A facile and smart strategy to enhance bone regeneration with efficient vitamin D3 delivery through sterosome technology.

The spontaneous healing of critical-sized bone defects is often limited, posing an increased risk of complications and suboptimal outcomes. Osteogenesis, a complex process central to bone formation, relies significantly on the pivotal role of osteoblasts. Despite the well-established osteogenic properties of vitamin D3 (VD3), its lipophilic nature confines administration to oral or muscle injection routes. Therefore, a strategic therapeutic approach involves designing a multifunctional carrier to enhance efficacy, potentially incorporating it into the delivery system. Here, we introduce an innovative sterosome-based delivery system, utilizing palmitic acid (PA) and VD3, aimed at promoting osteogenic differentiation and facilitating post-defect bone regeneration. The delivery system exhibited robust physical characteristics, including excellent stability, loading efficiency, sustained drug release and high cellular uptake efficiency. Furthermore, comprehensive investigations demonstrated outstanding biocompatibility and osteogenic potential in both 2D and 3D in vitro settings. A critical-sized calvarial defect model in mice recapitulated the notable osteogenic effects of the sterosomes in vivo. Collectively, our research proposes a clinically applicable strategy for bone healing, leveraging PA/VD3 sterosomes as an efficient carrier to deliver VD3 and enhance bone regenerative effects.

Polymerizable rotaxane of cucurbituril protecting dopamine based adhesive hydrogels.

The catechol moiety found within mussel proteins plays a pivotal role in enhancing their adhesive properties. Nonetheless, catechol compounds, such as dopamine (DOP) derivatives, are susceptible to oxidation, leading to the formation of quinone. This oxidation process poses a significant challenge in the development of DOP-based hydrogels, hampering their adhesion capabilities and hindering polymerization. To protect DOP moieties from oxidation, DOP and N-(3-aminopropyl)methacrylamide (AMA) moieties were grafted onto the side groups of biocompatible poly(glutamic acid) (PGA). Subsequently, the DOP unit, serving as a second guest, would be captured by a polymerizable rotaxane of cucurbituril (CB[n]), in which the host molecule CB[8] complexed with the first guest, polymerizable methyl viologen (MV), forming a protective function and dynamic cross-linking. Upon exposure to light curing, a composite network emerged through the synergy of covalent cross-linking and supramolecular host-guest complexation of DOP with CB[8]. The generated complexation between DOP and CB[8] could protect the DOP moieties, resulting in photocured hydrogels with exceptional adhesive strength and remarkable tensile capabilities. Moreover, 3D printing technology was used to create various models with these DOP-based hydrogels, demonstrating their promising applications in future.

Choosing the right animal model for osteomyelitis research: Considerations and challenges.

Osteomyelitis is a debilitating bone disorder characterized by an inflammatory process involving the bone marrow, bone cortex, periosteum, and surrounding soft tissue, which can ultimately result in bone destruction. The etiology of osteomyelitis can be infectious, caused by various microorganisms, or noninfectious, such as chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO). Researchers have turned to animal models to study the pathophysiology of osteomyelitis. However, selecting an appropriate animal model that accurately recapitulates the human pathology of osteomyelitis while controlling for multiple variables that influence different clinical presentations remains a significant challenge. In this review, we present an overview of various animal models used in osteomyelitis research, including rodent, rabbit, avian/chicken, porcine, minipig, canine, sheep, and goat models. We discuss the characteristics of each animal model and the corresponding clinical scenarios that can provide a basic rationale for experimental selection. This review highlights the importance of selecting an appropriate animal model for osteomyelitis research to improve the accuracy of the results and facilitate the development of novel treatment and management strategies.

Exploring the translational potential of PLGA nanoparticles for intra-articular rapamycin delivery in osteoarthritis therapy.

Osteoarthritis (OA) is a prevalent joint disease that affects all the tissues within the joint and currently lacks disease-modifying treatments in clinical practice. Despite the potential of rapamycin for OA disease alleviation, its clinical application is hindered by the challenge of achieving therapeutic concentrations, which necessitates multiple injections per week. To address this issue, rapamycin was loaded into poly(lactic-co-glycolic acid) nanoparticles (RNPs), which are nontoxic, have a high encapsulation efficiency and exhibit sustained release properties for OA treatment. The RNPs were found to promote chondrogenic differentiation of ATDC5 cells and prevent senescence caused by oxidative stress in primary mouse articular chondrocytes. Moreover, RNPs were capable to alleviate metabolism homeostatic imbalance of primary mouse articular chondrocytes in both monolayer and 3D cultures under inflammatory or oxidative stress. In the mouse destabilization of the medial meniscus (DMM) model, intra-articular injection of RNPs effectively mitigated joint cartilage destruction, osteophyte formation, chondrocytes hypertrophy, synovial inflammation, and pain. Our study demonstrates the feasibility of using RNPs as a potential clinically translational therapy to prevent the progression of post-traumatic OA.

Main-Chain Cationic Bile Acid Polymers Mimicking Facially Amphiphilic Antimicrobial Peptides.

Antibiotic-resistant bacterial infections have led to an increased demand for antibacterial agents that do not contribute to antimicrobial resistance. Antimicrobial peptides (AMPs) with the facially amphiphilic structures have demonstrated remarkable effectiveness, including the ability to suppress antibiotic resistance during bacterial treatment. Herein, inspired by the facially amphiphilic structure of AMPs, the facially amphiphilic skeletons of bile acids (BAs) are utilized as building blocks to create a main-chain cationic bile acid polymer (MCBAP) with macromolecular facial amphiphilicity via polycondensation and a subsequent quaternization. The optimal MCBAP displays an effective activity against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli, fast killing efficacy, superior bactericidal stability in vitro, and potent anti-infectious performance in vivo using the MRSA-infected wound model. MCBAP shows the low possibility to develop drug-resistant bacteria after repeated exposure, which may ascribe to the macromolecular facial amphiphilicity promoting bacterial membrane disruption and the generation of reactive oxygen species. The easy synthesis and low cost of MCBAP, the superior antimicrobial performance, and the therapeutic potential in treating MRSA infection altogether demonstrate that BAs are a promising group of building blocks to mimic the facially amphiphilic structure of AMPs in treating MRSA infection and alleviating antibiotic resistance.

Phosphoproteomics Reveal New Candidates in Abnormal Spermatogenesis of Pseudomales in Cynoglossus semilaevis.

Phosphorylation is a post-translational modification that contributes to versatile protein functions in spermatogenesis, and the variations they generate usually results in abnormal spermatogenesis or sperm dysfunction. The sex-reversal phenomenon exists in Chinese tongue sole under certain conditions such that individuals with a ZW genotype can acquire a male phenotype and are thus called pseudomales. Pseudomale tongue sole can reach sexual maturity but produce only Z-type sperm, and the Z sperm carries paternal epigenetic information. Whether phosphorylation plays a role in the sperm abnormality of pseudomales is unknown. In this study, a phosphoproteomic analysis was performed to compare protein phosphorylation profiles between pseudomale and male testes. Altogether, we identified 14,253 phosphopeptides matching with 4843 proteins, with 1329 differentially phosphorylated peptides corresponding to 1045 differentially phosphorylated proteins (DPPs). Phosphorylation at 781 sites was upregulated and at 548 sites was downregulated. Four motifs were identified among differentially phosphorylated peptides, which were "SP", "SD", "RxxS", and "TP". Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses suggested that the cell cycle and DNA/RNA processing were significantly enriched with the genes encoding DPPs. To analyze DPP function in depth, a protein-protein interaction network was constructed, and Ran-binding protein 2 was found to play a central role in spermatogenesis by regulating several processes such as the cell cycle, eukaryotic translation, ubiquitination, and minichromosome maintenance. In kinase-associated network analyses, two "mitogen-activated protein kinase (Mapk)-centered" clusters were identified that may account for abnormal spermatogenesis in pseudomales. One cluster was centered on Mapk6, which predominantly regulated the cell cycle by interacting with several cyclin-dependent kinases, and the other was centered on the "testis-expressed kinase 1-like (Tesk1l)/Pim1l-Mapk4l- testis-expressed 14 (Tex14)" kinase cascade, which might contribute to spermatogenesis by regulating ß-catenin. Taken together, these data suggested the new candidates involved in pseudomale sperm abnormalities and provided clues to discover the phosphorylated regulatory mechanism underlying tongue sole spermatogenesis.

Hierarchical and Orderly Surface Conductive Networks in Yolk-Shell Fe3 O4 @C@Co/N-Doped C Microspheres for Enhanced Microwave Absorption.

Constructing the adjustable surface conductive networks is an innovation that can achieve a balance between enhanced attenuation and impedance mismatch according to the microwave absorption mechanism. However, the traditional design strategies remain significant challenges in terms of rational selection and controlled growth of conductive components. Herein, a hierarchical construction strategy and quantitative construction technique are employed to introduce conductive metal-organic frameworks (MOFs) derivatives in the classic yolk-shell structure composed of electromagnetic components and the cavity for remarkable optimized performance. Specifically, the surface conductive networks obtained by carbonized ZIF-67 quantitative construction, together with the Fe3 O4 magnetic core and dielectric carbon layer linked by the cavity, achieve the cooperative enhancement of impedance matching optimization and synergistic attenuation in the Fe3 O4 @C@Co/N-Doped C (FCCNC) absorber. This interesting design is further verified by experimental results and simulation calculations. The products FCCNC-2 yield a distinguished minimum reflection loss of -66.39 dB and an exceptional effective absorption bandwidth of 6.49 GHz, indicating that moderate conduction excited via hierarchical and quantitative design can maximize the absorption capability. Furthermore, the proposed versatile methodology of surface assembly paves a new avenue to maximize beneficial conduction effect and manipulate microwave attenuation in MOFs derivatives.

Inhalable GSH-Triggered Nanoparticles to Treat Commensal Bacterial Infection in In Situ Lung Tumors.

Bacterial infection has been considered one of the primary reasons for low survival rate of lung cancer patients. Herein, we demonstrated that a kind of mesoporous silica nanoparticles loaded with anticancer drug doxorubicin (DOX) and antimicrobial peptide HHC36 (AMP) (MSN@DOX-AMP) can kill both commensal bacteria and tumor cells under GSH-triggering, modulating the immunosuppressive tumor microenvironment, significantly treating commensal bacterial infection, and eliminating in situ lung tumors in a commensal model. Meanwhile, MSN@DOX-AMP encapsulated DOX and AMP highly efficiently via a combined strategy of physical adsorption and click chemistry and exhibited excellent hemocompatibility and biocompatibility. Importantly, MSN@DOX-AMP could be inhaled and accumulate in lung by a needle-free nebulization, achieving a better therapeutic effect. This system is expected to serve as a straightforward platform to treat commensal bacterial infections in tumors and promote the translation of such inhaled GSH-triggered MSN@DOX-AMP to clinical treatments of lung cancer.

Exosome Release Delays Senescence by Disposing of Obsolete Biomolecules.

Accumulation of obsolete biomolecules can accelerate cell senescence and organism aging. The two efficient intracellular systems, namely the ubiquitin-proteasome system and the autophagy-lysosome system, play important roles in dealing with cellular wastes. However, how multicellular organisms orchestrate the processing of obsolete molecules and delay aging remains unclear. Herein, it is shown that prevention of exosome release by GW4869 or Rab27a-/- accelerated senescence in various cells and mice, while stimulating exosome release by nutrient restriction delays aging. Interestingly, exosomes isolate from serum-deprived cells or diet-restricted human plasma, enriched with garbage biomolecules, including misfolded proteins, oxidized lipids, and proteins. These cellular wastes can be englobed by macrophages, eventually, for disintegration in vivo. Inhibition of nutrient-sensing mTORC1 signaling increases exosome release and delays senescence, while constitutive activation of mTORC1 reduces exosome secretion and exacerbates senescence in vitro and in mice. Notably, inhibition of exosome release attenuates nutrient restriction- or rapamycin-delayed senescence, supporting a key role for exosome secretion in this process. This study reveals a potential mechanism by which stimulated exosome release delays aging in multicellular organisms, by orchestrating the harmful biomolecules disposal via exosomes and macrophages.

Intrinsic antibacterial and osteoinductive sterosomes promote infected bone healing.

Open fractures and internal fixation implants are often accompanied by bacterial infection, leading to osteomyelitis, characterized by intractable bone infection and sequestrum formation, and can result in lifelong disability or fatal sepsis. As common clinical treatment strategies, high-dose antibiotic application and autologous bone transplantation face the risk of recurrence and donor site injury. Herein, we designed and prepared a novel drug delivery system by rational selection of the antibacterial single-chain amphiphile (cetylpyridinium chloride, CPC) and osteoinductive sterol (20S-hydroxycholesterol, Oxy) to formulate CPC/Oxy sterosomes. We demonstrate their excellent biocompatibility and antibacterial ability through 2D and 3D settings in vitro. In addition, the osteogenic differentiation of bone marrow mesenchymal stem cells was investigated in cell monolayers and a hydrogel environment. Moreover, a rat infected critical-sized calvarial defect model was employed to illustrate the effects of antibacterial and osteogenic CPC/Oxy sterosomes in vivo. Our results showed that CPC/Oxy sterosomes not only exterminated bacterial infections, but also enhanced calvarial healing without additional antibiotics, bone formation promoters or exogenous cells. This research provides a promising and effective multifunctional sterosomal platform for the treatment of infected bone defects, with the potential to be combined with therapeutic genes, and small molecule drugs.

Evaluation of the transdentinal capability of the intrinsic antibacterial cetylpyridinium chloride/cholesterol sterosomes in vitro and in vivo.

AIM: Dentinal tubules serve as disease-causing channels for infiltration and penetration of bacteria and their by-products; which are regarded as the major driver of pathogenesis in pulpal inflammation and infection. In this study, we aimed to evaluate the transdentinal potential of nanoscale cetylpyridinium chloride/cholesterol (CPC/Chol) sterosomes, which are a recently developed type of cationic non-phospholipid liposomal nanocarrier; as well as their intrinsic and universal antibacterial activity. METHODOLOGY: Cetylpyridinium chloride/cholesterol sterosomes were formulated, with a hydrodynamic diameter of 134 ± 4 nm, a low polydisperse index of 0.161 ± 0.007, and a positive zeta potential of 41 ± 3 mV at pH 7.4. Transdentinal diffusion ability of sterosomes was evaluated using human dentine blocks in vitro, and Wistar rat molar teeth in vivo. The intrinsic antibacterial activities of CPC/Chol sterosomes against Enterococcus faecalis, Streptococcus mutans, Fusobacterium nucleatum, and Porphyromonas gingivalis were further examined. RESULTS: Cetylpyridinium chloride/cholesterol sterosomes successfully penetrated through the dentinal tubules, and diffused into the pulp, which could be internalized by dental pulp cells with a high efficiency. In addition, they exhibited substantial levels of intrinsic antibacterial activity against these Gram-positive and Gram-negative endodontic bacteria and their biofilms. CONCLUSIONS: Given its high penetration and diffusion ability through the dentine and pulp, great potential for multi-drug delivery, and distinct intrinsic antibacterial activity; sterosome-based nanocarriers might serve as a promising therapeutic strategy aimed at targeting various specific pathways associated with pulpal diseases. This will help determine and characterize the most appropriate prophylactic and therapeutic targets for early intervention in our future dentistry practice.

Induced Crystallization-Controllable Nanoarchitectonics of 3D-Ordered Hierarchical Macroporous Co@N-Doped Carbon Frameworks for Enhanced Microwave Absorption.

The construction of ordered hierarchical porous structures in metal-organic frameworks (MOFs) and their derivatives is highly promising to meet the low-density and high-performance demands of microwave absorption materials. However, traditional methods based on sacrificial templates or corrosive agents inevitably suffer from the collapse of the microporous framework and the accumulation of nanoparticles during the carbonization transformation, resulting in the deteriorating impedance match, which greatly limits the incident and attenuation of microwaves. Herein, an induced crystallization and controllable nanoarchitectonics strategy is employed to replace traditional growing-etching methods and successfully synthesize carbonized 3D-ordered macroporous Co@N-doped carbon (3DOM Co@NDC) based on the 3D-ordered template. The obtained 3D-ordered macroporous structure ensures the stable growth of hybrid carbon frameworks and CoC nanoparticles without collapse, preserves abundant interfaces for both the incident and attenuation performance, so as to significantly improve the impedance matching and absorption properties compared to conventional MOFs derivatives. The minimum reflection loss of 3DOM Co@NDC is -57.36 dB at the thickness of 1.9 mm, and the effective bandwidth is 7.36 GHz at 1.6 mm. Moreover, the innovative strategy to prepare 3D-ordered hierarchical macroporous structures opens up a new avenue for advanced MOFs-derived absorbers with excellent performance.

Transcriptomic Analysis Revealed Candidate Genes Involved in Pseudomale Sperm Abnormalities in Chinese Tongue Sole (Cynoglossus semilaevis).

Chinese tongue sole (Cynoglossus semilaevis) has a ZZ/ZW sex determination system, but the genotypic female (ZW) can be sex-reversed into phenotypic males, namely, pseudomales. Pseudomale fish can produce only Z-type sperm but not W sperm. However, the molecular mechanism is unclear. To screen the key genes involved in pseudomale sperm abnormalities, we analysed the transcriptomic profiles of pseudomale and male sperm. In comparison to male sperm, 592 differentially expressed genes (DEGs) were identified in pseudomale sperm, including 499 upregulated and 93 downregulated genes. KEGG analysis indicated that the FoxO signalling pathway, especially the foxo3a and foxo6-like genes, may play an important role in spermatogenesis. The DEGs were mainly distributed on sex chromosomes, with 158 downregulated genes on the Z chromosome and 41 upregulated genes on the W chromosome. A specific area (14-15 M) on the Z chromosome was identified, which enriched eight DEGs inside the ~1 M region. In addition, there were five gene alleles on the sex chromosomes, which showed the opposite transcription pattern (upregulated for the W allele, downregulated for the Z allele). This study has provided valuable data for screening candidate genes involved in the pseudomale sperm abnormality.

Potential Involvement of ewsr1-w Gene in Ovarian Development of Chinese Tongue Sole, Cynoglossus semilaevis.

Ewsr1 encodes a protein that acts as a multifunctional molecule in a variety of cellular processes. The full-length of Cs-ewsr1-w and Cs-ewsr1-z were cloned in Chinese tongue sole (Cynoglossus semilaevis). The open reading frame (ORF) of Cs-ewsr1-w was 1,767 bp that encoded 589 amino acids, while Cs-ewsr1-z was 1,794 bp that encoded 598 amino acids. Real-time PCR assays showed that Cs-ewsr1-w exhibited significant female-biased expression and could be hardly detected in male. It has the most abundant expression in ovaries among eight healthy tissues. Its expression in ovary increased gradually from 90 d to 3 y with C. semilaevis ovarian development and reached the peak at 3 y. After Cs-ewsr1-w knockdown with siRNA interference, several genes related to gonadal development including foxl2, sox9b and pou5f1 were down-regulated in ovarian cell line, suggesting the possible participation of Cs-ewsr1-w in C. semilaevis ovarian development. The dual-luciferase reporter assay revealed that the -733/-154 bp Cs-ewsr1-w promoter fragment exhibited strong transcription activity human embryonic kidney (HEK) 293T cell line. The mutation of a MAF BZIP Transcription Factor K (Mafk) binding site located in this fragment suggested that transcription factor Mafk might play an important role in Cs-ewsr1-w basal transcription. Our results will provide clues on the gene expression level, transcriptional regulation and knock-down effect of ewsr1 gene during ovarian development in teleost.

Identification and Expression Pattern of cyp26b1 Gene in Gonad of the Chinese Tongue Sole (Cynoglossus semilaevis).

As an RA-metabolizing enzyme, cyp26b1 has a substantial impact on RA-signaling pathways. The cyp26b1 gene from the Chinese tongue sole was cloned and identified in this investigation. The cyp26b1 ORF was 1536 bp in length and encoded a 512 amino acid protein. A quantitative real-time PCR (qPCR) indicated that the cyp26b1 expression is no significant sexual dimorphism in the gonads at the 80 days post-hatching (dph) stages. After 4 months post-hatching (mph), the expression of cyp26b1 showed sexual dimorphism and lower level of expression in the ovaries than in the testes. An in situ hybridization demonstrated that cyp26b1 mRNA was primarily located in the testis. Interestingly, the cyp26b1 mRNA probe was also detected in the ovaries. These results suggested that cyp26b1 participates in the sex-differentiation and gonadal development of the Chinese tongue sole.

Polydatin activates the Nrf2/HO-1 signaling pathway to protect cisplatin-induced hearing loss in guinea pigs.

Irreversible sensorineural hearing loss is one of the most common side effects after cisplatin treatment. Prevention and reversal of hearing loss caused by cisplatin are of great importance for cancer patients, especially children. Oxidative stress is an important cause of hearing loss resulted from cisplatin, unfortunately, there is no drug yet available that can completely prevent and reverse the ototoxicity from cisplatin. Polydatin (PD) possesses excellent antioxidant and anti-inflammatory effects, however, its role in the cisplatin-induced hearing loss has not been investigated. Herein, we have explored the preventive and therapeutic effects of PD on cisplatin-induced hearing loss and the possible underlying mechanisms. In the in vivo setting with guinea pigs, we have demonstrated that PD can reduce the threshold shift of auditory brainstem response (ABR) caused by cisplatin, promote the nuclear translocation of Nuclear factor erythroid-2 related factor 2 (Nrf2), increase the expression of Nrf2 and heme oxygenase-1 (HO-1), and thus reduce the loss of outer hair cells (OHCs). PD can ameliorate cisplatin-induced hearing loss through activating the Nrf2/HO-1 signaling pathway. This study provides a potential strategy for preventing and improving hearing loss resulted from cisplatin treatment in clinics.

Morphology-Controlled Fabrication Strategy of Hollow Mesoporous Carbon Spheres@f-Fe2O3 for Microwave Absorption and Infrared Stealth.

The design and development of radar--infrared compatible stealth materials are challenging in the field of broadband absorption due to the contradiction of stealth requirements and mechanisms in different frequency bands. However, hollow structures show great promise for multispectral stealth because they can lengthen the attenuation path of electromagnetic waves (EMWs) for microwave absorption, interrupt the continuity of heat-transport channels, and lower the thermal conductivity to realize infrared stealth. Here, a new morphological fabrication strategy has been developed to efficiently prepare compatible stealth nanomaterials. In a specific hydrothermal process, the confined growth of flake α-Fe2O3 (f-Fe2O3) outside of hollow mesoporous carbon spheres (HMCS) is achieved using NH3·H2O as a shape-controlled reagent. The introduction of f-Fe2O3 helps to lower infrared emissivity and improve high-frequency impedance matching, which depends on the stable dielectric property of the specific flake shape. Moreover, the size of f-Fe2O3 can be regulated by changing the constituent proportion in the hydrothermal suspension to obtain excellent performance. The minimum reflection loss (RL) of the HMCS@f-Fe2O3-6 composite is -34.16 dB at 2.4 mm, and the effective absorption bandwidth (EAB) reaches 4.8 GHz. Furthermore, the lowest emissivities of the HMCS@f-Fe2O3-6-20 wt %/polyetherimide (PEI) film in the 3-5 and 8-14 µm infrared wavebands are 0.212 and 0.508, respectively. These discoveries may pave the way for the development of radar-infrared compatible stealth materials from the perspective of microstructural design.

Epigenetic Regulation of NGF-Mediated Osteogenic Differentiation in Human Dental Mesenchymal Stem Cells.

Nerve growth factor (NGF) is the best-characterized neurotrophin and is primarily recognized for its key role in the embryonic development of the nervous system and neuronal cell survival/differentiation. Recently, unexpected actions of NGF in bone regeneration have emerged as NGF is able to enhance the osteogenic differentiation of mesenchymal stem cells. However, little is known regarding how NGF signaling regulates osteogenic differentiation through epigenetic mechanisms. In this study, using human dental mesenchymal stem cells (DMSCs), we demonstrated that NGF mediates osteogenic differentiation through p75NTR, a low-affinity NGF receptor. P75NTR-mediated NGF signaling activates the JNK cascade and the expression of KDM4B, an activating histone demethylase, by removing repressive H3K9me3 epigenetic marks. Mechanistically, NGF-activated c-Jun binds to the KDM4B promoter region and directly upregulates KDM4B expression. Subsequently, KDM4B directly and epigenetically activates DLX5, a master osteogenic gene, by demethylating H3K9me3 marks. Furthermore, we revealed that KDM4B and c-Jun from the JNK signaling pathway work in concert to regulate NGF-mediated osteogenic differentiation through simultaneous recruitment to the promoter region of DLX5. We identified KDM4B as a key epigenetic regulator during the NGF-mediated osteogenesis both in vitro and in vivo using the calvarial defect regeneration mouse model. In conclusion, our study thoroughly elucidated the molecular and epigenetic mechanisms during NGF-mediated osteogenesis.

hUC-MSC-mediated recovery of subacute spinal cord injury through enhancing the pivotal subunits ß3 and γ2 of the GABAA receptor.

Rationale: Spinal cord injury (SCI) remains an incurable neurological disorder leading to permanent and profound neurologic deficits and disabilities. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are particularly appealing in SCI treatment to curtail damage, restore homeostasis and possible neural relay. However, the detailed mechanisms underlying hUC-MSC-mediated functional recovery of SCI have not been fully elucidated. The purpose of our current study is to identify novel therapeutic targets and depict the molecular mechanisms underlying the hUC-MSC-mediated recovery of subacute SCI. Methods: Adult female rats suffering from subacute incomplete thoracic SCI were treated with intrathecal transplantation of hUC-MSCs. The beneficial effects of hUC-MSCs on SCI repair were evaluated by a series of behavioral analyses, motor evoked potentials (MEPs) recording of hindlimb and immunohistochemistry. We carried out extensive transcriptome comparative analyses of spinal cord tissues at the lesion site from the subacute phase of SCI (sub-SCI) either treated without (+PBS) or with hUC-MSCs (+MSC) at 0 (sub-SCI), 1, 2, and 4 weeks post-transplantation (wpt), as well as normal spinal cord segments of intact/sham rats (Intact). Adeno-associated virus (AAV)-mediated neuron-specific expression system was employed to functionally screen specific γ-aminobutyric acid type A receptor (GABAAR) subunits promoting the functional recovery of SCI in vivo. The mature cortical axon scrape assay and transplantation of genetically modified MSCs with either overexpression or knockdown of brain-derived neurotrophic factor (BDNF) were employed to demonstrate that hUC-MSCs ameliorated the reduction of GABAAR subunits in the injured spinal cord via BDNF secretion in vitro and in vivo, respectively. Results: Comparative transcriptome analysis revealed the GABAergic synapse pathway is significantly enriched as a main target of hUC-MSC-activated genes in the injured spinal cord. Functional screening of the primary GABAAR subunits uncovered that Gabrb3 and Garbg2 harbored the motor and electrophysiological recovery-promoting competence. Moreover, targeting either of the two pivotal subunits ß3 or γ2 in combination with/without the K+/Cl- cotransporter 2 (KCC2) reinforced the therapeutic effects. Mechanistically, BDNF secreted by hUC-MSCs contributed to the upregulation of GABAAR subunits (ß3 & γ2) and KCC2 in the injured neurons. Conclusions: Our study identifies a novel mode for hUC-MSC-mediated locomotor recovery of SCI through synergistic upregulation of GABAAR ß3 and γ2 along with KCC2 by BDNF secretion, indicating the significance of restoring the excitation/inhibition balance in the injured neurons for the reestablishment of neuronal circuits. This study also provides a potential combinatorial approach by targeting the pivotal subunit ß3 or γ2 and KCC2, opening up possibilities for efficacious drug design.

Local delivery of a CXCR3 antagonist decreases the progression of bone resorption induced by LPS injection in a murine model.

OBJECTIVES: This experimental study was carried out to investigate the effects of locally delivered nanoparticles (AMG-487 NP) containing a CXCR3 antagonist in inhibiting the progression of LPS-induced inflammation, osteoclastic activity, and bone resorption on a murine model. MATERIALS AND METHODS: Thirty, 7-week-old C57BL/6 J male mice were used. Inflammatory bone loss was induced by Porphyromonas gingivalis-lipopolysaccharide (P.g.-LPS) injections between the first and second maxillary molars, bilaterally, twice a week for 6 weeks (n = 20). AMG-487 NP were incorporated into a liposome carrier and locally delivered on sites where P.g.-LPS was injected. Control mice (n = 10) were injected with vehicle only. Experimental groups included (1) control, (2) LPS, and (3) LPS + NP. At the end of 1 and 6 weeks, mice were euthanized, maxillae harvested, fixed, and stored for further analysis. RESULTS: Volumetric bone loss analysis revealed, at 1 week, an increase in bone loss in the LPS group (47.9%) compared to control (27.4%) and LPS + NP (27.8%) groups. H&E staining demonstrated reduced inflammatory infiltrate in the LPS + NP group compared to LPS group. At 6 weeks, volumetric bone loss increased in all groups; however, treatment with the CXCR3 antagonist (LPS + NP) significantly reduced bone loss compared to the LPS group. CXCR3 antagonist treatment significantly reduced osteoclast numbers when compared to LPS group at 1 and 6 weeks. CONCLUSIONS: This study showed that local delivery of a CXCR antagonist, via nanoparticles, in a bone resorption model, induced by LPS injection, was effective in reducing inflammation, osteoclast numbers, and bone loss. CLINICAL RELEVANCE: CXCR3 blockade can be regarded as a novel target for therapeutic intervention of bone loss. It can be a safe and convenient method for periodontitis treatment or prevention applicable in clinical practice.