Oxidative stress stimulation leads to cell-specific oxidant and antioxidant responses in airway resident and inflammatory cells

Injectable carboxymethyl chitosan/oxidized dextran hydrogels containing zoledronic acid modified strontium hydroxyapatite nanoparticles

Nanocomposite hydrogels have potential in bone regeneration due to the inorganic and polymeric material content. In this study, new types of nanocomposite hydrogels composed of zoledronic acid/strontium hydroxyapatite nanoparticles and carboxymethyl chitosan/oxidized dextran (CMC/OD) hydrogels were reported. Pure hydroxyapatite, 5%, 10% and 15% (w/w) strontium-substituted strontium hydroxyapatite nanoparticles were produced and then modified with zoledronic acid at ratios of 5% to 7.5% (w/w). These modified structures were then incorporated into CMC/OD hydrogels. Zoledronic acid modified strontium hydroxyapatite nanoparticles were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). CMC/OD structures were investigated using Fourier Transform Infrared Analysis (FTIR), Scanning Electron Microscopy (SEM). The physical properties of the hydrogels were determined via degradation behavior and rheological measurements. Cell-material interactions were investigated in vitro. The results showed that the incorporation of hydroxyapatite nanoparticles into CMC would significantly improve the rheological properties. The addition of strontium to hydroxyapatite nanoparticles significantly enhanced cell proliferation. In addition, a significant increase in alkaline phosphatase (ALP) and calcium deposition was observed with the addition of zoledronic acid. In conclusion, the nanocomposite hydrogels of CMC/OD containing zoledronic acid modified strontium hydroxyapatite demonstrate potential for orthopedic and craniofacial applications due to their superior properties, including the ability to be easily injected into targeted areas, potent antibacterial activity that helps prevent infections and remarkable self-healing capabilities that promote tissue regeneration and repair.

Preparation and Characterization of Injectable Augmentation Gels Containing Polycaprolactone and Hyaluronic Acid

BACKGROUND

Injectable augmentation gels are widely used in the treatment of soft tissue. The composition of these gels has to be continuously improved due to the limitations of the currently available formulations.

AIMS

This study focuses on the development of an innovative injectable gel designed to address current trends and specific needs within the field.

METHODS

The current study utilized a safer hyaluronic acid (HA) gel carrier, created with a less toxic cross-linker, in combination with polycaprolactone (PCL) microspheres at various concentrations. PCL microspheres were prepared using an emulsification-solvent evaporation technique. Six different gel formulations were developed using PCL microspheres and biphasic HA gel structures.

RESULTS

The produced microspheres had non-agglomerated, smooth surfaces with an average particle size of approximately 45 ± 0.14 μm. The rheological results of the PCL-HA6 such as storage modulus (G', Pa), loss modulus (G", Pa), complex viscosity (η*), and phase angle (°) at 1 Hz frequency were measured as 553.97 ± 32.48, 368.4 ± 12.24, 105.9 ± 5.27, and 33.65 ± 0.92, respectively, and the injection force was measured as 9.64 ± 1.46. In vitro tests revealed that the PCL-HA6 group showed the highest cell viability compared to the other groups and provided a relative increase in collagen production over time, as demonstrated by the relevant gene expression.

CONCLUSIONS

The developed PCL/HA gel exhibited biocompatibility and non-toxicity, making it a safe option for soft tissue augmentation. It demonstrated potential for medical applications and exhibited favorable rheological characteristics and injectability.

HMOX1 as a potential drug target for upper and lower airway diseases: insights from multi-omics analysis

BACKGROUND

Oxidative stress is key in inflammatory airway diseases. Heme oxygenase 1 (HMOX1) regulates oxidative stress, but its role in airway diseases needs exploration.

METHODS

Differentially expressed genes (DEGs) between healthy nasal mucosa and chronic rhinosinusitis with nasal polyps (CRSwNP) were identified from Gene Expression Omnibus (GEO). Candidate genes were further screened using Gene Set Enrichment Analysis (GSEA) and Random Forest (RF) algorithms. Causal inference between candidate genes and upper and lower airway diseases (CRSwNP, allergic rhinitis (AR), and asthma (AS)) was conducted using bidirectional two-sample Mendelian randomization (TwoSampleMR) analysis. Single-cell RNA sequencing (scRNA-seq) data were used to determine the cellular localization and intercellular interactions of candidate genes. Molecular docking was used to identify potential therapeutic agents.

RESULTS

HMOX1 expression was significantly elevated in CRSwNP. TwoSampleMR analysis indicated a negative causal relationship between HMOX1 exposure and the occurrence of upper and lower airway diseases (CRSwNP [(odds ratio (OR)/95% confidence interval (CI): 0.945/(0.893-0.999), P = 0.044], AR [OR/95% CI: 0.997/(0.994-0.999), P = 0.007], and AS [OR/95% CI: 0.935/(0.895-0.977), P = 0.003]). scRNA-seq data revealed HMOX1 localization in M2 macrophages. Molecular docking identified 15 antioxidants, including Acetylcysteine and Quercetin, that can upregulate HMOX1 expression.

CONCLUSION

HMOX1 may have a protective role in the pathogenesis of upper and lower airway diseases (CRSwNP, AR, and AS) by modulating oxidative stress. Antioxidants that increase HMOX1 expression could offer new therapeutic avenues for these diseases.

CLINICAL TRIAL

Not applicable.

M2 macrophage derived HMOX1 defines chronic rhinosinusitis with nasal polyps

BACKGROUND

Molecular signatures of chronic rhinosinusitis with nasal polyps (CRSwNP) related to macrophages remain unclear. This study aimed to develop a macrophage-associated diagnostic signature for CRSwNP.

METHODS

Transcriptome data from 54 patients with CRSwNP and 37 healthy controls across GSE136825, GSE36830, and GSE72713 were used to identify differentially expressed genes (DEGs) between two groups. Gene Set Enrichment Analysis and Weighted Gene Co-Expression Network Analysis pinpointed crucial pathways and gene clusters. A diagnostic model was created from these analyses and receiver operating characteristic curve (ROC), and further validated in our transcriptome data from 29 samples. Immune cell infiltration analysis was performed and linked those diagnostic genes to macrophages and verified by single-cell RNA sequencing data. Immunofluorescence co-staining of CD163 and HMOX1 was performed in nasal tissues. Mouse bone marrow-derived macrophage (BMDMs) cultures were used in functional experiments. Correlations between the expression of HMOX1 and eotaxin genes were investigated.

RESULTS

DEGs of CRSwNP versus control group were enriched in the INTERLEUKIN_4_AND_13_SIGNALING pathways. A four-gene diagnostic model (HMOX1, ALOX5, F13A1 and ITGB2) was developed and demonstrated high diagnostic precision with an area under ROC curve of 0.980 for training dataset and 0.895 for test dataset. M2 macrophage presence and HMOX1 expression significantly correlated with CRSwNP (p < 0.001). Single-cell RNA sequencing data underscored the altered cellular composition in CRSwNP, with HMOX1 notably expressed in M2 macrophages. Immunofluorescence staining highlighted the increased infiltration of CD163+ M2 macrophages in nasal mucosa samples of eosinophilic CRSwNP, which correlated with HMOX1 protein levels (p < 0.05). The HMOX1 inhibitor zinc protoporphyrin reduced the ratio of CD163 + HMOX1 + M2 macrophages in mouse BMDM cultures (p < 0.05). HMOX1 expression showed a strong positive correlation with the expression of eotaxin genes (CCL11, CCL24, and CCL26; p < 0.05 respectively).

CONCLUSION

M2 macrophage-derived HMOX1 can be used as an innovative diagnostic signature for CRSwNP, which might be a potential regulator of eosinophilic inflammation.

E-cigarette vapor extract alters human eosinophil gene expression in an effect mediated by propylene glycol, glycerin, and nicotine

E-cigarette use has become widespread, and its effects on airway inflammation and disease are not fully delineated. E-cigarette vapor extract (EVE) profoundly affects neutrophil function. We hypothesized that EVE also alters eosinophil function and thus could impact allergic airway disease. We employed RNA sequencing to measure the ex vivo effect of EVE components on human eosinophil transcription. Blood eosinophils from 9 nonvaping subjects without asthma were isolated by negative selection. Cells were incubated for 48 h with EVE consisting of glycerin, propylene glycol, and nicotine (EVE+), EVE without nicotine ("EVE-"), air-exposed media termed extract buffer (EB), or untreated media. Bulk RNA sequencing was performed. Transcriptomic analysis revealed that the EB, EVE-, and EVE+ conditions showed highly variable gene expression with respect to no treatment and each other. Differential gene expression analysis comparing a combination of EVE+, EVE-, and EB revealed 3,030 differentially expressed genes (DEGs) with an adjusted P value <0.05 and log2 fold change >0.5 or <0.5. There were 645 DEGs between EB and EVE-, 1,713 between EB and EVE+, and 404 between EVE- and EVE+. Gene set enrichment analysis demonstrated that DEGs between both EVE+ and EVE- and the EB control were positively enriched for heme metabolism and apoptosis and negatively enriched tumor necrosis factor α signaling, interferon γ signaling, and inflammatory response. Thus, EVE significantly alters eosinophil metabolic and inflammatory pathways, mediated by propylene glycol and glycerin, with both enhancing and unique effects of nicotine. This study motivates further research into the pathogenic effects of vaping on airway eosinophils and allergic airways disease.

Hydrogen Gas Inhalation Alleviates Airway Inflammation and Oxidative Stress on Ovalbumin-Induced Asthmatic BALB/c Mouse Model

Airway inflammatory diseases, such as asthma, are a global public health concern owing to their chronic inflammatory effects on the respiratory mucosa. Molecular hydrogen (H2) has recently been recognized for its antioxidant and anti-inflammatory properties. In this study, we examined the therapeutic potential of H2 in airway inflammation using an ovalbumin (OVA)-induced BALB/c mouse model of allergic asthma. Female BALB/c mice were sensitized and challenged with OVA to induce airway inflammation, and 30 mice were randomly divided into five groups: NT (non-treatment), HTC (3% H2 treatment only), NC (negative control, OVA only), PC (positive control, OVA + intranasal 1 mg/mL salbutamol 50 μL), and HT (H2 treatment, OVA + inhaled 3% H2). Various inflammatory and oxidative stress (OS)-induced markers such as white blood cells (WBCs) and their differential counts, lung histology, cytokine levels such as interleukin (IL)-4, (IL)-5, (IL)-13, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), granulocyte-macrophage colony-stimulating factor (GM-CSF), (IL)-10, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT), and total immunoglobulin E (IgE) levels were investigated. Our results showed that inhaled H2 significantly reduced inflammatory cell infiltration, OS markers, and pro-inflammatory cytokine expression while upregulating antioxidant enzyme activity. Furthermore, H2 also significantly decreased serum IgE levels, a marker of allergic inflammation. Collectively, our findings suggest that H2 inhalation is a promising treatment option for airway inflammation, offering a novel approach with potential clinical applications.

Antidiabetic Effect of Bifidobacterium animalis TISTR 2591 in a Rat Model of Type 2 Diabetes

This study investigated the beneficial effects of probiotic Bifidobacterium animalis TISTR 2591 on the regulation of blood glucose and its possible mechanisms in a rat model of type 2 diabetes. The type 2 diabetic-Sprague Dawley rats were established by the combination of a high-fat diet and a low dose of streptozotocin. After 4 weeks of treatment with 2 × 108 CFU/ml of B. animalis TISTR 2591, fasting blood glucose (FBG), oral glucose tolerance, serum insulin, and pancreatic and hepatic histopathology were determined. Liver lipid accumulation, glycogen content, and gluconeogenic protein expression were evaluated. Oxidative stress and inflammatory status were determined. B. animalis TISTR 2591 significantly reduced FBG levels and improved glucose tolerance and serum insulin in the diabetic rats. Structural damage of the pancreas and liver was ameliorated in the B. animalis TISTR 2591-treated diabetic rats. In addition, significant decreases in hepatic fat accumulation, glycogen content, and phosphoenolpyruvate carboxykinase-1 protein expression were found in the diabetic rats treated with B. animalis TISTR 2591. The diabetic rats showed a significant reduction of inflammation following B. animalis TISTR 2591 supplementation, as demonstrated by decreasing hepatic NF-κB protein expression and serum and liver TNF-α levels. The B. animalis TISTR 2591 significantly decreased MDA levels and increased antioxidant SOD and GPx activities in the diabetic rats. In conclusion, B. animalis TISTR 2591 was shown to be effective in controlling glucose homeostasis and improving glucose tolerance in the diabetic rats. These beneficial activities were attributed to reducing oxidative and inflammatory status and modulating hepatic glucose metabolism.

Complement-Mediated Two-Step NETosis: Serum-Induced Complement Activation and Calcium Influx Generate NADPH Oxidase-Dependent NETs in Serum-Free Conditions

The complement system and neutrophils play crucial roles in innate immunity. Neutrophils release neutrophil extracellular traps (NETs), which are composed of decondensed DNA entangled with granular contents, as part of their innate immune function. Mechanisms governing complement-mediated NET formation remain unclear. In this study, we tested a two-step NETosis mechanism, as follows: classical complement-mediated neutrophil activation in serum and subsequent NET formation in serum-free conditions, using neutrophils from healthy donors, endothelial cells, and various assays (Fluo-4AM, DHR123, and SYTOX), along with flow cytometry and confocal microscopy. Our findings reveal that classical complement activation on neutrophils upregulated the membrane-anchored complement regulators CD46, CD55, and CD59. Additionally, complement activation increased CD11b on neutrophils, signifying activation and promoting their attachment to endothelial cells. Complement activation induced calcium influx and citrullination of histone 3 (CitH3) in neutrophils. However, CitH3 formation alone was insufficient for NET generation. Importantly, NET formation occurred only when neutrophils were in serum-free conditions. In such environments, neutrophils induced NADPH oxidase-dependent reactive oxygen species (ROS) production, leading to NET formation. Hence, we propose that complement-mediated NET formation involves a two-step process, as follows: complement deposition, neutrophil priming, calcium influx, CitH3 formation, and attachment to endothelial cells in serum. This is followed by NADPH-dependent ROS production and NET completion in serum-free conditions. Understanding this process may unveil treatment targets for pathologies involving complement activation and NET formation.

N-acetylcysteine as a potentially safe adjuvant in the treatment of neurotoxicity due to pirimiphos-methyl poisoning

Exogenous, well-established antioxidant N-acetylcysteine can reduce or prevent the deleterious effects of pesticides. In this study, utilizing a mouse model of daily single dose of N-acetylcysteine administration, we investigated the impact of this adjuvant on the treatment with atropine and/or obidoxime as well as oxidative stress response in pyrimiphos-methyl-induced toxicity. We found that N-acetylcysteine significantly reduces the oxidative stress generated by pyrimiphos-methyl. The therapy consisting of atropine and/or obidoxime routinely used in organophosphorous insecticide poisonings, including pyrimiphos-methyl, had no effect on the antioxidant properties of N-acetylcysteine. Adjunctive treatment offered by N-acetylcysteine fills therapeutic gap and may provide the full potential against pyrimiphos-methyl-induced toxicity.

IL-4 activates ULK1/Atg9a/Rab9 in asthma, NLRP3 inflammasomes, and Golgi fragmentation by increasing autophagy flux and mitochondrial oxidative stress

During asthma, there is an intensification of pulmonary epithelial inflammation, mitochondrial oxidative stress, and Golgi apparatus fragmentation. However, the underlying mechanism remains largely unknown. Therefore, this study investigated the roles of ULK1, Atg9a, and Rab9 in epithelial inflammation, mitochondrial oxidative stress, and Golgi apparatus fragmentation. We found that ULK1 gene knockout reduced the infiltration of inflammatory cells, restored the imbalance of the Th1/Th2 ratio, and inhibited the formation of inflammatory bodies in the lung tissue of house dust mite-induced asthma mice. Moreover, we demonstrated that Atg9a interacted with ULK1 at S467. ULK1 phosphorylated Atg9a at S14. Treatment with ULK1 activator (LYN-1604) and ULK1 inhibitor (ULK-101) respectively promoted and inhibited inflammasome activation, indicating that the activation of inflammasome induced by house dust mite in asthma mice is dependent on ULK1. For validation of the in vivo results, we then used a lentivirus containing ULK1 wild type and ULK1-S467A genes to infect Beas-2b-ULK1-knockout cells and establish a stable cell line. The results suggest that the ULK1 S467 site is crucial for IL-4-induced inflammation and oxidative stress. Experimental verification confirmed that Atg9a was the superior signaling pathway of Rab9. Interestingly, we found for the first time that Rab9 played a very important role in inflammation-induced fragmentation of the Golgi apparatus. Inhibiting the activation of the ULK1/Atg9a/Rab9 signaling pathways can inhibit Golgi apparatus fragmentation and mitochondrial oxidative stress in asthma while reducing the production of NLRP3-mediated pulmonary epithelial inflammation.

A deep insight into ferroptosis in lung disease: facts and perspectives

In the last decade, ferroptosis has received much attention from the scientific research community. It differs from other modes of cell death at the morphological, biochemical, and genetic levels. Ferroptosis is mainly characterized by non-apoptotic iron-dependent cell death caused by iron-dependent lipid peroxide excess and is accompanied by abnormal iron metabolism and oxidative stress. In recent years, more and more studies have shown that ferroptosis is closely related to the occurrence and development of lung diseases. COPD, asthma, lung injury, lung fibrosis, lung cancer, lung infection and other respiratory diseases have become the third most common chronic diseases worldwide, bringing serious economic and psychological burden to people around the world. However, the exact mechanism by which ferroptosis is involved in the development and progression of lung diseases has not been fully revealed. In this manuscript, we describe the mechanism of ferroptosis, targeting of ferroptosis related signaling pathways and proteins, summarize the relationship between ferroptosis and respiratory diseases, and explore the intervention and targeted therapy of ferroptosis for respiratory diseases.

Effects of Acetyl-L-Carnitine on Oxidative Stress in Amyotrophic Lateral Sclerosis Patients: Evaluation on Plasma Markers and Members of the Neurovascular Unit

Oxidative stress, the alteration of mitochondrial function, and the neurovascular unit (NVU), play a role in Amyotrophic Lateral Sclerosis (ALS) pathogenesis. We aimed to demonstrate the changes in the plasma redox system and nitric oxide (NO) in 32 new ALS-diagnosed patients in treatment with Acetyl-L-Carnitine (ALCAR) compared to healthy controls. We also evaluated the effects of plasma on human umbilical cord-derived endothelial vascular cells (HUVEC) and astrocytes. The analyses were performed at the baseline (T0), after three months (T1), and after six months (T2). In ALS patients at T0/T1, the plasma markers of lipid peroxidation, thiobarbituric acid reactive substances (TBARS) and 4-hydroxy nonenal (4-HNE) were higher, whereas the antioxidants, glutathione (GSH) and the glutathione peroxidase (GPx) activity were lower than in healthy controls. At T2, plasma TBARS and 4-HNE decreased, whereas plasma GSH and the GPx activity increased in ALS patients. As regards NO, the plasma levels were firmly lower at T0-T2 than those of healthy controls. Cell viability, and mitochondrial membrane potential in HUVEC/astrocytes treated with the plasma of ALS patients at T0-T2 were reduced, while the oxidant release increased. Those results, which confirmed the fundamental role of oxidative stress, mitochondrial function, and of the NVU in ALS pathogenesis, can have a double meaning, acting as disease markers at baseline and potential markers of drug effects in clinical practice and during clinical trials.

Serum response factor activates peroxidasin transcription to block senescence of hepatic stellate cells

AIMS

Aberrant liver fibrosis is a hallmark event in end-stage liver diseases. Hepatic stellate cells (HSCs) are considered the major source of myofibroblasts in the liver that produce extracellular matrix proteins to promote liver fibrosis. HSCs undergo senescence in response to various stimuli, a process that can be exploited to dampen liver fibrosis. We investigated the role of serum response factor (SRF) in this process.

METHODS AND MATERIALS

Senescence was induced HSCs by serum withdrawal or progressive passage. DNA-protein interaction was evaluated by chromatin immunoprecipitation (ChIP).

RESULTS

SRF expression was down-regulated in HSCs entering into senescence. Coincidently, SRF depletion by RNAi accelerated HSC senescence. Of note, treatment of an anti-oxidant (N-acetylcysteine or NAC) blocked HSC senescence by SRF deficiency suggesting that SRF may antagonize HSC senescence by eliminating excessive reactive oxygen species (ROS). PCR-array based screening identified peroxidasin (PXDN) as a potential target for SRF in HSCs. PXDN expression was inversely correlated with HSC senescence whereas PXDN knockdown accelerated HSC senescence. Further analysis reveals that SRF directly bound to the PXDN promoter and activated PXDN transcription. Consistently, PXDN over-expression protected whereas PXDN depletion amplified HSC senescence. Finally, PXDN knockout mice displayed diminished liver fibrosis compared to wild type mice when subjected to bile duct ligation (BDL).

SIGNIFICANCE

Our data suggest that SRF, via its downstream target PXDN, plays a key role in regulating HSC senescence.