Sulfasalazine promotes ferroptosis through AKT-ERK1/2 and P53-SLC7A11 in rheumatoid arthritis.

OBJECTIVE: Ferroptosis has been reported to play a role in rheumatoid arthritis (RA). Sulfasalazine, a common clinical treatment for ankylosing spondylitis, also exerts pathological influence on the progression of rheumatoid arthritis including the induced ferroptosis of fibroblast-like synoviocytes (FLSs), which result in the perturbated downstream signaling and the development of RA. The aim of this study was to investigate the underlying mechanism so as to provide novel insight for the treatment of RA. METHODS: CCK-8 and Western blotting were used to assess the effect of sulfasalazine on FLSs. A collagen-induced arthritis mouse model was constructed by the injection of collagen and Freund's adjuvant, and then, mice were treated with sulfasalazine from day 21 after modeling. The synovium was extracted and ferroptosis was assessed by Western blotting and immunofluorescence staining. RESULTS: The results revealed that sulfasalazine promotes ferroptosis. Compared with the control group, the expression levels of ferroptosis-related proteins such as glutathione peroxidase 4, ferritin heavy chain 1, and solute carrier family 7, member 11 (SLC7A11) were lower in the experimental group. Furthermore, deferoxamine inhibited ferroptosis induced by sulfasalazine. Sulfasalazine-promoted ferroptosis was related to a decrease in ERK1/2 and the increase of P53. CONCLUSIONS: Sulfasalazine promoted ferroptosis of FLSs in rheumatoid arthritis, and the PI3K-AKT-ERK1/2 pathway and P53-SLC7A11 pathway play an important role in this process.

Neglected immunoregulation: M2 polarization of macrophages triggered by low-dose irradiation plays an important role in bone regeneration.

Current studies have found that low-dose irradiation (IR) can promote bone regeneration. However, mechanism studies of IR-triggered bone regeneration mainly focus on the effects of osteoblasts, neglecting the role of the surrounding immune microenvironment. Here in this study, in vitro proliferation experiments showed that low-dose IR ≤2 Gy could promote the proliferation of bone marrow mesenchymal stem cells (BMSCs), and qRT-PCR assay showed that low-dose IR ≤2 Gy could exert the M2 polarization of Raw264.7 cells, while IR >2 Gy inhibited BMSC proliferation and triggered M1 polarization in Raw264.7 cells. The ALP and mineralized nodules staining showed that low-dose IR ≤2 Gy not only promoted osteoblast mineralization through IR-triggered osteoblast proliferation but also through M2 polarization of Raw264.7 cells, while high-dose IR >2 Gy had the opposite effect. The co-incubation of BMSC with low-dose IR irradiated Raw264.7 cell supernatants increased the mRNA expression of BMP-2 and Osx. The rat cranial defects model revealed that low-dose IR ≤2 Gy gradually promoted bone regeneration, while high-dose IR >2 Gy inhibited bone regeneration. Detection of macrophage polarity in peripheral blood samples showed that low-dose IR ≤2 Gy increased the expression of CD206 and CD163, but decreased the expression of CD86 and CD80 in macrophages, which indicated M2 polarization of macrophages in vivo, while high-dose IR had the opposite effect. Our finding innovatively revealed that low-dose IR ≤2 Gy promotes bone regeneration not only by directly promoting the proliferation of osteoblasts but also by triggering M2 polarization of macrophages, which provided a new perspective for immune mechanism study in the treatment of bone defects with low-dose IR.

Biomineralized tetramethylpyrazine-loaded PCL/gelatin nanofibrous membrane promotes vascularization and bone regeneration of rat cranium defects.

Conventional electrospinning produces nanofibers with smooth surfaces that limit biomineralization ability. To overcome this disadvantage, we fabricated a tetramethylpyrazine (TMP)-loaded matrix-mimicking biomineralization in PCL/Gelatin composite electrospun membranes with bubble-shaped nanofibrous structures. PCL/Gelatin membranes (PG), PCL/Gelatin membranes containing biomineralized hydroxyapatite (HA) (PGH), and PCL/Gelatin membranes containing biomineralized HA and loaded TMP (PGHT) were tested. In vitro results indicated that the bubble-shaped nanofibrous surface increased the surface roughness of the nanofibers and promoted mineralization. Furthermore, sustained-release TMP had an excellent drug release efficiency. Initially released vigorously, it reached stabilization at day 7, and the slow-release rate stabilized at 61.0 ± 1.8% at 28 days. All membranes revealed an intact cytoskeleton, cell viability, and superior adhesion and proliferation when stained with Ghost Pen Cyclic Peptide, CCK-8, cell adhesion, and EdU. In PGHT membranes, the osteogenic and vascularized gene expression of BMSCs and human vascular endothelial cells was significantly upregulated compared with that in other groups, indicating the PGHT membranes exhibited an effective vascularization role. Subsequently, the membranes were implanted in a rat cranium defect model for 4 and 8 weeks. Micro-CT and histological analysis results showed that the PGHT membranes had better bone regenerative patterns. Additionally, the levels of CD31 and VEGF significantly increased in the PGHT membrane compared with those in other membranes. Thus, PGHT membranes could accelerate the repair of cranium defects in vivo via HA and TMP synergistic effects.

Angelica sinensis polysaccharide improves mitochondrial metabolism of osteoarthritis chondrocytes through PPARγ/SOD2/ROS pathways.

Osteoarthritis (OA) is a common degenerative joint disease, which is characterized by wear of articular cartilage and narrow joint space, resulting in joint movement disorder. At present, accurate molecular mechanisms and effective interventions are still being explored. Here, we propose that angelica sinensis polysaccharide (ASP) alleviates OA progression by activating peroxisome proliferator-activated receptor gamma (PPARγ). Therapeutic effect of ASP improving mitochondrial metabolism of OA chondrocytes was evaluated in vitro and in vivo, respectively. During cell experiments, the concentration and time response of tert butyl hydroperoxide (TBHP) and ASP were determined by cell viability. Apoptosis was detected by flow cytometry. Mitochondrial metabolism was detected by reactive oxygen species (ROS), mitochondrial membrane potential (MMP), release of cytochrome C, adenosine triphosphate (ATP) production, and superoxide dismutase 2 (SOD2) activity. Expressions of Aggrecan, collagen type II (Col2a1), PPARγ, and SOD2 were detected by qRT-PCR and western blot. In animal experiments, we detected cell apoptosis and target protein expression separately through terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining and immunohistochemistry. Pretreatment of ASP significantly activated PPARγ and SOD2 in rat chondrocytes incubated with TBHP, cleared ROS, improved mitochondrial metabolism, increased chondrocytes viability, and alleviated chondrocytes apoptosis. In vivo, the administration of ASP could effectively ameliorate cartilage degeneration in OA rats, promote extracellular matrix synthesis, and decelerate the progress of OA. Our research identifies the role of ASP in mitochondrial metabolism of OA chondrocytes through PPARγ/SOD2/ROS pathways, which provides a new idea for the treatment of OA.

[Obesity and hypertriglyceridemia: high risks for disease severity and mortality in COVID-19 patients].

As COVID-19 pandemic approaching its third year, more data have shown that obesity and hypertriglyceridemia are the high-risk factors for the major complications such as acute respiratory distress syndrome, thromboembolism, coagulopathy and cytokine storm, which are responsible for the majority of disease severity and mortality. In this review article, we have analyzed the public available clinical reports and laboratory research results of the COVID-19 studies by researchers and clinicians of many nations around the world. Many of these reports covered COVID-19 patients of different ethnic groups. We suggested that obesity and high triglycerides are high risks for severe COVID-19 and death. We also summarized the possible underlying molecular mechanism likely connecting the severe COVID-19 with obesity and hypertriglyceridemia. From public health perspective, we highlight the importance of the healthy diet and lifestyle in fighting against SARS-CoV-2 virus in long period of time.

The Cysteine-Rich Peptide Snakin-2 Negatively Regulates Tubers Sprouting through Modulating Lignin Biosynthesis and H2O2 Accumulation in Potato.

Potato tuber dormancy is critical for the post-harvest quality. Snakin/Gibberellic Acid Stimulated in Arabidopsis (GASA) family genes are involved in the plants' defense against pathogens and in growth and development, but the effect of Snakin-2 (SN2) on tuber dormancy and sprouting is largely unknown. In this study, a transgenic approach was applied to manipulate the expression level of SN2 in tubers, and it demonstrated that StSN2 significantly controlled tuber sprouting, and silencing StSN2 resulted in a release of dormancy and overexpressing tubers showed a longer dormant period than that of the control. Further analyses revealed that the decrease expression level accelerated skin cracking and water loss. Metabolite analyses revealed that StSN2 significantly down-regulated the accumulation of lignin precursors in the periderm, and the change of lignin content was documented, a finding which was consistent with the precursors' level. Subsequently, proteomics found that cinnamyl alcohol dehydrogenase (CAD), caffeic acid O-methyltransferase (COMT) and peroxidase (Prx), the key proteins for lignin synthesis, were significantly up-regulated in silencing lines, and gene expression and enzyme activity analyses also supported this effect. Interestingly, we found that StSN2 physically interacts with three peroxidases catalyzing the oxidation and polymerization of lignin. In addition, SN2 altered the hydrogen peroxide (H2O2) content and the activities of superoxide dismutase (SOD) and catalase (CAT). These results suggest that StSN2 negatively regulates lignin biosynthesis and H2O2 accumulation, and ultimately inhibits the sprouting of potato tubers.

LncRNA LUADT1 regulates miR-34a/SIRT1 to participate in chondrocyte apoptosis.

It is known that miR-34a can promote the apoptosis of chondrocytes, which directly contribute to osteoarthritis (OA). Through bioinformatics analysis, we found that long noncoding RNA LUADT1 may interact with miR-34a. We, therefore, further investigate the interactions between them in osteoarthritis. We found that LUADT1 was downregulated, while miR-34a was upregulated in OA synovial fluid. Correlation analysis revealed no significant correlation between them. Overexpression experiment also revealed no significant effects of LUADT1 and miR-34a on the expression of each other. However, the dual-luciferase assay showed that LUADT1 and miR-34a can directly interact with each other. Moreover, LUADT1 overexpression led to the upregulation of SIRT1, which is a downstream target of miR-34a. Cell apoptosis showed that LUADT1 and SIRT1 overexpression led to decreased, while miR-34a led to increased apoptotic rates of chondrocytes. Therefore, LUADT1 regulates miR-34a/SIRT1 to participate in chondrocyte apoptosis.

Quantitative Proteomic Analysis of Alligator Weed Leaves Reveals That Cationic Peroxidase 1 Plays Vital Roles in the Potassium Deficiency Stress Response.

Alligator weed is reported to have a strong ability to adapt to potassium deficiency (LK) stress. Leaves are the primary organs responsible for photosynthesis of plants. However, quantitative proteomic changes in alligator weed leaves in response to LK stress are largely unknown. In this study, we investigated the physiological and proteomic changes in leaves of alligator weed under LK stress. We found that chloroplast and mesophyll cell contents in palisade tissue increased, and that the total chlorophyll content, superoxide dismutase (SOD) activity and net photosynthetic rate (PN) increased after 15 day of LK treatment, but the soluble protein content decreased. Quantitative proteomic analysis suggested that a total of 119 proteins were differentially abundant proteins (DAPs). KEGG analysis suggested that most represented DAPs were associated with secondary metabolism, the stress response, photosynthesis, protein synthesis, and degradation pathway. The proteomic results were verified using parallel reaction monitoring mass spectrometry (PRM-MS) analysis and quantitative real-time PCR (qRT-PCR)assays. Additional research suggested that overexpression of cationic peroxidase 1 of alligator weed (ApCPX1) in tobacco increased LK tolerance. The seed germination rate, peroxidase (POD) activity, and K+ content increased, and the hydrogen peroxide (H2O2) content decreased in the three transgenic tobacco lines after LK stress. The number of root hairs of the transgenic line was significantly higher than that of WT, and net K efflux rates were severely decreased in the transgenic line under LK stress. These results confirmed that ApCPX1 played positive roles in low-K+ signal sensing. These results provide valuable information on the adaptive mechanisms in leaves of alligator weed under LK stress and will help identify vital functional genes to apply to the molecular breeding of LK-tolerant plants in the future.

[Clinical Characteristics and Risk Factors of ESKAPE Pathogens Bloodstream Infection in Cancer Patients].

OBJECTIVE: To identify the risk factors of ESKAPE pathogens infection and related death in cancer patients, and to supply evidence for clinical precaution and diagnosis. METHODS: A retrospective study of clinical and experimental data of cancer patients with bloodstream infection were carried out in Sichuan Cancer Hospital from 2013 to 2018. The clinical feature, predisposing factors and risk factors of death in ESKAPE group and non-ESKAPE group were analyzed by univariate analysis and multivariate logistic regression. RESULTS: A total of 753 patients were enrolled in the study. Totally 795 pathogenic bacteria strains were isolated from blood culture and there were 278 ESKAPE strains, which took up 34.97% of isolated strains. Univariate analysis and multivariate logistic regression analysis showed that gender of male, multiple pathogens, history of exposure to enzyme inhibitors and agranulocytosis were independent risk factors of ESKAPE pathogens bloodstream infection. Peritoneal infection and combined fungal infection were independent risk factors of ESKAPE bloodstream infection related death. CONCLUSION: The bloodstream infection of ESKAPE pathogens is a problem worthy of clinical attention for cancer patients with neutrophil deficiency, previous antibiotic exposure, and fungal infection and peritoneal infection.

Physiological Analysis and Proteome Quantification of Alligator Weed Stems in Response to Potassium Deficiency Stress.

The macronutrient potassium is essential to plant growth, development and stress response. Alligator weed (Alternanthera philoxeroides) has a high tolerance to potassium deficiency (LK) stress. The stem is the primary organ responsible for transporting molecules from the underground root system to the aboveground parts of the plant. However, proteomic changes in response to LK stress are largely unknown in alligator weed stems. In this study, we investigated the physiological and proteomic changes in alligator weed stems under LK stress. First, the chlorophyll and soluble protein content and SOD and POD activity were significantly altered after 15 days of LK treatment. The quantitative proteomic analysis suggested that a total of 296 proteins were differentially abundant proteins (DAPs). The functional annotation analysis revealed that LK stress elicited complex proteomic alterations that were involved in oxidative phosphorylation, plant-pathogen interactions, glycolysis/gluconeogenesis, sugar metabolism, and transport in stems. The subcellular locations analysis suggested 104 proteins showed chloroplastic localization, 81 proteins showed cytoplasmic localization and 40 showed nuclear localization. The protein⁻protein interaction analysis revealed that 56 proteins were involved in the interaction network, including 9 proteins involved in the ribosome network and 9 in the oxidative phosphorylation network. Additionally, the expressed changes of 5 DAPs were similar between the proteomic quantification analysis and the PRM-MS analysis, and the expression levels of eight genes that encode DAPs were further verified using an RT-qPCR analysis. These results provide valuable information on the adaptive mechanisms in alligator weed stems under LK stress and facilitate the development of efficient strategies for genetically engineering potassium-tolerant crops.

Follistatin-like protein 1 induction of matrix metalloproteinase 1, 3 and 13 gene expression in rheumatoid arthritis synoviocytes requires MAPK, JAK/STAT3 and NF-κB pathways.

Elevated levels of follistatin-like protein 1 (FSTL1) have been found both in mouse models for human rheumatoid arthritis (RA) and collagen-induced arthritis (CIA). In this study, we elucidated the potential mechanisms by which FSTL1 contributes to the pathogenesis of RA. Fibroblast-like synoviocytes (FLSs) were established from synovial tissues of RA patients and stimulated with human recombinant FSTL1. Protein and mRNA expression levels of select matrix metalloproteinases (i.e., MMP1, MMP3, MMP13) in FLS were measured by, respectively, real-time RT-qPCR and ELISA. Activation of MAPK and other pathways that affect MMPs were evaluated by Western blotting. We also compared concentrations of MMPs in plasma in RA patients versus healthy controls (HC). Expression levels of MMP1, MMP3, and MMP13 were clearly stimulated by FSTL1 in vitro. FSTL1 activated the inflammation-related NF-κB signaling pathway, as well as all three mitogen-activated protein kinase (MAPK) pathways and the JAK/STAT3 pathway. Moreover, select chemical inhibitors that target p38 (SB203580), Erk1/2 (SP600125), JNK (SCH772984), STAT3 (AG490), and NF-κB (BAY 11-7082) significantly attenuated MMP expression. Inhibition of Toll-like receptor 4 by compound TAK-242 significantly abolished those effects of FSTL1. Importantly, elevated plasma concentrations of MMP3 were found to correlate with plasma FSTL1 levels in RA patients. These findings suggest that FSTL1 accelerates RA progression by activating MAPK, JAK/STAT3, and NF-κB pathways to enhance secretion of different MMPs and this enhancement is via TLR4. Targeting FSTL1 may provide a promising pharmacological drug therapy to ameliorate RA symptoms and perhaps reverse disease progression.

UBTD1 induces cellular senescence through an UBTD1-Mdm2/p53 positive feedback loop.

The tumour suppressor p53 plays an important role in tumourigenesis. Besides inducing apoptosis, it regulates cellular senescence, which constitutes an important barrier to tumourigenesis. The mechanism of regulation of cellular senescence by p53 and its downstream pathway are poorly understood. Here, we report that the ubiquitin domain-containing 1 (UBTD1) gene, a new downstream target of p53, induces cellular senescence and acts as a novel tumour suppressor by a mechanism that depends on p53. Expression of UBTD1 increased upon cellular senescence induced by serial passageing of cultures, as well as by exposure to DNA-damageing drugs that induce premature senescence. Over-expression of UBTD1 induces senescence in human fibroblasts and cancer cells and attenuation of the transformed phenotype in cancer cells. UBTD1 is down-regulated in gastric and colorectal cancer tissues, and its lower expression correlates with a more aggressive phenotype and worse prognosis. Multivariate analysis revealed that UBTD1 expression was an independent prognostic factor for gastric cancer patients. Furthermore, UBTD1 increased the stability of p53 protein, by promoting the degradation of Mdm2 protein. Importantly, UBTD1 and p53 function mutually depend on each other in regulating cellular senescence and proliferation. Thus, our data suggest that, upon DNA damage, p53 induction by UBTD1 creates a positive feedback mechanism to further increase p53 expression. Our results establish UBTD1 as a regulator of cellular senescence that mediates p53 function, and provide insights into the mechanism of Mdm2 inhibition that impacts p53 dynamics during cellular senescence and tumourigenesis.

Aggregatibacter Actinomycetemcomitans With Periodontitis and Rheumatoid Arthritis.

OBJECTIVE: The aim of this work was to explore the association between Aggregatibacter actinomycetemcomitans (A actinomycetemcomitans) infection and disease activity amongst those with rheumatoid arthritis (RA) with or without periodontitis (PD) in a Chinese population. METHODS: A case-control study was conducted from November 2017 to March 2019. The correlation coefficients between A actinomycetemcomitans positivity and RA-related examination indicators as well as periodontal examination parameters were calculated by using the Spearman correlation analysis. RESULTS: A total of 115 patients with RA were recruited: 67 patients with RA only and 48 with RA + PD. The percentage of A actinomycetemcomitans positivity was significantly higher in the RA + PD group compared with the RA-only group (P = .007 for positive percentage; P = .020 for percentage of A actinomycetemcomitans positivity in the total oral microbiome). Furthermore, RA-related measures such as Disease Activity Score 28, rheumatoid factor, anticyclic citrullinated peptide, and anticitrullinated protein antibodies were all positively correlated with the percentage of A actinomycetemcomitans positivity (P range: .002∼.041). In addition, significant correlations were observed amongst A actinomycetemcomitans positivity and probing pocket depth (P = .027) and gingival index (P = .043), whereas null correlations were found amongst the percentage of A actinomycetemcomitans positivity and plaque index (P = .344), clinical attachment loss (P = .217), and bleeding on probing (P = .710). CONCLUSIONS: A actinomycetemcomitans infection may be related to the development of PD amongst patients with RA.

Biomimetic Hydroxyapatite on 3D-Printed Nanoattapulgite/Polycaprolactone Scaffolds for Bone Regeneration of Rat Cranium Defects.

Nanoattapulgite (nano-ATP), a magnesium-aluminum silicate clay, can absorb substances and is a suitable material for bone repair and regeneration. In this study, using three-dimensional printing technology, a nano-ATP/polycaprolactone (PCL) scaffold was fabricated and modified using NaOH to form a rough surface. Biomimetic hydroxyapatite (HA) on nano-ATP/PCL scaffolds was fabricated using a biomineralized approach. The scaffold provided structural support through PCL and was modified with ATP and HA to improve hydrophilicity and promote the delivery of nutrients. The biocompatibility and osteogenic induction of scaffolds were assessed in vitro using mouse bone marrow mesenchymal stem cells. According to the in vitro study results, the nano-ATP/PCL/HA composite scaffold significantly boosted the expression levels of genes related to osteogenesis (p < 0.05), attributed to its superior alkaline phosphatase activity and calcium deposition capabilities. The outcomes of in vivo experimentation demonstrated an augmentation in bone growth at the rat cranial defect site when treated with the ATP/PCL/HA composite scaffold. It can be inferred from the results that the implementation of ATP and HA for the bone tissue engineering repair material displays encouraging prospects.

PPARγ regulates osteoarthritis chondrocytes apoptosis through caspase-3 dependent mitochondrial pathway.

Osteoarthritis (OA) is the most prevalent form of arthritis, characterized by a complex pathogenesis. One of the key factors contributing to its development is the apoptosis of chondrocytes triggered by oxidative stress. Involvement of peroxisome proliferator-activated receptor gamma (PPARγ) has been reported in the regulation of oxidative stress. However, there remains unclear mechanisms that through which PPARγ influences the pathogenesis of OA. The present study aims to delve into the role of PPARγ in chondrocytes apoptosis induced by oxidative stress in the context of OA. Primary human chondrocytes, both relatively normal and OA, were isolated and cultured for the following study. Various assessments were performed, including measurements of cell proliferation, viability and cytotoxicity. Additionally, we examined cell apoptosis, levels of reactive oxygen species (ROS), nitric oxide (NO), mitochondrial membrane potential (MMP) and cytochrome C release. We also evaluated the expression of related genes and proteins, such as collagen type II (Col2a1), aggrecan, inducible nitric oxide synthase (iNOS), caspase-9, caspase-3 and PPARγ. Compared with relatively normal cartilage, the expression of PPARγ in OA cartilage was down-regulated. The proliferation of OA chondrocytes decreased, accompanied by an increase in the apoptosis rate. Down-regulation of PPARγ expression in OA chondrocytes coincided with an up-regulation of iNOS expression, leading to increased secretion of NO, endogenous ROS production, and decrease of MMP levels. Furthermore, we observed the release of cytochrome C, elevated caspase-9 and caspase-3 activities, and reduction of the components of extracellular matrix (ECM) Col2a1 and aggrecan. Accordingly, utilization of GW1929 (PPARγ Agonists) or Z-DEVD-FMK (caspase-3 inhibitor) can protect chondrocytes from mitochondrial-related apoptosis and alleviate the progression of OA. During the progression of OA, excessive oxidative stress in chondrocytes leads to apoptosis and ECM degradation. Activation of PPARγ can postpone OA by down-regulating caspase-3-dependent mitochondrial apoptosis pathway.

Regulation of the immune microenvironment by pioglitazone-loaded polylactic glycolic acid nanosphere composite scaffolds to promote vascularization and bone regeneration.

Osteogenesis is caused by multiple factors, and the inflammatory response, osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), regeneration of blood vessels, and other factors must be considered in bone tissue engineering. To effectively repair bone defect, it is important to decrease excessive inflammation, enhance the differentiation of mesenchymal stem cells into osteoblasts, and stimulate angiogenesis. Herein, nano-attapulgite (ATP), polyvinyl alcohol (PVA), and gelatin (GEL) scaffolds were produced using 3D printing technology and pioglitazone (PIO)-containing polylactic acid-glycolic acid (PLGA) nanospheres were added. In both in vitro and in vivo studies, material scaffolds with PIO-loaded polylactic acid-glycolic acid nanospheres could reduce the inflammatory response by encouraging macrophage polarization from M1 to M2 and promoting the osteogenic differentiation of BMSCs by activating the BMP2/Smad/RUNX2 signal pathway to repair bone defects. The vascularization of human umbilical vein endothelial cells (HUVECs) through the PI3K/AKT/HIF1-/VEGF pathway was also encouraged. In vivo research using PIO-containing PLGA nanospheres revealed massive collagen deposition in skin models. These findings indicate a potentially effective scaffold for bone healing, when PLGA nanospheres-which contain the drug PIO-are combined with ATP/PVA/GEL scaffolds.

Acetyl zingerone ameliorates osteoarthritis by inhibiting chondrocyte programmed cell death.

Osteoarthritis (OA) is a degenerative disease that ultimately leads to joint deformity. The pathogenesis of OA is believed to involve abnormal chondrocyte death, with ferroptosis serving a key role in chondrocyte damage. The present study investigated whether acetyl zingerone (AZ), a newly identified antioxidant derived from curcumin, can alleviate the progression of OA. To investigate this, the present study performed various experiments, including crystal violet staining, flow cytometry, immunofluorescence and western blot analysis. In addition, dual validation was performed using in vivo and in vitro experiments; a mouse OA model was constructed for the in vivo experiments, and chondrocytes were used for the in vitro experiments. Destabilization of the medial meniscus (DMM) surgery was performed to establish an OA model in mice and IL­1ß was used to induce an OA model in vitro. The results indicated that AZ may promote chondrocyte viability and the expression of extracellular matrix components. Furthermore, AZ reduced the occurrence of ferroptosis by promoting the expression of glutathione peroxidase 4, inhibiting cartilage destruction and osteophyte formation, and alleviating damage to articular cartilage caused by DMM surgery. Mechanistically, the activation of nuclear factor erythroid 2­related factor 2 and heme oxygenase­1 may be responsible for the anti­ferroptosis effects of AZ on chondrocytes. These findings indicated that AZ may be considered a promising candidate for OA therapy.

Electrospun sandwich mesh structures loaded with naringenin and vitamin K2 polycaprolactone/gelatin nanofibers synergistically promote bone regeneration.

Osteoblasts and osteoclasts play a crucial role in the dynamically coupled balance during bone regeneration and remodeling. They complement and restrict each other in the human body. Decreased osteoblasts lead to insufficient bone formation or excessive formation of osteoclasts, leading to increased bone resorption, which will destroy the structure of the bone tissue. This will greatly increase the risk of diseases such as osteoporosis and nonunions caused by bone defects. Herein, gelatin and polycaprolactone were used as substrates, and biomaterial membranes with mesh and sandwich structures were constructed using the electrospinning technology. Naringenin was loaded into the shell, and vitamin K2 was loaded into the core layer of the nanofibrous membrane. The biocompatibility and osteogenic capacity of the membranes were assessed in vitro using mouse bone marrow mesenchymal stem cells (BMSCs). During osteoclast induction, the receptor activator of nuclear factor kappa-Β ligand (RANKL) was used to coculture RAW264.7 cells with various materials. The regulatory effect of various membranes on osteoclast growth was evaluated by detecting the expression levels of osteoclast-related genes and proteins in the cells. Subsequently, we constructed a model of a rat skull defect and implanted different membranes into the defect. Then, we evaluated the new bone formation in the defect using histological staining and micro-computed tomography after 4 and 8 weeks. The results of in vitro experiments confirmed that the incorporation of naringenin and vitamin K2 stimulated the expression of osteogenesis-related genes and the secretion of osteogenesis-related proteins. Simultaneously, the results showed that naringenin and vitamin K2 inhibited the formation and growth of osteoclasts. Therefore, naringenin and vitamin K2 have a synergistic effect in promoting bone growth and regulating osteoclast growth.

Fabrication of a three-dimensional printed gelatin/sodium alginate/nano-attapulgite composite polymer scaffold loaded with leonurine hydrochloride and its effects on osteogenesis and vascularization.

Bone tissue engineering scaffolds have made significant progress in treating bone defects in recent decades. However, the lack of a vascular network within the scaffold limits bone formation after implantation in vivo. Recent research suggests that leonurine hydrochloride (LH) can promote healing in full-thickness cutaneous wounds by increasing vessel formation and collagen deposition. Gelatin and Sodium Alginate are both polymers. ATP is a magnesium silicate chain mineral. In this study, a Gelatin/Sodium Alginate/Nano-Attapulgite composite hydrogel was used as the base material first, and the Gelatin/Sodium Alginate/Nano-Attapulgite composite polymer scaffold loaded with LH was then created using 3D printing technology. Finally, LH was grafted onto the base material by an amide reaction to construct a scaffold loaded with LH to achieve long-term LH release. When compared to pure polymer scaffolds, in vitro results showed that LH-loaded scaffolds promoted the differentiation of BMSCs into osteoblasts, as evidenced by increased expression of osteogenic key genes. The results of in vivo tissue staining revealed that the drug-loaded scaffold promoted both angiogenesis and bone formation. Collectively, these findings suggest that LH-loaded Gelatin/Sodium Alginate/Nano-Attapulgite composite hydrogel scaffolds are a potential therapeutic strategy and can assist bone regeneration.

Mg-HA-C/C Composites Promote Osteogenic Differentiation and Repair Bone Defects Through Inhibiting miR-16.

The hydroxyapatite (HA) coating on carbon/carbon (C/C) is reasonable and feasible to obtain bone graft materials with appropriate mechanical and biological properties. However, improvement of the physical and chemical properties of HA-C/C composites to promote bone regeneration and healing remains a challenge. In our present study, the HA coatings on C/C with magnesium (Mg) (Mg-HA-C/C) composites were synthesized that Ca (NO3)2, Mg (NO3)2, and NH4H2PO4 were mixed and coatings were made by electromagnetic induction deposition's heating. As determined with in vitro experiments, Mg-HA-C/C composites containing 10 and 20% Mg decreased miR-16 levels, increased cell viability, elevated the levels of osteogenesis-related genes, and promoted osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) seeded on their surfaces. In a rat model of skull defects, compared to the control group, at 4 and 12 weeks after the operation, the bone volume fraction (BV/TV) of Mg-HA-C/C composite group was increased by 8.439 ± 2.681% and 23.837 ± 7.845%, as well as the trabecular thickness (Tb.Th) was 56.247 ± 24.238 µm and 114.911 ± 34.015 µm more. These composites also increased the levels of ALP and RUNX2 in skull. The Mg-HA-C/C composite-enhanced bone regeneration and healing were blocked by in situ injection of an miR-16 mimic lentivirus vector. Thus, Mg-HA-C/C composites promote osteogenic differentiation and repair bone defects through inhibiting miR-16.