Alkaline Phosphatase Expression Research Articles

Odontogenic and anti-inflammatory effects of magnesium-doped bioactive glass in vital pulp therapy.

This study aimed to investigate the effects of magnesium-doped bioactive glass (Mg-BG) on the mineralization, odontogenesis, and anti-inflammatory abilities of human dental pulp stem cells (hDPSCs). Mg-BG powders with different Mg concentrations were successfully synthesized via the sol-gel method and evaluated using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Apatite formation was observed on the surfaces of the materials after soaking in simulated body fluid. hDPSCs were cultured with Mg-BG powder extracts in vitro, and no evident cytotoxicity was observed. Mg-BG induced alkaline phosphatase (ALP) expression and mineralization of hDPSCs and upregulated the expression of odontogenic genes, including those encoding dentin sialophosphoprotein, dentin matrix protein 1, ALP, osteocalcin, and runt-related transcription factor 2. Moreover, secretion of inflammatory cytokines (interleukin [IL]-4, IL-6, IL-8, and tumor necrosis factor-alpha) was substantially suppressed by Mg-BG. Collectively, the results of this study suggest that Mg-BG has excellent in vitro bioactivity and is a potential material for vital pulp therapy for inflamed pulps.

Degradation behavior and osteogenic activity of octacalcium phosphate modified MgO coatings on magnesium

To further enhance the corrosion resistance and osteogenic activity of the porous micro-arc oxidation (MAO) derived MgO ceramic coating on biomedical magnesium (Mg), octacalcium phosphate (OCP) layers with different microstucture were prepared on MAO coating by chemical deposition (CD) method to fabricate MAO/CD composite coatings. The in vitro degradation behaviors of MAO/CD-coated samples were evaluated by immersion in simulated body fluid (SBF) and electrochemical impedance spectroscopy (EIS) measurement. Their effects on in vitro MC3T3-E1 cell differentiation were investigated by examining alkaline phosphatase (ALP) activity and expression of main osteogenic-related genes. The in vitro immersion tests show that MAO/CD coatings rarely experience destruction and only micro-cracks occur after 96 h. EIS tests indicate that MAO/CD coatings slow down the degradation rate of Mg observably. In addition, MAO/CD coatings improve osteogenic differentiation of MC3T3-E1 cells compared to MAO coating, which is ascribed the lightened alkalization of the surrounding medium as well as up-regulated intracellular Ca2+. MAO/CD coating deposited in 2 h endows Mg the slowest degradation rate and excellent osteogenic differentiation induction activity.

Delivery of miRNAs Using Porous Silicon Nanoparticles Incorporated into 3D Hydrogels Enhances MSC Osteogenesis by Modulation of Fatty Acid Signaling and Silicon Degradation.

Strategies incorporating mesenchymal stromal cells (MSC), hydrogels and osteoinductive signals offer promise for bone repair. Osteoinductive signals such as growth factors face challenges in clinical translation due to their high cost, low stability and immunogenicity leading to interest in microRNAs as a simple, inexpensive and powerful alternative. The selection of appropriate miRNA candidates and their efficient delivery must be optimised to make this a reality. This study evaluated pro-osteogenic miRNAs and used porous silicon nanoparticles modified with polyamidoamine dendrimers (PAMAM-pSiNP) to deliver these to MSC encapsulated within gelatin-PEG hydrogels. miR-29b-3p, miR-101-3p and miR-125b-5p are strongly pro-osteogenic and are shown to target FASN and ELOVL4 in the fatty acid biosynthesis pathway to modulate MSC osteogenesis. Hydrogel delivery of miRNA:PAMAM-pSiNP complexes enhanced transfection compared to 2D. The osteogenic potential of hBMSC in hydrogels with miR125b:PAMAM-pSiNP complexes is evaluated. Importantly, a dual-effect on osteogenesis occurred, with miRNAs increasing expression of alkaline phosphatase (ALP) and Runt-related transcription factor 2 (RUNX2) whilst the pSiNPs enhanced mineralisation, likely via degradation into silicic acid. Overall, this work presents insights into the role of miRNAs and fatty acid signalling in osteogenesis, providing future targets to improve bone formation and a promising system to enhance bone tissue engineering.

Immunohistochemical study of mixing mineral trioxide aggregate with hyaluronic acid as a pulp-capping agent in dog teeth

Objective: The purpose of this study was to evaluate the immunohistochemical effect of hyaluronic acid (HA) on the mineralization rate of the reparative dentin when it is used as a mixing medium with mineral trioxide aggregate (MTA). Materials and Methods: Direct pulp capping (DPC) was performed on 90 teeth from 10 dogs that had been experimentally exposed. The exposed pulps were divided into three groups according to the mixing medium with MTA: Group I: MTA + distilled water (control group), Group II: MTA + hybrid cooperative complex HA (HCC-HA), Group III: MTA + high molecular weight HA (HMW-HA). After pulp capping, all cavities were restored with final restoration. The dogs were divided randomly into five groups (two dogs each) according to the evaluation periods (7, 14, 21, 30, and 60) days. At the end of the study, the dogs were euthanized, and the sampled teeth were processed for immunohistochemical investigation. Results: Both types of HA (HCC-HA, HMW-HA) showed an increase in the expression of alkaline phosphatase (ALP) at a higher rate than using distilled water with MTA. Conclusions: Within the limitations of this study, HA proved to be an effective additive to MTA for DPC.

Beta-adrenergic receptor antagonist propranolol prevents bisphosphonate-related osteonecrosis of the jaw by promoting osteogenesis

Background/purposeBisphosphonate-related osteonecrosis of the jaw (BRONJ), a complication arising from the use of bisphosphonates (BPs), inflicts long-term suffering on patients. Currently, there is still a lack of effective treatments. This study aimed to explore the preventive effects of propranolol (PRO) on BRONJ in vitro and in vivo, given PRO's potential in bone health enhancement. Materials and methodsIn vitro, effect of PRO on zoledronic acid (ZA)-pretreated bone marrow mesenchymal stem cells (BMSCs) was detected by cell counting kit-8, alkaline phosphatase (ALP) staining, alizarin red staining, real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot. In vivo, forty mice were divided into four groups: control, ZA, PRO, and ZA-PRO. The maxillary extraction sockets sides were analyzed with micro-CT and histomorphometry. Hematoxylin-eosin (H&E), Masson staining, immunofluorescence staining of ALP, bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (RUNX2) and TUNEL staining were performed. ResultsPRO increased proliferation and osteogenic differentiation of BMSCs. PRO stimulated bone formation and facilitated the healing process in zoledronic acid-induced osteonecrosis of jaw in mouse model. Compared with ZA group, control and PRO group showed more BMP2+, RUNX2+, and ALP+ cells (P < 0.05). However, PRO rescued the decreased expression of ALP, RUNX2, BMP2 due to ZA and decreased the expression of TUNEL (P < 0.05). ConclusionThe findings suggest that propranolol may offer a promising preventive strategy against BRONJ by enhancing bone regeneration. This research contributes to the understanding of the pathogenesis of BRONJ and opens avenues for potential treatments of BRONJ focusing on β-adrenergic signaling.

Carbon nanotubes induce mineralization of human cementoblasts

Carbon nanotubes induce mineralization of human cementoblasts

Bone-derived PDGF-BB enhances hippocampal non-specific transcytosis through microglia-endothelial crosstalk in HFD-induced metabolic syndrome

BackgroundIt is well known that high-fat diet (HFD)-induced metabolic syndrome plays a crucial role in cognitive decline and brain-blood barrier (BBB) breakdown. However, whether the bone-brain axis participates in this pathological process remains unknown. Here, we report that platelet-derived growth factor-BB (PDGF-BB) secretion by preosteoclasts in the bone accelerates neuroinflammation. The expression of alkaline phosphatase (ALPL), a nonspecific transcytosis marker, was upregulated during HFD challenge.Main bodyPreosteoclast-specific Pdgfb transgenic mice with high PDGF-BB concentrations in the circulation recapitulated the HFD-induced neuroinflammation and transcytosis shift. Preosteoclast-specific Pdgfb knockout mice were partially rescued from hippocampal neuroinflammation and transcytosis shifts in HFD-challenged mice. HFD-induced PDGF-BB elevation aggravated microglia-associated neuroinflammation and interleukin-1β (IL-1β) secretion, which increased ALPL expression and transcytosis shift through enhancing protein 1 (SP1) translocation in endothelial cells.ConclusionOur findings confirm the role of bone-secreted PDGF-BB in neuroinflammation and the transcytosis shift in the hippocampal region during HFD challenge and identify a novel mechanism of microglia-endothelial crosstalk in HFD-induced metabolic syndrome.

Enhanced osteogenic differentiation potential of Arnica montana and Bellis perennis in C3H10T1/2 multipotent mesenchymal stem cells.

Arnica montanaandBellis perennisare two medicinal plants that are thought to accelerate bone repair in homoeopathic literature. Mesenchymal stem cells (MSCs) are multipotent stem cells with the ability to differentiate and regenerate bone or osteogenesis.Hence, we aimed to determine the role ofArnica montanaandBellis perennison the osteogenic differentiation of the C3H10T1/2 stem cell line. The cell proliferation ofArnica montanaandBellis perenniswas evaluated by MTT assay. Osteogenic differentiation of C3H10T1/2 was induced by the addition of β-glycerophosphate, ascorbic acid and dexamethasone in the differentiation medium over 3 weeks. Cells were treated with Arnica montana andBellis perennis individually as well as in combination. The osteogenic differentiation potential ofArnica montana andBellis perennis to differentiate C3H10T1/2 into osteoblasts was measured by alkaline phosphatase activity, alizarin red staining and the expression of Osteocalcin using immunostaining and qRT-PCR. Arnica montana and Bellis perennis could enhance C3H10T1/2 cell proliferation at 1600µg. Further, the compound showed the ability to augment osteogenesis as confirmed by increased expression of alkaline phosphatase and enhanced calcium accumulation as seen by the Alizarin Red staining and quantification. Enhanced osteogenesis was further supported by the increased expression of osteocalcin in the treated cells with individual and combined doses of Arnica montana and Bellis perennis. Therefore, the findings provide additional support for the positive impact of Arnica montana and Bellis perennis on bone formation. Our findings suggest that homoeopathic compoundsArnica montanaandBellis perenniscan augment osteogenesis individually as well as in combination.

The effect of cigarette and e-cigarette smoke on dental pulp stem cells proliferation capacity and differentiation [in vitro study]

BackgroundMesenchymal stem cells (MSCs) have long been known for their ability to regenerate tissue. Cigarette smoking is one environmental risk factor that may impair the performance of MSCs. Electronic cigarettes have recently become a popular and widely accepted alternative to tobacco cigarettes due to their safety. The present study aims to analyze how smoke extracts of cigarette tobacco and electronic cigarettes affect the capability of dental pulp stem cell (DPSCs) proliferation and osteogenic differentiation. In this study, DPSCs were isolated from healthy impacted third molars of non-smokers, and two smoke extracts were made from tobacco powder and electronic cigarettes. Half maximal inhibitory concentration (IC50) was calculated at two time intervals (14 and 21 days), and its effect on the proliferation and osteogenic differentiation of the DPSCs was assessed.ResultsThe proliferation rate with the calculated IC50 of both smoke extracts was reduced compared to control cells. After 21 days of osteogenic induction, significantly fewer calcium deposits were visible among cells exposed to both smoke extracts. In addition, the expression of alkaline phosphatase and RANKL proteins was significantly reduced in differentiated DPSCs subjected to both smoke extracts.ConclusionsDPSCs exposed to both smoke extracts showed decreased cell viability and osteogenic differentiation potentiality compared to control cells. Smoking in any form has a detrimental effect on the proliferation and regenerative capacity of MSCs.

Mogroside V Promotes Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells from Diabetic Mice by Altering MicroRNA Profiles.

Mogroside V (MV), a triterpene glycoside, exhibits diverse biological functions. However, its ability to promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) under diabetic conditions is yet to be elucidated. To study the regulation of osteogenic differentiation of BMSCs in diabetic mice by MV and determine the potential mechanism. BMSCs were isolated from both normal (referred to as N-BMSCs) and diabetic (referred to as DM-BMSCs) C57BL/6 mice. DM-BMSCs were treated with different concentrations of MV for varying durations, and cell viability was detected using the cell counting kit-8 assay. Following 2 weeks of osteogenic induction, osteogenic differentiation capability was evaluated using alizarin red S staining, alkaline phosphatase (ALP) activity analysis, and quantitative real-time reverse transcription polymerase chain reaction. Furthermore, the microRNA (miRNA) expression profiles of N-BMSCs, DM-BMSCs, and DM-BMSCs treated with MV were tested using high-throughput sequencing. Treatment with MV enhanced the viability of DM-BMSCs and mitigated the reduction of calcium nodule deposition, ALP activity, and mRNA expression of ALP, osteocalcin, and runt-related transcription factor 2. Of the analyzed miRNAs, miR-10b-5p was the only one that exhibited differential expression in N-BMSCs, DM-BMSCs, and DM-BMSCs treated with MV. An analysis of the top four protein clusters based on KEGG suggested that the target genes of differentially expressed miRNAs were closely linked to the PI3K/AKT pathway. MV significantly enhances the viability and osteogenic differentiation of BMSCs under diabetic conditions. The alteration of miRNA profiles provides a foundation for further research into the regulatory role of miRNAs and MV in this process.

Lithium-Doped Titanium Dioxide-Based Multilayer Hierarchical Structure for Accelerating Nerve-Induced Bone Regeneration.

Despite considerable advances in artificial bone tissues, the absence of neural network reconstruction in their design often leads to delayed or ineffective bone healing. Hence, we propose a multilayer hierarchical lithium (Li)-doped titanium dioxide structure, constructed through microarc oxidation combined with alkaline heat treatment. This structure can induce the sustained release of Li ions, mimicking the environment of neurogenic osteogenesis characterized by high brain-derived neurotrophic factor (BDNF) expression. During in vitro experiments, the structure enhanced the differentiation of Schwann cells (SCs) and the growth of human umbilical vein endothelial cells (HUVECs) and mouse embryo osteoblast progenitor cells (MC3T3-E1). Additionally, in a coculture system, the SC-conditioned media markedly increased alkaline phosphatase expression and the formation of calcium nodules, demonstrating the excellent potential of the material for nerve-induced bone regeneration. In an in vivo experiment based on a rat distal femoral lesion model, the structure substantially enhanced bone healing by increasing the density of the neural network in the tissue around the implant. In conclusion, this study elucidates the neuromodulatory pathways involved in bone regeneration, providing a promising method for addressing bone deformities.

CA1 Modulates the Osteogenic Differentiation of Dental Follicle Stem Cells by Activating the BMP Signaling Pathway In Vitro.

Carbonic anhydrase 1 (CA1) has been found to be involved in osteogenesis and osteoclast in various human diseases, but the molecular mechanisms are not completely understood. In this study, we aim to use siRNA and lentivirus to reduce or increase the expression of CA1 in Dental follicle stem cells (DFSCs), in order to further elucidate the role and mechanism of CA1 in osteogenesis, and provide better osteogenic growth factors and stem cell selection for the application of bone tissue engineering in alveolar bone fracture transplantation. The study used RNA interference and lentiviral vectors to manipulate the expression of the CA1 gene in DFSCs during in vitro osteogenic induction. The expression of osteogenic marker genes was evaluated and changes in CA1, alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and Bone morphogenetic proteins (BMP2) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB). The osteogenic effect was assessed through Alizarin Red staining. The mRNA and protein expression levels of CA1, ALP, RUNX2, and BMP2 decreased distinctly in the si-CA1 group than other groups (p < 0.05). In the Lentivirus-CA1 (LV-CA1) group, the mRNA and protein expressions of CA1, ALP, RUNX2, and BMP2 were amplified to varying degrees than other groups (p < 0.05). Apart from CA1, BMP2 (43.01%) and ALP (36.69%) showed significant upregulation (p < 0.05). Alizarin red staining indicated that the LV-CA1 group produced more calcified nodules than other groups, with a higher optical density (p < 0.05), and the osteogenic effect was superior. CA1 can impact osteogenic differentiation via BMP related signaling pathways, positioning itself upstream in osteogenic signaling pathways, and closely linked to osteoblast calcification and ossification processes.

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

Mori Radicis Cortex (MRC) is the root bark of the mulberry family as Morus alba L. In Korea, it is known as "Sangbaegpi". While MRC has demonstrated anti-inflammatory and antioxidant effects, its specific mechanisms of action and impact on osteoporosis remain poorly understood. To investigate the anti-osteoporosis 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 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. 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 nuclear factor of activated T cells 1 (NFATc1)/ and c-Fos, and suppressed the mRNA expression. 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.

Polylysine-derived carbon quantum dots modulate T lymphocyte responses for periodontitis treatment

Periodontitis, a common chronic inflammatory disease, is characterized by T cell responses leading to gradual alveolar bone loss and eventual tooth mobility or loss. Herein, polylysine-derived carbon quantum dots (PLL-CQDs) are synthesized via the pyrolysis method to facilitate the recovery of periodontal bone loss induced by periodontitis by modulating T cell phenotype. The PLL-CQDs, characterized by small particle size (2.31 ± 0.70 nm) and fluorescence properties, preserved the positive charge of PLL, affirming successful preparation. In vitro studies revealed that PLL-CQDs significantly increased T cell proliferation in a concentration-dependent manner, while effectively suppressing differentiation into CD4+ phenotype. Furthermore, they promoted alkaline phosphatase expression and calcium nodule formation in MC3T3-E1 cells, indicating potential for periodontal bone regeneration. In vivo experiments demonstrated that PLL-CQDs mitigated alveolar bone resorption and modulated periodontal tissue inflammation. Overall, PLL-CQDs exhibited the ability to regulate T cell differentiation and expedite periodontal bone healing, offering promising implications for periodontitis treatment and suggesting novel strategies for addressing immune-associated bone diseases using CQDs.

[Senolytic effects on dental pulp stem cell's proliferation and differentiation during long-term expansion].

Objective: To investigate the impact of intermittent senescent cell clearance on the proliferation and differentiation of dental pulp stem cells (DPSC) in long-term, large-scale expansion, and to explore strategies for maintaining the youthful state of DPSC in vitro. Methods: Human-derived dental pulp stem cells were isolated from healthy permanent teeth extracted for orthodontic or impeding eruption reasons, provided by the Department of Oral and Maxillofacial Surgery at West China Hospital of Stomatology, Sichuan University. Long-term, large-scale in vitro expansion of DPSC was conducted. The study compared young DPSC (passage 5) with aged DPSC (passage 25) using cellular senescence-associated β-galactosidase staining, colony formation assay, and Alizarin Red S staining for osteogenic differentiation induction. To assess the differences between the two cell populations in terms of senescence and amplification and differentiation ability. Medicine screening for the most effective senolytic was compared among 5 common senolytics [Navitoclax (ABT-263), curcumin, dasatinib, fisetin, and quercetin]. The clearance efficacy was compared using cellular senescence-associated β-galactosidase staining to reflect the changes in senescent cell ratio. The senolytic with the highest efficacy was chosen for further experiments. The passage at which the proportion of senescent cells significantly increased was identified, and the selected senolytic was administered three times at three-generation intervals from that passage to remove senescent cells. Both the control and senolytic-treated groups were estimated by fluorescence cellular senescence-associated β-galactosidase staining, real-time flurogenic quantitative PCR (qPCR), colony formation assay, wound healing assay, and Alizarin Red S staining for osteogenic differentiation induction. Subcutaneous heterotopic osteogenesis was performed in nude mice and the grafts were analyzed by HE staining and alkaline phosphatase (ALP) immunohistochemical staining. Results: The proportion of senescent cells increased as the expansion extended, leading to decreased proliferation and osteogenic differentiation ability of senescent DPSC compared to young DPSC (P<0.05). Senescent DPSC exhibited altered mRNA expression levels of senescence-related genes, including p21, p16INK4a, IL-6, and Ki67 (P<0.001). Among the five senolytics, ABT-263 demonstrated higher clearance efficiency (P<0.05). After intermittent ABT-263 treatment during expansion, the proportion of senescent cells in the senolytic-treated group [(6.72±2.34)%] was significantly lower than that in the control group [(31.82±0.57)%] (P<0.001). qPCR confirmed that compared with the control group, mRNA expressions of p21, p16INK4a, and IL-6 in the senolytic-treated group were significantly decreased (P<0.05), while mRNA expressions of Ki67 were significantly increased (P<0.01). Furthermore, the cell healing ability and osteogenic differentiation ability of the senolytic-treated group were higher than those of the control group (P<0.05). In vivo experimental results indicated that the relative new bone area [(2.36±0.48)%] after DPSC transplantation in the senolytic-treated group was greater than that in the control group [(1.00±0.46)%] (P<0.05), and the expression of ALP was higher than that in the control group (P<0.01). Conclusions: ABT-263 can effectively eliminate senescent cells in long-term large-scale DPSC expansion. Continuous: treatment with ABT-263 during cultivation can maintain the proliferation and differentiation ability of DPSC both in vivo and in vitro.

BMP7-induced osteoblast differentiation requires hedgehog signaling and involves nuclear mechanisms of gene expression control.

During the morphological changes occurring in osteoblast differentiation, Sonic hedgehog (Shh) plays a crucial role. While some progress has been made in understanding this process, the epigenetic mechanisms governing the expression of Hh signaling members in response to bone morphogenetic protein 7 (BMP7) signaling in osteoblasts remain poorly understood. To delve deeper into this issue, we treated pre-osteoblasts (pObs) with 100 ng/mL of BMP7 for up to 21 days. Initially, we validated the osteogenic phenotype by confirming elevated expression of well-defined gene biomarkers, including Runx2, Osterix, Alkaline Phosphatase (Alp), and bone sialoprotein (Bsp). Simultaneously, Hh signaling-related members Sonic (Shh), Indian (Ihh), and Desert (Dhh) Hedgehog (Hh) exhibited nuanced modulation over the 21 days in vitro period. Subsequently, we evaluated epigenetic markers, and our data revealed a notable change in the CpG methylation profile, considering the methylation/hydroxymethylation ratio. CpG methylation is a reversible process regulated by DNA methyltransferases and demethylases, including Ten-eleven translocation (Tets), which also exhibited changes during the acquisition of the osteogenic phenotype. Specifically, we measured the methylation pattern of Shh-related genes and demonstrated a positive Pearson correlation for GLI Family Zinc Finger 1 (Gli1) and Patched (Ptch1). This data underscores the significance of the epigenetic machinery in modulating the BMP7-induced osteogenic phenotype by influencing the activity of Shh-related genes. In conclusion, this study highlights the positive impact of epigenetic control on the expression of genes related to hedgehog signaling during the morphogenetic changes induced by BMP7 signaling in osteoblasts.

Osteogenerative and corrosion-decelerating teriparatide-mediated strontium–zinc phosphate hybrid coating on biodegradable zinc–copper alloy for orthopaedic applications

Zinc–copper (ZnCu) alloys recently showed great potential as biodegradable materials for bone implants thanks to their excellent mechanical strength, biosafety, and promising bioactivities. However, bare ZnCu alloys exhibited poor cytocompatibility and osteointegration. Moreover, the biological functions of ZnCu remain to be corroborated. Herein, the teriparatide (PTH)-mediated strontium–zinc phosphate (SrZnP) organic–inorganic hybrid coating was fabricated on the surface of ZnCu substrate via a chemical conversion method to contain the release of Zn ions and improve biofunctionality in osteogenesis. The characteristics of the hybrid coating were optimised by adjusting the amount of PTH molecules added. A dense and homogenous coating with micellar crystal micro-/nano-structure was obtained. The coated samples showed a significantly decreased corrosion rate and a more uniform corrosion mode, effectively suppressing the release of Zn2+. Additionally, the coated ZnCu enhanced the proliferation of bone marrow mesenchymal stem cells (BMSCs), promoted the expression of alkaline phosphatase and the formation of calcium nodules, and upregulated the levels of osteogenic-related genes. More important, the hybrid coating activated the classic osteogenic signalling pathway of BMP-2/Smad1/Runx2 and Sirt1/Runx2 to induce the osteogenic differentiation of BMSCs. These appealing features can be mainly attributed to the constituents of released Zn2+, Sr2+, and PTH molecules in the control, as well as the unique topographical characteristics of the coatings. Taken together, the PTH&SrZnP hybrid coating could be a promising option for surface modification of biodegradable metallic Zn for orthopaedic applications.

Using Integrated Multi-Omics to Explore the Differences in the Three Developmental Stages of Thelephora ganbajun Zang

Thelephora ganbajun Zang, a rare wild macrofungus, has significant culinary and medicinal value. However, it also has a high cost attributed to its inability to achieve artificial cultivation and its strict environmental requirements. To reveal the intricacies of its development, we conducted a comprehensive analysis of the proteome and metabolome in three pivotal developmental stages: the mycelium, the primordium, and the fruiting body. In our investigation, genes exhibiting various expression levels across multi-omics analyses were identified as potential candidates implicated in growth, development, or metabolic regulation. The aim of this study was to provide a clearer direction for understanding the fundamental metabolic activities and growth stages of this species. Label-free proteomic sequencing revealed a critical juncture in ectomycorrhiza formation, particularly during the transition from the mycelium to the primordium. Secreted proteins, signaling proteins, membrane proteins, and proteins with unidentified functions were rapidly synthesized, with certain amino acids contributing to the synthesis of proteins involved in signaling pathways or hormone precursor substances. In the metabolomics analysis, the classification of secondary metabolites revealed a noteworthy increase in lipid substances and organic acids, contributing to cell activity. The early mycelial development stage exhibited vigorous cell metabolism, contrasting with a decline in cell division activity during fruiting body formation. In our findings, the integration of metabolomic and transcriptomic data highlighted the potential key role of folate biosynthesis in regulating early ectomycorrhiza development. Notably, the expression of alkaline phosphatase and dihydrofolate synthase genes within this pathway was significantly up-regulated in the mycelium and fruiting body stages but down-regulated in the primordium stage. This regulation primarily influences dihydrofolate reductase activity and B vitamin synthesis.

Cardamonin inhibits osteogenic differentiation by downregulating Wnt/beta-catenin signaling and alleviates subchondral osteosclerosis in osteoarthritic mice.

Osteoarthritis (OA) is a common degenerative joint disease, and subchondral osteosclerosis is an important pathological change that occurs in its late stages. Cardamonin (CD) is a natural flavonoid isolated from Alpinia katsumadai that has anti-inflammatory activity. The objectives of this study were to investigate the therapeutic effects and potential mechanism of CD in regulating OA subchondral osteosclerosis at in vivo and in vitro settings. Eight-week-old male C57BL/6J mice were randomly divided into four groups: sham operation, anterior cruciate ligament transection (ACLT)-induced OA model, low-dose and high-dose CD treated ACLT-OA model groups. Histological assessment and immunohistochemical examinations for chondrocyte metabolism-related markers metalloproteinase-13, ADAMTS-4, Col II, and Sox-9 were performed. Microcomputed tomography was used to assess the sclerosis indicators in subchondral bone. Further, MC3T3-E1 (a mouse calvarial preosteoblast cell line) cells were treated with various concentrations of CD to reveal the influence and potential molecular pathways of CD in osteogenic differentiations. Animal studies suggested that CD alleviated the pathological changes in OA mice such as maintaining integrity and increasing the thickness of hyaline cartilage, decreasing the thickness of calcified cartilage, decreasing the Osteoarthritis Research Society International score, regulating articular cartilage metabolism, and inhibiting subchondral osteosclerosis. In vitro investigation indicated that CD inhibited alkaline phosphatase expression and production of calcium nodules during osteogenic differentiation of MC3T3-E1 cells. In addition, CD inhibited the expression of osteogenic differentiation-related indicators and Wnt/β-catenin pathway-related proteins. In conclusion, CD inhibits osteogenic differentiation by downregulating Wnt/β-catenin signaling and alleviating subchondral osteosclerosis in a mouse model of OA.

Abstract 2761: Activating RET mutations promotes osteoblastic bone metastasis by inhibiting osteoclastogenesis and stimulating osteoblast activity via regulation of osteoprotegerin

Abstract Bone metastases (BM) are a source of increased mortality and significant morbidity in patients with medullary thyroid cancer (MTC), with ~50% survival at five years post-diagnosis. MTC causes osteoblastic, osteolytic, or mixed lesions, yet the underlying mechanisms are unknown. The RET proto-oncogene encodes a transmembrane tyrosine kinase receptor and is the driver oncogene in ~60% of MTC cases where a germline or somatic activating mutation results in ligand-independent constitutive activation of the receptor. However, the role of RET mutations in the genesis of bone metastasis lesions is unknown. We show that activating RET mutations promotes an osteoblastic phenotype in mice implanted with patient-derived MTC cells by increasing bone formation and decreasing bone resorption. We found that the radiographic appearance of osteoblastic lesions differed between the types of RET mutations (C634W and M918T). MTC cells with RETC634W mutation showed a four-fold increase in bone mineral density, trabecular bone volume, number, and thickness with a decreased number of osteoblasts compared to the non-tumor-bearing femur. TRAP staining revealed that osteoclast numbers per long bone were reduced in the injected femur compared to the control. In contrast, the MTC-RETM918T mutation showed an increased cortical thickness and porosity with reduced medullary area and increased bone formation rate compared to the non-tumor bearing femur. MTC cells formed tumors with extensive mineralized tissue, composed of bone matrix surrounded by osteoblast-like cells and osteoid. The knockdown of RET in the MTC-RETM918T model significantly reduced cortical thickness and increased the number of osteoclasts per bone surface. We observed increased osteoprotegerin (OPG) expression in MTC-bearing femurs compared to controls, suggesting decreased bone resorption. The factors secreted by MTC cells, including OPG, inhibited osteoclast formation from primary bone marrow cells and Raw264 cells. In addition, RET knockdown by shRNA in MTC cells decreased OPG expression. Moreover, the MTC-conditioned media (CM) increased osteoblast differentiation and mineralization of the primary culture of pre-osteoblasts isolated from calvarial bone, long bones, and MC3T3 cells. The conditioned media of RET-depleted cells inhibits osteoblast differentiation and mineralization. The expression of alkaline phosphatase, osteocalcin, OPG, and osterix increased in pre-osteoblast incubated with MTC-CM. Compared to primary non-metastatic tumors, the OPG expression increases in tissues of sporadic MTC bone metastases harboring RETM918T mutation. These results suggest that MTC with RET-activating mutations induces osteoblastic bone metastasis due to decreased bone resorption and increased bone formation. Citation Format: Rozita Bagheri-Yarmand, Joseph L. Kidd, Gabriel M. Pagnotti, Trupti Trivedi, Leah Guerra, Xinhai Wan, Jian Song, Sue-Hwa Lin, Theresa A Guise. Activating RET mutations promotes osteoblastic bone metastasis by inhibiting osteoclastogenesis and stimulating osteoblast activity via regulation of osteoprotegerin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2761.