on RNA-sequencing (RNA-seq) and single cell sequence properties, we demonstrated that B7-H1 plays an important role in the immunosuppressive function of human gingiva-derived mesenchymal stem cells (GMSCs) in a collagen-induced arthritis murine model that is dependent on STAT3 signaling. Our data offer convincing evidence that B7-H1 expression by GMSCs helps to identify a new subpopulation of MSCs with a greater immunosuppressive property. The approach provides a unique and additional strategy for stem cells-based therapies of autoimmune and other inflammatory diseases.

Human gingiva-derived mesenchymal stem cells are therapeutic in lupus nephritis through targeting of CD39-CD73 signaling pathway

Cell specific and cytokine targeted therapeutics have underperformed in systemic lupus erythematosus (SLE). Mesenchymal stem cells (MSCs) have emerged as a novel therapy to address the dysregulation in autoimmune diseases but also have limitations. Human gingiva derived MSCs (GMSCs) are superior in regulating immune responses. Here, we demonstrate that the adoptive transfer of GMSCs homes to and maintains in the kidney and has a robust therapeutic effect in a spontaneous lupus nephritis model. Specifically, GMSCs limits the development of autoantibodies as well as proteinuria, decreases the frequency of plasma cells and lupus nephritis histopathological scores by directly suppressing B cells activation, proliferation and differentiation. The blockage of CD39^-CD73 pathway dramatically abrogates the suppressive capacities of GMSCs in vitro and in vivo and highlights the significance of this signaling pathway in SLE. Collectively, manipulation of GMSCs provides a promising strategy for the treatment of patients with SLE and other autoimmune diseases.