Small Joint Organoids 3D Bioprinting: Construction Strategy and Application.

Osteoarthritis (OA) is a chronic disease that causes pain and disability in adults, affecting ≈300 million people worldwide. It is caused by damage to cartilage, including cellular inflammation and destruction of the extracellular matrix (ECM), leading to limited self-repairing ability due to the lack of blood vessels and nerves in the cartilage tissue. Organoid technology has emerged as a promising approach for cartilage repair, but constructing joint organoids with their complex structures and special mechanisms is still challenging. To overcome these boundaries, 3D bioprinting technology allows for the precise design of physiologically relevant joint organoids, including shape, structure, mechanical properties, cellular arrangement, and biological cues to mimic natural joint tissue. In this review, the authors will introduce the biological structure of joint tissues, summarize key procedures in 3D bioprinting for cartilage repair, and propose strategies for constructing joint organoids using 3D bioprinting. The authors also discuss the challenges of using joint organoids' approaches and perspectives on their future applications, opening opportunities to model joint tissues and response to joint disease treatment.

A Factor-Free Hydrogel with ROS Scavenging and Responsive Degradation for Enhanced Diabetic Bone Healing.

In view of the increased levels of reactive oxygen species (ROS) that disturb the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), the repair of diabetic bone defects remains a great challenge. Herein, a factor-free hydrogel is reported with ROS scavenging and responsive degradation properties for enhanced diabetic bone healing. These hydrogels contain ROS-cleavable thioketal (TK) linkers and ultraviolet (UV)-responsive norbornene (NB) groups conjugated with 8-arm PEG macromers, which are formed via UV crosslinking-mediated gelation. Upon reacting with high levels of ROS in the bone defect microenvironment, ROS-cleavable TK linkers are destroyed, allowing the responsive degradation of hydrogels, which promotes the migration of BMSCs. Moreover, ROS levels are reduced through hydrogel-mediated ROS scavenging to reverse BMSC differentiation from adipogenic to osteogenic phenotype. As such, a favorable microenvironment is created after simultaneous ROS scavenging and hydrogel degradation, leading to the effective repair of bone defects in diabetic mouse models, even without the addition of growth factors. Thus, this study presents a responsive hydrogel platform that regulates ROS scavenging and stromal degradation in bone engineering.

Smart osteoclasts targeted nanomedicine based on amorphous CaCO3 for effective osteoporosis reversal.

BACKGROUND: Osteoporosis is characterized by an imbalance in bone homeostasis, resulting in the excessive dissolution of bone minerals due to the acidified microenvironment mediated by overactive osteoclasts. Oroxylin A (ORO), a natural flavonoid, has shown potential in reversing osteoporosis by inhibiting osteoclast-mediated bone resorption. The limited water solubility and lack of targeting specificity hinder the effective accumulation of Oroxylin A within the pathological environment of osteoporosis. RESULTS: Osteoclasts' microenvironment-responsive nanoparticles are prepared by incorporating Oroxylin A with amorphous calcium carbonate (ACC) and coated with glutamic acid hexapeptide-modified phospholipids, aiming at reinforcing the drug delivery efficiency as well as therapeutic effect. The obtained smart nanoparticles, coined as OAPLG, could instantly neutralize acid and release Oroxylin A in the extracellular microenvironment of osteoclasts. The combination of Oroxylin A and ACC synergistically inhibits osteoclast formation and activity, leading to a significant reversal of systemic bone loss in the ovariectomized mice model. CONCLUSION: The work highlights an intelligent nanoplatform based on ACC for spatiotemporally controlled release of lipophilic drugs, and illustrates prominent therapeutic promise against osteoporosis.

Harnessing Nucleic Acids Nanotechnology for Bone/Cartilage Regeneration.

The effective regeneration of weight-bearing bone defects and critical-sized cartilage defects remains a significant clinical challenge. Traditional treatments such as autologous and allograft bone grafting have not been successful in achieving the desired outcomes, necessitating the need for innovative therapeutic approaches. Nucleic acids have attracted significant attention due to their ability to be designed to form discrete structures and programmed to perform specific functions at the nanoscale. The advantages of nucleic acid nanotechnology offer numerous opportunities for in-cell and in vivo applications, and hold great promise for advancing the field of biomaterials. In this review, the current abilities of nucleic acid nanotechnology to be applied in bone and cartilage regeneration are summarized and insights into the challenges and future directions for the development of this technology are provided.

RANKL from bone marrow adipose lineage cells promotes osteoclast formation and bone loss.

Receptor activator of NF-κB ligand (RANKL) is essential for osteoclast formation and bone remodeling. Nevertheless, the cellular source of RANKL for osteoclastogenesis has not been fully uncovered. Different from peripheral adipose tissue, bone marrow (BM) adipose lineage cells originate from bone marrow mesenchymal stromal cells (BMSCs). Here, we demonstrate that adiponectin promoter-driven Cre expression (AdipoqCre ) can target bone marrow adipose lineage cells. We cross the AdipoqCre mice with ranklfl/fl mice to conditionally delete RANKL from BM adipose lineage cells. Conditional deletion of RANKL increases cancellous bone mass of long bones in mice by reducing the formation of trabecular osteoclasts and inhibiting bone resorption but does not affect cortical bone thickness or resorption of calcified cartilage. AdipoqCre ; ranklfl/fl mice exhibit resistance to estrogen deficiency and rosiglitazone (ROS)-induced trabecular bone loss but show bone loss induced by unloading. BM adipose lineage cells therefore represent an essential source of RANKL for the formation of trabecula osteoclasts and resorption of cancellous bone during remodeling under physiological and pathological conditions. Targeting bone marrow adiposity is a promising way of preventing pathological bone loss.

Cell unit-inspired natural nano-based biomaterials as versatile building blocks for bone/cartilage regeneration.

The regeneration of weight-bearing bone defects and critical-sized cartilage defects remains a significant challenge. A wide range of nano-biomaterials are available for the treatment of bone/cartilage defects. However, their poor compatibility and biodegradability pose challenges to the practical applications of these nano-based biomaterials. Natural biomaterials inspired by the cell units (e.g., nucleic acids and proteins), have gained increasing attention in recent decades due to their versatile functionality, compatibility, biodegradability, and great potential for modification, combination, and hybridization. In the field of bone/cartilage regeneration, natural nano-based biomaterials have presented an unparalleled role in providing optimal cues and microenvironments for cell growth and differentiation. In this review, we systematically summarize the versatile building blocks inspired by the cell unit used as natural nano-based biomaterials in bone/cartilage regeneration, including nucleic acids, proteins, carbohydrates, lipids, and membranes. In addition, the opportunities and challenges of natural nano-based biomaterials for the future use of bone/cartilage regeneration are discussed.

The synergetic effect of a gold nanocluster-calcium phosphate composite: enhanced photoluminescence intensity and superior bioactivity.

Gold nanoclusters (AuNCs) are a unique class of materials that exhibit visible luminescence. Amorphous calcium phosphate (ACP) is a widely used biomaterial for a variety of purposes, such as drug delivery, bone cementing, and implant coatings. In this study, a nanocomposite of AuNCs and ACP is prepared by biomimetic mineralization in a Dulbecco's modified Eagle's medium (DMEM). The strong interaction between AuNCs and Ca2+ ions effectively induces aggregation of AuNCs. The as-formed nanocomposite, AuNCs@ACP, emits significantly enhanced luminescence compared to AuNCs alone. The luminescence enhancement mechanism is investigated using synchrotron X-ray absorption fine structure spectroscopy. In addition, the presence of AuNCs stabilizes ACP and also enhances the biocompatibility of ACP in promoting cell proliferation, and the nanocomposites are promising as nanoprobes for cancer therapy and/or bone tissue engineering.

Diterbutyl phthalate attenuates osteoarthritis in ACLT mice via suppressing ERK/c-fos/NFATc1 pathway, and subsequently inhibiting subchondral osteoclast fusion.

Osteoarthritis (OA) is the most common arthritis with a rapidly increasing prevalence. Disease progression is irreversible, and there is no curative therapy available. During OA onset, abnormal mechanical loading leads to excessive osteoclastogenesis and bone resorption in subchondral bone, causing a rapid subchondral bone turnover, cyst formation, sclerosis, and finally, articular cartilage degeneration. Moreover, osteoclast-mediated angiogenesis and sensory innervation in subchondral bone result in abnormal vascularization and OA pain. The traditional Chinese medicine Panax notoginseng (PN; Sanqi) has long been used in treatment of bone diseases including osteoporosis, bone fracture, and OA. In this study we established two-dimensional/bone marrow mononuclear cell/cell membrane chromatography/time of flight mass spectrometry (2D/BMMC/CMC/TOFMS) technique and discovered that diterbutyl phthalate (DP) was the active constituent in PN inhibiting osteoclastogenesis. Then we explored the therapeutic effect of DP in an OA mouse model with anterior cruciate ligament transaction (ACLT). After ACLT was conducted, the mice received DP (5 mg·kg-1·d-1, ip) for 8 weeks. Whole knee joint tissues of the right limb were harvested at weeks 2, 4, and 8 for analysis. We showed that DP administration impeded overactivated osteoclastogenesis in subchondral bone and ameliorated articular cartilage deterioration. DP administration blunted aberrant H-type vessel formation in subchondral bone marrow and alleviated OA pain assessed in Von Frey test and thermal plantar test. In RANKL-induced RAW264.7 cells in vitro, DP (20 µM) retarded osteoclastogenesis by suppressing osteoclast fusion through inhibition of the ERK/c-fos/NFATc1 pathway. DP treatment also downregulated the expression of dendritic cell-specific transmembrane protein (DC-STAMP) and d2 isoform of the vacuolar (H+) ATPase V0 domain (Atp6v0d2) in the cells. In conclusion, we demonstrate that DP prevents OA progression by inhibiting abnormal osteoclastogenesis and associated angiogenesis and neurogenesis in subchondral bone.

Structure Engineering of Yolk-Shell Magnetic Mesoporous Silica Microspheres with Broccoli-Like Morphology for Efficient Catalysis and Enhanced Cellular Uptake.

Yolk-shell magnetic mesoporous microspheres exhibit potential applications in biomedicine, bioseparation, and catalysis. Most previous reports focus on establishing various interface assembly strategies to construct yolk-shell mesoporous structures, while little work has been done to control their surface topology and study their relevant applications. Herein, a unique kind of broccoli-like yolk-shell magnetic mesoporous silica (YS-BMM) microsphere is fabricated through a surfactant-free kinetic controlled interface assembly strategy. The obtained YS-BMM microspheres possess a well-defined structure consisting of a magnetic core, middle void, mesoporous silica shell with tunable surface roughness, large superparamagnetism (36.4 emu g-1 ), high specific surface area (174 m2 g-1 ), and large mesopores of 10.9 nm. Thanks to these merits and properties, the YS-BMM microspheres are demonstrated to be an ideal support for immobilization of ultrafine Pt nanoparticles (≈3.7 nm) and serve as superior nanocatalysts for hydrogenation of 4-nitrophenol with yield of over 90% and good magnetic recyclability. Furthermore, YS-BMM microspheres show excellent biocompatibility and can be easily phagocytosed by osteoclasts, revealing a potential candidate in sustained drug release in orthopedic disease therapy.

Triptolide prevents bone loss via suppressing osteoclastogenesis through inhibiting PI3K-AKT-NFATc1 pathway.

Bone loss (osteopenia) is a common complication in human solid tumour. In addition, after surgical treatment of gynaecological tumour, osteoporosis often occurs due to the withdrawal of oestrogen. The major characteristic of osteoporosis is the low bone mass with micro-architectural deteriorated bone tissue. And the main cause is the overactivation of osteoclastogenesis, which is one of the most important therapeutic targets. Inflammation could induce the interaction of RANKL/RANK, which is the promoter of osteoclastogenesis. Triptolide is derived from the traditional Chinese herb lei gong teng, presented multiple biological effects, including anti-cancer, anti-inflammation and immunosuppression. We hypothesized that triptolide could inhibits osteoclastogenesis by suppressing inflammation activation. In this study, we confirmed that triptolide could suppress RANKL-induced osteoclastogenesis in bone marrow mononuclear cells (BMMCs) and RAW264.7 cells and inhibited the osteoclast bone resorption functions. PI3K-AKT-NFATc1 pathway is one of the most important downstream pathways of RANKL-induced osteogenesis. The experiments in vitro indicated that triptolide suppresses the activation of PI3K-AKT-NFATc1 pathway and the target point located at the upstream of AKT because both NFATc1 overexpression and AKT phosphorylation could ameliorate the triptolide suppression effects. The expression of MDM2 was elevated, which demonstrated the MDM-p53-induced cell death might contribute to the osteoclastogenesis suppression. Ovariectomy-induced bone loss and inflammation activation were also found to be ameliorated in the experiments in vivo. In summary, the new effect of anti-cancer drug triptolide was demonstrated to be anti-osteoclastogenesis, and we demonstrated triptolide might be a promising therapy for bone loss caused by tumour.

Guaiacol suppresses osteoclastogenesis by blocking interactions of RANK with TRAF6 and C-Src and inhibiting NF-κB, MAPK and AKT pathways.

Angelica sinensis (AS; Dang Gui), a traditional Chinese herb, has for centuries been used for the treatment of bone diseases, including osteoporosis and osteonecrosis. However, the effective ingredient and underlying mechanisms remain elusive. Here, we identified guaiacol as the active component of AS by two-dimensional cell membrane chromatography/C18 column/time-of-flight mass spectrometry (2D CMC/C18 column/TOFMS). Guaiacol suppressed osteoclastogenesis and osteoclast function in bone marrow monocytes (BMMCs) and RAW264.7 cells in vitro in a dose-dependent manner. Co-immunoprecipitation indicated that guaiacol blocked RANK-TRAF6 association and RANK-C-Src association. Moreover, guaiacol prevented phosphorylation of p65, p50, IκB (NF-κB pathway), ERK, JNK, c-fos, p38 (MAPK pathway) and Akt (AKT pathway), and reduced the expression levels of Cathepsin K, CTR, MMP-9 and TRAP. Guaiacol also suppressed the expression of nuclear factor of activated T-cells cytoplasmic 1(NFATc1) and the RANKL-induced Ca2+ oscillation. In vivo, it ameliorated ovariectomy-induced bone loss by suppressing excessive osteoclastogenesis. Taken together, our findings suggest that guaiacol inhibits RANKL-induced osteoclastogenesis by blocking the interactions of RANK with TRAF6 and C-Src, and by suppressing the NF-κB, MAPK and AKT signalling pathways. Therefore, this compound shows therapeutic potential for osteoclastogenesis-related bone diseases, including postmenopausal osteoporosis.

Neobavaisoflavone inhibits osteoclastogenesis through blocking RANKL signalling-mediated TRAF6 and c-Src recruitment and NF-κB, MAPK and Akt pathways.

Psoralea corylifolia (P corylifolia) has been popularly applied in traditional Chinese medicine decoction for treating osteoporosis and promoting fracture healing since centuries ago. However, the bioactive natural components remain unknown. In this study, applying comprehensive two-dimensional cell membrane chromatographic/C18 column/time-of-flight mass spectrometry (2D CMC/C18 column/TOFMS) system, neobavaisoflavone (NBIF), for the first time, was identified for the bioaffinity with RAW 264.7 cells membranes from the extracts of P corylifolia. Here, we revealed that NBIF inhibited RANKL-mediated osteoclastogenesis in bone marrow monocytes (BMMCs) and RAW264.7 cells dose dependently at the early stage. Moreover, NBIF inhibited osteoclasts function demonstrated by actin ring formation assay and pit-formation assay. With regard to the underlying molecular mechanism, co-immunoprecipitation showed that both the interactions of RANK with TRAF6 and with c-Src were disrupted. In addition, NBIF inhibited the phosphorylation of P50, P65, IκB in NF-κB pathway, ERK, JNK, P38 in MAPKs pathway, AKT in Akt pathway, accompanied with a blockade of calcium oscillation and inactivation of nuclear translocation of nuclear factor of activated T cells cytoplasmic 1 (NFATc1). In vivo, NBIF inhibited osteoclastogenesis, promoted osteogenesis and ameliorated bone loss in ovariectomized mice. In summary, P corylifolia-derived NBIF inhibited RANKL-mediated osteoclastogenesis by suppressing the recruitment of TRAF6 and c-Src to RANK, inactivating NF-κB, MAPKs, and Akt signalling pathways and inhibiting calcium oscillation and NFATc1 translocation. NBIF might serve as a promising candidate for the treatment of osteoclast-associated osteopenic diseases.

l-tetrahydropalmatine suppresses osteoclastogenesis in vivo and in vitro via blocking RANK-TRAF6 interactions and inhibiting NF-κB and MAPK pathways.

Bone homeostasis is delicately orchestrated by osteoblasts and osteoclasts. Various pathological bone loss situations result from the overactivated osteoclastogenesis. Receptor activator of nuclear factor κB ligand (RANKL)-activated NF-κB and MAPK pathways is vital for osteoclastogenesis. Here, we for the first time explored the effects of l-tetrahydropalmatine (l-THP), an active alkaloid derived from corydalis, on the formation and function of osteoclasts in vitro and in vivo. In RAW264.7 cells and bone marrow monocytes cells (BMMCs), l-THP inhibited osteoclastic differentiation at the early stage, down-regulated transcription level of osteoclastogenesis-related genes and impaired osteoclasts functions. Mechanically, Western blot showed that l-THP inhibited the phosphorylation of P50, P65, IκB, ERK, JNK and P38, and the electrophoretic mobility shift assay (EMSA) revealed that DNA binding activity of NF-κB was suppressed, ultimately inhibiting the expression of nuclear factor of activated T cells (NFATc1). Besides, Co-immunoprecipitation indicated that l-THP blocked the interactions of RANK and TNF receptor associated factor 6 (TRAF6) at an upstream site. In vivo, l-THP significantly inhibited ovariectomy-induced bone loss and osteoclastogenesis in mice. Collectively, our study demonstrated that l-THP suppressed osteoclastogenesis by blocking RANK-TRAF6 interactions and inhibiting NF-κB and MAPK pathways. l-THP is a promising agent for treating osteoclastogenesis-related diseases such as post-menopausal osteoporosis.

Nanotopographical Cues Mediate Osteogenesis of Stem Cells on Virus Substrates through BMP-2 Intermediate.

Recent studies have demonstrated rapid osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) on substrates with plant virus modified nanotopographical cues as a promising strategy for bone repair; however, the mechanisms remain unclear. We hypothesized that the highly structurally ordered virus coat proteins, responsible for targeting specific cellular components, are critical for the osteogenesis promotion. In this study, hybrid viral gold nanorods were prepared to explore the effects of highly ordered arranged virus coat proteins on osteogenic differentiation of BMSCs. The results herein indicate that it is the nanotopographical cues modified by structurally ordered virus nanoparticles, not the chemical properties of virus surface, that mediate osteogenesis. Bone morphogenetic protein 2 (BMP-2) expression is significantly increased and serves as a modulator that mediates the osteogenic differentiation in response to the viral particle coatings. After BMP-2 is inhibited by Noggin, the osteogenesis promoting effects are significantly compromised, demonstrated by lower alkaline phosphatase activity and calcium sequestration. This study reveals that plant virus modified nanotopographical substrates promote osteogenic differentiation of BMSCs through increasing BMP-2 autocrine. It provides key insights to engineering functional materials for rapid bone repair.

Reversal of Osteoporotic Activity by Endothelial Cell-Secreted Bone Targeting and Biocompatible Exosomes.

Exosomes, also known as extracellular vesicles, are naturally occurring, biocompatible, and bioacive nanoparticles ranging from 40 to 150 nm in diameter. Bone-secreted exosomes play important roles in bone homeostasis, the interruption of which can lead to diseases such as osteoporosis, rheumatoid arthritis, and osteopetrosis. Though the relationship between vascular and bone homeostasis has been recognized recently, the role of vascular endothelial cell (EC)-secreted exosomes (EC-Exos) in bone homeostasis is not well understood. Herein, we found that EC-Exos show more efficient bone targeting than osteoblast-derived exosomes or bone marrow mesenchymal stem cell-derived exosomes. We also found that EC-Exos can be internalized by bone marrow-derived macrophages (BMMs) to alter their morphology. EC-Exos can inhibit osteoclast activity in vitro and inhibit osteoporosis in an ovariectomized mouse model. Sequencing of exosome miRNA revealed that miR-155 was highly expressed in EC-Exos-treated BMMs. The miR-155 level in EC-Exos was much higher than that in BMMs and ECs, indicating that miR-155 was endogenous cargo of EC-derived vesicles. Blockage of BMMs miR-155 levels reversed the suppression by EC-Exos of osteoclast induction, confirming that exosomal miR-155 may have therapeutic potential against osteoporosis. Taken together, our findings suggest that EC-Exos may be utilized as a bone targeting and nontoxic nanomedicine for the treatment of bone resorption disorders.

Shikimic Acid Inhibits Osteoclastogenesis in Vivo and in Vitro by Blocking RANK/TRAF6 Association and Suppressing NF-κB and MAPK Signaling Pathways.

BACKGROUND/AIMS: Bone homeostasis is associated with the balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Unbalanced bone homeostasis as a result of reduced osteogenesis or excessive osteoclastogenesis can lead to disorders such as osteoporosis, Paget's disease, and rheumatoid arthritis. Shikimic acid is a cyclohexanecarboxylic acid, reported to exhibit pharmacological properties including anti-inflammatory and antioxidant activities. However, its effects on bone homeostasis remain unknown. METHODS: First, the in vitro MTT cell viability assay was performed. Tartrate-resistant acid phosphatase (TRAP) and actin ring formation assays, as well as immunofluorescence staining were then performed to evaluate osteoclastogenesis. Potential signaling pathways were characterized by western blotting and verified in overexpression experiments. Related factors were examined by western blotting, reverse transcription polymerase chain reaction, electrophoretic mobility shift assay, and co-immunoprecipitation. Ovariectomized mice were used for the in vivo study. RESULTS: TRAP staining showed that shikimic acid significantly inhibited osteoclastogenesis and pit resorption in bone marrow monocytes and RAW264.7 cells, and actin ring formation assays showed that shikimic acid suppressed the bone resorption function of osteoclasts. Furthermore, shikimic acid inhibited the receptor activator of nuclear factor-κB RANK/tumor necrosis factor receptor-associated factor 6 (TRAF6) association, suppressed nuclear factor-κB and mitogen-activated protein kinase signaling pathways, and downregulated nuclear factor of activated T-cell cytoplasmic 1. The expression of osteoclastogenesis biomarkers, including TRAF6, calcitonin receptor, TRAP, cathepsin K, and matrix metalloproteinase-9, was inhibited. In vivo, shikimic acid also significantly ameliorated bone loss and prevented osteoclastogenesis in ovariectomized mice. CONCLUSION: Shikimic acid inhibited osteoclastogenesis and osteoclast function by blocking RANK ligand-induced recruitment of TRAF6, as well as downstream signaling pathways in vitro. Shikimic acid also reduced ovariectomy-induced osteoclastogenesis and bone loss in vivo.

Inhalation of Hydrogen of Different Concentrations Ameliorates Spinal Cord Injury in Mice by Protecting Spinal Cord Neurons from Apoptosis, Oxidative Injury and Mitochondrial Structure Damages.

BACKGROUND/AIMS: Hydrogen selectively neutralizes reactive oxygen species (ROS) and ameliorates various ROS-induced injuries. Spinal cord injury (SCI) is a serious injury to the central nervous system, and secondary SCI is closely related to excessive ROS generation. We hypothesized that hydrogen inhalation ameliorates SCI, and the mechanism of action may be related to the protective effects of hydrogen against oxidative stress, apoptosis, and mitochondrial damage. METHODS: Mechanically injured spinal cord neurons were incubated with different concentrations of hydrogen in vitro. Immunofluorescence staining and transmission electron microscopy were used to confirm the protective effects of hydrogen. ROS and related proteins were detected with dihydroethidium fluorescence staining, enzyme-linked immunosorbent assays, and western blotting. Terminal deoxynucleotidyl transferase dUTP nick end labeling assays, flow cytometry, and western blotting were used to detect neuronal apoptosis. ATP concentrations, Janus Green B staining, and mitochondrial permeability transition pore (mPTP) status were assessed to investigate mitochondrial damage. RNA sequencing was performed to screen potential target genes of hydrogen application. Hydrogen was administered to mice after spinal cord contusion injury was established for 42 days. The Basso Mouse Scale (BMS) and footprint analyses were used to assess locomotor functions, and immunofluorescence staining of the injured spinal cord segments was performed to detect oxidative stress status. RESULTS: Spinal cord neurons were preserved by hydrogen administration after mechanical injury in a dose-dependent manner. ROS generation, oxidative stress injury-related markers, and the number of apoptotic neurons were significantly reduced after hydrogen treatment. The ATP production and mPTP function in injured neurons were preserved by hydrogen incubation. The expression levels of Cox8b, Cox6a2, Cox7a1, Hspb7, and Atp2a1 were inhibited by hydrogen treatment. BMS scores and the footprint assessment of mice with SCI were improved by hydrogen inhalation. CONCLUSIONS: Hydrogen inhalation (75%) ameliorated SCI in vivo and attenuated neuronal mechanical injuries in vitro, and its protective effect on spinal cord neurons was exerted in a dose-dependent manner. The underlying mechanisms included reducing ROS generation and oxidative stress, inhibiting neuronal apoptosis, and restoring mitochondrial construction and function. Cox8b, Cox6a2, Cox7a1, Hspb7, and Atp2a1 were identified as potential target genes of hydrogen treatment.

Matrine prevents bone loss in ovariectomized mice by inhibiting RANKL-induced osteoclastogenesis.

Osteoporosis is a metabolic bone disease characterized by decreased bone density and strength due to excessive loss of bone protein and mineral content. The imbalance between osteogenesis by osteoblasts and osteoclastogenesis by osteoclasts contributes to the pathogenesis of postmenopausal osteoporosis. Estrogen withdrawal leads to increased levels of proinflammatory cytokines. Overactivated osteoclasts by inflammation play a vital role in the imbalance. Matrine is an alkaloid found in plants from the Sophora genus with various pharmacological effects, including anti-inflammatory activity. Here we demonstrate that matrine significantly prevented ovariectomy-induced bone loss and inhibited osteoclastogenesis in vivo with decreased serum levels of TRAcp5b, TNF-α, and IL-6. In vitro matrine significantly inhibited osteoclast differentiation induced by receptor activator for NF-κB ligand (RANKL) and M-CSF in bone marrow monocytes and RAW264.7 cells as demonstrated by tartrate-resistant acid phosphatase (TRAP) staining and actin-ring formation as well as bone resorption through pit formation assays. For molecular mechanisms, matrine abrogated RANKL-induced activation of NF-κB, AKT, and MAPK pathways and suppressed osteoclastogenesis-related marker expression, including matrix metalloproteinase 9, NFATc1, TRAP, C-Src, and cathepsin K. Our study demonstrates that matrine inhibits osteoclastogenesis through modulation of multiple pathways and that matrine is a promising agent in the treatment of osteoclast-related diseases such as osteoporosis.-Chen, X., Zhi, X., Pan, P., Cui, J., Cao, L., Weng, W., Zhou, Q., Wang, L., Zhai, X. Zhao, Q., Hu, H., Huang, B., Su, J. Matrine prevents bone loss in ovariectomized mice by inhibiting RANKL-induced osteoclastogenesis.

Lithium doped silica nanospheres/poly(dopamine) composite coating on polyetheretherketone to stimulate cell responses, improve bone formation and osseointegration.

Osseointegration is crucial for early fixation as well as long-term success of orthopedic implants. Bioactive composite containing lithium doping silica nanospheres (LSNs) and poly(dopamine) (PDA) were coated on polyetheretherketone (PK) surface (LPPK), and effects of the LSNs/PDA composite (LPC) coating on the biological properties of LPPK were assessed both in vitro and in vivo. Results showed that LPPK with improved bioactivity remarkably promoted apatite mineralization in simulated body fluid (SBF) compared with PDA coated on PK (PPK) and PK. Moreover, the LPPK remarkably stimulated rat bone marrow stromal cells (rBMSCs) responses compared with PPK and PK. Furthermore, the LPPK significantly promoted bone tissues responses in vivo compared with PPK and PK. It could be suggested that the improvements of cells and bone tissues responses were attributed to the surface characteristics of the bioactive LPC coating on LPPK. The LPPK would be a great candidate for orthopedic and dental applications.

Plasmolysis-Inspired Nanoengineering of Functional Yolk-Shell Microspheres with Magnetic Core and Mesoporous Silica Shell.

Yolk-shell nanomaterials with a rattle-like structure have been considered ideal carriers and nanoreactors. Traditional methods to constructing yolk-shell nanostructures mainly rely on multistep sacrificial template strategy. In this study, a facile and effective plasmolysis-inspired nanoengineering strategy is developed to controllably fabricate yolk-shell magnetic mesoporous silica microspheres via the swelling-shrinkage of resorcinol-formaldehyde (RF) upon soaking in or removal of n-hexane. Using Fe3O4@RF microspheres as seeds, surfactant-silica mesostructured composite is deposited on the swelled seeds through the multicomponent interface coassembly, followed by solvent extraction to remove surfactant and simultaneously induce shrinkage of RF shell. The obtained yolk-shell microspheres (Fe3O4@RF@void@mSiO2) possess a high magnetization of 40.3 emu/g, high surface area (439 m2/g), radially aligned mesopores (5.4 nm) in the outer shell, tunable middle hollow space (472-638 nm in diameter), and a superparamagnetic core. This simple method allows a simultaneous encapsulation of Au nanoparticles into the hollow space during synthesis, and it leads to spherical Fe3O4@RF@void-Au@mSiO2 magnetic nanocatalysts, which show excellent catalysis efficiency for hydrogenation of 4-nitrophenol by NaBH4 with a high conversion rate (98%) and magnetic recycling stability.