The interleukin (IL)-1 cytokine family--Balance between agonists and antagonists in inflammatory diseases

Hepatitis B Virus Reactivation Potentiated by Biologics

Hepatitis B virus (HBV) reactivation can be a serious complication for patients with chronic or resolved HBV infection when treated with biologics. For HBsAg-positive patients receiving biologics, the risk of HBV reactivation is moderate to high. HBsAg-negative/anti-HBc positive patients are at lower risk of HBV reactivation than HBsAg-positive patients. However, patients taking anti-CD20 agents, such as rituximab, have high risk of HBV reactivation (>10%), so antiviral prophylactic therapies are required. This review provides the different classes of biologics associated with HBV reactivation, stratifies the various reactivation risk levels by HBV status and biologic agent, and discusses management strategies.

The Peripheral Immune System and Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease that is defined by loss of upper and lower motor neurons, associated with accumulation of protein aggregates in cells. There is also pathology in extra-motor areas of the brain, Possible causes of cell death include failure to deal with the aggregated proteins, glutamate toxicity and mitochondrial failure. ALS also involves abnormalities of metabolism and the immune system, including neuroinflammation in the brain and spinal cord. Strikingly, there are also abnormalities of the peripheral immune system, with alterations of T lymphocytes, monocytes, complement and cytokines in the peripheral blood of patients with ALS. The precise contribution of the peripheral immune system in ALS pathogenesis is an active area of research. Although some trials of immunomodulatory agents have been negative, there is strong preclinical evidence of benefit from immune modulation and further trials are currently underway. Here, we review the emerging evidence implicating peripheral immune alterations contributing to ALS, and their potential as future therapeutic targets for clinical intervention.

Interleukin-1 Ligands and Receptors in Lumpfish (Cyclopterus lumpus L.): Molecular Characterization, Phylogeny, Gene Expression, and Transcriptome Analyses

The interleukin (IL)-1 family play a fundamental role as immune system modulators. Our previous transcriptome-analyses of leukocytes from lumpfish (Cyclopterus lumpus L.) showed that IL-1β was among the most highly upregulated genes following bacterial exposure. In the present study, we characterized IL-1 signaling pathways, identified and characterized four ligands of the IL-1 family in lumpfish; IL-1β type I and type II, IL-18, and the novel IL-1 family members (nIL-1F), both at mRNA and gene levels. The two IL-1β in lumpfish is termed IL-1β1 (type II) and IL-1β2 (type I). Furthermore, a comprehensive phylogenetic analysis of 277 IL-1 ligands showed that nIL-1F, in common with IL-1β, likely represents an ancestral gene, as representatives for nIL-1F were found in cartilaginous and lobe-finned fish, in addition to teleosts. This shows that nIL-1F is not exclusively present in teleosts as previously suggested. Our analyses of exon-intron structures, intron phases, phylogeny and synteny clearly show the separation of IL-1β into groups; type I and type II, which likely is a result of the third whole genome duplication (3R WGD). The phylogenetic analysis shows that most teleosts have both type I and type II. Furthermore, we have determined transcription levels of the IL-1 ligands in leukocytes and 16 different tissues, and their responses upon in vitro stimulation with seven different ligands. In addition, we have identified the IL-1 receptors IL-1R1, IL-1R2, IL-1R4 (ST2/IL-33 receptor/IL-1RL), IL-1R5 (IL-18R1), and partial sequences of DIGIRR and IL-1R3 (IL-RAcP). Identification of immune molecules and description of innate responses in lumpfish is interesting for comparative and evolutionary studies and our study constitutes a solid basis for further functional analyses of IL-1 ligands and receptors in lumpfish. Furthermore, since lumpfish are now farmed in large numbers to be used as cleaner fish for removal of sea lice on farmed salmon, in-depth knowledge of key immune molecules, signaling pathways and innate immune responses is needed, as the basis for design of efficient immune prophylactic measures such as vaccination.

Characterization of a Novel Interleukin-1 Receptor Antagonist from Sheep (Ovis aries)

Interleukin-1 receptor antagonist (IL-1Ra) is an antagonist of IL-1β binding IL-1β receptors but does not induce intracellular responses or signal transduction. In this study, the full-length complementary DNA (cDNA) of the IL-1Ra gene (OaIL-1Ra) was identified from sheep (Ovis aries) using rapid amplification of cDNA ends PCR and submitted to GenBank with the accession number KC425613. The OaIL-1Ra cDNA comprised an open reading frame of 525 bp encoding a protein of 19765.8 Da, a 5'-untranslated region (UTR) of 27 bp, and a 3'-UTR of 676 bp with a poly(A) tail. Recombinant OaIL-1Ra with bioactivity was expressed in a prokaryotic expression system, and a monoclonal antibody against native OaIL-1Ra was prepared. Through Western blot analyses, the OaIL-1Ra protein was widely expressed in lung, heart, spleen, liver, kidney, muscle, intestine, lymphonodi, rumen, and white blood cells, with the highest levels in liver and spleen. The expression of OaIL-1Ra in primary cultured white blood cells of sheep were highly induced in a time-dependent manner when challenged with different bacteria. These results implied that OaIL-1Ra is associated with immune responses during bacterial infections.

Association of Interleukin-1 and Inteleukin-1 Receptor Antagonist Gene Polymorphisms with Multiple Sclerosis in Azeri Population of Iran

BACKGROUND

Cytokines as important mediators have a critical role in appropriate immune responses, the irregular production of which can lead to Multiple Sclerosis (MS). Proinflammatory cytokine interleukin-1 (IL-1) triggers inflammatory responses. Function and production of the cytokine are influenced by IL-1 coding gene polymorphism and those antagonists gene polymorphism.

OBJECTIVE

The aim of the present study was to evaluate the possible correlation between MS and IL-1 related alleles in Azeri population of Iran.

METHODS

Variable number tandem repeats (VNTR) genotypes of 150 MS patients and 220 healthy non-relative controls were determined.

RESULTS

In the healthy controls, genotype TT at IL-1A (-889) location was significantly higher than the MS patients (p=0.0001). However, a significant difference was not found between the two groups in genotypic/allelic frequency at IL- 1B+ 3953 location. Evaluation of the IL-1RA gene revealed that genotype 1/2, and genotype 1/3 were significantly higher in the healthy controls and MS patients, respectively. Our findings indicated that the consumption of fast-food in MS patients was significantly higher than controls (p= <0.05). Also, a considerable number of MS patients had inappropriate dieting behaviors such as not eating breakfast (p= 0.0001), and irregular eating habits (p= 0.0001).

CONCLUSION

Polymorphisms of the IL-1B genes and common alleles of IL-1RA were not considered as risk factors for MS disease. However, genotype TT at IL-1A (-889) location and the rare allele of IL-1RA3 can be a potential risk factor for the disease. Furthermore, inappropriate dieting behaviors and consumption of fast-food can increase the risk of MS.

Prenatal two-hit stress affects maternal and offspring pregnancy outcomes and uterine gene expression in rats: match or mismatch?

Maternal stress and inflammation excesses can lead to adverse pregnancy outcomes and offspring development. We evaluated whether distinct prenatal stressors affect pregnancy, maternal and offspring outcomes, and uterine gene expression differently when combined than either alone. Long-Evans dams were exposed to psychological or/and (two-hit) immune stress (interleukin-1 beta [IL-1β]), on gestational days 12-18 and 17-delivery, respectively. Gestational length, maternal weight gain, glycaemia and corticosterone levels, offspring weight, and gender effects were recorded. Maternal and offspring uteri were collected at weaning and on postnatal day 160 correspondingly. Uterine expression of genes involved in local progesterone metabolism, neuroendocrine and immune systems were analyzed using quantitative real-time polymerase chain reaction. Maternal two-hit stress increased gestational length variation and the occurrence of adverse pregnancy outcomes while reducing gestational weight gain. Pup weight was negatively affected by prenatal stressors in a gender-specific way. In dams, IL-1β upregulated gene expression of neuroendocrine (Crh, Crhr1) and cytokine genes (Il1b, Il1rn, Il6, and Il10). Conversely, transcriptional patterns in offspring uteri were more variable with gene-specific up- or downregulation by each stressor separately, while exposure to both extensively reduced the expression of neuroendocrine (Hsd11b1), cytokine (Il1a, Il1rn, Il6), and IL-1 receptor genes. In conclusion, maternal stress affects physiological and molecular processes in dams and their offspring; two hits have different effects than single stressors. Outcomes appear generation-, gender-, and stressor-specific. Dampening of offspring uterine gene expression after exposure to multiple stressors could fit within the match/mismatch hypothesis of perinatal programming, with offspring preparing for a stressful life.

NLRP3 inflammasome inhibition attenuates subacute neurotoxicity induced by acrylamide in vitro and in vivo

Acrylamide (AA) constitutes an important industrial chemical agent and well-known neurotoxin. However, the mechanism underlying AA-mediated neurotoxicity is extremely complicated and controversial. In this study, we found that activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome and its subsequent downstream inflammatory responses plays an important role in AA-induced neurotoxicity mechanisms. In vitro experiments revealed that AA (2.5 mM) induced BV2 microglial cytotoxicity and triggered NLRP3 inflammasome activation along with downstream proinflammatory cytokine interleukin-1β and interleukin-18 expression. Treatment with inhibitor or NLRP3 siRNA efficiently protected BV2 microglial cells against AA-induced cytotoxicity and reversed NLRP3 inflammasome activation and its mediated inflammatory reaction. Similarly, AA exposure (50 mg/kg) for 10 consecutive days caused significant activation of NLRP3 inflammasomes and neuroinflammation in C57BL/6 mice, whereas inhibiting these effects through specific NLRP3 inflammasome blocker MCC950 (5 mg/kg) intervention or NLRP3 knock-out significantly ameliorated AA-induced ataxia, cerebellar Purkinje cells degeneration, and apoptosis. Furthermore, we demonstrated that antagonism of NLRP3 could also up-regulate the Nrf2 signalling pathway and related antioxidant genes. In conclusion, our findings indicate that activation of the NLRP3 inflammasome pathway is involved in AA-induced neurotoxicity, whereas MCC950 treatment or NLRP3 knock-out could effectively protect against AA-induced neurotoxic injury through the inhibition of neuroinflammation and activation of the Nrf2 antioxidant pathway. Therefore, the NLRP3 inflammasome might serve as a promising therapeutic target, with drugs designed to specifically inhibit this pathway potentially providing new avenues for preventing or ameliorating AA poisoning.

Mining the proliferative diabetic retinopathy-associated genes and pathways by integrated bioinformatic analysis

PURPOSE

Diabetic retinopathy (DR) especially proliferative diabetic retinopathy (PDR) is a serious eye disease. We aimed to identify key pathway and hub genes associated with PDR by analyzing the expression of retinal fibrovascular tissue in PDR patients.

METHODS

First raw data were downloaded from the Gene Expression Omnibus database. Median normalization was subsequently applied to preprocess. Differentially expressed genes (DEGs) analyzed with the Limma package. Weighted correlation network analysis (WGCNA) was utilized to build the co-expression network for all genes. Then, we compared the DEGs and modules filtered out by WGCNA. A protein-protein interaction network based on the STRING web site and the Cytoscape software was constructed by the overlapping DEGs. Next, the Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed. Finally, we used the Comparative Toxicogenomics Database to identify some important pathways and hub genes tightly related to PDR.

RESULTS

Functional enrichment analysis showed that the pathway of cytokine-cytokine receptor interaction was significantly related to PDR eight hub genes which were associated with pathway including tumor necrosis factor (TNF), tumor necrosis factor receptor superfamily member 12A (TNFRSF12A), C-C chemokine 20 (CCL20), chemokine (C-X-C motif) ligand 2 (CXCL2), oncostatin M (OSM) interleukin 10 (IL10), interleukin 15 (IL 15), and interleukin 1B (IL1B).

CONCLUSIONS

We identified one pathway and eight hub genes, which were associated with PDR. The pathway provided references that will advance the understanding of mechanisms of PDR. Moreover, the hub genes may serve as therapeutic targets for precise diagnosis and treatment of PDR in the future.

Mitochondrial DNA Promotes NLRP3 Inflammasome Activation and Contributes to Endothelial Dysfunction and Inflammation in Type 1 Diabetes

Background: NLRP3 inflammasome activation in response to several signals, including mitochondrial DNA (mDNA), regulates inflammatory responses by caspase-1 activation and interleukin-1β (IL-1β) release. Circulating mDNA is linked to micro and macrovascular complications in diabetes. However, a role for mDNA in endothelial dysfunction is not clear. We tested the hypothesis that mDNA contributes to diabetes-associated endothelial dysfunction and vascular inflammation via NLRP3 activation. Methods: Vascular reactivity, reactive oxygen species (ROS) generation, calcium (Ca²⁺) influx and caspase-1 and IL-1β activation were determined in mesenteric resistance arteries from normoglicemic and streptozotocin-induced diabetic C57BL/6 and NLRP3 knockout (Nlrp3^-/- ) mice. Endothelial cells and mesenteric arteries were stimulated with mDNA from control (cmDNA) and diabetic (dmDNA) mice. Results: Diabetes reduced endothelium-dependent vasodilation and increased vascular ROS generation and caspase-1 and IL-1β activation in C57BL/6, but not in Nlrp3^-/- mice. Diabetes increased pancreatic cytosolic mDNA. dmDNA decreased endothelium-dependent vasodilation. In endothelial cells, dmDNA activated NLRP3 via mitochondrial ROS and Ca²⁺ influx. Patients with type 1 diabetes exhibited increased circulating mDNA as well as caspase-1 and IL-1β activation. Conclusion: dmDNA activates endothelial NLRP3 inflammasome by mechanisms that involve Ca²⁺ influx and mitochondrial ROS generation. NLRP3 deficiency prevents diabetes-associated vascular inflammatory damage and endothelial dysfunction. Our study highlights the importance of NLRP3 inflammasome in diabetes-associated vascular dysfunction, which is key to diabetic complications.

Interleukin-38 is elevated in inflammatory bowel diseases and suppresses intestinal inflammation

There has been no report investigating the role of IL-38 in inflammatory bowel diseases (IBD). Therefore, we investigated the expression of IL-38 in IBD patients and its role in regulating intestinal inflammation. The levels of IL-38 were significantly elevated in the intestine of IBD patients and DSS-induced colitis mice. Immunofluorescence analysis revealed that B cell, not macrophage or T cell, was the source of IL-38 in the intestine. We found that rIL-38 treatment significantly attenuated DSS-induced colitis, including alleviation of weight loss, disease activity index, macroscopic changes and histological damage of colon, along with lower levels of IL-1β and TNF-α. In vitro, rIL-38 significantly decreased the expression of proinflammatory cytokines in LPS-stimulated RAW 264.7 cells and BMDM. This is the first study suggesting that IL-38 may have a protective effect in IBD, which inhibits the production of proinflammatory cytokines from macrophages. IL-38 may represent a promising therapeutic strategy in IBD.

Autologous Microfragmented Adipose Tissue Reduces the Catabolic and Fibrosis Response in an In Vitro Model of Tendon Cell Inflammation

Background

Mesenchymal stem cells (MSCs) emerged as a promising therapy for tendon pathologies. Microfragmented adipose tissue (μFAT) represents a convenient autologous product for the application of MSC-based therapies in the clinical setting. In the present study, the ability of μFAT to counteract inflammatory processes induced by IL-1β on human tendon cells (TCs) was evaluated.

Methods

Cell viability and proliferation were evaluated after 48 hours of transwell coculture of TCs and autologous μFAT in the presence or absence of IL-1β. Gene expression of scleraxis, collagen type I and type III, metalloproteinases-1 and -3, and cyclooxygenase-2 was evaluated by real-time RT-PCR. The content of VEGF, IL-1Ra, TNFα, and IL-6 was evaluated by ELISA.

Results

IL-1β-treated TCs showed augmented collagen type III, metalloproteases, and cyclooxygenase-2 expression. μFAT was able to reduce the expression of collagen type III and metalloproteases-1 in a significant manner, and at the same time, it enhanced the production of VEGF, IL-1Ra, and IL-6.

Conclusions

In this in vitro model of tendon cell inflammation, the paracrine action of μFAT, exerted by anti-inflammatory molecules and growth factors, was able to inhibit the expression of fibrosis and catabolic markers. Then, these results suggest that the application of μFAT may represent an effective conservative or adjuvant therapy for the treatment of tendon disorders.

Function and Regulation of IL-36 Signaling in Inflammatory Diseases and Cancer Development

The IL-36 subfamily of cytokines belongs to the IL-1 superfamily and consists of three pro-inflammatory agonists IL-36α, IL-36β, IL-36γ, and an IL-36 receptor (IL-36R) antagonist, IL-36Ra. These IL-36 cytokines function through a common receptor to modulate innate and adaptive immune responses. IL-36 cytokines are expressed as inactive precursors and require proteolytic processing to become fully active. Upon binding to IL-36R, IL-36 agonists augment the expression and production of inflammatory cytokines via activating signaling pathways. IL-36 is mainly expressed in epidermal, bronchial, and intestinal epithelial cells that form the barrier structures of the body and regulates the balance between pro-inflammatory and anti-inflammatory cytokine production at these tissue sites. Dysregulation of IL-36 signaling is a major etiological factor in the development of autoimmune and inflammatory diseases. Besides its critical role in inflammatory skin diseases such as psoriasis, emerging evidence suggests that aberrant IL-36 activities also promote inflammatory diseases in the lung, kidneys, and intestines, underscoring the potential of IL-36 as a therapeutic target for common inflammatory diseases. The role of IL-36 signaling in cancer development is also under investigation, with limited studies suggesting a potential anti-tumor effect. In this comprehensive review, we summarize current knowledge regarding the expression, activation, regulatory mechanisms, and biological functions of IL-36 signaling in immunity, inflammatory diseases, and cancer development.

Interleukin-38 interacts with destrin/actin-depolymerizing factor in human keratinocytes

Interleukin (IL)-38 is a member of the IL-1 family of cytokines, which was proposed to exert anti-inflammatory effects. IL-38 is constitutively expressed in the skin, where keratinocytes are the main producing cells. Little information is currently available concerning IL-38 biology. Here, we investigated the subcellular localization and interaction partners of the IL-38 protein in human keratinocytes. IL-38 expression was reduced in primary keratinocytes grown in monolayer (2D) cultures. We thus used IL-38 overexpressing immortalized normal human keratinocytes (NHK/38) to study this cytokine in cell monolayers. In parallel, differentiation of primary human keratinocytes in an in vitro reconstructed human epidermis (RHE) 3D model allowed us to restore endogenous IL-38 expression. In NHK/38 cells and in RHE, IL-38 was mainly cell-associated, rather than released into culture supernatants. Intracellular IL-38 was preferentially, although not exclusively, cytoplasmic. Similarly, in normal human skin sections, IL-38 was predominantly cytoplasmic in the epidermis and essentially excluded from keratinocyte nuclei. A yeast two-hybrid screen identified destrin/actin-depolymerizing factor (DSTN) as a potential IL-38-interacting molecule. Co-immunoprecipitation and proximity ligation assay confirmed this interaction. We further observed partial co-localization of IL-38 and DSTN in NHK/38 cells. Endogenous IL-38 and DSTN were also co-expressed in all epidermal layers in RHE and in normal human skin. Finally, IL-38 partially co-localized with F-actin in NHK/38 cells, in particular along the cortical actin network and in filopodia. In conclusion, IL-38 is found predominantly in the cytoplasm of human keratinocytes, where it interacts with DSTN. The functional relevance of this interaction remains to be investigated.

Icariin Alleviates IL-1β-Induced Matrix Degradation By Activating The Nrf2/ARE Pathway In Human Chondrocytes

Objective

Osteoarthritis (OA) is characterized by progressive matrix destruction of articular cartilage. This study aimed to investigate the potential antioxidative and chondroprotective effects and underlying mechanism of Icariin (ICA) in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation of OA cartilage.

Methods

Human chondrocyte cell line HC-A was treated with different doses of ICA, and then MTT assay and PI staining were used to estimate ICA-induced chondrocyte apoptosis. Intracellular ROS and superoxide dismutase (SOD) and glutathione peroxidase (GPX) were measured after treatment by IL-1β with or without ICA. The mRNA and protein expression levels of redox transcription factor Nrf2 and the downstream effector SOD-1, SOD-2, NQO-1 and HO-1 were assayed to explore the detailed mechanism by which ICA alleviates ECM degradation. Finally, to expound the role of Nrf2 in ICA-mediated chondroprotection, we specifically depleted Nrf2 in human chondrocytes and then pretreated them with ICA followed by IL-1β.

Results

ICA had no cytotoxic effects on human chondrocytes and 10⁻⁹ M was selected as the optimum concentration. ROS induced by IL-1β could drastically activate matrix-degrading proteases and ICA could significantly rescue the matrix degradation and excess ROS generation caused by IL-1β. We observed that ICA activated the Nrf2/ARE pathway, consequently upregulating the generation of GPX and SOD. Ablation of Nrf2 abrogated the chondroprotective and antioxidative effects of ICA in IL-1β-treated chondrocytes.

Conclusion

ICA alleviates IL-1β-induced matrix degradation and eliminates ROS by activating the Nrf2/ARE pathway.

Interleukin-38 alleviates cardiac remodelling after myocardial infarction

Excessive immune‐mediated inflammatory reaction plays a deleterious role in ventricular remodelling after myocardial infarction (MI). Interleukin (IL)‐38 is a newly characterized cytokine of the IL‐1 family and has been reported to exert a protective effect in some autoimmune diseases. However, its role in cardiac remodelling post‐MI remains unknown. In this study, we found that the expression of IL‐38 was increased in infarcted heart after MI induced in C57BL/6 mice by permanent ligation of the left anterior descending artery. In addition, our data showed that ventricular remodelling after MI was significantly ameliorated after recombinant IL‐38 injection in mice. This amelioration was demonstrated by better cardiac function, restricted inflammatory response, attenuated myocardial injury and decreased myocardial fibrosis. Our results in vitro revealed that IL‐38 affects the phenotype of dendritic cells (DCs) and IL‐38 plus troponin I (TNI)‐treated tolerogenic DCs dampened adaptive immune response when co‐cultured with CD4⁺T cells. In conclusion, IL‐38 plays a protective effect in ventricular remodelling post‐MI, one possibility by influencing DCs to attenuate inflammatory response. Therefore, targeting IL‐38 may hold a new therapeutic potential in treating MI.

Injury-Induced Effectors of Neuropathic Pain

Injuries typically result in the development of neuropathic pain, which decreases in parallel with wound healing. However, the pain may remain after the injury appears to have healed, which is generally associated with an ongoing underlying pro-inflammatory state. Injury induces many cells to release factors that contribute to the development of a pro-inflammatory state, which is considered an essential first step towards wound healing. However, pain elimination requires a transition of the injury site from pro- to anti-inflammatory. Therefore, developing techniques that eliminate chronic pain require an understanding of the cells resident at and recruited to injury sites, the factors they release, that promote a pro-inflammatory state, and promote the subsequent transition of that site to be anti-inflammatory. Although a relatively large number of cells, factors, and gene expression changes are involved in these processes, it may be possible to control a relatively small number of them leading to the reduction and elimination of chronic neuropathic pain. This first of two papers examines the roles of the most salient cells and mediators associated with the development and maintenance of chronic neuropathic pain. The following paper examines the cells and mediators involved in reducing and eliminating chronic neuropathic pain.

Advances in nanomedicine for the treatment of ankylosing spondylitis

Ankylosing spondylitis (AS) is a complex disease characterized by inflammation and ankylosis primarily at the cartilage–bone interface. The disease is more common in young males and risk factors include both genetic and environmental. While the pathogenesis of AS is not completely understood, it is thought to be an immune-mediated disease involving inflammatory cellular infiltrates, and human leukocyte antigen-B27. Currently, there is no specific diagnostic technique available for this disease; therefore conventional diagnostic approaches such as clinical symptoms, laboratory tests and imaging techniques are used. There are various review papers that have been published on conventional treatment approaches, and in this review work, we focus on the more promising nanomedicine-based treatment modalities to move this field forward.

Cytokines and serum amyloid A in the pathogenesis of hepatitis C virus infection

Expression of the acute phase protein serum amyloid A (SAA) is dependent on the release of the pro-inflammatory cytokines IL-1, IL-6 and TNF-α during infection and inflammation. Hepatitis C virus (HCV) upregulates SAA-inducing cytokines. In line with this, a segment of chronically infected individuals display increased circulating levels of SAA. SAA has even been proposed to be a potential biomarker to evaluate treatment efficiency and the course of disease. SAA possesses antiviral activity against HCV via direct interaction with the viral particle, but might also divert infectivity through its function as an apolipoprotein. On the other hand, SAA shares inflammatory and angiogenic activity with chemotactic cytokines by activating the G protein-coupled receptor, formyl peptide receptor 2. These latter properties might promote chronic inflammation and hepatic injury. Indeed, up to 80 % of infected individuals develop chronic disease because they cannot completely clear the infection, due to diversion of the immune response. In this review, we summarize the interconnection between SAA and cytokines in the context of HCV infection and highlight the dual role SAA could play in this disease. Nevertheless, more research is needed to establish whether the balance between those opposing activities can be tilted in favor of the host defense.

Co-inhibition of HDAC and MLL-menin interaction targets MLL-rearranged acute myeloid leukemia cells via disruption of DNA damage checkpoint and DNA repair

While the aberrant translocation of the mixed-lineage leukemia (MLL) gene drives pathogenesis of acute myeloid leukemia (AML), it represents an independent predictor for poor prognosis of adult AML patients. Thus, small molecule inhibitors targeting menin-MLL fusion protein interaction have been emerging for the treatment of MLL-rearranged AML. As both inhibitors of histone deacetylase (HDAC) and menin-MLL interaction target the transcription-regulatory machinery involving epigenetic regulation of chromatin remodeling that governs the expression of genes involved in tumorigenesis, we hypothesized that these two classes of agents might interact to kill MLL-rearranged (MLL-r) AML cells. Here, we report that the combination treatment with subtoxic doses of the HDAC inhibitor chidamide and the menin-MLL interaction inhibitor MI-3 displayed a highly synergistic anti-tumor activity against human MLL-r AML cells in vitro and in vivo, but not those without this genetic aberration. Mechanistically, co-exposure to chidamide and MI-3 led to robust apoptosis in MLL-r AML cells, in association with loss of mitochondrial membrane potential and a sharp increase in ROS generation. Combined treatment also disrupted DNA damage checkpoint at the level of CHK1 and CHK2 kinases, rather than their upstream kinases (ATR and ATM), as well as DNA repair likely via homologous recombination (HR), but not non-homologous end joining (NHEJ). Genome-wide RNAseq revealed gene expression alterations involving several potential signaling pathways (e.g., cell cycle, DNA repair, MAPK, NF-κB) that might account for or contribute to the mechanisms of action underlying anti-leukemia activity of chidamide and MI-3 as a single agent and particularly in combination in MLL-r AML. Collectively, these findings provide a preclinical basis for further clinical investigation of this novel targeted strategy combining HDAC and Menin-MLL interaction inhibitors to improve therapeutic outcomes in a subset of patients with poor-prognostic MLL-r leukemia.

Acute Respiratory Barrier Disruption by Ozone Exposure in Mice

Ozone exposure causes irritation, airway hyperreactivity (AHR), inflammation of the airways, and destruction of alveoli (emphysema), the gas exchange area of the lung in human and mice. This review focuses on the acute disruption of the respiratory epithelial barrier in mice. A single high dose ozone exposure (1 ppm for 1 h) causes first a break of the bronchiolar epithelium within 2 h with leak of serum proteins in the broncho-alveolar space, disruption of epithelial tight junctions and cell death, which is followed at 6 h by ROS activation, AHR, myeloid cell recruitment, and remodeling. High ROS levels activate a novel PGAM5 phosphatase dependent cell-death pathway, called oxeiptosis. Bronchiolar cell wall damage and inflammation upon a single ozone exposure are reversible. However, chronic ozone exposure leads to progressive and irreversible loss of alveolar epithelial cells and alveoli with reduced gas exchange space known as emphysema. It is further associated with chronic inflammation and fibrosis of the lung, resembling other environmental pollutants and cigarette smoke in pathogenesis of asthma, and chronic obstructive pulmonary disease (COPD). Here, we review recent data on the mechanisms of ozone induced injury on the different cell types and pathways with a focus on the role of the IL-1 family cytokines and the related IL-33. The relation of chronic ozone exposure induced lung disease with asthma and COPD and the fact that ozone exacerbates asthma and COPD is emphasized.

Role of NLRP3 inflammasome in inflammatory bowel diseases

Inflammasomes are multiprotein intracellular complexes which are responsible for the activation of inflammatory responses. Among various subtypes of inflammasomes, NLRP3 has been a subject of intensive investigation. NLRP3 is considered to be a sensor of microbial and other danger signals and plays a crucial role in mucosal immune responses, promoting the maturation of proinflammatory cytokines interleukin 1β (IL-1β) and IL-18. NLRP3 inflammasome has been associated with a variety of inflammatory and autoimmune conditions, including inflammatory bowel diseases (IBD). The role of NLRP3 in IBD is not yet fully elucidated as it seems to demonstrate both pathogenic and protective effects. Studies have shown a relationship between genetic variants and mutations in NLRP3 gene with IBD pathogenesis. A complex interaction between the NLRP3 inflammasome and the mucosal immune response has been reported. Activation of the inflammasome is a key function mediated by the innate immune response and in parallel the signaling through IL-1β and IL-18 is implicated in adaptive immunity. Further research is needed to delineate the precise mechanisms of NLRP3 function in regulating immune responses. Targeting NLRP3 inflammasome and its downstream signaling will provide new insights into the development of future therapeutic strategies.

Audiometric notch for the prediction of early occupational hearing loss and its association with the interleukin-1beta genotype

Objectives

Noise-induced hearing loss (NIHL) is a frequent and irreversible industrial-health problem, the early diagnosis of which can prevent hearing deterioration, especially of speech frequencies. This study aimed to assess hearing impairment in workers occupationally exposed to noise. Audiometric notches and IL-1β gene polymorphisms were evaluated.

Methods

The study included 98 workers employed in a textile factory. Pure-tone audiometric testing was conducted for all workers, using a manual pure-tone diagnostic audiometer, and the noise level was measured at four different work sites in a spinning section. IL-1β gene polymorphism was determined using PCR-RFLP methods.

Results

Workers were exposed to a mean noise level of 105.5 dB. As many as 27.6% of them complained of tinnitus and the majority suffered from some degree of hearing loss in either ear, but none of them exceeded 60 dB. Audiometric notches were detected in either one or both ears. Only 28.6% of workers showed the absence of notches. The TT genotype of IL-1β polymorphisms was dominant in 49% of the workers, whereas TC was predominant in 39.8% and CC in 11.2%. The CC genotype was associated with smoking (54.5%) and audiometric notches (100%). The IL-1β genotype distribution showed no significant difference with or without tinnitus.

Conclusion

This study showed an association between the CC genotype and smoking as well as audiometric notches in workers occupationally exposed to noise. Workers showing audiometric notches should be followed up regularly. Further studies are required to confirm the interrelationship amongst tinnitus, audiometric notches, and IL-1β genotypes.

Detection of IL-18 and IL-1β protein and mRNA in human oral epithelial cells induced by Campylobacter concisus strains

Campylobacter concisus is an emerging bacterial pathogen that may play a role in the development of inflammatory bowel disease and oral inflammatory conditions such as periodontal disease. To elucidate the role and pathogenic mechanisms of C. concisus in contributing to oral inflammation, this study examined the production of IL-1 family proinflammatory cytokines IL-18 and IL-1β in oral epithelial cells induced by C. concisus strains using enzyme-linked immunosorbent assay (ELISA), Western-blot and quantitative real-time PCR. C. concisus increased the mRNA levels of IL-18 and IL-1β in oral epithelial cells. Furthermore, a large amount of IL-18 in the supernatants of oral epithelial cells infected with C. concisus strains was detected by ELISA, and various experiments demonstrated that this positive signal was derived from C. concisus bacterium. The findings that C. concisus upregulated IL-18 and IL-1β in oral epithelial cells from this study support a role of C. concisus in oral inflammatory diseases. Furthermore, the finding that C. concisus released a molecule that was strongly cross-reactive to anti-human IL-18 monoclonal antibodies suggests that in future studies examining cytokines induced by bacterial microbes, a bacterium control should be included.

Pulmonary fibroblasts-secreted CXCL10 polarizes alveolar macrophages under pro-inflammatory stimuli

BACKGROUND

During acute lung injury, lung fibroblasts produce chemokines that assist the activation and migration of resident macrophages. The interactions between pulmonary fibroblasts and alveolar macrophages demonstrate the early event in the recruitment of immune cells, and the production of chemokines appear to be central mediators of the initiation and progression of inflammatory responses. In this study, the aim was to investigate the signaling pathway leading to CXCL10 secretion and the effects of CXCL10 released by activated fibroblasts on regulating macrophage polarization in a pro-inflammatory microenvironment.

METHODS

The expression of chemokines CCL2, CCL5, CXCL10, and CXCL12, and the phosphorylation of signaling molecules STAT3, FAK, GSK3αβ and PKCδ were investigated by real time-PCR, ELISA, or Western blot on TNFα- or IL-1β-activated MRC-5 pulmonary fibroblasts. By collecting conditioned medium from TNFα-activated fibroblasts, the expression of iNOS and arginase I on MH-S alveolar macrophages were examined by real-time PCR. Surface markers CD86 and CD206 expressions on alveolar macrophages were also evaluated by flow cytometry.

RESULTS

We found that CXCL10 production was significantly elevated on MRC-5 fibroblasts under TNFα- or IL-1β treatment. In addition, we revealed that TNFα and IL-1β initiated phosphorylation of STAT3, FAK, GSK3αβ and PKCδ signaling cascade, leading to the elevation of CXCL10 expression. Moreover, conditioned medium collected from TNFα-activated MRC-5 fibroblasts increased iNOS and CD86 expressions and decreased arginase I and CD206 expressions on MH-S alveolar macrophages, and neutralization of CXCL10 abolished these observed phenomena.

CONCLUSION

These results suggest that CXCL10 is crucial in activated fibroblasts-promoted M1 phenotype polarization of alveolar macrophages. In this regard, targeting fibroblasts-released CXCL10 may be promising as anti-inflammatory therapy against acute lung injury.

Epithelial origin of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory disease of the esophagus characterized predominantly by eosinophilic inflammation, leading to esophageal dysfunction. Converging data have placed the esophageal epithelium at the center of disease pathogenesis. In particular, the main EoE disease susceptibility loci at 2p23 and 5p22 encode for gene products that are produced by the esophageal epithelium: the intracellular protease calpain 14 and thymic stromal lymphopoietin, respectively. Furthermore, genetic and functional data establish a primary role for impaired epithelial barrier function in disease susceptibility and pathoetiology. Additionally, the EoE transcriptome, a set of genes dysregulated in the esophagi of patients with EoE, is enriched in genes that encode for proteins involved in esophageal epithelial cell differentiation. This transcriptome has a high proportion of esophagus-specific epithelial genes that are notable for the unexpected enrichment in genes encoding for proteases and protease inhibitors, as well as in IL-1 family genes, demonstrating a previously unappreciated role for innate immunity responses in the esophagus under homeostatic conditions. Among these pathways, basal production of the serine protease inhibitor, Kazal-type 7 (SPINK7) has been demonstrated to be part of the normal differentiation program of esophageal epithelium. Profound lost expression of SPINK7 occurs in patients with EoE and is sufficient for unleashing increased proteolytic activity (including urokinase plasminogen activator), impaired barrier function, and production of large quantities of proinflammatory and proallergic cytokines, including thymic stromal lymphopoietin. Collectively, we put forth a model in which the esophagus is normally equipped as an anti-inflammatory sensing organ and that defects in this pathway, mediated by epithelial protease/protease inhibitor imbalances, unleash inflammatory responses resulting in disorders, such as EoE.

Platelets and Immune Responses During Thromboinflammation

Besides mediating hemostatic functions, platelets are increasingly recognized as important players of inflammation. Data from experiments in mice and men revealed various intersection points between thrombosis, hemostasis, and inflammation, which are addressed and discussed in this review in detail. One such example is the intrinsic coagulation cascade that is initiated after platelet activation thereby further propagating and re-enforcing wound healing or thrombus formation but also contributing to the pathophysiology of severe diseases. FXII of the intrinsic pathway connects platelet activation with the coagulation cascade during immune reactions. It can activate the contact system thereby either creating an inflammatory state or accelerating inflammation. Recent insights into platelet biology could show that platelets are equipped with complement receptors. Platelets are important for tissue remodeling after injury has been inflicted to the endothelial barrier and to the subendothelial tissue. Thus, platelets are increasingly recognized as more than just cells relevant for bleeding arrest. Future insights into platelet biology are to be expected. This research will potentially offer novel opportunities for therapeutic intervention in diseases featuring platelet abundance.

Interleukin-1 receptor antagonist treatment in acute ischaemic stroke does not alter systemic markers of anti-microbial defence

Background: Blockade of the cytokine interleukin-1 (IL-1) with IL-1 receptor antagonist (IL-1Ra) is a candidate treatment for stroke entering phase II/III trials, which acts by inhibiting harmful inflammatory responses.  Infection is a common complication after stroke that significantly worsens outcome and is related to stroke-induced deficits in systemic immune function thought to be mediated by the sympathetic nervous system.  Therefore, immunomodulatory treatments for stroke, such as IL-1Ra, carry a risk of aggravating stroke-associated infection. Our primary objective was to determine if factors associated with antibody-mediated antibacterial defences were further compromised in patients treated with IL-1Ra after stroke. Methods: We assessed plasma concentrations of immunoglobulin isotypes and complement components in stroke patients treated with IL-1Ra or placebo and untreated non-stroke controls using multiplex protein assays. Activation of the sympathetic nervous system (SNS) was determined by measuring noradrenaline, a major SNS mediator. Results:  There were significantly lower plasma concentrations of IgM, IgA, IgG1 and IgG4 in stroke-patients compared to non-stroke controls, however there were no differences between stroke patients treated with placebo or IL-1Ra. Concentrations of complement components associated with the classical pathway  were increased and those associated with the alternative pathways decreased in stroke patients, neither being affected by treatment with IL-1Ra.  Noradrenaline concentrations were increased after stroke in both placebo and IL-1Ra-treated stroke patients compared to non-stroke controls.  Conclusion: These data show treatment with IL-1Ra after stroke does not alter circulating immunoglobulin and complement concentrations and is therefore unlikely to further aggravate stroke-associated infection susceptibility through altered availability of these key anti-microbial mediators.

Interleukin-1 receptor antagonist treatment in acute ischaemic stroke does not alter systemic markers of anti-microbial defence

Background: Blockade of the cytokine interleukin-1 (IL-1) with IL-1 receptor antagonist (IL-1Ra) is a candidate treatment for stroke entering phase II/III trials, which acts by inhibiting harmful inflammatory responses.  Infection is a common complication after stroke that significantly worsens outcome and is related to stroke-induced deficits in systemic immune function thought to be mediated by the sympathetic nervous system.  Therefore, immunomodulatory treatments for stroke, such as IL-1Ra, carry a risk of aggravating stroke-associated infection. Our primary objective was to determine if factors associated with antibody-mediated antibacterial defences were further compromised in patients treated with IL-1Ra after stroke. Methods: We assessed plasma concentrations of immunoglobulin isotypes and complement components in stroke patients treated with IL-1Ra or placebo and untreated non-stroke controls using multiplex protein assays. Activation of the sympathetic nervous system (SNS) was determined by measuring noradrenaline, a major SNS mediator. Results:  There were significantly lower plasma concentrations of IgM, IgA, IgG1 and IgG4 in stroke-patients compared to non-stroke controls, however there were no differences between stroke patients treated with placebo or IL-1Ra. Concentrations of complement components associated with the classical pathway  were increased and those associated with the alternative pathways decreased in stroke patients, neither being affected by treatment with IL-1Ra.  Noradrenaline concentrations were increased after stroke in both placebo and IL-1Ra-treated stroke patients compared to non-stroke controls.  Conclusion: These data show treatment with IL-1Ra after stroke does not alter circulating immunoglobulin and complement concentrations and is therefore unlikely to further aggravate stroke-associated infection susceptibility through reduced availability of these key anti-microbial mediators.

Acute elevation of serum inflammatory markers predicts symptom recovery after concussion

OBJECTIVE

To test the hypothesis that acute elevations in serum inflammatory markers predict symptom recovery after sport-related concussion (SRC).

METHODS

High school and collegiate football players (n = 857) were prospectively enrolled. Forty-one athletes with concussion and 43 matched control athletes met inclusion criteria. Serum levels of interleukin (IL)-6, IL-1β, IL-10, tumor necrosis factor, C-reactive protein, interferon-γ, and IL-1 receptor antagonist and Sport Concussion Assessment Tool, 3rd edition (SCAT3) symptom severity scores were collected at a preinjury baseline, 6 and 24-48 hours postinjury, and approximately 8, 15, and 45 days following concussion. The number of days that athletes were symptomatic following SRC (i.e., duration of symptoms) was the primary outcome variable.

RESULTS

IL-6 and IL-1RA were significantly elevated in athletes with concussion at 6 hours relative to preinjury and other postinjury visits, as well as compared to controls (ps ≤ 0.001). IL-6 and IL-1RA significantly discriminated concussed from control athletes at 6 hours postconcussion (IL-6 area under receiver operating characteristic curve 0.79 [95% confidence interval (CI) 0.65-0.92], IL-1RA AUC 0.79 [95% CI 0.67-0.90]). Further, IL-6 levels at 6 hours postconcussion were significantly associated with the duration of symptoms (hazard ratio for symptom recovery = 0.61 [95% CI 0.38-0.96], p = 0.031).

CONCLUSIONS

Results support the potential utility of IL-6 and IL-1RA as serum biomarkers of SRC and demonstrate the potential of these markers in identifying athletes at risk for prolonged recovery after SRC.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that serum levels of IL-6 and IL-1RA 6 hours postconcussion significantly discriminated concussed from control athletes.

Functional Relevance of Interleukin-1 Receptor Inter-domain Flexibility for Cytokine Binding and Signaling

The interleukin 1 (IL-1) receptor family, whose members contain three immunoglobulin-like domains (D1-D3) in the extracellular region, is responsible for transmitting pleiotropic signals of IL-1 cytokines. The inter-domain flexibility of IL-1 receptors and its functional roles have not been fully elucidated. In this study, we used small-angle X-ray scattering to show that ligand-binding primary receptors and co-receptors in the family all have inherent inter-domain flexibility due to the D2/D3 linker. Variants of the IL-1RAcP and IL-18Rβ co-receptors with mutated D2/D3 linkers cannot form a cytokine-receptor complex and mediate signaling. Our analysis further revealed that these mutated co-receptors exhibited a changed conformational ensemble, suggesting that loss of function is due to the alteration of receptor dynamics. Taken together, our results demonstrate that the D2/D3 linker is a critical functional determinant of IL-1 receptor and underscore the important roles of the inter-domain flexibility in cytokine/receptor binding and signaling.

Divergent Roles for the IL-1 Family in Gastrointestinal Homeostasis and Inflammation

Inflammatory disorders of the gastro-intestinal tract are a major cause of morbidity and significant burden from a health and economic perspective in industrialized countries. While the incidence of such conditions has a strong environmental component, in particular dietary composition, epidemiological studies have identified specific hereditary mutations which result in disequilibrium between pro- and anti-inflammatory factors. The IL-1 super-family of cytokines and receptors is highly pleiotropic and plays a fundamental role in the pathogenesis of several auto-inflammatory conditions including rheumatoid arthritis, multiple sclerosis and psoriasis. However, the role of this super-family in the etiology of inflammatory bowel diseases remains incompletely resolved despite extensive research. Herein, we highlight the currently accepted paradigms as they pertain to specific IL-1 family members and focus on some recently described non-classical roles for these pathways in the gastrointestinal tract. Finally, we address some of the shortcomings and sources of variance in the field which to date have yielded several conflicting results from similar studies and discuss the potential effect of these factors on data interpretation.

P2X7 receptor: A potential therapeutic target for autoimmune diseases

P2X7 receptor (P2X7R), a distinct ligand-gated ion channel, is a member of purinergic type 2 receptor family with ubiquitous expression in human body. Previous studies have revealed a pivotal role of P2X7R in innate and adaptive immunity. Once activated, it will meditate some vital cascaded responses including the assembly of nucleotide-binding domain (NOD) like receptor protein 3 (NLRP3) inflammasome, non-classical secretion of IL-1β, modulation of cytokine-independent pathways in inflammation such as P2X7R- transglutaminase-2 (TG2) and P2X7R-cathepsin pathway, activation and regulation of T cells, etc. In fact, above responses have been identified to be involved in the development of autoimmunity, specifically, the NLRP3 inflammasome could promote inflammation in massive autoimmune diseases and TG2, as well as cathepsin may contribute to joint destruction and degeneration in inflammatory arthritis. Recently, numerous evidences further suggested the significance of P2X7R in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), multiple sclerosis (MS), etc. In this review, we will succinctly discuss the biological characteristics and summarize the recent progress of the involvement of P2X7R in the development and pathogenesis of autoimmune diseases, as well as its clinical implications and therapeutic potential.

β Cell-Specific Deletion of the IL-1 Receptor Antagonist Impairs β Cell Proliferation and Insulin Secretion

Interleukin-1 receptor antagonist (IL-1Ra) is elevated in the circulation during obesity and type 2 diabetes (T2D) but is decreased in islets from patients with T2D. The protective role of local IL-1Ra was investigated in pancreatic islet β cell (βIL-1Ra)-specific versus myeloid-cell (myeloIL-1Ra)-specific IL-1Ra knockout (KO) mice. Deletion of IL-1Ra in β cells, but not in myeloid cells, resulted in diminished islet IL-1Ra expression. Myeloid cells were not the main source of circulating IL-1Ra in obesity. βIL-1Ra KO mice had impaired insulin secretion, reduced β cell proliferation, and decreased expression of islet proliferation genes, along with impaired glucose tolerance. The key cell-cycle regulator E2F1 partly reversed IL-1β-mediated inhibition of potassium channel Kir6.2 expression and rescued impaired insulin secretion in IL-1Ra knockout islets. Our findings provide evidence for the importance of β cell-derived IL-1Ra for the local defense of β cells to maintain normal function and proliferation.

Activated T-effector seeds: cultivating atherosclerotic plaque through alternative activation

Atherosclerosis is a chronic inflammatory pathology that precipitates substantial morbidity and mortality. Although initiated by physiological patterns of low and disturbed flow that differentially prime endothelial cells at sites of vessel branch points and curvature, the chronic, smoldering inflammation of atherosclerosis is accelerated by comorbidities involving inappropriate activation of the adaptive immune system, such as autoimmunity. The innate contributions to atherosclerosis, especially in the transition of monocyte to lipid-laden macrophage, are well established, but the mechanisms underpinning the infiltration, persistence, and effector dynamics of CD8 T cells in particular are not well understood. Adaptive immunity is centered on a classical cascade of antigen recognition and activation, costimulation, and effector cytokine secretion upon recall of antigen. However, chronic inflammation can generate alternative cues that supplant this behavior pattern and promote the retention and activation of peripherally activated T cells. Furthermore, the atherogenic foci that activated immune cell infiltrate are unique lipid-laden environments that offer a diverse array of stimuli, including those of survival, antigen hyporesponsiveness, and inflammatory cytokine expression. This review will focus on how known cardiovascular comorbidities may be influencing CD8 T-cell activation and how, once infiltrated within atherogenic foci, these T cells face a multitude of cues that skew the classical cascade of T-cell behavior, highlighting alternative modes of activation that may help contextualize associations of autoimmunity, viral infection, and immunotherapy with cardiovascular morbidity.

Safety and efficacy of hydroxytyrosol-based formulation on skin inflammation: in vitro evaluation on reconstructed human epidermis model

BACKGROUND

Atopic dermatitis is a multifactorial immune-mediated skin disorder characterized by an alteration of epidermal barrier function and onset of skin lesions, which range from mild erythema to severe lichenification. Treatment consists in hydration with possible use of topical or immunomodulatory corticosteroids, which, however sometimes showed side effects. Recently, the interest in natural compounds has grown significantly and among these, hydroxytyrosol (HT) plays a pivotal role due to its strong and well-known anti-inflammatory activity.

OBJECTIVES

The aim of this study was to investigate the safety and efficacy of Fenolia® Eudermal Cream 15 (HT-based formulation) on epidermal barrier impaired as consequence of skin injury.

METHODS

Whit this purpose, morphologic and structural as well as anti-inflammatory evaluations, after treatment with pro-inflammatory mediators (PBS 1 X and LPS) and HT-based formulation on reconstructed human epidermis (RHE) were carried out by qualitative (hematoxylin/eosin- and immunostaining) and quantitative (MTT assay, IL-1α and IL-8 release by ELISA) techniques. Furthermore, HT absorption through the epidermal barrier was evaluated by RP-LC-DAD analysis.

RESULTS

A rise in the thickness of the epidermis as well as an appropriate maturation and protein expression (Loricrin, Fillagrin, E-Cadherin and Cytokeratins 5&6) were detected in treated RHE samples. In particular, the HT-based formulation was found to stimulate cell proliferation, as evidenced by the significant increase in Ki67 expression, which suggests the involvement of repair mechanisms, increasing epithelial regeneration and differentiation and improving the epidermal barrier effect. Furthermore, HT-based formulation showed a statistically significant anti-inflammatory activity by reducing both IL-1α and IL-8 release by RHE tissues, greater than the reference drug dexamethasone. Finally, excellent transcutaneous absorption values were found for HT, demonstrating how this new formulation increases the availability of the bioactive compound.

CONCLUSIONS

In light of these results, Fenolia® Eudermal Cream 15 could be an effective agent to counteract atopic dermatitis. Graphical abstract Safety and efficacy of hydroxytyrosol-based formulation on skin inflammation: in vitro evaluation on reconstructed human epidermis model.

Interleukin-36 in Infectious and Inflammatory Skin Diseases

Interleukin-36 (IL-36) comprises to a cytokine family consisting of four isoforms IL-36α, IL-36β, IL-36γ, and IL-36 receptor antagonist (IL-36 Ra). These IL-36 cytokines, in turn, belong to the IL-1 superfamily. The IL-36 receptor (IL-1R6) is functional as a heterodimer formed of IL-1R6 and IL-1 receptor accessory protein (IL-1RAcP). IL-36α, IL-36β, and IL-36γ are regarded as pro-inflammatory ligands and IL-36 Ra as well as IL-38 as anti-inflammatory ligands of IL-1R6. IL-36 cytokines are mainly expressed on the barrier sites of the body e.g., bronchial, intestinal, and dermal epithelium. One of their most important biological functions is the bridging of innate and adaptive immune responses. A disturbed balance between pro-inflammatory and anti-inflammatory branches easily leads to inflammation of the corresponding tissue. The most prominent example for an altered IL-36 expression is the spectrum of psoriasis. In addition to inflammatory dermatoses, IL-36 also seems to play a role in infectious dermatoses. Microbial triggers, especially Staphylococcus aureus infection, increase the production of pro-inflammatory IL-36 cytokines and initiate/promote the inflammation of skin lesions. Due to the discovery of IL-36 as an important immune mediator, it has already been possible to develop important diagnostic tools for dermatitis. Not only in the field of inflammatory skin diseases, but also in pulmonary and intestinal inflammation, there is evidence that IL-36 cytokines might have diagnostic and/or therapeutic relevance.

Particulate matter induces pro-inflammatory cytokines via phosphorylation of p38 MAPK possibly leading to dermal inflammaging

Particulate matter (PM) is known to have harmful effects on human health. Epidemiological studies have suggested that PM exposure is related to skin diseases and extrinsic skin ageing. However, the mechanisms by which PM affects skin are unclear. The aim of this study was to investigate the mechanism of action of PMs on epidermal inflammation and skin ageing using a co-culture of human keratinocytes (HaCaT) and fibroblasts (HDF). SRM 1648a (pmA) and 1649b (pmB), which mainly comprise heavy metals and polycyclic aromatic hydrocarbons, respectively, were used as reference PMs. Cytotoxic effects, activation of AhR, phosphorylation of p38 kinase and ROS generation were examined in PM-treated HaCaT cells. The phosphorylation of p38 MAPK induced by PMs was shown to be critically important for the increases in IL-1α and IL-1β expression. Moreover, the mRNA and protein expression levels of MMP1 and COX2 were markedly increased in HDF cells co-cultured with PM-treated HaCaT cells. In conclusion, PMs induce the expression of pro-inflammatory cytokines in keratinocytes via the p38 MAPK pathway, and these interleukins increase the expression of MMP1 and COX2 in HDF cells. These results suggest that PMs trigger skin ageing via p38 MAPK activation and interleukin secretion in epidermal keratinocytes.

Wedelolactone suppresses IL-1β maturation and neutrophil infiltration in Aspergillus fumigatus keratitis

PURPOSE

Wedelolactone, a chemical compound extracted from Wedelia calendulacea or Eclipta alba, has been reported to regulate key steps in inflammation. However, the effects of wedelolactone on fungal keratitis are not known. Hence, we aimed to characterize the impact of wedelolactone in Aspergillus fumigatus keratitis.

METHODS

Aspergillus fumigatus was used to establish an in vivo mouse model of fungal keratitis and an in vitro model of THP-1 macrophages. Mice and THP-1 macrophages were pre-treated with wedelolactone. Clinical evaluation, myeloperoxidase (MPO) assay, neutrophil staining, western blot and quantitative polymerase chain reaction (qRT-PCR) were used to assess the effect of wedelolactone on A. fumigatus infection. Therapeutic effect of natamycin treatment with or without wedelolactone was measured via slit lamp microscopy.

RESULTS

We confirmed that wedelolactone attenuated the infiltration of neutrophils and decreased MPO level at earlier time points in mice with A. fumigatus keratitis. Pre-treatment with wedelolactone decreased pro-inflammatory cytokine interleukin 1 beta (IL-1β) maturation by inhibiting caspase-1 activity. Combined with natamycin, wedelolactone protected corneal transparency in mouse with fungal keratitis.

CONCLUSION

Present findings indicated that wedelolactone reduced host immune responses by attenuating neutrophil recruitment and IL-1β maturation in Aspergillus fumigatus keratitis. Wedelolactone combined with an antifungal medicine could be a potential therapy for reducing lesion severity in fungal keratitis.

Potential Therapeutic Value of Interleukin 1b-targeted Strategies in Atherosclerotic Cardiovascular Disease

Clinical trials have unequivocally shown that cholesterol-lowering drugs decrease the risk of atherosclerotic cardiovascular disease in an exceptionally wide range of individuals. Yet, even when treated optimally according to current standards, many individuals still experience life-threatening ischemic events. Emerging experimental and clinical evidence strongly suggests that persistent inflammation is a major driver of this residual risk, which has opened the door to the application of anti-inflammatory drugs for cardiovascular disease prevention. Here, we review our current knowledge of the biology of interleukin-1β, a key regulator of inflammation in atherosclerotic plaque and the target of the first clinical trial to demonstrate that an anti-inflammatory drug can effectively reduce cardiovascular risk. We discuss the challenges faced by interleukin-1β inhibitors and other anti-inflammatory compounds in their translation to the clinical scenario, and identify other potential targets within this signaling pathway that hold promise in the cardiovascular setting.

IL-37- and IL-35/IL-37-Producing Plasma Cells in Chronic Periodontitis

Periodontitis is one of the most prevalent chronic inflammatory diseases and is induced by the interaction between oral microorganisms and the host immune system. Plasma cells are of special interest in chronic periodontitis (CP), as they represent ~50% of infiltrated immune cells in periodontal lesions. Plasma cells constitute the only known cell type capable of antibody production; however, recent evidence supports an emerging role for distinct sets of plasma cells in cytokine production. However, the presence of cytokine-producing plasma cells in CP is unknown. In this study, we used immunohistochemistry to detect significantly elevated levels of IL-35 and IL-37 (2 recently identified anti-inflammatory cytokines) in CP gingival tissue as compared with healthy tissue. Remarkably, we demonstrate that CD138⁺ CD38⁺ plasma cells are the major immune cell type in CP gingival tissues and that these cells produce IL-35 and IL-37. We used immunofluorescence and confocal microscopy analysis to identify a subset of plasma cells with robust cytoplasmic expression of IL-37-we denote this subset as IL-37-producing plasma cells (CD138⁺CD38⁺P_IL-37). Another subset of plasma cells coproduces IL-35 and IL-37 and is denoted as IL-37/IL-35-coproducing plasma cells (CD138⁺CD38⁺P_IL-35/IL-37). We determined that these 2 plasma cell subsets are IgG⁺plasma cells. Moreover, we show that human recombinant IL-35 and IL-37 exhibit a dose-dependent inhibition of osteoclast formation in vitro (~78.9% and 97.7% inhibition in 300 ng/mL of IL-35 and IL-37, respectively, P < 0.05). Overall, our findings suggest that P_IL-37 and P_IL-35/IL-37 exist as subsets of plasma cells in CP lesions and that these 2 new types of plasma cells may regulate periodontitis pathogenesis by inhibiting alveolar bone loss through directly blocking osteoclast formation. Importantly, these data suggest a novel role of plasma cells and offer potential new mechanistic and regulatory targets to be investigated in the context of periodontal health and disease.

Contribution of Infrapatellar Fat Pad and Synovial Membrane to Knee Osteoarthritis Pain

Osteoarthritis (OA) is the most common form of joint disease and a major cause of pain and disability in the adult population. Interestingly, there are patients with symptomatic OA displaying pain, while patients with asymptomatic OA that do not experience pain but show radiographic signs of joint damage. Pain is a complex experience integrating sensory, affective, and cognitive processes related to several peripheral and central nociceptive factors besides inflammation. During the last years, the role of infrapatellar fat pad (IFP), other than the synovial membrane, has been investigated as a potential source of pain in OA. Interestingly, new findings suggest that IFP and synovial membrane might act as a functional unit in OA pathogenesis and pain. The present review discuss the role of IFP and synovial membrane in the development of OA, with a particular focus on pain onset and the possible involved mediators that may play a role in OA pathology and pain mechanisms. Inflammation of IFP and synovial membrane may drive peripheral and central sensitization in KOA. Since sensitization is associated with pain severity in knee OA and may potentially contribute to the transition from acute to chronic, persistent pain in knee OA, preventing sensitization would be a potentially effective and novel means of preventing worsening of pain in knee OA.

Interleukin-10 inhibits interleukin-1β production and inflammasome activation of microglia in epileptic seizures

BACKGROUND

Microglia are important for secreting chemical mediators of inflammatory responses in the central nervous system. Interleukin (IL)-10 and IL-1β secreted by glial cells support neuronal functions, but the related mechanisms remain vague. Our goal was to demonstrate the efficacy of IL-10 in suppressing IL-1β and in inflammasome activation in mice with epileptic seizure based on an epileptic-seizure mouse model.

METHODS

In this study, mice in which epileptic seizures were induced by administering picrotoxin (PTX) were used as a case group, and mice injected with saline were employed as the control group. The expression of nucleic acids, cytokines, or signaling pathways was detected by reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), flow cytometry, and Western blotting.

RESULTS

Our results demonstrated that IL-10 inhibits IL-1β production through two distinct mechanisms: (1) Treatment with lipopolysaccharides (LPS) results in IL-10 overexpression in microglia and reduced NLRP3 inflammasome activity, thus inhibiting caspase-1-related IL-1β maturation; (2) next, autocrine IL-10 was found to subsequently promote signal transducer and activator of transcription-3 (STAT-3), reducing amounts of pro-IL-1β.

CONCLUSIONS

Our results indicate that IL-10 is potentially effective in the treatment of inflammation encephalopathy, and suggest the potential usefulness of IL-10 for treating autoimmune or inflammatory ailments.

Protection against nonalcoholic steatohepatitis through targeting IL-18 and IL-1alpha by luteolin

BACKGROUND

The management of nonalcoholic steatohepatitis (NASH) is still a crosstalk so the current study was designed to evaluate the effect of different luteolin doses on an experimental model of NASH and to elucidate novel anti-inflammatory pathways underlying its effect.

METHODS

Adult male Wistar rats (200-220 g; n = 60) were used. Rats were fed a high carbohydrate/high fat diet (˜ 30% carbohydrate and 42% fat) daily for 12 weeks to induce NASH. Luteolin (10, 25, 50 or 100 mg/kg/day) was administered as a suspension (10% w/v in 0.9% NaCl) using an oral gavage. Histopathological changes (necrosis, inflammation and steatosis) were evaluated. Biomarkers for liver function, lipid peroxidation, extracellular matrix deposition and anti-oxidant activity were measured. Levels of IFN-γ, TNF-α and IL-1α and IL-18 were measured.

RESULTS

Obtained results showed ability of luteolin to reduce activity of ALT and AST and to decrease levels of bilirubin, hyaluronic acid and malondialdehyde significantly (p <  0.05). Also, luteolin showed an anti-oxidant activity as indicated by the significant (p <  0.05) increase in reduced glutathione. Finally, a significant (p <  0.05) decrease in IFN-γ, TNF-α, IL-1α and IL-18 levels was observed most notably in groups that received high doses of luteolin (50 and 100 mg/kg).

CONCLUSIONS

Luteolin can protect against non-alcoholic steatohepatitis through targeting the pro-inflammatory IL-1 and Il-18 pathways in addition to an antioxidant effect.

Elevated serum IL-37 concentrations in patients with sepsis

To investigate the changes and significance of IL-37 in patients with sepsis.A total of 50 patients with sepsis between September 2016 and October 2017 at the intensive care unit (ICU) of the First Affiliated Hospital of Shihezi University School of Medicine were selected as the sepsis group, 30 age and sex-matched healthy controls were selected as the control group. The levels of IL-37 in serum were measured by enzyme-linked immunosorbent assay (ELISA) on day 1 and day 7 of the sepsis patients.The levels of serum IL-37 in the sepsis group on day 1 [(39.13 ± 34.35)pg/mL] were significantly higher than that in the control group [(23.75 ± 2.52)pg/mL] with significant difference (P <.05). The levels of IL-37 in the sepsis group after treatment [(30.57 ± 11.01)pg/mL] on day 7 were obviously lower than that before treatment without statisticaly difference (P >.05). A correlation analysis showed that the levels of serum IL-37 and IL-1β were positively correlated.The level of IL-37 observed in sepsis was found to correlate with the severity of the inflammatory reaction. IL-37 could be an important cytokine in the control of sepsis by suppressing the production of pro-inflammatory cytokines.

The IKK-binding domain of NEMO is an irregular coiled coil with a dynamic binding interface

NEMO is an essential component in the activation of the canonical NF-κB pathway and exerts its function by recruiting the IκB kinases (IKK) to the IKK complex. Inhibition of the NEMO/IKKs interaction is an attractive therapeutic paradigm for diseases related to NF-κB mis-regulation, but a difficult endeavor because of the extensive protein-protein interface. Here we report the high-resolution structure of the unbound IKKβ-binding domain of NEMO that will greatly facilitate the design of NEMO/IKK inhibitors. The structures of unbound NEMO show a closed conformation that partially occludes the three binding hot-spots and suggest a facile transition to an open state that can accommodate ligand binding. By fusing coiled-coil adaptors to the IKKβ-binding domain of NEMO, we succeeded in creating a protein with improved solution behavior, IKKβ-binding affinity and crystallization compatibility, which will enable the structural characterization of new NEMO/inhibitor complexes.