IL-1beta Production Research Articles

Actovegin\xae reduces PMA-induced inflammation on human cells

PurposeThe effect of Actovegin® was investigated on PMA- and LPS-induced human peripheral blood mononuclear cells (PBMCs).MethodsPBMCs (1 × 106 cells/ml) from five blood donors (2 f, 3 m; 45–55 years) were grown in medium and exposed to Actovegin® in the presence or absence of PMA or LPS. Supernatants were collected to assess the concentration of cytokines (TNF-α, IL-1beta, IL-6 and IL-10). The reactive oxygen species (ROS) were assessed by a ROS-GloTM H2O2 assay.ResultsStimulation of cells by PMA or LPS (without Actovegin®) significantly increased the secretion of IL-1beta, IL-6, IL-10 and TNF-α from PBMCs, compared to controls. Pre-treatment of cells with Actovegin® (1, 5, 25, 125 µg/ml) plus PMA significantly decreased the secretion of IL-1beta from PBMCs, compared to controls (PMA without Actovegin®). In contrast, addition of Actovegin® (1, 5, 25, 125 and 250 µg/ml) plus LPS did not alter the IL-1beta production, compared to controls (LPS without Actovegin®). TNF-α, IL-6 and IL-10 do not contribute to the reduction of inflammatory reactions with Actovegin®.ConclusionsActovegin® can reduce the PMA-induced IL-1beta release and the ROS production from PBMCs. These findings may help to explain the clinically known positive effects of Actovegin® on athletic injuries with inflammatory responses (e.g., muscle injuries, tendinopathies).

Endogenous oxidized phospholipids reprogram cellular metabolism and boost hyperinflammation

Abstract Pathogen-associated molecular patterns (PAMPs) have the capacity to couple inflammatory gene expression to changes in macrophage metabolism, both of which influence subsequent inflammatory activities. Similar to their microbial counterparts, several self-encoded damage-associated molecular patterns (DAMPs) induce inflammatory gene expression. However, whether this symmetry in host responses between PAMPs and DAMPs extends to metabolic shifts is unclear. Here we report that the self-encoded oxidized phospholipid oxPAPC alters the metabolism of macrophages exposed to lipopolysaccharide (LPS). While cells activated by LPS rely exclusively on glycolysis, macrophages exposed to oxPAPC also use mitochondrial respiration, feed the Krebs cycle with glutamine and favor the accumulation of oxaloacetate in the cytoplasm: this metabolite potentiates IL-1beta production, resulting in hyperinflammation. Similar metabolic adaptions occur in vivo in hypercholesterolemic mice and human subjects. Drugs that interfere with oxPAPC-driven metabolic changes reduce atherosclerotic plaque formation in mice, thereby underscoring the importance of DAMP-mediated activities in pathophysiological conditions.

NFKF is a synthetic fragment derived from rat hemopressin that protects mice from neurodegeneration

Previous studies suggested the pharmacological potential of rat hemopressin (PVNFKFLSH) and its shorter synthetic peptide NFKF, to protect from pilocarpine-induced seizures in mice. Orally administered NFKF was shown to be hundred times more potent than cannabidiol in delaying the first seizure induced by pilocarpine in mice. Here, using an experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis we have shown that C57BL/6 J mice orally administrated with NFKF (500 μg/kg) presented better EAE clinical scores and improved locomotor activity compared to saline administrated control mice. NFKF blocked the production of IL-1beta and IL-6, and has high scores binding cannabinoid type 2 receptors. Therefore, NFKF is an exciting new possibility to neurodegenerative diseases therapeutics.

EXTH-36. PI3K INHIBITION IN CONJUNCTION WITH THE KETOGENIC DIET REDUCES GROWTH AND NEUROINFLAMMATION IN PEDIATRIC HIGH-GRADE GLIOMA

Abstract Pediatric high-grade glioma remains a poorly treatable disease with high mortality. Targeted therapies have gained interest in this disease, but efficacy is limited by therapeutic resistance, often because of tumor heterogeneity. Phosphoinositide 3-kinase (PI3K) inhibitors represent a strong drug class for pediatric glioma, but their use is associated with insulin feedback that reactivates the PI3K pathway and drives therapeutic resistance. Here, we target insulin feedback that is the primary mechanism of PI3K inhibitor-related therapeutic resistance in pediatric high-grade glioma using the ketogenic diet. We treated patient-derived pediatric high-grade glioma stem cells with vehicle or the pan-PI3K inhibitor, BKM-120, in conjunction with phenformin to decrease glucose utilization. These cells exhibited 65% less proliferation when exposed to BKM-120 and phenformin. We treated NOD scid gamma (NSG) mice containing patient-derived pediatric high-grade glioma xenografts with vehicle or BKM-120 on a regular or ketogenic diet to determine whether reducing insulin feedback increases BKM-120 efficacy. Mice with intracranial glioma xenografts survived longer when treated with BKM-120 on the ketogenic diet than with BKM-120 or the ketogenic diet alone. We measured pro-inflammatory cytokines in glioma cells treated with BKM-120 and phenformin in comparison to vehicle-treated cells to determine their effect on neuro-inflammation. We also applied conditioned medium from glioma cells treated with BKM-120 and phenformin to cortical neurons to measure oxidative stress. We found that phenformin reduced the production of pro-inflammatory cytokines, including TNF-alpha, IFN-gamma, IL-1beta, and IL-6, by BKM-120-treated glioma cells. Cortical neurons treated with conditioned medium from BKM-120- and phenformin-treated glioma cells exhibited less oxidative stress than those treated with BKM-120 alone. Our results demonstrate that lowering glucose utilization and insulin feedback increases efficacy of PI3K inhibition and decreases neuro-inflammation. By using the ketogenic diet to reduce systemic glucose levels, this strategy may enhance efficacy and reduce morbidity of PI3K inhibitors in this population.

Altered monocyte phenotype and dysregulated innate cytokine responses among people living with HIV and opioid-use disorder.

Opioid-use disorders (OUD) and hepatitis C or B co-infection (HEP) are common among people living with HIV (PLHIV). The impact of OUD on innate and adaptive immunity among PLHIV with and without HEP is unknown. To investigate the impact of OUD on monocyte and T-cell phenotypes, cytokine responses to lipopolysaccharide (LPS) and phytohemagglutinin (PHA), and plasma inflammatory markers, among PLHIV with and without HEP. Cross-sectional study enrolling PLHIV receiving ART, with and without OUD. Flow cytometry determined monocyte and T-cell phenotypes; LPS and PHA-induced cytokine production was assessed following LPS and PHA stimulation by multiplex cytokine array; plasma IL-6, soluble CD163, and soluble CD14 were measured by ELISA. Twenty-two PLHIV with OUD and 37 PLHIV without OUD were included. PLHIV with OUD exhibited higher frequencies of intermediate (CD14CD16) and nonclassical (CD14CD16) monocytes when compared with PLHIV without OUD (P = 0.0025; P = 0.0001, respectively), regardless of HEP co-infection. Soluble CD163 and monocyte cell surface CD163 expression was increased among PLHIV with OUD and HEP, specifically. Regardless of HEP co-infection, PLHIV with OUD exhibited reduced production of IL-10, IL-8, IL-6, IL-1alpha, and TNF-alpha in response to LPS when compared with PLHIV without OUD; PHA-induced production of IL-10, IL-1alpha, IL-1beta, IL-6, and TNF-alpha were also reduced among individuals with OUD. OUD among PLHIV are associated with altered monocyte phenotypes and a dysregulated innate cytokine response. Defining underlying mechanisms of opioid-associated innate immune dysregulation among PLHIV should be prioritized to identify optimal OUD treatment strategies.

Semaphorin 3E regulates apoptosis in the intestinal epithelium during the development of colitis

Semaphorin 3E (SEMA3E) has emerged as an axon-guiding molecule that regulates various biological processes including the immune responses and apoptosis. However, its role in the pathophysiology of colitis remains elusive. We investigated the role of SEMA3E in intestinal epithelial cells (IECs) activation, using biopsies from patients with active ulcerative colitis (UC), a mouse model of UC, and an in-vitro model of intestinal mucosal healing. In this study, we confirmed that the mRNA level of SEMA3E is reduced significantly in patients with UC and demonstrated a negative linear association between SEMA3E mRNA and p53-associated genes. In mice, genetic deletion of Sema3e resulted in an increase onset and severity of colitis, p53-associated genes, apoptosis, and IL-1beta production. Recombinant SEMA3E treatment protected against colitis and decreased these effects. Furthermore, in stimulated epithelial cells, recombinant SEMA3E treatment enhanced wound healing, resistance to oxidative stress and decreased apoptosis and p53-associated genes. Together, these findings identify SEMA3E as a novel regulator in intestinal inflammation that regulates IECs apoptosis and suggest a potential novel approach to treat UC.

Abstract A152: Investigating metabolic basis of neurotoxicity during CAR-T therapies

Abstract Chimeric antigen receptor T (CAR-T) cell therapies are rapidly becoming first in line therapies for treatment of hematologic malignancies. This is due to the efficacy of the treatment and long-lasting tumor responses. However, CAR-T therapies are associated with unique set of acute toxicities— cytokine release syndrome (CRS) and neurologic toxicities—the cause of which is not clear. As other immune therapies are becoming more widely used, these toxicities are observed in patients undergoing bispecific T-cell engaging antibodies (BiTEs) and checkpoint blockade therapies. Here, we sought to define metabolic changes in patients undergoing chimeric antigen receptor (CAR) T-cell therapy for B-acute lymphoblastic leukemia. We performed metabolic analysis of amino acids in serum samples, and identified significant up-regulation of tryptophan-kynurenine metabolism in patients with high-grade neurotoxicity. In-depth look at tryptophan-kynurenine pathway in cerebrospinal fluid patient samples determined quinolinic acid up-regulation to correlate with low- and high-grade neurotoxicity, indicating local production of this metabolite. We show that quinolinic acid is produced by activated monocytes and microglia in response to Il1beta and TNF. Importantly, tryptophan metabolite—kynurenine— stimulates Il1beta production and further activation of monocytes, possibly exacerbating CSR and neurotoxicity. This study suggests that inhibition of tryptophan-kynurenine pathway may offer some benefit to manage neurotoxicity and CRS associated with CAR-T-cell therapy treatment. Citation Format: Darin Salloum, Bianca Santomasso, Renier J. Brentjens, Hans-Guido Wendel. Investigating metabolic basis of neurotoxicity during CAR-T therapies [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A152.

Beclin1-driven autophagy modulates the inflammatory response of microglia via NLRP3.

Alzheimer's disease is characterized not only by extracellular amyloid plaques and neurofibrillary tangles, but also by microglia-mediated neuroinflammation. Recently, autophagy has been linked to the regulation of the inflammatory response. Thus, we investigated how an impairment of autophagy mediated by BECN1/Beclin1 reduction, as described in Alzheimer's disease patients, would influence cytokine production of microglia. Acutely stimulated microglia from Becn1+/- mice exhibited increased expression of IL-1beta and IL-18 compared to wild-type microglia. Becn1+/-APPPS1 mice also contained enhanced IL-1beta levels. The investigation of the IL-1beta/IL-18 processing pathway showed an elevated number of cells with inflammasomes and increased levels of NLRP3 and cleaved CASP1/Caspase1 in Becn1+/- microglia. Super-resolation microscopy revealed a very close association of NLRP3 aggregates and LC3-positive vesicles. Interestingly, CALCOCO2 colocalized with NLRP3 and its downregulation increased IL-1beta release. These data support the notion that selective autophagy can impact microglia activation by modulating IL-1beta and IL-18 production via NLRP3 degradation and thus present a mechanism how impaired autophagy could contribute to neuroinflammation in Alzheimer's disease.

Qi-dan-di-huang decoction alleviates diabetic nephropathy by inhibiting the NF-kappaB pathway.

Diabetic nephropathy (DN) is one of the most serious complications of diabetes mellitus, for which no effective treatment currently exists. We tested the hypothesis that Qi-dan-di-huang (QDDH) might have therapuetic effects in an experimental rat model of DN. The levels of I kappa KinaseAlpha and Beta, p-p65, p-IκB alpha, TGF-β1 and Alpha-SMA were significantly increased in kidneys in DN. QDDH decoction only partially reversed the increased Ikappa KinaseAlpha/Beta, p-p65, p-IKappaB alpha, TGF-Beta1 and alpha-SMA in the kidneys in DN. However, treatment of diabetic rats with QDDH decoction significantly inhibited the production and release of inflammatory cytokines IL-6, IL-1 beta and TNF-alpha into the serum. QDDH decoction also significantly improved the physiologic and biochemical indicators of DN, reduced glycogen and protein deposition in DN and prevented renal fibrosis. Together, the data show that QDDH decoction exerts a protective effect on kidneys in diabetic rats and reverses the inflammatory milieu of the serum in DN.

The role of Cutibacterium acnes in auto-inflammatory bone disorders.

Chronic nonbacterial osteomyelitis (CNO) and SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome are auto-inflammatory disorders manifesting as chronic inflammation of bones and joints, which in SAPHO is often accompanying by skin changes. The aetiology of these diseases is unknown, but includes genetic, infectious and immunological components. It has been proposed that Cutibacterium (formerly Propionibacterium) acnes plays a role in the pathogenesis. In this review, we summarise reported cases of CNO or SAPHO syndrome in which C. acnes has been isolated from bones. To identify cases, a search was done in May 2018 using the MEDLINE Ovid interface (1946 to present). We found 14 publications reporting 98 patients with auto-inflammatory bone disorders, of whom 48 (49%) had positive bone biopsies for C. acnes. This bacteriumwas more frequently isolated from open biopsies than percutaneous ones (43/69 (62%) vs 1/7 (14%); p = 0.04) and biopsies were more frequently positive in patients who presented with simultaneous skin manifestations (19/36 (53%) vs 4/12 (33%); p = 0.03).Conclusion: In patients with CNO or SAPHO, C. acnes can be isolated from open biopsies suggesting that in these patients, C. acnes might be a pathogen rather than a contaminant. The fact that biopsies are more frequently positive in patients who present with simultaneous skin manifestations suggests that these individuals might have a genetic predisposition for impaired clearance of C. acnes. What is known • Chronic nonbacterial osteomyelitis (CNO) and SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome are auto-inflammatory disorders manifesting as inflammation of bones. Both diseases are an important differential diagnosis in children who present with symptoms of (multifocal) osteomyelitis. • The pathogenesis of CNO and SAPHO is multifactorial emcompassinggenetic, infectious and immunological components, including interleukin (IL)-1 dysregulation. There is a controversy as to whether Cutibacterium (formerly Propionibacterium) acnes plays a role in the aetiology of CNO and SAPHO. It has been postulated that the presence of C. acnes might trigger auto-inflammatory chronic inflammation in genetically predisposed individuals. What is new • In patients with CNO or SAPHO, C. acnes can be isolated more frequently from open biopsies, than from percutaneous ones, suggesting that C. acnes might be a pathogen rather than a contaminant. • Biopsies are more frequently positive in patients who present with simultaneous skin manifestations suggesting that these individuals might have a genetic predisposition for impaired clearance of C. acnes. Impaired C. acnes clearance likely leads to increased IL-1 beta (β) production by skin cells, bone cells and phagocytes, which is one of the main cytokines underlying chronic inflammatory bone disorders.

Genetic variant in IL-32 is associated with the ex vivo cytokine production of anti-TNF treated PBMCs from rheumatoid arthritis patients

About 60% of RA patients don’t achieve good response with biological disease-modifying anti-rheumatic drugs bDMARD treatment (including TNF inhibitors, TNFi’s). Previously, a link between TNFα and interleukin (IL)-32 was reported in RA. However, the exact mechanism linking IL-32 to response to treatment as not been studied yet. Therefore, we explored the influence of a promoter single nucleotide polymorphism (SNP) rs4786370 in IL-32 on clinical responsiveness to TNFi’s in RA patients, potentially serving as new biomarker in RA. Expression of pro-inflammatory cytokines by peripheral mononuclear cells (PBMCs) from RA patients and healthy individuals were studied. Moreover, “ex vivo response” and clinical response to anti-TNFα therapy (etanercept, adalimumab) were measured and stratified for the IL-32 SNP. Higher IL-32 protein production was observed in RA patients. Additionally, patients bearing the CC genotype showed higher IL-32 protein and cytokine expression. DAS28 was independent of the promoter SNP, however, the “ex vivo” cytokine response was not. IL-32 mRNA and protein production was higher in RA patients, with a trend towards higher concentrations in patients bearing the CC genotype. Furthermore, genotype dependent IL-1 beta production might predict clinical response to etanercept/adalimumab. This indicates that IL-32 could play a role in predicting response to treatment in RA.

Abstract A26: The metastatic potential of breast cancer cells was suppressed by NLRP3 inflammasome inhibition in macrophages

Abstract Tumor microenvironment favors tumor cells to promote tumor growth, migration, invasion, and angiogenesis. IL-1beta, one of the inflammatory cytokines associated with tumor microenvironment, plays an important role in the development and progress of tumor. The activation of inflammasome is critical to secrete mature IL-1beta through stepwise reactions to activate capspase-1. Therefore, we investigated whether the metastatic potential of breast cancer cells was regulated by NLRP3 inflammasome activation of macrophages in tumor microenvironment. The activation of NLRP3 inflammasome was induced by ATP in bone marrow-derived primary mouse macrophages. The metastatic potential of 4T1 breast cancer cells was determined by migration and invasion assays with transwell system. Conditioned media from ATP-stimulated wild-type macrophages increased the migration and invasion of breast cancer cells (4T1) while conditioned media from NLRP3 knockout macrophages stimulated with ATP failed to induce the migration and invasion of breast cancer cells. Celastrol, an inhibitor of NLRP3 inflammasome, reduced the potency of macrophages to stimulate the migration and invasion of 4T1 breast cancer cells. The suppression of NLRP3 inflammasome by celastrol was mediated by the blockade of potassium efflux. The results demonstrate that the activation of NLRP3 inflammasome in macrophages leads to the enhancement of metastatic potential of breast cancer cells. The results would provide a novel anticancer strategy to modulate tumor microenvironment by suppressing NLRP3 inflammasome and consequently reducing IL-1beta production. (This study was supported by the National Research Foundation of Korea (NRF) grants funded by the Korea government (Bio & Medical Technology Development Program, NRF-2017M3A9F5028608; Basic Research Laboratory Program, NRF-2017R1A4A1015036.) Citation Format: Jin Y. Lee, Hye E. Lee, Joo Y. Lee. The metastatic potential of breast cancer cells was suppressed by NLRP3 inflammasome inhibition in macrophages [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A26.

Induction of NLRP3 inflammasome activation by heme in human endothelial cells

Aim: Atherosclerosis, a chronic inflammatory disease is characterized by increased level of IL-1beta. Hemolytic or hemorrhagic episodes are often associated with inflammation. Heme released from RBCs is a DAMP and induce IL-1beta production through the activation of NLRP3 inflammasome in macrophages, however other cellular targets of heme-mediated inflammasome activation were not investigated.

Histone h4 as a trigger for innate immune cells.

Abstract Extracellular histones have been considered to be responsible for several systemic inflammatory injuries, including lung, kidney and liver. We now show that histone H4 can directly activate neutrophil respiratory burst response, depolarization, and myeloperoxidase (MPO) release. In addition, histone H4 increased neutrophil adhesion activity and the expression of adhesion molecule. More interestingly, we found that histone H4 also induced a sustained rise in the intracellular calcium level in neutrophils, and that H4 increased caspase 3 activity in neutrophils over time, which can be inhibited by anti-H4 antibody treatment. Histone H4 induced IL-8 release from neutrophils and is also a strong inducer of IL-1 beta and TNF-alpha productions in monocytes and monocyte-derived macrophages. To counteract the effects of histone H4, we found that C reactive protein (CRP) and/or surfactant protein D (SP-D) could reduce histone H4-induced respiratory burst response, calcium flux, MPO release and caspase 3 activity in neutrophils. These findings suggest that extracellular histone H4 may play important roles in the innate immunity, and some endogenous peptides may have the ability to reduce H4-induced effects. This study will hopefully provide new treating targets for treating inflammatory diseases and novel strategies based on modification of CRP or SP-D with optimal histone binding site for treatment of severe infections.

Altered Glutathione Homeostasis in NLRP3 Inflammasome Activation Mediated by ATP-P2X7 Receptor Signaling

NLRP3 inflammasome is an intracellular protein complex of which activation is responsible for maturation of pro-inflammatory cytokines such as interleukin-1beta (IL-1beta) and IL-18. Full activation of NLRP3 inflammasome requires two distinct steps; expression of component proteins as well as pro-IL-1beta induced by pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS), followed by complex formation activated by damage-associated molecular patterns (DAMPs) such as ATP. Although redox-dependent regulation of the complex formation has been suggested, it remains unclear how cellular redox status is regulated during ATP stimulation in cells. Here we describe that glutathione (GSH), an antioxidant peptide abundantly present in cells, plays an important role in ATP-dependent inflammasome activation. LC-MSMS analyses clearly demonstrated that cellular levels of GSH were rapidly decline upon ATP stimulation in LPS-primed mouse macrophage J774.1 cells. Similar levels of GSH were detected in the culture supernatants suggesting that ATP stimulated GSH efflux. It should be noted that ATP treatment also induced efflux of polysulfurated derivatives of GSH such as GSSH and GSSSH as well. P2X7 receptor antagonist A-804598 treatment remarkably inhibited both IL-1beta production as well as decrease of GSH. GSH or its oxidized form GSSG added extracellularly suppressed ATP-dependent decline of intracellular GSH, and more importantly, IL-1beta production. Analyses with use of ROS-sensitive probe DCDHF-DA revealed that ATP stimulation augmented ROS production in macrophages, and it was cancelled in the presence of GSSG. Thus, macrophages use ATP-P2X7 receptor signaling to modulate GSH homeostasis via GSH efflux, thereby regulating redox balance for the inflammasome activation.

Involvement of caspase-4 in IL-1 beta production and pyroptosis in human macrophages during dengue virus infection

Caspase-4 physically interacts with caspase-1 and is believed to be a proinflammatory caspase that can induce the inflammatory form of programmed cell death (pyroptosis) and the release of mature interleukin (IL)-1β. However, the function of caspase-4 in dengue virus infection is not yet fully understood. We examined the function of caspase-4 in IL-1β production and pyroptosis during dengue virus serotype-2 (DENV-2) infection in human macrophages. In this study, DENV-2 infection increased IL-1β protein level with activated caspase-4 activity. Using primary macrophages, we observed that caspase-4 induces activation of caspase-1 and secretion of IL-1β in response to DENV-2 infection, without the need for secondary signals to stimulate the assembly of the inflammasome. These findings indicate that the regulation of caspase-1 activity by capsase-4 could represent a unique mechanism. Our data suggest that caspase-4 is upstream of caspase-1 in the pathway that regulates pyroptosis and IL-1β synthesis in macrophages during DENV-2 infection.

The microbiota-derived metabolite indole is an endogenous regulator of autophagy

Abstract Autophagy is an evolutionarily conserved cellular mechanism that is crucial for promoting cell survival, pathogen clearance, and homeostasis. Dysregulated autophagy destabilizes GI tract homeostasis, promotes Crohn’s Disease, and perturbs the microbiota, a prominent feature during gut inflammation. Classically, energy substrate starvation induces cellular autophagy, yet host dietary intake makes the GI tract nutritionally abundant. Thus, the discrete gut signals able to induce autophagy and overcome the cues from a fully energy replete environment remain largely unknown. Here we demonstrate that indole, a strictly microbiota-derived metabolite, induces autophagy at a level comparable with the canonical autophagy-inducer rapamycin. Consistent with the induction of autophagy, indole-conditioned dendritic cells exhibited increased LC3-II expression and puncta formation, enhanced bacterial killing, and reduced inflammasome activity. Indole effects were largely similar to rapamycin yet also distinct, suggesting a complementary mechanism of action for these molecules. Both indole and rapamycin suppressed mTOR signaling and IL-1beta production, suggesting a functional link. Unlike rapamycin, we have reported indole is a ligand of the aryl hydrocarbon receptor (AhR), yet regulation of autophagy by indole was AhR-independent. To our knowledge, this is the first evidence of a tryptophan microbiota metabolite functioning as a regulator of autophagy. These findings reveal novel biology by which the microbiota regulates gut autophagy and has therapeutic implications in inflammatory and autophagy-mediated disorders.

Macrophage Migration Inhibitory Factor Serves As an Upstream Regulator of NLRP3 Expression and Subsequent IL-1beta Production in Human Monocytes in Response to Lupus U1-snRNP Immune Complex

Abstract The pathologic hallmarks of systemic lupus erythematosus (SLE or lupus) are altered immune responses to nuclear autoantigens with autoantibody production and subsequent tissue injury. TLR7/8 recognize the ssRNA of the self-antigen U1-small nuclear ribonucleorprotein (U1-snRNP) that is targeted by anti-U1-snRNP antibodies (Abs) in lupus. Recently, we showed IL-1β production from human monocytes (MO) exposed to a combination of U1-snRNP and anti-U1-snRNP Abs (snRNP immune complexes) via the NLRP3 inflammasome. Macrophage migration inhibitory factor (MIF), primarily produced from MO and macrophages, promotes the production of IL-1β, IL-6 and TNF-α, which are increased in lupus patients. Data showed an association between serum MIF levels and MIF gene polymorphisms with lupus-related organ damage and decreased glomerulonephritis in lupus-prone mice treated with MIF antagonists. Here we investigated the possible mechanisms underlying the functional link between MIF and the NLRP3 inflammasome. The snRNP immune complexes (ICs) induced high levels of MIF and IL-1β from freshly purified human MO. The small molecule MIF inhibitor MIF098, which interferes the binding of MIF to its receptor complex, decreased the production of IL-1β from MO in response to the snRNP ICs. The inhibitor substantially reduced the expression of NLRP3 and caspase-1 activation. This phenomenon is likely mediated in part by the suppression of NF-kB activation. Plus, exogenous MIF increased IL-1β production by the MO. Our results first show the production of MIF from MO by the lupus snRNP IC and the regulation of the NLRP3 inflammasome by MIF in human, providing a scientific rationale for translating animal studies targeting MIF into human lupus.

Glucose-induced β cell production of IL-1β contributes to glucotoxicity in human pancreatic islets.

In type 2 diabetes, chronic hyperglycemia is suggested to be detrimental to pancreatic beta cells, causing impaired insulin secretion. IL-1beta is a proinflammatory cytokine acting during the autoimmune process of type 1 diabetes. IL-1beta inhibits beta cell function and promotes Fas-triggered apoptosis in part by activating the transcription factor NF-kappaB. Recently, we have shown that increased glucose concentrations also induce Fas expression and beta cell apoptosis in human islets. The aim of the present study was to test the hypothesis that IL-1beta may mediate the deleterious effects of high glucose on human beta cells. In vitro exposure of islets from nondiabetic organ donors to high glucose levels resulted in increased production and release of IL-1beta, followed by NF-kappaB activation, Fas upregulation, DNA fragmentation, and impaired beta cell function. The IL-1 receptor antagonist protected cultured human islets from these deleterious effects. beta cells themselves were identified as the islet cellular source of glucose-induced IL-1beta. In vivo, IL-1beta-producing beta cells were observed in pancreatic sections of type 2 diabetic patients but not in nondiabetic control subjects. Similarly, IL-1beta was induced in beta cells of the gerbil Psammomys obesus during development of diabetes. Treatment of the animals with phlorizin normalized plasma glucose and prevented beta cell expression of IL-1beta. These findings implicate an inflammatory process in the pathogenesis of glucotoxicity in type 2 diabetes and identify the IL-1beta/NF-kappaB pathway as a target to preserve beta cell mass and function in this condition.

Topical thioredoxin inhibits IL-6 and IL-1beta production from keratinocytes and is effective for psoriasis-like dermatitis in mice

Topical thioredoxin inhibits IL-6 and IL-1beta production from keratinocytes and is effective for psoriasis-like dermatitis in mice