Glucosamine sulfate-loaded nanofiber reinforced carboxymethyl chitosan sponge for articular cartilage restoration.

Cartilage is severely limited in self-repair after damage, and tissue engineering scaffold transplantation is considered the most promising strategy for cartilage regeneration. However, scaffolds without cells and growth factors, which can effectively avoid long cell culture times, high risk of infection, and susceptibility to contamination, remain scarce. Hence, we developed a cell- and growth factor-dual free hierarchically structured nanofibrous sponge to mimic the extracellular matrix, in which the encapsulated core-shell nanofibers served both as mechanical supports and as long-lasting carriers for bioactive biomass molecules (glucosamine sulfate). Under the protection of the nanofibers in this designed sponge, glucosamine sulfate could be released continuously for at least 30 days, which significantly accelerated the repair of cartilage tissue in a rat cartilage defect model. Moreover, the nanofibrous sponge based on carboxymethyl chitosan as the framework could effectively fill irregular cartilage defects, adapt to the dynamic changes during cartilage movement, and maintain almost 100 % elasticity even after multiple compression cycles. This strategy, which combines fiber freeze-shaping technology with a controlled-release method for encapsulating bioactivity, allows for the assembly of porous bionic scaffolds with hierarchical nanofiber structure, providing a novel and safe approach to tissue repair.

A Homozygous Variant in NAA60 Is Associated with Primary Familial Brain Calcification.

BACKGROUND: Primary familial brain calcification (PFBC) is a monogenic disorder characterized by bilateral calcifications in the brain. The genetic basis remains unknown in over half of the PFBC patients, indicating the existence of additional novel causative genes. NAA60 was a recently reported novel causative gene for PFBC. OBJECTIVE: The aim was to identify the probable novel causative gene in an autosomal recessive inherited PFBC family. METHODS: We performed a comprehensive genetic study on a consanguineous Chinese family with 3 siblings diagnosed with PFBC. We evaluated the effect of the variant in a probable novel causative gene on the protein level using Western blot, immunofluorescence, and coimmunoprecipitation. Possible downstream pathogenic mechanisms were further explored in gene knockout (KO) cell lines and animal models. RESULTS: We identified a PFBC co-segregated homozygous variant of c.460_461del (p.D154Lfs*113) in NAA60. Functional assays showed that this variant disrupts NAA60 protein localization to Golgi and accelerated protein degradation. The mutant NAA60 protein alters its interaction with the PFBC-related proteins PiT2 and XPR1, affecting intracellular phosphate homeostasis. Further mass spectrometry analysis in NAA60 KO cell lines revealed decreased expression of multiple brain calcification-associated proteins, including reduced folate carrier (RFC), a folate metabolism-related protein. CONCLUSIONS: Our study replicated the identification of NAA60 as a novel causative gene for autosomal recessive PFBC, demonstrating our causative variant leads to NAA60 loss of function. The NAA60 loss of function disrupts not only PFBC-related proteins (eg, PiT2 and XPR1) but also a wide range of other brain calcification-associated membrane protein substrates (eg, RFC), and provided a novel probable pathogenic mechanism for PFBC. © 2024 International Parkinson and Movement Disorder Society.

BI-7273, a BRD9 inhibitor, reduces lipid accumulation by downregulating the AKT/mTOR/SREBP1 signaling pathway.

Increases in de novo lipogenesis that disturbed lipid homeostasis and caused lipid accumulation are a major cause of NAFLD and obesity. SREBP1 is a crucial regulatory factor controlling the expression of rate-limiting enzymes of lipid synthesis. A reduction in SREBP1expression can reduce lipid accumulation. Thus, we utilized an SREBP1-luciferase-KI HEK293 cell line constructed by our lab to screen 200 kinds of epigenetic drugs for their ability to downregulate SREBP1expression. BI-7273, an inhibitor of bromodomain-containing protein 9 (BRD9), was screened and found to decrease SREBP1 expression. What is more, BI-7273 has been confirmed that it could reduce lipid accumulation in HepG2 cells by BODIPY staining, and significantly decrease the protein expression of SREBP1 and FASN. To explore the potential mechanism BI-7273 reducing lipid accumulation, RNA sequencing (RNA-seq) was performed and demonstrated that BI-7273 reduced lipid accumulation by downregulating the AKT/mTOR/SREBP1 pathway in vitro. Finally, these results were verified in NAFLD and obesity mouse model induced by high fat diet (HFD). The results indicated that BI-7273 could decrease mouse body weight and improve insulin sensitivity, but also exhibited a strong negative correlation with serum lipid levels, and also demonstrated that BI-7273 reduced lipid accumulation via AKT/mTOR/SREBP1 pathway in vivo. In conclusion, our results revealed that BI-7273 decreases lipid accumulation by downregulating the AKT/mTOR/SREBP1 pathway in vivo and in vitro. This is the first report demonstrating the protective effect of this BRD9 inhibitor against NAFLD and obesity. BRD9 may be a novel target for the discovery of effective drugs to treat lipid metabolism disorders.

Production and characterization of novel monoclonal antibodies against pathological human TDP-43 proteins.

The RNA/DNA-binding protein TDP-43 plays a pivotal role in the ubiquitinated inclusions characteristic of TDP-43 proteinopathies, including most cases of frontotemporal lobar degeneration (FTLD-TDP) and Alzheimer disease (AD). To understand the mechanisms of pathological TDP-43 processing and identify potential biomarkers, we generated novel phosphorylation-independent monoclonal antibodies (MAbs) using bacteria-expressed human full-length recombinant TDP-43. Remarkably, we identified a distinctive MAb, No. 9, targeting an epitope in amino acid (aa) region 311-360 of the C-terminus. This antibody showed preferential reactivity for pathological TDP-43 inclusions, with only mild reactivity for normal nuclear TDP-43. MAb No. 9 revealed more pathology in FTLD-TDP type A and type B brains and in AD brains compared to the commercial p409/410 MAb. Using synthetic phosphorylated peptides, we also obtained MAbs targeting the p409/410 epitope. Interestingly, MAb No. 14 was found to reveal additional pathology in AD compared to the commercial p409/410 MAb, specifically, TDP-43-immunopositive deposits with amyloid plaques in AD brains. These unique immunopositivities observed with MAbs No. 9 and No. 14 are likely attributed to their conformation-dependent binding to TDP-43 inclusions. We expect that this novel set of MAbs will prove valuable as tools for future patient-oriented investigations into TDP-43 proteinopathies.

Effectiveness of a flipped classroom for undergraduate in implant dentistry hands-on course.

PURPOSE: The purpose of this study was to compare the learning in the implant dentistry hands-on course to that of the flipped classroom (FC) and the traditional lecture cohorts (control). MATERIALS AND METHODS: In this study,80 students were enrolled for the first time in an implant dentistry program. Subsequently, they were divided into two groups. The first, the FC group, which had free access to a video with a PowerPoint presentation on the Chaoxing-WHU-MOOC platform about the implant placement on first molar sites before class. The second, the control group, which attended a didactic lecture describing implant practice on the first molar site via a bidirectional multimedia interactive teaching demonstration and then operated on a simulation model. Cone beam computed tomography (CBCT) and the deviation gauge were utilized to analyze the accuracy of the implant placement in the students' models. An online satisfaction questionnaire was distributed to both groups one week after the class. RESULTS: The linear deviation of the CBCT examination did not show any statistical difference between the two groups concerning cervical, apex, and angular. A significant buccal deviation was observed in the control group compared with the FC group (mean: 0.7436 mm vs. 0.2875 mm, p = 0.0035), according to the restoration-level deviation gauge. A total of 74.36% of students in the FC group placed implant within 0.5 mm buccal-to-lingual deviations, but only 41.03% of students in the control group reached within 0.5 mm buccal-to-lingual deviation ranges. Additionally, 91.67% of the students in the FC group and 97.5% of the students in the control group were satisfied with the practical implant class. CONCLUSION: FC was more effective than a didactic lecture for implant dentistry practical skill acquisition.

Four New Species and One New Record of Thelephora from China.

Species of the genus Thelephora (Thelephorales, Thelephoraceae) are ectomycorrhizal symbionts of coniferous and broad-leaved plants, and some of them are well-known edible mushrooms, making it an exceptionally important group ecologically and economically. However, the diversity of the species from China has not been fully elucidated. In this study, we conducted a phylogenetic analysis based on the internal transcribed spacer (ITS) regions, using Maximum Likelihood and Bayesian analyses, along with morphological observations of this genus. Four new species from China are proposed, viz., T. dactyliophora, T. lacunosa, T. petaloides, and T. pinnatifida. In addition, T. sikkimensis originally described from India is reported for the first time from China. Thelephora dactyliophora, T. pinnatifida, and T. sikkimensis are distributed in subtropical forests and mainly associated with plants of the families Fagaceae and Pinaceae. Thelephora lacunosa and T. petaloides are distributed in tropical to subtropical forests. Thelephora lacunosa is mainly associated with plants of the families Fagaceae and Pinaceae, while T. petaloides is mainly associated with plants of the family Fagaceae. Line drawings of microstructures, color pictures of fresh basidiomes, and detailed descriptions of these five species are provided.

ROS-Induced Gingival Fibroblast Senescence: Implications in Exacerbating Inflammatory Responses in Periodontal Disease.

Periodontal disease is the pathological outcome of the overwhelming inflammation in periodontal tissue. Cellular senescence has been associated with chronic inflammation in several diseases. However, the role of cellular senescence in the pathogenesis of periodontal disease remained unclear. This study aimed to investigate the role and the mechanism of cellular senescence in periodontal disease. Using single-cell RNA sequencing, we first found the upregulated level of cellular senescence in fibroblasts and endothelial cells from inflamed gingival tissue. Subsequently, human gingival fibroblasts isolated from healthy and inflamed gingival tissues were labeled as H-GFs and I-GFs, respectively. Compared to H-GFs, I-GFs exhibited a distinct cellular senescence phenotype, including an increased proportion of senescence-associated ß-galactosidase (SA-ß-gal) positive cells, enlarged cell morphology, and significant upregulation of p16INK4A expression. We further observed increased cellular reactive oxygen species (ROS) activity, mitochondrial ROS, and DNA damage of I-GFs. These phenotypes could be reversed by ROS scavenger NAC, which suggested the cause of cellular senescence in I-GFs. The migration and proliferation assay showed the decreased activity of I-GFs while the gene expression of senescence-associated secretory phenotype (SASP) factors such as IL-1ß, IL-6, TGF-ß, and IL-8 was all significantly increased. Finally, we found that supernatants of I-GF culture induced more neutrophil extracellular trap (NET) formation and drove macrophage polarization toward the CD86-positive M1 pro-inflammatory phenotype. Altogether, our findings implicate that, in the inflamed gingiva, human gingival fibroblasts acquire a senescent phenotype due to oxidative stress-induced DNA and mitochondrial damage, which in turn activate neutrophils and macrophages through the secretion of SASP factors.

Leukemia inhibitory factor protects against experimental periodontitis through immuno-modulations of both macrophages and periodontal ligament fibroblasts.

BACKGROUND: To explore the role of leukemia inhibitory factor (LIF) in periodontitis via in vivo and in vitro experiments. METHODS: The second upper molar of LIF knockout mice and their wild-type littermates were ligated for 8 days. Micro-computed tomography (micro-CT), histological analysis, and quantitative real-time polymerase chain reaction (qRT-PCR) were performed. The expression levels of proinflammatory cytokines were examined in mouse bone marrow derived macrophages and human periodontal ligament fibroblasts (HPDLFs) after lipopolysaccharide (LPS) treatment. RESULTS: LIF deficiency promoted alveolar bone loss, inflammatory cells infiltration, osteoclasts formation and collagen fiber degradation in ligature-induced mouse, along with higher expressions of proinflammatory cytokines, including interleukin-6 (IL6), IL-1ß (IL1B), tumor necrosis factor-α (TNFA), matrix metalloproteinase 13 (MMP13), and RANKL/OPG ratio. Additionally, LIF deletion led to higher expression levels of these proinflammatory cytokines in mouse bone marrow-derived macrophages from both femur and alveolar bone and HPDLFs when treated with LPS. Administration of recombined LIF attenuated TNFA, IL1B, and RANKL/OPG ratio in HPDLFs. CONCLUSIONS: These findings indicate that LIF deficiency promotes the progress of periodontitis via modulating immuno-inflammatory responses of macrophages and periodontal ligament fibroblasts, and the application of LIF may be an adjunctive treatment for periodontitis to resolute inflammation.

The Critical Role of Pyroptosis in Peri-Implantitis.

Background: Peri-implantitis (PI) is a prevalent complication of implant treatment. Pyroptosis, a distinctive inflammatory programmed cell death, is crucial to the pathophysiology of PI. Despite its importance, the pyroptosis-related genes (PRGs) influencing PI's progression remain largely unexplored. Methods: This study conducted histological staining and transcriptome analyze from three datasets. The intersection of differentially expressed genes (DEGs) and PRGs was identified as pyroptosis-related differentially expressed genes (PRDEGs). Functional enrichment analyses were conducted to shed light on potential underlying mechanisms. Weighted Gene Co-expression Network Analysis (WGCNA) and a pyroptotic macrophage model were utilized to identify and validate hub PRDEGs. Immune cell infiltration in PI and its relationship with hub PRDEGs were also examined. Furthermore, consensus clustering was performed to identify new PI subtypes. Protein-protein interaction (PPI) network, competing endogenous RNA (ceRNA) network, mRNA-mRNA binding protein regulatory (RBP) network, and mRNA-drugs regulatory network of hub PRDEGs were also analyzed. Results: Eight hub PRDEGs were identified: PGF, DPEP1, IL36B, IFIH1, TCEA3, RIPK3, NET7, and TLR3, which are instrumental in the PI's progression. Two PI subtypes were distinguished, with Cluster 1 exhibiting higher immune cell activation. The exploration of regulatory networks provided novel mechanisms and therapeutic targets in PI. Conclusion: Our research highlights the critical role of pyroptosis and identifies eight hub PRDEGs in PI's progression, offering insights into novel immunotherapy targets and laying the foundation for advanced diagnostic and treatment strategies. This contributes to our understanding of PI and underscores the potential for personalized clinical management.

Immediate versus Non-immediate Loading Protocols for Reduced-diameter Implants Supporting Overdentures: A Systematic Review and Meta-analysis.

OBJECTIVE: This systematic review aimed to compare the influence of immediate and non-immediate loading protocols on overdentures retained by reduced-diameter implants(≦3.5mm). METHODS: Electronic databases, including MEDLINE (via PubMed), Embase and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) comparing clinical outcomes of immediately and nonimmediately loaded reduced-diameter implants supported overdentures. The risk of bias within and across the studies and the certainty of evidence were assessed by RoB 2.0 and GRADE, respectively. Sensitivity analysis was performed by eliminating studies at high risk of bias, and repeating the data synthesis employing the randomeffect model. Subgroup analyses were conducted based on the implant diameter and the length of follow-up. RESULTS: Six RCTs with 255 patients were included in this systematic review. The meta-analyses found similar implant survival rates between immediate and nonimmediate loaded implants in mini implant (RR=0.98; 95% CI=0.95, 1.01; p=0.12) and narrow implant subgroups (RR=0.99, 95% CI=0.94, 1.03, p =0.56), as well as in short-term (RR=0.98, 95% CI=0.97, 1.00, p =0.11) and long-term (RR=0.97, 95% CI=0.93, 1.01, p =0.09) follow-up subgroups. Additionally, marginal bone loss (MBL) showed no statistically significant difference between the loading protocols in the subgroup of long-term follow-up (MD=0.03; 95%CI=-0.16, 0.23; p=0.74). Three RCTs investigating peri-implant parameters found relatively higher modified plaque index and probing depth in reduced-diameter implant under immediate loading. CONCLUSION: Compared with non-immediate loading, the immediately loading protocol can achieve comparable survival rates and MBL in reduced-diameter implant retained overdentures.

Comparison of the osteogenic potential of fibroblasts from different sources.

OBJECTIVE: With the growing interest in the role of fibroblasts in osteogenesis, this study presents a comparative evaluation of the osteogenic potential of fibroblasts derived from three distinct sources: human gingival fibroblasts (HGFs), mouse embryonic fibroblasts (NIH3T3 cells), and mouse subcutaneous fibroblasts (L929 cells). MC3T3-E1 pre-osteoblast cells were employed as a positive control for osteogenic behavior. DESIGN: Our assessment involved multiple approaches, including vimentin staining for cell origin verification, as well as ALP and ARS staining in conjunction with RT-PCR for osteogenic characterization. RESULTS: Our findings revealed the superior osteogenic differentiation capacity of HGFs compared to MC3T3-E1 and NIH3T3 cells. Analysis of ALP staining confirmed that early osteogenic differentiation was most prominent in MC3T3-E1 cells at 7 days, followed by NIH3T3 and HGFs. However, ARS staining at 21 days demonstrated that HGFs produced the highest number of calcified nodules, indicating their robust potential for late-stage mineralization. This late-stage osteogenic potential of HGFs was further validated through RT-PCR analysis. In contrast, L929 cells displayed no significant osteogenic differentiation potential. CONCLUSIONS: In light of these findings, HGFs emerge as the preferred choice for seed cells in bone tissue engineering applications. This study provides valuable insights into the potential utility of HGFs in the fields of bone tissue engineering and regenerative medicine.

FAM76B regulates PI3K/Akt/NF-κB-mediated M1 macrophage polarization by influencing the stability of PIK3CD mRNA.

Macrophage polarization is closely related to inflammation development, yet how macrophages are polarized remains unclear. In our study, the number of M1 macrophages was markedly increased in Fam76b knockout U937 cells vs. wild-type U937 cells, and FAM76B expression was decreased in M1 macrophages induced from different sources of macrophages. Moreover, Fam76b knockout enhanced the mRNA and protein levels of M1 macrophage-associated marker genes. These results suggest that FAM76B inhibits M1 macrophage polarization. We then further explored the mechanism by which FAM76B regulates macrophage polarization. We found that FAM76B can regulate PI3K/Akt/NF-κB pathway-mediated M1 macrophage polarization by stabilizing PIK3CD mRNA. Finally, FAM76B was proven to protect against inflammatory bowel disease (IBD) by inhibiting M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vivo. In summary, FAM76B regulates M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vitro and in vivo, which may inform the development of future therapeutic strategies for IBD and other inflammatory diseases.

Rat Peri-implantitis Models: A Systematic Review and Meta-analysis.

PURPOSE: To review experimental peri-implantitis studies using rat models and summarize different peri-implantitis induction techniques and evaluate their effectiveness. MATERIALS AND METHODS: Electronic searches were conducted by two independent examiners to address the following issues. Meta-analyses explored the marginal bone loss (MBL) of four types of peri-implantitis induction methods in rats. The detailed induction tactics-such as the implant design, implant size, surgical process, time cost, induction methods, and endpoint measurements-were summarized. RESULTS: Of the 18 included studies, 38.9% of the studies placed implants at the maxillary first molar, and 44.4% placed them at the alveolar ridge region anterior to the maxillary first molar. As for the induction method, the numbers of published studies on ligature methods, bacterial inoculation, and bacterial lipopolysaccharide inoculation were equally high among all selected studies. The total implant survival rate at the end was 160 out of 213 implants (75.11%). Eight studies with high pooled heterogeneity (I2 = 98, P < .01) in the meta-analysis reported an overall MBL (µ-CT) of 0.47 mm (95% CI = 0.14 to 0.81). A subgroup analysis estimated an MBL of 0.31 mm (95% CI = 0.12 to 0.50) for bacterial inoculation and 0.66 mm (95% CI = 0.07 to 1.26) for the ligature method. Histopathologic analysis revealed that peri-implantitis in rats was similar to peri-implantitis lesions in humans. CONCLUSIONS: Implant placement at the maxillary first molar with bacterial inoculation and the silk ligature method to build peri-implantitis rat models is reliable to use for research on peri-implantitis.

S-nitrosoglutathione reductase-dependent p65 denitrosation promotes osteoclastogenesis by facilitating recruitment of p65 to NFATc1 promoter.

Osteoclasts, the exclusive bone resorptive cells, are indispensable for bone remodeling. Hence, understanding novel signaling modulators regulating osteoclastogenesis is clinically important. Nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) is a master transcription factor in osteoclastogenesis, and binding of NF-κB p65 subunit to NFATc1 promoter is required for its expression. It is well-established that DNA binding activity of p65 can be regulated by various post-translational modifications, including S-nitrosation. Recent studies have demonstrated that S-nitrosoglutathione reductase (GSNOR)-mediated protein denitrosation participated in cell fate commitment by regulating gene transcription. However, the role of GSNOR in osteoclastogenesis remains unexplored and enigmatic. Here, we investigated the effect of GSNOR-mediated denitrosation of p65 on osteoclastogenesis. Our results revealed that GSNOR was up-regulated during osteoclastogenesis in vitro. Moreover, GSNOR inhibition with a chemical inhibitor impaired osteoclast differentiation, podosome belt formation, and bone resorption activity. Furthermore, GSNOR inhibition enhanced the S-nitrosation level of p65, precluded the binding of p65 to NFATc1 promoter, and suppressed NFATc1 expression. In addition, mouse model of lipopolysaccharides (LPS)-induced calvarial osteolysis was employed to evaluate the therapeutic effect of GSNOR inhibitor in vivo. Our results indicated that GSNOR inhibitor treatment alleviated the inflammatory bone loss by impairing osteoclast formation in mice. Taken together, these data have shown that GSNOR activity is required for osteoclastogenesis by facilitating binding of p65 to NFATc1 promoter via promoting p65 denitrosation, suggesting that GSNOR may be a potential therapeutic target in the treatment of osteolytic diseases.

Janus silk fibroin/polycaprolactone-based scaffold with directionally aligned fibers and porous structure for bone regeneration.

To promote bone repair, it is desirable to develop three-dimensional multifunctional fiber scaffolds. The densely stacked and tightly arranged conventional two-dimensional electrospun fibers hinder cell penetration into the scaffold. Most of the existing three-dimensional structural materials are isotropic and monofunctional. In this research, a Janus nanofibrous scaffold based on silk fibroin/polycaprolactone (SF/PCL) was fabricated. SF-encapsulated SeNPs demonstrated stability and resistance to aggregation. The outside layer (SF/PCL/Se) of the Janus nanofiber scaffold displayed a structured arrangement of fibers, facilitating cell growth guidance and impeding cell invasion. The inside layer (SF/PCL/HA) featured a porous structure fostering cell adhesion. The Janus fiber scaffold containing SeNPs notably suppressed S. aureus and E. coli activities, correlating with SeNPs concentration. In vitro, findings indicated considerable enhancement in alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts and upregulation of genes linked to osteogenic differentiation with exposure to the SF/PCL/HA/Se Janus nanofibrous scaffold. Moreover, in vivo, experiments demonstrated successful critical bone defect repair in mouse skulls using the SF/PCL/HA/Se Janus nanofiber scaffold. These findings highlight the potential of the SF/PCL-based Janus nanofibrous scaffold, integrating SeNPs and nHA, as a promising biomaterial in bone tissue engineering.

Biphasic calcium phosphate recruits Tregs to promote bone regeneration.

The use of bone substitute materials is crucial for the healing of large bone defects. Immune response induced by bone substitute materials is essential in bone regeneration. Prior research has mainly concentrated on innate immune cells, such as macrophages. Existing research suggests that T lymphocytes, as adaptive immune cells, play an indispensable role in bone regeneration. However, the mechanisms governing T cell recruitment and specific subsets that are essential for bone regeneration remain unclear. This study demonstrates that CD4+ T cells are indispensable for ectopic osteogenesis by biphasic calcium phosphate (BCP). Subsequently, the recruitment of CD4+ T cells is closely associated with the activation of calcium channels in macrophages by BCP to release chemokines Ccl3 and Ccl17. Finally, these recruited CD4+ T cells are predominantly Tregs, which play a significant role in ectopic osteogenesis by BCP. These findings not only shed light on the immune-regenerative process after bone substitute material implantation but also establish a theoretical basis for developing bone substitute materials for promoting bone tissue regeneration. STATEMENT OF SIGNIFICANCE: Bone substitute material implantation is essential in the healing of large bone defects. Existing research suggests that T lymphocytes are instrumental in bone regeneration. However, the specific mechanisms governing T cell recruitment and specific subsets that are essential for bone regeneration remain unclear. In this study, we demonstrate that activation of calcium channels in macrophages by biphasic calcium phosphate (BCP) causes them to release the chemokines Ccl3 and Ccl17 to recruit CD4+ T cells, predominantly Tregs, which play a crucial role in ectopic osteogenesis by BCP. Our findings provide a theoretical foundation for developing bone substitute material for bone tissue regeneration.

Enhancing Bone Regeneration through CDC20-Loaded ZIF-8 Nanoparticles Wrapped in Erythrocyte Membranes with Targeting Aptamer.

In the context of bone regeneration, nanoparticles harboring osteogenic factors have emerged as pivotal agents for modulating the differentiation fate of stem cells. However, persistent challenges surrounding biocompatibility, loading efficiency, and precise targeting ability warrant innovative solution. In this study, a novel nanoparticle platform founded upon the zeolitic imidazolate framework-8 (ZIF-8) is introduced. This new design, CDC20@ZIF-8@eM-Apt, involves the envelopment of ZIF-8 within an erythrocyte membrane (eM) cloak, and is coupled with a targeting aptamer. ZIF-8, distinguished by its porosity, biocompatibility, and robust cargo transport capabilities, constitutes the core framework. Cell division cycle protein 20 homolog (CDC20) is illuminated as a new target in bone regeneration. The eM plays a dual role in maintaining nanoparticle stability and facilitating fusion with target cell membranes, while the aptamer orchestrates the specific recruitment of bone marrow mesenchymal stem cells (BMSCs) within bone defect sites. Significantly, CDC20@ZIF-8@eM-Apt amplifies osteogenic differentiation of BMSCs via the inhibition of NF-κB p65, and concurrently catalyzes bone regeneration in two bone defect models. Consequently, CDC20@ZIF-8@eM-Apt introduces a pioneering strategy for tackling bone defects and associated maladies, opening novel avenues in therapeutic intervention.

Thy-1 knockdown promotes the osteogenic differentiation of GMSCs via the Wnt/ß-catenin pathway.

Gingival mesenchymal stem cells (GMSCs) are newly developed seed cells for tissue engineering owing to their easy isolation, abundance and high growth rates. Thy-1 is an important regulatory molecule in the differentiation of mesenchymal stem cells (MSCs). In this study, we investigated the function of Thy-1 in the osteogenic differentiation of GMSCs by reducing the expression of Thy-1 using a lentivirus. The results demonstrated that Thy-1 knockdown promoted the osteogenic differentiation of GMSCs in vitro. Validation by RNA-seq revealed an obvious decrease in Vcam1 and Sox9 gene expression with Thy-1 knockdown. Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that the differentially expressed genes were enriched in the Wnt signalling pathway. We further demonstrated that Thy-1 knockdown promoted osteogenic differentiation of GMSCs by activating the Wnt/ß-catenin signalling pathway. Therefore, Thy-1 has a key regulatory role in the differentiation of GMSCs and maybe a core molecule connecting transcription factors related to the differentiation of MSCs. Our study also highlighted the potential of Thy-1 to modify MSCs, which may help improve their use in tissue engineering.

Expression and functional analysis of fam76b in zebrafish.

FAM76B is nuclear speckle-localized protein with a molecular weight of 39 kDa. The amino sequence of FAM76B protein is highly conserved among species, suggesting that FAM76B has important biological functions. However, the biological function of FAM76B is currently still unclear. To explore the biological function of FAM76B, we firstly used zebrafish as the experimental model to study the distribution and expression level of Fam76b. The results indicated that fam76b is highly expressed in hematopoiesis and immune systems of zebrafish by real-time quantitative PCR, in situ hybridization and Tg(fam76b: eGFP) transgenic zebrafish. Then, the fam76b gene was knocked out by CRISPR/Cas9 in zebrafish and fam76b rescue in fam76b-/- zebrafish was performed using the TOL2 transposable system. fam76b gene knockout zebrafish exhibit reduced thymus, excessive inflammatory response, and increased mortality. FAM76B was further found to be involved in regulating the development of hematopoiesis and immune system, and participate in the process of inflammatory response. Our findings in the study lay the groundwork for elucidating the function of the new molecule Fam76b and provide new insights into the development of zebrafish hematopoietic and immune system.

Role of dendritic cells in MYD88-mediated immune recognition and osteoinduction initiated by the implantation of biomaterials.

Bone substitute material implantation has become an important treatment strategy for the repair of oral and maxillofacial bone defects. Recent studies have shown that appropriate inflammatory and immune cells are essential factors in the process of osteoinduction of bone substitute materials. Previous studies have mainly focused on innate immune cells such as macrophages. In our previous work, we found that T lymphocytes, as adaptive immune cells, are also essential in the osteoinduction procedure. As the most important antigen-presenting cell, whether dendritic cells (DCs) can recognize non-antigen biomaterials and participate in osteoinduction was still unclear. In this study, we found that surgical trauma associated with materials implantation induces necrocytosis, and this causes the release of high mobility group protein-1 (HMGB1), which is adsorbed on the surface of bone substitute materials. Subsequently, HMGB1-adsorbed materials were recognized by the TLR4-MYD88-NFκB signal axis of dendritic cells, and the inflammatory response was activated. Finally, activated DCs release regeneration-related chemokines, recruit mesenchymal stem cells, and initiate the osteoinduction process. This study sheds light on the immune-regeneration process after bone substitute materials implantation, points out a potential direction for the development of bone substitute materials, and provides guidance for the development of clinical surgical methods.