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Concept: Interleukin 1


Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the “inflammatory reflex,” is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases.

Concepts: Inflammation, Cytokine, Interleukin 1, Rheumatoid arthritis, Vagus nerve, Autoimmune disease, Vagus nerve stimulation, Tumor necrosis factor-alpha


There is strong diurnal variation in the symptoms and severity of chronic inflammatory diseases, such as rheumatoid arthritis. In addition, disruption of the circadian clock is an aggravating factor associated with a range of human inflammatory diseases. To investigate mechanistic links between the biological clock and pathways underlying inflammatory arthritis, mice were administered collagen (or saline as a control) to induce arthritis. The treatment provoked an inflammatory response within the limbs, which showed robust daily variation in paw swelling and inflammatory cytokine expression. Inflammatory markers were significantly repressed during the dark phase. Further work demonstrated an active molecular clock within the inflamed limbs and highlighted the resident inflammatory cells, fibroblast-like synoviocytes (FLSs), as a potential source of the rhythmic inflammatory signal. Exposure of mice to constant light disrupted the clock in peripheral tissues, causing loss of the nighttime repression of local inflammation. Finally, the results show that the core clock proteins CRYPTOCHROMES 1 and 2 repressed inflammation within the FLSs, and provide novel evidence that a CRYPTOCHROME activator has anti-inflammatory properties in human cells. We conclude that under chronic inflammatory conditions, the clock actively represses inflammatory pathways during the dark phase. This interaction has exciting potential as a therapeutic avenue for treatment of inflammatory disease.-Hand, L. E., Hopwood, T. W., Dickson, S. H., Walker, A. L., Loudon, A. S. I., Ray D. W., Bechtold, D. A., Gibbs, J. E. The circadian clock regulates inflammatory arthritis.

Concepts: Inflammation, Interleukin 1, Asthma, Rheumatoid arthritis, Vasculitis, Anti-inflammatory, Circadian rhythm, C-reactive protein


Six volunteers experienced severe inflammatory response during the Phase I clinical trial of a monoclonal antibody that was designed to stimulate a regulatory T cell response. Soon after the trial began, each volunteer experienced a “cytokine storm”, a dramatic increase in cytokine concentrations. The monoclonal antibody, TGN1412, raised serum concentrations of both pro- and anti-inflammatory cytokines το very hiγh values during the first day, while lymphocyte and monocyte concentrations plummeted. Because the subjects were healthy and had no prior indications of immune deficiency, this event provided an unusual opportunity to study the dynamic interactions of cytokines and other measured parameters. Here, the response histories of nine cytokines have been modeled by a set of linear ordinary differential equations. A general search procedure identifies parameters of the model, whose response fits the data well during the five-day measurement period. The eighteenth-order model reveals plausible cause-and-effect relationships among the cytokines, showing how each cytokine induces or inhibits other cytokines. It suggests that perturbations in IL2, IL8, and IL10 have the most significant inductive effect, while IFN-γ and IL12 have the greatest inhibiting effect on other cytokine concentrations. Although TNF-α is a major pro-inflammatory factor, IFN-γ and three other cytokines have faster initial and median response to TGN1412 infusion. Principal-component analysis of the data reveals three clusters of similar cytokine responses: [TNF-α, IL1, IL10], [IFN-γ, IL2, IL4, IL8, and IL12], and [IL6]. IL1, IL6, IL10, and TNF-α have the highest degree of variability in response to uncertain initial conditions, exogenous effects, and parameter estimates. This study illuminates details of a cytokine storm event, and it demonstrates the value of linear modeling for interpreting complex, coupled biological system dynamics from empirical data.

Concepts: Immune system, Inflammation, Antibody, Cytokine, Interleukin 1, Cytokine storm, Ordinary differential equation, TGN1412


Chronic inflammatory diseases such as arthritis are characterized by dysregulated responses to pro-inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor α (TNF-α). Pharmacologic anti-cytokine therapies are often effective at diminishing this inflammatory response but have significant side effects and are used at high, constant doses that do not reflect the dynamic nature of disease activity. Using the CRISPR/Cas9 genome-engineering system, we created stem cells that antagonize IL-1- or TNF-α-mediated inflammation in an autoregulated, feedback-controlled manner. Our results show that genome engineering can be used successfully to rewire endogenous cell circuits to allow for prescribed input/output relationships between inflammatory mediators and their antagonists, providing a foundation for cell-based drug delivery or cell-based vaccines via a rapidly responsive, autoregulated system. The customization of intrinsic cellular signaling pathways in stem cells, as demonstrated here, opens innovative possibilities for safer and more effective therapeutic approaches for a wide variety of diseases.

Concepts: Immune system, Inflammation, Medicine, Interleukin 1, Infection, Rheumatoid arthritis, Anti-inflammatory, Tumor necrosis factor-alpha


Levels of inflammatory mediators in circulation are known to increase with age, but the underlying cause of this age-associated inflammation is debated. We find that, when maintained under germ-free conditions, mice do not display an age-related increase in circulating pro-inflammatory cytokine levels. A higher proportion of germ-free mice live to 600 days than their conventional counterparts, and macrophages derived from aged germ-free mice maintain anti-microbial activity. Co-housing germ-free mice with old, but not young, conventionally raised mice increases pro-inflammatory cytokines in the blood. In tumor necrosis factor (TNF)-deficient mice, which are protected from age-associated inflammation, age-related microbiota changes are not observed. Furthermore, age-associated microbiota changes can be reversed by reducing TNF using anti-TNF therapy. These data suggest that aging-associated microbiota promote inflammation and that reversing these age-related microbiota changes represents a potential strategy for reducing age-associated inflammation and the accompanying morbidity.

Concepts: Immune system, Inflammation, Bacteria, Cytokine, Interleukin 1, Atherosclerosis, Apoptosis, Tumor necrosis factor-alpha


Diets rich in fruits and vegetables (FV), which contain (poly)phenols, protect against age-related inflammation and chronic diseases. T-lymphocytes contribute to systemic cytokine production and are modulated by FV intake. Little is known about the relative potency of different (poly)phenols in modulating cytokine release by lymphocytes. We compared thirty-one (poly)phenols and six (poly)phenol mixtures for effects on pro-inflammatory cytokine release by Jurkat T-lymphocytes. Test compounds were incubated with Jurkat cells for 48 h at 1 and 30 µm, with or without phorbol ester treatment at 24 h to induce cytokine release. Three test compounds that reduced cytokine release were further incubated with primary lymphocytes at 0·2 and 1 µm for 24 h, with lipopolysaccharide added at 5 h. Cytokine release was measured, and generation of H2O2 by test compounds was determined to assess any potential correlations with cytokine release. A number of (poly)phenols significantly altered cytokine release from Jurkat cells (P<0·05), but H2O2 generation did not correlate with cytokine release. Resveratrol, isorhamnetin, curcumin, vanillic acid and specific (poly)phenol mixtures reduced pro-inflammatory cytokine release from T-lymphocytes, and there was evidence for interaction between (poly)phenols to further modulate cytokine release. The release of interferon-γ induced protein 10 by primary lymphocytes was significantly reduced following treatment with 1 µm isorhamnetin (P<0·05). These results suggest that (poly)phenols derived from onions, turmeric, red grapes, green tea and açai berries may help reduce the release of pro-inflammatory mediators in people at risk of chronic inflammation.

Concepts: Inflammation, Antibody, Cytokine, Interleukin 1, Enzyme, Asthma, Interleukin, Module


In autoimmune disease, a network of diverse cytokines is produced in association with disease susceptibility to constitute the ‘cytokine milieu’ that drives chronic inflammation. It remains elusive how cytokines interact in such a complex network to sustain inflammation in autoimmune disease. This has presented huge challenges for successful drug discovery because it has been difficult to predict how individual cytokine-targeted therapy would work. Here, we combine the principles of Chinese Taoism philosophy and modern bioinformatics tools to dissect multiple layers of arbitrary cytokine interactions into discernible interfaces and connectivity maps to predict movements in the cytokine network. The key principles presented here have important implications in our understanding of cytokine interactions and development of effective cytokine-targeted therapies for autoimmune disorders.

Concepts: Pharmacology, Medicine, Bioinformatics, Interleukin 1, Interleukin, Autoimmune disease, Graves' disease, Taoism


OBJECTIVE: The aim of this preliminary study was analyze the possible alterations in some salivary interleukins, usually associated with the inflammatory processes. MATERIAL AND METHODS: The study comprised three groups: group 1, with 26 cases with bisphosphonates-related osteonecrosis of the jaws (BRONJ). Group 2, with 29 patients who had received iBF but without BRONJ. Group 3, with 26 control patients not treated with BF and without oral lesions. We collected unstimulated whole saliva in all groups. A semiquantitative study was performed based on a cytokine array panel. We used the proteome profiler array for the study. We analyzed: Interleukin 1 alpha (IL-1α), interleukin-1 receptor antagonist (IL-1RA), and interleukin 1 beta (IL-1β). RESULTS: We found higher salivary values for all the cytokines studied in group 1 than in group 2 and 3. IL-1β showed the major differences compared with control group. (P < 0.05) CONCLUSIONS: This preliminary study confirms that there are alterations in these interleukins in patients with BRONJ. These results give support to further additional salivary studies on these biomarkers by quantitative measures.

Concepts: Inflammation, Cytokine, Interleukin 1, Cytokines, Sociology, Interleukin 10, Interleukin, Interleukin-1 receptor


Interleukin-1 is one of the inflammatory cytokines elevated after traumatic joint injury that plays a critical role in mediating cartilage tissue degradation, suppressing matrix biosynthesis, and inducing chondrocyte apoptosis, events associated with progression to post-traumatic osteoarthritis (PTOA). We studied the combined use of insulin-like growth factor-1 (IGF-1) and dexamethasone (Dex) to block these multiple degradative effects of cytokine challenge to articular cartilage.

Concepts: Cytokine, Interleukin 1, Apoptosis, Cartilage, Osteoarthritis, Insulin-like growth factor 1, Growth hormone, Knee


Recent studies suggest a role for autophagy in the secretion of IL-1 cytokines regulating the development of inflammatory diseases. The antimalarial drug and autophagy/lysosome inhibitor chloroquine (CHQ) is considered as potential trigger of drug-induced or drug-aggravated psoriasis, in which Th17 cells sustain a persistent inflammation. In this study, we investigated the effect of CHQ on human monocyte-derived Langerhans-like cells (MoLC) and dendritic cells (MoDC) in response to IL-1β. The presence of CHQ reduced IL-12p70 release in both subsets, but surprisingly increased IL-6 production in MoDC and IL-23 in MoLC. Importantly, CHQ-treated MoLC promoted IL-17A secretion by CD4(+) T cells and elevated RORC mRNA levels, whereas IFN-γ release was reduced. The dysregulation of IL-12 family cytokines in MoLC and MoDC occurred at the transcriptional level. Similar effects were obtained with other late autophagy inhibitors, whereas PI3K inhibitor 3-methyladenine failed to increase IL-23 secretion. The modulated cytokine release was dependent on IL-1 cytokine activation and abrogated by a specific IL-1R antagonist. CHQ elevated expression of TNFR-associated factor 6, a common intermediate in IL-1R and TLR-dependent signaling. Accordingly, treatment with Pam3CSK4 and CHQ enhanced IL-23 release in MoLC and MoDC. CHQ inhibited autophagic flux, confirmed by increased LC3-II and p62 expression, and activated ERK, p38, and JNK MAPK, but only inhibition of p38 abrogated IL-23 release by MoLC. Thus, our findings indicate that CHQ modulates cytokine release in a p38-dependent manner, suggesting an essential role of Langerhans cells and dendritic cells in CHQ-provoked psoriasis, possibly by promoting Th17 immunity.

Concepts: Inflammation, Gene expression, Interleukin 1, Interleukin 17, Interleukin, Enzyme inhibitor, Inhibitor, Antimalarial drug