Electrospun PCL/gelatin/arbutin nanofiber membranes as potent reactive oxygen species scavengers to accelerate cutaneous wound healing.

The presence of excessive reactive oxygen species (ROS) at a skin wound site is an important factor affecting wound healing. ROS scavenging, which regulates the ROS microenvironment, is essential for wound healing. In this study, we used novel electrospun PCL/gelatin/arbutin (PCL/G/A) nanofibrous membranes as wound dressings, with PCL/gelatin (PCL/G) as the backbone, and plant-derived arbutin (hydroquinone-ß-d-glucopyranoside, ARB) as an effective antioxidant that scavenges ROS and inhibits bacterial infection in wounds. The loading of ARB increased the mechanical strength of the nanofibres, with a water vapour transmission rate of more than 2500 g/(m2 × 24 h), and the water contact angle decreased, indicating that hydrophilicity and air permeability were significantly improved. Drug release and degradation experiments showed that the nanofibre membrane controlled the drug release and exhibited favourable degradability. Haemolysis experiments showed that the PCL/G/A nanofibre membranes were biocompatible, and DPPH and ABTS+ radical scavenging experiments indicated that PCL/G/A could effectively scavenge ROS to reflect the antioxidant activity. In addition, haemostasis experiments showed that PCL/G/A had good haemostatic effects in vitro and in vivo. In vivo animal wound closure and histological staining experiments demonstrated that PCL/G/A increased collagen deposition and remodelled epithelial tissue regeneration while showing good in vivo biocompatibility and non-toxicity. In conclusion, we successfully prepared a multifunctional wound dressing, PCL/G/A, for skin wound healing and investigated its potential role in wound healing, which is beneficial for the clinical translational application of phytomedicines.

Mitochondrial-targeting and NIR-responsive Mn3O4@PDA@Pd-SS31 nanozymes reduce oxidative stress and reverse mitochondrial dysfunction to alleviate osteoarthritis.

Mitochondrial reactive oxygen species (mROS) play a crucial role in the process of osteoarthritis (OA), which may be a promising target for therapy of OA. In this study, novel mitochondrial-targeting and SOD-mimic Mn3O4@PDA@Pd-SS31 nanozymes with near-infrared (NIR) responsiveness and synergistic cascade to scavenge mROS were designed for the therapy of OA. Results showed that the nanozymes accelerated the release of Pd and Mn3O4 under NIR irradiation, exhibiting enhanced activities of SOD and CAT mimic enzymes with reversed mitochondrial dysfunction and promoted mitophagy to effectively scavenge mROS from chondrocytes, modulate the microenvironment of oxidative stress, and eventually inhibit the inflammatory response. Nanozymes were excreted in vivo through intestinal metabolic pathway and had good biocompatibility, effectively reducing the inflammatory response and relieving articular cartilage degeneration in OA joints, with a reduction of 93.7 % and 93.8 % in OARSCI scores for 4 and 8 weeks respectively. Thus, this study demonstrated that the mitochondria targeting and NIR responsive Mn3O4@PDA@Pd-SS31 nanozymes could efficiently scavenge mROS, repair damaged mitochondrial function and promote cartilage regeneration, which are promising for the treatment of OA in clinical applications.

Identification of autophagy-related genes in osteoarthritis articular cartilage and their roles in immune infiltration.

Background: Autophagy plays a critical role in the progression of osteoarthritis (OA), mainly by regulating inflammatory and immune responses. However, the underlying mechanisms remain unclear. This study aimed to investigate the potential relevance of autophagy-related genes (ARGs) associated with infiltrating immune cells in OA. Methods: GSE114007, GSE169077, and ARGs were obtained from the Gene Expression Omnibus (GEO) database and the Human Autophagy database. R software was used to identify the differentially expressed autophagy-related genes (DEARGs) in OA. Functional enrichment and protein-protein interaction (PPI) analyses were performed to explore the role of DEARGs in OA cartilage, and then Cytoscape was utilized to screen hub ARGs. Single-sample gene set enrichment analysis (ssGSEA) was used to conduct immune infiltration analysis and evaluate the potential correlation of key ARGs and immune cell infiltration. Then, the expression levels of hub ARGs in OA were further verified by the GSE169077 and qRT-PCR. Finally, Western blotting and immunohistochemistry were used to validate the final hub ARGs. Results: A total of 24 downregulated genes and five upregulated genes were identified, and these genes were enriched in autophagy, mitophagy, and inflammation-related pathways. The intersection results identified nine hub genes, namely, CDKN1A, DDIT3, FOS, VEGFA, RELA, MAP1LC3B, MYC, HSPA5, and HSPA8. GSE169077 and qRT-PCR validation results showed that only four genes, CDKN1A, DDT3, MAP1LC3B, and MYC, were consistent with the bioinformatics analysis results. Western blotting and immunohistochemical (IHC) showed that the expression of these four genes was significantly downregulated in the OA group, which is consistent with the qPCR results. Immune infiltration correlation analysis indicated that DDIT3 was negatively correlated with immature dendritic cells in OA, and FOS was positively correlated with eosinophils. Conclusion: CDKN1A, DDIT3, MAP1LC3B, and MYC were identified as ARGs that were closely associated with immune infiltration in OA cartilage. Among them, DDIT3 showed a strong negative correlation with immature dendritic cells. This study found that the interaction between ARGs and immune cell infiltration may play a crucial role in the pathogenesis of OA; however, the specific interaction mechanism needs further research to be clarified. This study provides new insights to further understand the molecular mechanisms of immunity involved in the process of OA by autophagy.

Analysis and identification of m6A RNA methylation regulators in metastatic osteosarcoma.

Osteosarcoma (OS) is characterized by rapid growth and early metastasis. However, its mechanism remains unclear. N6-methyladenosine (m6A) modification and its regulatory factors play essential roles in most cancers, including OS. In this study, we screened out 21 m6A modifiers using the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, followed by the identification of the critical m6A methylation modifiers. The results revealed that the expression levels of three m6A methylation regulators, namely RBM15, METTL3, and LRPPRC, were associated with the low survival rate of patients with OS. We further studied the independent prognostic factors by performing univariate and multivariate Cox analyses and found that metastasis was an independent prognostic factor for patients with OS. Furthermore, we found for the first time that RBM15 was specific for metastatic OS rather than non-metastatic OS. Moreover, the significant overexpression of RBM15 was validated in metastatic OS cell lines and in actual human clinical specimens. We also revealed that RBM15 promoted the invasion, migration, and metastasis of OS cells through loss-functional and gain-functional experiments and an animal metastatic model. In conclusion, RBM15 has a high correlation with OS metastasis formation and the decreased survival rate of patients with OS, and this may serve as a useful biomarker for predicting metastasis and prognosis of patients with OS.

pH-responsive and hyaluronic acid-functionalized metal-organic frameworks for therapy of osteoarthritis.

Drug therapy of osteoarthritis (OA) is limited by the short retention and lacking of stimulus-responsiveness after intra-articular (IA) injection. The weak acid microenvironment in joint provides a potential trigger for controlled drug release systems in the treatment of OA. Herein, we developed an pH-responsive metal - organic frameworks (MOFs) system modified by hyaluronic acid (HA) and loaded with an anti-inflammatory protocatechuic acid (PCA), designated as MOF@HA@PCA, for the therapy of OA. Results demonstrated that MOF@HA@PCA could smartly respond to acidic conditions in OA microenvironment and gradually release PCA, which could remarkably reduce synovial inflammation in both IL-1ß induced chondrocytes and the OA joints. MOF@HA@PCA also down-regulated the expression of inflammatory markers of OA and promoted the expression of cartilage-specific makers. This work may provide a new insight for the design of efficient nanoprobes for precision theranostics of OA .