SAA1 increases NOX4/ROS production to promote LPS-induced inflammation in vascular smooth muscle cells through activating p38MAPK/NF-κB pathway

Formyl peptide receptor 2: a potential therapeutic target for inflammation-related diseases

Formyl peptide receptor 2 (FPR2) is a G protein-coupled receptor with seven transmembrane domains, widely distributed in human cells. It plays a crucial role in inflammation-related diseases. Known for its "double-edged sword" nature, FPR2 can bind a variety of exogenous and endogenous ligands, mediating both pro-inflammatory and anti-inflammatory responses in tissues such as eyes, liver, joints, lungs, nerves, and blood vessels. FPR2's bioactivities are regulated by a complex network of genes and signaling pathways. However, the precise regulatory mechanisms governing its functions in different inflammatory conditions are still not well understood. This review summarizes the FPR2's activities in various inflammation-related diseases and looks into its potential as a therapeutic target. This review highlights recent advances in developing exogenous agonists for FPR2 and discusses receptor expression across species to support nonclinical research. Overall, this review aims to clarify FPR2's role in inflammation and provide insights for the development of new drugs against inflammatory diseases.

Exploration of Hub Genes and Immune Cell Infiltration Characteristics Associated With Spinal Cord Injury in Mice

Background

Spinal cord injury (SCI) is a major disabling disease. However, the complex secondary injury mechanisms make the results of treatment unsatisfactory. This study aimed to screen for key biomarkers of SCI and explore immune cell infiltration to identify novel therapeutic targets for improving neurological recovery after the injury.

Methods

The SCI-associated gene microarray dataset was downloaded from GEO. The differential genes (DEGs) were first screened and analyzed according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment for DEGs biological functions and pathways, while the protein-protein interaction (PPI) network was established using STRING. Then, the Hub genes of SCI were mined by WGCNA and LASSO regression analysis. Finally, the level of infiltration of 24 immune cells was analyzed using the CIBERSORT method.

Results

A total of 522 DEGs were filtered. Enrichment analysis of their biological functions and pathways yielded the most closely related results for inflammatory response, regulation of cytokine production, neutrophil chemotaxis and degranulation, angiogenesis, cell death, TNF signaling pathway, and osteoclast differentiation. Four co-expression modules were obtained using WGCNA. Four Hub genes (2010004M13Rik, Cdkn1c, Nox4, and Gpr101) were obtained by analysis using the LASSO algorithm and validated by qRT-PCR. Finally, the infiltration of M0 and M2 macrophages, T Cells CD4 Follicular, and DC activated was assessed by immune infiltration analysis and was found to be associated with SCI.

Conclusion

2010004M13Rik, Cdkn1c, Nox4, and Gpr101 are Hub genes in SCI. Infiltration of M0, M2 macrophages, T Cells CD4 Follicular, and DC activated may also be associated with inflammation and neurological recovery after SCI.

Recent Advances in Studies of Serum Amyloid A: Implications in Inflammation, Immunity and Tumor Metastasis

Research on serum amyloid A (SAA) has seen major advancement in recent years with combined approaches of structural analysis and genetically altered mice. Initially identified as an acute-phase reactant, SAA is now recognized as a major player in host defense, inflammation, lipid metabolism and tumor metastasis. SAA binding and the neutralization of LPS attenuate sepsis in mouse models. SAA also displays immunomodulatory functions in Th17 differentiation and macrophage polarization, contributing to a pro-metastatic tumor microenvironment. In spite of the progress, the regulatory mechanisms for these diverse functions of SAA remain unclear. This review provides a brief summary of recent advances in SAA research on immunity, inflammation, tumor microenvironment and in vivo models.

LPS induces RGS-1 to promote infectious intracranial aneurysm formation and rupture by accelerating smooth muscle cell phenotypic switching

OBJECTIVE

Patients with infectious intracranial aneurysms (IIAs) have high mortality rates. Sepsis is an important condition that induces IIA. Smooth muscle cell (SMC) phenotypic switching may have a critical effect on sepsis-induced IIA, but its role remains unclear. Hence, we aimed to identify sepsis-induced target genes involved in SMC phenotypic switching and their underlying mechanisms.

METHODS AND RESULTS

RNA sequencing and bioinformatics analyses of samples from patients with intracranial aneurysms and sepsis identified RGS-1 as a common differentially expressed gene (DEG) involved in SMC phenotypic switching. Experimental verification demonstrated that lipopolysaccharide (LPS), a critical molecule in sepsis, increased RGS-1 levels, promoted SMC phenotypic switching and proliferation, and upregulated the expression of matrix metalloproteinases and inflammatory factors. Furthermore, qRT-PCR and immunofluorescence experiments confirmed that RGS-1 knockdown under LPS stimulation inhibited SMC phenotypic switching, cell proliferation, and decreases in matrix metalloproteinases and inflammatory factors. Mechanistically, western blotting, bioinformatics analyses, and chip assays revealed that RGS-1 activates the JNK-P38 pathway to promote SMC phenotypic switching and is regulated by the transcription factor STAT1.

CONCLUSION

LPS induces RGS-1 to promote IIA formation and rupture by accelerating SMC phenotypic switching.

Cyclic Nitroxide 4-Methoxy-Tempo May Decrease Serum Amyloid A-Mediated Renal Fibrosis and Reorganise Collagen Networks in Aortic Plaque

Acute-phase serum amyloid A (SAA) can disrupt vascular homeostasis and is elevated in subjects with diabetes, cardiovascular disease, and rheumatoid arthritis. Cyclic nitroxides (e.g., Tempo) are a class of piperidines that inhibit oxidative stress and inflammation. This study examined whether 4-methoxy-Tempo (4-MetT) inhibits SAA-mediated vascular and renal dysfunction. Acetylcholine-mediated vascular relaxation and aortic guanosine-3',5'-cyclic monophosphate (cGMP) levels both diminished in the presence of SAA. 4-MetT dose-dependently restored vascular function with corresponding increases in cGMP. Next, male ApoE-deficient mice were administered a vehicle (control, 100 µL PBS) or recombinant SAA (100 µL, 120 µg/mL) ± 4-MetT (at 15 mg/kg body weight via i.p. injection) with the nitroxide administered before (prophylaxis) or after (therapeutic) SAA. Kidney and hearts were harvested at 4 or 16 weeks post SAA administration. Renal inflammation increased 4 weeks after SAA treatment, as judged by the upregulation of IFN-γ and concomitant increases in iNOS, p38MAPK, and matrix metalloproteinase (MMP) activities and increased renal fibrosis (Picrosirius red staining) in the same kidneys. Aortic root lesions assessed at 16 weeks revealed that SAA enhanced lesion size (vs. control; p < 0.05), with plaque presenting with a diffuse fibrous cap (compared to the corresponding aortic root from control and 4-MetT groups). The extent of renal dysfunction and aortic lesion size was largely unchanged in 4-MetT-supplemented mice, although renal fibrosis diminished at 16 weeks, and aortic lesions presented with redistributed collagen networks. These outcomes indicate that SAA stimulates renal dysfunction through promoting the IFN-γ-iNOS-p38MAPK axis, manifesting as renal damage and enhanced atherosclerotic lesions, while supplementation with 4-MetT only affected some of these pathological changes.

The Chinese medicine Xin-tong-tai granule protects atherosclerosis by regulating oxidative stress through NOX/ROS/NF-κB signal pathway

BACKGROUND

Xin-tong-tai Granule (XTTG), a traditional Chinese medicine, has been used to treat atherosclerosis (AS), but its mechanism is poorly understood. Intriguingly, oxidative stress has been recognized as vital factors in the treatment of atherosclerosis.

PURPOSE

This study aims to explore the potential mechanism of XTTG for treating AS.

METHODS

An in-vivo model of AS was established by feeding ApoE-/- mice with a high-fat diet (HFD), and the Human Aortic Vascular Smooth Muscle Cells (HAVSMCs) were induced by oxidized low-density lipoprotein (ox-LDL) in vitro. After treatment, the blood lipid levels and pathological aortic changes of each group were observed, and the cell proliferation and lipid droplet aggregation in each group were evaluated. The oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) levels and related NOX/ROS/NF-κB signaling pathway indicators were observed.

RESULTS

XTTG improved blood lipid levels and pathological aortic changes of ApoE-/- mice with HFD feeding, inhibited HAVSMCs proliferation and lipid droplet aggregation induced by ox-LDL, reduced MDA content, increased SOD content, inhibited NOX4 and p22phox protein expression, downregulated ROS content, inhibited IKK-α, IKK-β, NF-κB protein and mRNA expression and the phosphorylation of NF-κB.

CONCLUSION

XTTG can inhibit NOX/ROS/NF-κB signaling pathway, reduce damages caused by oxidative stress, and exert anti-AS effects.

Anti-inflammatory therapy of atherosclerosis: focusing on IKKβ

Chronic low-grade inflammation has been identified as a major contributor in the development of atherosclerosis. Nuclear Factor-κappa B (NF-κB) is a critical transcription factors family of the inflammatory pathway. As a major catalytic subunit of the IKK complex, IκB kinase β (IKKβ) drives canonical activation of NF-κB and is implicated in the link between inflammation and atherosclerosis, making it a promising therapeutic target. Various natural product derivatives, extracts, and synthetic, show anti-atherogenic potential by inhibiting IKKβ-mediated inflammation. This review focuses on the latest knowledge and current research landscape surrounding anti-atherosclerotic drugs that inhibit IKKβ. There will be more opportunities to fully understand the complex functions of IKKβ in atherogenesis and develop new effective therapies in the future.

Gut Molecules in Cardiometabolic Diseases: The Mechanisms behind the Story

Atherosclerotic cardiovascular disease is the most common cause of morbidity and mortality worldwide. Diabetes mellitus increases cardiovascular risk. Heart failure and atrial fibrillation are associated comorbidities that share the main cardiovascular risk factors. The use of incretin-based therapies promoted the idea that activation of alternative signaling pathways is effective in reducing the risk of atherosclerosis and heart failure. Gut-derived molecules, gut hormones, and gut microbiota metabolites showed both positive and detrimental effects in cardiometabolic disorders. Although inflammation plays a key role in cardiometabolic disorders, additional intracellular signaling pathways are involved and could explain the observed effects. Revealing the involved molecular mechanisms could provide novel therapeutic strategies and a better understanding of the relationship between the gut, metabolic syndrome, and cardiovascular diseases.

Signaling Pathways in Inflammation and Cardiovascular Diseases: An Update of Therapeutic Strategies

Inflammatory processes represent a pivotal element in the development and complications of cardiovascular diseases (CVDs). Targeting these processes can lead to the alleviation of cardiomyocyte (CM) injury and the increase of reparative mechanisms. Loss of CMs from inflammation-associated cardiac diseases often results in heart failure (HF). Evidence of the crosstalk between nuclear factor-kappa B (NF-κB), Hippo, and mechanistic/mammalian target of rapamycin (mTOR) has been reported in manifold immune responses and cardiac pathologies. Since these signaling cascades regulate a broad array of biological tasks in diverse cell types, their misregulation is responsible for the pathogenesis of many cardiac and vascular disorders, including cardiomyopathies and atherosclerosis. In response to a myriad of proinflammatory cytokines, which induce reactive oxygen species (ROS) production, several molecular mechanisms are activated within the heart to inaugurate the structural remodeling of the organ. This review provides a global landscape of intricate protein–protein interaction (PPI) networks between key constituents of NF-κB, Hippo, and mTOR signaling pathways as quintessential targetable candidates for the therapy of cardiovascular and inflammation-related diseases.

Mouse Bone Marrow Mesenchymal Stem Cells Inhibit Sepsis-Induced Lung Injury in Mice via Exosomal SAA1

Sepsis is a global disease burden, and approximately 40% of cases develop acute lung injury (ALI). Bone marrow mesenchymal stromal cells (BMSCs) and their exosomes are widely used in treating a variety of diseases including sepsis. As an acute phase protein, serum amyloid A1 (SAA1) regulates inflammation and immunity. However, the role of SAA1 in BMSCs-exosomes in septic lung injury remains to be elucidated. Exosomes derived from serum and BMSCs were isolated by ultracentrifugation. SAA1 was silenced or overexpressed in mouse BMSCs using lentiviral plasmids, containing either SAA1-targeting short interfering RNAs or SAA1 cDNA. Sepsis was induced by cecal ligation and puncture (CLP). LPS was used to induce ALI in mice. Mouse alveolar macrophages were isolated by flow cytometry. Levels of SAA1, endotoxin, TNF-α, and IL-6 were measured using commercial kits. LPS internalization was monitored by immunostaining. RT-qPCR or immunoblots were performed to test gene and protein expressions. Serum exosomes of patients with sepsis-induced lung injury had significantly higher levels of SAA1, endotoxin, TNF-α, and IL-6. Overexpression of SAA1 in BMSCs inhibited CLP- or LPS-induced lung injury and decreased CLP- or LPS-induced endotoxin, TNF-α, and IL-6 levels. Administration of the SAA1 blocking peptide was found to partially inhibit SAA1-induced LPS internalization by mouse alveolar macrophages and reverse the protective effect of SAA1. In conclusion, BMSCs inhibit sepsis-induced lung injury through exosomal SAA1. These results highlight the importance of BMSCs, exosomes, and SAA1, which may provide novel directions for the treatment of septic lung injury.

Regulation of Atherosclerosis by Toll-Like Receptor 4 Induced by Serum Amyloid 1: A Systematic In Vitro Study

The objective of this study was to investigate the effects of serum amyloid 1 (SAA1) on activation of endothelial cells, formation of foam cells, platelet aggregation, and monocyte/platelet adhesion to endothelial cells. The effect of SAA1 on the inflammatory activation of endothelial cells was investigated by detecting the expression of inflammatory factors and adhesion molecules. The role of SAA1 in formation of foam cells was verified by detecting lipid deposition and expression of molecules related to the formation of foam cells. After platelets were stimulated by SAA1, the aggregation rate was evaluated to determine the effect of SAA1 on platelet aggregation. Monocytes/platelets were cocultured with human umbilical vein endothelial cells (HUVECs) pretreated with or without SAA1 to determine whether SAA1 affected monocyte/platelet adhesion to endothelial cells. By inhibiting toll-like receptor 4 (TLR4) function, we further identified the role of TLR4 signaling in SAA1-mediated endothelial inflammatory activation, foam-cell formation, and monocyte/platelet adhesion to HUVECs. SAA1 significantly increased the expression of adhesion molecules and inflammatory factors in HUVECs. Moreover, SAA1 also promoted lipid deposition and the expression of inflammatory factors and low-density lipoprotein receptor-1 (LOX-1) in THP-1-derived macrophages. In addition, SAA1 induced platelet aggregation and enhanced monocyte/platelet adhesion to HUVECs. However, the TLR4 antagonist significantly inhibited SAA1-induced endothelial cell activation, foam-cell formation, and monocyte/platelet adhesion to HUVECs and downregulated the expression of myeloid differentiation factor 88 (MyD88), phosphor-inhibitor of nuclear factor κB kinase subunit α/β (P-IKKα/β), phospho-inhibitor of nuclear factor κB subunit α (P-IKBα), and phosphorylation of nuclear transcription factor-κB p65 (P-p65) in SAA1-induced HUVECs and THP-1 cells. Conclusively, it is speculated that SAA1 promotes atherosclerosis through enhancing endothelial cell activation, platelet aggregation, foam-cell formation, and monocyte/platelet adhesion to endothelial cells. These biological functions of SAA1 may depend on the activation of TLR4-related nuclear factor-kappa B (NF-κB) signaling pathway.

Inhibiting vascular smooth muscle cell proliferation mediated by osteopontin via regulating gut microbial lipopolysaccharide: A novel mechanism for paeonol in atherosclerosis treatment

Background: Although the gut microbiota is involved in metabolic disease such as atherosclerosis, the underlying mechanism remains elusive. Paeonol (Pae) is a natural phenolic compound isolated from Cortex Moutan, which exhibits anti-atherosclerotic effects. Our previous research demonstrated gut microbiota as a site of Pae action. However, the mechanism by which Pae exerts its anti-atherosclerotic effect by the regulation of gut microbiota remains unclear.

Objective: To investigate a potential mechanistic link between the gut microbial lipopolysaccharide (LPS) and vascular smooth muscle cell (VSMC) proliferation in atherosclerosis progression and explore the possible role of Pae.

Methods: Experimental atherosclerosis was established in ApoE^−/− mice, and the atherosclerosis mice were treated with Pae for 4 weeks before being sacrificed for analyses while conducting fecal microbiota transplantation (FMT). The plaque area, levels of serum LPS, expressions of inflammatory factors in serum or aorta, and intestinal barrier permeability were determined. VSMCs were co-cultured with THP-1 cells. CCK-8 assay and EdU staining were performed to assess the proliferative capacity of VSMCs. Immunofluorescence staining was performed to observe the nuclear transfer of p65. Western blotting was used to detect the candidate protein expression level, and quantitative real-time PCR (qRT-PCR) was used to detect the mRNA expression level in tissues or cells of each group.

Results: During atherosclerosis progression, gut dysbiosis leads to the peripheral accumulation of gut microbial LPS, which acts as a trigger to stimulate osteopontin (OPN) production from circulating monocytes, inducing cell-to-cell crosstalk to promote VSMC proliferation in the aorta. Importantly, the elevation of LPS and OPN concentrations in the blood was also observed in patients with atherosclerosis. Pae could significantly improve atherosclerosis, suppress gut microbial LPS accumulation, and inhibit monocyte/macrophage activation and VSMC proliferation.

Conclusions: The present study provides a mechanistic scenario for how long-term stimulation of gut microbial LPS in circulating blood generates a pathological secondary response that leads to abnormal proliferation of VSMCs using high OPN expression in circulating monocytes and suggests a novel strategy for atherosclerosis therapy by remodeling the gut microbiota.

Activation of the Hepcidin-Ferroportin1 pathway in the brain and astrocytic-neuronal crosstalk to counteract iron dyshomeostasis during aging

During physiological aging, iron accumulates in the brain with a preferential distribution in regions that are more vulnerable to age-dependent neurodegeneration such as the cerebral cortex and hippocampus. In the brain of aged wild-type mice, alteration of the Brain Blood Barrier integrity, together with a marked inflammatory and oxidative state lead to increased permeability and deregulation of brain-iron homeostasis. In this context, we found that iron accumulation drives Hepcidin upregulation in the brain and the inhibition of the iron exporter Ferroportin1. We also observed the transcription and the increase of NCOA4 levels in the aged brain together with the increase of light-chain enriched ferritin heteropolymers, more efficient as iron chelators. Interestingly, in cerebral cortex and hippocampus, Ferroportin1 is mainly expressed by astrocytes, while the iron storage protein ferritin light-chain by neurons. This differential distribution suggests that astrocytes mediate iron shuttling in the nervous tissue and that neurons are unable to metabolize it. Our findings highlight for the first time that Hepcidin/Ferroportin1 axis and NCOA4 are directly involved in iron metabolism in mice brain during physiological aging as a response to a higher brain iron influx.

Protective effects of fraxin on cerebral ischemia-reperfusion injury by mediating neuroinflammation and oxidative stress through PPAR-γ/NF-κB pathway

BACKGROUND

Inflammation and oxidative stress are associated with the pathogenesis of cerebral ischemia-reperfusion (I/R) injury. Fraxin, one of the primary active ingredients of Cortex Fraxini, may have potent anti-inflammatory activity. This study intended to investigate the function and mechanism of fraxin in a middle cerebral artery occlusion (MCAO) model.

METHODS

A middle cerebral artery occlusion (MCAO) rat model was engineered. Both in-vivo and in-vitro models were dealt with Fraxin. The profiles of inflammation-concerned cytokines, proteins and oxidative stress factors were determined by RT-PCR, western blot, and enzyme-linked immunosorbent assay (ELISA), and neuronal apoptosis and reactive oxygen species (ROS) levels were measured. The neurological functions of rats were evaluated by Morris water maze and modified neurological severity scores (mNSS).

RESULTS

The data revealed that fraxin abated the OGD/R-mediated release of inflammatory and oxidative stress mediators, enhanced "M2″-like BV2 microglia polarization, and mitigated HT22 cell apoptosis. Mechanistically, fraxin boosted PPAR-γ expression, activated the Nrf2/HO-1 pathway, and suppressed NF-κB, IKK-β，p38 MAPK, ERK1/2 and Keap1 in a dose-dependent manner. Furthermore, attenuating PPAR-γ through pharmacological treatment with GW9662 (a PPAR-γ antagonist) mainly weakened the neuroprotective and anti-inflammatory functions of fraxin.

CONCLUSION

Fraxin could considerably ameliorate cerebral I/R damage by repressing oxidative stress, inflammatory response, and cell apoptosis through abrogating the PPARγ/ NF-κB pathway.

Ascorbic acid and hydrocortisone synergistically inhibit septic organ injury via improving oxidative stress and inhibiting inflammation

BACKGROUND

The current study aimed to investigate the effect of the combination of ascorbic acid (AscA) and hydrocortisone (Hyd) on septic organ injury and its potential mechanism.

METHOD

Sepsis was induced in mice by a single intraperitoneal injection of lipopolysaccharides.

RESULTS

AscA and Hyd combined showed more effective protection of the injured liver and kidney in septic mice by decreasing ALT, AST, BUN and SCr and ameliorating pathological manifestations than Hyd or AscA alone. AscA showed a mild inhibitory effect on the secretion of proinflammatory cytokines (TNF-α, IL-1β and IL-6). However, Hyd showed a weak regulatory effect on septic oxidative stress markers (MDA, SOD and GSH-Px). However, the combination of AscA and Hyd showed a more powerful inhibitory effect on the septic inflammatory response and oxidative stress than Hyd or AscA alone by decreasing TNF-α, IL-1β and IL-6 and regulating MDA, SOD and GSH. In an in vitro study, cotreatment of RAW 264.7 macrophages with Hyd and AscA sharply reduced reactive oxygen species (ROS) generation and synergistically inhibited TNF-α, IL-1β and IL-6 secretion, which could be abolished by additional stimulation with the ROS donor 3-nitropropionic acid (3-NP). As expected, cotreatment of macrophages with Hyd and AscA synergistically inhibited the activation of p38 MAPK and p-p65, and the effect could be reversed by additional stimulation with 3-NP.

CONCLUSIONS

AscA and Hyd synergistically protect the kidney and liver from injury by inhibiting the inflammatory response and oxidative stress. The powerful inhibitory effects of AscA on oxidative stress contribute to the synergistic anti-inflammatory action.

Fingolimod protects against cerebral ischemia reperfusion injury in rats by reducing inflammatory cytokines and inhibiting the activation of p38 MAPK and NF-κB signaling pathways

Fingolimod (FTY720) is a sphingosine 1-phosphate (S1P) receptor agonist. Here, to understand biological activity of FTY720 pretreatment and post-treatment on cerebral ischemia reperfusion injury (CIRI), rat transient middle cerebral artery occlusion/reperfusion (tMCAO/R) model was generated. Neurological deficit scoring was assessed after tMCAO/R. Four groups were established including sham-operated control group, operated group, and two FTY720-treated groups. Neuron damage was observed by Nissl staining. Gene expression was measured using qPCR and western blot analysis. Tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) levels were evaluated by enzyme-linked immunosorbent assay (ELISA). We uncovered that neurological score in two FTY720-treated groups was significantly lower than that in the operated group. FTY720 pretreatment or posttreatment groups had a significantly increased number of Nissl bodies in cerebral cortex as compared with the operated group, indicating that FTY720 administration reduced neuronal damage. Besides, FTY720 posttreatment improved memory impairment induced by tMCAO/R. In addition, IL-1β, IL-6, and TNF-α levels in the cerebral cortex and hippocampus of two FTY720-treated groups were significantly decreased in comparison to the operated group, showing that FTY720 could reduce the release of inflammatory cytokines in brain tissue. Furthermore, phosphorylation of p38MAPK and NF-κB pathway-related molecules in ischemic brain tissues of FTY720 group were markedly down-regulated compared to the operated group. Together, FTY720 pretreatment or posttreatment improved the neurological deficit of middle cerebral ischemia/reperfusion rat model and reduced neuronal damage by decreasing the levels of inflammatory cytokines and attenuating the phosphorylation levels of p38MAPK and NF-κB pathway-associated molecules. FTY720 exhibits neuroprotective effects against ischemic reperfusion injury in rats.

Anti-Inflammatory Effect of Auranofin on Palmitic Acid and LPS-Induced Inflammatory Response by Modulating TLR4 and NOX4-Mediated NF-κB Signaling Pathway in RAW264.7 Macrophages

Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.

Efficacy of the Piperidine Nitroxide 4-MethoxyTEMPO in Ameliorating Serum Amyloid A-Mediated Vascular Inflammation

Intracellular redox imbalance in endothelial cells (EC) can lead to endothelial dysfunction, which underpins cardiovascular diseases (CVD). The acute phase serum amyloid A (SAA) elicits inflammation through stimulating production of reactive oxygen species (ROS). The cyclic nitroxide 4-MethoxyTEMPO (4-MetT) is a superoxide dismutase mimetic that suppresses oxidant formation and inflammation. The aim of this study was to investigate whether 4-MetT inhibits SAA-mediated activation of cultured primary human aortic EC (HAEC). Co-incubating cells with 4-MetT inhibited SAA-mediated increases in adhesion molecules (VCAM-1, ICAM-1, E-selectin, and JAM-C). Pre-treatment of cells with 4-MetT mitigated SAA-mediated increases in transcriptionally activated NF-κB-p65 and P120 Catenin (a stabilizer of Cadherin expression). Mitochondrial respiration and ROS generation (mtROS) were adversely affected by SAA with decreased respiratory reserve capacity, elevated maximal respiration and proton leakage all characteristic of SAA-treated HAEC. This altered respiration manifested as a loss of mitochondrial membrane potential (confirmed by a decrease in TMRM fluorescence), and increased mtROS production as assessed with MitoSox Red. These SAA-linked impacts on mitochondria were mitigated by 4-MetT resulting in restoration of HAEC nitric oxide bioavailability as confirmed by assessing cyclic guanosine monophosphate (cGMP) levels. Thus, 4-MetT ameliorates SAA-mediated endothelial dysfunction through normalising EC redox homeostasis. Subject to further validation in in vivo settings; these outcomes suggest its potential as a therapeutic in the setting of cardiovascular pathologies where elevated SAA and endothelial dysfunction is linked to enhanced CVD.

Pro-Resolving FPR2 Agonists Regulate NADPH Oxidase-Dependent Phosphorylation of HSP27, OSR1, and MARCKS and Activation of the Respective Upstream Kinases

Background: Formyl peptide receptor 2 (FPR2) is involved in the pathogenesis of chronic inflammatory diseases, being activated either by pro-resolving or proinflammatory ligands. FPR2-associated signal transduction pathways result in phosphorylation of several proteins and in NADPH oxidase activation. We, herein, investigated molecular mechanisms underlying phosphorylation of heat shock protein 27 (HSP27), oxidative stress responsive kinase 1 (OSR1), and myristolated alanine-rich C-kinase substrate (MARCKS) elicited by the pro-resolving FPR2 agonists WKYMVm and annexin A1 (ANXA1). Methods: CaLu-6 cells or p22phox^Crispr/Cas9 double nickase CaLu-6 cells were incubated for 5 min with WKYMVm or ANXA1, in the presence or absence of NADPH oxidase inhibitors. Phosphorylation at specific serine residues of HSP27, OSR1, and MARCKS, as well as the respective upstream kinases activated by FPR2 stimulation was analysed. Results: Blockade of NADPH oxidase functions prevents WKYMVm- and ANXA1-induced HSP-27(Ser82), OSR1(Ser339) and MARCKS(Ser170) phosphorylation. Moreover, NADPH oxidase inhibitors prevent WKYMVm- and ANXA1-dependent activation of p38MAPK, PI3K and PKCδ, the kinases upstream to HSP-27, OSR1 and MARCKS, respectively. The same results were obtained in p22phox^Crispr/Cas9 cells. Conclusions: FPR2 shows an immunomodulatory role by regulating proinflammatory and anti-inflammatory activities and NADPH oxidase is a key regulator of inflammatory pathways. The activation of NADPH oxidase-dependent pro-resolving downstream signals suggests that FPR2 signalling and NADPH oxidase could represent novel targets for inflammation therapeutic intervention.

iTRAQ-Based Quantitative Proteomic Analysis of Intestines in Murine Polymicrobial Sepsis with Hydrogen Gas Treatment

Objective

Sepsis-associated intestinal injury has a higher morbidity and mortality in patients with sepsis, but there is still no effective treatment. Our research team has proven that inhaling 2% hydrogen gas (H₂) can effectively improve sepsis and related organ damage, but the specific molecular mechanism of its role is not clear. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics analysis was used for studying the effect of H₂ on intestinal injury in sepsis.

Methods

Male C57BL/6J mice were used to prepare a sepsis model by cecal ligation and puncture (CLP). The 7-day survival rates of mice were measured. 4-kd fluorescein isothiocyanate-conjugated Dextran (FITC-dextran) blood concentration measurement, combined with hematoxylin-eosinstain (HE) staining and Western blotting, was used to study the effect of H₂ on sepsis-related intestinal damage. iTRAQ-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used for studying the proteomics associated with H₂ for the treatment of intestinal injury.

Results

H₂ can significantly improve the 7-day survival rates of sepsis mice. The load of blood and peritoneal lavage bacteria was increased, and H₂ treatment can significantly reduce it. CLP mice had significant intestinal damage, and inhalation of 2% hydrogen could significantly reduce this damage. All 4194 proteins were quantified, of which 199 differentially expressed proteins were associated with the positive effect of H₂ on sepsis. Functional enrichment analysis indicated that H₂ may reduce intestinal injury in septic mice through the effects of thyroid hormone synthesis and nitrogen metabolism signaling pathway. Western blot showed that H₂ was reduced by down-regulating the expressions of deleted in malignant brain tumors 1 protein (DMBT1), insulin receptor substrate 2 (IRS2), N-myc downregulated gene 1 (NDRG1) and serum amyloid A-1 protein (SAA1) intestinal damage in sepsis mice.

Conclusion

A total of 199 differential proteins were related with H₂ in the intestinal protection of sepsis. H₂-related differential proteins were notably enriched in the following signaling pathways, including thyroid hormone synthesis signaling pathway, nitrogen metabolism signaling pathways, digestion and absorption signaling pathways (vitamins, proteins and fats). H₂ reduced intestinal injury in septic mice by down-regulating the expressions of SAA1, NDRG1, DMBT1 and IRS2.

The effect of nicotinamide adenine dinucleotide phosphate oxidase 4 on migration and invasion of fibroblast-like synoviocytes in rheumatoid arthritis

Background

Reactive oxygen species (ROS) regulate the migration and invasion of fibroblast-like synoviocytes (FLS), which are key effector cells in rheumatoid arthritis (RA) pathogenesis. Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) induces ROS generation and, consequently, enhances cell migration. Despite the important interrelationship between RA, FLS, and ROS, the effect of NOX4 on RA pathogenesis remains unclear.

Methods

FLS isolated from RA (n = 5) and osteoarthritis (OA, n = 5) patients were stimulated with recombinant interleukin 17 (IL-17; 10 ng/ml) and tumor necrosis factor alpha (TNF-α; 10 ng/ml) for 1 h. Cell migration, invasion, adhesion molecule expression, vascular endothelial growth factor (VEGF) secretion, and ROS expression were examined. The mRNA and protein levels of NOX4 were analyzed by RT-qPCR and western blotting, respectively. The NOX4 inhibitor GLX351322 and NOX4 siRNA were used to inhibit NOX4 to probe the effect of NOX4 on these cellular processes.

Results

Migration of RA FLS was increased 2.48-fold after stimulation with IL-17 and TNF-α, while no difference was observed for OA FLS. ROS expression increased in parallel with invasiveness of FLS following cytokine stimulation. When the expression of NOX was examined, NOX4 was significantly increased by 9.73-fold in RA FLS compared to unstimulated FLS. Following NOX4 inhibition, cytokine-induced vascular cell adhesion molecule 1 (VCAM1), VEGF, and migration and invasion capacity of RA FLS were markedly decreased to unstimulated levels.

Conclusion

NOX4 is a key contributor to cytokine-enhanced migration and invasion via modulation of ROS, VCAM1, and VEGF in RA FLS.

Pterostilbene prevents LPS-induced early pulmonary fibrosis by suppressing oxidative stress, inflammation and apoptosis in vivo

Early pulmonary fibrosis after acute lung injury leads to poor prognosis and high mortality. Pterostilbene (Pts), a bioactive component in blueberries, possesses anti-inflammatory, antioxidative and antifibrotic properties. However, the effects of Pts on lipopolysaccharide (LPS)-induced pulmonary fibrosis are still unknown. In our study, the Pts group showed lower lung injury and fibrosis scores, and lower levels of hydroxyproline and protein (collagen I and transforming growth factor-β) than the scores and levels in mice treated with LPS. MMP-1 was the degrading enzyme of collagen I and LPS caused the inhibition of MMP-1, disturbing the degradation of collagen. Additionally, Pts remarkably reversed the LPS-induced inhibition of interleukin-10 and the release of tumor necrosis factor-α, interleukin-6 and interleukin-1β. In terms of cellular pathways, Pts treatment ameliorated LPS-activated nuclear factor kappa B (NF-κB) and NOD-like receptor NLRP3 signaling. Besides, LPS-induced low levels of A20 could be activated by Pts. In addition, Pts treatment reversed the high levels of Caspase-3, poly ADP-ribose polymerase (PARP) and Bcl2-associated X protein (Bax) expression and the low levels of B cell lymphoma/lewkmia-2 (Bcl2) that had been induced by LPS. Moreover, oxidative stress is also involved in the pathogenesis of fibrosis. Our findings indicate that LPS injection triggered the production of myeloperoxidase (MPO) and malondialdehyde (MDA) and the depletion of superoxide dismutase (SOD) and glutathione (GSH), and that these effects were notably reversed by treatment with Pts. In addition, Pts induced the dissociation of Kelch-like epichlorohydrin-associated protein-1 (Keap-1) and NF-E2 related factor-2 (Nrf2) and the activation of downstream genes (heme oxygenase-1, NAD(P)H:quinine oxidoreductase, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier). In conclusion, oxidative stress, apoptosis and inflammation are involved in early pulmonary fibrosis and Pts exerts a protective effect by activating Keap-1/Nrf2, inhibiting caspase-dependent A20/NF-κB and NLRP3 signaling pathways.

Molecular mechanisms underlying zinc oxide nanoparticle induced insulin resistance in mice

Zinc oxide nanoparticles (ZnO NPs) represent an important class of commercially applied materials. Recently, adverse effects of ZnO NPs were found in humans and animals following ingestion, although the effects on endocrine system disease remain unclear. In this study, ZnO NPs were orally administered to mice, and at doses of 25 mg/kg bw (body weight) ZnO NPs and above, plasma glucose increased significantly. The genome-wide effects of ZnO NPs were then investigated using RNA-sequencing technology. In the cluster analysis, the most significantly enriched Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways concerned membranes and their close association with endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) generation. Biochemical and gene and protein expression analyses revealed that ZnO NPs activated a xenobiotic biodegradation response and increased the expression of cytochrome P450 (CYP) enzymes in mice livers, leading to ER stress. The ER stress increased ROS generation. The high levels of ROS activated the MAPK and NF-κB pathways and induced an inflammation response, resulting in the phosphorylation of insulin receptor substrate 1. Thus, the insulin resistance that developed was the primary mechanism for the increase in the plasma glucose of mice treated orally with ZnO NPs.