IL-1β Production Research Articles

Tryptanthrin suppresses multiple inflammasome activation to regulate NASH progression by targeting ASC protein

BackgroundThe adaptor protein apoptosis-associated speck-like protein (ASC) containing a caspase recruitment domain (CARD) can be activated through pyrin domain (PYD) interactions between sensors and ASC, and through CARD interactions between caspase-1 and ASC. Although the majority of ternary inflammasome complexes depend on ASC, drugs targeting ASC protein remain scarce. After screening natural compounds from Isatidis Radixin, we found that tryptanthrin (TPR) could inhibit NLRP3-induced IL-1β and caspase-1 production, but the underlying anti-inflammatory mechanisms remain to be elucidated. PurposeThe purpose of this study was to determine the impact of TPR on the NLRP3, NLRC4, and AIM2 inflammasomes and the underlying mechanisms. Additionally, the efficacy of TPR was analysed in the further course of methionine- and choline-deficient (MCD)–induced NASH and lipopolysaccharide (LPS)–induced sepsis models of mice. MethodsIn vitro studies used bone marrow-derived macrophages to assess the anti-inflammatory activity of TPR, and the techniques included western blot, testing of intracellular K+ and Ca2+, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), co-immunoprecipitation, ASC oligomerization assay, surface plasmon resonance (SPR), and molecular docking. We used LPS-induced sepsis models and MCD-induced NASH models in vivo to evaluate the effectiveness of TPR in inhibiting inflammatory diseases. ResultsOur observations suggested that TPR could inhibit NLRP3, NLRC4, and AIM2 inflammasome activation. As shown in a mouse model of inflammatory diseases caused by MCD-induced NASH and LPS-induced sepsis, TPR significantly alleviated the progression of diseases. TPR interrupted the interactions between ASC and NLRP3/NLRC4/AIM2 in the co-immunoprecipitation experiment, and stable binding of TPR to ASC was also evident in SPR experiments. The underlying mechanisms of anti-inflammatory activities of TPR might be associated with targeting ASC, in particular, PYD domain of ASC. ConclusionIn general, the requirement for ASC in multiple inflammasome complexes makes TPR, as a novel broad-spectrum inflammasome inhibitor, potentially useful for treating a wide range of multifactorial inflammasome-related diseases.

Inflammatory Cytokine-Induced Muscle Atrophy and Weakness Can Be Ameliorated by an Inhibition of TGF-β-Activated Kinase-1.

Chronic inflammation causes muscle wasting. Because most inflammatory cytokine signals are mediated via TGF-β-activated kinase-1 (TAK1) activation, inflammatory cytokine-induced muscle wasting may be ameliorated by the inhibition of TAK1 activity. The present study was undertaken to clarify whether TAK1 inhibition can ameliorate inflammation-induced muscle wasting. SKG/Jcl mice as an autoimmune arthritis animal model were treated with a small amount of mannan as an adjuvant to enhance the production of TNF-α and IL-1β. The increase in these inflammatory cytokines caused a reduction in muscle mass and strength along with an induction of arthritis in SKG/Jcl mice. Those changes in muscle fibers were mediated via the phosphorylation of TAK1, which activated the downstream signaling cascade via NF-κB, p38 MAPK, and ERK pathways, resulting in an increase in myostatin expression. Myostatin then reduced the expression of muscle proteins not only via a reduction in MyoD1 expression but also via an enhancement of Atrogin-1 and Murf1 expression. TAK1 inhibitor, LL-Z1640-2, prevented all the cytokine-induced changes in muscle wasting. Thus, TAK1 inhibition can be a new therapeutic target of not only joint destruction but also muscle wasting induced by inflammatory cytokines.

Intervention with fructooligosaccharides, Saccharomyces boulardii, and their combination in a colitis mouse model.

To examine the effects of an intervention with fructooligosaccharides (FOS), Saccharomyces boulardii, and their combination in a mouse model of colitis and to explore the mechanisms underlying these effects. The effects of FOS, S. boulardii, and their combination were evaluated in a DSS-induced mouse model of colitis. To this end, parameters such as body weight, the disease activity index (DAI), and colon length were examined in model mice. Subsequently, ELISA was employed to detect the serum levels of proinflammatory cytokines. Histopathological analysis was performed to estimate the progression of inflammation in the colon. Gas chromatography was used to determine the content of short-chain fatty acids (SCFAs) in the feces of model mice. Finally, 16S rRNA sequencing technology was used to analyze the gut microbiota composition. FOS was slight effective in treating colitis and colitis-induced intestinal dysbiosis in mice. Meanwhile, S. boulardii could significantly reduced the DAI, inhibited the production of IL-1β, and prevented colon shortening. Nevertheless, S. boulardii treatment alone failed to effectively regulate the gut microbiota. In contrast, the combined administration of FOS/S. boulardii resulted in better anti-inflammatory effects and enabled microbiota regulation. The FOS/S. boulardii combination (109 CFU/ml and 107 CFU/ml) significantly reduced the DAI, inhibited colitis, lowered IL-1β and TNF-α production, and significantly improved the levels of butyric acid and isobutyric acid. However, FOS/S. boulardii 109 CFU/ml exerted stronger anti-inflammatory effects, inhibited IL-6 production and attenuated colon shortening. Meanwhile, FOS/S. boulardii 107 CFU/ml improved microbial regulation and alleviated the colitis-induced decrease in microbial diversity. The combination of FOS and S. boulardii significantly increased the abundance of Parabacteroides and decreased the abundance of Escherichia-Shigella. Additionally, it promoted the production of acetic acid and propionic acid. Compared with single administration, the combination can significantly increase the abundance of beneficial bacteria such as lactobacilli and Bifidobacteria and effectively regulate the gut microbiota composition. These results provide a scientific rationale for the prevention and treatment of colitis using a FOS/S. boulardii combination. They also offer a theoretical basis for the development of nutraceutical preparations containing FOS and S. boulardii.

Probing Isosteric Replacement for Immunoadjuvant Design: Bis-Aryl Triazole Trehalolipids are Mincle Agonists.

Herein, we report the modular synthesis and immunological activity of seven bis-aryl triazole trehalolipids (1a-1g) as Brartemicin analogs. The compounds comprised one or two octyloxy (C8) alkyl chains and were synthesized using the venerable CuAAc reaction between the respective aryl acetylenes and a trehalose diazide. A Mincle reporter cell assay revealed that all lipidated analogs activated Mincle. Two compounds, 1c and 1d, produced strong Mincle-dependent immune responses in vitro. The activity was dependent on the degree of alkylation and regiochemistry, with 1c and 1d showing significantly increased IL-1β production in vitro compared to monoalkylated compounds and dialkylated compounds lacking ortho substitution. Molecular docking of 1c positioned the triazole in proximity to Arg-183, which may offer additional interactions that could explain the binding affinity for this class of ligand. These findings demonstrate the capability of triazole-linked Brartemicin analogs as Mincle-mediated Th1/Th17 vaccine adjuvants.

Limosilactobacillus reuteri supernatant attenuates inflammatory responses of human gingival fibroblasts to LPS but not to elevated glucose levels.

We investigated the invitro effect of Limosilactobacillus reuteri DSM 17938 supernatant on the inflammatory response of human gingival fibroblasts (HGF) challenged by lipopolysaccharide (LPS) or elevated glucose levels. HGF were exposed to LPS (1 μg/mL), glucose (5, 12 mM or 25 mM), and dilutions of supernatant prepared from L. reuteri DSM 17938 (0.5 × 107, 1.0 × 107, 2.5 × 107, and 5.0 × 107 CFU/mL). After 24 h cell viability and levels of cytokines (IL-1β, IL-6 and IL-8) and TLR-2 were determined. None of the tested L. reuteri (DSM 17938) supernatant concentrations reduced the viability of HGF. Supernatant concentrations (2.5 × 107 and 5 × 107 CFU/mL) significantly (p < .05) decreased the production of IL-1β, IL-6, IL-8, and TLR-2 in the presence of LPS. In contrast, inflammatory markers were not reduced by L. reuteri supernatant in the presence of glucose. Glucose concentrations of 12 mM and 24 mM still lead to an elevated production of the investigated biochemical mediators. While L. reuteri (DSM 17938) supernatant attenuates the inflammatory response of HGF to LPS in a dose-dependent manner, elevated glucose levels suppress this action. These invitro results support the overall anti-inflammatory efficacy of L. reuteri supplementation in plaque-associated periodontal inflammations.

Investigating the effects of rare ginsenosides on hyperuricemia and associated sperm damage via nontargeted metabolomics and gut microbiota

Ethnopharmacological relevanceIn ancient times, ginseng was used for hyperuricemia treatment as described in the classic traditional Chinese medical text Shang Han Lun. Recent studies have shown that common ginsenosides and rare ginsenosides (RGS) are the main active compounds in ginseng. RGS have higher activity and are less studied in the treatment of hyperuricemia. Aim of the studyTo determine whether RGS prevents and ameliorates potassium oxonate(PO)-induced hyperuricemia and concomitant spermatozoa damage in mice and the possible underlying mechanisms. Materials and methodsPotassium oxonate (PO, 300 mg/kg) induced hyperuricemia in mice via the oral administration of RGS (50, 100, or 200 mg/kg) or allopurinol (ALL, 5 mg/kg) for 35 days. Uric acid (UA) and xanthine oxidase (XO) levels were measured to assess the degree of histopathological damage in the liver, kidney, and testis, and renal creatinine (CRE), urea nitrogen (BUN), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and inflammatory factor (IL-1β) levels were measured to calculate the sperm density. Mechanisms were also explored based on blood and urine metabolomics and the gut microbiota. ResultsIn this study, we demonstrated that RGS containing Rg3, Rk1, Rg6, and Rg5 could reduce serum UA levels, inhibit serum and hepatic XO activity, reduce renal CRE and BUN levels, further restore renal SOD and GSH activities, reduce the accumulation of MDA in the kidneys, and attenuate the production of renal IL-1β. RGS was able to restore sperm density. Metabolomic analysis revealed that RGS improved sphingolipid metabolism, pyrimidine metabolism, and other metabolic pathways. 16S rDNA sequencing revealed that RGS could increase gut microbial diversity, restore the Firmicutes/Bacteroidetes (F/B) ratio, and adjust the intestinal microbial balance. Spearman's correlation analysis revealed a correlation between differentially metabolites and the gut microbiota. Lactobacillus and Akkermansia are the core genera. ConclusionRGS can be a candidate for the prevention and amelioration of hyperuricemia and concomitant sperm damage. Its mechanism of action is closely related to sphingolipid metabolism, pyrimidine metabolism, and the modulation of gut microbiota, such as Lactobacillus and Akkermansia.

Phytochemical Composition, Anti-Inflammatory Property, and Anti-Atopic Effect of Chaetomorpha linum Extract.

Utilizing plant-based resources, particularly their by-products, aligns with sustainability principles and circular bioeconomy, contributing to environmental preservation. The therapeutic potential of plant extracts is garnering increasing interest, and this study aimed to demonstrate promising outcomes from an extract obtained from an underutilized plant waste. Chaetomorpha linum, an invasive macroalga found in the Orbetello Lagoon, thrives in eutrophic conditions, forming persistent mats covering approximately 400 hectares since 2005. The biomass of C. linum undergoes mechanical harvesting and is treated as waste, requiring significant human efforts and economic resources-A critical concern for municipalities. Despite posing challenges to local ecosystems, the study identified C. linum as a natural source of bioactive metabolites. Phytochemical characterization revealed lipids, amino acids, and other compounds with potential anti-inflammatory activity in C. linum extract. In vitro assays with LPS-stimulated RAW 264.7 and TNF-α/IFN-γ-stimulated HaCaT cells showed the extract inhibited reactive oxygen species (ROS), nitric oxide (NO), and prostaglandin E2 (PGE2) productions, and reduced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions via NF-κB nuclear translocation, in RAW 264.7 cells. It also reduced chemokines (TARC/CCL17, RANTES/CCL5, MCP-1/CCL2, and IL-8) and the cytokine IL-1β production in HaCaT cells, suggesting potential as a therapeutic candidate for chronic diseases like atopic dermatitis. Finally, in silico studies indicated palmitic acid as a significant contributor to the observed effect. This research not only uncovered the untapped potential of C. linum but also laid the foundation for its integration into the circular bioeconomy, promoting sustainable practices, and innovative applications across various industries.

(+)-Borneol Protects Dopaminergic Neuronal Loss in Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-Induced Parkinson's Disease Mice: A Study of Dopamine Level using In Vivo Brain Microdialysis.

Considerable research efforts have been directed toward the symptom relief of Parkinson's disease (PD) by attenuating dopamine (DA) depletion. One common feature of these existing therapies is their unavailability of preventing the neurodegenerative process of dopaminergic neurons. (+)-Borneol, a natural highly lipid-soluble bicyclic monoterpene, has been reported to regulate the levels of monoamine neurotransmitters in the central nervous system and exhibit neuroprotective effects. However, the effect of (+)-borneol on the dopaminergic neuronal loss of methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice is not defined. Herein, we first report that 30 mg/kg (+)-borneol significantly attenuated the motor deficits of PD mice, which benefits from markedly increasing the level of DA and decreasing the metabolic rate of DA in the striatum of conscious and freely moving mouse detected by ultraperformance liquid chromatography tandem mass spectrometry online combined with in vivo brain microdialysis sampling. It is worth noting that the enhanced level of DA by (+)-borneol was enabled by the reduction in loss of tyrosine hydroxylase-immunoreactive dopaminergic neurons in the substantia nigra and striatum and promotion of reserpine- or nomifensine-induced DA release in PD mice. Interestingly, (+)-borneol evidently inhibited the decreased expression levels of DA transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) on the MPTP mouse model of PD. Moreover, (+)-borneol suppressed the neuroinflammation by inhibiting the production of IL-1β, IL-6, and TNF-α and attenuated oxidative stress by decreasing the level of MDA and increasing the activities of SOD and GSH-px in PD mice. These findings demonstrate that (+)-borneol protects DA neurons by inhibiting neuroinflammation and oxidative stress. Further research work for the neuroprotection mechanism of (+)-borneol will focus on reactive oxygen species-mediated apoptosis. Therefore, (+)-borneol is a potential therapeutic candidate for retarding the neurodegenerative process of PD.

Anti-inflammatory lindenane sesquiterpenoid dimers from the roots of Chloranthus holostegius var. trichoneurus.

Two new lindenane-type sesquiterpenoid dimers, chlotrichenes C and D (1 and 2) together with five known lindenane-type sesquiterpenoid dimers (3-7) were isolated from the roots of Chloranthus holostegius var. trichoneurus, a famous natural medicine named as "Sikuaiwa" for subduing swellings and relieving pain. The structures including absolute configuration were elucidated by their 1D and 2D NMR, HRESIMS, and ECD data. Compounds 1 and 2 were classical [4 + 2] lindenane-type sesquiterpenoid dimers that differed from known analogs in oxidation profile, side chain profile, and double bond position. The new isolates and compound 3 exhibited significant inhibitory activity on IL-1β production (IC50: 1-15μM) in LPS-induced THP-1 cells and other compounds exhibited inhibitory activity on NO production in LPS-induced RAW 264.7 cells (IC50: 24-33μM).

Cutaneous inflammasome driving ASC / gasdermin-D activation and IL-1β-secreting macrophages in severe atopic dermatitis.

Atopic dermatitis (AD) is an inflammatory skin disease with intense pruritus, and chronic skin colonization by Staphylococcus aureus. To understand the inflammatory status in AD, we investigated the inflammasome complex, that activates ASC (Apoptosis-associated speck-like protein containing a CARD), caspase-1 and GSDMD (gasdermin-D), and production of IL-1β and IL-18. We aimed to evaluate the expression of the inflammasome pathway in the skin of adults with AD. Thirty patients with moderate to severe AD and 20 healthy controls were enrolled in the study. We performed the analysis of the inflammasome components NLRP1, NLRP3, AIM-2, IL-1β, IL-18, Caspase-1, ASC, GSDMD, and CD68 expression (macrophage marker) by immunohistochemistry and immunofluorescence. The main findings included increased expression of NLRP3, NLRP1 and AIM-2 at dermal level of severe AD; augmented IL-18 and IL-1β expression at epidermis of moderate and severe patients, and in the dermis of severe AD; augmented expression of ASC, caspase-1 and GSDMD in both epidermis and dermis of moderate and severe AD. We detected positive correlation between caspase-1, GSDMD and IL-1β (epidermis) and caspase-1 (dermis) and AD severity; NLRP3, AIM-2 and IL-1β, and NLRP3 with IL-18 in the epidermis; ASC, GSDMD and IL-1β, and NLRP3, AIM-2, caspase-1, and IL-18 in the dermis. We also evidenced the presence of CD68+ macrophages secreting GSDMD, ASC and IL-1β in moderate and severe AD. Cutaneous macrophages, early detected in moderate AD, have its role in the disease inflammatory mechanisms. Our study indicates a canonical activation pathway of inflammasomes, reinforced by the chronic status of inflammation in AD. The analysis of the inflammasome complex evidenced an imbalance in its regulation, with increased expression of the evaluated components, which is remarkably in severe AD, emphasizing its relevance as potential disease biomarkers and targets for immunomodulatory interventions.

Lobetyolin protects mice against LPS-induced sepsis by downregulating the production of inflammatory cytokines in macrophage.

Introduction: Sepsis is a clinical syndrome characterized by dysregulation of the host immune response due to infection, resulting in life-threatening organ damage. Despite active promotion and implementation of early preventative measures and bundle treatments, sepsis continues to exhibit high morbidity and mortality rates with no optimal pharmacological intervention available. Lobetyolin (LBT), the crucial component of polyacetylenes found in Codonopsis pilosula, has been scientifically proven to possess potent antioxidant and antitumor properties. However, its therapeutic potential for sepsis remains unknown. Methods: The mice received pretreatment with intraperitoneal injections of LBT, followed by injection with lipopolysaccharide (LPS) to induce sepsis. Peripheral blood samples were collected to detect TNF-α, IL-1β, and IL-6 levels. The survival status of different groups was recorded at various time intervals. RNA-Seq was utilized for the analysis of gene expression in peritoneal macrophages treated with LBT or LPS. Results: In this study, we observed a significant increase in the survival rate of mice pretreated with LBT in LPS induced sepsis mouse model. LBT demonstrated a remarkable reduction in the production of IL-6, TNF-α, and IL-1β in the serum, along with mitigated lung and liver tissue damage characterized by reduced inflammatory cell infiltration. Additionally, through RNA-seq analysis coupled with GO and KEGG analysis, it was revealed that LBT effectively suppressed genes associated with bacterium presence, cellular response to lipopolysaccharide stimulation, as well as cytokine-cytokine receptor interaction involving Cxcl10, Tgtp1, Gbp5, Tnf, Il1b and IRF7 specifically within macrophages. We also confirmed that LBT significantly downregulates the expression of IL-6, TNF-α, and IL-1β in macrophage activation induced by LPS. Discussion: Therefore, our findings demonstrated that LBT effectively inhibits the production of inflammatory cytokines (IL-6, TNF-α, and IL-1β) and mitigates sepsis induced by LPS through modulating macrophages' ability to generate these cytokines. These results suggest that LBT holds promise as a potential therapeutic agent for sepsis treatment.

Impact of IL-1β on lung pathology caused by Mycobacterium abscessus infection and its association with IL-17 production

Mycobacterium abscessus (MAB), a non-tuberculous mycobacterium (NTM), causes chronic pulmonary inflammation in humans. The NLRP3 inflammasome is a multi-protein complex that triggers IL-1β maturation and pyroptosis through the cleavage of caspase-1. In this study, we investigated the roles of NLRP3 and IL-1β in the host's defense against MAB. The IL-1β production by MAB was completely abolished in NLRP3, but not NLRC4, deficient macrophages. The NLRP3 inflammasome components, which are ASC and caspase-1 were also found to be essential for IL-1β production in response to MAB. NLRP3 and IL-1β deficiency did not affect the intracellular growth of MAB in macrophages, and the bacterial burden in lungs of NLRP3- and IL-1β-deficient mice was also comparable to the burden observed in WT mice. In contrast, IL-1β deficiency ameliorated lung pathology in MAB-infected mice. Notably, the lung homogenates of IL-1β-deficient mice had reduced levels of IL-17, but not IFN-γ and IL-4 when compared with WT counterparts. Furthermore, in vitro co-culture analysis showed that IL-1β signaling was essential for IL-17 production in response to MAB. Finally, we observed that the anti-IL-17 antibody administration moderately mitigated MAB-induced lung pathology. These findings indicated that IL-1β production contribute to MAB-induced lung pathology via the elevation of IL-17 production.

Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis

BackgroundPsoriasis is an inflammatory skin disease characterized by the hyperproliferative epidermal keratinocytes and significant immune cells infiltration, leading to cytokines production such as IL-1β, TNF-α, IL-23, and IL-17. Recent study highlights the critical role of IL-1β in the induction and activation of pathogenic Th17 and IL-17-producing γδ T cells, contributing to psoriasis. However, the mechanism underlying IL-1β dysregulation in psoriasis pathogenesis is unclear. Autophagy regulates IL-1β production and has a pleiotropic effect on inflammatory disorders. Previous studies showed controversial role of autophagy in psoriasis pathogenesis, either pro-inflammatory in autophagy-deficient keratinocyte or anti-inflammatory in pharmacologically autophagy-promoting macrophages. Thus, the direct role of autophagy and its therapeutic potential in psoriasis remains unclear.MethodsWe used myeloid cell-specific autophagy-related gene 7 (Atg7)-deficient mice and determined the effect of autophagy deficiency in myeloid cells on neutrophilia and disease pathogenesis in an imiquimod-induced psoriasis mouse model. We then assessed the pathogenic mechanism focusing on immune cells producing IL-1β and IL-17 along with gene expression profiles associated with psoriasis in mouse model and public database on patients. Moreover, therapeutic potential of IL-1β blocking in such context was assessed.ResultsWe found that autophagy deficiency in myeloid cells exacerbated neutrophilic inflammation and disease pathogenesis in mice with psoriasis. This autophagy-dependent effect was associated with a significant increase in IL-1β production from myeloid cells, particularly macrophages, Cxcl2 expression, and IL-17 A producing T cells including γδ T cells. Supporting this, treatment with systemic IL-1 receptor blocking antibody or topical saccharin, a disaccharide suppressing pro-IL-1β expression, led to the alleviation of neutrophilia and psoriatic skin inflammation linked to autophagy deficiency. The pathophysiological relevance of this finding was supported by dysregulation of autophagy-related genes and their correlation with Th17 cytokines in psoriatic skin lesion from patients with psoriasis.ConclusionsOur results suggest that autophagy dysfunction in myeloid cells, especially macrophages, along with IL-1β dysregulation has a causal role in neutrophilic inflammation and psoriasis pathogenesis.

Anti-inflammatory activities of novel heat shock protein 90 isoform selective inhibitors in BV-2 microglial cells.

Heat shock protein 90 (Hsp90) is a family of chaperone proteins that consists of four isoforms: Hsp90α, Hsp90β, glucose-regulated protein 94 (Grp94), and tumor necrosis factor type 1 receptor-associated protein (TRAP1). They are involved in modulating the folding, maturation, and activation of their client proteins to regulate numerous intracellular signaling pathways. Previous studies demonstrated that pan-Hsp90 inhibitors reduce inflammatory signaling pathways resulting in a reduction of inflammation and pain but show toxicities in cancer-related clinical trials. Further, the role of Hsp90 isoforms in inflammation remains poorly understood. This study aimed to determine anti-inflammatory activities of Hsp90 isoforms selective inhibitors on the lipopolysaccharide (LPS)-induced inflammation in BV-2 cells, a murine microglial cell line. The production of inflammatory mediators such as nitric oxide (NO), interleukin 1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) was measured. We also investigated the impact of Hsp90 isoform inhibitors on the activation of nuclear factor kappa B (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and mitogen-activated protein kinases (MAPKs). We found that selective inhibitors of Hsp90β reduced the LPS-induced production of NO, IL-1β, and TNF-α via diminishing the activation of NF-κB and Extracellular signal-regulated kinases (ERK) MAPK. The Hsp90α, Grp94, TRAP1 inhibitors had limited effect on the production of inflammatory mediators. These findings suggest that Hsp90β is the key player in LPS-induced neuroinflammation. Thereby providing a more selective drug target for development of medications involved in pain management that can potentially contribute to the reduction of adverse side effects associated with Hsp90 pan inhibitors.

Coarse particulate matter (PM10) induce an inflammatory response through the NLRP3 activation

IntroductionPM exposure can induce inflammatory and oxidative responses; however, differences in these adverse effects have been reported depending on the chemical composition and size. Moreover, inflammatory mechanisms such as NLRP3 activation by PM10 have yet to be explored.ObjectiveTo assess the impact of PM10 on cell cytotoxicity and the inflammatory response through in vitro and in vivo models.MethodologyPeripheral blood mononuclear cells (PBMCs) from healthy donors were exposed to PM10. Cytotoxicity was determined using the LDH assay; the expression of inflammasome components and the production of pro-inflammatory cytokines were quantified through qPCR and ELISA, respectively; and the formation of ASC complexes was examined using confocal microscopy. For in vivo analysis, male C57BL6 mice were intranasally challenged with PM10 and bronchoalveolar lavage fluid was collected to determine cell counts and quantification of pro-inflammatory cytokines by ELISA. RNA was extracted from lung tissue, and the gene expression of inflammatory mediators was quantified.ResultsPM10 exposure induced significant cytotoxicity at concentrations over 100 µg/mL. Moreover, PM10 enhances the gene expression and release of pro-inflammatory cytokines in PBMCs, particularly IL-1β; and induces the formation of ASC complexes in a dose-dependent manner. In vivo, PM10 exposure led to cell recruitment to the lungs, which was characterized by a significant increase in polymorphonuclear cells compared to control animals. Furthermore, PM10 induces the expression of several inflammatory response-related genes, such as NLRP3, IL-1β and IL-18, within lung tissue.ConclusionBriefly, PM10 exposure reduced the viability of primary cells and triggered an inflammatory response, involving NLRP3 inflammasome activation and the subsequent production of IL-1β. Moreover, PM10 induces the recruitment of cells to the lung and the expression of multiple cytokines; this phenomenon could contribute to epithelial damage and, thus to the development and exacerbation of respiratory diseases such as viral infections.

Discovery of clinical candidate GS8-164, a highly potent oral NLRP3 inflammasome inhibitor for inflammation disorders

Abstract The NLRP3 inflammasome is a component of the innate immune system that plays a crucial role in the pathophysiology of multiple metabolic diseases. But so far, no marketed drugs specifically targeting NLRP3 have been approved. Here, we report the characterization of GS8-164, a potent and selective NLRP3 inflammasome inhibitor with a new phthalazine skeleton. In vitro, GS8-164 displayed potent inhibition of IL-1b production in THP-1, human PBMC and human whole blood assays without inhibiting either IL-6 or TNF-α. In vivo, GS8-164 strongly inhibited production of IL-1β in an acute mouse peritonitis model, and attenuated pathological progress and production of IL-1β in a rat acute pericarditis model. GS8-164 has a good ADME and toxicology profile. In 14-day rat and dog toxicology studies, GS8-164 displayed good tolerance, excellent PK profile and a good safety window (&amp;gt;50 fold). GS8-164 is under IND-enabling study and the clinical development is planned towards early 2025.

VIP deficiency disrupts immune ovarian homeostasis

Abstract Ovarian aging is associated with inflammation, contributing to the decline in oocyte count and quality. Since the vasoactive intestinal peptide (VIP) is an immunopeptide found in the reproductive tract with anti inflammatory effects inducing a tolerogenic response, we focus on VIP contribution to ovarian immune homeostasis preventing premature aging. We observed that young VIP KO mice (3 months old) display an altered ovarian histology with an increase in atretic follicles and less mature follicles as in aged WT mice (8 months old). This microenvironment was accompanied by an increased fibrosis deposition, ROS and IL-1β production. Interestingly, we found a significant decrease in ovarian reserve and the presence of foamy macrophages in young VIP KO ovary associated with premature aging. Getting insight into the mechanism involved in foam cell generation, we pre-conditioned young WT or VIP KO macrophages with WT or VIP KO ovarian media for 48h to mimic the ovarian microenvironment. Macrophages from VIP KO mice display a differential phagocytic ability of apoptotic bodies after preconditioning with WT or VIP KO ovarian media. However, only in VIP KO macrophages conditioned with VIP KO ovarian media we found an increase in lipid droplet accumulation, consistent with the formation of foamy macrophages. These findings highlight the role of VIP in regulating ovarian immune microenvironment, thereby preserving ovarian health and preventing premature aging.

Abstract 1116: IL-33 Promotes Cardiovascular Lesion Development In A Murine Model Of Kawasaki Disease By Boosting IL-1β Production

Kawasaki Disease (KD), a pediatric acute febrile systemic vasculitis, is the leading cause of acquired heart diseases in children. Coronary artery aneurysms (CAAs) occur in up to 25% of untreated children, which is reduced to 5% with intravenous immunoglobulin (IVIG) treatment. However, up to 20% of KD patients are refractory to IVIG and at higher risk of developing CAAs. This highlights the need to characterize the immune mechanisms mediating KD to develop more efficient therapies. IL-1β plays a key role in KD pathogenesis. IL-33, a member of the IL-1 cytokine family, is released upon inflammation and tissue damage and exerts its effects by binding to its receptor ST2 ( Il1rl1 ). Circulating levels of IL-33 are elevated in KD patients during the acute phase of the disease. However, if and how IL-33 contributes to cardiovascular lesion development in KD remains unknown. Using the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, we observed increased Il33 mRNA expression in hearts and abdominal aorta aneurysms of LCWE-injected mice. While ST2 was detected by immunofluorescence in the hearts of both control and LCWE-injected mice, its expression was increased in the abdominal aortas of LCWE-injected mice. In contrast, IL-33 expression was only increased in inflamed cardiovascular tissues of LCWE-injected mice. Single-cell RNA-sequencing and flow cytometric analysis of abdominal aortas, as well as spatial transcriptomics of heart tissues from LCWE-injected mice, indicated that Il33 transcripts were expressed primarily by stromal cells, such as fibroblasts, endothelial cells, and vascular smooth muscle cells. On the other hand, Il1rl1 transcripts were highly expressed by tissue infiltrating immune cells, such as macrophages, eosinophils, and neutrophils. Blocking IL-33, using either Il33 -/- mice or an anti-IL-33 antibody, significantly attenuated LCWE-induced KD vasculitis. In vitro, IL-33 treatment of LCWE-stimulated bone marrow-derived macrophages boosted their IL-1β production. Overall, our results indicate that IL-33, produced by stromal cells, may promote LCWE-induced KD vasculitis by increasing the release of IL-1β by tissue infiltrating immune cells, and this axis could therapeutically be targeted in KD.

Targeting the SIRT1 pathway to modulate inflammation in a murine model of Kawasaki Disease vasculitis

Abstract Kawasaki Disease (KD) is an acute febrile systemic vasculitis and the leading cause of acquired heart disease among children. Overactivation of the NLRP3 inflammasome and IL-1b production are critical for the development of cardiovascular lesions during KD. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase, is crucial for responding to cellular stress, and regulates NLRP3 activation as well as clearance of damaged mitochondria in cardiovascular diseases. However, its role in KD pathophysiology remains unknown. Here, we used the Lactobacillus casei cell wall extract (LCWE) murine model of KD to determine the role of SIRT1 on the development of cardiovascular lesions. We show that Sirt1 expression is downregulated in LCWE-injected mice with a significant reduction of nicotinamide, a product resulting from NAD+ degradation by SIRT1. In addition, supplementation of mice with NAD+ precursors significantly reduced the development of LCWE-induced cardiovascular lesions. Furthermore, KD development was less severe in SIRT1 overexpressing mice but was exacerbated with the specific deletion of Sirt1 in vascular smooth muscle cells. Treatment of LCWE-stimulated coronary smooth muscle cells with a SIRT1 activator favored mitophagy by inhibiting ribosomal S6 phosphorylation. These results indicate an impaired NAD+/SIRT1 axis during LCWE-induced KD vasculitis, which could potentially be targeted to reduce cardiovascular lesions in KD.

Antigen Presenting Cell activator protein 1 (AP-1) complex contributes to Salt-sensitive Blood Pressure

Salt-sensitivity of blood pressure (SSBP) affects 50% of the hypertensive and 25% of the normotensive population and is a major independent risk factor for cardiovascular morbidity and mortality. We previously found that SSBP is associated with activation of the NLRP3 inflammasome in antigen presenting cells (APCs) via increased oxidated stress and isolevuglandin (IsoLG) formation, but the underlying mechanisms are unknown. The activator protein 1 (AP-1) (FOS/JUN) has been implicated in activation of the NLRP3 inflammasome but its role in SSBP is not known. We hypothesized that AP-1 transcription factor in APCs senses elevated sodium and contributes to SSBP. We further hypothesize that antioxidant flavonoid, diosmetin prevents AP-1 activation and SSBP. Using bulk RNA-sequencing in human monocytes, we found elevated sodium increases expression of the AP-1 gene family when compared to normal sodium concentration, including cFOS (2378.18 ± 480.7 vs 6494.09 ± 945.55, p= 0.0009), FOSB (53.63 ± 17. 55 vs 131.06 ± 10.30, p= 0.397), cJUN (7313.90 ± 984.93 vs 11370.09 ± 1286.35, p= 0.2563) JUNB (4218.4.36 ± 199.17 vs 570.45 ± 200.91, p= 0.0445) and JUND (3309. 63 ± 270.64 vs 8057.90 ± 1043.05, p= 0.00006). In additional experiments, we enrolled people with hypertension and phenotype them for SSBP using an established in-patient protocol of salt-loading/depletion and performed single-cell transcriptomic analyses in vivo on peripheral blood mononuclear cells (PBMCs). We found that expression of the FOSB and JUNB genes are more sensitive in concert with blood pressure in salt-sensitive (SS) but not salt-resistant (SR) humans. Moreover, diosmetin attenuated high salt-induced hypertension, 123.5 ± 4.1 vs 146.8 ± 2.5 mm Hg in controls, **p&lt; 0.01). In addition, diosmetin also reduced high salt-induced inflammation including APC production of IsoLG-protein adducts, IL-1β, and NLRP3 inflammasome expression. These findings reveal a role for immune cell AP-1 (FOS/JUN) signaling in salt-sensitive hypertension and diosmetin may provide a potential therapeutic target for treatment of SSBP. 1R01HL144941-01A1. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.