Signal transduction by tumor necrosis factor and gene regulation of the inflammatory cytokine interleukin-6

Chlorogenic acid ameliorates non-proliferative diabetic retinopathy via alleviating retinal inflammation through targeting TNFR1 in retinal endothelial cells

As a prominent complication of diabetes mellitus (DM) affecting microvasculature, diabetic retinopathy (DR) originates from blood-retinal barrier (BRB) damage. Natural polyphenolic compound chlorogenic acid (CGA) has already been reported to alleviate DR. This study delves into the concrete mechanism of the CGA-supplied protection against DR and elucidates its key target in retinal endothelial cells. DM in mice was induced using streptozotocin (STZ). CGA mitigated BRB dysfunction, leukocytes adhesion and the formation of acellular vessels in vivo. CGA suppressed retinal inflammation and the release of tumor necrosis factor-α (TNFα) by inhibiting nuclear factor kappa-B (NFκB). Furthermore, CGA reduced the TNFα-initiated adhesion of peripheral blood mononuclear cell (PBMC) to human retinal endothelial cell (HREC). CGA obviously decreased the TNFα-upregulated expression of vascular cell adhesion molecule-1 (VCAM1) and intercellular adhesion molecule-1 (ICAM1), and abrogated the TNFα-induced NFκB activation in HRECs. All these phenomena were reversed by overexpressing type 1 TNF receptor (TNFR1) in HRECs. The CGA-provided improvement on leukocytes adhesion and retinal inflammation was disappeared in mice injected with an endothelial-specific TNFR1 overexpression adeno-associated virus (AAV). CGA reduced the interaction between TNFα and TNFR1 through binding to TNFR1 in retinal endothelial cells. In summary, excepting reducing TNFα expression via inhibiting retinal inflammation, CGA also reduced the adhesion of leukocytes to retinal vessels through decreasing VCAM1 and ICAM1 expression via blocking the TNFα-initiated NFκB activation by targeting TNFR1 in retinal endothelial cells. All of those mitigated retinal inflammation, ultimately alleviating BRB breakdown in DR.

Bioavailability of the tumor necrosis factor alpha/regulated on activation, normal T cell expressed and secreted (RANTES) biosystem inside the gestational sac during the pre-immune stages of embryo development

OBJECTIVES

In-vivo studies of the bioavailability of major components of the tumor necrosis factor alpha (TNFα) biosystem inside the gestational sac during embryogenesis have not been reported. We sought to determine the concentration of TNFα, soluble (s) TNFα receptors (sTNFR1, sTNFR2), and RANTES in the primate extraembryonic celomic fluid (ECF).

METHODS

A validated timed-pregnant baboon animal model (N: 10) for experimental research in pregnancy was used to collect paired maternal blood and ECF samples in ongoing pregnancies. The concentrations (pg/dL) of TNFα, sTNFR1, sTNFR2, and RANTES were then determined by ELISA immunoassays.

RESULTS

All animals delivered at term healthy newborns. The differential concentration of TNFα, sTNFR1, sTNFR2, and RANTES between the maternal plasma and the ECF could be determined with ratios for TNFα (5.4), sTNFR2 (1.85) and RANTES (3.59) that contrasted with that of sTNFR1 (0.07), which favored the gestational sac compartment. No significant correlations were noted between maternal plasma and ECF TNFR1, sTNFR2 and RANTES. There was a trend for a correlation between TNFα in maternal plasma and ECF (R=0.74; p=0.07).

CONCLUSIONS

We report the physiological concentrations of TNFα, sTNFR1, sTNFR2, and RANTES in extraembryonic celomic fluid during embryogenesis in primates.

Interleukin-6 and tumor necrosis factor-α attenuate dopamine release in mice fed a high-fat diet, but not medium or low-fat diets

Chronic low-grade inflammation is associated with a state of diet-induced obesity that impacts systemic tissues and can cross the blood-brain barrier to act directly on the brain. The extent to which pro-inflammatory cytokines released in these conditions affect dopamine presynaptic neurotransmission has not been previously investigated. The purpose of this study was to examine how dopamine terminals are affected by pro-inflammatory cytokines, and to determine if dietary fat consumption potentiates cytokine effects on dopamine release and reuptake rate in the nucleus accumbens (NAc). Male and female C57BL/6J mice were fed high, medium, or low-fat diets (60%, 30%, or 10% total kcals from fat, respectively) for six weeks. Fast scan cyclic voltammetry (FSCV) was used to measure dopamine release and reuptake rate in the NAc core from ex vivo coronal brain slices. Electrically evoked dopamine release and the maximal rate of dopamine reuptake (Vmax) were significantly lower in mice fed the 30% and 60% high-fat diets compared to the 10% low-fat group (p < 0.05). IL-6 5 or 10 nM or TNFα 30 or 300 nM was added to artificial cerebrospinal fluid (aCSF) bathed over brain slices during FSCV. No effect on dopamine release or Vmax was observed with lower concentrations. However, 10 nM IL-6 and 300 nM TNFα significantly reduced dopamine release in the 60% fat group (p < 0.05). No effect of added cytokine was observed on Vmax. Overall, these data provide evidence that dietary fat increases neural responsiveness to cytokines, which may help inform comorbidities between diet-induced obesity and depression or other mood disorders.

Evaluation of the protective roles of alpha-lipoic acid supplementation on nanomaterial-induced toxicity: A meta-analysis of in vitro and in vivo studies

Extensive exposure to nanomaterials causes oxidative stress and inflammation in various organs and leads to an increased risk of adverse health outcomes; therefore, how to prevent the toxic effects are of great concern to human. Alpha-lipoic acid (ALA) has anti-oxidant and anti-inflammatory activities, suggesting it may be effective to prevent nanomaterial-induced toxicity. However, the results obtained in individual studies remained controversial. We aimed to comprehensively evaluate the effects of ALA supplementation on nanomaterial-induced toxicity by performing a meta-analysis. Databases of PubMed, EMBASE, and Cochrane Library were searched up to May 2022. STATA 15.0 software was used for statistical analysis. Twelve studies were included. Meta-analysis of eight in vivo studies showed ALA supplementation could exert significant effects on nanomaterial-induced oxidative stress (by reducing MDA, ROS and increasing GSH, CAT, GPx, and SOD), inflammation (by downregulating NO, IgG, TNF-α, IL-6, and CRP), apoptosis (by activation of pro-apoptotic caspase-3), DNA damage (by a reduction in the tail length) and organ damage (by a decrease in the liver biomarker ALT and increases in brain neuron biomarker AChE and heart biomarker CPK). Pooled analysis of four in vitro studies indicated ALA intervention increased cell viability, decreased ROS levels, inhibited cell apoptosis and chelated metal ions. Subgroup analyses revealed changing the levels of GSH, IL-6, and metal ions were the main protective mechanisms of ALA supplementation because they were not changed by any subgroup factors. In conclusion, ALA supplementation may represent a potential strategy for the prevention of the toxicity induced by nanomaterials.

The hormetic and hermetic role of IL-6

Interleukin-6 is a pleiotropic cytokine regulating different tissues and organs in diverse and sometimes discrepant ways. The dual and sometime hermetic nature of IL-6 action has been highlighted in several contexts and can be explained by the concept of hormesis, in which beneficial or toxic effects can be induced by the same molecule depending on the intensity, persistence, and nature of the stimulation. According with hormesis, a low and/or controlled IL-6 release is associated with anti-inflammatory, antioxidant, and pro-myogenic actions, whereas increased systemic levels of IL-6 can induce pro-inflammatory, pro-oxidant and pro-fibrotic responses. However, many aspects regarding the multifaceted action of IL-6 and the complex nature of its signal transduction remains to be fully elucidated. In this review we collect mechanistic insight into the molecular networks contributing to normal or pathologic changes during advancing age and in chronic diseases. We point out the involvement of IL-6 deregulation in aging-related diseases, dissecting the hormetic action of this key mediator in different tissues, with a special focus on skeletal muscle. Since IL-6 can act as an enhancer of detrimental factor associated with both aging and pathologic conditions, such as chronic inflammation and oxidative stress, this cytokine could represent a "Gerokine", a determinant of the switch from physiologic aging to age-related diseases.

Flipped Well-Plate Hanging-Drop Technique for Growing Three-Dimensional Tumors

Three-dimensional (3D) tumor culture techniques are gaining popularity as in vitro models of tumoral tissue analogues. Despite the widespread interest, need, and present-day effort, most of the 3D tumor culturing methodologies have not gone beyond the inventors’ laboratories. This, in turn, limits their applicability and standardization. In this study, we introduce a straightforward and user-friendly approach based on standard 96-well plates with basic amenities for growing 3D tumors in a scaffold-free/scaffold-based format. Hanging drop preparation can be easily employed by flipping a universal 96-well plate. The droplets of the medium generated by the well-plate flip (WPF) method can be easily modified to address various mechanisms and processes in cell biology, including cancer. To demonstrate the applicability and practicality of the conceived approach, we utilized human colorectal carcinoma cells (HCT116) to first show the generation of large scaffold-free 3D tumor spheroids over 1.5 mm in diameter in single-well plates. As a proof-of-concept, we also demonstrate matrix-assisted tumor culture techniques in advancing the broader use of 3D culture systems. The conceptualized WPF approach can be adapted for a range of applications in both basic and applied biological/engineering research.

Plasma Concentrations of Cytokines in Patients with Combined Hyperlipidemia and Atherosclerotic Plaque before Treatment Initiation—A Pilot Study

Background and Objectives: The formation and destabilization of atherosclerotic plaques is a complex process involving several proteins and cytokines. Interleukin 6 (IL-6), interleukin 18 (IL-18), and tumor necrosis factor (TNF-α) are examples of such cytokines. The goal of our research is to compare the concentrations of the above-mentioned indicators in the plasma of patients with verified high-risk atherosclerotic plaque to the plasma levels of healthy people before lipid lowering therapy. Materials and Methods: Patients with dyslipidemia who had the presence of unstable atherosclerotic plaque verified by ultrasonography were included in the study. The concentrations of IL-6, IL-18 and TNF-α in the plasma of these people were determined and compared with the concentrations of these cytokines in the plasma of the control group. Results: Levels of lipid panel, IL-6 and IL-18 were significantly lower in the group of healthy people than in the study group. Conclusions: The concentrations of IL-6 and IL-18 in the plasma of patients with ruptured plaque are higher than in the plasma of healthy people, suggesting that these cytokines as a panel might be used as new indicators of the presence of unstable atherosclerotic plaque.

Anticancer profile and anti-inflammatory effect of new N-(2-((4-(1,3-diphenyl-1H-pyrazol-4-yl)pyridine sulfonamide derivatives

A new series of N-(2-((4-(1,3-diphenyl-1H-pyrazol-4-yl)pyridine sulfonamide derivatives 11a-o were designed and synthesized based on our previous works. The new series was tested for its anticancer and anti-inflammatory effects. The anticancer profile of final target compounds was obtained by testing them over 60 cell lines belong to nine types of cancers. Compound 11c showed the highest percent inhibition, so its potency was measured over the most sensitive cell line to determine its IC₅₀ over each cell. In addition, compound 11c was tested over kinase panel to get its biological target(s). Compound 11c had strong activity over JNK1, JNK2, p38a and V600EBRAF. All final target compounds were tested against the four kinases to build a structure activity relationship. Compound 11c was subjected to cell cycle analysis to check at which phase is affected by 11c. The anti-inflammatory effect of final target compounds was screened by testing their ability to inhibit both nitric oxide release and prostaglandin E2 production on raw 264.7 macrophages in addition to test their cytotoxic effect on the same cells. Compound 11n showed the highest ability to inhibit prostaglandin E2 and all compound showed moderate to low activity regarding inhibition of nitric oxide release. Compound 11n was investigated for its ability to reduce Interleukin 6 and TNF-alpha. In addition, compound 11n was tested for its effect on induced Nitric oxide synthase (iNOS), and COX-2 mRNA expression level and its effect on nitric oxide synthase (iNOS), COX-1 and COX-2 protein levels where it showed selectivity for COX-2 compared to COX-1 and iNOS.

Alpha and beta adrenoceptors activate interleukin-6 transcription through different pathways in cultured astrocytes from rat spinal cord

In brain astrocytes, noradrenaline (NA) has been shown to up-regulate IL-6 production via β-adrenoceptors (ARs). However, the underlying intracellular mechanisms for this regulation are not clear, and it remains unknown whether α-ARs are involved. In this study, we investigated the AR-mediated regulation of IL-6 mRNA levels in the cultured astrocytes from rat spinal cord. NA, the α1-agonist phenylephrine, and the β-agonist isoproterenol increased IL-6 mRNA levels. The phenylephrine-induced IL-6 increase was accompanied by an increase in ERK phosphorylation, and these effects were blocked by inhibitors of PKC and ERK. The isoproterenol-induced IL-6 increase was accompanied by an increase in CREB phosphorylation, and these effects were blocked by a PKA inhibitor. Our results indicate that IL-6 increases by α1- and β-ARs are mediated via the PKC/ERK and cAMP/PKA/CREB pathways, respectively. Moreover, conditioned medium collected from astrocytes treated with the α2-AR agonist dexmedetomidine, increased IL-6 mRNA in other astrocytes. In this study, we elucidate that α1- and α2-ARs, in addition to β-ARs, promote IL-6 transcription through different pathways in spinal cord astrocytes.

Plasticity of Naturally Occurring Regulatory T Cells in Allergic Airway Disease Is Modulated by the Transcriptional Activity of Il-6

The impact of naturally occurring regulatory T cells (nTregs) on the suppression or induction of lung allergic responses in mice depends on the nuclear environment and the production of the pro-inflammatory cytokine interleukin 6 (IL-6). These activities were shown to be different in nTregs derived from wild-type (WT) and CD8-deficient mice (CD8^−/−), with increased IL-6 levels in nTregs from CD8^−/− mice in comparison to WT nTregs. Thus, identification of the molecular mechanisms regulating IL-6 production is critical to understanding the phenotypic plasticity of nTregs. Electrophoretic mobility shift assays (EMSA) were performed to determine transcription factor binding to four Il-6 promoter loci using nuclear extracts from nTregs of WT and CD8^−/− mice. Increased transcription factor binding for each of the Il-6 loci was identified in CD8^−/− compared to WT nTregs. The impact of transcription factor binding and a novel short tandem repeat (STR) on Il-6 promoter activity was analyzed by luciferase reporter assays. The Il-6 promoter regions closer to the transcription start site (TSS) were more relevant to the regulation of Il-6 depending on NF-κB, c-Fos, and SP and USF family members. Two Il-6 promoter loci were most critical for the inducibility by lipopolysaccharide (LPS) and tumor necrosis factor α (TNFα). A novel STR of variable length in the Il-6 promoter was identified with diverging prevalence in nTregs from WT or CD8^−/− mice. The predominant GT repeat in CD8^−/− nTregs revealed the highest luciferase activity. These novel regulatory mechanisms controlling the transcriptional regulation of the Il-6 promoter are proposed to contribute to nTregs plasticity and may be central to disease pathogenesis.

Design, synthesis and anti-inflammatory activity of imidazol-5-yl pyridine derivatives as p38α/MAPK14 inhibitor

P38α/MAPK14 is intracellular signalling regulator involved in biosynthesis of inflammatory mediator cytokines (TNF-α, IL-1, IL-6, and IL-1b), which induce the production of inflammatory proteins (iNOS, NF-kB, and COX-2). In this study, drug repurposing strategies were followed to repositioning of a series of B-RAF ^V600E imidazol-5-yl pyridine inhibitors to inhibit P38α kinase. A group 25 reported P38α kinase inhibitors were used to build a pharmacophore model for mapping the target compounds and proving their affinity for binding in P38α active site. Target compounds were evaluated for their potency against P38α kinase, compounds 11a and 11d were the most potent inhibitors (IC₅₀ = 47 nM and 45 nM, respectively). In addition, compound 11d effectively inhibited the production of proinflammatory cytokinesTNF-α, 1L-6, and 1L-1β in LPS-induced RAW 264.7 macrophages with IC₅₀ values of 78.03 nM, 17.6 µM and 82.15 nM, respectively. The target compounds were tested for their anti-inflammatory activity by detecting the reduction of Nitric oxide (NO) and prostaglandin (PGE2) production in LPS-stimulated RAW 264.7 macrophages. Compound 11d exhibited satisfied inhibitory activity of the production of PGE2 and NO with IC₅₀ values of 0.29 µM and 0.61 µM, respectively. Molecular dynamics simulations of the most potent inhibitor 11d were carried out to illustrate its conformational stability in the binding site of P38α kinase.

Recent Advances in Clinical Translation of Intra-Articular Osteoarthritis Drug Delivery Systems

Osteoarthritis (OA) is a degenerative disease of the joints and a leading cause of physical disability in adults. Intra-articular (IA) therapy is a popular treatment strategy for localized, single-joint OA; however, small-molecule drugs such as corticosteroids do not provide prolonged relief. One possible reason for their lack of efficacy is high clearance rates from the joint through constant lymphatic drainage of the synovial tissues and synovial fluid and also by their exchange via the synovial vasculature. Advanced drug delivery strategies for extended release of therapeutic agents in the joint space is a promising approach to improve outcomes for OA patients. Broadly, the basic principle behind this strategy is to encapsulate therapeutic agents in a polymeric drug delivery system (DDS) for diffusion- and/or degradation-controlled release, whereby degradation can occur by hydrolysis or tied to relevant microenvironmental cues such as pH, reactive oxygen species (ROS), and protease activity. In this review, we highlight the development of clinically tested IA therapies for OA and highlight recent systems which have been investigated preclinically. DDS strategies including hydrogels, liposomes, polymeric microparticles (MPs) and nanoparticles (NPs), drug conjugates, and combination systems are introduced and evaluated for clinical translational potential.

MicroRNA-17-5p Reduces Inflammation and Bone Erosions in Mice With Collagen-Induced Arthritis and Directly Targets the JAK/STAT Pathway in Rheumatoid Arthritis Fibroblast-like Synoviocytes

OBJECTIVE

We undertook this study to examine microRNA (miRNA) expression across rheumatoid arthritis (RA) phenotypes, along with the effects and mechanisms of action of miRNA-17-5p (miR-17).

METHODS

A miRNA array was performed in synovial tissue biopsied from patients with naive erosive RA (n = 3) and patients with nonerosive RA (n = 3). MicroRNA-17 lipoplex was delivered intraarticularly in the murine collagen-induced arthritis model. Clinical, histologic, and structural effects were studied over the course of arthritis. In-depth studies of the mechanisms of action of miR-17 were performed in primary RA fibroblast-like synoviocytes (FLS) isolated from synovial tissue.

RESULTS

Fifty-five miRNAs including miR-17 were reduced in erosive RA. The miR-17 transfection into arthritic paws reduced the clinical inflammation score between day 2 and day 7 (2.8 versus 1.9; P = 0.03). Synovial B cell, T cell, macrophage, and polynuclear neutrophil infiltration was significantly reduced. Structural damage was also decreased, as shown by a reduction in the number of osteoclasts detected using tartrate-resistant acid phosphatase staining (osteoclast surface/bone surface 32% versus 18%; P = 0.005) and erosion score by computed tomography analysis (2.9 versus 1.7; P = 0.023). Proinflammatory cytokines from the interleukin-6 (IL-6) family and IL-1β expression were also significantly reduced, but tumor necrosis factor was not. MicroRNA-17 directly targeted the 3'-untranslated regions of STAT3 and JAK1. STAT3 and JAK1 messenger RNA (mRNA) and protein expression were reduced in RA FLS following miR-17 transfection. STAT3 and JAK1 mRNA and activation of STAT3, as assessed by immunohistochemistry, were also reduced in injected paws (% stained area 93% versus 62%; P = 0.035).

CONCLUSION

We demonstrate an antiinflammatory and antierosive role of miR-17 in vivo. This effect involves the suppression of the IL-6 family autocrine-amplifying loop through the direct targeting of JAK1 and STAT3.

Serum uromodulin is inversely associated with biomarkers of subclinical inflammation in the population-based KORA F4 study

Background

Uromodulin is a kidney-specific glycoprotein synthesized in tubular cells of Henle’s loop exerting nephroprotective and immunomodulatory functions in the urinary tract. A small amount of uromodulin is also released into the systemic circulation, where its physiological role is unknown. Serum uromodulin (sUmod) has been associated with metabolic risk factors and with cardiovascular events and mortality, where these associations were partly stronger in men than in women. In this study, we investigated the associations of sUmod with biomarkers of subclinical inflammation in a population-based sample of women and men.

Methods

Associations of sUmod with 10 biomarkers of subclinical inflammation were assessed in 1065 participants of the Cooperative Health Research in the Region of Augsburg (KORA) F4 study aged 62–81 years using linear regression models adjusted for sex, age, body mass index, estimated glomerular filtration rate and diabetes. Analyses were performed in the total study sample and stratified by sex.

Results

sUmod was inversely associated with white blood cell count, high-sensitive C-reactive protein, interleukin (IL)-6, tumour necrosis factor-α, myeloperoxidase, superoxide dismutase-3, IL-1 receptor antagonist and IL-22 after multivariable adjustment and correction for multiple testing (P < 0.001 for each observation). There was a trend towards a stronger association of sUmod with pro-inflammatory markers in men than in women, with a significant P for sex interaction (<0.001) regarding the relation of sUmod with IL-6.

Conclusions

sUmod was inversely associated with biomarkers of subclinical inflammation in older participants of the KORA F4 study. The association of sUmod with IL-6 differed between women and men. Future research should focus on whether the immunomodulatory properties of sUmod are one explanation for the association of sUmod with cardiovascular outcomes and mortality.

Regucalcin enhances adipocyte differentiation and attenuates inflammation in 3T3-L1 cells

Dysregulation of adipocyte differentiation and dysfunction play key roles in the pathogenesis of obesity and associated disorders such as diabetes and metabolic syndrome, and as such, a better understanding of the molecular mechanism of adipogenesis may help to elucidate the pathological condition of obesity and its associated disorders. Regucalcin (RGN) plays multiple regulatory roles in intracellular Ca²⁺ signaling pathways in mammalian cells. Here, we report that overexpression of RGN enhances lipid accumulation in 3T3‐L1 adipocyte cells after adipogenic stimulation, accompanied by upregulation of adipocyte differentiation marker proteins. In contrast, genetic disruption of RGN inhibited adipogenic stimulation‐induced differentiation of 3T3‐L1 cells. Furthermore, RGN overexpression in differentiated 3T3‐L1 adipocytes blocked inflammatory crosstalk between 3T3‐L1 adipocytes and RAW264.7 macrophages in a transwell coculture system. Knockdown of RGN expression in cocultured 3T3‐L1 adipocytes enhanced their susceptibility to RAW264.7 macrophage‐mediated inflammation. These results suggest that RGN is required for 3T3‐L1 adipocyte differentiation and that it exerts anti‐inflammatory activity against 3T3‐L1 adipocyte inflammation after coculture with RAW264.7 macrophages. Thus, RGN may be a novel regulator of adipocyte differentiation and act as a suppressor of inflammation in macrophage‐infiltrated adipocyte tissue.

Javamide-II Inhibits IL-6 without Significant Impact on TNF-alpha and IL-1beta in Macrophage-Like Cells

The main aim of this study is to find a therapeutic compound to inhibit IL-6, not TNF-alpha and IL-1beta, in macrophage-like cells, because the high-levels of IL-6 production by macrophages are reported to cause unfavorable outcomes under several disease conditions (e.g., autoimmune diseases, and acute viral infections, including COVID-19). In this study, the potential effects of javamide-II on IL-6, IL-1beta and TNF-alpha productions were determined using their ELISA kits in macrophage-like THP-1 cells. Western blots were also performed using the same cells, to determine its effects on signaling pathways (ERK, p38, JNK, c-Fos, ATF-2, c-Jun and NF-κB p65). At concentrations of 0.2–40 µM, javamide-II inhibited IL-6 production significantly in the THP-1 cells (IC₅₀ of 0.8 µM) (P < 0.02). However, javamide-II did not inhibit IL-1beta or TNF-alpha productions much at the same concentrations. In addition, the treatment of javamide-II decreased the phosphorylation of p38 without significant effects on ERK and JNK phosphorylations in the THP-1 cells. Furthermore, the p38 inhibition, followed by the reduction of ATF-2 phosphorylation (not c-Fos, c-Jun or NF-κB p65), led to the suppression of IL-6 mRNA expression in the cells (P < 0.02). The data indicate that javamide-II may be a potent compound to inhibit IL-6 production via suppressing the p38 signal pathway, without significant effects on the productions of TNF-alpha and IL-1beta in macrophage-like THP-1 cells.

Molecular mechanisms underlying rheumatoid arthritis and cancer development and treatment

Given recent advances in cancer immune therapy, specifically use of checkpoint inhibitors, understanding the link between autoimmunity and cancer is essential. Rheumatoid arthritis (RA) affects about 1% of the population, and early diagnosis is key to prevent joint damage. Management consists of disease-modifying antirheumatic drugs that alter normal immunologic pathways, which could affect malignancy growth and survival. Prolonged immune dysregulation and the resulting inflammatory response associated with development of RA may also lead to increased cancer development risk. RA has long been associated with increased risk of non-Hodgkin's lymphoma [1] and further evidence supports relationship to lung cancer [2]. This review will address the mechanisms behind cancer development and progression in RA patients, biomarkers and assess cancer risk and early detection.

Study on the Multitarget Mechanism and Key Active Ingredients of Herba Siegesbeckiae and Volatile Oil against Rheumatoid Arthritis Based on Network Pharmacology

BACKGROUND

Herba Siegesbeckiae (HS, Xixiancao in Chinese) is widely used to treat inflammatory joint diseases such as rheumatoid arthritis (RA) and arthritis, and its molecular mechanisms and active ingredients have not been completely elucidated.

METHODS

In this study, the small molecule ligand library of HS was built based on Traditional Chinese Medicine Systems Pharmacology (TCMSP). The essential oil from HS was extracted through hydrodistillation and analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). The target of RA was screened based on Comparative Toxicogenomics Database (CTD). The key genes were output by the four algorithms' maximum neighborhood component (MNC), degree, maximal clique centrality (MCC), and stress in cytoHubba in Cytoscape, while biological functions and pathways were also analyzed. The key active ingredients and mechanism of HS and essential oil against RA were verified by molecular docking technology (Sybyl 2.1.1) in treating RA. The interaction between 6 active ingredients (degree ≥ 5) and CSF2, IL1β, TNF, and IL6 was researched based on the software Ligplot.

RESULTS

There were 31 small molecule constituents of HS and 16 main chemical components of essential oil (relative content >1%) of HS. There were 47 chemical components in HS. Networks showed that 9 core targets (TNF, IL1β, CSF2, IFNG, CTLA4, IL18, CD26, CXCL8, and IL6) of RA were based on Venn diagrams. In addition, molecular docking simulation indicated that CSF2, IL1β, TNF, and IL6 had good binding activity with the corresponding compounds (degree > 10).The 6 compounds (degree ≥ 5) of HS and essential oil had good interaction with 5 or more targets.

CONCLUSION

This study validated and predicted the mechanism and key active ingredients of HS and volatile oil in treating RA. Additionally, this study provided a good foundation for further experimental studies.

Discovery of a potent p38α/MAPK14 kinase inhibitor: Synthesis, in vitro/in vivo biological evaluation, and docking studies

This article reports the synthesis of new triarylpyrazole derivatives possessing urea or amide linker, and their biological activities at molecular, cellular, and in vivo levels. Compound 2b was the most potent inhibitor of p38α/MAPK14 kinase (IC₅₀ = 22 nM) among this series. Molecular docking studies were conducted to understand the kinase inhibitory variations and the basis of selectivity. Compound 2b was able to inhibit p38α/MAPK14 kinase inside HEK293 cells in nanoBRET cellular kinase assay with EC₅₀ value of 0.55 μM, comparable to the potency of dasatinib. Compound 2b inhibited TNF-α production in lipopolysaccharide-induced THP-1 cells with IC₅₀ value of 58 nM. In addition, compound 2b showed low potency against hERG. It is 622.38 times less potent than E-4031 against hERG, so the risk of cardiotoxicity of the compound is very minimal. Compound 2b showed also high plasma stability in vitro in human and rat plasmas. The in vivo PK profile of compound 2b is acceptable, and its antiinflammatory effect was comparable to diclofenac with no ulcerogenic side effect on stomach.

Effects of eicosapentaenoic acid and docosahexaenoic acid on C2C12 cell adipogenesis and inhibition of myotube formation

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) modulate cellular metabolic functions and gene expression. This study investigated the impacts of EPA and DHA on gene expression and morphological changes during adipogenic inducement in C2C12 myoblasts. Cells were cultured and treated with differentiation medium with and without 50 μM EPA and DHA. Cells treated with fatty acids had noticeable lipid droplets, but no formation of myotubes compared to control group cells. The expression levels of key genes relevant to adipogenesis and inflammation were significantly higher (P < 0.05) in cells treated with fatty acids. Genes associated with myogenesis and mitochondrial biosynthesis and function had lower (P < 0.05) expression with fatty acids supplementation. Moreover, fatty acid treatment reduced (P < 0.05) oxygen consumption rate in the differentiated cells. This suggested blocking myotube formation through supplementation with EPA and DHA drove myoblasts to enter the quiescent state and enabled adipogenic trans-differentiation of the myoblasts. Data also suggested that overdosage of EPA and DHA during gestation may drive fetal mesenchymal stem cell differentiation to the fate of adipogenesis and have a long-term effect on childhood obesity.

Mitochondrial DNA plays an important role in lung injury induced by sepsis

The effects and mechanisms of mitochondrial DNA (mtDNA) in the development of sepsis-induced lung injury is not well understood. In our present study, we studied the mtDNA effects in sepsis-induced lung injury model, in vitro and in vivo. Compared with the Normal group, the lung histopathological score, the number of positive apoptosis cell, wet/dry (W/D) ratio and TNF-α, IL-1β, and IL-6 concentrations of lipopolysaccharides (LPSs) and mtDNA groups were significantly increased (P < 0.001, respectively). Meanwhile, the lung histopathological score, positive W/D ratio, number of apoptosis cell and tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 concentrations of LPS + mtDNA and small interfering RNA (siRNA)-NC + LPS + mtDNA groups were significantly upregulated compared with those of LPS group (P < 0.05, respectively). However, the lung histopathological score, the number of positive apoptosis cell, W/D ratio and TNF-α, IL-1β, and IL-6 concentrations were significantly improved within the toll-like receptor (TLR9)siRNA + LPS + mtDNA group compared with the LPS group (P < 0.01, respectively). The TLR9, MyD88, and NF-κB proteins or gene expressions of the LPS group and mtDNA group were significantly upregulated compared with those of Normal group by Western blot analysis or immunohistochemistry assay (P < 0.01, respectively), and the TLR9, MyD88, and NF-κB proteins or gene expressions of LPS + mtDNA and siRNA-NC + LPS + mtDNA groups were significantly enhanced compared with those of LPS group (P < 0.05, respectively). However, the TLR9, MyD88, and NF-κB proteins or gene expressions of TLR9siRNA + LPS + mtDNA group were significantly suppressed compared with those of the LPS group (P < 0.01, respectively). In conclusion, mtDNA could provoke lung injury induced by sepsis via regulation of TLR9/MyD88/NF-κB pathway in vitro and in vivo.

Association of polymorphisms at -174 in IL-6, and -308 and -238 in TNF-α, in the development of tuberculosis and type 2 diabetes mellitus in the Mexican population

Polymorphisms at -176 in IL-6, and -238 and -308 in TNF-α have been described as risk factors for developing tuberculosis (TB) and type 2 diabetes mellitus (T2DM). However, it is not known how these changes influence the development of TB-T2DM comorbidity. The objective of this work was therefore to analyze the impact of these polymorphisms in the Mexican population. This is a cross-sectional study of cases and controls in which polymorphisms at -174 in IL-6, -238 and -308 in TNF-α were identified in healthy subjects, those with TB, T2DM and carriers of the comorbidity, each group consisted of 30 individuals. Descriptions of the population, frequency of genotypes and risk association were calculated, and a reduction of multifactorial dimensionality between groups (MDR) was determined. Genotype 174 G/G-of IL-6 was observed in 78% of individuals, while -308 G/G and -238 G/G of TNF-α occurred in 90% and 91% of individuals, respectively. The -174 G/G IL-6 in individuals with T2DM increased five-fold (p = .02) the risk of developing the comorbidity. The MDR analysis showed that the association of -174 G/G IL-6 and -308 G/G TNF-α in healthy individuals increased the risk of developing the comorbidity up to six-fold (p = .019), while in individuals with T2DM, this risk augmented 14-fold (p = .0002). The -174 G/G IL-6 genotype increases the risk of developing comorbidity in the T2DM population and this risk is raised when associated with -308 G/G TNF-α. These findings have implications for understanding the epidemiological dynamics of the TB-T2DM comorbidity, promoting prevention strategies and inhibiting the development of this co-morbidity.

Loss of DBC1 (CCAR2) affects TNFα-induced lipolysis and Glut4 gene expression in murine adipocytes

STAT5A (signal transducer and activator of transcription 5A) is a transcription factor that plays a role in adipocyte development and function. In this study, we report DBC1 (deleted in breast cancer 1; also known as CCAR2) as a novel STAT5A-interacting protein. DBC1 has been primarily studied in tumor cells, but there is evidence that loss of this protein may promote metabolic health in mice. Currently, the functions of DBC1 in mature adipocytes are largely unknown. Using immunoprecipitation and immunoblotting techniques, we confirmed that there is an association between endogenous STAT5A and DBC1 proteins under physiological conditions in the adipocyte nucleus that is not dependent upon STAT5A tyrosine phosphorylation. We used siRNA to knockdown DBC1 in 3T3-L1 adipocytes to determine the impact on STAT5A activity, adipocyte gene expression, and TNFα (tumor necrosis factor α)-regulated lipolysis. The loss of DBC1 did not affect the expression of several STAT5A target genes including Socs3, Cish, Bcl6, Socs2, and Igf1 However, we did observe decreased levels of TNFα-induced glycerol and free fatty acids released from adipocytes with reduced DBC1 expression. In addition, DBC1-knockdown adipocytes had increased Glut4 expression. In summary, DBC1 can associate with STAT5A in adipocyte nucleus, but it does not appear to impact regulation of STAT5A target genes. Loss of adipocyte DBC1 modestly increases Glut4 gene expression and reduces TNFα-induced lipolysis. These observations are consistent with in vivo observations that show loss of DBC1 promotes metabolic health in mice.

Intrinsic anti-inflammatory properties in the serum of two species of deep-diving seal

Weddell and elephant seals are deep-diving mammals, which rely on lung collapse to limit nitrogen absorption and prevent decompression injury. Repeated collapse and re-expansion exposes the lungs to multiple stressors, including ischemia-reperfusion, alveolar shear stress and inflammation. There is no evidence, however, that diving damages pulmonary function in these species. To investigate potential protective strategies in deep-diving seals, we examined the inflammatory response of seal whole blood exposed to lipopolysaccharide (LPS), a potent endotoxin. Interleukin-6 (IL6) cytokine production elicited by LPS exposure was 50 to 500 times lower in blood of healthy northern elephant seals and Weddell seals compared with that of healthy human blood. In contrast to the ∼6× increased production of IL6 protein from LPS-exposed Weddell seal whole blood, isolated Weddell seal peripheral blood mononuclear cells, under standard cell culture conditions using medium supplemented with fetal bovine serum (FBS), produced a robust LPS response (∼300×). Induction of Il6 mRNA expression as well as production of IL6, IL8, IL10, KC-like and TNFα were reduced by substituting FBS with an equivalent amount of autologous seal serum. Weddell seal serum also attenuated the inflammatory response of RAW 267.4 mouse macrophage cells exposed to LPS. Cortisol level and the addition of serum lipids did not impact the cytokine response in cultured cells. These data suggest that seal serum possesses anti-inflammatory properties, which may protect deep divers from naturally occurring inflammatory challenges such as dive-induced hypoxia-reoxygenation and lung collapse.

Interleukin-6: A promising cytokine to support liver regeneration and adaptive immunity in liver pathologies

Liver pathologies (fibrosis, cirrhosis, alcoholic, non-alcoholic diseases and hepatocellular carcinoma) represent one of the most common causes of death worldwide. A number of genetic and environmental factors contribute to the development of liver diseases. Interleukin-6 (IL-6) is a pleiotropic cytokine, exerting variety of effects on inflammation, liver regeneration, and defence against infections by regulating adaptive immunity. Due to its high abundance in inflammatory settings, IL-6 is often viewed as a detrimental cytokine. However, accumulating evidence supports the view that IL-6 has a beneficial impact in numerous liver pathologies, due to its roles in liver regeneration and in promoting an anti-inflammatory response in certain conditions. IL-6 promotes proliferation, angiogenesis and metabolism, and downregulates apoptosis and oxidative stress; together these functions are critical for mediating hepatoprotection. IL-6 is also an important regulator of adaptive immunity where it induces T cell differentiation and regulates autoimmunity. It can augment antiviral adaptive immune responses and mitigate exhaustion of T cells during chronic infection. This review focuses on studies that present IL-6 as a key factor in regulating liver regeneration and in supporting effector immune functions and suggests that these functions of IL-6 can be exploited in treatment strategies for liver pathologies.

TNF stimulates IL-6, CXCL8 and VEGF secretion from human keratinocytes via activation of mTOR, inhibited by tetramethoxyluteolin

Psoriasis is an autoimmune skin disease characterized by keratinocyte hyperproliferation and chronic inflammation. The pathogenesis of psoriasis involves proinflammatory cytokines, such as tumor necrosis factor (TNF), but the mechanism of keratinocyte activation is not well understood. Here, we show that TNF (10 or 50 ng/mL) stimulates a significant (P < .0001) gene expression and secretion of proinflammatory IL-6, CXCL8 and VEGF from both cultured human HaCaT and normal epidermal human keratinocytes (NHEKs). This effect occurs via activation of the mammalian target of rapamycin (mTOR) signalling complex as shown by Western blot analysis and phospho-ELISAs. Pretreatment with the novel natural flavonoid tetramethoxyluteolin (10-100 μmol L^-1 ) significantly (P < .0001) inhibits gene expression and secretion (P < .0001) of all 3 mediators in a concentration-dependent manner. Moreover, tetramethoxyluteolin (50 μmol L^-1 ) appears to be a potent inhibitor of the phosphorylated mTOR substrates (pmTOR^Ser2448 , pp70S6K^Thr389 and p4EBP1^Thr37/46 ) as compared to known mTOR inhibitors in keratinocytes. The present findings indicate that TNF stimulates skin inflammation via mTOR signalling. Inhibition by tetramethoxyluteolin may be used in the treatment for psoriasis.

EMMPRIN Inhibits bFGF-Induced IL-6 Secretion in an Osteoblastic Cell Line, MC3T3-E1

Background: Electrolytically-generated acid functional water (FW) is obtained by electrolyzing low concentrations of saline. Although it has been widely used in clinical practice with various purposes, the underlying mechanisms of action involved have not been fully elucidated so far. We used the human cervical cancer-derived fibroblastic cell line (HeLa), to examine the cytokine secretion profile following FW treatment in the present study. Results: FW stimulation significantly induced the secretion of basic fibroblast growth factor (bFGF) and extracellular matrix metalloproteinase inducer (EMMPRIN). The effect of both factors on osteoblast-like MC3T3-E1 cells was further examined by stimulating the cells with the conditioned medium of FW-stimulated HeLa cells. However, the conditioned medium failed to induce IL-6 secretion. The MC3T3-E1 cells were further stimulated with recombinant bFGF or EMMPRIN or a combination of both factors. Intriguingly, bFGF-stimulated IL-6 induction was totally inhibited by EMMPRIN. Pretreatment with the specific inhibitor of nuclear factor-kappa B (NF-κB) drastically inhibited IL-6 secretion indicating that bFGF-induced IL-6 expression was dependent on NF-κB activation. The phosphorylation status of NF-κB p65 subunit was further examined. The results indicated that EMMPRIN inhibited bFGF-induced NF-κB p65 phosphorylation. Conclusions: These findings suggest that bFGF can induce IL-6 secretion in MC3T3-E1 cells through NF-κB activation. As EMMPRIN inhibited bFGF-induced IL-6 secretion by reducing the p65 subunit phosphorylation, it might be concluded that bFGF and EMMPRIN crosstalk in their respective signaling pathways.

Ghrelin Inhibits Interleukin-6 Production Induced by Cigarette Smoke Extract in the Bronchial Epithelial Cell Via NF-κB Pathway

Cigarette smoke (CS)-induced airway inflammation is the main pathogenesis of COPD. The present study was designed to evaluate whether ghrelin, a novel growth hormone-releasing peptide, can affect the pro-inflammatory cytokine interleukin-6 (IL-6) production induced by cigarette smoke extract (CSE) in the human bronchial epithelial cell line (16-HBE) and its possible mechanism. 16-HBE cells were pre-incubated with vehicle or ghrelin (0.1 to 1000 ng/mL) in a concentration-dependent manner, and then CSE (0 to 16 %) was added. The protein levels of IL-6 in the medium were determined by ELISA, and the mRNA expressions of IL-6 was detected by RT-PCR. We also detected the phosphorylation of IKKα/β/p65 protein and the degradation of inhibitory protein-κB (I-κB) by Western blot analysis. And the generation of reactive oxygen species (ROS) in 16-HBE was evaluated by labeling specific fluorescence probes DCFH-DA. 16-HBE Cells treated with CSE (8 %) exhibited significantly higher IL-6 production compared with cells treated with vehicle alone (P < 0.05). Ghrelin suppressed CSE-induced IL-6 production at both mRNA and protein levels in a concentration-dependent manner (P < 0.05). Moreover, ghrelin attenuated CSE-triggered NF-κB activation in 16-HBE, but the intracellular ROS level after application of CSE was not affected by ghrelin (0.1 to 1000 ng/mL). Together, these results suggest that ghrelin inhibits CSE-induced IL-6 production in 16-HBE cells by targeting on NF-κB pathway, but not by scavenging intracellular ROS.

Transplantation of Adipose-Derived Stem Cell Sheet Attenuates Adverse Cardiac Remodeling in Acute Myocardial Infarction

Adipose-derived stem cell (ADSC) transplantation has been proposed to improve cardiac function and acute myocardial infarction (AMI). Recently, cell sheet technology has been investigated for its potential applicability in cardiac injury. However, a detailed comparison of the functional recovery in the injured myocardium between cell sheets and conventional cell injection has not been adequately examined. ADSCs were isolated from the inguinal fat tissue of ICR mice. Three groups of AMI induction only (sham), intramyocardial injection of ADSCs (imADSC), and ADSC sheet transplantation (shADSC) were compared by using rat AMI models. Engraftment of ADSCs was better sustained through 28 days in the shADSC group compared with the imADSC group. Ejection fraction was improved in both imADSC and shADSC groups compared with the sham group. Ventricular wall thickness in the infarct zone was higher in the shADSC group compared with both imADSC and sham groups. Growth factor and cytokine expression in the implanted heart tissue were higher in the shADSC group compared with both imADSC and sham groups. Furthermore, only the shADSC group showed donor-derived vessels at the peri-infarct zone. Taken together, these results indicate that, although shADSC resulted in a similar improvement in left ventricular systolic function, it significantly promoted cellular engraftment and upregulated growth factor and cytokine expression, and, ultimately, attenuated adverse cardiac remodeling in rat AMI models compared with imADSC.

An asthma-associated IL4R variant exacerbates airway inflammation by promoting conversion of regulatory T cells to TH17-like cells

Mechanisms by which regulatory T (Treg) cells fail to control inflammation in asthma remain poorly understood. We show that a severe asthma-associated polymorphism in the gene encoding the interleukin (IL)-4 receptor alpha chain (Il4ra(R576)) promotes conversion of induced Treg (iTreg) cells toward a T helper 17 (TH17) cell fate. This skewing is mediated by the recruitment by IL-4Rα(R576) of the growth-factor-receptor-bound protein 2 (GRB2) adaptor protein, which drives IL-17 expression by activating a pathway that involves extracellular-signal-regulated kinase, IL-6 and the transcription factor STAT3. Treg cell-specific deletion of genes that regulate TH17 cell differentiation, including Il6ra and RAR-related orphan receptor gamma (Rorc), but not of Il4 or Il13, prevented exacerbated airway inflammation in mice expressing Il4ra(R576) (hereafter referred to as Il4ra(R576) mice). Furthermore, treatment of Il4ra(R576) mice with a neutralizing IL-6-specific antibody prevented iTreg cell reprogramming into TH17-like cells and protected against severe airway inflammation. These findings identify a previously unknown mechanism for the development of mixed TH2-TH17 cell inflammation in genetically prone individuals and point to interventions that stabilize iTreg cells as potentially effective therapeutic strategies.

MiR-26 down-regulates TNF-α/NF-κB signalling and IL-6 expression by silencing HMGA1 and MALT1

MiR-26 has emerged as a key tumour suppressor in various cancers. Accumulating evidence supports that miR-26 regulates inflammation and tumourigenicity largely through down-regulating IL-6 production, but the underlying mechanism remains obscure. Here, combining a transcriptome-wide approach with manipulation of cellular miR-26 levels, we showed that instead of directly targeting IL-6 mRNA for gene silencing, miR-26 diminishes IL-6 transcription activated by TNF-α through silencing NF-κB signalling related factors HMGA1 and MALT1. We demonstrated that miR-26 extensively dampens the induction of many inflammation-related cytokine, chemokine and tissue-remodelling genes that are activated via NF-κB signalling pathway. Knocking down both HMGA1 and MALT1 by RNAi had a silencing effect on NF-κB-responsive genes similar to that caused by miR-26. Moreover, we discovered that poor patient prognosis in human lung adenocarcinoma is associated with low miR-26 and high HMGA1 or MALT1 levels and not with levels of any of them individually. These new findings not only unravel a novel mechanism by which miR-26 dampens IL-6 production transcriptionally but also demonstrate a direct role of miR-26 in down-regulating NF-κB signalling pathway, thereby revealing a more critical and broader role of miR-26 in inflammation and cancer than previously realized.

Cannabidiol protects an in vitro model of the blood-brain barrier from oxygen-glucose deprivation via PPARγ and 5-HT1A receptors

BACKGROUND AND PURPOSE

In vivo and in vitro studies have demonstrated a protective effect of cannabidiol (CBD) in reducing infarct size in stroke models and against epithelial barrier damage in numerous disease models. We aimed to investigate whether CBD also affects blood-brain barrier (BBB) permeability following ischaemia.

EXPERIMENTAL APPROACH

Human brain microvascular endothelial cell (HBMEC) and human astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance.

KEY RESULTS

CBD (10 μM) prevented the increase in permeability caused by 4 h OGD. CBD was most effective when administered before the OGD, but protective effects were observed up to 2 h into reperfusion. This protective effect was inhibited by a PPARγ antagonist and partly reduced by a 5-HT1A receptor antagonist, but was unaffected by antagonists of cannabinoid CB1 or CB2 receptors, TRPV1 channels or adenosine A2A receptors. CBD also reduced cell damage, as measured by LDH release and by markers of cellular adhesion, such as the adhesion molecule VCAM-1. In HBMEC monocultures, CBD decreased VCAM-1 and increased VEGF levels, effects which were inhibited by PPARγ antagonism.

CONCLUSIONS AND IMPLICATIONS

These data suggest that preventing permeability changes at the BBB could represent an as yet unrecognized mechanism of CBD-induced neuroprotection in ischaemic stroke, a mechanism mediated by activation of PPARγ and 5-HT1A receptors.

Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte

The innate immune response is characterized by activation of transcription factors, nuclear factor kappa B and activator protein-1 and their downstream targets, the pro-inflammatory cytokines including interleukin 1β and interleukin 6. Normal development of this response in the intestine is critical to survival of the human neonate and delays can cause the onset of devastating inflammatory diseases such as necrotizing enterocolitis. Previous studies have addressed the role of nuclear factor kappa B in the development of the innate immune response in the enterocyte, however despite its central role in the control of multiple pro-inflammatory cytokine genes, little is known on the role of Activator Protein 1 in this response in the enterocyte. Here we show that the canonical Activator Protein 1 members, cJun and cFos and their upstream kinases JNK and p38 play an essential role in the regulation of interleukin 6 in the immature enterocyte. Our data supports a model whereby the cFos/cJun heterodimer and the more potent cJun homodimer downstream of JNK are replaced by less efficient JunD containing dimers, contributing to the decreased responsiveness to interleukin 1β and decreased interleukin 6 secretion observed in the mature enterocyte. The tissue specific expression of JunB in colonocytes and colon derived tissues together with its ability to repress Interleukin-1β induction of an Interleukin-6 gene reporter in the NCM-460 colonocyte suggests that induction of JunB containing dimers may offer an attractive therapeutic strategy for the control of IL-6 secretion during inflammatory episodes in this area of the intestine

Regulation of IL-6 in Immunity and Diseases

Interleukin-6 (IL-6) is a prototypical cytokine with functional pleiotropy and plays an important role in host defense. When infections or tissue injuries occur, IL-6 is promptly produced by monocytes and macrophages and contributes to removal of infectious agents and restoration of damaged tissues through activation of immune, hematological, and acute-phase responses. Once stress is removed from the host, IL-6 synthesis ends, but uncontrolled excessive or persistent IL-6 production plays a pathological role in the development of various inflammatory diseases and cancers, indicating that IL-6 is a double-edged sword for the host. Thus, the proper IL-6 expression is very important for host defense and is strictly controlled by chromatin structure, transcriptional regulation, and posttranscriptional modification. Differentiation status of cells, various transcription factors, RNA-binding proteins, and microRNAs are involved in this process. Since it is assumed that dysregulation of any of these regulatory molecules may cause abnormal IL-6 expression in a particular disease, further elucidation of the factors and processes involved in IL-6 expression can be expected to facilitate to clarification of pathogenesis and to identification of novel target molecule(s) for specific diseases.

Genetic polymorphism directs IL-6 expression in fibroblasts but not selected other cell types

Interleukin (IL)-6 blockade is an effective treatment for rheumatoid arthritis (RA), and synovial fibroblasts are a major IL-6 producer in the inflamed joint. We found that human RA and osteoarthritis (OA) synovial fibroblasts derived from independent donors reproducibly segregated into low, medium, and high IL-6 producers, independent of stimulus, cell passage, or disease state. IL-6 expression pattern correlated strongly with total mRNA expression, not mRNA stability, suggesting transcriptional rather than posttranscriptional regulation. High-fibroblast IL-6 expression was significantly associated with the IL-6 proximal promoter single nucleotide polymorphism (SNP) rs1800795 minor allele (CC) genotype. In contrast, no association between this SNP and IL-6 production was detected in CD14(+) monocytes, another major producer of synovial IL-6. Luciferase expression assays confirmed that this SNP was associated with differential IL-6 expression in fibroblasts. To date, several association studies examining rs1800795 allele frequency and disease risk have reported seemingly conflicting results ranging from no association to association with either the major or minor allele across a spectrum of conditions, including cancer and autoimmune, cardiovascular, infectious, and metabolic diseases. This study points to a prominent contribution from promoter genetic variation in fibroblast IL-6 regulation, but not in other IL-6-producing cell types. We propose that some of the heterogeneity in these clinical studies likely reflects the cellular source of IL-6 in specific diseases, much of which may be produced by nonhematopoietic cells. These results highlight that functional analysis of disease-associated SNPs on gene expression and pathologic processes must consider variation in diverse cell types.

Influence of Promoter Polymorphisms of the TNF-α (-308G/A) and IL-6 (-174G/C) Genes on Therapeutic Response to Etanercept in Rheumatoid Arthritis

Background

The study was undertaken to assess the influence of functional -308G/A TNF-α (rs 1800629) and -174G/C IL-6 (rs1800795) promoter polymorphisms on the therapeutic response to etanercept, a TNF-α blocker, in patients with rheumatoid arthritis (RA).

Methods

Seventy-three patients suffering from active RA were studied, at baseline and 6 and 12 months after therapy. The therapeutic response was estimated according to the European League Against Rheumatism response criteria. Patients were genotyped for -308G/A TNF-α and -174G/C IL-6 polymorphisms by the PCR-RFLP method, and the influence of genotype on etanercept response was assessed.

Results

No difference in the percentage of responders (patients who had DAS28 improvement > 1.2) between patients with the TNF-α-308GG and GA and AA genotype was detected after 6 and 12 months of treatment. After 12 months of treatment the percentage of responders was significantly increased in patients with the IL-6 -174GG genotype compared with those with the GC or CC genotype (p=0.006 by Chi-square test). Evaluation of the patients according to their combined IL-6/TNF-α genotypes showed that patients with the IL-6 -174GG / TNF-α-308GG genotype were more frequent among the responders compared to those with other combined genotypes (p=0.022 by Chi-square test). More precisely, all patients with the combined IL-6 -174GG / TNF-α-308GG genotype were responders after 12 months of etanercept treatment.

Conclusions

The study suggests that patients who are genetically low TNF-α and IL-6 producers are the best responders to etanercept therapy.

Bilberry-derived anthocyanins prevent IFN-γ-induced pro-inflammatory signalling and cytokine secretion in human THP-1 monocytic cells

BACKGROUND/AIMS

Anthocyanins are plant-derived dietary components that are highly abundant, for example, in bilberries. We have previously demonstrated that anthocyanins exert anti-inflammatory properties in mouse colitis models and ameliorate disease activity in ulcerative colitis patients. Here, we studied the molecular mechanisms through which anthocyanin-containing bilberry extract (BE) exerts anti-inflammatory effects in human monocytic THP-1 cells.

METHODS

THP-1 cells were pre-incubated with BE 20 min prior to TNF-α or IFN-γ (100 ng/ml each) stimulation. Signalling protein activation was studied by Western blotting, mRNA expression by quantitative PCR and cytokine secretion by ELISA.

RESULTS

IFN-γ-induced phosphorylation of STAT1 and STAT3 was significantly reduced by BE co-treatment. Consequently, levels of mRNA expression and/or cytokine secretion of MCP-1, IL-6, TNF-α, ICAM-1, and T-bet were lower with BE co-treatment. In contrast, BE enhanced TNF-α-mediated p65-NF-κB phosphorylation but reduced ERK1/2 phosphorylation. BE co-treatment further increased TNF-α-induced mRNA expression and secretion of NF-κB target genes, such as IL-6, IL-8, and MCP-1, while mRNA levels of ICAM-1 were reduced.

CONCLUSIONS

BE co-treatment reduced IFN-γ-induced signal protein activation, pro-inflammatory gene expression, and cytokine secretion, whereas it enhanced TNF-α-induced responses. These findings suggest a distinct role for anthocyanins in modulating inflammatory responses that need to be further studied to fully understand anthocyanin-mediated effects.

Effect of glycated albumin and cranberry components on interleukin-6 and matrix metalloproteinase-3 production by human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Gingival fibroblasts have the potential to participate in periodontal inflammation and breakdown, producing interleukin (IL)-6 and matrix metalloproteinase (MMP)-3. Advanced glycation end products (AGEs), formed during diabetic hyperglycemia, might aggravate periodontal inflammation. The cranberry contains anti-inflammatory polyphenols, which inhibit proinflammatory activities of lipopolysaccharide (LPS)- and IL-1β-stimulated human cells. Little is known of its effects on gingival fibroblast IL-6 or MMP-3 production stimulated by AGEs. The objectives were to determine cranberry effects on IL-6 and MMP-3 production by gingival fibroblasts exposed to the representative AGE, glycated human serum albumin (G-HSA), or LPS ± G-HSA.

MATERIAL AND METHODS

Cranberry high molecular weight non-dialyzable material (NDM), was derived from cranberry juice. Normal human gingival fibroblasts were incubated with G-HSA or normal HSA or Porphyromonas gingivalis LPS (1 μg/mL) ± G-HSA, in the presence or absence of preincubation with NDM. IL-6 and MMP-3 were measured by enzyme-linked immunosorbent assay. Data were analyzed using one-way analysis of variance and Scheffe's F procedure.

RESULTS

IL-6 production was stimulated by G-HSA or LPS (p < 0.01), which was inhibited in both cases by NDM (p < 0.002). [G-HSA+LPS] synergistically stimulated IL-6 production (p < 0.0001), which was inhibited by NDM. MMP-3 levels were not stimulated by G-HSA but were decreased by LPS (p < 0.02). [G-HSA+LPS] increased MMP-3 production significantly, vs. LPS (p = 0.0005). NDM inhibited MMP-3 levels in the presence of G-HSA or LPS, and in the presence of [G-HSA+LPS] (p < 0.0001).

CONCLUSIONS

G-HSA ± LPS may have differential effects on IL-6 and MMP-3 production by human gingival fibroblasts, but both are inhibited by NDM. The study suggests that cranberry phenols may be useful in regulating the host response and perhaps treating periodontitis in patients with poorly controlled diabetes.

Pharmacological inhibition of caspase-8 limits lung tumour outgrowth

BACKGROUND AND PURPOSE

Lung cancer is one of the leading causes of cancer death worldwide. Despite advances in therapy, conventional therapy is still the main treatment and has a high risk of chemotherapy resistance. Caspase-8 is involved in cell death and is a recognized marker for poor patient prognosis.

EXPERIMENTAL APPROACH

To elucidate the role of caspase-8 in lung carcinoma, we used human samples of non-small cell lung cancer (NSCLC) and a mouse model of carcinogen-induced lung cancer.

KEY RESULTS

Healthy and cancerous NSCLC samples had similar levels of the active form of caspase-8. Similarly, lung tumour-bearing mice had high levels of the active form of caspase-8. Pharmacological inhibition of caspase-8 by z-IETD-FMK robustly reduced tumour outgrowth and this was closely associated with a reduction in the release of pro-inflammatory cytokines, IL-6, TNF-α, IL-18, IL-1α, IL-33, but not IL-1β. Furthermore, inhibition of caspase-8 reduced the recruitment of innate suppressive cells, such as myeloid-derived suppressor cells, but not of regulatory T cells to lungs of tumour-bearing mice. However, despite the well-known role of caspase-8 in cell death, the apoptotic cascade (caspase-3, caspase-9 and Bcl-2 dependent) was not active in lungs of z-IETD-treated tumour-bearing mice, but instead higher levels of the short segment of c-FLIP (c-FLIPs) were detected. Similarly, human healthy lung samples had higher levels of c-FLIPs than cancerous samples.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that caspase-8 is an important orchestrator of cancer-associated inflammation and the presence of short segment of c-FLIP determines whether caspase-8 induces tumour proliferation or tumour arrest/regression in the lung.

Inhibition of IL-6 signaling pathway by curcumin in uterine decidual cells

IL-6 is a multifunctional pro-inflammatory cytokine and has been implicated in many gestational disorders including preterm birth. Currently, there are no appropriate therapeutic interventions available to circumvent inflammatory-mediated gestational disorders. Therefore, the goal of this study was to identify a safe and effective pharmacological compound to counterbalance inflammatory responses in the uterus. Curcumin, a naturally-occuring polyphenolic compound, has been widely used in alternative medicine to treat inflammatory diseases. However, the anti-inflammatory effect of curcumin has not been explored in uterine decidual cells, a major source of IL-6. Therefore, we examined the effect of curcumin on IL-6 expression using two types of uterine decidual cells 1) HuF cells, primary human fibroblast cells obtained from the decidua parietalis; 2) UIII cells, a rodent non-transformed decidual cell line. Curcumin treatment completely abrogated the expression of IL-1β-induced IL-6 in these cells. Curcumin also strongly inhibited the expression of gp130, a critical molecule in IL-6 signaling, whereas expression of IL-6R and sIL-6R was not affected. Curcumin also inhibited phosphorylation and nuclear localization of STAT3, a well-known downstream mediator of IL-6 signaling. Furthermore, curcumin attenuated IL-1β-induced IL-6 promoter reporter activity suggesting transcriptional regulation. To further understand whether NF-ҡB is involved in this inhibition, we examined the effect of curcumin on the expression of p50 and p65 subunits of NF-ҡB in decidual cells. Expression of IL-1β-induced p50 mRNA was repressed by curcumin while p65 mRNA was not affected. However, curcumin treatment dramatically inhibited both p50 and p65 protein levels and prevented its nuclear localization. This effect is at least partly mediated through the deactivation of IKK, since IL-1β-induced IKKα/β phosphorylation is decreased upon curcumin treatment. Our results not only revealed molecular mechanisms underlying curcumin action in uterine decidual cells but also suggest that this compound may have therapeutic potential for the prevention of inflammation-mediated preterm birth and other gestational disorders.

Differential cytokine profiles upon comparing selective versus classic glucocorticoid receptor modulation in human peripheral blood mononuclear cells and inferior turbinate tissue

BACKGROUND

Glucocorticoid Receptor agonists, particularly classic glucocorticoids, are the mainstay among treatment protocols for various chronic inflammatory disorders, including nasal disease. To steer away from steroid-induced side effects, novel GR modulators exhibiting a more favorable therapeutic profile remain actively sought after. Currently, the impact of 2-(4-acetoxyphenyl)-2-chloro-N-methylethylammonium chloride a plant-derived selective glucocorticoid receptor modulator named compound A, on cytokine production in ex vivo human immune cells and tissue has scarcely been evaluated.

METHODS AND RESULTS

The current study aimed to investigate the effect of a classic glucocorticoid versus compound A on cytokine and inflammatory mediator production after stimulation with Staphylococcus aureus-derived enterotoxin B protein in peripheral blood mononuclear cells (PBMCs) as well as in inferior nasal turbinate tissue. To this end, tissue fragments were stimulated with RPMI (negative control) or Staphylococcus aureus-derived enterotoxin B protein for 24 hours, in presence of solvent, or the glucocorticoid methylprednisolone or compound A at various concentrations. Supernatants were measured via multiplex for pro-inflammatory cytokines (IL-1β, TNFα) and T-cell- and subset-related cytokines (IFN-γ, IL-2, IL-5, IL-6, IL-10, and IL-17). In concordance with the previously described stimulatory role of superantigens in the development of nasal polyposis, a 24h Staphylococcus aureus-derived enterotoxin B protein stimulation induced a significant increase of IL-2, IL-1β, TNF-α, and IL-17 in PBMCs and in inferior turbinates and of IL-5 and IFN-γ in PBMCs.

CONCLUSION

Notwithstanding some differences in amplitude, the overall cytokine responses to methylprednisolone and compound A were relatively similar, pointing to a conserved and common mechanism in cytokine transrepression and anti-inflammatory actions of these GR modulators. Furthermore, these results provide evidence that selective glucocorticoid receptor modulator-mediated manipulation of the glucocorticoid receptor in human tissues, supports its anti-inflammatory potential.

Interleukin-6 as a prognostic marker in dogs in an intensive care unit

BACKGROUND

Interleukin-6 (IL-6) is involved in the acute phase reaction during inflammatory disease, including septicemia and the inflammatory response syndrome (SIRS). In people, IL-6 has been studied as a prognostic marker in intensive care medicine, where nonsurvivors had significantly higher IL-6 concentrations than survivors.

OBJECTIVES

The objective of the study was to investigate the prognostic value of IL-6 in dogs admitted to the intensive care unit based on sensitivity and specificity.

METHODS

Dogs suffering from different severe diseases treated in the intensive care unit were divided into 2 groups of survivors and nonsurvivors. Serum IL-6 concentrations were measured with a canine-specific ELISA (enzyme-linked immunosorbent assay) kit.

RESULTS

Sixty-nine dogs were included in the study, including 20 survivors, 9 nonsurvivors, and 40 control dogs. In the control group, IL-6 serum concentrations were below the detection level (0 pg/mL). In the group of nonsurviving dogs, IL-6 ranged from 45-4656 pg/mL (median 1398 pg/mL). The surviving dogs had a range of 0-405 pg/mL (median 84.5 pg/mL). The mean IL-6 concentration was significantly higher (P < .001) in nonsurvivors than in survivors. Using a cutoff of 400 pg/mL, a sensitivity of 90% and specificity of 95% were determined.

CONCLUSIONS

The results of this study suggest that IL-6 is a useful prognostic marker for canine critical care patients with acute internal disease.

Aortic perivascular adipose-derived interleukin-6 contributes to arterial stiffness in low-density lipoprotein receptor deficient mice

We tested the hypothesis that aortic perivascular adipose tissue (PVAT) from young low-density lipoprotein receptor-deficient (LDLr(-/-)) mice promotes aortic stiffness and remodeling, which would be mediated by greater PVAT-derived IL-6 secretion. Arterial stiffness was assessed by aortic pulse wave velocity and with ex vivo intrinsic mechanical properties testing in young (4-6 mo old) wild-type (WT) and LDLr(-/-) chow-fed mice. Compared with WT mice, LDLr(-/-) mice had increased aortic pulse wave velocity (407 ± 18 vs. 353 ± 13 cm/s) and intrinsic mechanical stiffness (5,308 ± 623 vs. 3,355 ± 330 kPa) that was associated with greater aortic protein expression of collagen type I and advanced glycation end products (all P < 0.05 vs. WT mice). Aortic segments from LDLr(-/-) compared with WT mice cultured in the presence of PVAT had greater intrinsic mechanical stiffness (6,092 ± 480 vs. 3,710 ± 316 kPa), and this was reversed in LDLr(-/-) mouse arteries cultured without PVAT (3,473 ± 577 kPa, both P < 0.05). Collagen type I and advanced glycation end products were increased in LDLr(-/-) mouse arteries cultured with PVAT (P < 0.05 vs. WT mouse arteries), which was attenuated when arteries were cultured in the absence of PVAT (P < 0.05). PVAT from LDLr(-/-) mice secreted larger amounts of IL-6 (3.4 ± 0.1 vs. 2.3 ± 0.7 ng/ml, P < 0.05), and IL-6 neutralizing antibody decreased intrinsic mechanical stiffness in LDLr(-/-) aortic segments cultured with PVAT (P < 0.05). Collectively, these data provide evidence for a role of PVAT-derived IL-6 in the pathogenesis of aortic stiffness and remodeling in chow-fed LDLr(-/-) mice.

MicroRNA-22 impairs anti-tumor ability of dendritic cells by targeting p38

Dendritic cells (DCs) play a critical role in triggering anti-tumor immune responses. Their intracellular p38 signaling is of great importance in controlling DC activity. In this study, we identified microRNA-22 (miR-22) as a microRNA inhibiting p38 protein expression by directly binding to the 3' untranslated region (3'UTR) of its mRNA. The p38 down-regulation further interfered with the synthesis of DC-derived IL-6 and the differentiation of DC-driven Th17 cells. Moreover, overexpression of miR-22 in DCs impaired their tumor-suppressing ability while miR-22 inhibitor could reverse this phenomenon and improve the curative effect of DC-based immunotherapy. Thus, our results highlight a suppressive role for miR-22 in the process of DC-invoked anti-tumor immunity and that blocking this microRNA provides a new strategy for generating potent DC vaccines for patients with cancer.

Genetics of serum concentration of IL-6 and TNFα in systemic lupus erythematosus and rheumatoid arthritis: a candidate gene analysis

Elevated concentrations of inflammatory mediators are characteristic of autoimmune disease accompanied by chronic or recurrent inflammation. We examined the hypothesis that mediators of inflammation known to be elevated in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are associated with genetic polymorphism previously identified in studies of inflammatory disease. Serum interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) concentrations in patients with SLE (n = 117) or RA (n = 164) and in inflammatory disease-free control subjects (n = 172) were measured by multiplex ELISA. Candidate genes were chosen from studies of autoimmune and inflammatory disease. Genotypes were determined for 345 SNP markers in 75 genes. Association between serum analytes and single alleles was tested by linear regression. Polymorphisms in several genes were associated with IL-6 levels (including IL10, TYK2, and CD40L in SLE and DRB1, NOD2, and CSF1 in RA) or with TNFα levels (including TNFSF4 and CSF2 in SLE and PTPN2, DRB1, and NOD2 in RA). Some associations were shared between disease and control groups or between IL-6 and TNFα within a group. In conclusion, variation in genes implicated in disease pathology is associated with serum IL-6 or TNFα concentration. Some genetic associations are more apparent in healthy controls than in SLE or RA, suggesting dysregulation of the principal mediators of chronic inflammation in disease. Susceptibility genes may affect inflammatory response with variable effect on disease etiology.

Effect of hydrogen sulfide on inflammatory cytokines in acute myocardial ischemia injury in rats

Hydrogen sulfide (H₂S) is believed to be involved in numerous physiological and pathophysiological processes, and now it is recognized as the third endogenous signaling gasotransmitter, following nitric oxide and carbon monoxide; however, the effects of H₂S on inflammatory factors in acute myocardial ischemia injury in rats have not been clarified. In the present study, sodium hydrosulfide (NaHS) was used as the H₂S donor. Thirty-six male Sprague Dawley rats were randomly divided into five groups: Sham, ischemia, ischemia + low-dose (0.78 mg/kg) NaHS, ischemia + medium-dose (1.56 mg/kg) NaHS, ischemia + high-dose (3.12 mg/kg) NaHS and ischemia + propargylglycine (PPG) (30 mg/kg). The rats in each group were sacrificed 6 h after the surgery for sample collection. Compared with the ischemia group, the cardiac damage in the rats in the ischemia + NaHS groups was significantly reduced, particularly in the high-dose group; in the ischemia + PPG group, the myocardial injury was aggravated compared with that in the ischemia group. Compared with the ischemia group, the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in the serum of rats in the ischemia + medium- and high-dose NaHS groups were significantly reduced, and the expression of intercellular adhesion molecule-1 (ICAM-1) mRNA and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) protein in the myocardial tissues of rats was significantly reduced. In the ischemia + PPG group, the TNF-α, IL-1β and IL-6 levels in the serum were significantly increased, the expression of ICAM-1 mRNA was increased, although without a significant difference, and the expression of NF-κB was increased. The findings of the present study provide novel evidence for the dual effects of H₂S on acute myocardial ischemia injury via the modulation of inflammatory factors.

The effect of ROCK on TNF-α-induced CXCL8 secretion by intestinal epithelial cell lines is mediated through MKK4 and JNK signaling

Intestinal epithelial cells (IEC) play a role in mucosal inflammatory responses by producing important chemokines like CXCL8 when stimulated by TNF-α. Previously, we found that IEC cell lines required the Rho-associated kinase, ROCK, for CXCL8 responses after IL-1 stimulation. This study extends these findings by showing that inhibiting ROCK suppressed TNF-α-induced CXCL8 secretion by Caco-2 and DLD1 colonic epithelial cell lines and CXCL8 mRNA levels in Caco-2 cells. RNAi knockdown experiments indicated that the inhibitory effect was mediated by ROCK2, and not ROCK1. Inhibiting ROCK had no effect on TNF-stimulated IκBα phosphorylation and degradation or p38 MAPK phosphorylation indicating that ROCK plays no role in these signaling pathways. However, inhibiting ROCK suppressed TNF-induced phosphorylation of the p54 JNK isoform and phosphorylation of the upstream MKK4 kinase. These results suggest that ROCK is required for CXCL8 responses by TNF-stimulated IEC by affecting intracellular signaling through MKK4 and JNK.

Synthesis of benzothiophene-based hydroxamic acids as potent and selective HDAC6 inhibitors

A small library of 3-[(4-hydroxycarbamoylphenyl)aminomethyl]benzothiophenes was prepared, leading to the identification of three representatives as potent and selective HDAC6 inhibitors.