PKM2 regulates the Warburg effect and promotes HMGB1 release in sepsis

Utilization of lactate trajectory models for predicting acute kidney injury and mortality in patients with hyperlactatemia: insights across three independent cohorts

This study aims to investigate the association between lactate trajectories and the risk of acute kidney injury (AKI) and hospital mortality in patients with hyperlactatemia. We conducted a multicenter retrospective study using data from three independent cohorts. By the lactate levels during the first 48 h of ICU admission, patients were classified into distinct lactate trajectories using group-based trajectory modeling (GBTM) method. The primary outcomes were AKI incidence and hospital mortality. Logistic regression analysis assessed the association between lactate trajectories and clinical outcomes, with adjusting potential confounders. Patients were divided into three trajectories: mild hyperlactatemia with rapid recovery (Traj-1), severe hyperlactatemia with gradual recovery (Traj-2), and severe hyperlactatemia with persistence (Traj-3). Traj-3 was an independent risk factor of both hospital mortality (all p < 0.001) and AKI development (all p < 0.001). Notably, Traj-2 was also associated with increased risk of mortality and AKI development (all p < 0.05) using Traj-1 as reference, except for the result in the Tianjin Medical University General Hospital (TMUGH) cohort for mortality in adjusted model (p = 0.123). Our finding was still robust in subgroup and sensitivity analysis. In the combination cohort, both Traj-2 and Traj-3 were considered as independent risk factor for hospital mortality and AKI development (all p < 0.001). When compared with the Traj-3, Traj-2 was only significantly associated with the decreased risk of hospital mortality (OR 0.17, 95% CI 0.14-0.20, p < 0.001), but no with the likelihood of AKI development (OR 0.90, 95% CI 0.77-1.05, p = 0.172). Lactate trajectories provide valuable information for predicting AKI and mortality in critically ill patients.

Moonlighting functions of glucose metabolic enzymes and metabolites in cancer

Glucose metabolic enzymes and their metabolites not only provide energy and building blocks for synthesizing macromolecules but also possess non-canonical or moonlighting functions in response to extracellular and intracellular signalling. These moonlighting functions modulate various cellular activities, including gene expression, cell cycle progression, DNA repair, autophagy, senescence and apoptosis, cell proliferation, remodelling of the tumour microenvironment and immune responses. These functions integrate glucose metabolism with other essential cellular activities, driving cancer progression. Targeting these moonlighting functions could open new therapeutic avenues and lead to cancer-specific treatments.

MicroRNA-122 regulates inflammatory and autophagic proteins by downregulating pyruvate kinase M2 in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the serious global health concerns, leading to non-alcoholic steatohepatitis (NASH), and to hepatocellular carcinoma (HCC). Despite its prevalence, the molecular mechanisms regulating NAFLD progression remain elusive. The present study aims to determine role of microRNA-122-mediated regulation of pyruvate kinase M2 (PKM2) on regulating inflammatory and autophagic proteins during the pathogenesis of NAFLD. Huh7 cells were incubated with free fatty acids (FFAs) or transfected with single guide RNA to PKM2 containing CRISPR-Cas9 system or miR-122 for up to 72 h. C57BL/6 mice were fed with sham-operated control, choline sufficient L-amino acid defined (CSAA) or choline-deficient L-amino acid defined (CDAA) diet for 6, 18, 32 and 54 weeks. The RNA or protein was isolated from the Huh7 cells and the liver tissue of the mice. RT-PCR was performed for miR-122 expression and Western blots were performed for PKM2, iNOS, COX2, Beclin-1, Atg7 and LC3-II. FFAs induced the expression of PKM2, iNOS and COX2, while decreased the expression of miR-122, Beclin-1, Atg7 and LC3-II. Overexpression of miR-122 resulted in decreased PKM2, iNOS and COX2 and increased Beclin-1, Atg7 and LC3-II. Silencing of PKM2 led to decreased iNOS and COX2 and increased Beclin-1, Atg7 and LC3-II. In CDAA fed-mice, there was a significant increase in PKM2, iNOS and COX2 and decreased miR-122, Beclin-1, Atg7 and LC3-II. The data showed that FFAs downregulated miR-122 expression, which resulted in the upregulation of PKM2, which in turn upregulated inflammatory proteins and downregulated autophagic proteins during the pathogenesis of NAFLD.

Atovaquone-Coordinated Copper-Polyphenol Nanoplatform Orchestrates Dual Metabolic Interference for Synergistic Cuproptosis and Apoptosis

Cuproptosis, a copper-dependent cell death mechanism, is hindered by tumor microenvironment (TME)-driven resistance including glutathione (GSH)-mediated copper detoxification and hypoxia-induced metabolic adaptation. We propose a "dual metabolic interference" strategy to amplify cuproptosis by synergistically targeting iron-sulfur (Fe-S) cluster proteins and suppressing oxidative phosphorylation (OXPHOS). A TME-responsive nanoplatform (ACH NPs) was constructed based on a copper-shikonin coordination network (CuSK), the OXPHOS inhibitor atovaquone (ATO), and hyaluronic acid (HA). Upon GSH/acid-triggered release, Cu+/Cu2+ and ATO/SK synergistically induced irreversible damage: (1) Copper overload induces dihydrolipoamide transacetylase (DLAT) aggregation and irreversible Fe-S cluster loss, directly disrupting mitochondrial complexes I-III functions; (2) ATO further suppresses complex III activity, reducing oxygen consumption and blocking ATP synthesis to exacerbate metabolic crisis; (3) Concurrently, Cu+-catalyzed Fenton-like reactions synergize with SK-driven oxidative stress to generate •OH radicals, activating Caspase-3-dependent apoptosis. In vivo experiments verified that this dual metabolic interference strategy effectively inhibited tumor growth (86.8% tumor suppression). These findings not only expand the theoretical boundaries of cuproptosis but also establish a promising paradigm for cancer therapy through coordinated targeting of metal homeostasis and metabolic vulnerabilities.

SENP1-SIRT3 axis mediates glycolytic reprogramming to suppress inflammation during Listeria monocytogenes infection

Listeria monocytogenes, a foodborne pathogen, has the ability to invade intestinal mucosal cells, undergo intracellular proliferation, activate host immune responses, and induce diseases such as colitis. We have demonstrated that sentrin-specific protease 1 (SENP1) functions as a protective gene in the host, suppressing the inflammatory response triggered by Listeria monocytogenes. The host's SENP1-SIRT3 axis plays a critical role in regulating inflammation during Listeria monocytogenes infection. Our findings reveal that overexpression of SENP1, particularly under Listeria monocytogenes infection conditions (MOI = 20), effectively suppresses inflammation through modulation of glycolysis. Mechanistically, during Listeria monocytogenes infection, SENP1 accumulates in the mitochondria, facilitating the de-SUMOylation and activation of sirtuin 3 (SIRT3). Activated SIRT3 then regulates the deacetylation of pyruvate kinase M2 (PKM2), leading to a decrease in glycolytic intermediates, downregulation of glycolysis-related gene expression, and suppression of inflammation. Taken together, our study provides a deeper understanding of the mechanistic role of the SENP1-SIRT3 axis in the regulation of inflammation, offering novel insights, and strategies for the treatment and prevention of inflammatory diseases.

IMPORTANCE

Sentrin-specific protease 1 (SENP1)-sirtuin 3 (SIRT3) has never been reported in the regulation of bacteria-induced inflammation. Our study demonstrated that SENP1 acted as a protective factor against Listeria-induced inflammation by promoting SIRT3 activation and subsequent metabolic reprogramming. The SENP1-SIRT3 axis served not only as an essential signaling pathway for regulating mitochondrial metabolic responses to metabolic stress but also responds to bacterial invasion and plays a protective role in the organism. Our findings provide a basis for further research into targeting the SENP1-SIRT3 signaling pathway for the treatment of bacterial infections.

Enantiomer-Dependent Uptake of Chiral Nanoparticles in Macrophages Modulates the Inflammatory Response through the NF-κB Pathway

Infectious inflammation caused by pathogens or environmental pollutants remains a major global health issue. Therefore the development of novel strategies to efficaciously control infectious inflammation is urgently required. Nuclear factor-κB (NF-κB) as the central activator of pro-inflammatory genes plays a pivotal role in infectious inflammation. Here, nanoscale chirality was designed to modulate the inflammatory response through enantiomer-dependent blockade of the NF-κB signaling pathway. Chiral gold nanoparticles (AuNPs) with good cytocompatibility were prepared through a one-pot seedless method under wild conditions, showing efficacious alleviation of lipopolysaccharide (LPS)-induced inflammation in vitro and in vivo only by AuNPs with levorotatory chirality (L-AuNPs) rather than the dextrorotatory enantiomer (D-AuNPs). Mechanism investigation elucidated that lysosomal acidification of macrophages was inhibited through a high cellular uptake of L-AuNPs due to their weak interaction energy with cell membranes. Accordingly, the NF-κB rather than mitogen-activated protein kinase pathway was blocked by L-AuNPs through the selective inhibition of p65 phosphorylation, wherein the nuclear translocation of p65 was simultaneously depressed, so the secretion of pro-inflammatory mediators was reduced significantly. This study suggests that imparting chirality to nanoparticles can provide a novel protocol to efficaciously modulate health risks arising from infectious inflammation by improving the uptake of nanoparticles with anti-inflammatory activity.

Targeting the epigenetic regulation of ferroptosis: a potential therapeutic approach for sepsis-associated acute kidney injury

Sepsis is a syndrome of organ dysfunction caused by the invasion of pathogenic microorganisms. In clinical practice, patients with sepsis are prone to concurrent acute kidney injury, which has high morbidity and mortality rates. Thus, understanding the pathogenesis of sepsis-associated acute kidney injury is of significant clinical importance. Ferroptosis is an iron-dependent programmed cell death pathway, which is proved to play a critical role in the process of sepsis-associated acute kidney injury through various mechanisms. Epigenetic regulation modulates the content and function of nucleic acids and proteins within cells through various modifications. Its impact on ferroptosis has garnered increasing attention; however, the role of epigenetic regulation targeting ferroptosis in sepsis-associated acute kidney injury has not been fully elucidated. Growing evidence suggests that epigenetic regulation can modulate ferroptosis through complex pathway networks, thereby affecting the development and prognosis of sepsis-associated acute kidney injury. This paper summarizes the impact of ferroptosis on sepsis-associated acute kidney injury and the regulatory mechanisms of epigenetic regulation on ferroptosis, providing new insights for the targeted therapy of sepsis-associated acute kidney injury.

Metabolic reprogramming shapes post-translational modification in macrophages

Polarized macrophages undergo metabolic reprogramming, as well as extensive epigenetic and post-translational modifications (PTMs) switch. Metabolic remodeling and dynamic changes of PTMs lead to timely macrophage response to infection or antigenic stimulation, as well as its transition from a pro-inflammatory to a reparative phenotype. The transformation of metabolites in the microenvironment also determines the PTMs of macrophages. Here we reviewed the current understanding of the altered metabolites of glucose, lipids and amino acids in macrophages shape signaling and metabolism pathway during macrophage polarization via PTMs, and how these metabolites in some macrophage-associated diseases affect disease progression by shaping macrophage PTMs.

Lactylation in CNS disorders: mechanisms, cellular function, and disease relevance

Lactate, as a metabolic product or energy substrate, participates in various neurological processes within the physiological and pathological frameworks of the central nervous system (CNS). The groundbreaking application of multi-omics integration technologies has unveiled a novel role for lactate: lactylation, a unique post-translational modification (PTM) that covalently attaches lactate groups to lysine residues on proteins. This process precisely regulates protein function and gene expression, profoundly influencing the progression of various diseases. The lactylation process is meticulously regulated by a variety of key enzymes and metabolic pathways, forming a dynamic and intricate modification network. In this review, we summarize the key enzymes involved in lactylation, specifically "Writers," "Erasers," and "Readers." Furthermore, we systematically categorize lactylation observed in various cell types within the CNS and investigate its multifaceted roles in pathological processes, including neurodegenerative diseases, brain tumors, and brain injuries. By consolidating the latest research findings in this field, our review aims to highlight the significance of these discoveries for future research and explore their potential for translational applications.

Heterogeneity of Neutrophils and Immunological Function in Neonatal Sepsis: Analysis of Molecular Subtypes Based on Hypoxia-Glycolysis-Lactylation

Objective: Hypoxia-glycolysis-lactylation (HGL) may play a crucial role in neonatal sepsis (NS). This study aims to identify HGL marker genes in NS and explore immune microenvironment among NS subtypes. Materials and Methods: The gene expression dataset GSE69686, comprising 64 NS cases and 85 controls, was selected for analysis. Based on the screened HGL-related marker genes, diagnostic prediction models were constructed using nine machine learning algorithms, and molecular subtypes of NS were identified through consensus clustering. Subsequently, the heterogeneity of biological functions and immune cell infiltration among the different subtypes was analyzed. Finally, the marker genes and lactylation were validated using the GSE25504 dataset, clinical samples, and mouse neutrophil, respectively. Results: MERTK, HK3, PGK1, and STAT3 were identified and validated as marker genes, and the diagnostic prediction model for NS constructed using the support vector machine (SVM) algorithm exhibited optimal predictive performance. Based on gene expression patterns, two distinct NS subtypes were identified. Functional enrichment analysis highlighted significant immune-related pathways, while immune infiltration analysis revealed differences in neutrophil proportions between the subtypes. Furthermore, the expression levels of marker genes were positively correlated with neutrophil infiltration. Importantly, the experimental validation results were consistent with the findings from the bioinformatics analysis. Conclusion: This study identified the distinct NS subtypes and their associated marker genes. These findings will contribute to elucidating the disease's heterogeneity and establishing appropriate personalized therapeutic approaches.

Pyruvate Kinase M1/2 Proteoformics for Accurate Insights into Energy Metabolism Abnormity to Promote the Overall Management of Ovarian Cancer Towards Predictive, Preventive, and Personalized Medicine Approaches

Ovarian cancer (OC) is a global health problem that frequently presents at advanced stages, is predisposed to recurrence, readily develops resistance to platinum-based drugs, and has a low survival rate. Predictive, preventive, and personalized medicine (PPPM/3PM) offers an integrated solution with the use of genetic, proteomic, and metabolic biomarkers to identify high-risk individuals for early detection. Metabolic reprogramming is one of the key strategies employed by tumor cells to adapt to the microenvironment and support unlimited proliferation. Pyruvate kinases M1 and M2 (PKM1/2) are encoded by the PKM gene, a pivotal enzyme in the last step of the glycolytic pathway, which is at the crossroads of aerobic oxidation and the Warburg effect to serve as a potential regulator of glucose metabolism and influence cellular energy production and metabolic reprogramming. Commonly, the ratio of PKM1-to-PKM2 is changed in tumors compared to normal controls, and PKM2 is highly expressed in OC to induce a high glycolysis rate and participate in the malignant invasion and metastatic characteristics of cancer cells with epithelial/mesenchymal transition (EMT). PKM2 inhibitors suppress the migration and growth of OC cells by interfering with the Warburg effect. Proteoforms are the final structural and functional forms of a gene/protein, and the canonical protein PKM contains all proteoforms encoded by the same PKM gene. The complexity of PKM can be elucidated by proteoformics. The OC-specific PKM proteoform might represent a specific target for therapeutic interventions against OC. In the framework of PPPM/3PM, the OC-specific PKM proteoform might be the early warning and prognosis biomarker. It is important to clarify the molecular mechanisms of PKM proteoforms in cancer metabolism. This review analyzes the expression, function, and molecular mechanisms of PKM proteoforms in OC, which help identify specific biomarkers for OC.

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.

N6-methyladenosine modification of 3'tRF-AlaAGC impairs PD-1 blockade efficacy by promoting lactic acid accumulation in the tumor microenvironment of gastric carcinoma

The balance between CD8+ T cells and regulatory T (Treg) cells in the tumor microenvironment (TME) plays a crucial role in the immune checkpoint inhibition (ICI) therapy in gastric carcinoma (GC). However, related factors leading to the disturbance of TME and resistance to ICI therapy remain unknown. In this study, we applied N6-methyladenosine (m6A) small RNA Epitranscriptomic Microarray and screened out 3'tRF-AlaAGC based on its highest differential expression level and lowest inter-group variance. N6-methyladenosine modification significantly enhanced the stability of 3'tRF-AlaAGC, which strengthened glycolysis and lactic acid (LA) production in GC cells by binding to PTBP1 (Polypyrimidine Tract Binding Protein 1). In the peritoneal GC implantation model established in huPBMC-NCG mice, 3'tRF-AlaAGC significantly increased the proportion of PD1+ Treg cells. Furthermore, in high-LA environments driven by glucose consumption of GC cells, Treg cells actively uptake LA through MCT1, facilitating NFAT1 translocation into the nucleus and enhancing PD1 expression, whereas PD1 expression by effector T cell is diminished. Meanwhile, T cell suppression assays were performed under low-LA or high-LA conditions, and the proliferation of CD8+ T cells was dampened by adding Sintilimab in a high-LA but not in a low-LA environment, suggesting the preferential activation of PD1+ Treg cell. These findings deciphered the complexities of the immune microenvironment in GC, providing prospects for identifying robust biomarkers that could improve the evaluation of therapeutic effectiveness and prognosis in immune therapy for GC.

Highly expressed VGLL3 in keloid fibroblasts promotes glycolysis and collagen production via the activation of Wnt/β-catenin signaling

PURPOSE

This study investigated the effects and related mechanisms of Vestigial-like family member 3 (VGLL3) on keloid fibroblast (KF) proliferation, apoptosis, collagen production, and glycolysis.

METHODS

Western blot, qRT-PCR, and immunohistochemistry were used for determining VGLL3 expression. KF viability, proliferation, and apoptosis were assessed using CCK-8 assay, EdU assay, and flow cytometry. Changes in the protein expression levels of α-SMA, fibronectin, collagen I, and collagen III were examined utilizing western blotting. The pathways related to VGLL3 were analyzed using Gene Set Enrichment Analysis. Changes in glycolysis were assessed by measuring oxygen consumption rate (OCR), extracellular acidification rate (ECAR), glucose uptake, and lactate production. WNT2 and β-catenin protein levels were measured using western blotting.

RESULTS

VGLL3 was upregulated in human keloid tissues. In KFs, overexpression of VGLL3 inhibited cell apoptosis, promoted cell proliferation and protein expression of α-SMA, fibronectin, collagen I, and collagen III. Moreover, it reduced OCR level, and increased the levels of ECAR, glucose uptake, and lactate production. On the other hand, the knockdown of VGLL3 had the opposite effect. WNT2 and β-catenin protein levels were enhanced by overexpression of VGLL3 and reduced by VGLL3 knockdown. Silencing of WNT2 reversed the effects of VGLL3 on apoptosis, proliferation, collagen production, and glycolysis in KFs.

CONCLUSIONS

VGLL3 promoted glycolysis in KFs and keloid progression, which was achieved through the activation of Wnt signaling pathway. Therefore, targeting VGLL3 may be a promising therapeutic strategy for the treatment of keloids.

Sepsis subphenotypes: bridging the gaps in sepsis treatment strategies

Sepsis, a heterogeneous illness produced by a dysregulated host response to infection, remains a severe mortality risk. Recent discoveries in sepsis research have stressed phenotyping as a feasible strategy for tackling heterogeneity and enhancing therapy precision. Sepsis phenotyping has moved from traditional stratifications based on severity and prognosis to dynamic, phenotype-driven therapeutic options. This review covers recent progress in connecting sepsis subgroups to personalized treatments, with a focus on phenotype-based therapeutic predictions and decision-support systems. Despite ongoing challenges, such as standardizing phenotyping frameworks and incorporating findings into clinical practice, this topic has enormous promise. By investigating phenotypic variation in therapy responses, we hope to uncover new biomarkers and phenotype-driven therapeutic solutions, laying the groundwork for more effective therapies and, ultimately improving patient outcomes.

[Mechanism of WAVE1 regulation of lipopolysaccharide-induced mitochondrial metabolic abnormalities and inflammatory responses in macrophages]

OBJECTIVES

To explore the mechanism by which Wiskott-Aldrich syndrome protein family verprolin-homologous protein 1 (WAVE1) regulates lipopolysaccharide (LPS)-induced mitochondrial metabolic abnormalities and inflammatory responses in macrophages.

METHODS

Macrophage cell lines with overexpressed WAVE1 (mouse BMDM and human THP1 cells) were prepared. The macrophages were treated with LPS (500 ng/mL) to simulate sepsis-induced inflammatory responses. The experiment consisted of two parts. The first part included control, LPS, vector (LPS+oe-NC), WAVE1 overexpression (LPS+oe-WAVE1) groups. The second part included LPS, LPS+oe-NC, LPS+oe-WAVE1 and exogenous high mobility group box-1 (HMGB1) intervention (LPS+oe-WAVE1+HMGB1) groups. RT-PCR was used to measure mitochondrial DNA content, and RT-qPCR was used to detect the mRNA expression levels of WAVE1, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. Western blot was performed to measure the protein expression of WAVE1, hexokinase 2, and pyruvate kinase M2. ELISA was utilized to detect the levels of TNF-α, IL-1β, IL-6, and HMGB1. JC-1 staining was used to assess mitochondrial membrane potential. Seahorse XP96 was used to evaluate oxygen consumption rate and extracellular acidification rate. MitoSOX probe was employed to measure mitochondrial reactive oxygen species levels, and 2-NBDG method was used to assess glucose uptake. Kits were used to measure pyruvate kinase activity, lactate, adenosine triphosphate (ATP), and HMGB1 levels.

RESULTS

Compared with the control group, the LPS group showed lower levels of WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expression levels as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were significantly increased (P<0.05). Compared with the LPS+oe-NC group, the LPS+oe-WAVE1 group showed increased WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expressions, as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were decreased (P<0.05). Compared with the LPS+oe-WAVE1 group, the LPS+oe-WAVE1+HMGB1 group exhibited increased glucose uptake, lactate, ATP levels, and extracellular acidification rate (P<0.05).

CONCLUSIONS

WAVE1 participates in the regulation of LPS-induced inflammatory responses in macrophages by modulating the release of inflammatory factors, mitochondrial metabolism, and HMGB1 release.

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.

Mitochondrial dysfunction in acute kidney injury

Acute kidney injury (AKI) is a systemic clinical syndrome increasing morbidity and mortality worldwide in recent years. Renal tubular epithelial cells (TECs) death caused by mitochondrial dysfunction is one of the pathogeneses. The imbalance of mitochondrial quality control is the main cause of mitochondrial dysfunction. Mitochondrial quality control plays a crucial role in AKI. Mitochondrial quality control mechanisms are involved in regulating mitochondrial integrity and function, including antioxidant defense, mitochondrial quality control, mitochondrial DNA (mtDNA) repair, mitochondrial dynamics, mitophagy, and mitochondrial biogenesis. Currently, many studies have used mitochondrial dysfunction as a targeted therapeutic strategy for AKI. Therefore, this review aims to present the latest research advancements on mitochondrial dysfunction in AKI, providing a valuable reference and theoretical foundation for clinical prevention and treatment of this condition, ultimately enhancing patient prognosis.

EP300-mediated H3 acetylation elevates MTHFD2 expression to reduce mitochondrial dysfunction in lipopolysaccharide-induced tubular epithelial cells

Sepsis represents an organ dysfunction resulting from the host's maladjusted response to infection, and can give rise to acute kidney injury (AKI), which significantly increase the morbidity and mortality of septic patients. This study strived for identifying a novel therapeutic strategy for patients with sepsis-induced AKI (SI-AKI). Rat tubular epithelial NRK-52E cells were subjected to lipopolysaccharide (LPS) exposure for induction of in-vitro SI-AKI. The expressions of E1A binding protein p300 (EP300) and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) in NRK-52E cells were assessed by western blot and qRT-PCR, and their interaction was explored by chromatin immunoprecipitation performed with antibody for H3K27 acetylation (H3K27ac). The effect of them on SI-AKI-associated mitochondrial dysfunction of tubular epithelial cells was investigated using transfection, MTT assay, TUNEL staining, 2',7'-Dichlorodihydrofluorescein diacetate probe assay, Mitosox assay, and JC-1 staining. MTHFD2 and EP300 were upregulated by LPS exposure in NRK-52E cells. LPS increased the acetylation of H3 histone in the MTHFD2 promoter region, and EP300 suppressed the effect of LPS. EP300 ablation inhibited the expression of MTHFD2. MTHFD2 overexpression antagonized LPS-induced viability reduction, apoptosis promotion, reactive oxygen species overproduction, and mitochondrial membrane potential collapse of NRK-52E cells. By contrast, MTHFD2 knockdown and EP300 ablation brought about opposite consequences. Furthermore, MTHFD2 overexpress and EP300 ablation counteracted each other's effect in LPS-exposed NRK-52E cells. EP300-mediated H3 acetylation elevates MTHFD2 expression to reduce mitochondrial dysfunction of tubular epithelial cells in SI-AKI.

Extracellular NCOA4 is a mediator of septic death by activating the AGER-NFKB pathway

Sepsis, a life-threatening condition resulting from a dysregulated response to pathogen infection, poses a significant challenge in clinical management. Here, we report a novel role for the autophagy receptor NCOA4 in the pathogenesis of sepsis. Activated macrophages and monocytes secrete NCOA4, which acts as a mediator of septic death in mice. Mechanistically, lipopolysaccharide, a major component of the outer membrane of Gram-negative bacteria, induces NCOA4 secretion through autophagy-dependent lysosomal exocytosis mediated by ATG5 and MCOLN1. Moreover, bacterial infection with E. coli or S. enterica leads to passive release of NCOA4 during GSDMD-mediated pyroptosis. Upon release, extracellular NCOA4 triggers the activation of the proinflammatory transcription factor NFKB/NF-κB by promoting the degradation of NFKBIA/IκB molecules. This process is dependent on the pattern recognition receptor AGER, rather than TLR4. In vivo studies employing endotoxemia and polymicrobial sepsis mouse models reveal that a monoclonal neutralizing antibody targeting NCOA4 or AGER delays animal death, protects against organ damage, and attenuates systemic inflammation. Furthermore, elevated plasma NCOA4 levels in septic patients, particularly in non-survivors, correlate positively with the sequential organ failure assessment score and concentrations of lactate and proinflammatory mediators, such as TNF, IL1B, IL6, and HMGB1. These findings demonstrate a previously unrecognized role of extracellular NCOA4 in inflammation, suggesting it as a potential therapeutic target for severe infectious diseases. Abbreviation: BMDMs: bone marrow-derived macrophages; BUN: blood urea nitrogen; CLP: cecal ligation and puncture; ELISA: enzyme-linked immunosorbent assay; LPS: lipopolysaccharide; NO: nitric oxide; SOFA: sequential organ failure assessment.

Treponema Pallidum protein Tp47 triggers macrophage inflammatory senescence via PKM2-mediated metabolic reprogramming

Syphilis is a sexually transmitted disease caused by Treponema pallidum. The mechanisms enabling T. pallidum to persist despite macrophage eradication efforts in syphilis remain unclear. Pathogens can exploit senescent cells to enhance host susceptibility, and cellular senescence can be induced by pyroptosis, which known as inflammatory senescence. While recent studies have linked metabolic reprogramming to inflammatory senescence, their role in syphilis remained to be clarified. This study investigated the mechanisms of Tp47 on metabolic reprogramming and inflammatory senescence in macrophages. The results demonstrated that Tp47 triggered NLRP3 inflammasome-mediated pyroptosis by activating the phosphorylation of EIF2AK2 (a protein kinase), increasing senescence-associated pro-inflammatory cytokines secretion and leading to inflammatory senescence in macrophages. Additionally, Tp47 competitively bound to pyruvate kinase M2 (PKM2) with STUB1(a ubiquitin ligase), thereby inhibiting PKM2 ubiquitination degradation. By promoting the Y105 phosphorylation of PKM2, Tp47 modulated the intracellular function of PKM2, and facilitated PKM2-mediated metabolic reprogramming, which produced lactate that subsequently led to EIF2AK2 phosphorylation. Furthermore, inhibitors targeting EIF2AK2, lactate, glycolysis, and PKM2 effectively suppressed the inflammatory senescence induced by Tp47. In conclusion, Tp47 could mediate immune metabolic reprogramming through interaction with PKM2 to trigger macrophage inflammatory senescence. These discoveries offer a novel perspective for targeted therapies against syphilis.

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.

Shikonin ameliorated LPS-induced acute lung injury in mice via modulating MCU-mediated mitochondrial Ca2+ and macrophage polarization

BACKGROUND

Macrophages play a pivotal role in the development and recovery of acute lung injury (ALI), wherein their phenotypic differentiation and metabolic programming are orchestrated by mitochondria. Specifically, the mitochondrial calcium uniporter (MCU) regulates mitochondrial Ca2+ (mCa2+) uptake and may bridge the metabolic reprogramming and functional regulation of immune cells. However, the precise mechanism on macrophages remains elusive. Shikonin, a natural naphthoquinone, has demonstrated efficacy in mitigating ALI and suppressing glycolysis in macrophages, yet which mechanism remains to be fully elucidated.

PURPOSE

This study explored whether Shikonin ameliorated ALI via modulating MCU-mediated mCa2+ and macrophage polarization.

METHODS

This study firstly examined the protective effects of Shikonin on LPS-induced ALI mice, and investigated whether it is depends on macrophage by depleting macrophage using clodronate liposomes. The regulatory effect of Shikonin on macrophage polarization and mitochondrial MCU/Ca2+ signal was testified on RAW264.7 cells, and further validated by knocking-down MCU expression or by using RU360, an MCU inhibitor. Additionally, the crucial role of MCU in the therapeutic effect of Shikonin, along with its regulation on macrophage polarization was validated in mice with LPS-induced ALI under the intervention of RU360.

RESULTS

Shikonin alleviated LPS-induced mice ALI, down-regulated inflammatory cytokines and inhibited the pro-inflammatory polarization of macrophages. Intravenous injection of clodronate liposomes on mice abolished the protective effects of Shikonin on ALI. On RAW264.7 cells, LPS&IFN decreased the protein expression of MCU, while induced pro-inflammatory polarization and glycolytic metabolism. In contrast, Shikonin increased MCU expression, activated MCU-mediated mCa2+ signal, promoted the polarization of macrophages to anti-inflammatory M2 phenotype, and driven a metabolic shift from glycolysis to oxidative phosphorylation. Either knocking-down MCU expression or pharmacological inhibiting MCU by using RU360 mitigated the effects of Shikonin on Raw 264.7 cells. Furthermore, RU360 counteracted the ameliorative effect of Shikonin on ALI mice.

CONCLUSION

The current data showed that Shikonin alleviated LPS-induced mice ALI by activating mitochondrial MCU/mCa2+ signal and regulating macrophage metabolism.

Crosstalk between lactate and tumor-associated immune cells: clinical relevance and insight

Lactate, which was traditionally viewed as a metabolic byproduct of anaerobic glycolysis, has emerged as a significant signaling molecule involved in the development of tumors. Current studies highlight its dual function, where it not only fuels tumor development but also modulates immune responses. Lactate has an effect on various tumor-associated immune cells, promoting immunosuppressive conditions that facilitate tumor growth and immune evasion. This phenomenon is strongly associated with the Warburg effect, a metabolic shift observed in many cancers that favors glycolysis over oxidative phosphorylation, resulting in elevated lactate production. Exploring the complex interplay between lactate metabolism and tumor immunity provides a novel understanding regarding the mechanisms of tumor immune evasion and resistance to therapies. This review discusses the unique biology of lactate in the TME, its impact on immune cell dynamics, and its potential as a tumor treatment target.

Metabolic Crossroad Between Macrophages and Cancer Cells: Overview of Hepatocellular Carcinoma

The metabolic interplay between macrophages and cancer cells mirrors the plasticity of both kinds of cells, which adapt to the microenvironment by sustaining cell growth and proliferation. In this way, cancer cells induce macrophage polarization, and, on the other hand, tumor-associated macrophages (TAMs) contribute to the survival of cancer cells. In a simplified manner, macrophages can assume two opposite subtypes: M1, pro-inflammatory and anti-tumor phenotype, and M2, anti-inflammatory and protumor phenotype. How do cancer cells induce macrophage polarization? Any actor involved in tumor growth, including the mitochondria, releases molecules into the tumor microenvironment (TME) that trigger a subtype transition. These metabolic changes are the primary cause of this polarization. Hepatocellular carcinoma (HCC), the prevalent type of liver primary tumor, is characterized by cells with extensive metabolic adaptions due to high flexibility in different environmental conditions. This review focuses on the main metabolic features of M1 and M2 macrophages and HCC cells underlying their metabolic behavior in response to TME.

CITED2 Mediates Metabolic Reprogramming in Renal Tubular Epithelial Cells via the AKT Signaling Pathway to Induce Sepsis-Associated Acute Kidney Injury

Background

Sepsis-associated acute kidney injury (S-AKI) is a prevalent and severe clinical complication in intensive care units (ICUs) and is associated with high mortality and poor prognosis. The dysfunction of renal tubular epithelial cells (TECs), particularly through their metabolic reprogramming, plays a critical role in the onset and progression of S-AKI. CITED2 is shown to regulate a variety of cellular processes, but its specific impact on TECs metabolism and S-AKI pathogenesis remains unclear. The aim of this study was to investigate the role of CITED2 in the metabolic reprogramming of TECs and its effects on inflammation and kidney injury in S-AKI.

Material and Methods

The C57BL/6 mouse model of S-AKI was established using cecal ligation and puncture (CLP). We assessed the inflammatory responses, glucose metabolism and CITED2 expression in the kidneys of septic mice. Additionally, the effect of CITED2 on TECs metabolism and inflammation was evaluated using in vivo and in vitro models. CITED2 silencing and overexpression were employed to elucidate its regulatory role, focusing on the AKT signaling pathway.

Results

S-AKI causes structural and functional kidney damage, aggravated inflammatory responses, and dysregulated glucose metabolism, accompanied by increased expression of CITED2. CITED2 silencing attenuated TECs metabolic dysfunction and reduced inflammation, thereby protecting the kidney from injury. Conversely, CITED2 overexpression exacerbated TECs metabolic dysfunction, promoted inflammatory responses, and worsened kidney injury. Mechanistically, CITED2 regulates TEC metabolism through the AKT signaling pathway, promoting S-AKI-related inflammation and contributing to kidney injury.

Conclusion

CITED2 drives the metabolic reprogramming of TECs through the AKT signaling pathway, thereby aggravating the inflammatory response and leading to kidney injury, highlighting its critical role in S-AKI. Targeting CITED2 inhibition may represent a novel therapeutic approach for managing S-AKI.

rTM reprograms macrophages via the HIF-1α/METTL3/PFKM axis to protect mice against sepsis

The metabolic reprogramming of macrophages is a potential therapeutic strategy for sepsis treatment, but the mechanism underlying this reprogramming remains unclear. Since glycolysis can drive macrophage phenotype switching, the rate-limiting enzymes in glycolysis may be key to treating sepsis. Here, we found that, compared with other isoenzymes, the expression of 6-phosphofructokinase, muscle type (PFKM) was the most upregulated in monocytes from septic patients. Recombinant thrombomodulin (rTM) treatment downregulated the protein expression of PFKM in macrophages. Both rTM treatment and Pfkm knockout protected mice from sepsis and reduced the production of the proinflammatory cytokines IL-1β, IL-6, TNF-α, and IL-27, whereas PFKM overexpression increased the production of these cytokines. Mechanistically, rTM treatment inhibited glycolysis in macrophages by decreasing PFKM expression in a hypoxia-inducible factor-1α (HIF-1α)-dependent manner. HIF-1α overexpression increased methyltransferase-like 3 (METTL3) expression, elevated the m6A level on Pfkm, and upregulated the protein expression of PFKM. METTL3 silence attenuated HIF-1α-mediated PFKM expression. These findings provide insight into the underlying mechanism of macrophage reprogramming for the treatment of sepsis.

Acute hyperglycemia exacerbates neuroinflammation and cognitive impairment in sepsis-associated encephalopathy by mediating the ChREBP/HIF-1α pathway

OBJECTIVES

Delirium is a prominent symptom of sepsis-associated encephalopathy (SAE) and is highly prevalent in septic patients hospitalized in the intensive care unit, being closely connected with raised mortality rates. Acute hyperglycemia (AH) has been recognized as a separate risk factor for delirium and a worse prognosis in critically sick patients. Nevertheless, the exact contribution of AH to the advancement of SAE is still unknown.

METHODS

This research retrospectively evaluated the connection between blood glucose levels (BGLs) and the incidence of delirium and death rates in septic patients in the ICU of a tertiary comprehensive hospital. In addition, a septic rat model was induced through cecal ligation and puncture (CLP), after which continuous glucose infusion was promptly initiated via a central venous catheter post-surgery to evaluate the potential implications of AH on SAE. Next, septic rats were assigned to four groups based on target BGLs: high glucose group (HG, ≥ 300 mg/dL), moderate glucose group (MG, 200-300 mg/dL), normal glucose group (NG, < 200 mg/dL), and a high glucose insulin-treated group (HI, 200-300 mg/dL) receiving recombinant human insulin treatment (0.1 IU/kg/min). The sham group (SG) received an equivalent volume of saline infusion and denoted the NG group. The effects of AH on neuroinflammation and cognitive function in septic rats were evaluated using behavioral tests, histopathological examination, TUNEL staining, ELISA, and Western blot. The effects of glucose levels on microglial activation and glucose metabolism following lipopolysaccharide (LPS, 1 μg/mL) exposure were assessed using CCK8 assay, qRT-PCR, Western blot, and ELISA.

RESULTS

Our findings revealed that AH during sepsis was a separate risk factor for delirium and assisted in predicting delirium occurrence. AH raised the levels of systemic and central inflammatory cytokines in septic rats, promoting neuronal apoptosis, blood-brain barrier disruption, and cognitive impairment. In addition, both in vivo and in vitro, an elevated glucose challenge increased the ChREBP, HIF-1α, glycolytic enzymes, and inflammatory cytokines expressions in microglia after exposure to CLP or LPS.

CONCLUSIONS

These results collectively suggest that hyperglycemia can exacerbate neuroinflammation and delirium by enhancing microglial glycolysis under septic conditions, potentially mediated by upregulation of the ChREBP/HIF-1α signaling pathway.

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.

Sepsis-induced changes in pyruvate metabolism: insights and potential therapeutic approaches

Sepsis is a heterogeneous syndrome resulting from a dysregulated host response to infection. It is considered as a global major health priority. Sepsis is characterized by significant metabolic perturbations, leading to increased circulating metabolites such as lactate. In mammals, pyruvate is the primary substrate for lactate production. It plays a critical role in metabolism by linking glycolysis, where it is produced, with the mitochondrial oxidative phosphorylation pathway, where it is oxidized. Here, we provide an overview of all cytosolic and mitochondrial enzymes involved in pyruvate metabolism and how their activities are disrupted in sepsis. Based on the available data, we also discuss potential therapeutic strategies targeting these pyruvate-related enzymes leading to enhanced survival.

CHAC1 blockade suppresses progression of lung adenocarcinoma by interfering with glucose metabolism via hijacking PKM2 nuclear translocation

Patients with lung adenocarcinoma (LUAD) generally have poor prognosis. Abnormal cellular energy metabolism is a hallmark of LUAD. Glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) is a member of the γ-glutamylcyclotransferase family and an unfolded protein response pathway regulatory gene. Its biological function and molecular regulatory mechanism, especially regarding energy metabolism underlying LUAD, remain unclear. By utilizing tissue microarray and data from The Cancer Genome Atlas and Gene Expression Omnibus, we found that CHAC1 expression was markedly higher in LUAD tissues than in non-tumor tissues, and was positively correlated with poor prognosis. Phenotypically, CHAC1 overexpression enhanced the proliferation, migration, invasion, tumor sphere formation, and glycolysis ability of LUAD cells, resulting in tumor growth both in vitro and in vivo. Mechanistically, through a shotgun mass spectrometry-based proteomic approach and high-throughput RNA sequencing, we found that CHAC1 acted as a bridge connecting UBA2 and PKM2, enhancing the SUMOylation of PKM2. The SUMOylated PKM2 then transferred from the cytoplasm to the nucleus, activating the expression of glycolysis-related genes and enhancing the Warburg effect. Lastly, E2F Transcription Factor 1 potently activated CHAC1 transcription by directly binding to the CHAC1 promoter in LUAD cells. The results of this study implied that CHAC1 regulates energy metabolism and promotes glycolysis in LUAD progression.

Intermittent hyperglycaemia induces macrophage dysfunction by extracellular regulated protein kinase-dependent PKM2 translocation in periodontitis

Early fluctuations in blood glucose levels increased susceptibility to macrophage dysfunction. However, the underlying pathological mechanisms linking glucose variations and macrophage dysregulation remains elusive. In current study, we established an animal model of transient intermittent hyperglycaemia (TIH) to simulate early fluctuations in blood glucose levels. Our findings revealed that both TIH and diabetic group exhibited more severe periodontal lesions and increased secretion of pro-inflammatory cytokines compared to healthy controls. In immortalized bone marrow-derived macrophages (iBMDMs), phagocytosis and chemotaxis were impaired with transient and lasting hyperglycaemia, accompanied by enhanced glycolysis. We also found that TIH activated pyruvate kinase M2 (PKM2) through the phosphorylation of extracellular regulated protein kinase (ERK) in vivo, particularly at dimeric levels. In macrophage cultured with TIH, PKM2 translocated into the nucleus and involved in the regulating inflammatory genes, including TNF-α, IL-6 and IL-1β. PKM2 translocation and secretion of inflammatory cytokines were attenuated by PD98059, while PKM2 tetramer activator TEPP-46 prevented the formation of dimeric PKM2 in macrophages. Moreover, inhibition of glycolysis alleviated the TIH-induced pro-inflammatory cytokines. In conclusion, our manuscript provides a rationale for understanding how TIH modulates metabolic rewiring and dysfunction in macrophages via ERK-dependent PKM2 nuclear translocation.

Exploring the mechanism of action of Chinese medicine in regulating liver fibrosis based on the alteration of glucose metabolic pathways

In recent years, metabolic reprogramming in liver fibrosis has become a research hotspot in the field of liver fibrosis at home and abroad. Liver fibrosis is a pathological change caused by chronic liver injury from a variety of causes. Liver fibrosis is a common pathological feature of many chronic liver diseases such as chronic hepatitis B, non-alcoholic steatohepatitis, and autoimmune hepatitis, as well as the pathogenesis of the disease. The development of chronic liver disease into cirrhosis must go through the pathological process of liver fibrosis, in which hepatic stellate cells (HSC) play an important role. Following liver injury, HSC are activated and transdifferentiated into scar-forming myofibroblasts, which drive the trauma healing response and which rely on the deposition of collagen-rich extracellular matrix to maintain tissue integrity. This reaction will continue without strict control, which will lead to excessive accumulation of matrix and liver fibrosis. The mechanisms and clinical studies of liver fibrosis have been the focus of research in liver diseases. In recent years, several studies have revealed the mechanism of HSC metabolic reprogramming and the impact of this process on liver fibrosis, in which glucose metabolic reprogramming plays an important role in the activation of HSC, and it mainly meets the energy demand of HSC activation by upregulating glycolysis. Glycolysis is the process by which one molecule of glucose is broken down into two molecules of pyruvate and produces energy and lactate under anaerobic conditions. Various factors have been found to be involved in regulating the glycolytic process of HSC, including glucose transport, intracellular processing of glucose, exosome secretion, and lactate production, etc. Inhibition of the glycolytic process of HSC can be an effective strategy against liver fibrosis. Currently, the combined action of multiple targets and links of Chinese medicine such as turmeric, comfrey, rhubarb and scutellaria baicalensis against the mechanism of liver fibrosis can effectively improve or even reverse liver fibrosis. This paper summarizes that turmeric extract curcumin, comfrey extract comfreyin, rhubarb, Subtle yang yu yin granules, Scutellaria baicalensis extract oroxylin A and cardamom extract cardamomin affect liver fibrosis by regulating gluconeogenic reprogramming. Therefore, studying the mechanism of action of TCM in regulating liver fibrosis through reprogramming of glucose metabolism is promising to explore new methods and approaches for Chinese Medicine modernization research.

Utility of Lactate Levels in the Diagnosis and Prognosis of Septic Shock

ABSTRACT

Early recognition of septic shock and its treatment are key factors for limiting progression to multiple organ dysfunction and death. Lactate, a byproduct of metabolic pathways, is usually elevated in tissue hypoperfusion and shock and is associated with poor prognosis in sepsis. As a biomarker, it may help the clinician in risk stratification, and the identification and treatment of sepsis. In this article, we provide an update on lactate's pathophysiology and role in diagnosis, treatment, and prognosis in children with sepsis and septic shock.

Role of pyruvate kinase M2 in regulating sepsis (Review)

Glycolysis occurs in all living organisms as a form of energy supply. Pyruvate kinase M2 (PKM2) is one of the rate‑limiting enzymes in the glycolytic process. PKM2 is considered to serve an important role in several terminal diseases, including sepsis. However, to the best of our knowledge, the specific mechanistic role of PKM2 in sepsis remains to be systematically summarised. Therefore, the present review aims to summarise the roles of PKM2 in sepsis progression. In addition, potential treatment strategies for patients with sepsis are discussed. The present review hopes to lay the groundwork for studying the role of PKM2 and developing therapeutic strategies against metabolic disorders that occur during sepsis.

A New Strategy for Targeting UCP2 to Modulate Glycolytic Reprogramming as a Treatment for Sepsis A New Strategy for Targeting UCP2

Sepsis is a severe and life-threatening disease caused by infection, characterized by a dysregulated immune response. Unfortunately, effective treatment strategies for sepsis are still lacking. The intricate interplay between metabolism and the immune system limits the treatment options for sepsis. During sepsis, there is a profound shift in cellular energy metabolism, which triggers a metabolic reprogramming of immune cells. This metabolic alteration impairs immune responses, giving rise to excessive inflammation and immune suppression. Recent research has demonstrated that UCP2 not only serves as a critical target in sepsis but also functions as a key metabolic switch involved in immune cell-mediated inflammatory responses. However, the regulatory mechanisms underlying this modulation are complex. This article focuses on UCP2 as a target and discusses metabolic reprogramming during sepsis and the complex regulatory mechanisms between different stages of inflammation. Our research indicates that overexpression of UCP2 reduces the Warburg effect, restores mitochondrial function, and improves the prognosis of sepsis. This discovery aims to provide a promising approach to address the significant challenges associated with metabolic dysfunction and immune paralysis.

The Values of PDK1 and LDH Levels in Patients with Sepsis and Septic Shock: A Prospective Observational Study

Background

Metabolic changing is the significant host stress response during sepsis, but there is increasing evidence that uncontrolled metabolic reprogramming is a contributing factor to sepsis. Nevertheless, its association with outcome in patients with sepsis has been poorly investigated. As the key enzyme of metabolic reprogramming, the clinical value of PDK1 and LDH in patients with sepsis will be investigated in this study.

Methods

We collected serum from 167 ICU patients within 24 hours of admission for a single-center prospective observational study. The levels of PDK1 and LDH were detected by enzyme-linked adsorption method. Pearson or Spearman coefficient for correlation analysis between PDK1, LDH and clinical indicators. Areas under the ROC curves for evaluation of mortality prediction. Kaplan-Meier survival curve analysis was performed, and Cox proportional hazards model was performed to determine the risk factors for 28-day mortality.

Results

The PDK1/LDH in the septic shock group was statistically different between both the sepsis group and ICU control group, and had good correlation with ScvO2 and lactate. In predicting 28-day mortality in patients with sepsis, the best AUC was observed for PDK1/LDH, and was higher than the AUC for PDK1, lactate, and SOFA. Additionally, patients with lower PDK1/LDH had markerablely higher 28-day mortality. The multivariate Cox proportional hazards model revealed that PDK1/LDH < 0.1808 were the independent risk factors for 28-day mortality in sepsis.

Conclusion

The level of PDK1/LDH at admission was markedly decreased in patients with septic shock, which can serve as a novel independent prognostic biomarker for predicting mortality.

Lactate's impact on immune cells in sepsis: unraveling the complex interplay

Lactate significantly impacts immune cell function in sepsis and septic shock, transcending its traditional view as just a metabolic byproduct. This review summarizes the role of lactate as a biomarker and its influence on immune cell dynamics, emphasizing its critical role in modulating immune responses during sepsis. Mechanistically, key lactate transporters like MCT1, MCT4, and the receptor GPR81 are crucial in mediating these effects. HIF-1α also plays a significant role in lactate-driven immune modulation. Additionally, lactate affects immune cell function through post-translational modifications such as lactylation, acetylation, and phosphorylation, which alter enzyme activities and protein functions. These interactions between lactate and immune cells are central to understanding sepsis-associated immune dysregulation, offering insights that can guide future research and improve therapeutic strategies to enhance patient outcomes.

Neurotoxic effects of triclosan in adolescent mice: Pyruvate kinase M2 dimer regulated Signal transducer and activator of transcription 3 phosphorylation mediated microglia activation and neuroinflammation

Triclosan (TCS), a commonly used antibacterial agent, is associated with various harmful effects on mammalian neurodevelopment, particularly when exposed prenatally. This study investigated the impact of long-term exposure to TCS on the prefrontal cortex development in adolescent mice. We evaluated the motor ability, motor coordination, and anxiety behavior of mice using open field tests (OFT) and elevated cross maze tests (EPM). An increase in movement distance, number of passes through the central area, and open arm retention time was observed in mice treated with TCS. Hematoxylin eosin staining and Nissl staining also showed significant adverse reactions in the brain tissue of TCS-exposed group. TCS induced microglia activation and increased inflammatory factors expression in the prefrontal cortex. TCS also increased the expression of pyruvate kinase M2 (PKM2), thereby elevating the levels of PKM2 dimer, which entered the nucleus. Treatment with TEPP46 (PKM2 dimer nuclear translocation inhibitor) blocked the expression of inflammatory factors induced by TCS. TCS induced the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3) in vivo and in vitro, upregulating the levels of inflammatory cytokines. The results also demonstrated the binding of PKM2 to STAT3, which promoted STAT3 phosphorylation at the Tyr705 site, thereby regulating the expression of inflammatory factors. These findings highlight the role of PKM2-regulated STAT3 phosphorylation in TCS-induced behavioral disorders in adolescents and propose a reliable treatment target for TCS.

α-Ketoglutarate plays an inflammatory inhibitory role by regulating scavenger receptor class a expression through N6-methyladenine methylation during sepsis

Sepsis arises from an uncontrolled inflammatory response triggered by infection or stress, accompanied by alteration in cellular energy metabolism, and a strong correlation exists between these factors. Alpha-ketoglutarate (α-KG), an intermediate product of the TCA cycle, has the potential to modulate the inflammatory response and is considered a crucial link between energy metabolism and inflammation. The scavenger receptor (SR-A5), a significant pattern recognition receptor, assumes a vital function in anti-inflammatory reactions. In the current investigation, we have successfully illustrated the ability of α-KG to mitigate inflammatory factors in the serum of septic mice and ameliorate tissue damage. Additionally, α-KG has been shown to modulate metabolic reprogramming and macrophage polarization. Moreover, our findings indicate that the regulatory influence of α-KG on sepsis is mediated through SR-A5. We also elucidated the mechanism by which α-KG regulates SR-A5 expression and found that α-KG reduced the N6-methyladenosine level of macrophages by up-regulating the m6A demethylase ALKBH5. α-KG plays a crucial role in inhibiting inflammation by regulating SR-A5 expression through m6A demethylation during sepsis. The outcomes of this research provide valuable insights into the relationship between energy metabolism and inflammation regulation, as well as the underlying molecular regulatory mechanism.

Interference with ENO2 promotes ferroptosis and inhibits glycolysis in clear cell renal cell carcinoma by regulating Hippo‑YAP1 signaling

Glycolytic enzyme enolase 2 (ENO2) is dysregulated in various cancer types. Nevertheless, the role and underlying mechanism of ENO2 in clear cell renal cell carcinoma (ccRCC) remain unclear. Therefore, the current study investigated the effect and mechanism of ENO2 in ccRCC. ENO2 expression in a ccRCC cell line was assessed using reverse transcription-quantitative PCR and western blotting. Analysis of glycolysis was performed by estimating the extracellular acidification rate, lactic acid concentration, glucose uptake and the expression of glucose transporter 1, pyruvate kinase muscle isozyme M2 and hexokinase 2. Moreover, ferroptosis was assessed by detecting the level of total iron, lipid peroxide, reactive oxygen species and the expression of ferroptosis-related protein. In addition, mitochondrial function was assessed using JC-1 staining and detection kits. The results indicated that ENO2 is expressed at high levels in ccRCC cell lines, and interference with ENO2 expression inhibits glycolysis, promotes ferroptosis and affects mitochondrial function in ccRCC cells. Further investigation demonstrated that interference with ENO2 expression affected ferroptosis levels in ccRCC cells by inhibiting the glycolysis process. Mechanistically, the present results indicated that ENO2 may affect ferroptosis, glycolysis and mitochondrial functions by regulating Hippo-yes-associated protein 1 (YAP1) signaling in ccRCC cells. In conclusion, the present study showed that ENO2 affects ferroptosis, glycolysis and mitochondrial functions in ccRCC cells by regulating Hippo-YAP1 signaling, hence demonstrating its potential as a therapeutic target in ccRCC.

Urinary PKM2, a marker predicating acute kidney injury in patients with sepsis

PURPOSE

Acute kidney injury (AKI) is a complication commonly occurred in patients with sepsis, and AKI has become the leading cause associated with mortality. PKM2, as a rate-limiting enzyme of glycolysis, was considered to be involved in AKI in vitro and animal models. However, there have been no studies reported on the expression of PKM2 in humans and its association with AKI.

METHODS

A retrospective study including 57 patients (35 males and 22 females) that were admitted into hospital in 2019 was carried out in our research. The basic characteristics and clinical parameters of each patient were collected from patients' medical records. We assessed changes in the expression of serum and urinary PKM2 using ELISA and its association with clinical manifestations in patients with sepsis through correlation analysis. Besides, ROC analysis was applied for evaluating the role of PKM2 in predicting AKI and death rate.

RESULTS

Urinary PKM2 is obviously increased in patients with sepsis-associated AKI (P < 0.05), while no significant change was found in the expression of serum PKM2. Moreover, the expression of urinary PKM2 is positively correlated with serum creatinine (r=0.577, P < 0.01) and blood-urea-nitrogen (r=0.531, P<0.01). In addition, it is negatively correlated with glomerular filtration rate (r=-0.583, P<0.01). Besides, ROC analysis indicated that urinary PKM2 could be a predictor of AKI in patients with sepsis (AUC-ROC, 0.819; SE, 0.086, P = 0.004, 95% CI 0.651-0.986).

CONCLUSIONS

Urinary PKM2 could be a marker predicting acute kidney injury in patients with sepsis.

Metabolic reprogramming in septic acute kidney injury: pathogenesis and therapeutic implications

Acute kidney injury (AKI) is a frequent and severe complication of sepsis and is characterized by significant mortality and morbidity. However, the pathogenesis of septic acute kidney injury (S-AKI) remains elusive. Metabolic reprogramming, which was originally referred to as the Warburg effect in cancer, is strongly related to S-AKI. At the onset of sepsis, both inflammatory cells and renal parenchymal cells, such as macrophages, neutrophils and renal tubular epithelial cells, undergo metabolic shifts toward aerobic glycolysis to amplify proinflammatory responses and fortify cellular resilience to septic stimuli. As the disease progresses, these cells revert to oxidative phosphorylation, thus promoting anti-inflammatory reactions and enhancing functional restoration. Alterations in mitochondrial dynamics and metabolic reprogramming are central to the energetic changes that occur during S-AKI. In this review, we summarize the current understanding of the pathogenesis of metabolic reprogramming in S-AKI, with a focus on each cell type involved. By identifying relevant key regulatory factors, we also explored potential metabolic reprogramming-related therapeutic targets for the management of S-AKI.

Metabolic Reprogramming of Astrocytes in Pathological Conditions: Implications for Neurodegenerative Diseases

Astrocytes play a pivotal role in maintaining brain energy homeostasis, supporting neuronal function through glycolysis and lipid metabolism. This review explores the metabolic intricacies of astrocytes in both physiological and pathological conditions, highlighting their adaptive plasticity and diverse functions. Under normal conditions, astrocytes modulate synaptic activity, recycle neurotransmitters, and maintain the blood-brain barrier, ensuring a balanced energy supply and protection against oxidative stress. However, in response to central nervous system pathologies such as neurotrauma, stroke, infections, and neurodegenerative diseases like Alzheimer's and Huntington's disease, astrocytes undergo significant morphological, molecular, and metabolic changes. Reactive astrocytes upregulate glycolysis and fatty acid oxidation to meet increased energy demands, which can be protective in acute settings but may exacerbate chronic inflammation and disease progression. This review emphasizes the need for advanced molecular, genetic, and physiological tools to further understand astrocyte heterogeneity and their metabolic reprogramming in disease states.

The Role of PKM2 in Multiple Signaling Pathways Related to Neurological Diseases

Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. It is well known that PKM2 plays a vital role in the proliferation of tumor cells. However, PKM2 can also exert its biological functions by mediating multiple signaling pathways in neurological diseases, such as Alzheimer's disease (AD), cognitive dysfunction, ischemic stroke, post-stroke depression, cerebral small-vessel disease, hypoxic-ischemic encephalopathy, traumatic brain injury, spinal cord injury, Parkinson's disease (PD), epilepsy, neuropathic pain, and autoimmune diseases. In these diseases, PKM2 can exert various biological functions, including regulation of glycolysis, inflammatory responses, apoptosis, proliferation of cells, oxidative stress, mitochondrial dysfunction, or pathological autoimmune responses. Moreover, the complexity of PKM2's biological characteristics determines the diversity of its biological functions. However, the role of PKM2 is not entirely the same in different diseases or cells, which is related to its oligomerization, subcellular localization, and post-translational modifications. This article will focus on the biological characteristics of PKM2, the regulation of PKM2 expression, and the biological role of PKM2 in neurological diseases. With this review, we hope to have a better understanding of the molecular mechanisms of PKM2, which may help researchers develop therapeutic strategies in clinic.

High-mobility group box 1 fragment ameliorates chronic pancreatitis induced by caerulein in mice

BACKGROUND

Chronic pancreatitis (CP) is a progressive disease characterized by pancreatic fibrosis for which effective treatment options are lacking. Mesenchymal stem cells (MSCs) have shown potential for fibrosis treatment but face limitations in clinical application. The high-mobility group box 1 (HMGB1) fragment mobilizes MSCs from bone marrow into the blood and has emerged as a promising therapeutic agent for tissue regeneration in various pathological conditions. The aim of this study was to investigate the potential therapeutic effects of systemic administration of the HMGB1 fragment in a mouse model of CP.

METHODS

A caerulein-induced CP mouse model was used, and the HMGB1 fragment was administered by tail vein injection. Parameters such as body weight, pancreatic tissue damage, fibrosis, inflammatory cytokine expression, and collagen-related gene expression were evaluated using various assays, including immunohistochemistry, real-time PCR, serum analysis, and single-cell transcriptome analysis. And the migration of MSCs to the pancreas was evaluated using the parabiosis model.

RESULTS

Administration of the HMGB1 fragment was associated with significant improvements in pancreatic tissue damage and fibrosis. It suppressed the expression of inflammatory cytokines and activated platelet-derived growth factor receptor-α+ MSCs, leading to their accumulation in the pancreas. The HMGB1 fragment also shifted gene expression patterns associated with pancreatic fibrosis toward those of the normal pancreas. Systemic administration of the HMGB1 fragment demonstrated therapeutic efficacy in attenuating pancreatic tissue damage and fibrosis in a CP mouse model.

CONCLUSION

These findings highlight the potential of the HMGB1 fragment as a therapeutic target for the treatment of CP.

Single-cell atlas of peripheral blood by CyTOF revealed peripheral blood immune cells metabolic alterations and neutrophil changes in intracranial aneurysm rupture

Previous studies have found that the peripheral immune environment is closely related to the occurrence and development of intracranial aneurysms. However, it remains unclear how the metabolism of peripheral blood mononuclear cells (PBMCs) and the composition of polymorphonuclear leukocytes (PMNs) changes in the process of intracranial aneurysm rupture. This study utilized cytometry by time of flight technology to conduct single-cell profiling analysis of PBMCs and PMNs from 72 patients with IAs. By comparing the expression differences of key metabolic enzymes in PBMCs between patients with ruptured intracranial aneurysms (RIAs) and unruptured intracranial aneurysms, we found that most PBMCs subsets from RIA group showed upregulation of rate-limiting enzymes related to the glycolytic pathway. By comparing the composition of PMNs, it was found that the proinflammatory CD101+HLA DR+ subsets were increased in the RIA group, accompanied by a decrease in the anti-inflammatory polymorphonuclear myeloid-derived suppressor cells. In conclusion, this study showed the changes in the peripheral immune profile of RIAs, which is helpful for our understanding of the mechanisms underlying peripheral changes and provides a direction for future related research.

Phosphorylation of PFKL regulates metabolic reprogramming in macrophages following pattern recognition receptor activation

Innate immune responses are linked to key metabolic pathways, yet the proximal signaling events that connect these systems remain poorly understood. Here we show that phosphofructokinase 1, liver type (PFKL), a rate-limiting enzyme of glycolysis, is phosphorylated at Ser775 in macrophages following several innate stimuli. This phosphorylation increases the catalytic activity of PFKL, as shown by biochemical assays and glycolysis monitoring in cells expressing phosphorylation-defective PFKL variants. Using a genetic mouse model in which PFKL Ser775 phosphorylation cannot take place, we observe that upon activation, glycolysis in macrophages is lower than in the same cell population of wild-type animals. Consistent with their higher glycolytic activity, wild-type cells have higher levels of HIF1α and IL-1β than PfklS775A/S775A after LPS treatment. In an in vivo inflammation model, PfklS775A/S775A mice show reduced levels of MCP-1 and IL-1β. Our study thus identifies a molecular link between innate immune activation and early induction of glycolysis.

Dysregulated cytokine and oxidative response in hyper-glycolytic monocytes in obesity

Introduction

Obesity is associated with a plethora of health complications, including increased susceptibility to infections or decreased vaccine efficacy, partly due to dysregulated immune responses. Monocytes play a crucial role in innate immunity, yet their functional alterations in obesity remain poorly understood.

Methods

Here, we employed proteomic and metabolomic analyses to investigate monocyte characteristics in individuals with overweight, obesity, impaired glucose tolerance (IGT), and type 2 diabetes (T2D), compared to lean donors.

Results and discussion

Our results revealed distinct molecular signatures in monocytes from individuals with obesity, with significant alterations in pathways related to metabolism, cellular migration, and phagocytosis. Moreover, LPS-induced activation of monocytes unveiled heightened metabolic reprogramming towards glycolysis in subjects with obesity accompanied by dysregulated cytokine responses and elevated oxidative stress. Additionally, monocytes from donors with obesity exhibited increased lipid droplet accumulation. These findings shed light on the immunometabolic dysregulation underlying obesity-associated immune dysfunction, highlighting potential targets for therapeutic intervention.

Lactate and Lactylation in Sepsis: A Comprehensive Review

Sepsis is a disorder of the immune response to infection or infectious factors with high morbidity and mortality in clinical settings. The lactylation of lysine residues, fueled by lactate, plays a pivotal role in its pathophysiology. In conducting a literature review on sepsis-related research, we employed a systematic approach to ensure comprehensiveness and accuracy. Initially, we conducted an extensive literature search through the PubMed database, utilizing a range of keywords including "sepsis", "lactate", "lactylation", and "epigenetic modification". The aim was to capture the most recent research related to the pathophysiological mechanisms of sepsis, metabolic disorders, and the role of lactylation. The results of the literature review revealed a close link between sepsis and metabolic dysfunction, particularly the pivotal role of lactylation in regulating immune responses and inflammatory processes. Lactate, not only an energy metabolic byproduct produced during glycolysis, affects the activity of various proteins, including those involved in immune regulation and cell signaling, through lactylation. In the context of sepsis, changes in the levels of lactylation may be closely associated with the severity and prognosis of the disease. In summary, lactylation, as an emerging type of epigenetic modification, provides a new perspective for the diagnosis and treatment of sepsis. Future research needs to further elucidate the exact mechanisms of lactylation in sepsis and explore its potential as a therapeutic target.