IL-1beta augments TNF-alpha-mediated inflammatory responses from lung epithelial cells

Effects of lysine deacetylase inhibitor treatment on LPS responses of alveolar-like macrophages

Macrophages are key immune cells that can adapt their metabolic phenotype in response to different stimuli. Lysine deacetylases are important enzymes regulating inflammatory gene expression and lysine deacetylase inhibitors have been shown to exert anti-inflammatory effects in models of chronic obstructive pulmonary disease. We hypothesized that these anti-inflammatory effects may be associated with metabolic changes in macrophages. To validate this hypothesis, we used an unbiased and a targeted proteomic approach to investigate metabolic enzymes, as well as liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry, to quantify metabolites in combination with the measurement of functional parameters in primary murine alveolar-like macrophages after lipopolysaccharide-induced activation in the presence or absence of lysine deacetylase inhibition. We found that lysine deacetylase inhibition resulted in reduced production of inflammatory mediators such as tumor necrosis factor α and interleukin 1β. However, only minor changes in macrophage metabolism were observed, as only one of the lysine deacetylase inhibitors slightly increased mitochondrial respiration while no changes in metabolite levels were seen. However, lysine deacetylase inhibition specifically enhanced expression of proteins involved in ubiquitination, which may be a driver of the anti-inflammatory effects of lysine deacetylase inhibitors. Our data illustrate that a multiomics approach provides novel insights into how macrophages interact with cues from their environment. More detailed studies investigating ubiquitination as a potential driver of lysine deacetylase inhibition will help developing novel anti-inflammatory drugs for difficult-to-treat diseases such as chronic obstructive pulmonary disease.

Prolactin Inhibits or Stimulates the Inflammatory Response of Joint Tissues in a Cytokine-dependent Manner

The close association between rheumatoid arthritis (RA), sex, reproductive state, and stress has long linked prolactin (PRL) to disease progression. PRL has both proinflammatory and anti-inflammatory outcomes in RA, but responsible mechanisms are not understood. Here, we show that PRL modifies in an opposite manner the proinflammatory actions of IL-1β and TNF-α in mouse synovial fibroblasts in culture. Both IL-1β and TNF-α upregulated the metabolic activity and the expression of proinflammatory factors (Il1b, Inos, and Il6) via the activation of the nuclear factor-κB (NF-κB) signaling pathway. However, IL-1β increased and TNF-α decreased the levels of the long PRL receptor isoform in association with dual actions of PRL on synovial fibroblast inflammatory response. PRL reduced the proinflammatory effect and activation of NF-κB by IL-1β but increased TNF-α-induced inflammation and NF-κB signaling. The double-faceted role of PRL against the 2 cytokines manifested also in vivo. IL-1β or TNF-α with or without PRL were injected into the knee joints of healthy mice, and joint inflammation was monitored after 24 hours. IL-1β and TNF-α increased the joint expression of proinflammatory factors and the infiltration of immune cells. PRL prevented the actions of IL-1β but was either inactive or further increased the proinflammatory effect of TNF-α. We conclude that PRL exerts opposite actions on joint inflammation in males and females that depend on specific proinflammatory cytokines, the level of the PRL receptor, and the activation of NF-κB signaling. Dual actions of PRL may help balance joint inflammation in RA and provide insights for development of new treatments.

Early innate immune responses in European sea bass (Dicentrarchus labrax L.) following Tenacibaculum maritimum infection

Introduction

The marine aquaculture industry has been witnessing a worldwide emergence of tenacibaculosis, a poorly understood bacterial disease caused by Tenacibaculum maritimum that affects commercially important fish. So far, knowledge on the T. maritimum virulence mechanisms is scarce and the pathogen-host interaction operating in tenacibaculosis remain to be disclosed. This study aimed at contributing to a better understanding of this disease, by evaluating the early innate immune response triggered in European sea bass (Dicentrarchus labrax) by a bath-challenge with T. maritimum.

Methods

Groups of sea bass were bath-challenged with T. maritimum (challenged fish) or mock-challenged. Undisturbed fish were used as controls (time 0). Samples of blood, liver and mucosal organs (skin, gills and posterior-intestine) were collected at 0 h (control) and at 6, 24, 48 and 72 h post-challenge (n=12). Mucosal organs were used for analyzing the expression of immune-related genes by RT-qPCR, as well as blood samples for assessing haematological and innate humoral parameters and liver for oxidative stress assessment.

Results

An increased expression of il-1β, il8, mmp9 and hamp1 was detected in all mucosal organs of infected fish when compared with control and mock-challenged fish, suggesting a pro-inflammatory response against T. maritimum transversal to all organs. The faster induction of these pro-inflammatory genes was observed in the gills. Regarding the systemic response, challenged fish presented neutrophilia, monocytosis, signs of anemia, and a decrease of bactericidal and lysozyme activities in plasma. Almost no variations were observed regarding hepatic oxidative stress.

Discussion/Conclusions

The present study suggests that T. maritimum induces a local innate immune response upon bath infection not only in the skin of European sea bass, but also in the gills and posterior-intestine, likely triggered by the T. maritimum's capacity to adhere, colonize and damage these organs that can function as entry ways to bacteria, leading ultimately to the seen host's systemic response.

Evaluation of the innate immune response of caprine neutrophils against Mycobacterium avium subspecies paratuberculosis in vitro

Neutrophils constitute an essential component of the innate immune response, readily killing most bacteria through phagocytosis, degranulation, and the release of neutrophil extracellular traps (NETs) among other mechanisms. These cells play an unclear role in mycobacterial infections such as Mycobacterium avium subspecies paratuberculosis (Map), the etiological agent of paratuberculosis, and its response is particularly understudied in ruminants. Herein, a wide set of techniques were adapted, or newly developed, to study the in vitro response of caprine neutrophils after Map infection. Immunofluorescence was used to demonstrate, simultaneously, chemotaxis, phagocytosis, degranulation, and NETs. The quantification of neutrophil phagocytic activity against Map at a 1:10 multiplicity of infection (MOI), through flow cytometry, showed values that varied from 4.54 to 5.63% of phagocyting neutrophils. By immunofluorescence, a 73.3 ± 14.5% of the fields showed NETs, and the mean release of DNA, attributable to NETosis, calculated through a fluorometric method, was 16.2 ± 3.5%. In addition, the RNA expression of TGF-β, TNF and IL-1β cytokines, measured through reverse transcription qPCR, was significantly higher in the two latter. Overall, neutrophil response was proportional to the number of bacteria. This work confirms that the simultaneous study of several neutrophil mechanisms, and the combination of different methodologies, are essential to reach a comprehensive understanding of neutrophil response against pathogens, demonstrates that, in vitro, caprine neutrophils display a strong innate response against Map, using their entire repertoire of effector functions, and sets the basis for further in vitro and in vivo studies on the role of neutrophils in paratuberculosis.

Is There a Similarity in Serum Cytokine Profile between Patients with Periodontitis or 2019-Novel Coronavirus Infection?—A Scoping Review

On 11 March 2020, the WHO declared a global emergency as a result of the ‘novel coronavirus infection’, which emerged from Wuhan, China, and rapidly spread across international borders. There is vast evidence that supports a direct link between oral cavities and this systemic circulation, but it is still unclear if oral conditions like periodontitis influenced the COVID-19 disease outcome. This scoping review highlights the fact that both periodontitis and COVID-19 independently increase serum pro-inflammatory cytokine levels, however there is a lack of documentation on if this biochemical profile synergizes with COVID-19 and/or periodontal severity in the same individuals. The purpose of this scoping review is to accumulate existing data on the serums IL-1β, IL-6, and TNF-α in COVID-19 and periodontitis patients and check if periodontitis negatively impacts the COVID-19 outcome, educating the population about the implications of COVID-19-related complications on their oral health, and vice versa, and motivating patients towards oral hygiene maintenance.

The Role of Tocotrienol in Arthritis Management—A Scoping Review of Literature

Arthritis is a cluster of diseases impacting joint health and causing immobility and morbidity in the elderly. Among the various forms of arthritis, osteoarthritis (OA) and rheumatoid arthritis (RA) are the most common. Currently, satisfying disease-modifying agents for arthritis are not available. Given the pro-inflammatory and oxidative stress components in the pathogenesis of arthritis, tocotrienol, a family of vitamin E with both anti-inflammatory and antioxidant properties, could be joint-protective agents. This scoping review aims to provide an overview of the effects of tocotrienol on arthritis derived from the existing scientific literature. A literature search using PubMed, Scopus and Web of Science databases was conducted to identify relevant studies. Only cell culture, animal and clinical studies with primary data that align with the objective of this review were considered. The literature search uncovered eight studies investigating the effects of tocotrienol on OA (n = 4) and RA (n = 4). Most of the studies were preclinical and revealed the positive effects of tocotrienol in preserving joint structure (cartilage and bone) in models of arthritis. In particular, tocotrienol activates the self-repair mechanism of chondrocytes exposed to assaults and attenuates osteoclastogenesis associated with RA. Tocotrienol also demonstrated strong anti-inflammatory effects in RA models. The single clinical trial available in the literature showcases that palm tocotrienol could improve joint function among patients with OA. In conclusion, tocotrienol could be a potential anti-arthritic agent pending more results from clinical studies.

Cdc42 regulates cytokine expression and trafficking in bronchial epithelial cells

Airway epithelial cells can respond to incoming pathogens, allergens and stimulants through the secretion of cytokines and chemokines. These pro-inflammatory mediators activate inflammatory signaling cascades that allow a robust immune response to be mounted. However, uncontrolled production and release of cytokines and chemokines can result in chronic inflammation and appears to be an underlying mechanism for the pathogenesis of pulmonary disorders such as asthma and COPD. The Rho GTPase, Cdc42, is an important signaling molecule that we hypothesize can regulate cytokine production and release from epithelial cells. We treated BEAS-2B lung epithelial cells with a set of stimulants to activate inflammatory pathways and cytokine release. The production, trafficking and secretion of cytokines were assessed when Cdc42 was pharmacologically inhibited with ML141 drug or silenced with lentiviral-mediated shRNA knockdown. We found that Cdc42 inhibition with ML141 differentially affected gene expression of a subset of cytokines; transcription of IL-6 and IL-8 were increased while MCP-1 was decreased. However, Cdc42 inhibition or depletion disrupted IL-8 trafficking and reduced its secretion even though transcription was increased. Cytokines transiting through the Golgi were particularly affected by Cdc42 disruption. Our results define a role for Cdc42 in the regulation of cytokine production and release in airway epithelial cells. This underscores the role of Cdc42 in coupling receptor activation to downstream gene expression and also as a regulator of cytokine secretory pathways.

Consequences of the Lack of TNFR1 in Ouabain Response in the Hippocampus of C57BL/6J Mice

Ouabain is a cardiac glycoside that has a protective effect against neuroinflammation at low doses through Na⁺/K⁺-ATPase signaling and that can activate tumor necrosis factor (TNF) in the brain. TNF plays an essential role in neuroinflammation and regulates glutamate receptors by acting on two different receptors (tumor necrosis factor receptor 1 [TNFR1] and TNFR2) that have distinct functions and expression. The activation of constitutively and ubiquitously expressed TNFR1 leads to the expression of pro-inflammatory cytokines. Thus, this study aimed to elucidate the effects of ouabain in a TNFR1 knockout (KO) mouse model. Interestingly, the hippocampus of TNFR1 KO mice showed a basal increase in both TNFR2 membrane expression and brain-derived neurotrophic factor (BDNF) release, suggesting a compensatory mechanism. Moreover, ouabain activated TNF-α-converting enzyme/a disintegrin and metalloprotease 17 (TACE/ADAM17), decreased N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression, and induced anxiety-like behavior in both genotype animals, independent of the presence of TNFR1. However, ouabain induced an increase in interleukin (IL)-1β in the hippocampus, a decrease in IL-6 in serum, and an increase in NMDA receptor subunit 1 (NR1) only in wild-type (WT) mice, indicating that TNFR1 or TNFR2 expression may be important for some effects of ouabain. Collectively, our results indicate a connection between ouabain signaling and TNFR1, with the effect of ouabain partially dependent on TNFR1.

The in vitro anti-inflammatory activity of N-antipyrine-3,4-dichloromaleimide derivatives is due to an immunomodulatory effect on cytokines environment

BACKGROUND AND AIM

Inflammation is the immune response to a harmful stimulus, and its purpose is to destroy foreign agents so that the affected site can be repair. When uncontrolled or unresolved, inflammation can lead to significant tissue damage. Many classes of compounds are used today as anti-inflammatory drugs. However, there is an ongoing demand for new, more effective molecules with higher safety margins. In this regard, the anti-inflammatory effect of six synthetic compounds of N-antipyrine-3,4-dichloromaleimide was evaluated.

METHODS

RAW 264.7 cells were used to evaluate the cytotoxicity and the anti-inflammatory activity, by measuring the effect of these molecules on nitric oxide, IL-1β, IL-6, MCP-1 (CCL2), TNF-α, INF-γ, IL-4, and IL-13 levels, as well as under NF-κB activation.

RESULTS

Some of the tested compounds showed significant cytotoxicity (CC50 < 100 µM). Subsequently, the potential of nitric oxide (NO) inhibition as screening for potential anti-inflammatory action was evaluated. Three of the compounds tested showed a promising profile (1, 3, and 5). When the effect of these compounds was evaluated on the production of IL-1β, IL-6, MCP-1 (CCL2), TNF-α, and INF-γ, only N-antipyrine-3,4-dichloromaleimide (1) and N-antipyrine-3-chloro-4-(3,4-dichloroaniline) maleimide (3) showed significant inhibition profiles. These two compounds were also able to increase the production of cytokines known for having an anti-inflammatory profile (IL-4 and IL-13) and inhibit the phosphorylation of the p-p65 NF-κB subunit significantly.

CONCLUSION

In conclusion, these two compounds present a significant and unusual anti-inflammatory mechanism (increasing the production of anti-inflammatory mediators). They are therefore considered promising prototypes for the development of new anti-inflammatory drugs with immunomodulatory characteristics.

Lactobacillus mucosae exerted different antiviral effects on respiratory syncytial virus infection in mice

Respiratory syncytial virus (RSV) infection is a constant threat to the health of young children, and this is mainly attributed to the lack of effective prevention strategies. This study aimed to determine whether Lactobacillus (L.) mucosae, a potential probiotic, could protect against respiratory viral infection in a mouse model. Naive 3–4-week-old BALB/c mice were orally administered with three L. mucosae strains (2.5 × 10⁸ CFU/mouse) 7 days before RSV infection (10⁵ TCID₅₀/mouse). Results showed that all three strains inhibited RSV replication and reduced the proportions of inflammatory cells, including granulocytes and monocytes in the blood. The L. mucosae M104R01L3 treatment maintained stable weight in mice and increased interferon (IFN)-β and tumor necrosis factor (TNF)-α levels. The L. mucosae DCC1HL5 treatment increased interleukin (IL)-1β and IL-10 levels. Moreover, the M104R01L3 and DCC1HL5 strains increased the proportions of Akkermansia, Alistipes, and Anaeroplasma which contributed to the advantageous modulation of the gut microbiota. Besides, L. mucosae affected the gut levels of short-chain fatty acids (SCFAs) that are important for the antiviral response. L. mucosae 1,025 increased acetate, propionate, and butyrate levels, whereas L. mucosae M104R01L3 increased the level of acetate in the gut. L. mucosae M104R01L3 may protect against viral infection by upregulating the IFN-β levels in the lungs and its antiviral effect may be related to the increase of acetate levels in the gut. In conclusion, the three L. mucosae strains exerted antiviral effects against RSV infection by differentially regulating immune responses and intestinal micro-ecological balance. This study can provide a reference for studying the mechanisms underlying the antiviral effects of L. mucosae.

Dichotomous Role of Tumor Necrosis Factor in Pulmonary Barrier Function and Alveolar Fluid Clearance

Alveolar-capillary leak is a hallmark of the acute respiratory distress syndrome (ARDS), a potentially lethal complication of severe sepsis, trauma and pneumonia, including COVID-19. Apart from barrier dysfunction, ARDS is characterized by hyper-inflammation and impaired alveolar fluid clearance (AFC), which foster the development of pulmonary permeability edema and hamper gas exchange. Tumor Necrosis Factor (TNF) is an evolutionarily conserved pleiotropic cytokine, involved in host immune defense against pathogens and cancer. TNF exists in both membrane-bound and soluble form and its mainly -but not exclusively- pro-inflammatory and cytolytic actions are mediated by partially overlapping TNFR1 and TNFR2 binding sites situated at the interface between neighboring subunits in the homo-trimer. Whereas TNFR1 signaling can mediate hyper-inflammation and impaired barrier function and AFC in the lungs, ligand stimulation of TNFR2 can protect from ventilation-induced lung injury. Spatially distinct from the TNFR binding sites, TNF harbors within its structure a lectin-like domain that rather protects lung function in ARDS. The lectin-like domain of TNF -mimicked by the 17 residue TIP peptide- represents a physiological mediator of alveolar-capillary barrier protection. and increases AFC in both hydrostatic and permeability pulmonary edema animal models. The TIP peptide directly activates the epithelial sodium channel (ENaC) -a key mediator of fluid and blood pressure control- upon binding to its α subunit, which is also a part of the non-selective cation channel (NSC). Activity of the lectin-like domain of TNF is preserved in complexes between TNF and its soluble TNFRs and can be physiologically relevant in pneumonia. Antibody- and soluble TNFR-based therapeutic strategies show considerable success in diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease, but their chronic use can increase susceptibility to infection. Since the lectin-like domain of TNF does not interfere with TNF's anti-bacterial actions, while exerting protective actions in the alveolar-capillary compartments, it is currently evaluated in clinical trials in ARDS and COVID-19. A more comprehensive knowledge of the precise role of the TNFR binding sites versus the lectin-like domain of TNF in lung injury, tissue hypoxia, repair and remodeling may foster the development of novel therapeutics for ARDS.

State of the Art: The Immunomodulatory Role of MSCs for Osteoarthritis

Osteoarthritis (OA) has generally been introduced as a degenerative disease; however, it has recently been understood as a low-grade chronic inflammatory process that could promote symptoms and accelerate the progression of OA. Current treatment strategies, including corticosteroid injections, have no impact on the OA disease progression. Mesenchymal stem cells (MSCs) based therapy seem to be in the spotlight as a disease-modifying treatment because this strategy provides enlarged anti-inflammatory and chondroprotective effects. Currently, bone marrow, adipose derived, synovium-derived, and Wharton's jelly-derived MSCs are the most widely used types of MSCs in the cartilage engineering. MSCs exert immunomodulatory, immunosuppressive, antiapoptotic, and chondrogenic effects mainly by paracrine effect. Because MSCs disappear from the tissue quickly after administration, recently, MSCs-derived exosomes received the focus for the next-generation treatment strategy for OA. MSCs-derived exosomes contain a variety of miRNAs. Exosomal miRNAs have a critical role in cartilage regeneration by immunomodulatory function such as promoting chondrocyte proliferation, matrix secretion, and subsiding inflammation. In the future, a personalized exosome can be packaged with ideal miRNA and proteins for chondrogenesis by enriching techniques. In addition, the target specific exosomes could be a gamechanger for OA. However, we should consider the off-target side effects due to multiple gene targets of miRNA.

Potential Immune Indicators for Predicting the Prognosis of COVID-19 and Trauma: Similarities and Disparities

Although cellular and molecular mediators of the immune system have the potential to be prognostic indicators of disease outcomes, temporal interference between diseases might affect the immune mediators, and make them difficult to predict disease complications. Today one of the most important challenges is predicting the prognosis of COVID-19 in the context of other inflammatory diseases such as traumatic injuries. Many diseases with inflammatory properties are usually polyphasic and the kinetics of inflammatory mediators in various inflammatory diseases might be different. To find the most appropriate evaluation time of immune mediators to accurately predict COVID-19 prognosis in the trauma environment, researchers must investigate and compare cellular and molecular alterations based on their kinetics after the start of COVID-19 symptoms and traumatic injuries. The current review aimed to investigate the similarities and differences of common inflammatory mediators (C-reactive protein, procalcitonin, ferritin, and serum amyloid A), cytokine/chemokine levels (IFNs, IL-1, IL-6, TNF-α, IL-10, and IL-4), and immune cell subtypes (neutrophil, monocyte, Th1, Th2, Th17, Treg and CTL) based on the kinetics between patients with COVID-19 and trauma. The mediators may help us to accurately predict the severity of COVID-19 complications and follow up subsequent clinical interventions. These findings could potentially help in a better understanding of COVID-19 and trauma pathogenesis.

Influence of the inflammasome complex on psychiatric disorders: clinical and preclinical studies

INTRODUCTION

The innate immune complex, an inflammasome complex, has a role in the etiology of psychiatric disorders. Preclinical studies have demonstrated that the inflammasome activation leads to psychiatric disorders and clinical studies have proved that specific psychiatric illnesses are associated with aberrant levels of inflammatory cytokines and inflammasome. The inflammasome complex could be a major factor in the progression and pathology of psychiatric disorders.

AREA COVERED

We discuss the pathogenesis of psychiatric disorders with respect to the activation of the inflammasome complex. Inflammasome-associated inflammatory cytokines are observed in patients and animal models of psychiatric disorders. The article also reflects on inflammasome regulatory options for the prevention and treatment of psychiatric disorders. Relevant literature available on PubMed from 1992 to 2021 has been included in this review.

EXPERT OPINION

Modulating the inflammasome complex is a potential therapeutic strategy to treat symptom severity for patients with psychiatric disorders, particularly those with inflammasome-associated disorders. However, the nature of the psychiatric disorders should be considered when targeting inflammasome.

Inflammatory Molecules Released by Mechanically Injured Astrocytes Trigger Presynaptic Loss in Cortical Neuronal Networks

Deformation, compression, or stretching of brain tissues cause diffuse axonal injury (DAI) and induce structural and functional alterations of astrocytes, the most abundant cell type in the brain. To gain further insight into the role of mechanically activated astrocytes on neuronal networks, this study was designed to investigate whether cytokines released by mechanically activated astrocytes can affect the growth and synaptic connections of cortical neuronal networks. Astrocytes were cultivated on elastic membranes and subjected to repetitive mechanical insults, whereas well-defined protein micropatterns were used to form standardized neuronal networks. GFAP staining showed that astrocytes were mechanically activated after two cycles of stretch and mesoscale discovery assays indicated that injured astrocytes released four major cytokines. To understand the role of these cytokines, neuronal networks were cultured with the supernatant of healthy or mechanically activated astrocytes, and the individual contribution of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) was studied. We found that the supernatant of two-cycle stretched astrocytes decreased presynaptic terminals and indicated that TNF-α must be considered a key player of the synaptic loss. Furthermore, our results indicate that cytokines released by injured astrocytes significantly modulate the balance between TNFR1 and TNFR2 receptors by enhancing R2 receptors. We demonstrated that TNF-α is not involved in this process, suggesting a predominant role of other secreted cytokines. Together, these results contribute to a better understanding of the consequences of repetitive astrocyte deformations and highlight the role of inflammatory signaling pathways in synaptic plasticity and modulation of TNFR1 and TNFR2 receptors.

The ameliorative role of Physalis pubescens L. against neurological impairment associated with streptozotocin induced diabetes in rats

Neuropathy is considered a critical complication of diabetes mellitus (DM). Scientific studies are needed to relieve these painful complications. The current study aims to estimate the ameliorative role of Physalis juice (PJ) against neurological impairment in streptozotocin (STZ)-induced diabetic rats. Type 1 DM was induced after one week of injecting rats with 55 mg STZ/kg body weight. PJ-treated rats were orally administered 5 ml PJ/kg body weight per day for 28 days after induction of diabetes. A small piece of the cerebral cortex of rats was fixed and used for histopathological investigations. The remaining portion of the cerebral cortex was homogenized for biochemical and molecular analyses. As compared to the controls, STZ-injected rats showed significant elevations in the levels of blood glucose, tumor necrosis factor alfa, interleukin-1β, malondialdehyde, nitric oxide, and expression levels of caspase-3 and B-cell lymphoma-2 associated X-protein. Additionally, remarkable declines in the levels of brain-derived neurotrophic factor, monoamines, B-cell lymphoma-2, glutathione, as well as the activities and gene expression levels of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in STZ-treated rats were reported. Moreover, some histopathological alterations were observed in the brain cortex of the STZ-treated rats. On the other hand, the administration of PJ substantially reduced the blood glucose and alleviated the above-mentioned alterations in all the studied parameters of the cerebral cortex. In conclusion, an oral administration of 5 ml PJ/kg revealed a neuroprotective action against neurodegenerative diabetes-induced complications in rats, which might be due to the reported antioxidative and anti-inflammatory actions of PJ. Thus, further therapeutic studies are recommended to apply PJ in the treatment regimen of diabetes.

Profiling and Characterization of Localized Cytokine Response in Congenital Cleft Affected Lip Tissue

(1) Background: Despite cleft lips and palates belonging to the most common orofacial congenital anomalies, their morphopathogenesis is not yet fully understood. The study aimed to determine the distribution and relation of cytokines interferon-γ (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-2, IL-7, IL-12, and IL-13 in the cleft affected mucosa of the lip. (2) Materials and Methods: Twenty cleft lip (CL) mucosal samples and seven control tissues of oral cavity mucosa were included in the study. Specimen were obtained during reconstruction surgeries and processed by hematoxylin and eosin staining and immunohistochemistry for IFN-γ, TNF-α, IL-2, IL-7, IL-12, and IL-13. (3) Results: The distribution of cytokines was higher overall in the cleft affected epithelium compared to the connective tissue, with TNF-a, IL-2, and IL-12 displaying the highest number of immunopositive cells. With the exception of IL-2, CL specimen showed higher immunoreactivity. IFN-γ displayed only minor immunoreactivity, with no expression in the control epithelium. Correlation analysis was strongest between CL epithelial IL-13 and IFN-γ (z = 0.71, p < 0.0001). (4) Conclusions: The CLP affected epithelium displays high degrees of plasticity in expressing different cytokines, pointing towards the stimulation of a local adaptive immune response based on consistent inflammatory processes.

Formulated Chinese medicine Shaoyao Gancao Tang reduces NLRP1 and NLRP3 in Alzheimer's disease cell and mouse models for neuroprotection and cognitive improvement

Amyloid β (Aβ) plays a major role in the neurodegeneration of Alzheimer’s disease (AD). The accumulation of misfolded Aβ causes oxidative stress and inflammatory damage leading to apoptotic cell death. Traditional Chinese herbal medicine (CHM) has been widely used in treating neurodegenerative diseases by reducing oxidative stress and neuroinflammation. We examined the neuroprotective effect of formulated CHM Shaoyao Gancao Tang (SG-Tang, made of Paeonia lactiflora and Glycyrrhiza uralensis at 1:1 ratio) in AD cell and mouse models. In Aβ-GFP SH-SY5Y cells, SG-Tang reduced Aβ aggregation and reactive oxygen species (ROS) production, as well as improved neurite outgrowth. When the Aβ-GFP-expressing cells were stimulated with conditioned medium from interferon (IFN)-γ-activated HMC3 microglia, SG-Tang suppressed expressions of inducible nitric oxide synthase (iNOS), NLR family pyrin domain containing 1 (NLRP1) and 3 (NLRP3), tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, attenuated caspase-1 activity and ROS production, and promoted neurite outgrowth. In streptozocin-induced hyperglycemic APP/PS1/Tau triple transgenic (3×Tg-AD) mice, SG-Tang also reduced expressions of NLRP1, NLRP3, Aβ and Tau in hippocampus and cortex, as well as improved working and spatial memories in Y maze and Morris water maze. Collectively, our results demonstrate the potential of SG-Tang in treating AD by moderating neuroinflammation.

Targeted Inhibition of FTO Demethylase Protects Mice Against LPS-Induced Septic Shock by Suppressing NLRP3 Inflammasome

Sepsis refers to the systemic inflammatory response syndrome caused by infection. It is a major clinical problem and cause of death for patients in intensive care units worldwide. The Fat mass and obesity-related protein (FTO) is the primary N⁶-methyladenosine demethylase. However, the role of FTO in the pathogenesis of inflammatory diseases remains unclear. We herein show that nanoparticle-mediated Fto-siRNA delivery or FTO inhibitor entacapone administration dramatically inhibited macrophage activation, reduced the tissue damage and improved survival in a mouse model of LPS-induced endotoxic shock. Importantly, ablation of FTO could inhibit NLRP3 inflammasome through FoxO1/NF-κB signaling in macrophages. In conclusion, FTO is involved in inflammatory response of LPS-induced septic shock and inhibition of FTO is promising for the treatment of septic shock.

Vagus nerve stimulation enhances the cholinergic anti-inflammatory pathway to reduce lung injury in acute respiratory distress syndrome via STAT3

The cholinergic anti-inflammatory pathway (CAIP) is important for antagonizing inflammation and treating several diseases, including acute respiratory distress syndrome (ARDS), and is related to vagus nerve integrity. However, its underlying pathophysiological mechanism is still unclear. We hypothesized that CAIP regulates lung injury repair after ARDS through the STAT3 signaling pathway, which is an important downstream effector of α7nAchR. We enhanced CAIP activity by subjecting rats to vagus nerve stimulation (VNS), and administered the α-7 acetylcholine receptor (α7nAchR) agonist and antagonist to determine whether VNS can reduce lung injury by regulating the pulmonary inflammatory response through CAIP. After being subjected to VNS, the secretion of TNF-α and IL-1β was decreased, while the level of IL-10 was increased in the rat model of ARDS. Moreover, VNS treatment reduced lung mRNA levels of M1 macrophage markers, while increased those of M2 macrophage markers. The expression of Caspase-1 decreased, while that of STAT3 increased in lung tissue after VNS treatment. The aforementioned effects of VNS were reversed by cutting the cervical vagus efferent branch and blocking α7nAchR. These findings suggest that VNS inhibits the ARDS inflammatory response by promoting CAIP activity. Next, we used lentivirus knockdown of STAT3 expression to explore the mechanism of VNS through CAIP on lung inflammation in ARDS model rats. VNS activates α7nAchR, increases STAT3 expression, reduces Caspase-1 expression, suppresses inflammation by inhibiting inflammatory pyroptosis and M1 to M2 macrophage transformation, which may constitute the main mechanism of VNS action in ARDS.

Interleukin-1β, Oxidative Stress, and Abnormal Calcium Handling Mediate Diabetic Arrhythmic Risk

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Diabetes-induced arrhythmic risk involved activation of innate immunity, elevation of IL-1β, mitochondrial oxidative stress, SR calcium release channel oxidation, and QT prolongation.

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Diabetes-induced arrhythmic risk could be inhibited by IL-1β antagonism, mitoROS scavenging, and SR calcium release stabilization.

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The relationship of inflammation and arrhythmic risk may account for increased susceptibility of diabetic patients to the effects of COVID-19.

Diabetes mellitus (DM) is associated with increased arrhythmia. Type 2 DM (T2DM) mice showed prolonged QT interval and increased ventricular arrhythmic inducibility, accompanied by elevated cardiac interleukin (IL)-1β, increased mitochondrial reactive oxygen species (mitoROS), and oxidation of the sarcoplasmic reticulum (SR) Ca²⁺ release channel (ryanodine receptor 2 [RyR2]). Inhibiting IL-1β and mitoROS reduced RyR2 oxidation and the ventricular arrhythmia in DM. Inhibiting SR Ca2⁺ leak by stabilizing the oxidized RyR2 channel reversed the diabetic arrhythmic risk. In conclusion, cardiac IL-1β mediated the DM-associated arrhythmia through mitoROS generation that enhances SR Ca²⁺ leak. The mechanistic link between inflammation and arrhythmias provides new therapeutic options.

Co-administration of Luteolin mitigated toxicity in rats' lungs associated with doxorubicin treatment

Doxorubicin (DOX), is a drug against lung malignancies with undesirable side effect including oxidative, inflammatory and apoptotic effects. Luteolin (LUT), present in fruits and vegetables is pharmacologically active against oxido-inflammatory and apoptotic responses. The present study examined the effect of LUT on DOX-induced lungs and blood dysfunction in Wistars rat (sex: male; 10 weeks old, 160 ± 5 g). Randomly grouped (n = 10) rats were treated as follows: control, LUT alone (100 mg/kg; per os), DOX (2 mg/kg; i. p), and co-treated rats with LUT (50 or 100 mg/kg) and DOX for two consecutive weeks. DOX alone adversely altered the final body and relative organ weights, red and white blood cell and platelet counts. DOX significantly (p > 0.05) reduced lungs antioxidant capacity, and anti-inflammatory cytokines; increased biomarkers of oxidative stress, caspase-3 activity, and pro-inflammatory cytokine. Morphological damages accompanied these biochemical alterations in the lung of experimental rats. Co-treatment with LUT, dose-dependently reversed DOX-mediated changes in rats' survival, toxic responses, and diminished oxidative stress in rat's lungs. Furthermore, co-treatment with LUT resulted in the reduction of pro-inflammatory cytokines and apoptotic biomarkers, increased red and white blood cell, platelet counts and abated pathological injuries in rat lungs treated with DOX alone. In essence, our findings indicate that LUT dose-dependently mitigated DOX-induced toxicities in the lungs and haematopoietic systems. Supplementation of patients on DOX-chemotherapy with phytochemicals exhibiting antioxidant activities, specifically LUT, could circumvent the onset of unintended toxic responses in the lungs and haematopoietic system exposed to DOX.

Effect of 808-nm Laser Photobiomodulation Treatment in Blepharitis Rat Model

PURPOSE

Blepharitis, simply defined as eyelid inflammation, is one of the common ocular conditions associated with discomfort and irritation. Because blepharitis causes meibomian gland dysfunction and dry eye, this study aimed to confirm the effect of photobiomodulation (PBM) on blepharitis.

METHODS

A total of 20 rats were randomly assigned to 4 equal groups, including control, blepharitis, PBM, and eye drop. Blepharitis was induced in rats by injecting complete Freund's adjuvant in the eyelid margins. PBM intervention was given every 3 days after blepharitis induction. Clinical signs including tear volume, tear breakup time (TBUT), meibomian gland swelling, fluorescein, telangiectasia, and meibomian gland secretion scores were measured every week, and the rats were killed for histological analysis after 4 weeks. Immunohistochemistry was performed to compare the level of inflammatory cytokines, interleukin-1β and tumor necrosis factor-α, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining on retina was performed to observe any retinal damage.

RESULTS

Tear volume and TBUT increased with PBM intervention, and with improved eyelid swelling, corneal staining, telangiectasia, and meibomian gland secretion scores increased. Hematoxylin and eosin staining showed no structural abnormalities of meibomian gland caused by blepharitis induction. Immunohistochemistry revealed that the levels of inflammatory cytokines interleukin-1β and tumor necrosis factor-α were lowered with PBM treatment in both eyelid and conjunctiva. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining showed no retinal damage.

CONCLUSIONS

Laser PBM at 808 nm was effective in alleviating ocular signs and controlling inflammation in blepharitis rat model. The in vivo results suggest that PBM has the potential to be used in treating blepharitis patients.

Peptides from Extruded Lupin (Lupinus albus L.) Regulate Inflammatory Activity via the p38 MAPK Signal Transduction Pathway in RAW 264.7 Cells

In this study, protein was extracted from extruded lupin and submitted to gastroduodenal digests to obtain lupin peptides, which were characterized using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After this, IQDKEGIPPDQQR (IQD), the lupine peptide monomer characterized after UPLC-MS/MS, was screened out by macrophage inflammatory cytokine production assay. RNA-sequencing analysis was performed to explore the mechanisms underlying the anti-inflammatory activity associated with this peptide. The results indicated that lupin peptides effectively inhibited the lipopolysaccharide-induced overproduction of proinflammatory mediators. IQD inhibited the production of tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and monocyte chemoattractant protein-1 by 51.20, 38.52, 44.70, and 40.43%, respectively. RNA-sequencing results showed that IQD inhibited the inflammatory response by regulating the gene expression of the p38 mitogen-activated protein kinase pathway and inhibiting downstream inflammatory cytokines. These bioactive peptides may be used to develop new ingredients for anti-inflammatory nutritional supplements.

TNF-α inhibition decreases MMP-2 activity, reactive oxygen species formation and improves hypertensive vascular hypertrophy independent of its effects on blood pressure

Systemic arterial hypertension is a public health problem associated with an increased risk of cardiovascular disease. Matrix metalloproteinases (MMP) are endopeptidases that participate in hypertension-induced cardiovascular remodeling, which may be activated by oxidative stress. Angiotensin II (Ang II), a potent hypertrophic and vasoconstrictor peptide, increases oxidative stress, MMP-2 activity and tumor necrosis factor (TNF-α) expression. In vitro studies have shown that TNF-α is essential for Ang II-induced MMP-2 expression. Thus, this study evaluated whetherTNF-α inhibition decreases the development of hypertension-induced vascular remodeling via reduction of MMP-2 activity and reactive oxygen species (ROS) formation. Two distinct pharmacological approaches were used in the present study: Pentoxifylline (PTX), a non-selective inhibitor of phosphodiesterases that exerts anti- inflammatory effects via inhibition of TNF-α, and Etanercept (ETN), a selective TNF-α inhibitor. 2-kidney and 1-Clip (2K1C). 2-kidney and 1-Clip (2K1C) and Sham rats were treated with Vehicle, PTX (50 mg/Kg and 100 mg/kg daily) or ETN (0.3 mg/Kg and 1 mg/kg; three times per week). Systolic blood pressure (SBP) was measured weekly by tail cuff plethysmography. Plasma TNF-α and IL-1β levels were evaluated by enzyme-linked immunosorbent assay (ELISA) technique. The vascular hypertrophy was examined in the aorta sections stained with hematoxylin/eosin. ROS in aortas was evaluated by dihydroethidium and chemiluminescence lucigenin assay. Aortic MMP-2 levels and activity were evaluated by gel zymography and in situ zymography, respectively. The 2K1C animals showed a progressive increase in SBP levels and was accompanied by significant vascular hypertrophy (p < 0.05 vs Sham). Treatment with PTX at higher doses decreased SBP and vascular remodeling in 2K1C animals (p < 0.05 vs 2K1C vehicle). Although the highest dose of ETN treatment did not reduce blood pressure, the vascular hypertrophy was significantly attenuated in 2K1C animals treated with ETN1 (p < 0.05). The increased cytokine levels and ROS formation were reversed by the highest doses of both PTX and ETN. The increase in MMP-2 levels and activity in 2K1C animals were reduced by PTX100 and ETN1 treatments (p < 0.05 vs vehicle 2K1C). Lower doses of PTX and ETN did not affect any of the evaluated parameters in this study, except for a small reduction in TNF-α levels. The findings of the present study suggest that PTX and ETN treatment exerts immunomodulatory effects, blunted excessive ROS formation, and decreased renovascular hypertension-induced MMP-2 up-regulation, leading to improvement ofvascular remodeling typically found in 2K1C hypertension. Therefore, strategies using anti-hypertensive drugs in combination with TNF alpha inhibitors could be an attractive therapeutic approach to tackle hypertension and its associated vascular remodeling.

Multiple roles of caspase-8 in cell death, inflammation, and innate immunity

Caspase-8 is an apical caspase involved in the programmed form of cell death called apoptosis that is critically important for mammalian development and immunity. Apoptosis was historically described as immunologically silent in contrast to other types of programmed cell death such as necroptosis or pyroptosis. Recent reports suggest considerable crosstalk between these different forms of cell death. It is becoming increasingly clear that caspase-8 has many non-apoptotic roles, participating in multiple processes including regulation of necroptosis (mediated by receptor-interacting serine/threonine kinases, RIPK1-RIPK3), inflammatory cytokine expression, inflammasome activation, and cleavage of IL-1β and gasdermin D, and protection against shock and microbial infection. In this review, we discuss the involvement of caspase-8 in cell death and inflammation and highlight its role in innate immune responses and in the relationship between different forms of cell death. Caspase-8 is one of the central components in this type of crosstalk.

Beneficial Effects of Inflammatory Cytokine-Targeting Aptamers in an Animal Model of Chronic Prostatitis

Non-bacterial prostatitis is an inflammatory disease that is difficult to treat. Oligonucleotide aptamers are well known for their stability and flexibility in conjugating various inflammatory molecules. In this study, we investigated the effects of inflammatory cytokine-targeting aptamers (ICTA), putative neutralizers of TNF-alpha and IL-1 beta activation, on local carrageenan-induced prostate inflammation, allodynia, and hyperalgesia in rats. In vitro evaluation confirmed the binding capability of ICTA. Intraprostatic injection of carrageenan or control vehicle was performed in six-week-old rats, and ICTA (150 µg) or vehicle was administered in the prostate along with carrageenan injection. The von Frey filament test was performed to determine mechanical allodynia, and prostate inflammation was examined seven days after drug administration. Local carrageenan administration resulted in a reduction of the tactile threshold. The levels of mononuclear cell infiltration, pro-inflammatory cytokine interleukin-1 beta (b), caspase-1 (casp-1), and Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing proteins 1 and 3 (NALP1 and NALP3) in the prostate of rats were increased seven days after carrageenan injection. Treatment with ICTA significantly attenuated the carrageenan-induced hyperalgesia and reduced the elevated levels of proteins including TNF-a and IL-1b in the rats. Apoptosis markers, B-cell lymphoma 2-associated X protein (Bax) and caspase-3, were elevated in ICTA-treated Chronic pelvic pain syndrome (CPPS) rats. These results suggest that ICTA provides protection against local carrageenan-induced enhanced pain sensitivity, and that the neutralization of proinflammatory cytokines may result in inflammatory cell apoptosis.

Promoted Viability and Differentiated Phenotype of Cultured Chondrocytes With Low Level Laser Irradiation Potentiate Efficacious Cells for Therapeutics

Effective clinical treatments of cartilage lesions in affected joints require large numbers of viable chondrogenic cells generated through in vivo stimulation or ex vivo expansion of chondrocytes isolated from small biopsy specimens. Conventional passaging of chondrocytes in culture provides sufficient cells for treatments but these cells usually lose their differentiated phenotype. This leads to the formation of fibrocartilaginous tissue due to a malfunctioning repair process. Biostimulation of passaging chondrocytes with low level laser irradiation (LLLI) may theoretically produce more functional chondrocytes for cell-based repair of cartilage defects. Molecular and cellular analyses, cytochemistry, cell cultivation, and microscopy showed that LLLI treatments were found to (1) increase chondrocyte viability, (2) promote secretion of matrix proteins, (3) upregulate expression of chondrogenic genes, and (4) downregulate gene expression of cell destructive proteases and genes coding for mediators involved in the extrinsic apoptosis signaling pathway. Furthermore, LLLI attenuated induction of genes associated with cell death and matrix breakdown induced by IL-1β, some of which was seen at the protein level, with verification of effects on gene expression in the C28/I2 human chondrocyte line. LLLI treatments during culture generated larger numbers of viable chondrocytes compared to untreated cultures. Moreover, LLLI-treated chondrocytes in culture also rectified and simultaneously maintained their differentiated phenotype. Cultured chondrocytes treated with LLLI are a promising cell source for repairing cartilage lesions in vivo and restoration of articular function using tissue engineering strategies.

Development and application of an antibody that binds to interleukin-1β of various mammalian species for the treatment of inflammatory diseases

Inflammation is provoked by host immune reactions to pathogenic or tissue injury and is arbitrated by cytokines. Among the pro-inflammatory cytokines, the tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) are main mediators of inflammation. The production of these pro-inflammatory cytokines is mainly triggered in macrophages by harmful stimuli including microbial pathogens, irritants, and toxic cellular components, and plays key roles in the palpation of the inflammatory response. Among the therapeutic antibodies for the treatment of inflammation, those targeting TNF-α (including adalimumab and infliximab) are frequently used in clinical settings. Although IL-1β is a key cytokine for the onset of inflammatory diseases, such as inflammatory bowel disease (IBD) and type 2 diabetes (T2DM), few therapeutic antibodies exist for this cytokine, with the exception of canakinumab. Canakinumab binds to human IL-1β, but does not bind to murine IL-1β, which hampers its experimental use. Therefore, inflammation-therapeutic antibodies that bind to IL-1β of various mammals are needed. In this study, we report the development of an antibody that bound to IL-1β of various mammalian species and exhibited therapeutic effects in inflammatory diseases.

The Role of Inflammation in the Pathogenesis of Osteoarthritis

A joint is the point of connection between two bones in our body. Inflammation of the joint leads to several diseases, including osteoarthritis, which is the concern of this review. Osteoarthritis is a common chronic debilitating joint disease mainly affecting the elderly. Several studies showed that inflammation triggered by factors like biomechanical stress is involved in the development of osteoarthritis. This stimulates the release of early-stage inflammatory cytokines like interleukin-1 beta (IL-1β), which in turn induces the activation of signaling pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), and mitogen-activated protein kinase (MAPK). These events, in turn, generate more inflammatory molecules. Subsequently, collagenase like matrix metalloproteinases-13 (MMP-13) will degrade the extracellular matrix. As a result, anatomical and physiological functions of the joint are altered. This review is aimed at summarizing the previous studies highlighting the involvement of inflammation in the pathogenesis of osteoarthritis.

Regulation of Staphylococcus aureus-induced CXCR1 expression via inhibition of receptor mobilization and receptor shedding during dual receptor (TNFR1 and IL-1R) neutralization

Our earlier studies proposed a radically new idea suggesting interdependency between TNF-α/TNFR1 and IL-1β/IL-1R pathways in modulation of Staphylococcus aureus-induced CXCL8/CXCR1 axis. However, the effects of inhibition of cytokine receptor mobilization at intracellular level and surface TNFR1 and IL-1R shedding on S. aureus-induced CXCR1 expression have not been studied so far in peritoneal macrophages. This study aimed to investigate the role of inhibition of receptor mobilization from the intracellular pool (using brefeldin A) and surface receptor shedding (using TAPI-1) on CXCR1 expression during dual receptor (TNFR1 plus IL-1R) neutralization in peritoneal macrophages isolated from wild-type Swiss Albino mice. Release of superoxide anion, nitric oxide, and hydrogen peroxide was measured and cytokine production was done by ELISA. Expression of surface receptors (TNFR1, IL-1R, and CXCR1) and inflammatory mediators was studied by Western blot. It was observed that S. aureus-infected macrophages showed elevated ROS production, secretion of TNF-α, IL-1β, and CXCL8, along with increased expression of surface receptors (TNFR1, IL-1R, and CXCR1), and inflammatory markers (iNOS and COX-2) compared with control or treated groups (p < 0.05). However, prior treatment of macrophages with BFA or TAPI-1 in the presence of anti-TNFR1 antibody and IRAP during S. aureus infection showed significant reduction of all these parameters (p < 0.05). We can conclude that targeting of TNFR1 and IL-1R (with major focus on surface expression study) either through blockage of intracellular receptor trafficking pathway or via surface receptor shedding diminishes TNFR1/IL-1R interaction and consequently downregulates CXCR1 expression along with inflammatory signalling pathways during bacterial infections.

Airway exposure to Staphylococcal enterotoxin type B (SEB) enhances the number and activity of bone marrow neutrophils via the release of multiple cytokines

BACKGROUND

The lung infections by Staphylococcus aureus are strongly associated with its ability to produce enterotoxins. However, little is known about the mechanisms underlying trafficking of bone marrow (BM) neutrophils during airway inflammation induced by Staphylococcal enterotoxin B (SEB). We therefore aimed to investigate the effects of mouse airways SEB exposure on BM neutrophil counts and its adhesive properties as well as on the release of cytokines/chemokines that orchestrate BM neutrophils trafficking to lung tissue.

METHODS

Male BALB/c mice were intranasally exposed to SEB (1 µg), and at 4, 16 and 24 h thereafter, BM, circulating blood, bronchoalveolar lavage (BAL) fluid and lung tissue were collected. BM neutrophils adhesion, MAC-1 and LFA1-α expressions (by flow cytometry) as well as measurement of cytokine and/or chemokines levels were assayed after SEB-airway exposure.

RESULTS

Prior exposure to SEB promoted a marked influx of neutrophils to BAL and lung tissue, which was accompanied by increased counts of BM immature neutrophils and blood neutrophilia. BM neutrophil expressions of LFA1-α and MAC-1 were unchanged by SEB exposure whereas a significant enhancement of adhesion properties to VCAM-1 was observed. The early phase of airway SEB exposure was accompanied by high levels of GM-CSF, G-CSF, IFN-γ, TNF-α and KC/CXCL1, while the latter phase by the equilibrated actions of SDF1-α and MIP-2.

CONCLUSION

Mouse airways exposure to SEB induces BM cytokines/chemokines release and their integrated actions enhance the adhesion of BM neutrophils leading to acute lung injury.

Lipopolysaccharide induces neuroglia activation and NF-κB activation in cerebral cortex of adult mice

Lipopolysaccharide (LPS) acts as an endotoxin, releases inflammatory cytokines, and promotes an inflammatory response in various tissues. This study investigated whether LPS modulates neuroglia activation and nuclear factor kappa B (NF-κB)-mediated inflammatory factors in the cerebral cortex. Adult male mice were divided into control animals and LPS-treated animals. The mice received LPS (250 μg/kg) or vehicle via an intraperitoneal injection for 5 days. We confirmed a reduction of body weight in LPS-treated animals and observed severe histopathological changes in the cerebral cortex. Moreover, we elucidated increases of reactive oxygen species and oxidative stress levels in LPS-treated animals. LPS administration led to increases of ionized calcium-binding adaptor molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP) expression. Iba-1 and GFAP are well accepted as markers of activated microglia and astrocytes, respectively. Moreover, LPS exposure induced increases of NF-κB and pro-inflammatory factors, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Increases of these inflammatory mediators by LPS exposure indicate that LPS leads to inflammatory responses and tissue damage. These results demonstrated that LPS activates neuroglial cells and increases NF-κB-mediated inflammatory factors in the cerebral cortex. Thus, these findings suggest that LPS induces neurotoxicity by increasing oxidative stress and activating neuroglia and inflammatory factors in the cerebral cortex.

The RNA-binding protein Mex-3B plays critical roles in the development of steroid-resistant neutrophilic airway inflammation

While most asthma can be treated with steroids, about 10%, called severe asthma, is refractory to steroids. It has recently been shown that in a subgroup of severe asthma cases, neutrophils that infiltrate into the airways play an important role in inflammation. However, the mechanisms underlying this increased neutrophil infiltration are not well understood. Here, using a mouse model of steroid-resistant neutrophilic inflammation, we show that mice deficient for the RNA-binding protein Mex-3B have significantly less neutrophil infiltration in the airways than wild-type mice. We further demonstrate that Mex-3B post-transcriptionally upregulates CXCL2, a chemokine that induces neutrophil chemotaxis and migration. Moreover, we show that treatment with either anti-CXCL2 antibody or anti-Mex-3B antisense oligonucleotide suppresses neutrophilic allergic airway inflammation. These results suggest that Mex-3B-mediated induction of CXCL2 is crucial for steroid-resistant neutrophilic allergic airway inflammation. Our findings suggest new strategies for therapeutic intervention in steroid-resistant severe asthma.

Alpha7 nicotinic acetylcholine receptors in lung inflammation and carcinogenesis: Friends or foes?

The lung tissue expresses the cholinergic system including nicotinic acetylcholine receptors (nAChRs) which included in many physiologic and pathologic processes. Mounting evidence revealed that these receptors have important roles in lung carcinogenesis via modulating either stimulatory or inhibitory signaling pathways. Among different members of nicotinic receptors family, alpha7-subtype of nAChR (α7nAChR) is a critical mediator involved in both inflammatory responses and cancers. Several studies have shown that this receptor is the most powerful regulator of responses that stimulate lung cancer processes such as proliferation, angiogenesis, metastasis, and inhibition of apoptosis. Moreover, aside from its roles in the regulation of cancer pathways, there is growing evidence indicating that α7nAChR has profound impacts on lung inflammation through the cholinergic anti-inflammatory pathway. Regarding such diverse effects as well as the critical roles of nicotine as an activator of α7nAChR on lung cancer pathogenesis, its modulation has emerged as a promising target for drug developments. In this review, we aim to highlight the detrimental as well as the possible beneficial influences of α7nAChR downstream signaling cascades in the control of lung inflammation and cancer-associated properties. Consequently, by considering the significant global burden of lung cancer, delineating the complex influences of α7 receptors would be of great interest in designing novel anticancer and anti-inflammatory strategies for the patients suffering from lung cancer.

Pathological mechanisms and therapeutic outlooks for arthrofibrosis

Arthrofibrosis is a fibrotic joint disorder that begins with an inflammatory reaction to insults such as injury, surgery and infection. Excessive extracellular matrix and adhesions contract pouches, bursae and tendons, cause pain and prevent a normal range of joint motion, with devastating consequences for patient quality of life. Arthrofibrosis affects people of all ages, with published rates varying. The risk factors and best management strategies are largely unknown due to a poor understanding of the pathology and lack of diagnostic biomarkers. However, current research into the pathogenesis of fibrosis in organs now informs the understanding of arthrofibrosis. The process begins when stress signals stimulate immune cells. The resulting cascade of cytokines and mediators drives fibroblasts to differentiate into myofibroblasts, which secrete fibrillar collagens and transforming growth factor-β (TGF-β). Positive feedback networks then dysregulate processes that normally terminate healing processes. We propose two subtypes of arthrofibrosis occur: active arthrofibrosis and residual arthrofibrosis. In the latter the fibrogenic processes have resolved but the joint remains stiff. The best therapeutic approach for each subtype may differ significantly. Treatment typically involves surgery, however, a pharmacological approach to correct dysregulated cell signalling could be more effective. Recent research shows that myofibroblasts are capable of reversing differentiation, and understanding the mechanisms of pathogenesis and resolution will be essential for the development of cell-based treatments. Therapies with significant promise are currently available, with more in development, including those that inhibit TGF-β signalling and epigenetic modifications. This review focuses on pathogenesis of sterile arthrofibrosis and therapeutic treatments.

Elevated pre-activation basal level of nuclear NF-κB in native macrophages accelerates LPS-induced translocation of cytosolic NF-κB into the cell nucleus

Signaling via Toll-like receptor 4 (TLR4) in macrophages constitutes an essential part of the innate immune response to bacterial infections. Detailed and quantified descriptions of TLR4 signal transduction would help to understand and exploit the first-line response of innate immune defense. To date, most mathematical modelling studies were performed on transformed cell lines. However, properties of primary macrophages differ significantly. We therefore studied TLR4-dependent activation of NF-κB transcription factor in bone marrow-derived and peritoneal primary macrophages. We demonstrate that the kinetics of NF-κB phosphorylation and nuclear translocation induced by a wide range of bacterial lipopolysaccharide (LPS) concentrations in primary macrophages is much faster than previously reported for macrophage cell lines. We used a comprehensive combination of experiments and mathematical modeling to understand the mechanisms of this rapid response. We found that elevated basal NF-κB in the nuclei of primary macrophages is a mechanism increasing native macrophage sensitivity and response speed to the infection. Such pre-activated state of macrophages accelerates the NF-κB translocation kinetics in response to low agonist concentrations. These findings enabled us to refine and construct a new model combining both NF-κB phosphorylation and translocation processes and predict the existence of a negative feedback loop inactivating phosphorylated NF-κB.

Hepatoprotective Potential of Sargassum muticum against STZ-Induced Diabetic Liver Damage in Wistar Rats by Inhibiting Cytokines and the Apoptosis Pathway

Liver inflammation and necrosis are the foremost problems interlinked with diabetes mellitus (DM). The methanolic extract of Sargassum muticum (MESM) plays a hepatoprotective role in streptozotocin- (STZ-) induced hepatic injury. In this study, STZ exposure induced diabetes that augmented hepatic damage, which was reflected in serum enzyme markers, the cytokine network, and caspase-3 and caspase-9 levels in Group 2. Exposure to the MESM tremendously modulated the levels of hepatic enzyme markers ALP, ACP, ALT, and AST in Groups 3 and 4. The cytokine network was well regulated by suppressing the release of cytokines, and the levels of caspase-3 and caspase-9 were also reduced in Groups 3 and 4. The present study suggests that MESM treatment at 200 and 500 mg protected the liver and also minimizes the glucose level. Thus, the MESM plays a key role in rejuvenating the liver and can modulate diabetes's pathogenic effect by reducing the glucose level.

Differential gene expression to an LPS challenge in relation to exogenous corticosterone in the invasive cane toad (Rhinella marina)

The cane toad (Rhinella marina) is an invasive amphibian in several parts of the world. Much of the research performed on assessing the dispersal potential of invasive species has focused immunity. Invaders are predicted to rely less on pro-inflammatory immunity, allowing them to allocate energy to dispersal. Elevated stress may play a role in regulation of immune responses used by invasive species. RNA sequencing of spleen tissue from cane toads subjected to an acute LPS challenge revealed genes coding for cytokines involved in typical innate responses such as phagocytic cell recruitment, extravasation, inflammation, and lymphocyte differentiation were significantly upregulated, while toads receiving transdermal application of corticosterone in addition to an LPS injection showed downregulation of genes involved with cell mediated immunity. These results indicate hormonal changes associated with acute stress may alter investment into mounting cell-mediated or humoral responses while allowing for prolonged phagocytic innate responses in this invasive species.

Oral infection of mice with Fusobacterium nucleatum results in macrophage recruitment to the dental pulp and bone resorption

BACKGROUND

Fusobacterium nucleatum is a Gram-negative anaerobic bacterium associated with periodontal disease. Some oral bacteria, like Porphyromonas gingivalis, evade the host immune response by inhibiting inflammation. On the other hand, F. nucleatum triggers inflammasome activation and release of danger-associated molecular patterns (DAMPs) in infected gingival epithelial cells.

METHODS

In this study, we characterized the pro-inflammatory response to F. nucleatum oral infection in BALB/c mice. Western blots and ELISA were used to measure cytokine and DAMP (HMGB1) levels in the oral cavity after infection. Histology and flow cytometry were used to observe recruitment of immune cells to infected tissue and pathology.

RESULTS

Our results show increased expression and production of pro-inflammatory cytokines during infection. Furthermore, we observe that F. nucleatum infection leads to recruitment of macrophages in different tissues of the oral cavity. Infection also contributes to osteoclast recruitment, which could be involved in the observed bone resorption.

CONCLUSIONS

Overall, our findings suggest that F. nucleatum infection rapidly induces inflammation, release of DAMPs, and macrophage infiltration in gingival tissues and suggest that osteoclasts may drive bone resorption at early stages of the inflammatory process.

A Synbiotic with Tumor Necrosis Factor-α Inhibitory Activity Ameliorates Experimental Jejunoileal Mucosal Injury

Despite the recent development of biological modifiers for inflammatory bowel diseases (IBD), there continues to be considerable interest in fermented medicines because of its negligible adverse effects. We previously showed that the synbiotic Gut Working Tablet (GWT) alleviates experimental colitis. Here we show that GWT is capable of ameliorating jejunoileal mucosal injury, which is frequently seen with IBD. We created experimental jejunoileal mucositis in rats by injection of methotrexate (MTX) which increases intestinal permeability, a hallmark finding of IBD. Administering GWT to MTX-injected rats restored intestinal integrity by reversing villi shortening, crypt loss, and goblet cell depletion in the mucosa. Also GWT reduced activities of myeloperoxidase and lipid peroxidase and increased superoxide dismutase activity, which is critical for maintaining intestinal function. We further found that GWT suppressed mRNA expression of tumor necrosis factor-α (TNF-α) and interleukin-12 (IL-12) in macrophage and reduced TNF-α mRNA expression in specimens with experimental colitis, which is in contrast to VSL#3 that enhanced TNF-α production. Together, the current and previous animal studies clearly demonstrate the protective role of GWT in chemically induced enterocolitis. Crohn's disease, a well-known IBD, can affect any portion of the intestine, and these results suggest that GWT may be useful as a novel therapeutic or maintenance therapy for IBD.

Aortic dysfunction in metabolic syndrome mediated by perivascular adipose tissue TNFα- and NOX2-dependent pathway

NEW FINDINGS

What is the central question of this study? Tumour necrosis factor-α (TNFα) has been shown to impair vascular function, but the impact of thoracic aorta perivascular adipose tissue (tPVAT)-derived TNFα on tPVAT and aortic function in metabolic syndrome is unknown. What is the main finding and its importance? Release of TNFα by tPVAT causes production of reactive oxygen species in tPVAT through activation of an NADPH-oxidase 2 (NOX2)-dependent pathway, activates production of aortic reactive oxygen species and mediates aortic stiffness, potentially through matrix metalloproteinase 9 activity. Neutralization of TNFα and/or inhibition of NOX2 blocks the tPVAT-induced impairment of aortic function. These data partly implicate tPVAT NOX2 and TNFα in mediating the vascular pathology of metabolic syndrome.

ABSTRACT

Perivascular adipose tissue (PVAT) is recognized for its vasoactive effects, but it is unclear how metabolic syndrome impacts thoracic aorta (t)PVAT and the subsequent effect on functional and structural aortic stiffness. Thoracic aorta and tPVAT were removed from 16- to 17-week-old lean (LZR, n = 16) and obese Zucker rats (OZR, n = 16). The OZR presented with aortic endothelial dysfunction, assessed by wire myography, and increased aortic stiffness, assessed by elastic modulus. The OZR tPVAT exudate further exacerbated the endothelial dysfunction, reducing nitric oxide and endothelium-dependent relaxation (P < 0.05). Additionally, OZR tPVAT exudate had increased MMP9 activity (P < 0.05) and further increased the elastic modulus of the aorta after 72 h of co-culture (P < 0.05). We found that the observed aortic dysfunction caused by OZR tPVAT was mediated through increased production and release of tumour necrosis factor-α (TNFα; P < 0.01), which was dependent on tPVAT NADPH-oxidase 2 (NOX2) activity. The OZR tPVAT release of reactive oxygen species and subsequent aortic dysfunction were inhibited by TNFα neutralization and/or inhibition of NOX2. Additionally, we found that OZR tPVAT had reduced activity of the active sites of the 20S proteasome (P < 0.05) and reduced superoxide dismutase activity (P < 0.01). In conclusion, metabolic syndrome causes tPVAT dysfunction through an interplay between TNFα and NOX2 that leads to tPVAT-mediated aortic stiffness by activation of aortic reactive oxygen species and increased MMP9 activity.

Chenodeoxycholic acid activates NLRP3 inflammasome and contributes to cholestatic liver fibrosis

Accumulation of hydrophobic bile acids in the liver contributes to cholestatic liver injury. Inflammation induced by excessive bile acids is believed to play a crucial role, however, the mechanisms of bile acids triggered inflammatory response remain unclear. Recent studies have highlighted the effect of NLRP3 inflammasome in mediating liver inflammation and fibrosis. In this study, we for the first time showed that chenodeoxycholic acid (CDCA), the major hydrophobic primary bile acid involved in cholestatic liver injury, could dose-dependently induce NLRP3 inflammasome activation and secretion of pro-inflammatory cytokine-IL-1β in macrophages by promoting ROS production and K⁺ efflux. Mechanistically, CDCA triggered ROS formation in part through TGR5/EGFR downstream signaling, including protein kinase B, extracellular regulated protein kinases and c-Jun N-terminal kinase pathways. Meanwhile, CDCA also induced ATP release from macrophages which subsequently causes K⁺ efflux via P2X7 receptor. Furthermore, in vivo inhibition of NLRP3 inflammasome with caspase-1 inhibitor dramatically decreased mature IL-1β level of liver tissue and ameliorated liver fibrosis in bile duct ligation (BDL) mouse model. In conclusion, excessive CDCA may represent an endogenous danger signal to activate NLRP3 inflammasome and initiate liver inflammation during cholestasis. Our finding offers a mechanistic basis to ameliorate cholestatic liver fibrosis by targeting inflammasome activation.

Contribution of IL-1RI Signaling to Protection against Cryptococcus neoformans 52D in a Mouse Model of Infection

Interleukin-1 alpha (IL-1α) and interleukin-1 beta (IL-1β) are pro-inflammatory cytokines that are induced after Cryptococcus neoformans infection and activate the interleukin-1 receptor type I (IL-1RI). To establish the role of IL-1RI signaling in protection against cryptococcal infection, we analyzed wild-type (WT) and IL-1RI-deficient (IL-1RI^−/−) mice on the BALB/c background. IL-1RI^−/− mice had significantly reduced survival compared to WT mice after intratracheal challenge with C. neoformans 52D. Microbiological analysis showed a significant increase in the lung and brain fungal burden of IL-1RI^−/− compared to WT mice beginning at weeks 1 and 4 postinfection, respectively. Histopathology showed that IL-1RI^−/− mice exhibit greater airway epithelial mucus secretion and prominent eosinophilic crystals that were absent in WT mice. Susceptibility of IL-1RI^−/− mice was associated with significant induction of a Th2-biased immune response characterized by pulmonary eosinophilia, M2 macrophage polarization, and recruitment of CD4⁺ IL-13⁺ T cells. Expression of pro-inflammatory [IL-1α, IL-1β, TNFα, and monocyte chemoattractant protein 1 (MCP-1)], Th1-associated (IFNγ), and Th17-associated (IL-17A) cytokines was significantly reduced in IL-1RI^−/− lungs compared to WT. WT mice also had higher expression of KC/CXCL1 and sustained neutrophil recruitment to the lung; however, antibody-mediated depletion of these cells showed that they were dispensable for lung fungal clearance. In conclusion, our data indicate that IL-1RI signaling is required to activate a complex series of innate and adaptive immune responses that collectively enhance host defense and survival after C. neoformans 52D infection in BALB/c mice.

The cholinergic anti-inflammatory pathway: an innovative treatment strategy for respiratory diseases and their comorbidities

Over the past few decades, it has been clarified that the nervous system and immune system have overlapping distributions and their interactions are critical in the regulation of immunological and inflammatory responses. The cholinergic anti-inflammatory pathway, including the parasympathetic nerve systems and humoral factors orchestrate the immune responses to protect the body during infection and tissue injury. Recent investigations have attempted to clarify how the parasympathetic nerve systems attenuate the systemic inflammatory responses and identified the α7 nicotinic acetylcholine receptor (α7nAChR) as a crucial target for attenuating the release of inflammatory cytokines from inflammatory cells including macrophages and dendritic cells. This modulatory circuit pathway possibly exists in the lungs and might be involved in regulating inflammation and immunity during infection and other inflammatory lung diseases including asthma and COPD, which means that modulation of the cholinergic anti-inflammatory pathway is a possible therapeutic target for lung diseases.

Human Lymph Node-Derived Fibroblastic and Double-Negative Reticular Cells Alter Their Chemokines and Cytokines Expression Profile Following Inflammatory Stimuli

Lymph node (LN) is a secondary lymphoid organ with highly organized and compartmentalized structure. LNs harbor B, T, and other cells among fibroblastic reticular cells (FRCs). FRCs are characterized by both podoplanin (PDPN/gp38) expression and by the lack of CD31 expression. FRCs are involved in several immune response processes but mechanisms underlying their function are still under investigation. Double-negative cells (DNCs), another cell population within LNs, are even less understood. They do not express PDPN or CD31, their localization within the LN is unknown, and their phenotype and function remain to be elucidated. This study evaluates the gene expression and cytokines and chemokines profile of human LN-derived FRCs and DNCs during homeostasis and following inflammatory stimuli. Cytokines and chemokines secreted by human FRCs and DNCs partially diverged from those identified in murine models that used similar stimulation. Cytokine and chemokine secretion and their receptors expression levels differed between stimulated DNCs and FRCs, with FRCs expressing a broader range of chemokines. Additionally, dendritic cells demonstrated increased migration toward FRCs, possibly due to chemokine-induced chemotaxis since migration was significantly decreased upon neutralization of secreted CCL2 and CCL20. Our study contributes to the understanding of the biology and functions of FRCs and DNCs and, accordingly, of the mechanisms involving them in immune cells activation and migration.

IL-1β is a key cytokine that induces trypsin upregulation in the influenza virus-cytokine-trypsin cycle

Severe influenza is characterized by a cytokine storm, and the influenza virus-cytokine-trypsin cycle is one of the important mechanisms of viral multiplication and multiple organ failure. The aim of this study was to define the key cytokine(s) responsible for trypsin upregulation. Mice were infected with influenza virus strain A/Puerto Rico/8/34 (H1N1) or treated individually or with a combination of interleukin-1β, interleukin-6, and tumor necrosis factor α. The levels of these cytokines and trypsin in the lungs were monitored. The neutralizing effects of anti-IL-1β antibodies on cytokine and trypsin expression in human A549 cells and lung inflammation in the infected mice were examined. Infection induced interleukin-1β, interleukin-6, tumor necrosis factor α, and ectopic trypsin in mouse lungs in a dose- and time-dependent manner. Intraperitoneal administration of interleukin-1β combined with other cytokines tended to upregulate trypsin and cytokine expression in the lungs, but the combination without interleukin-1β did not induce trypsin. In contrast, incubation of A549 cells with interleukin-1β alone induced both cytokines and trypsin, and anti-interleukin-1β antibody treatment abrogated these effects. Administration of the antibody in the infected mice reduced lung inflammation area. These findings suggest that IL-1β plays a key role in trypsin upregulation and has a pathological role in multiple organ failure.