TLR-driven early glycolytic reprogramming via the kinases TBK1-IKKɛ supports the anabolic demands of dendritic cell activation

Metabolism Serves as a Bridge Between Cardiomyocytes and Immune Cells in Cardiovascular Diseases

Metabolic disorders of cardiomyocytes play an important role in the progression of various cardiovascular diseases. Metabolic reprogramming can provide ATP to cardiomyocytes and protect them during diseases, but this transformation also leads to adverse consequences such as oxidative stress, mitochondrial dysfunction, and eventually aggravates myocardial injury. Moreover, abnormal accumulation of metabolites induced by metabolic reprogramming of cardiomyocytes alters the cardiac microenvironment and affects the metabolism of immune cells. Immunometabolism, as a research hotspot, is involved in regulating the phenotype and function of immune cells. After myocardial injury, both cardiac resident immune cells and heart-infiltrating immune cells significantly contribute to the inflammation, repair and remodeling of the heart. In addition, metabolites generated by the metabolic reprogramming of immune cells can further affect the microenvironment, thereby affecting the function of cardiomyocytes and other immune cells. Therefore, metabolic reprogramming and abnormal metabolite levels may serve as a bridge between cardiomyocytes and immune cells, leading to the development of cardiovascular diseases. Herein, we summarize the metabolic relationship between cardiomyocytes and immune cells in cardiovascular diseases, and the effect on cardiac injury, which could be therapeutic strategy for cardiovascular diseases, especially in drug research.

Extracellular vesicles from adipose-derived stromal/stem cells reprogram dendritic cells to alleviate rat TMJOA by transferring mitochondria

Temporomandibular joint osteoarthritis (TMJOA) urgently needs regenerative therapies due to the limited effects of traditional treatments. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are considered a potent alternative for MSC therapy for the treatment of TMJOA. However, the specific mechanisms remain inadequately investigated. In this study, we explored how EVs from adipose-derived stromal/stem cells (ASCs) influence the TMJOA model triggered by Complete Freund's Adjuvant in rats and their impact on the state of dendritic cells (DCs) under pathological conditions. Subsequently, we conducted transcriptomic and metabolomic analyses to elucidate the specific mechanisms by which EVs affect DCs. Mechanistically, we demonstrate that EVs transferred functional mitochondria to DCs, which reverses their metabolic states. The internalized functional mitochondria from EVs activate the MAPK/ERK1/2/FoxO1/autophagy pathway, which causes the metabolic reprogramming of DCs and facilitates the achievement of therapeutic effects. These findings provide a mechanistic rationale for utilizing ASCs-EVs as cell-free alternatives to MSC transplantation in TMJOA therapy.

Metformin ameliorates trophoblastic immunometabolic disorders via attenuating TLR4/NF-κB signaling through ATXN7L3-mediated histone H2B monoubiquitination

BACKGROUND

Trophoblastic inflammation and glycometabolic reprogramming represent two hallmarks of numerous diverse placental disorders, including but not limited to preterm labor, preeclampsia, and fetal growth restriction. Recent evidence indicates that TLR4/NF-κB signaling mediate the interaction between trophoblastic inflammation and glycometabolism disturbance while pharmacologic doses of metformin (MET, 10 μM) corrected these vicious states via its suppression on this pathway. However, the underlying precise mechanism remain incompletely understood.

METHODS

ATXN7L3 was identified through comprehensive proteomic screening. The oxidative phosphorylation and glycolysis were detected to evaluate the metabolic reprogramming. ELISA and adhesion experiment were used to evaluate the trophoblastic inflammation. Chromatin immunoprecipitation assay and co-immunoprecipitation assays were used to clarify the precise mechanism of MET on TLR4/NF-κB signaling.

RESULTS

MET corrected trophoblastic glycometabolic reprogramming and attenuated excessive inflammation via ATXN7L3. Mechanistically, MET regulated the TLR4/NF-κB signaling pathway through ATXN7L3-mediated Histone H2B monoubiquitylation.

CONCLUSIONS

Our findings elucidate a novel epigenetic regulatory mechanism whereby pharmacologic doses of MET ameliorated the TLR4/NF-κB signaling-induced immunometabolic disorders in trophoblasts through ATXN7L3-mediated H2Bub1. This study exploratively elucidated a novel mechanism underlying MET's pharmacological effects and provided novel insights into its role in ameliorating placental immunometabolism and development, potentially offering a novel pharmacological strategy for treating preeclampsia, fetal growth restriction, and related obstetrical syndromes.

TLR4 deficiency does not alter glaucomatous progression in a mouse model of chronic glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Toll-like receptor 4 (TLR4) is a pattern-recognition transmembrane receptor that induces neuroinflammatory processes in response to injury. Tlr4 is highly expressed in ocular tissues and is known to modulate inflammatory processes in both anterior and posterior segment tissues. TLR4 activation can lead to mitochondrial dysfunction and metabolic deficits in inflammatory disorders. Due to its effects on inflammation and metabolism, TLR4 is a candidate to participate in glaucoma pathogenesis. It has been suggested as a therapeutic target based on studies using acute models, such as experimentally raising IOP to ischemia-inducing levels. Nevertheless, its role in chronic glaucoma needs further evaluation. In the current study, we investigated the role of TLR4 in an inherited mouse model of chronic glaucoma, DBA/2J. To do this, we analyzed the effect of Tlr4 knockout (Tlr4-/-) on glaucoma in DBA/2J mice. Our studies found no significant differences in intraocular pressure, iris disease, or glaucomatous progression in Tlr4-/- compared to Tlr4+/+ DBA/2J mice. Our data do not support a role for TLR4 as a treatment target in chronic glaucoma.

UDP-glucose regulates dendritic cell mitochondrial respiration via a nitric oxide-dependent mechanism

Bone marrow-derived dendritic cell (BMDC) activation is associated with rewiring of cellular metabolism and concurrent large-scale changes in gene expression promoting a proinflammatory program characterized by expression of inducible nitric oxide synthase and the production of nitric oxide (NO). NO inhibits vital cellular activities including mitochondrial respiration. Mitochondrial respiration inhibition via NO occurs at discrete levels of activating stimulus, termed the mitochondrial respiration threshold, and regulation of this threshold is not fully understood. In this work, we characterize the role of uridine diphosphate glucose as a modulator of NO-mediated mitochondrial respiration inhibition via P2Y14 receptor signaling in stimulated BMDCs. We demonstrate that BMDCs exhibit an enhanced proinflammatory profile in the presence of uridine diphosphate glucose, providing evidence for a new NO regulatory axis in BMDCs. These studies highlight the importance of the growing body of literature supporting metabolites as signaling molecules in activating conditions thus allowing for better modeling of physiologically relevant contexts for myeloid cell encounters with microbial stimuli.

Immunometabolism of tumor-associated macrophages: A therapeutic perspective

Tumor-associated macrophages (TAMs) play a pivotal role in the tumor microenvironment (TME), actively contributing to the formation of an immunosuppressive niche that fosters tumor progression. Consequently, there has been a growing interest in targeting TAMs as a promising avenue for cancer therapy. Recent advances in the field of immunometabolism have shed light on the influence of metabolic adaptations on macrophage physiology in the context of cancer. Here, we discuss the key metabolic pathways that shape the phenotypic diversity of macrophages. We place special emphasis on how metabolic reprogramming impacts the activation status of TAMs and their functions within the TME. Additionally, we explore alterations in TAM metabolism and their effects on phagocytosis, production of cytokines/chemokines and interaction with cytotoxic T and NK immune cells. Moreover, we examine the application of nanomedical approaches to target TAMs and assess the clinical significance of modulating the metabolism of TAMs as a strategy to develop new anti-cancer therapies. Taken together, in this comprehensive review article focusing on TAMs, we provide invaluable insights for the development of effective immunotherapeutic strategies and the enhancement of clinical outcomes for cancer patients.

TLR5 Signaling Causes Dendritic Cell Dysfunction and Orchestrates Failure of Immune Checkpoint Therapy against Ovarian Cancer

Ovarian cancer accounts for more deaths than any other cancer of the female reproductive system. Patients who have ovarian tumors infiltrated with high frequencies of T cells are associated with a greater survival probability. However, therapies to revitalize tumor-associated T cells, such as PD-L1/PD-1 or CTLA4 blockade, are ineffective for the treatment of ovarian cancer. In this study, we demonstrate that for ovarian cancer, Toll-like receptor 5 (TLR5) signaling, for which the only known ligand is bacterial flagellin, governed failure of PD-L1 and CTLA4 blockade. Mechanistically, chronic TLR5 signaling on CD11c+ cells in vivo and in vitro impaired the differentiation of functional IL-12-producing XCR1+CD103+ conventional type 1 dendritic cells, biasing CD11c+ precursor cells toward myeloid subsets expressing high levels of PD-L1. This culminated in impaired activation of CD8+ T cells, reducing CD8+ T-cell function and ability to persist within the ovarian tumor microenvironment. Expansion of XCR1+CD103+ conventional type 1 dendritic cells in situ using Flt3L-Ig in combination with PD-L1 blockade achieved significant survival benefit in TLR5 knockout mice bearing ovarian tumors, whereas no benefit was observed in the presence of TLR5 signaling. Thus, we have identified a host-intrinsic mechanism leading to the failure of PD-L1 blockade for ovarian cancer, demonstrating that chronic TLR5 signaling on CD11c+ cells is a barrier limiting the efficacy of checkpoint therapy.

Integrating transcriptomics and metabolomics revealed pathogenic mechanism of Chinese soft-shell turtle (Trionyx sinensis) infected with Trionyx sinensis hemorrhagic syndrome virus (TSHSV)

Trionyx sinensis Hemorrhagic Syndrome Virus(TSHSV)seriously hinders the aquaculture of Chinese soft-shell turtle (Trionyx sinensis) due to its high mortality. However, the pathogenic mechanisms of TSHSV in T. sinensis are still unclear. In present study, transcriptomic and metabolomic analyses were performed on turtle livers following TSHSV infection. 734 up-regulated and 770 down-regulated differentially expressed genes (DEGs) were identified in different TSHSV challenge groups. These DEGs were categorized into 12 pathways related to virus infection and host immunity. Moreover, 27, 2679, and 4341 differentially expressed metabolites (DEMs) were identified in the D1, D3, and D5 groups, respectively. These DEMs were mapped into the pathways of energy metabolism, amino acid metabolism and fatty acid metabolism. Association analysis revealed TSHSV induced inflammatory responses, hepatocyte apoptosis, and ultimately led to liver tissue damage. Taurine supplementation promoted the survival rate of turtle after TSHSV infection and reduced the inflammatory response of liver by regulating the production of interferons, antioxidases, and the pro-inflammatory cytokine TNF-α. Collectively, our results provide comprehensive profiles of the transcriptome and metabolome in Chinese soft-shell turtle liver after TSHSV invasion, shedding light on the underlying pathogenic mechanism. The method of taurine supplementation might be a promising therapeutic strategy for protecting turtles from TSHSV.

The Emerging Mechanisms and Therapeutic Potentials of Dendritic Cells in NSCLC

Non-small-cell lung cancer (NSCLC) is the predominant subtype of lung cancer. Despite the demonstrated effectiveness of established treatments such as radiotherapy, chemotherapy, and immunotherapy, the prognosis for patients with advanced NSCLC remains poor. Dendritic cells (DCs), the most potent antigen-presenting cells (APCs), play a crucial role in the tumor microenvironment (TME) of NSCLC. This review explores the classification and biological functions of DCs, highlighting the specific molecular pathways and external factors that influence their maturation and function in NSCLC, which is novel in this review. Moreover, we discuss the potential therapeutic applications of DCs in the management of NSCLC, presenting novel possibilities for future treatments.

Influence of cell bioenergetics on host-pathogen interaction in the lung

Pulmonary diseases, arising from infections caused by bacteria, fungi, and viruses, or stemming from underlying genetic factors are one of the leading causes of mortality in humans, accounting for millions of deaths every year. At the onset of pulmonary diseases, crucial roles are played by phagocytic immune cells, particularly tissue-resident macrophages, in regulating the immune response at the mucosal barrier. Recent strides have illuminated the pivotal role of host bioenergetics modulated by metabolites derived from both pathogens and hosts in influencing the pathophysiology of major organs. Their influence extends to processes such as the infiltration of immune cells, activation of macrophages, and the polarization phenomenon. Furthermore, host-derived metabolites, such as itaconate, contribute to the promotion of anti-inflammatory responses, thereby preventing immunopathology and facilitating the preservation of mucosal niches to thrive for the long-term. This review explores recent advancements in the field of immunometabolism, with a particular emphasis on the intricacies of disease progression in pulmonary infections caused by bacteria such as P. aeruginosa, M. tuberculosis and S. aureus and fungi like C. albicans.

Mitochondrial hyperactivity and reactive oxygen species drive innate immunity to the yellow fever virus-17D live-attenuated vaccine

The yellow fever virus 17D (YFV-17D) live attenuated vaccine is considered one of the most successful vaccines ever generated associated with high antiviral immunity, yet the signaling mechanisms that drive the response in infected cells are not understood. Here, we provide a molecular understanding of how metabolic stress and innate immune responses are linked to drive type I IFN expression in response to YFV-17D infection. Comparison of YFV-17D replication with its parental virus, YFV-Asibi, and a related dengue virus revealed that IFN expression requires RIG-I-Like Receptor signaling through MAVS, as expected. However, YFV-17D uniquely induces mitochondrial respiration and major metabolic perturbations, including hyperactivation of electron transport to fuel ATP synthase. Mitochondrial hyperactivity generates reactive oxygen species (ROS) including peroxynitrite, blocking of which abrogated MAVS oligomerization and IFN expression in non-immune cells without reducing YFV-17D replication. Scavenging ROS in YFV-17D-infected human dendritic cells increased cell viability yet globally prevented expression of IFN signaling pathways. Thus, adaptation of YFV-17D for high growth imparts mitochondrial hyperactivity to meet energy demands, resulting in generation of ROS as the critical messengers that convert a blunted IFN response into maximal activation of innate immunity essential for vaccine effectiveness.

Dendritic cell maturation in cancer

Dendritic cells (DCs) are specialized antigen-presenting cells that are present at low abundance in the circulation and tissues; they serve as crucial immune sentinels by continually sampling their environment, migrating to secondary lymphoid organs and shaping adaptive immune responses through antigen presentation. Owing to their ability to orchestrate tolerogenic or immunogenic responses to a specific antigen, DCs have a pivotal role in antitumour immunity and the response to immune checkpoint blockade and other immunotherapeutic approaches. The multifaceted functions of DCs are acquired through a complex, multistage process called maturation. Although the role of inflammatory triggers in driving DC maturation was established decades ago, less is known about DC maturation in non-inflammatory contexts, such as during homeostasis and in cancer. The advent of single-cell technologies has enabled an unbiased, high-dimensional characterization of various DC states, including mature DCs. This approach has clarified the molecular programmes associated with DC maturation and also revealed how cancers exploit these pathways to subvert immune surveillance. In this Review, we discuss the mechanisms by which cancer disrupts DC maturation and highlight emerging therapeutic opportunities to modulate DC states. These insights could inform the development of DC-centric immunotherapies, expanding the arsenal of strategies to enhance antitumour immunity.

Unraveling the Complex Nexus of Macrophage Metabolism, Periodontitis, and Associated Comorbidities

BACKGROUND

Periodontitis is recognized as one of the most prevalent oral dysbiotic inflammatory diseases, ultimately leading to the irreversible destruction of periodontal tissues. Macrophages play a pivotal role in the development and progression of periodontitis, and the feasibility of targeting them therapeutically has been established. Since metabolic switching significantly contributes to macrophage regulation, conducting an in-depth review of macrophage metabolism in periodontitis may serve as the foundation for developing innovative treatments.

SUMMARY

This paper has been carefully reviewed to provide a comprehensive overview of the roles played by macrophages in periodontitis and associated comorbidities. Initially, detailed presentations on the metabolic reprogramming of macrophages, including glucose, lipid, and amino acid metabolism, were provided. Subsequently, dominating macrophage phenotype and metabolism under lipopolysaccharide (LPS) stimulation or during periodontitis were presented with emphasize on critical molecules involved. Furthermore, in recognition of the close association between periodontitis and several comorbidities, the interaction among macrophage metabolism, periodontitis, and related metabolic diseases, was thoroughly discussed.

KEY MESSAGES

Through the examination of current research on macrophage metabolic reprogramming induced by periodontitis, this review provides potential immunometabolic therapeutic targets for the future and raises many important, yet unstudied, subjects for follow-up.

BACKGROUND

Periodontitis is recognized as one of the most prevalent oral dysbiotic inflammatory diseases, ultimately leading to the irreversible destruction of periodontal tissues. Macrophages play a pivotal role in the development and progression of periodontitis, and the feasibility of targeting them therapeutically has been established. Since metabolic switching significantly contributes to macrophage regulation, conducting an in-depth review of macrophage metabolism in periodontitis may serve as the foundation for developing innovative treatments.

SUMMARY

This paper has been carefully reviewed to provide a comprehensive overview of the roles played by macrophages in periodontitis and associated comorbidities. Initially, detailed presentations on the metabolic reprogramming of macrophages, including glucose, lipid, and amino acid metabolism, were provided. Subsequently, dominating macrophage phenotype and metabolism under lipopolysaccharide (LPS) stimulation or during periodontitis were presented with emphasize on critical molecules involved. Furthermore, in recognition of the close association between periodontitis and several comorbidities, the interaction among macrophage metabolism, periodontitis, and related metabolic diseases, was thoroughly discussed.

KEY MESSAGES

Through the examination of current research on macrophage metabolic reprogramming induced by periodontitis, this review provides potential immunometabolic therapeutic targets for the future and raises many important, yet unstudied, subjects for follow-up.

TBK1 and IKKε prevent premature cell death by limiting the activity of both RIPK1 and NLRP3 death pathways

The loss of TBK1, or both TBK1 and the related kinase IKKε, results in uncontrolled cell death-driven inflammation. Here, we show that the pathway leading to cell death depends on the nature of the activating signal. Previous models suggest that in steady state, TBK1/IKKε-deficient cells die slowly and spontaneously predominantly by uncontrolled tumor necrosis factor-RIPK1-driven death. However, upon infection of cells that express the NLRP3 inflammasome, (e.g., macrophages), with pathogens that activate this pathway (e.g., Listeria monocytogenes), TBK1/IKKε-deficient cells die rapidly, prematurely, and exclusively by enhanced NLRP3-driven pyroptosis. Even infection with the RIPK1-activating pathogen, Yersinia pseudotuberculosis, results in enhanced RIPK1-caspase-8 activation and enhanced secondary NLRP3 activation. Mechanistically, TBK1/IKKε control endosomal traffic, and their loss disrupts endosomal homeostasis, thereby signaling cell stress. This results in premature NLRP3 activation even upon sensing "signal 2" alone, without the obligatory "signal 1." Collectively, TBK1/IKKε emerge as a central brake in limiting death-induced inflammation by both RIPK1 and NLRP3 death-inducing pathways.

Phthalates in face masks and their effects on cellular energetics in human bronchial epithelial cells

The widespread use of disposable masks has sparked concerns about potential exposure to harmful chemicals, including the already ubiquitous phthalates. It has been demonstrated that there is a causal relationship between the exposure to phthalates and the onset of respiratory diseases. Moreover, there is an increasing body of evidence, which suggests that mitochondria contribute to significant impact to the epithelial function in respiratory diseases. However, the specific effects induced by these compounds at the mitochondrial level in respiratory cells are unknown. The objective of this study was to identify phthalates in disposable face masks and to evaluate their effect on mitochondrial function in human bronchial epithelial cells (BEAS-2B). In order to identify and quantify the phthalates in face masks, an extraction method was developed and a phthalate quantification method using Gas Chromatography-Mass Spectrometry was employed. The analysis of the face masks sample revealed the presence of three major phthalates: di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and diisobutyl phthalate (DiBP). To evaluate the effects of these phthalates on mitochondrial function, BEAS-2B were exposed to the phthalates individually and in a mixture of the three at concentrations ranging from 0.5 to 10 mg/L for 24 hours. Then extracellular flux analysis (Seahorse analysis), adenosine levels (LC-DAD) and lactate levels (LC-MS) were evaluated. The observed effects at the mitochondrial level varied according to the specific phthalates that were tested. The major dysfunctions were identified following exposure to DEHP, which exerted inhibitory effects on the basal and maximal oxygen consumption rate of BEAS-2B cells, as well as an alteration in oxidative phosphorylation and a reduction in the ATP/ADP ratio. This was accompanied by an increase in both extracellular lactate production and extracellular acidification rate. A shift towards a glycolytic phenotype was noted. Similar, yet more pronounced effects, were observed following exposure to the mixture of the three phthalates, which suggest that DEHP may contribute to the overall effect of the mixture. This study is the first to provide knowledge on the adverse effects of a mixture of phthalates on mitochondrial function in bronchial epithelial cells, demonstrating the capacity of some phthalates to induce a shift toward a glycolytic phenotype. These results highlight the potential risks of inhaled phthalates on mitochondrial function, predisposing to the development of respiratory diseases.

Focus on mechano-immunology: new direction in cancer treatment

The immune response is modulated by a diverse array of signals within the tissue microenvironment, encompassing biochemical factors, mechanical forces, and pressures from adjacent tissues. Furthermore, the extracellular matrix and its constituents significantly influence the function of immune cells. In the case of carcinogenesis, changes in the biophysical properties of tissues can impact the mechanical signals received by immune cells, and these signals c1an be translated into biochemical signals through mechano-transduction pathways. These mechano-transduction pathways have a profound impact on cellular functions, influencing processes such as cell activation, metabolism, proliferation, and migration, etc. Tissue mechanics may undergo temporal changes during the process of carcinogenesis, offering the potential for novel dynamic levels of immune regulation. Here, we review advances in mechanoimmunology in malignancy studies, focusing on how mechanosignals modulate the behaviors of immune cells at the tissue level, thereby triggering an immune response that ultimately influences the development and progression of malignant tumors. Additionally, we have also focused on the development of mechano-immunoengineering systems, with the help of which could help to further understand the response of tumor cells or immune cells to alterations in the microenvironment and may provide new research directions for overcoming immunotherapeutic resistance of malignant tumors.

Recent advances in immunometabolism in rheumatic diseases

PURPOSE OF REVIEW

Aberrant autoreactive innate and adaptive immune responses cause systemic autoimmune diseases. Autoimmunity has been linked to abnormal metabolic states, and immunometabolism has emerged as a critical field in understanding the pathogenesis of rheumatic diseases. We aimed to explore the latest research on metabolic reprogramming in various immune cell types, including T cells, B cells, neutrophils, dendritic cells, monocytes, and macrophages, in the context of rheumatic diseases.

RECENT FINDINGS

Each immune cell utilizes preferred metabolic pathways, and the cell activation dramatically modifies metabolic status. The inhibition of these pathways alters cell survival, differentiation, proliferation, and cytokine production - all of which contribute to rheumatic disease progression.

SUMMARY

Targeting metabolic pathways or introducing anti-inflammatory metabolites, such as itaconate, could be novel therapeutic strategies for rheumatic diseases. Further research should focus on strategies for translating basic research findings to bedside applications.

Immunometabolic shifts in autoimmune disease: Mechanisms and pathophysiological implications

Autoimmune diseases occur when the immune system abnormally attacks the body's normal tissues, causing inflammation and damage. Each disease has unique immune and metabolic dysfunctions during pathogenesis. In rheumatoid arthritis (RA), immune cells have different metabolic patterns and mitochondrial/lysosomal dysfunctions at different disease stages. In systemic lupus erythematosus (SLE), type I interferon (IFN) causes immune cell metabolic dysregulation, linking activation to metabolic shifts that may worsen the disease. In systemic sclerosis (SSc), mitochondrial changes affect fibroblast metabolism and the immune response. Idiopathic inflammatory myopathies (IIMs) patients have mitochondrial and metabolic issues. In primary Sjögren's syndrome (pSS), immune cell metabolism is imbalanced and mitochondrial damage can lead to cell/tissue damage. Metabolic reprogramming links cellular energy needs and immune dysfunctions, causing inflammation, damage, and symptoms in these diseases. It also affects immune cell functions like differentiation, proliferation, and secretion. This review discusses the potential of targeting metabolic pathways to restore immune balance, offering directions for future autoimmune disease research and treatment.

TANK-Binding Kinase 1 in the Pathogenesis and Treatment of Inflammation-Related Diseases

TANK-binding kinase 1 (TBK1) is a key signaling kinase involved in innate immune and inflammatory responses. TBK1 drives immune cells to participate in the inflammatory response by activating the NF-κB and interferon regulatory factor signaling pathways in immune cells, promoting the expression of pro-inflammatory genes, and regulating immune cell function. Thus, it plays a crucial role in initiating a signaling cascade that establishes an inflammatory environment. In inflammation-related diseases, TBK1 acts as a bridge linking inflammation to immunity, metabolism, or tumorigenesis, playing an important role in the pathogenesis of immune-mediated inflammatory diseases, metabolic, inflammatory syndromes, and inflammation-associated cancers by regulating the activation of inflammatory pathways and the production of inflammatory cytokines in cells. In this review, we focused on the mechanisms of TBK1 in immune cells and inflammatory-related diseases, providing new insights for further studies targeting TBK1 as a potential treatment for inflammation-related diseases. Thus, optimizing and investigating highly selective cell-specific TBK1 inhibitors is important for their application in these diseases.

Renal mitochondria response to sepsis: a sequential biopsy evaluation of experimental porcine model

BACKGROUND

The pathophysiology of sepsis-induced acute kidney injury remains elusive. Although mitochondrial dysfunction is often perceived as the main culprit, data from preclinical models yielded conflicting results so far. The aim of this study was to assess the immune-metabolic background of sepsis-associated renal dysfunction using sequential biopsy approach with mitochondria function evaluation in a large clinically relevant porcine models mimicking two different paces and severity of sepsis and couple this approach with traditional parameters of renal physiology.

METHODS

In this randomized, open-label study, 15 anaesthetized, mechanically ventilated and instrumented (renal artery flow probe and renal vein catheter) pigs were randomized in two disease severity groups-low severity (LS) sepsis (0.5 g/kg of autologous faeces intraperitoneally) and high severity (HS) sepsis (1 g/kg of autologous faeces intraperitoneally). Sequential cortical biopsies of the left kidney were performed and a pyramid-shaped kidney specimen with cortex, medulla and renal papilla was resected and processed at the end of the experiment. Oxygraphic data and western blot analysis of proteins involved in mitochondrial biogenesis and degradation were obtained.

RESULTS

In contrast to increased mitochondrial activity observed in LS sepsis, a significant decrease in the oxidative phosphorylation capacity together with an increase in the respiratory system uncoupling was observed during the first 24 h after sepsis induction in the HS group. Those changes preceded alterations of renal haemodynamics. Furthermore, serum creatinine rose significantly during the first 24 h, indicating that renal dysfunction is not primarily driven by haemodynamic changes. Compared to cortex, renal medulla had significantly lower oxidative phosphorylation capacity and electron-transport system activity. PGC-1-alfa, a marker of mitochondrial biogenesis, was significantly decreased in HS group.

CONCLUSIONS

In this experimental model, unique sequential tissue data show that the nature and dynamics of renal mitochondrial responses to sepsis are profoundly determined by the severity of infectious challenge and resulting magnitude of inflammatory insult. High disease severity is associated with early and stepwise progression of mitochondria dysfunction and acute kidney injury, both occurring independently from later renal macro-haemodynamic alterations. Our data may help explain the conflicting results of preclinical studies and suggest that sepsis encompasses a very broad spectrum of sepsis-induced acute kidney injury endotypes.

Paroxetine alleviates dendritic cell and T lymphocyte activation via GRK2-mediated PI3K-AKT signaling in rheumatoid arthritis

BACKGROUND

G protein-coupled receptor kinase 2 (GRK2) could participate in the regulation of diverse cells via interacting with non-G-protein-coupled receptors. In the present work, we explored how paroxetine, a GRK2 inhibitor, modulates the differentiation and activation of immune cells in rheumatoid arthritis (RA).

METHODS

The blood samples of healthy individuals and RA patients were collected between July 2021 and March 2022 from the First Affiliated Hospital of Anhui Medical University. C57BL/6 mice were used to induce the collagen-induced arthritis (CIA) model. Flow cytometry analysis was used to characterize the differentiation and function of dendritic cells (DCs)/T cells. Co-immunoprecipitation was used to explore the specific molecular mechanism.

RESULTS

In patients with RA, high expression of GRK2 in peripheral blood lymphocytes, accompanied by the increases of phosphatidylinositol 3 kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR). In animal model, a decrease in regulatory T cells (T regs ), an increase in the cluster of differentiation 8 positive (CD8 + ) T cells, and maturation of DCs were observed. Paroxetine, when used in vitro and in CIA mice, restrained the maturation of DCs and the differentiation of CD8 + T cells, and induced the proportion of T regs . Paroxetine inhibited the secretion of pro-inflammatory cytokines, the expression of C-C motif chemokine receptor 7 in DCs and T cells. Simultaneously, paroxetine upregulated the expression of programmed death ligand 1, and anti-inflammatory cytokines. Additionally, paroxetine inhibited the PI3K-AKT-mTOR metabolic pathway in both DCs and T cells. This was associated with a reduction in mitochondrial membrane potential and changes in the utilization of glucose and lipids, particularly in DCs. Paroxetine reversed PI3K-AKT pathway activation induced by 740 Y-P (a PI3K agonist) through inhibiting the interaction between GRK2 and PI3K in DCs and T cells.

CONCLUSION

Paroxetine exerts an immunosuppressive effect by targeting GRK2, which subsequently inhibits the metabolism-related PI3K-AKT-mTOR pathway of DCs and T cells in RA.

Immunometabolic reprogramming in macrophages infected with active and dormant Cryptococcus neoformans: differential modulation of respiration, glycolysis, and fatty acid utilization

Dormancy is an adaptation in which cells reduce their metabolism, transcription, and translation to stay alive under stressful conditions, preserving the capacity to reactivate once the environment reverts to favorable conditions. Dormancy and reactivation of Cryptococcus neoformans (Cn) are closely linked to intracellular residency within macrophages. Our previous work showed that in vitro murine macrophages rely on the viable but not cultivable (VBNC-a dormancy phenotype) fungus from active Cn, with striking differences in immunometabolic gene expression. Here, we analyzed the influence of VBNC and active Cn on the immunometabolism of infected macrophages, combining metabolic gene expression, mitochondrial membrane potential (ΔΨm), oxygen consumption analysis, and uptake of glucose and fatty acids. The active fungus induced mitochondrial depolarization, and increased glycolysis and mitochondrial oxygen consumption. VBNC infection in bone marrow-derived macrophage (BMDM) caused an attenuated modification in mitochondrial metabolism. However, we found differences in BMDM infected with VBNC vs those infected with active fungus, where VBNC induced an increment in fatty acid uptake in M0 and M1 BMDM, measured by incorporation of BODIPY-palmitate, accompanied by an increase in expression of fatty acid transporters Fabp1 and Fabp4. Overall, distinct fatty acid-related responses induced by VBNC and active Cn suggest different immunomodulatory reactions, depending on the microbial growth stage. We posit that, for VBNC, some of these macrophage metabolic responses reflect the establishment of prolonged microbial intracellular residency and possibly initial stages of granuloma formation.

ARIES domains: functional signaling units of type I interferon responses

The innate immune system relies on a network of signaling proteins classified by shared domains, which serve as functional units that orchestrate inflammatory and host defensive activities. Within type I interferon (IFN) responses, the stimulator of interferon genes protein (STING), mitochondrial antiviral-signaling protein (MAVS), Toll-IL-1 receptor-resistance protein domain-containing adapter-inducing interferon-β (TRIF), Toll-like receptor adapter interacting with SLC15A4 on the lysosome (TASL), insulin receptor tyrosine kinase substrate protein of 53 kDa (IRSp53), and GEM interacting protein (GMIP) utilize a conserved pLxIS motif to recruit IRF family transcription factors. Notably, the pLxIS motif functions within a larger signaling unit, which is referred to here as an Activator of Interferon Expression via a pLxIS motif (ARIES) domain. ARIES domains consist of the pLxIS motif and adjacent kinase activation motifs that together drive IFN responses. This review explores how ARIES domains promote immune responses via shared and distinct signaling mechanisms, protein localization, and regulation of metabolic shifts, underscoring their evolutionary conservation and critical role in host defense.

Lipid Metabolism: An Emerging Player in Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disorder that primarily affects the exocrine glands. Due to the intricate nature of the disease progression, the exact mechanisms underlying SS are not completely understood. Recent research has highlighted the complex interplay between immune dysregulation and metabolic abnormalities in inflammatory diseases. Notably, lipid metabolism has emerged as a crucial factor in the modulation of immune function and the progression of autoimmune diseases, including SS. This review explores the prevalence of dyslipidemia in SS, emphasizing its role in the onset, progression, and prognosis of the disease. We specifically described the impact of altered lipid metabolism in exocrine glands and its association with disease-specific features, including inflammation and glandular dysfunction. Additionally, we discussed the potential clinical implications of lipid metabolism regulation, including the role of polyunsaturated fatty acids (PUFAs) and their deficits in SS pathogenesis. By identifying lipid metabolism as a promising therapeutic target, this review highlights the need for further research into lipid-based interventions for the management of SS.

Airway macrophage glycolysis controls lung homeostasis and responses to aeroallergen

The lungs represent a dynamic microenvironment where airway macrophages (AMs) are the major lung-resident macrophages. AMs dictate the balance between tissue homeostasis and immune activation and thus have contradictory functions by maintaining tolerance and tissue homeostasis, as well as initiating strong inflammatory responses. Emerging evidence has highlighted the connection between macrophage function and cellular metabolism. However, the functional importance of these processes in tissue-resident specialized macrophage populations such as those found in the airways, remain poorly elucidated. Here, we reveal that glycolysis is a fundamental pathway in AMs which regulates both lung homeostasis and responses to inhaled allergen. Using macrophage specific targeting in vivo, and multi-omics approaches, we determined that glycolytic activity in AMs is necessary to restrain type 2 (T2) immunity during homeostasis. Exposure to a range of common aeroallergens, including house dust mite (HDM), drove AM-glycolysis and furthermore, AM-specific inhibition of glycolysis altered inflammation in the airways and HDM-driven airway metabolic adaptations in vivo. Additionally, allergen sensitised asthmatics had profound metabolic changes in the airways, compared to non-sensitised asthmatic controls. Finally, we found that allergen driven AM-glycolysis in mice was TLR2 dependent. Thus, our findings demonstrate a direct relationship between glycolysis in AMs, AM-mediated homeostatic processes, and T2 immune responses in the lungs. These data suggest that glycolysis is essential for the plasticity of AMs. Depending on the immunological context, AM-glycolysis is required to exert homeostatic activity but once activated by allergen, AM-glycolysis influences inflammatory responses. Thus, precise modulation of glycolytic activity in AMs is essential for preserving lung homeostasis and regulating airway inflammation.

Breathing new insights into the role of mutant p53 in lung cancer

The tumour suppressor gene p53 is one of the most frequently mutated genes in lung cancer and these defects are associated with poor prognosis, albeit some debate exists in the lung cancer field. Despite extensive research, the exact mechanisms by which mutant p53 proteins promote the development and sustained expansion of cancer remain unclear. This review will discuss the cellular responses controlled by p53 that contribute to tumour suppression, p53 mutant lung cancer mouse models and characterisation of p53 mutant lung cancer. Furthermore, we discuss potential approaches of targeting mutant p53 for the treatment of lung cancer.

Striking a balance: new perspectives on homeostatic dendritic cell maturation

Dendritic cells (DCs) are crucial gatekeepers of the balance between immunity and tolerance. They exist in two functional states, immature or mature, that refer to an information-sensing versus an information-transmitting state, respectively. Historically, the term DC maturation was used to describe the acquisition of immunostimulatory capacity by DCs following their triggering by pathogens or tissue damage signals. As such, immature DCs were proposed to mediate tolerance, whereas mature DCs were associated with the induction of protective T cell immunity. Later studies have challenged this view and unequivocally demonstrated that two distinct modes of DC maturation exist, homeostatic and immunogenic DC maturation, each with a distinct functional outcome. Therefore, the mere expression of maturation markers cannot be used to predict immunogenicity. How DCs become activated in homeostatic conditions and maintain tolerance remains an area of intense debate. Several recent studies have shed light on the signals driving the homeostatic maturation programme, especially in the conventional type 1 DC (cDC1) compartment. Here, we highlight our growing understanding of homeostatic DC maturation and the relevance of this process for immune tolerance.

Circadian metabolic adaptations to infections

Circadian clocks are biological oscillators that evolved to coordinate rhythms in behaviour and physiology around the 24-hour day. In mammalian tissues, circadian rhythms and metabolism are highly intertwined. The clock machinery controls rhythmic levels of circulating hormones and metabolites, as well as rate-limiting enzymes catalysing biosynthesis or degradation of macromolecules in metabolic tissues, such control being exerted both at the transcriptional and post-transcriptional level. During infections, major metabolic adaptation occurs in mammalian hosts, at the level of both the single immune cell and the whole organism. Under these circumstances, the rhythmic metabolic needs of the host intersect with those of two other players: the pathogen and the microbiota. These three components cooperate or compete to meet their own metabolic demands across the 24 hours. Here, we review findings describing the circadian regulation of the host response to infection, the circadian metabolic adaptations occurring during host-microbiota-pathogen interactions and how such regulation can influence the immune response of the host and, ultimately, its own survival.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.

Adropin: a key player in immune cell homeostasis and regulation of inflammation in several diseases

Adropin is a secreted peptide encoded by the energy homeostasis-associated gene (ENHO), located chromosome 9p13.3, with a conserved amino acid sequence across humans and mice. Its expression is regulated by various factors, including fat, LXRα, ERα, ROR, and STAT3. Adropin plays a critical role in glucose and lipid metabolism, as well as insulin resistance, by modulating multiple signaling pathways that contribute to the reduction of obesity and the improvement of blood lipid and glucose homeostasis. Additionally, it influences immune cells and inflammation, exerting anti-inflammatory effects across various diseases. While extensive research has summarized the regulation of cellular energy metabolism by adropin, limited studies have explored its role in immune regulation and inflammation. To enhance the understanding of adropin's immune-modulating and anti-inflammatory mechanisms, this review synthesizes recent findings on its effects in conditions such as atherosclerosis, diabetes, fatty liver, non-alcoholic hepatitis, and inflammation. Furthermore, the review discusses the current research limitations and outlines potential future directions for adropin-related investigations. It is hoped that ongoing research into adropin will contribute significantly to the advancement of medical treatments for various diseases.

Toll-like receptors in mammalian sperm

Background

Toll-like receptors (TLRs) are critical components of the innate immune system and are expressed in various cells, including the reproductive system. Although their roles in female reproductive tissues such as the ovaries and uterus, including their involvement in fertilization and implantation, have been extensively reviewed, their expression and function in male germ cells, particularly in sperm, remain underexplored.

Methods

This review provides a comprehensive summary of research on TLRs expressed in sperm, including findings from experimental models in mice, humans, and industrial livestock.

Results

The activation of TLR2 and TLR4, which detect Gram-positive and Gram-negative bacteria, has been shown to reduce sperm motility and viability, thereby impairing fertilization. Conversely, low levels of TLR2 activation have been reported to promote the fertilization of bull sperm, suggesting that TLR2/4 may act as regulators of fertilization. TLR7 and TLR8, which are exclusively expressed in X chromosome-bearing sperm (X-sperm), have attracted increasing research interest. These receptors modulate sperm metabolism, selectively reduce the motility of X sperm, and enable the separation of X and Y sperm.

Conclusion

TLRs in the sperm serve as immune receptors that detect bacterial and viral infections, thereby reducing sperm functionality, preventing miscarriage, protecting maternal health, and sex selection.

Dendritic cell immunometabolism - a potential therapeutic target for allergic diseases

Allergic diseases are a group of chronic inflammatory disorders driven by abnormal immune responses. Dendritic cells (DCs) play a pivotal role in the initiation and progression of allergic diseases by modulating T cell responses. Extensive progress has been made in characterizing crucial roles of metabolic reprogramming in the regulation of immune cell functions. As the critical upstream regulators and effectors in allergic responses, the activation, migration, and function of DCs are reliant on metabolic reprogramming. In this review, we summarize the metabolic characteristics of DCs, and how the cellular microenvironment shapes DC function. We also elucidate the metabolic regulation of DC biology in the context of allergic diseases and targeted therapeutic strategies based on DC metabolism regulation. Understanding the functional alterations in DCs during allergic responses and the underlying mechanisms governing its metabolic regulation is crucial for the development of effective strategies for the prevention and treatment of allergic diseases.

Agmatine suppresses glycolysis via the PI3K/Akt/mTOR/HIF-1α signaling pathway and improves mitochondrial function in microglia exposed to lipopolysaccharide

Modulating metabolic pathways in activated microglia can alter their phenotype, which is relevant in uncontrolled neuroinflammation as a component of various neurodegenerative diseases. Here, we investigated how pretreatment with agmatine, an endogenous polyamine, affects metabolic changes in an in vitro model of neuroinflammation, a murine microglial BV-2 cell line exposed to lipopolysaccharide (LPS). Hence, we analyzed gene expression using qPCR and protein levels using Western blot and ELISA. Microglial metabolic status was assessed by measuring lactate release and cellular ATP by enzymatic and luminescence spectrophotometry. Mitochondrial functionality was analyzed by fluorescent probes detecting mitochondrial membrane potential (mtMP) and superoxide production. Our findings suggest that kinase pathways associated with hypoxia-inducible factor-1α (HIF-1α) regulate energy metabolism in pro-inflammatory activated microglia. We have shown that LPS induces HIF-1α and genes for glucose transporter and glycolytic rate, increases lactate production and causes mitochondrial dysfunction, suggesting a metabolic shift towards glycolysis. Agmatine inhibits the PI3K/Akt pathway and negatively regulates mammalian target of rapamycin (mTOR) phosphorylation and HIF-1α levels, reducing lactate and tumor necrosis factor (TNF) production, which is supported by pharmacological blockade of PI3K. Pretreatment with agmatine also rescues mitochondrial function by counteracting the LPS-induced decline in mtMP and increase in mitochondrial superoxide, resulting in an anti-apoptotic effect. Agmatine alone increases intracellular ATP levels and maintains this effect even under pro-inflammatory conditions. Our study emphasizes the ability of agmatine to engage in metabolic reprogramming of pro-inflammatory microglia through increased ATP production and modulation of signaling pathway involved in promoting glycolysis and cytokine release.

Impact of zinc on immunometabolism and its putative role on respiratory diseases

Zinc is the second most abundant trace mineral in the human body and plays a critical role in immune cell function and metabolism. Zinc deficiency impairs immune cell function and is associated with increased susceptibility to respiratory diseases, including pneumonia, influenza, and COVID-19. Zinc homeostasis, maintained by numerous zinc transporters and metal-binding proteins (ie, metallothionein), is essential for coordinating immune cell signaling, gene expression, and enzymatic activities in response to respiratory infections. This article highlights the emerging role of zinc in various aspects of immune function, particularly through its influence on cellular metabolism. Given the significant global burden of respiratory diseases, there is a need to identify effective nutritional interventions that could be readily leveraged to prevent and/or mitigate respiratory disease risk, particularly in older adults who are prone to zinc deficiency. However, the immunometabolic mechanisms underlying zinc's protective effects remain poorly characterized. Future research should focus on elucidating how micronutrients, such as zinc, can support changes in immune cell metabolism in response to infections. Such efforts will help determine how zinc metabolism and zinc intervention strategies may best be leveraged to prevent or mitigate respiratory disease.

Metabolism at the crossroads of inflammation and fibrosis in chronic kidney disease

Chronic kidney disease (CKD), defined as persistent (>3 months) kidney functional loss, has a growing prevalence (>10% worldwide population) and limited treatment options. Fibrosis driven by the aberrant accumulation of extracellular matrix is the final common pathway of nearly all types of chronic repetitive injury in the kidney and is considered a hallmark of CKD. Myofibroblasts are key extracellular matrix-producing cells that are activated by crosstalk between damaged tubules and immune cells. Emerging evidence indicates that metabolic alterations are crucial contributors to the pathogenesis of kidney fibrosis by affecting cellular bioenergetics and metabolite signalling. Immune cell functions are intricately connected to their metabolic characteristics, and kidney cells seem to undergo cell-type-specific metabolic shifts in response to damage, all of which can determine injury and repair responses in CKD. A detailed understanding of the heterogeneity in metabolic reprogramming of different kidney cellular subsets is essential to elucidating communication processes between cell types and to enabling the development of metabolism-based innovative therapeutic strategies against CKD.

The immunological interface: dendritic cells as key regulators in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) refers to a broad spectrum of conditions associating fat accumulation in the liver (steatosis) with varying degrees of inflammation (hepatitis) and fibrosis, which can progress to cirrhosis and potentially cancer (hepatocellular carcinoma). The first stages of these diseases are reversible and the immune system, together with metabolic factors (obesity, insulin resistance, Western diet, etc.), can influence the disease trajectory leading to progression or regression. Dendritic cells are professional antigen-presenting cells that constantly sense environmental stimuli and orchestrate immune responses. Herein, we discuss the existing literature on the heterogeneity of dendritic cell lineages, states, and functions, to provide a comprehensive overview of how liver dendritic cells influence the onset and evolution of MASLD.

GM-CSF engages multiple signaling pathways to enhance pro-inflammatory cytokine responses in human monocytes during Legionella infection

The proinflammatory cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) is required for host defense against a wide range of pathogens. We previously found that GM-CSF enhances inflammatory cytokine production in murine monocytes and is required for in vivo control of the intracellular bacterial pathogen Legionella pneumophila . It is unclear whether GM-CSF similarly augments cytokine production in human monocytes during bacterial infection. Here, we find that GM-CSF enhances inflammatory cytokine expression in Legionella- infected human monocytes by engaging multiple signaling pathways. Legionella - and TLR-dependent NF-𝜅B signaling is a prerequisite signal for GM-CSF to promote cytokine expression. Then, GM-CSF-driven JAK2/STAT5 signaling is required to augment cytokine expression in Legionella -infected human monocytes. We also found a role for PI-3K/Akt/mTORC1 signaling in GM-CSF-dependent upregulation of cytokine expression. Finally, glycolysis and amino acid metabolism are also critical for GM-CSF to boost cytokine gene expression in human monocytes during infection. Our findings show that GM-CSF-mediated enhancement of cytokine expression in infected human monocytes is regulated by multiple signaling pathways, thereby allowing the host to fine tune antibacterial immunity.

The impact of glucose metabolism on inflammatory processes in sepsis-induced acute lung injury

Acute lung injury (ALI) is a prevalent and critical complication of sepsis, marked by high incidence and mortality rates, with its pathogenesis still not being fully elucidated. Recent research has revealed a significant correlation between the metabolic reprogramming of glucose and sepsis-associated ALI (S-ALI). Throughout the course of S-ALI, immune cells, including macrophages and dendritic cells, undergo metabolic shifts to accommodate the intricate demands of immune function that emerge as sepsis advances. Indeed, glucose metabolic reprogramming in S-ALI serves as a double-edged sword, fueling inflammatory immune responses in the initial stages and subsequently initiating anti-inflammatory responses as the disease evolves. In this review, we delineate the current research progress concerning the pathogenic mechanisms linked to glucose metabolic reprogramming in S-ALI, with a focus on the pertinent immune cells implicated. We encapsulate the impact of glucose metabolic reprogramming on the onset, progression, and prognosis of S-ALI. Ultimately, by examining key regulatory factors within metabolic intermediates and enzymes, We have identified potential therapeutic targets linked to metabolic reprogramming, striving to tackle the inherent challenges in diagnosing and treating Severe Acute Lung Injury (S-ALI) with greater efficacy.

Measuring the rate of NADPH consumption by glutathione reductase in the cytosol and mitochondria

BACKGROUND

NADPH is an essential co-factor supporting the function of enzymes that participate in both inflammatory and anti-inflammatory pathways in myeloid cells, particularly macrophages. Although individual NADPH-dependent pathways are well characterized, how these opposing pathways are co-regulated to orchestrate an optimized inflammatory response is not well understood. To investigate this, techniques to track the consumption of NADPH need to be applied. Deuterium tracing of NADPH remains the gold standard in the field, yet this setup of mass-spectrometry is technically challenging and not readily available to most research groups. Furthermore, NADPH pools are compartmentalized in various organelles with no known membrane transporters, suggesting that NADPH-dependent pathways are regulated in an organelle-specific manner. Conventional methods such as commercial kits are limited to quantifying NADPH in whole cells and not at the resolution of specific organelles. These limitations reflect the need for a novel assay that can readily measure the consumption rate of NADPH in different organelles.

METHODS

We devised an assay that measures the consumption rate of NADPH by glutathione-disulfide reductase (GSR) in the mitochondria and the cytosol of RAW264.7 macrophage cell lines. RAW264.7 cells were transfected with Apollo-NADP+ sensors targeted to the mitochondria or the cytosol, followed by the treatment of 2-deoxyglucose and diamide. Intravital imaging over time then determined GSR-dependent NADPH consumption in an organelle-specific manner.

DISCUSSION

In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, cytosolic and mitochondrial NADPH was consumed by GSR in a time-dependent manner. This finding was cross validated with a commercially available NADPH kit that detects NADPH in whole cells. Loading of RAW264.7 cells with oxidized low-density lipoprotein followed by LPS stimulation elevated GSR expression, and this correlated with a more rapid drop in cytosolic and mitochondrial NADPH in our assay. The current limitation of our assay is applicability to transfectable cell lines, and higher expression of plasmid-encoded sensors relative to endogenous glucose-6-phosphate dehydrogenase.

The role of the interplay between macrophage glycolytic reprogramming and NLRP3 inflammasome activation in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a severe respiratory condition associated with elevated morbidity and mortality. Understanding their complex pathophysiological mechanisms is crucial for developing new preventive and therapeutic strategies. Recent studies highlight the significant role of inflammation involved in ALI/ARDS, particularly the hyperactivation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome in macrophages. This activation drives pulmonary inflammation by releasing inflammatory signalling molecules and is linked to metabolic reprogramming, marked by increased glycolysis and reduced oxidative phosphorylation. However, the relationship between NLRP3 inflammasome activation and macrophage glycolytic reprogramming in ALI/ARDS, as well as the molecular mechanisms regulating these processes, remain elusive. This review provides a detailed description of the interactions and potential mechanisms linking NLRP3 inflammasome activation with macrophage glycolytic reprogramming, proposing that glycolytic reprogramming may represent a promising therapeutic target for mitigating inflammatory responses in ALI/ARDS. KEY POINTS: NLRP3 inflammasome activation is pivotal in mediating the excessive inflammatory response in ALI/ARDS. Glycolytic reprogramming regulates NLRP3 inflammasome activation. Therapeutic potential of targeting glycolytic reprogramming to inhibit NLRP3 inflammasome activation in ALI/ARDS.

UBXN9 governs GLUT4-mediated spatial confinement of RIG-I-like receptors and signaling

The cytoplasmic RIG-I-like receptors (RLRs) recognize viral RNA and initiate innate antiviral immunity. RLR signaling also triggers glycolytic reprogramming through glucose transporters (GLUTs), whose role in antiviral immunity is elusive. Here, we unveil that insulin-responsive GLUT4 inhibits RLR signaling independently of glucose uptake in adipose and muscle tissues. At steady state, GLUT4 is trapped at the Golgi matrix by ubiquitin regulatory X domain 9 (UBXN9, TUG). Following RNA virus infection, GLUT4 is released and translocated to the cell surface where it spatially segregates a significant pool of cytosolic RLRs, preventing them from activating IFN-β responses. UBXN9 deletion prompts constitutive GLUT4 translocation, sequestration of RLRs and attenuation of antiviral immunity, whereas GLUT4 deletion heightens RLR signaling. Notably, reduced GLUT4 expression is uniquely associated with human inflammatory myopathies characterized by hyperactive interferon responses. Overall, our results demonstrate a noncanonical UBXN9-GLUT4 axis that controls antiviral immunity via plasma membrane tethering of cytosolic RLRs.

Qingshen granules inhibits dendritic cell glycolipid metabolism to alleviate renal fibrosis via PI3K-AKT-mTOR pathway

BACKGROUND

Qingshen exhibits anti-inflammatory and immunoregulation effects to renal damage. Dendritic cells (DCs) play a critical role in regulating the pathologic inflammatory environment in renal fibrosis (RF).

PURPOSE

To investigate the immune modulation mechanism of qingshen granule (QSG) in RF, particularly focusing on the role of DCs.

METHODS/STUDY DESIGN

Adenine-induced RF animal models were used to study the pharmacological effects of QSG and the immune cells differentiation and function. Glucose uptake, non-esterified fatty acids secretion, mitochondrial membrane potential (MMP) detection, and qPCR were used to explore the effect of QSG to glucose and lipid metabolism in DCs and T cells. The effect of QSG to PI3K-AKT-mTOR axis and the modulation of mTOR to PD-L1 were explored by co-culture experiments, co-immunoprecipitation and western blot assays. The interaction of DCs/CD8+T cells and renal tubular epithelial cells (RTECs) was investigated to demonstrate the direct action and/or the immune-mediated regulation of QSG to RF. The components of QSG in the serum were determined by HPLC. And the effect of active ingredients and formula to DCs and T cells was analyzed by cell experiments in vitro.

RESULTS

QSG reduced nephritic histopathological damage and suppressed the release of proinflammatory cytokines in adenine-induced RF mice. Of note, QSG decreased the levels of CD86, MHC-II, and CCR7 on DCs, while, increased PD-L1 expression on DCs in RF. The results demonstrated that QSG promoted the maturation and inhibited the migration of DCs, and QSG decreased the antigen presenting of DCs to T cells. Additionally, QSG reduced the MMP and glucose/lipid utilization ratio in DCs. QSG also down-regulated the level of targeted metabolic genes included glucose transporter 1 (Glut1), sterol-regulatory element-binding protein 1 (Srebp1), acetyl-CoA carboxylase alpha (Acaca), phosphomevalonate kinase (Pmvk), and up-regulated sirtuin2 (Sirt2) in DCs. In terms of mechanism, QSG inhibited the metabolism-related PI3K-AKT-mTOR pathway, followed by regulating the interaction of mTOR with PD-L1 to enhance the membrane stability of PD-L1. Besides, HPLC analysis identified five active ingredients in QSG. The specific anti-inflammatory and immunosuppressive actions of these ingredients were found to be weaker than QSG as a whole. Finally, inhibiting DC function by QSG disrupted the communication among DCs, T cells, and RTECs. This disruption was associated with low expression of α-smooth muscle actin (α-SMA) and collagen type I (Col-I) in the kidney.

CONCLUSIONS

QSG inhibits DC metabolism and function via the PI3K-AKT-mTOR pathway to alleviate RF. The study highlights the importance of the specific composition of the formula in targeting DC-mediated immune regulation.

Glycolytic reprogramming in microglia: A potential therapeutic target for ischemic stroke

Ischemic stroke is currently the second leading cause of mortality worldwide, with limited treatment options available. As resident immune cells, microglia promptly respond to cerebral ischemic injury, influencing neuroinflammatory damage and neurorepair. Studies suggest that microglia undergo metabolic reprogramming from mitochondrial oxidative phosphorylation to glycolysis in response to ischemia, significantly impacting their function during ischemic stroke. Therefore, this study aims to investigate the roles and regulatory mechanisms involved in this process, aiming to identify a new therapeutic target or potential drug candidate.

Crosstalk and Prospects of TBK1 in Inflammation

BACKGROUND

TANK-binding kinase 1 (TBK1) is a pivotal mediator of innate immunity, activated by receptors such as mitochondrial antiviral signaling protein (MAVS), stimulator of interferon genes (STING), and TIR-domain-containing adaptor inducing interferon-β (TRIF). It modulates immune responses by exerting influence on the type I interferons (IFN-Is) signaling and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, Over the past few years, TBK1 multifaceted role in both immune and inflammatory responses is increasingly recognized.

METHODS AND RESULTS

This review aims to scrutinize how TBK1 operates within the NF-κB pathway and the interferon regulatory transcription factor 3 (IRF3)-dependent IFN-I pathways, highlighting the kinases and other molecules involved in these processes. This analysis reveals the distinctive characteristics of TBK1's involvement in these pathways. Furthermore, it has been observed that the role of TBK1 in exerting anti-inflammatory or pro-inflammatory effects is contingent upon varying pathological conditions, indicating a multifaceted role in immune regulation.

DISCUSSION

TBK1's evolving role in various diseases and the potential of TBK1 inhibitors as therapeutic agents are explored. Targeting TBK1 may provide new strategies for treating inflammatory disorders and autoimmune diseases associated with IFN-Is, warranting further investigation.

Target modulation of glycolytic pathways as a new strategy for the treatment of neuroinflammatory diseases

Neuroinflammation is an innate and adaptive immune response initiated by the release of inflammatory mediators from various immune cells in response to harmful stimuli. While initially beneficial and protective, prolonged or excessive neuroinflammation has been identified in clinical and experimental studies as a key pathological driver of numerous neurological diseases and an accelerant of the aging process. Glycolysis, the metabolic process that converts glucose to pyruvate or lactate to produce adenosine 5'-triphosphate (ATP), is often dysregulated in many neuroinflammatory disorders and in the affected nerve cells. Enhancing glucose availability and uptake, as well as increasing glycolytic flux through pharmacological or genetic manipulation of glycolytic enzymes, has shown potential protective effects in several animal models of neuroinflammatory diseases. Modulating the glycolytic pathway to improve glucose metabolism and ATP production may help alleviate energy deficiencies associated with these conditions. In this review, we examine six neuroinflammatory diseases-stroke, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and depression-and provide evidence supporting the role of glycolysis in their treatment. We also explore the potential link between inflammation-induced aging and glycolysis. Additionally, we briefly discuss the critical role of glycolysis in three types of neuronal cells-neurons, microglia, and astrocytes-within physiological processes. This review highlights the significance of glycolysis in the pathology of neuroinflammatory diseases and its relevance to the aging process.

Phenotypic Heterogeneity in Pathogens

Pathogen diversity within an infected organism has traditionally been explored through the lens of genetic heterogeneity. Hallmark studies have characterized how genetic diversity within pathogen subpopulations contributes to treatment escape and infectious disease progression. However, recent studies have begun to reveal the mechanisms by which phenotypic heterogeneity is established within genetically identical populations of invading pathogens. Furthermore, exciting new work highlights how these phenotypically heterogeneous subpopulations contribute to a pathogen population better equipped to handle the complex and fluctuating environment of a host organism. In this review, we focus on how bacterial pathogens, including Staphylococcus aureus, Salmonella typhimurium, Pseudomonas aeruginosa, and Mycobacterium tuberculosis, establish and maintain phenotypic heterogeneity, and we explore recent work demonstrating causative links between this heterogeneity and infection outcome.

The role of inflammatory response and metabolic reprogramming in sepsis-associated acute kidney injury: mechanistic insights and therapeutic potential

Sepsis represents a severe condition characterized by organ dysfunction resulting from a dysregulated host response to infection. Among the organs affected, the kidneys are particularly vulnerable, with significant functional impairment that markedly elevates mortality rates. Previous researches have highlighted that both inflammatory response dysregulation and metabolic reprogramming are crucial in the onset and progression of sepsis associated acute kidney injury (SA-AKI), making these processes potential targets for innovative therapies. This study aims to elucidate the pathophysiological mechanisms of renal injury in sepsis by perspective of inflammatory response dysregulation, with particular emphasis on pyroptosis, necroptosis, autophagy, and ferroptosis. Furthermore, it will incorporate insights into metabolic reprogramming to provide a detailed analysis of the mechanisms driving SA-AKI and explore potential targeted therapeutic strategies, providing solid theoretical framework for the development of targeted therapies for SA-AKI.

Integrated temporal transcriptional and epigenetic single-cell analysis reveals the intrarenal immune characteristics in an early-stage model of IgA nephropathy during its acute injury

Rationale

Kidney inflammation plays a crucial role in the pathogenesis of IgA nephropathy (IgAN), yet the specific phenotypes of immune cells involved in disease progression remain incompletely understood. Utilizing joint profiling through longitudinal single-cell RNA-sequencing (scRNAseq) and single-cell assay for transposase-accessible chromatin sequencing (scATACseq) can provide a comprehensive framework for elucidating the development of cell subset diversity and how chromatin accessibility regulates transcription.

Objective

We aimed to characterize the dynamic immune cellular landscape at a high resolution in an early IgAN mouse model with acute kidney injury (AKI).

Methods and results

A murine model was utilized to mimic 3 immunological states -"immune stability (IS), immune activation (IA) and immune remission (IR)" in early human IgAN-associated glomerulopathy during AKI, achieved through lipopolysaccharide (LPS) injection. Urinary albumin to creatinine ratio (UACR) was measured to further validate the exacerbation and resolution of kidney inflammation during this course. Paired scRNAseq and scATACseq analysis was performed on CD45+ immune cells isolated from kidney tissues obtained from CTRL (healthy vehicle), IS, IA and IR (4 or 5 mice each). The analyses revealed 7 major cell types and 24 clusters based on 72304 single-cell transcriptomes, allowing for the identification and characterization of various immune cell types within each cluster. Our data offer an impartial depiction of the immunological characteristics, as the proportions of immune cell types fluctuated throughout different stages of the disease. Specifically, these analyses also revealed novel subpopulations, such as a macrophage subset (Nlrp1b Mac) with distinct epigenetic features and a unique transcription factor motif profile, potentially exerting immunoregulatory effects, as well as an early subset of Tex distinguished by their effector and cytolytic potential (CX3CR1-transTeff). Furthermore, in order to investigate the potential interaction between immune cells and renal resident cells, we conducted single-cell RNA sequencing on kidney cells obtained from a separate cohort of IS and IA mice without isolating immune cells. These findings underscored the diverse roles played by macrophages and CD8+ T cells in maintaining homeostasis of endothelial cells (ECs) under stress.

Conclusions

This study presents a comprehensive analysis of the dynamic changes in immune cell profiles in a model of IgAN, identifying key cell types and their roles and interactions. These findings significantly contribute to the understanding of the pathogenesis of IgAN and may provide potential targets for therapeutic intervention.

AMPK activation induces RALDH+ tolerogenic dendritic cells by rewiring glucose and lipid metabolism

Dendritic cell (DC) activation and function are underpinned by profound changes in cellular metabolism. Several studies indicate that the ability of DCs to promote tolerance is dependent on catabolic metabolism. Yet the contribution of AMP-activated kinase (AMPK), a central energy sensor promoting catabolism, to DC tolerogenicity remains unknown. Here, we show that AMPK activation renders human monocyte-derived DCs tolerogenic as evidenced by an enhanced ability to drive differentiation of regulatory T cells, a process dependent on increased RALDH activity. This is accompanied by several metabolic changes, including increased breakdown of glycerophospholipids, enhanced mitochondrial fission-dependent fatty acid oxidation, and upregulated glucose catabolism. This metabolic rewiring is functionally important as we found interference with these metabolic processes to reduce to various degrees AMPK-induced RALDH activity as well as the tolerogenic capacity of moDCs. Altogether, our findings reveal a key role for AMPK signaling in shaping DC tolerogenicity and suggest AMPK as a target to direct DC-driven tolerogenic responses in therapeutic settings.

Metabolic reprogramming of the inflammatory response in the nervous system: the crossover between inflammation and metabolism

Metabolism is a fundamental process by which biochemicals are broken down to produce energy (catabolism) or used to build macromolecules (anabolism). Metabolism has received renewed attention as a mechanism that generates molecules that modulate multiple cellular responses. This was first identified in cancer cells as the Warburg effect, but it is also present in immunocompetent cells. Studies have revealed a bidirectional influence of cellular metabolism and immune cell function, highlighting the significance of metabolic reprogramming in immune cell activation and effector functions. Metabolic processes such as glycolysis, oxidative phosphorylation, and fatty acid oxidation have been shown to undergo dynamic changes during immune cell response, facilitating the energetic and biosynthetic demands. This review aims to provide a better understanding of the metabolic reprogramming that occurs in different immune cells upon activation, with a special focus on central nervous system disorders. Understanding the metabolic changes of the immune response not only provides insights into the fundamental mechanisms that regulate immune cell function but also opens new approaches for therapeutic strategies aimed at manipulating the immune system.

The effects of in vitro vitamin D treatment on glycolytic reprogramming of bone marrow-derived dendritic cells from Ldlr knock-out mouse

Dendritic cells (DCs) undergo glycolytic reprogramming, a metabolic conversion process essential for their activation. Vitamin D has been reported to affect the function of DCs, but studies in metabolic diseases are insufficient. This study investigates the effects of in vitro 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) treatment on glycolytic reprogramming of bone marrow-derived dendritic cells (BMDCs) from control, obese, and atherosclerosis mice. Six-week-old male C57BL/6J mice were fed a control diet (CON) or a Western diet (WD), and B6.129S7-Ldlrtm1Her/J mice were fed a Western diet (LDLR-/-) for 16 weeks. BMDCs were cultured in a medium containing 1,25(OH)2D3 (10 nM) for 7 days and stimulated with lipopolysaccharide (LPS, 50 ng/mL) for 24 h. In mature BMDCs, 1,25(OH)2D3 treatment decreased basal and compensatory glycolytic proton efflux rates (glycoPER), the expression of surface markers related to immune function of DCs (MHC class II, CD80, and CD86), and IL-12p70 production. In addition, mTORC1 activation and nitric oxide (NO) production were suppressed by 1,25(OH)2D3 treatment in mature BMDCs. The effect of 1,25(OH)2D3 treatment on IL-12p70 production and mTORC1 activity in the LDLR-/- group was greater than in the CON group. These findings suggest that vitamin D can affect the metabolic environment of BMDCs by regulating glycolytic reprogramming as well as by inducing tolerogenic phenotypes of DCs.