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Background: Chicoric acid (CA) is a crucial immunologically active compound found in chicory and echinacea, possessing a range of biological activities. Ferroptosis, a type of iron-dependent cell death induced by lipid peroxidation, plays a key role in the development and advancement of asthma. Targeting ferroptosis could be a potential therapeutic strategy for treating asthma., Purpose: The purpose of this study was to explore the screening of ALOX15, a pivotal target of ferroptosis in asthma, and potential therapeutic agents, as well as to investigate the promising potential of CA as an ALOX15 inhibitor for modulating ferroptosis in asthma., Methods: Through high-throughput data processing of bronchial epithelial RNA from asthma patients using bioinformatics and machine learning, the key target of ferroptosis in asthma, ALOX15, was identified. An inhibitor of ALOX15 was then obtained through high-throughput molecular docking and molecular dynamics simulation tests. In vitro experiments were conducted using a 16HBE cell model induced by house dust mite (HDM) and lipopolysaccharide (LPS), which were treated with the ALOX15 inhibitor (PD146176), CA treatment, or ALOX15 knockdown. In vivo experiments were also carried out using a mouse model induced by HDM and LPS., Results: The composite model of ALOX15 and CA in molecular dynamics simulations shows good stability and flexibility. Network pharmacological analysis reveals that CA regulates ferroptosis through ALOX15 in treating asthma. In vitro studies show that ALOX15 is highly expressed in HDM and LPS treatments, while CA inhibits HDM and LPS-induced ferroptosis in 16HBE cells by reducing ALOX15 expression. Knockdown of ALOX15 has the opposite effect. Metabolomics analysis identifies key compounds associated with ferroptosis, including L-Targinine, eicosapentaenoic acid, 16-hydroxy hexadecanoic acid, and succinic acid. In vivo experiments demonstrate that CA suppresses ALOX15 expression, inhibits ferroptosis, and improves asthma symptoms in mice., Conclusion: Our research initially identified CA as a promising asthma treatment that effectively blocks ferroptosis by specifically targeting ALOX15. This study not only highlights CA as a potential therapeutic agent for asthma but also introduces novel targets and treatment options for this condition, along with innovative approaches for utilizing natural compounds to target diseases associated with ferroptosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Astrocytes, specialized glial cells, are essential for maintaining the central nervous system homeostasis. Inflammatory conditions can disrupt neurotrophic factors and receptor expression in astrocytes, leading to potential central nervous system damage. Itaconate, recently identified for its anti-inflammatory properties, was investigated in this study for its effects on neurotrophic factors in LPS-stimulated primary rat astrocytes., Methods: Primary rat astrocyte cells were isolated from one-day-old Wistar rats and exposed to 1 µg/ml lipopolysaccharide (LPS) for 6 h to stimulate inflammation. The effect of DMI (62.5, 125, and 250 µM for 18 h) on the cell viability of astrocyte cells exposed to LPS was evaluated by the MTT assay. The effects of DMI on the mRNA and protein levels of NGF, BDNF, and GDNF were evaluated using ELISA and qRT-PCR assays. Protein and mRNA levels of neurotrophic factor receptors (TrkA, TrkB, and P75) were evaluated using qRT-PCR and Western blot analyses., Results: The results showed that DMI suppressed astrocytes cell death induced by LPS in a dose-dependent manner. DMI dose-dependently restored the reduced mRNA and protein levels of NGF, BDNF, GDNF, and TrkA and TrkB receptors in LPS-treated astrocytes, but it significantly decreased the p75 expression in the same condition., Conclusion: In conclusion, DMI may be able to support astrocyte survival and functions based on the restoration of neurotrophic factors and their receptors expression in LPS-stimulated astrocyte cells. This suggests that DMI could be a promising therapeutic option for neurodegenerative diseases characterized by inflammation-induced astrocyte dysfunction.

Over the past decades, great efforts have been made to explore the glucopyranosyloxybenzyl succinates from Orchidaceae. At the same time, some of those compounds with new structures have led to new findings of their biological functions. The structures, classifications, distributions and bioactivities of glucopyranosyloxybenzyl succinates have been summarized in this review., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: The aim of this study was to investigate the mechanism of itaconate's potential effect in diabetic kidney disease., Methods: Renal immune responsive gene 1 (IRG1) levels were measured in db/db mice and streptozotocin (STZ) + high-fat diet (HFD)-induced diabetic mice. Irg1 knockout mice were generated. db/db mice were treated with 4-octyl itaconate (4-OI, 50 mg/kg), a derivative of itaconate, for 4 weeks. Renal function and morphological changes were investigated. Ultrastructural alterations were determined by transmission electron microscopy., Results: Renal IRG1 levels were reduced in two diabetic models. STZ+HFD-treated Irg1 knockout mice exhibited aggravated renal tubular injury and worsened renal function. Treatment with 4-OI lowered urinary albumin-to-creatinine ratio and blood urea nitrogen levels, and restored renal histological changes in db/db mice. It improved mitochondrial damage, increased expressions of peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α) and mitochondrial transcription factor A (TFAM) in the renal cortex of db/db mice. These were confirmed in vitro ; 4-OI improved high glucose-induced abnormal mitochondrial morphology and TFAM expression in HK-2 cells, effects that were inhibited by PGC-1α silencing. Moreover, 4-OI reduced the number of apoptotic cells in the renal cortex of db/db mice. Further study showed that 4-OI increased renal Nrf2 expression and decreased oxidative stress levels in db/db mice. In HK-2 cells, 4-OI decreased high glucose-induced mitochondrial ROS production, which was reversed by Nrf2 silencing. Nrf2 depletion also inhibited 4-OI-mediated regulation of PGC-1α, TFAM, and mitochondrial apoptotic protein expressions., Conclusions: 4-OI attenuates renal tubular injury in db/db mice by activating Nrf2 and promoting PGC-1α-mediated mitochondrial biogenesis.

Itaconate is produced as endogenous metabolite by decarboxylation of the citric acid cycle intermediate cis-aconitate. As itaconate has anti-microbial and anti-inflammatory properties, this substance is considered as potential therapeutic drug for the treatment of inflammation in various diseases including traumatic brain injury and stroke. To test for potential adverse effects of itaconate on the viability and metabolism of brain cells, we investigated whether itaconate or its membrane permeable derivatives dimethyl itaconate (DI) and 4-octyl itaconate (OI) may affect the basal glucose and glutathione (GSH) metabolism of cultured primary astrocytes. Acute exposure of astrocytes to itaconate, DI or OI in concentrations of up to 300 µM for up to 6 h did not compromise cell viability. Of the tested substances, only OI stimulated aerobic glycolysis as shown by a time- and concentration-dependent increase in glucose-consumption and lactate release. None of the tested itaconates affected the pentose-phosphate pathway-dependent reduction of the water-soluble tetrazolium salt 1 (WST1). In contrast, both DI and OI, but not itaconate, depleted cellular GSH in a time- and concentration-dependent manner. For OI this depletion was accompanied by a matching increase in the extracellular GSH content that was completely prevented in the presence of the multidrug resistance protein 1 (Mrp1)-inhibitor MK571, while in DI-treated cultures GSH was depleted both in cells and medium. These data suggest that OI stimulates Mrp1-mediated astrocytic GSH export, while DI reacts with GSH to a conjugate that is not detectable by the GSH assay applied. The data presented demonstrate that itaconate, DI and OI differ strongly in their effects on the GSH and glucose metabolism of cultured astrocytes. Such results should be considered in the context of the discussed potential use of such compounds as therapeutic agents., Competing Interests: Declarations Competing Interests The authors declare no competing interests., (© 2024. The Author(s).)

Objectives: Metabolic changes are crucially involved in osteoclast development and may contribute to bone degradation in rheumatoid arthritis (RA). The enzyme aconitate decarboxylase 1 (Acod1) is known to link the cellular function of monocyte-derived macrophages to their metabolic status. As osteoclasts derive from the monocyte lineage, we hypothesised a role for Acod1 and its metabolite itaconate in osteoclast differentiation and arthritis-associated bone loss., Methods: Itaconate levels were measured in human peripheral blood mononuclear cells (PBMCs) of patients with RA and healthy controls by mass spectrometry. Human and murine osteoclasts were treated with the itaconate derivative 4-octyl-itaconate (4-OI) in vitro. We examined the impact of Acod1-deficiency and 4-OI treatment on bone erosion in mice using K/BxN serum-induced arthritis and human TNF transgenic (hTNFtg) mice. SCENITH and extracellular flux analyses were used to evaluate the metabolic activity of osteoclasts and osteoclast progenitors. Acod1-dependent and itaconate-dependent changes in the osteoclast transcriptome were identified by RNA sequencing. CRISPR/Cas9 gene editing was used to investigate the role of hypoxia-inducible factor (Hif)-1α in Acod1-mediated regulation of osteoclast development., Results: Itaconate levels in PBMCs from patients with RA were inversely correlated with disease activity. Acod1-deficient mice exhibited increased osteoclast numbers and bone erosion in experimental arthritis while 4-OI treatment alleviated inflammatory bone loss in vivo and inhibited human and murine osteoclast differentiation in vitro. Mechanistically, Acod1 suppressed osteoclast differentiation by inhibiting succinate dehydrogenase-dependent production of reactive oxygen species and Hif1α-mediated induction of aerobic glycolysis., Conclusion: Acod1 and itaconate are crucial regulators of osteoclast differentiation and bone loss in inflammatory arthritis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Hypoxia-Induced Neonatal Seizure (HINS) is a prevalent type of seizure in infants caused by hypoxic conditions, which can lead to an increased risk of epilepsy, learning disabilities, and cognitive impairments later in life. This study focuses on examining the effects of dimethyl itaconate (DMI) on cognition, motor coordination, and anxiety-like behavior in male rats that have experienced HINS. 42 male Wistar newborn rats (PND10) were randomly divided into six groups (n = 7). 1) Control (Vehicle only); received DMI solvent (0.1ml) without applying hypoxia. 2-3) DMI; receiving (20 and 50 mg/kg; i.p). 4) HINS; they were placed in a hypoxia chamber with 7% oxygen and 93% nitrogen concentration for 15 minutes. 5-6) DMI+HINS; received DMI (20 and 50 mg/kg; i.p) 24h before hypoxia. Behavioral tests including; Novel object recognition test, Rotarod, Parallel bar, Open field and elevated plus maze (EPM); started at age 45 after birth. After behavioral tests, the hippocampal CA1 region local EEG was recorded in all groups. Then the brain hippocampus tissue was isolated and the amount of MDA, SOD, NO, and Thiol was measured by ELISA method. Data showed that the administration of DMI improved motor symptoms, anxiety-like behaviors, and cognition in HINS rats (p<0.05). EEG power in the HINS group decreased significantly compared to other experimental groups (p<0.05). Biochemical observations showed that DMI significantly reduced oxidative stress and inflammation in the hippocampal tissue of HINS rats (p<0.05). Increased hippocampal oxidative stress and inflammation can be effective in the occurrence of behavioral disorders observed in HINS rats. While DMI improved these behavioral impairments by reducing oxidative stress and inflammation., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Nazarizadeh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The Krebs cycle byproduct itaconate has recently emerged as an important metabolite regulating macrophage immune functions, but its role in tumor cells remains unknown. Here, we show that increased tumor-intrinsic cis-aconitate decarboxylase (ACOD1 or CAD, encoded by immune-responsive gene 1, Irg1) expression and itaconate production promote tumor immunogenicity and anti-tumor immune responses. Furthermore, we identify thimerosal, a vaccine preservative, as a specific inducer of IRG1 expression in tumor cells but not in macrophages, thereby enhancing tumor immunogenicity. Mechanistically, thimerosal induces itaconate production through a ROS-RIPK3-IRF1 signaling axis in tumor cells. Further, increased IRG1/itaconate upregulates antigen presentation-related gene expression via promoting TFEB nuclear translocation. Intratumoral injection of thimerosal induced itaconate production, activated the tumor immune microenvironment, and inhibited tumor growth in a T cell-dependent manner. Importantly, IRG1 deficiency markedly impaired tumor response to thimerosal treatment. Furthermore, itaconate induction by thimerosal potentiates the anti-tumor efficacy of adoptive T-cell therapy and anti-PD1 therapy in a mouse lymphoma model. Hence, our findings identify a new role for tumor intrinsic IRG1/itaconate in promoting tumor immunogenicity and provide a translational means to increase immunotherapy efficacy., Competing Interests: Disclosure and competing interests statement The authors declare no competing interests., (© 2024. The Author(s).)

Metabolic reprogramming drives inflammatory activity in macrophages, including microglia, with Krebs cycle (KC) intermediates playing a crucial role as signaling molecules. Here, we show that the bioenergetic profile of LPS-activated human microglialclone 3 cell line (HMC3) is characterized by high levels of glycolysis and mitochondrial (mt) respiration, and the treatment with KC derivatives, namely dimethyl-fumarate (DMF) and itaconate (ITA), almost restores normal metabolism. However, despite comparable bioenergetic and anti-inflammatory effects, the mt hyper-activity was differentially modulated by DMF and ITA. DMF normalized complex I activity, while ITA dampened both complex I and II hyper-activity counteracting oxidative stress more efficiently., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: Bone remodelling is a highly dynamic process dependent on the precise coordination of osteoblasts and haematopoietic-cell derived osteoclasts. Changes in core metabolic pathways during osteoclastogenesis, however, are largely unexplored and it is unknown whether and how these processes are involved in bone homeostasis., Methods: We metabolically and transcriptionally profiled cells during osteoclast and osteoblast generation. Individual gene expression was characterised by quantitative PCR and western blot. Osteoblast function was assessed by Alizarin red staining. immunoresponsive gene 1 ( Irg1 ) - deficient mice were used in various inflammatory or non-inflammatory models of bone loss. Tissue gene expression was analysed by RNA in situ hybridisation., Results: We show that during differentiation preosteoclasts rearrange their tricarboxylic acid cycle, a process crucially depending on both glucose and glutamine. This rearrangement is characterised by the induction of Irg1 and production of itaconate, which accumulates intracellularly and extracellularly. While the IRG1-itaconate axis is dispensable for osteoclast generation in vitro and in vivo, we demonstrate that itaconate stimulates osteoblasts by accelerating osteogenic differentiation in both human and murine cells. This enhanced osteogenic differentiation is accompanied by reduced proliferation and altered metabolism. Additionally, supplementation of itaconate increases bone formation by boosting osteoblast activity in mice. Conversely, Irg1- deficient mice exhibit decreased bone mass and have reduced osteoproliferative lesions in experimental arthritis., Conclusion: In summary, we identify itaconate, generated as a result of the metabolic rewiring during osteoclast differentiation, as a previously unrecognised regulator of osteoblasts., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Under high humidity and high temperature conditions, the quality of pepper essential oil easily deteriorates, and the oxidation of oil restricts its application, especially for the insolubility in water. This study investigated pepper essential oil encapsulated in Pickering emulsion with octenyl succinic acid starch, which was effectively able to reduce 100 times of the release rate. The smooth surface and complete particles of the emulsion were observed and no new chemical bonds were formed. The minimum particle sizes were 2.05 µm and 1.89 µm, when the Pickering emulsion was set to different storage conditions at pH 5 and 0.1 M NaCl, respectively. During gastrointestinal digestion, the release of essential oils was effectively delayed in the Pickering emulsion and the digestibility of the emulsion was 16.93% in 120 min. Compared with untreated cells, Pickering emulsion can effectively inhibit the proliferation of MCF-7 (52.71%). All these results indicate that OSA starch stabilized pepper essential oil can effectively increase solubility, improve stability, and expand the application range. Therefore, it can provide a theoretical basis for applications of pepper essential oil, especially for the functional drug application., (© 2024 Institute of Food Technologists.)

M pro , the main protease and a crucial enzyme in SARS-CoV-2 is the most fascinating molecular target for pharmacological treatment and is also liable for viral protein maturation. For antiviral therapy, no drugs have been approved clinically to date. Targeting the M pro with a compound having inhibitory properties against it can hinder viral replication. The therapeutic potential of the antiviral compound Nirmatrelvir (NMV) against SARS-CoV-2 M pro was investigated using a systematic approach of molecular docking, MD simulations, and binding free energy calculation based on the MM-GBSA method. NMV, a covalent inhibitor with a recently revealed chemical structure, is a promising oral antiviral clinical candidate with significant in vitro anti-SARS-CoV-2 action in third-phase clinical trials. To explore the therapeutic ability and possible drug resistance, the M pro system was studied for WT and two of its primary mutants (C145A & C145S). The protein-ligand (M pro /NMV) complexes were further examined through long MD simulations to check the possible drug resistance in the mutants. To understand the binding affinity, the MM-GBSA method was applied to the M pro /NMV complexes. Moreover, PCA analysis confirms the detachment of the linker region from the major domains in C145S and C145A mutants allowing for conformational alterations in the active-site region. Based on the predicted biological activities and binding affinities of NMV to WT and mutant (C145A & C145S) M pro , it can be stipulated that NMV may have conventional potency to act as an anti-viral agent against WT M pro , while the catalytic-dyad mutations may show substantial mutation-induced drug resistance.Communicated by Ramaswamy H. Sarma.

The search for medications that can effectively reduce alveolar bone loss following tooth extraction is of great interest. This study aimed to observe the roles of 4-octyl itaconate (4-OI) in RANKL-induced osteoclastogenesis of bone marrow macrophages (BMMs) in vitro. Mandibular second molars were extracted to evaluate whether 4-OI could alleviate alveolar bone loss. 4-OI inhibited RANKL-induced osteoclastogenesis and promoted Nrf2 expression in bone marrow macrophages in vitro. Positive Nrf2 expressions were observed in inflammatory cells and osteoclasts in vivo. Treatment with 4-octyl itaconate increased Nrf2 expression, resulting in reduced inflammatory infiltration and osteoclastic activity after tooth extraction. Furthermore, increased expression of OCN and enhanced-alveolar bone healing of extraction socket were observed in the 4-OI group compared to the control group. Our results suggested that 4-OI could serve as a promising pharmacologic candidate for alveolar ridge preservation by alleviating alveolar bone loss following tooth extraction in rats., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Polycystic ovary syndrome (PCOS) is the most common cause of anovulation and infertility in women. Inflammation and oxidative stress are considered to be the causes of ovarian dysfunction in PCOS. Dimethyl itaconate, as a macrophage-derived immunometabolite, has anti-inflammatory and antioxidative properties, but limited data are available about its effect on female reproductive dysfunctions. The present study aimed to determine the effects of dimethyl itaconate, a cell-permeable derivative of itaconate, on the histological changes, oxidative stress, and inflammation in the ovaries of PCOS rats. In this experimental study, 48 mature female Wistar rats (160-180 g) were randomly divided into the six groups including control, PCOS, PCOS+DMI, PCOS+ metformin, control DMI and control metformin. Following PCOS induction by using testosterone enanthate (1 mg/100 g/day for 35 days), the animals were treated with DMI (50 mg/kg) or metformin (300 mg/kg) for 30 days. At the end of the experimental period, the insulin resistance markers (serum insulin and glucose concentrations, and the homeostasis model assessment of basal insulin resistance (HOMA-IR), oxidative stress index (OSI), and inflammatory cytokines were measured. The process of Folliculogenesis was evaluated by histological examination of the ovary. The results showed that DMI improved insulin resistance and decreased TNF- and IL-1β levels and OSI in the ovarian tissue of rats following androgen-induced PCOS. It also improved steroidogenesis and Folliculogenesis by reducing cystic follicles and ovarian tissue structure. Results indicated that DMI may be a potential candidate to ameliorate PCOS adverse effects by reducing insulin resistance, inflammation, and oxidative stress and restoring ovarian Folliculogenesis., Competing Interests: Declaration of Competing Interest The authors report no conflict of interest., (Copyright © 2024. Published by Elsevier Ltd.)

This work aimed to fabricate a Cloisite 30B-incorporated carboxymethyl cellulose graft copolymer of acrylic acid and itaconic acid hydrogel (Hyd) via a free radical polymerization method for controlled release of Sunitinib malate anticancer drug. The synthesized samples were characterized by FTIR, XRD, TEM, and SEM-dot mapping analyses. The encapsulation efficiency of Hyd and Hyd/Cloisite 30B (6 wt%) was 81 and 93%, respectively, showing the effectiveness of Cloisite 30B in drug loading. An in vitro drug release study showed that drug release from all samples in a buffer solution with pH 7.4 was higher than in a buffer solution with pH 5.5. During 240 min, the cumulative drug release from Hyd/Cloisite 30B (94.97% at pH 7.4) is lower than Hyd (53.71% at pH 7.4). Also, drug-loaded Hyd/Cloisite 30B (6 wt%) demonstrated better antibacterial activity towards S. Aureus bacteria and E. Coli. High anticancer activity of Hyd/Cloisite 30B against MCF-7 human breast cancer cells was shown by the MTT assay, with a MCF-7 cell viability of 23.82 ± 1.23% after 72-hour incubation. Our results suggest that Hyd/Cloisite 30B could be used as a pH-controlled carrier to deliver anticancer Sunitinib malate., (© 2024. The Author(s).)

The immune response gene 1 (IRG1) and its metabolite itaconate are implicated in modulating inflammation and oxidative stress, with potential relevance to sepsis-induced myocardial dysfunction (SIMD). This study investigates their roles in SIMD using both in vivo and in vitro models. Mice were subjected to lipopolysaccharide (LPS)-induced sepsis, and cardiac function was assessed in IRG1 knockout (IRG1-/-) and wild-type mice. Exogenous 4-octyl itaconate (4-OI) supplementation was also examined for its protective effects. In vitro, bone marrow-derived macrophages and RAW264.7 cells were treated with 4-OI following Nuclear factor, erythroid 2 like 2 (NRF2)-small interfering RNA administration to elucidate the underlying mechanisms. Our results indicate that IRG1 deficiency exacerbates myocardial injury during sepsis, while 4-OI administration preserves cardiac function and reduces inflammation. Mechanistic insights reveal that 4-OI activates the NRF2/HO-1 pathway, promoting macrophage polarization and attenuating inflammation. These findings underscore the protective role of the IRG1/itaconate axis in SIMD and suggest a therapeutic potential for 4-OI in modulating macrophage responses., (© 2024. The Author(s).)

Itaconate serves as an immune-specific metabolite that regulates gene transcription and metabolism in both host and pathogens. S-itaconation is a post-translational modification that regulates immune response; however, its antimicrobial mechanism under the physiological condition remains unclear. Here, we apply a bioorthogonal itaconate probe to perform global profiling of S-itaconation in living pathogens, including S. Typhimurium, S. aureus, and P. aeruginosa. Some functional enzymes are covalently modified by itaconate, including those involved in the de novo purine biosynthesis pathway. Further biochemical studies demonstrate that itaconate suppresses this specific pathway to limit Salmonella growth by inhibiting the initiator purF to lower de novo purine biosynthesis and simultaneously targeting the guaABC cluster to block the salvage route. Our chemoproteomic study provides a global portrait of S-itaconation in multiple pathogens and offers a valuable resource for finding susceptible targets to combat drug-resistant pathogens in the future., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Itaconate is one of the most studied immunometabolites produced by myeloid cells during inflammatory response. It mediates a wide range of anti-inflammatory and immunoregulatory effects and plays a role in a number of pathological states, including autoimmunity and cancer. Itaconate and its derivatives are considered potential therapeutic agents for the treatment of inflammatory diseases. While immunoregulatory effects of itaconate have been extensively studied in vitro and using knockout mouse models, less is known about how therapeutic administration of this metabolite regulates inflammatory response in vivo. Here, we investigate the immunoregulatory properties of exogenous administration of itaconate and its derivative dimethyl itaconate in a mouse model of lipopolysaccharide-induced inflammation. The data show that administration of itaconate or dimethyl itaconate controls systemic production of multiple cytokines, including increased IL-10 production. However, only dimethyl itaconate was able to suppress systemic production of IFNγ and IL-1β. In contrast to in vitro data, administration of itaconate or dimethyl itaconate in vivo resulted in systemic upregulation of IL-6 in the blood. Electrophilic stress due to itaconate or dimethyl itaconate was not responsible for IL-6 upregulation. However, inhibition of succinate dehydrogenase with dimethyl malonate also resulted in elevated systemic levels of IL-6 and IL-10. Taken together, our study reports a novel effect of exogenous itaconate and its derivative dimethyl itaconate on the production of IL-6 in vivo, with important implications for the development of itaconate-based anti-inflammatory therapies., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology.)

The metabolite itaconate has emerged as an important immunoregulator with roles in antibacterial defence, inhibition of inflammation and, more recently, as an inhibitory factor in obesity. Itaconate is one of the most upregulated metabolites in inflammatory macrophages. It is produced owing to the disturbance of the tricarboxylic acid cycle and the diversion of aconitate to itaconate via the enzyme aconitate decarboxylase 1. In immunology, initial studies concentrated on the role of itaconate in inflammatory macrophages where it was shown to be inhibitory, but this has expanded as the impact of itaconate on other cell types is starting to emerge. This review focuses on itaconate as a key immunoregulatory metabolite and describes its diverse mechanisms of action and its many impacts on the immune and inflammatory responses and in cancer. We also examine the clinical relevance of this immunometabolite and its therapeutic potential for immune and inflammatory diseases., (© 2024. Springer Nature Limited.)

A wide variety of electrophilic derivatives of itaconate, the Kreb's cycle-derived metabolite, are immunomodulatory, yet these derivatives have overlapping and sometimes contradictory activities. Therefore, we generated a genetic system to interrogate the immunomodulatory functions of endogenously produced itaconate in human macrophages. Endogenous itaconate is driven by multiple innate signals restraining inflammatory cytokine production. Endogenous itaconate directly targets cysteine 13 in IRAK4 (disrupting IRAK4 autophosphorylation and activation), drives the degradation of nuclear factor κB, and modulates global ubiquitination patterns. As a result, cells unable to make itaconate overproduce inflammatory cytokines such as tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and IL-1β in response to these innate activators. In contrast, the production of interferon (IFN)β, downstream of LPS, requires the production of itaconate. These data demonstrate that itaconate is a critical arbiter of inflammatory cytokine production downstream of multiple innate signaling pathways, laying the groundwork for the development of itaconate mimetics for the treatment of autoimmunity., Competing Interests: Declaration of interests L.A.B., L.A.C., H.L., J.X., K.R., B.T., F.J.O., D.C.G., L.Z., Y.C.W., M.J.C., C.-W.Y., J.A.G., and F.C.D. are employees and shareholders of Eli Lilly and Company. L.A.J.O., M.S., and J.D.B. are employees or shareholders of Sitryx., (Copyright © 2024 Eli Lilly and Company. Published by Elsevier Inc. All rights reserved.)

Nasopharyngeal carcinoma (NPC) is a malignant tumor of epithelial origin in head and neck with high incidence rate in South China, Southeast Asia and North Africa. The intervention of tumor-associated macrophages (Mφs) (TAMs)-mediated immunosuppression is a potential therapeutic strategy against tumor metastasis, but the exact mechanisms of TAM-mediated immunosuppression in nasopharyngeal carcinoma are unclear. Furthermore, how TAM affects the occurrence and development of nasopharyngeal carcinoma through metabolism is rarely involved. In this work, we revealed that NPC cells promoted M2-type Mφ polarization and elevated itaconic acid (ITA) release. Also, TAMs facilitated NPC cell proliferation, migration, and invasion through immune response gene 1 (IRG1)-catalyzed ITA production. Then, IRG1-mediated ITA production in TAMs repressed the killing of CD8 + T cells, induced M2-type polarization of TAMs, and reduced the phagocytosis of TAMs. Moreover, we demonstrated ITA played a tumor immunosuppressive role by binding and dampening ten-eleven translocation-2 (TET2) expression. Finally, we proved that ITA promotes NPC growth by facilitating immune escape in CD34 + hematopoietic stem cell humanized mice. In Conclusion, TAM-derived ITA facilitated NPC progression by enhancing immune escape through targeting TET2, highlighting that interfering with the metabolic pathway of ITA may be a potential strategy for NPC treatment., (© 2024. The Author(s).)

The role of oxidative stress and ferroptosis in osteoarthritis (OA) pathogenesis is increasingly recognized. Notably, 4-octyl Itaconate (OI) has been documented to counteract oxidative stress and inflammatory responses, highlighting its therapeutic potential in OA. This study explored the effects of OI on GPX4 methylation, oxidative stress, and ferroptosis in chondrocytes affected by OA. Our results demonstrated that OI mitigated IL-1β-induced chondrocyte degeneration in a dose-dependent manner. It also suppressed reactive oxygen species (ROS) production and sustained GPX4 expression, thereby attenuating the degenerative impact of IL-1β and Erastin on chondrocytes by curtailing ferroptosis. Moreover, we observed that blocking GPX4 methylation could alleviate IL-1β-induced degeneration, oxidative stress, and ferroptosis in chondrocytes. The regulatory mechanism of OI on GPX4 expression in chondrocytes involved the inhibition of GPX4 methylation. In a mouse model of OA, OI's protective effects against OA were comparable to those of Ferrostatin-1. Thus, OI reduced chondrocyte degeneration, oxidative stress, and ferroptosis by inhibiting GPX4 methylation, offering a novel mechanistic insight into its therapeutic application in OA., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Despite advances in antimicrobial and anti-inflammatory treatment, inflammation and its consequences remain a major challenge in the field of medicine. Inflammatory reactions can lead to life-threatening conditions such as septic shock, while chronic inflammation has the potential to worsen the condition of body tissues and ultimately lead to significant impairment of their functionality. Although the central nervous system has long been considered immune privileged to peripheral immune responses, recent research has shown that strong immune responses in the periphery also affect the brain, leading to reactive microglia, which belong to the innate immune system and reside in the brain, and neuroinflammation. The inflammatory response is primarily a protective mechanism to defend against pathogens and tissue damage. However, excessive and chronic inflammation can have negative effects on neuronal structure and function. Neuroinflammation underlies the pathogenesis of many neurological and neurodegenerative diseases and can accelerate their progression. Consequently, targeting inflammatory signaling pathways offers potential therapeutic strategies for various neuropathological conditions, particularly Parkinson's and Alzheimer's disease, by curbing inflammation. Here the blood-brain barrier is a major hurdle for potential therapeutic strategies, therefore it would be highly advantageous to foster and utilize brain innate anti-inflammatory mechanisms. The tricarboxylic acid cycle-derived metabolite itaconate is highly upregulated in activated macrophages and has been shown to act as an immunomodulator with anti-inflammatory and antimicrobial functions. Mesaconate, an isomer of itaconate, similarly reduces the inflammatory response in macrophages. Nevertheless, most studies have focused on its esterified forms and its peripheral effects, while its influence on the CNS remained largely unexplored. Therefore, this study investigated the immunomodulatory and therapeutic potential of endogenously synthesized itaconate and its isomer mesaconate in lipopolysaccharide (LPS)-induced neuroinflammatory processes. Our results show that both itaconate and mesaconate reduce LPS-induced neuroinflammation, as evidenced by lower levels of inflammatory mediators, reduced microglial reactivity and a rescue of synaptic plasticity, the cellular correlate of learning and memory processes in the brain. Overall, this study emphasizes that both itaconate and mesaconate have therapeutic potential for neuroinflammatory processes in the brain and are of remarkable importance due to their endogenous origin and production, which usually leads to high tolerance., (© 2024. The Author(s).)

The Krebs cycle enzyme aconitate decarboxylase 1 (ACOD1) mediates itaconate synthesis in monocytes and macrophages. Previously, we reported that administration of 4-octyl itaconate to lupus-prone mice abrogated immune dysregulation and clinical features. In this study, we explore the role of the endogenous ACOD1/itaconate pathway in the development of TLR7-induced lupus (imiquimod [IMQ] model). We found that, in vitro, ACOD1 was induced in mouse bone marrow-derived macrophages and human monocyte-derived macrophages following TLR7 stimulation. This induction was partially dependent on type I IFN receptor signaling and on specific intracellular pathways. In the IMQ-induced mouse model of lupus, ACOD1 knockout (Acod1-/-) displayed disruptions of the splenic architecture, increased serum levels of anti-dsDNA and proinflammatory cytokines, and enhanced kidney immune complex deposition and proteinuria, when compared with the IMQ-treated wild-type mice. Consistent with these results, Acod1-/- bone marrow-derived macrophages treated in vitro with IMQ showed higher proinflammatory features. Furthermore, itaconate serum levels in systemic lupus erythematosus patients were decreased compared with healthy individuals, in association with disease activity and specific perturbed cardiometabolic parameters. These findings suggest that the ACOD1/itaconate pathway plays important immunomodulatory and vasculoprotective roles in systemic lupus erythematosus, supporting the potential therapeutic role of itaconate analogs in autoimmune diseases.

Itaconic acid and its derivative 4-octyl itaconate (OI) represent a novel anti-inflammatory medication that has demonstrated efficacy in multiple inflammation models because of its minimal side effects. Recently, natural polymers conjugated with small molecule drugs, known as polymer-drug conjugates (PDCs), have emerged as a promising approach to sustained drug release. In this work, we reported an approach to prepare a PDC containing an OI and make it into an injectable hydrogel. Chitosan (CS) was selected for PDC synthesis because of its abundant free amino groups that can be conjugated with molecules containing carboxyl groups by carbodiimide chemistry. We used an ethanol/water cosolvent system to synthesize a CS-OI conjugate via EDC/NHS catalysis. The CS-OI conjugate had improved water solubility and unique anti-inflammatory activity and did not show compromised antibacterial activity compared with unmodified CS. Beta-glycerophosphate (β-GP) cross-linked CS-OI hydrogel exhibited good injectability with sustainable OI release and effectively modulated inflammatory response in a rat model. Therefore, this study provides valuable insights into the design of PDC hydrogels with inflammatory modulatory properties.

Cichoric acid (CA), a widely utilized polyphenolic compound in medicine, has garnered significant attention due to its potential health benefits. Sepsis-induced acute kidney disease (AKI) is related with an elevated risk of end-stage kidney disease (ESKD). However, it remains unclear whether CA provides protection against septic AKI. The aim of this study is to investigated the protective effect and possible mechanisms of CA against LPS-induced septic AKI. Sepsis-induced AKI was induced in mice through intraperitoneal injection of lipopolysaccharide (LPS), and RAW264.7 macrophages were incubated with LPS. LPS exposure significantly increased the levels of M1 macrophage biomarkers while reducing the levels of M2 macrophage indicators. This was accompanied by the release of inflammatory factors, superoxide anion production, mitochondrial dysfunction, activation of succinate dehydrogenase (SDH), and subsequent succinate formation. Conversely, pretreatment with CA mitigated these abnormalities. CA attenuated hypoxia-inducible factor-1α (HIF-1α)-induced glycolysis by lifting the NAD + /NADH ratio in macrophages. Additionally, CA disrupted the K (lysine) acetyltransferase 2A (KAT2A)/α-tubulin complex, thereby reducing α-tubulin acetylation and subsequently inactivating the NLRP3 inflammasome. Importantly, administration of CA ameliorated LPS-induced renal pathological damage, apoptosis, inflammation, oxidative stress, and disturbances in mitochondrial function in mice. Overall, CA restrained HIF-1α-mediated glycolysis via inactivation of SDH, leading to NLRP3 inflammasome inactivation and the amelioration of sepsis-induced AKI., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aconitate decarboxylase-1 (ACOD1) is expressed by activated macrophages and generates itaconate that exerts anti-microbial and immunoregulatory effects. ACOD1-itaconate is essential for macrophage-mediated control of the intracellular pathogen Coxiella (C.) burnetii , which causes Q fever. Two isomers of itaconate, mesaconate and citraconate, have overlapping yet distinct activity on macrophage metabolism and inflammatory gene expression. Here, we found that all three isomers inhibited the growth of C. burnetii in axenic culture in ACCM-2 medium. However, only itaconate reduced C. burnetii replication efficiently in Acod1 -/- macrophages. In contrast, addition of citraconate strongly increased C. burnetii replication in Acod1 +/- macrophages, whereas mesaconate weakly enhanced bacterial burden in Acod1 -/- macrophages. Analysis of intracellular isomers showed that exogenous citraconate and mesaconate inhibited the generation of itaconate by infected Acod1 +/- macrophages. Uptake of added isomers into Acod1 -/- macrophages was increased after infection for itaconate and mesaconate, but not for citraconate. Mesaconate, but not citraconate, competed with itaconate for uptake into macrophages. Taken together, inhibition of itaconate generation by macrophages and interference with the uptake of extracellular itaconate could be identified as potential mechanisms behind the divergent effects of citraconate and mesaconate on C. burnetii replication in macrophages or in axenic culture., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Siddique, Kellermeier, Ölke, Zhao, Büssow, Oefner, Lührmann, Dettmer and Lang.)

Almost 16 % of the global population is affected by neurological disorders, including neurodegenerative and cerebral neuroimmune diseases, triggered by acute or chronic inflammation. Neuroinflammation is recognized as a common pathogenic mechanism in a wide array of neurological conditions including Alzheimer's disease, Parkinson's disease, postoperative cognitive dysfunction, stroke, traumatic brain injury, and multiple sclerosis. Inflammatory process in the central nervous system (CNS) can lead to neuronal damage and neuronal apoptosis, consequently exacerbating these diseases. Itaconate, an immunomodulatory metabolite from the tricarboxylic acid cycle, suppresses neuroinflammation and modulates the CNS immune response. Emerging human studies suggest that itaconate levels in plasma and cerebrospinal fluid may serve as biomarkers associated with inflammatory responses in neurological disorders. Preclinical studies have shown that itaconate and its highly cell-permeable derivatives are promising candidates for preventing and treating neuroinflammation-related neurological disorders. The underlying mechanism may involve the regulation of immune cells in the CNS and neuroinflammation-related signaling pathways and molecules including Nrf2/KEAP1 signaling pathway, reactive oxygen species, and NLRP3 inflammasome. Here, we introduce the metabolism and function of itaconate and the synthesis and development of its derivatives. We summarize the potential impact and therapeutic potential of itaconate and its derivatives on brain immune cells and the associated signaling pathways and molecules, based on preclinical evidence via various neurological disorder models. We also discuss the challenges and potential solutions for clinical translation to promote further research on itaconate and its derivatives for neuroinflammation-related neurological disorders., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

HIV-associated neurological disorder (HAND) is a serious complication of HIV infection marked by neurotoxicity induced by viral proteins like Tat. Substance abuse exacerbates neurocognitive impairment in people living with HIV. There is an urgent need for therapeutic strategies to combat HAND comorbid with Cocaine Use Disorder (CUD). Our analysis of HIV and cocaine-induced transcriptomes in primary cortical cultures revealed significant overexpression of the macrophage-specific gene aconitate decarboxylase 1 (Acod1). The ACOD1 protein converts the tricarboxylic acid intermediate cis-aconitate into itaconate during the activation of inflammation. Itaconate then facilitates cytokine production and activates anti-inflammatory transcription factors, shielding macrophages from infection-induced cell death. However, the immunometabolic function of itaconate was unexplored in HIV and cocaine-exposed microglia. We assessed the potential of 4-octyl-itaconate (4OI), a cell-penetrable ester form of itaconate known for its anti-inflammatory properties. When primary cortical cultures exposed to Tat and cocaine were treated with 4OI, microglial cell number increased and the morphological altercations induced by Tat and cocaine were reversed. Microglial cells also appeared more ramified, resembling the quiescent microglia. 4OI treatment inhibited secretion of the proinflammatory cytokines IL-1α, IL-1β, IL-6, and MIP1-α induced by Tat and cocaine. Transcriptome profiling determined that Nrf2 target genes were significantly activated in Tat and 4OI treated cultures relative to Tat alone. Further, genes associated with cytoskeleton dynamics in inflammatory microglia were downregulated by 4OI treatment. Together, the results strongly suggest 4-octyl-itaconate holds promise as a potential candidate for therapeutic development to treat HAND coupled with CUD comorbidities., (© 2024. The Author(s).)

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disease with a relapsing-remitting course. Although its etiology remains unknown, excessive oxidative stress in colon is a major intermediate factor that can promote the progression of UC. In the present study, we investigated the effect and the underlying mechanisms of 4-Octyl itaconate (OI) on dextran sulfate sodium (DSS)-induced UC in mice. Our work identified that OI alleviated the colitis by reducing the oxidative stress and the apoptosis in colon tissue, then increasing the tight junction proteins expression and in turn enhancing the intestinal barrier function, thereby creating less severe inflammatory responses. Moreover, our results demonstrated that OI reduced the Kelch-like ECH-associated protein 1 (KEAP1) expression and subsequent upregulated nuclear factor E2-related factor (NRF2) expression and its nuclear translocation which in turn induced the expression of glutathione S-transferase (GST) and NAD(P)H: quinone oxidoreductase 1 (NQO1). In addition, ML385, a NRF2 antagonist, can inhibit the protective effects of OI on UC, indicating that the role of OI in this colitis model could be dependent on the activation of KEAP1-NRF2 pathway. Notably, OI co-administration significantly enhanced the therapeutic effects of mesalazine or 1400W on UC. Collectively, itaconate may have a great potential for use in the treatment of IBD., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Neuronal ferroptosis plays a key role in neurologic deficits post intracerebral hemorrhage (ICH). However, the endogenous regulation of rescuing ferroptotic neurons is largely unexplored. Here, we analyzed the integrated alteration of metabolomic landscape after ICH using LC-MS and MALDI-TOF/TOF MS, and demonstrated that aconitate decarboxylase 1 (Irg1) and its product itaconate, a derivative of the tricarboxylic acid cycle, were protectively upregulated. Deficiency of Irg1 or depletion of neuronal Irg1 in striatal neurons was shown to exaggerate neuronal loss and behavioral dysfunction in an ICH mouse model using transgenic mice. Administration of 4-Octyl itaconate (4-OI), a cell-permeable itaconate derivative, and neuronal Irg1 overexpression protected neurons in vivo. In addition, itaconate inhibited ferroptosis in cortical neurons derived from mouse and human induced pluripotent stem cells in vitro. Mechanistically, we demonstrated that itaconate alkylated glutathione peroxidase 4 (GPx4) on its cysteine 66 and the modification allosterically enhanced GPx4's enzymatic activity by using a bioorthogonal probe, itaconate-alkyne (ITalk), and a GPx4 activity assay using phosphatidylcholine hydroperoxide. Altogether, our research suggested that Irg1/itaconate-GPx4 axis may be a future therapeutic strategy for protecting neurons from ferroptosis post ICH., (© 2024. The Author(s), under exclusive licence to ADMC Associazione Differenziamento e Morte Cellulare.)

Background: Quercetin has received extensive attention for its therapeutic potential treating respiratory syncytial virus (RSV) infection diseases. Recent studies have highlighted quercetin's ability of suppressing alveolar macrophages (AMs)-derived lung inflammation. However, the anti-inflammatory mechanism of quercetin against RSV infection still remains elusive., Purpose: This study aims to elucidate the mechanism about quercetin anti-inflammatory effect on RSV infection., Methods: BALB/c mice were intranasally infected with RSV and received quercetin (30, 60, 120 mg/kg/d) orally for 3 days. Additionally, an in vitro infection model utilizing mouse alveolar macrophages (MH-S cells) was employed to validate the proposed mechanism., Results: Quercetin exhibited a downregulatory effect on glycolysis and tricarboxylic acid (TCA) cycle metabolism in RSV-infected AMs. However, it increased itaconic acid production, a metabolite derived from citrate through activating immune responsive gene 1 (IRG1), and further inhibiting succinate dehydrogenase (SDH) activity. While the suppression of SDH activity orchestrated a cascading downregulation of Hif-1α/NLRP3 signaling, ultimately causing AMs polarization from M1 to M2 phenotypes., Conclusion: Our study demonstrated quercetin stimulated IRG1-mediated itaconic acid anabolism and further inhibited SDH/Hif-1α/NLRP3 signaling pathway, which led to M1 to M2 polarization of AMs so as to ameliorate RSV-induced lung inflammation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Nirmatrelvir, a pivotal component of the oral antiviral Paxlovid for COVID-19, targets the SARS-CoV-2 main protease (M pro ) as a covalent inhibitor. Here, we employed combined computational methods to explore how the prevalent Omicron variant mutation P132H, alone and in combination with A173V (P132H-A173V), affects nirmatrelvir's efficacy. Our findings suggest that P132H enhances the noncovalent binding affinity of M pro for nirmatrelvir, whereas P132H-A173V diminishes it. Although both mutants catalyze the rate-limiting step more efficiently than the wild-type (WT) M pro , P132H slows the overall rate of covalent bond formation, whereas P132H-A173V accelerates it. Comprehensive analysis of noncovalent and covalent contributions to the overall binding free energy of the covalent complex suggests that P132H likely enhances M pro sensitivity to nirmatrelvir, while P132H-A173V may confer resistance. Per-residue decompositions of the binding and activation free energies pinpoint key residues that significantly affect the binding affinity and reaction rates, revealing how the mutations modulate these effects. The mutation-induced conformational perturbations alter drug-protein local contact intensities and the electrostatic preorganization of the protein, affecting noncovalent binding affinity and the stability of key reaction states, respectively. Our findings inform the mechanisms of nirmatrelvir resistance and sensitivity, facilitating improved drug design and the detection of resistant strains.

Diabetes and derived complications, especially diabetic nephropathy and neuropathy annually cause great morbimortality worldwide. 5-hydroxytryptamine (5-HT) acts as a modulator of renal sympathetic input and vascular tone. In this line, 5-HT 2 receptor blockade has been linked with reduced incidence and progression of diabetic microvascular alterations. In this work, we aimed to determine, in diabetic rats, whether 5-HT 2 blockade ameliorates renal function and to characterize the serotonergic modulatory action on renal sympathetic neurotransmission. Diabetes was induced in male Wistar rats by alloxan administration (150 mg/kg, s.c.), and sarpogrelate (30 mg/kg·day, p.o.; 5-HT 2 antagonist) was administered for 14 days (DM-S). Normoglycemic and diabetic (DM) animals were maintained as aged-matched controls. At 28th day, DM-S animals were anesthetized and prepared for the in situ autoperfusion of the kidney. Renal vasoconstrictor responses were induced electrically or by i.a. noradrenaline (NA) administration. The role of 5-HT and selective 5-HT agonist/antagonist were studied on these renal vasopressor responses. Sarpogrelate treatment decreased renal sympathetic-induced vasopressor responses, reduced renal hypertrophy and kidney damage markers increased in DM. Intraarterial 5-HT inhibited the sympathetic-induced renal vasoconstrictions, effect reproduced by 5-CT, AS-19, L-694,247 and LY 344864 (5-HT 1/5/7 , 5-HT 7 , 5-HT 1D and 5-HT 1F receptor agonists, respectively). Blocking 5-HT 1D/1F/7 receptors completely abolished the 5-CT sympatho-inhibition. NA vasoconstrictions were not altered by any of the 5-HT agonists tested. Thus, in experimental diabetes, chronic sarpogrelate treatment reduces renal damage markers, kidney hypertrophy and renal sympathetic hyperactivity and modifies serotonergic modulation of renal sympathetic neurotransmission, causing a sympatho-inhibition by prejunctional 5-HT 1D/1F and 5-HT 7 activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Chicoric acid (CA) is a natural nutrient found in plants, showcasing diverse biological activities, including anti-inflammatory and antioxidant properties. Despite its valuable properties, CA faces limitations in bioavailability and susceptibility to oxidative breakdown during utilization. Previous research introduced synthesized dihydrocaffeic acid grafted chitosan self-assembled nanomicelles (DA-g-CS), demonstrating its potential to enhance CA absorption. This study aims to investigate the pharmacokinetics, tissue distribution, and antioxidant activity of both CA and DA-g-CS loaded CA (DA-g-CS/CA) in broilers. An IPEC-J2 cell model was established and evaluated to delve deeper into the transport mechanism and antioxidant potential. The in vivo pharmacokinetic analysis in broilers highlighted a substantial difference: the maximum plasma concentration (Cmax) of DA-g-CS/CA exceeded CA by 2.6-fold, yielding a notable increased relative bioavailability to 214%. This evidence underscores the significant enhancement in CA's oral absorption, facilitated by DA-g-CS. The collective evaluation outcomes affirm the successful development of the cell model, indicating its suitability for drug transporter experiments. The findings from the intestinal transit analysis revealed that both CA and DA-g-CS/CA underwent passive entry into IPEC-J2 cells. Notably, the cellular uptake rate of DA-g-CS loaded with CA was significantly amplified, reaching 2.1 times higher than that of CA alone. Intracellular transport mechanisms involved microtubules, lysosomes, and the endoplasmic reticulum, with an additional pathway involving the endoplasmic reticulum observed specifically for DA-g-CS/CA, distinguishing it from CA. Moreover, the results from both in vivo and in vitro antioxidant assessments highlight the potent antioxidant activity of DA-g-CS/CA, showcasing its efficacy in preventing and treating cellular damage induced by oxidative stress. In summary, these findings underscore the significant enhancement of CA's efficacy facilitated by DA-g-CS, establishing a robust theoretical foundation for the prospective application of CA within livestock and poultry farming., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Fibroblast-like synoviocytes (FLS) play critical roles in rheumatoid arthritis (RA). Itaconate (ITA), an endogenous metabolite derived from the tricarboxylic acid (TCA) cycle, has attracted attention because of its anti-inflammatory, antiviral, and antimicrobial effects. This study evaluated the effect of ITA on FLS and its potential to treat RA. ITA significantly decreased FLS proliferation and migration in vitro, as well as mitochondrial oxidative phosphorylation and glycolysis measured by an extracellular flux analyzer. ITA accumulates metabolites including succinate and citrate in the TCA cycle. In rats with type II collagen-induced arthritis (CIA), intra-articular injection of ITA reduced arthritis and bone erosion. Irg1-deficient mice lacking the ability to produce ITA had more severe arthritis than control mice in the collagen antibody-induced arthritis. ITA ameliorated CIA by inhibiting FLS proliferation and migration. Thus, ITA may be a novel therapeutic agent for RA., Competing Interests: Declaration of competing interest M. Kono has received research grants from GlaxoSmithKline, Mitsubishi Tanabe, Astellas, Sanofi, Taisho, Nippon Shinyaku, Taiju Life Social Welfare Foundation, Kowa, Terumo, Kyocera, Chugai, Mochida, Otsuka, Lotte, Hitachi, Takeda, and Yamazaki Baking, outside the submitted work. M. Kato received research grants and speaker's bureau from AbbVie, Janssen, Nippon Shinyaku, Novartis, Astellas, Eli Lilly, outside the submitted work. T. Atsumi has received grants, consulting fee or speakers' bureau from Astellas, Mitsubishi Tanabe, Chugai, Daiichi Sankyo, Pfizer, TEIJIN, Novartis, Sanofi, GlaxoSmithKline, AbbVie, AstraZeneca, Nippon Boehringer Ingelheim, Janssen, Gilead Sciences, Eli Lilly, ONO, Takeda, Alexion, Kyowa Kirin, Amgen, UCB Japan, and Esai, outside the submitted work. The other authors have no competing interests to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Neuromyelitis optica spectrum disorders (NMOSD) are rare inflammatory astrocytic diseases of the central nervous system (CNS). The roles of immune response gene-1 (IRG1) and the IRG1-itaconic acid-NLRP3 inflammatory pathway in the pathogenesis of NMOSD and the effects of 4-octyl itaconate (4-OI) on the NLRP3 inflammatory pathway in NMOSD are unclear. This study aimed to determine the role of IRG1 and the activation status of the NLRP3 inflammatory pathway in acute-onset NMOSD and to investigate the inhibitory effects of 4-OI on NLRP3 inflammasome activation via the IRG1-itaconic acid-NLRP3 pathway in monocytes and macrophages by using in vitro models., Methods: Peripheral blood mononuclear cells (PBMCs) and serum were collected from patients with acute NMOSDs and healthy controls (HC), followed by monocyte typing and detection of the expression of NLRP3-related inflammatory factors. Subsequently, the effects of 4-OI on the IRG1-itaconic acid-NLRP3 pathway were investigated in peripheral monocytes from patients with NMOSD and in macrophages induced by human myeloid leukemia mononuclear cells (THP-1 cells) via in vitro experiments., Results: Patients with acute NMOSD exhibited upregulated IRG1 expression. In particular, the upregulation of the expression of the NLRP3 inflammasome and proinflammatory factors was notable in monocytes in acute NMOSD patients. 4-OI inhibited the activation of the IRG1-itaconic acid-NLRP3 inflammatory pathway in the PBMCs of patients with NMOSD., Interpretation: 4-OI could effectively inhibit NLRP3 signaling, leading to the inhibition of proinflammatory cytokine production in patients with NMOSD-derived PBMCs and in a human macrophage model. Thus, 4-OI and itaconate could have important therapeutic value for the treatment of NMOSD in the future., (© 2024 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Sepsis, a systemic inflammatory response triggered by infection, has a considerably high mortality rate. However, effective prevention and intervention measures against sepsis remain insufficient. Therefore, this study aimed to investigate the mechanisms underlying the protective properties of immune response gene-1 (IRG1) and 4-Octyl itaconate (OI) during acute liver damage in mice with sepsis. A sepsis mouse model was established to compare wild-type and IRG1 -/- groups. The impact of IRG1/Itaconate on pro- and anti-inflammatory cytokines was evaluated using J774A.1 cells. IRG1/Itaconate substantially reduced pro-inflammatory cytokines and increased the release of anti-inflammatory cytokines. It reduced pathological damage to liver tissues, preserved normal liver function, decreased the release of reactive oxygen species (ROS) and LDH, and enhanced the GSH/GSSG ratio. Moreover, IRG1 and itaconic acid activated the Nrf2 signaling pathway, regulating the expression of its downstream antioxidative stress-related proteins. Additionally, they inhibited the activity of NLRP3 inflammatory vesicles to suppress the expression of macrophage-associated pyroptosis signaling molecules. Our findings demonstrate that IRG1/OI inhibits NLRP3 inflammatory vesicle activation and macrophage pyroptosis by modulating the Nrf2 signaling pathway, thereby attenuating acute liver injury in mice with sepsis. These findings could facilitate the clinical application of IRG1/Itaconate to prevent sepsis-induced acute liver injury., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Chichoric acid (CA) is a major active ingredient found in chicory and Echinacea. As a derivative of caffeic acid, it has various pharmacological effects., Purpose: Due to the unclear etiology and disease mechanisms, effective treatment methods for ulcerative colitis (UC) are currently lacking. The study investigated the therapeutic effects of the folate-chicory acid liposome on both LPS-induced macrophage inflammation models and dextran sulfate sodium (DSS)-induced mouse UC models., Methods: Folate-chicory acid liposome was prepared using the double emulsion ultrasonic method with the aim of targeting folate receptors specifically expressed on macrophages. The study investigated the therapeutic effects of the folate-chicory acid liposome on both LPS-induced macrophage inflammation models and DSS -induced mouse UC models. Furthermore, the effects of the liposomes on macrophage polarization and their underlying mechanisms in UC were explored., Results: The average particle size of folate-chicory acid liposome was 120.4 ± 0.46 nm, with an encapsulation efficiency of 77.32 ± 3.19 %. The folate-chicory acid liposome could alleviate macrophage apoptosis induced by LPS, decrease the expression of inflammatory factors in macrophages, enhance the expression of anti-inflammatory factors, inhibit macrophage polarization towards the M1 phenotype, and mitigate cellular inflammation in vetro. In vivo test, folate-chicory acid liposome could attenuate clinical symptoms, increased colon length, reduced DAI scores, CMDI scores, and alleviated the severity of colonic histopathological damage in UC mice. Furthermore, it inhibited the polarization of macrophages towards the M1 phenotype in the colon and downregulated the TLR4/NF-κB signaling pathway, thereby ameliorating UC in mice., Conclusion: Folate-chicory acid liposome exhibited a uniform particle size distribution and high encapsulation efficiency. It effectively treated UC mice by inhibiting the polarization of macrophages towards the M1 phenotype in the colon and downregulating the TLR4/NF-κB signaling pathway., Competing Interests: Declaration of competing interest There were no financial or commercial conflict of interest to declare., (Copyright © 2024. Published by Elsevier GmbH.)

4-octyl itaconate (4-OI) is an anti-inflammatory metabolite that activates the nuclear-factor-E2-related factor 2 (NRF2) signaling. In the current work, we investigated whether 4-OI could affect the production of proinflammatory cytokines in Behcet's uveitis (BU) and experimental autoimmune uveitis (EAU). Peripheral blood mononuclear cells (PBMCs) of active BU patients and healthy individuals with in vitro 4-OI treatment were performed to assess the influence of 4-OI on the proinflammatory cytokine production. EAU was induced and used for investigating the influence of 4-OI on the proinflammatory cytokine production in vivo. The flow cytometry, qPCR, and ELISA were performed to detect proinflammatory cytokine expression. NRF2 signaling activation was evaluated by qPCR and western blotting (WB). Splenic lymphocyte transcriptome was performed by RNA sequencing. The NRF2 expression by BU patients-derived PBMCs was lower than that by healthy individuals. After treatment with 4-OI, the proportion of Th17 cells, along with the expression of proinflammatory cytokines (IL-17, TNF-α, MCP-1, and IL-6) by PBMCs, were downregulated, and anti-inflammatory cytokine (IL-10) expression was upregulated, although IFN-γ expression was unaffected. The EAU severity was ameliorated by 4-OI in association with a lower splenic Th1/Th17 cell proportion and increased nuclear NRF2 expression. Additionally, 4-OI downregulated a set of 248 genes, which were enriched in pathways of positive regulation of immune responses. The present study shows an inhibitory effect of 4-OI on the proinflammatory cytokine production in active BU patients and EAU mice, possibly mediated through activating NRF2 signaling. These findings suggest that 4-OI could act as a potential therapeutic drug for the treatment and prevention of BU in the future study., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Premature infants often require oxygen supplementation, which can elicit bronchopulmonary dysplasia (BPD) and lead to mitochondrial dysfunction. Mitochondria play important roles in lung development, in both normal metabolism and apoptosis. Enhancing our comprehension of the underlying mechanisms in BPD development can facilitate the effective treatments., Methods: Plasma samples from BPD and non-BPD infants were collected at 36 weeks post-menstrual age and used for metabolomic analysis. Based on hyperoxia-induced animal and cell models, changes in mitophagy and apoptosis were evaluated following treatment with itaconic acid (ITA). Finally, the mechanism of action of ITA in lung development was comprehensively demonstrated through rescue strategies and administration of corresponding inhibitors., Results: An imbalance in the tricarboxylic acid (TCA) cycle significantly affected lung development, with ITA serving as a significant metabolic marker for the outcomes of lung development. ITA improved the morphological changes in BPD rats, promoted SP-C expression, and inhibited the degree of alveolar type II epithelial cells (AEC II) apoptosis. Mechanistically, ITA mainly promotes the nuclear translocation of transcription factor EB (TFEB) to facilitate dysfunctional mitochondrial clearance and reduces apoptosis in AEC II cells by regulating autophagic flux., Conclusion: The metabolic imbalance in the TCA cycle is closely related to lung development. ITA can improve lung development by regulating autophagic flux and promote the nuclear translocation of TFEB, implying its potential therapeutic utility in the treatment of BPD., Competing Interests: Declaration of competing interest The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Despite medical advances, there remains an unmet need for better treatment of obesity. Itaconate, a product of the decarboxylation of the tricarboxylic acid cycle intermediate cis-aconitate, plays a regulatory role in both metabolism and immunity. Here, we show that itaconate, as an endogenous compound, counteracts high-fat-diet (HFD)-induced obesity through leptin-independent mechanisms in three mouse models. Specifically, itaconate reduces weight gain, reverses hyperlipidemia, and improves glucose tolerance in HFD-fed mice. Additionally, itaconate enhances energy expenditure and the thermogenic capacity of brown adipose tissue (BAT). Unbiased proteomic analysis reveals that itaconate upregulates key proteins involved in fatty acid oxidation and represses the expression of lipogenic genes. Itaconate may provoke a major metabolic reprogramming by inducing fatty acid oxidation and suppression of fatty acid synthesis in BAT. These findings highlight itaconate as a potential activator of BAT-mediated thermogenesis and a promising candidate for anti-obesity therapy., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Mesotrione, as a widely used herbicide, is present in the environment in detectable amounts, causing serious damage. Here, we aimed to investigate the effect of mesotrione on Caco-2 cells and the possibility of its toxicity mitigation by cichoric acid. Therefore, we analyzed the cytotoxicity of both these compounds and the selected oxidative stress parameters, apoptosis and interaction of both the tested compounds with the cell membrane and their accumulation within the cells. In cytotoxicity studies, the stimulating activity of mesotrione was observed, and simultaneously, the inhibitory effect of cichoric acid was noticed. This effect was related to the results of oxidative stress analysis and apoptosis measurements. The activity level of key enzymes (glutathione peroxidase, catalase and superoxide dismutase) in Caco-2 cells exposed to cichoric acid was higher as compared to that of the control. The treatment with mesotrione did not induce apoptosis in the Caco-2 cells. The penetration of the studied compounds into the Caco-2 cells was measured by using an HPLC methodology, and the results indicate mesotrione's high penetration capacity. The distribution of charge on the surface of the cell membranes changed under the influence of both compounds. Considering the mutual interactions of beneficial and potentially toxic food ingredients, it should be noted that, despite the observed favorable trend, cichoric acid is not able to overcome the toxic and cancer-stimulating effects of this pesticide.

Background: Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the most common neurological problems occurring in the perinatal period. However, there still is not a promising approach to reduce long-term neurodevelopmental outcomes of HIE. Recently, itaconate has been found to exhibit anti-oxidative and anti-inflammatory effects. However, the therapeutic efficacy of itaconate in HIE remains inconclusive. Therefore, this study attempts to explore the pathophysiological mechanisms of oxidative stress and inflammatory responses in HIE as well as the potential therapeutic role of a derivative of itaconate, 4-octyl itaconate (4OI)., Methods: We used 7-day-old mice to induce hypoxic-ischemic (HI) model by right common carotid artery ligation followed by 1 h of hypoxia. Behavioral experiments including the Y-maze and novel object recognition test were performed on HI mice at P60 to evaluate long-term neurodevelopmental outcomes. We employed an approach combining non-targeted metabolomics with transcriptomics to screen alterations in metabolic profiles and gene expression in the hippocampal tissue of the mice at 8 h after hypoxia. Immunofluorescence staining and RT-PCR were used to evaluate the pathological changes in brain tissue cells and the expression of mRNA and proteins. 4OI was intraperitoneally injected into HI model mice to assess its anti-inflammatory and antioxidant effects. BV2 and C8D1A cells were cultured in vitro to study the effect of 4OI on the expression and nuclear translocation of Nrf2. We also used Nrf2-siRNA to further validate 4OI-induced Nrf2 pathway in astrocytes., Results: We found that in the acute phase of HI, there was an accumulation of pyruvate and lactate in the hippocampal tissue, accompanied by oxidative stress and pro-inflammatory, as well as increased expression of antioxidative stress and anti-inflammatory genes. Treatment of 4OI could inhibit activation and proliferation of microglial cells and astrocytes, reduce neuronal death and relieve cognitive dysfunction in HI mice. Furthermore, 4OI enhanced nuclear factor erythroid-2-related factor (Nfe2l2; Nrf2) expression and nuclear translocation in astrocytes, reduced pro-inflammatory cytokine production, and increased antioxidant enzyme expression., Conclusion: Our study demonstrates that 4OI has a potential therapeutic effect on neuronal damage and cognitive deficits in HIE, potentially through the modulation of inflammation and oxidative stress pathways by Nrf2 in astrocytes., (© 2024. The Author(s).)

The presence of heterogeneity in responses to oncolytic virotherapy poses a barrier to clinical effectiveness, as resistance to this treatment can occur through the inhibition of viral spread within the tumor, potentially leading to treatment failures. Here we show that 4-octyl itaconate (4-OI), a chemical derivative of the Krebs cycle-derived metabolite itaconate, enhances oncolytic virotherapy with VSVΔ51 in various models including human and murine resistant cancer cell lines, three-dimensional (3D) patient-derived colon tumoroids and organotypic brain tumor slices. Furthermore, 4-OI in combination with VSVΔ51 improves therapeutic outcomes in a resistant murine colon tumor model. Mechanistically, we find that 4-OI suppresses antiviral immunity in cancer cells through the modification of cysteine residues in MAVS and IKKβ independently of the NRF2/KEAP1 axis. We propose that the combination of a metabolite-derived drug with an oncolytic virus agent can greatly improve anticancer therapeutic outcomes by direct interference with the type I IFN and NF-κB-mediated antiviral responses., (© 2024. The Author(s).)

Background: Obesity is the main risk factor leading to the development of various respiratory diseases, such as asthma and pulmonary hypertension. Pulmonary microvascular endothelial cells (PMVECs) play a significant role in the development of lung diseases. Aconitate decarboxylase 1 (Acod1) mediates the production of itaconate, and Acod1/itaconate axis has been reported to play a protective role in multiple diseases. However, the roles of Acod1/itaconate axis in the PMVECs of obese mice are still unclear., Methods: mRNA-seq was performed to identify the differentially expressed genes (DEGs) between high-fat diet (HFD)-induced PMVECs and chow-fed PMVECs in mice (|log 2 fold change| ≥ 1, p ≤ 0.05). Free fatty acid (FFA) was used to induce cell injury, inflammation and mitochondrial oxidative stress in mouse PMVECs after transfection with the Acod1 overexpressed plasmid or 4-Octyl Itaconate (4-OI) administration. In addition, we investigated whether the nuclear factor erythroid 2-like 2 (Nrf2) pathway was involved in the effects of Acod1/itaconate in FFA-induced PMVECs., Results: Down-regulated Acod1 was identified in HFD mouse PMVECs by mRNA-seq. Acod1 expression was also reduced in FFA-treated PMVECs. Acod1 overexpression inhibited cell injury, inflammation and mitochondrial oxidative stress induced by FFA in mouse PMVECs. 4-OI administration showed the consistent results in FFA-treated mouse PMVECs. Moreover, silencing Nrf2 reversed the effects of Acod1 overexpression and 4-OI administration in FFA-treated PMVECs, indicating that Nrf2 activation was required for the protective effects of Acod1/itaconate., Conclusion: Our results demonstrated that Acod1/Itaconate axis might protect mouse PMVECs from FFA-induced injury, inflammation and mitochondrial oxidative stress via activating Nrf2 pathway. It was meaningful for the treatment of obesity-caused pulmonary microvascular endotheliopathy., (© 2024. The Author(s).)

Increasingly prevalent, nontuberculous mycobacteria (NTM) infections affect approximately 20% of people with cystic fibrosis (CF). Previous studies of CF sputum identified lower levels of the host metabolite itaconate in those infected with NTM. Itaconate can inhibit the growth of M. tuberculosis (MTB) in vitro via the inhibition of the glyoxylate cycle enzyme (ICL), but its impact on NTM is unclear. To test itaconic acid's (IA) effect on NTM growth, laboratory and CF clinical strains of Mycobacterium abscessus and Mycobacterium avium were cultured in 7H9 minimal media supplemented with 1-10 mM of IA and short-chain fatty acids (SCFA). M. avium and M. abscessus grew when supplemented with SCFAs, whereas the addition of IA (≥ 10 mM) completely inhibited NTM growth. NTM supplemented with acetate or propionate and 5 mM IA displayed slower growth than NTM cultured with SCFA and ≤ 1 mM of IA. However, IA's inhibition of NTM was pH dependent; as similar and higher quantities (100 mM) of pH adjusted IA (pH 7) did not inhibit growth in vitro, while in an acidic minimal media (pH 6.1), 1 to 5 mM of non-pH adjusted IA inhibited growth. None of the examined isolates displayed the ability to utilize IA as a carbon source, and IA added to M. abscessus isocitrate lyase (ICL) decreased enzymatic activity. Lastly, the addition of cell-permeable 4-octyl itaconate (4-OI) to THP-1 cells enhanced NTM clearance, demonstrating a potential role for IA/itaconate in host defense against NTM infections., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Breen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Corticosterone (CORT) damages hippocampal neurons as well as induces neuroinflammation. The tricarboxylic acid cycle metabolite itaconate has an anti-inflammatory role. Necroptosis is a form of programmed cell death, also known as inflammatory cell death. Menin is a multifunctional scaffold protein, which deficiency aggravates neuroinflammation. In this study, we explored whether itaconate inhibits CORT-induced neuroinflammation as well as necroptosis and further investigated the mediatory role of Menin in this protective effect of itaconate by using an exposure of CORT to HT22 cells (a hippocampal neuronal cell line). The viability of HT22 cells was examined by the cell counting kit 8 (CCK-8). The morphology of HT22 cells was observed by transmission electron microscope (TEM). The expressions of necroptosis-related proteins (p-RIP1/RIP1, p-RIP3/RIP3, and p-MLKL/MLKL) were evaluated by western blotting. The contents of inflammatory factors were detected by an enzyme-linked immunosorbent assay (ELISA) kit. Our results showed that CORT increases the contents of pro-inflammatory factors (IL-1β, TNF-α) as well as decreases the contents of anti-inflammatory factors (IL-4, IL-10) in HT22 cells. We also found that CORT increases the expressions of necroptosis-related proteins (p-RIP1/RIP1, p-RIP3/RIP3, and p-MLKL/MLKL) and decreases the cell viability in HT22 cells, indicating that CORT induces necroptosis in HT22 cells. Itaconate improves CORT-induced neuroinflammation and necroptosis. Furthermore, itaconate upregulates the expression of Menin in CORT-exposed HT22 cells. Importantly, silencing Menin abolishes the antagonistic effect of itaconate on CORT-induced necroptosis and neuroinflammation. In brief, these results indicated that itaconate protects HT22 cells against CORT-induced neuroinflammation and necroptosis via upregulating Menin., (© 2024. The Author(s) under exclusive licence to University of Navarra.)