Hexokinase 1 cellular localization regulates the metabolic fate of glucose

FTO-associated osteoclastogenesis promotes alveolar bone resorption in apical periodontitis male rat via the HK1/USP14/RANK pathway

Alveolar bone resorption (ABR) is a key pathological manifestation in the development of apical periodontitis (AP) and contributes to the AP-associated tooth loss among AP patients in the clinic. However, the underlying mechanism of ABR development is largely unknown. Here we show, the total levels of N6-methyladenosine (m6A) were reduced in AP male rat alveolar bone tissues and BMDM-derived osteoclasts (OC), which was associated with the up-regulation of obesity-associated protein (FTO). Subsequently FTO-mediated hexokinase (HK1) demethylation modification enhancing glycolytic pathway that stabilizes receptor activator of NF-κB (RANK) protein via the deubiquitination activity of ubiquitin-specific protease 14 (USP14), which further promotes osteoclastogenesis to participate in the AP-related ABR development. Finally, Dac51 (an FTO inhibitor) and 2-DG (an HK1 inhibitor) both exhibit the inhibitory activity of osteoclastogenesis. Our current study reveals a molecular mechanism on osteoclastogenesis-related ABR and provides a therapeutic target of AP via modulating the FTO/HK1/USP14/RANK axis.

Hexokinase-I directly binds to a charged membrane-buried glutamate of mitochondrial VDAC1 and VDAC2

Binding of hexokinase HKI to mitochondrial voltage-dependent anion channels (VDACs) has far-reaching physiological implications. However, the structural basis of this interaction is unclear. Combining computer simulations with experiments in cells, we here show that complex assembly relies on intimate contacts between the N-terminal α-helix of HKI and a charged membrane-buried glutamate on the outer wall of VDAC1 and VDAC2. Protonation of this residue blocks complex formation in silico while acidification of the cytosol causes a reversable release of HKI from mitochondria. Membrane insertion of HKI occurs adjacent to the bilayer-facing glutamate where a pair of polar channel residues mediates a marked thinning of the cytosolic leaflet. Disrupting the membrane thinning capacity of VDAC1 dramatically impairs its ability to bind HKI in silico and in cells. Our data reveal key topological and mechanistic insights into HKI-VDAC complex assembly that may benefit the development of therapeutics to counter pathogenic imbalances in this process.

De-SUMO1ylated hexokinase 1 selectively degraded by ubiquitin-proteasome pathway promotes boar sperm capacitation in vitro

This study investigates the effect of de-SUMOylated hexokinase 1 (HK1) degradation on sperm capacitation in vitro. Sperm from adult Landrace pigs was divided into three groups: non-capacitated group, capacitated group, and 16 mM 2-deoxy-D-glucose (2-DG) group. Immunoprecipitation was performed to detect the binding levels of HK1 and small ubiquitin-like modifier 1 (SUMO1) before and after capacitation. Western blotting was used to assess the degradation pathways of HK1 and tyrosine phosphorylation levels after capacitation. Immunofluorescence was employed to localize HK1 and SUMO1 in sperm. A kit was used to measure pyruvate and adenosine triphosphate (ATP) content. Fluorescent staining was used to detect reactive oxygen species (ROS) levels, zinc (Zn²⁺) levels, calcium (Ca²⁺) levels, and mitochondrial membrane potential (MMP) in sperm. Hoechst 33342 staining was used to visualize sperm nuclei and assess sperm-oocyte adhesion rates. The results showed that inhibition of HK1 activity significantly reduced pyruvate and ATP content, sperm capacitation markers (tyrosine phosphorylation, Zn²⁺), MMP, and sperm adhesion rates (P < 0.05), while significantly increasing ROS levels in capacitated sperm (P < 0.01). Immunoprecipitation and Western blotting results indicated that HK1 undergoes de-SUMOylation during capacitation and is selectively degraded via the ubiquitin-proteasome pathway (P < 0.01). Our findings suggest that de-SUMOylated HK1 activates the glycolytic pathway through ubiquitin-proteasome pathway (UPP) degradation, thereby promoting sperm capacitation. These results provide new theoretical insights into the molecular mechanisms of sperm capacitation.

Hexokinase detachment from mitochondria drives the Warburg effect to support compartmentalized ATP production

Hexokinase (HK) catalyzes the synthesis of glucose-6-phosphate, marking the first committed step of glucose metabolism. Most cancer cells express two homologous isoforms (HK1 and HK2) that can each bind to the outer mitochondrial membrane (OMM). CRISPR screens across hundreds of cancer cell lines indicate that both are dispensable for cell growth in traditional culture media. By contrast, HK2 deletion impairs cell growth in Human Plasma-Like Medium (HPLM). Here, we find that HK2 is required to maintain sufficient cytosolic (OMM-detached) HK activity under conditions that enhance HK1 binding to the OMM. Notably, OMM-detached rather than OMM-docked HK promotes "aerobic glycolysis" (Warburg effect), an enigmatic phenotype displayed by most proliferating cells. We show that several proposed theories for this phenotype cannot explain the HK2 dependence and instead find that HK2 deletion severely impairs glycolytic ATP production with little impact on total ATP yield for cells in HPLM. Our results reveal a basis for conditional HK2 essentiality and suggest that demand for compartmentalized ATP synthesis underlies the Warburg effect.

Tumor-Intrinsic Kinome Landscape of Pancreatic Cancer Reveals New Therapeutic Approaches

SIGNIFICANCE

We provide a comprehensive tumor-intrinsic kinome landscape that provides a roadmap for the use of kinase inhibitors in PDAC treatment approaches.

Phenolic acids from Anisopus mannii modulates phosphofructokinase 1 to improve glycemic control in patients with type 2 diabetes: A double-blind, randomized, clinical trial

Phenolic acid-rich fraction from Anisopus mannii (PhAM) contains abundance of ferulic acid, gallic acid, protocatechuic acid, and syringic acid. Among other glycolytic enzymes, in vitro, PhAM counteracted the binding of sodium orthovanadate to phosphofructokinase 1 (PFK-1), improving its activities. In a rat model of diet-induced diabetes, PhAM monotherapy reduced HbA1c by an average of 0.63 % and fasting plasma glucose by 25 mg/dl. This herb rescued β-cells from streptozotocin-mediated destruction, thereby improving glycemic control. Supported by the preclinical trial, eighty-five patients with type 2 diabetes (T2D) receiving first-line medications were enrolled in a double-blind, randomized, placebo-controlled trial with a 90 % power level. Patients were randomized into a placebo group or either of the following two treatment groups: oral administration of 12 mg or 20 mg/kg body weight of PhAM once every 48 h for 6 months. Both treatments were well tolerated. At the endpoint, more than 70 % of patients achieved a 0.5 - 2.0 decrease in HbA1c levels and a > 20 mg/dl decrease in fasting blood glucose, meeting the pre-specified primary outcome. 66 % of patients treated with 20 mg PhAM achieved the < 7 % HbA1c and HOMA-IR of > 1.0 goal. respectively. Our study shows that PhAM can supplement first-line medications to achieve target glycemic control within 6 months.

The alterations of ocular surface metabolism and the related immunity inflammation in dry eye

Background

Dry eye disease (DED) stands as a prominent ocular condition of global prevalence, emerging as a growing concern within public health. However, the underlying mechanisms involved in its pathogenesis remain largely unknown. In recent years, with the development of metabolomics, numerous studies have reported alterations in ocular surface metabolism in DED and offered fresh perspectives on the development of DED.

Main text

The metabolic changes of the ocular surface of DED patients are closely intertwined with the cellular metabolism process and immune inflammation changes. This article expounds upon the correlation between ocular surface metabolism and immune inflammation alterations in DED in terms of glycolysis, lipid metabolism, amino acid metabolism, cellular signaling pathways, and immune inflammation regulation.

Conclusions

The alterations in ocular surface metabolism of patients with dry eye are closely associated with their inflammatory status. Our work contributes novel insights into the pathogenesis of dry eye diseases and offers innovative molecular targets for diagnosing, detecting, and managing DED patients.

Sinomenine modulates the metabolic reprogramming induced by sepsis via CHRNA7

BACKGROUND AND PURPOSE

Sepsis is a condition capable of causing systemic inflammation and metabolic reprogramming. Previous studies have shown that sinomenine (SIN) can mitigate sepsis by reducing inflammation, while the effect on metabolic reprogramming is unclear. The aim of this study is to investigate the function of SIN in metabolic reprogramming in sepsis.

EXPERIMENTAL APPROACH

Differential metabolites in lung tissue and serum were analyzed by 1H Nuclear Magnetic Resonance (1H NMR) and metabolomics were used to compare metabolic changes in septic mice. Nicotinic acetylcholine receptors alpha7 subunit (CHRNA7)-Knockdown (KD) mice and other techniques, were used to detect the expression of markers of several metabolic pathways.

KEY RESULTS

Metabolomics studies showed that SIN could affect energy metabolism, particularly glucose metabolism, and this effect may be related to the activation of CHRNA7. Further studies showed that SIN could inhibit aerobic glycolysis, promote glutamine anaplerosis, reduce pentose phosphate pathway flux and ultimately mediate metabolic reprogramming.

CONCLUSION AND IMPLICATIONS

SIN restores glycolysis and glutamine anaplerosis by interacting with CHRNA7, thereby mediating metabolic reprogramming and mitigating sepsis. These findings shed light on the mechanism of SIN in attenuating sepsis from a metabolic perspective.

Revisiting of Cancer Immunotherapy: Insight from the Dialogue between Glycolysis and PD-1/PD-L1 Axis in the Tumor Microenvironment

The interplay between metabolic pathways and immune escape has emerged as a captivating research area in oncobiology. Among these, the Warburg effect stands out as a hallmark metabolic reprogramming in cancer, characterized by elevated glucose utilization and excessive lactic acid production through anaerobic glycolysis. Key glycolytic enzymes not only fulfill the bioenergetic demands of cancer cells but also exhibit moonlighting roles, including regulation of epigenetic modifications, protein kinase activity, and immune escape mechanisms, thereby reshaping the tumor microenvironment. Tumor-specific vascular architecture facilitates lactate accumulation, which drives tumor progression by impairing immune cell function and acting as a signaling molecule to recruit immunosuppressive cells and modulate immune checkpoint pathways. The PD-1/PD-L1 co-stimulatory pathway plays a crucial role in negatively modulating the activation, proliferation, and cytokine secretion by T-lymphocytes. This review primarily focuses on elucidating the regulation and mechanisms underlying PD-1/PD-L1 signaling axis during glycolysis in tumor cells as well as surrounding cells. In the era of precision medicine, there is a particular interest in leveraging 18F-FDG PET/CT imaging as a valuable tool to assess PD-L1 expression status for more targeted therapeutic interventions. Additionally, the development of natural compounds capable of modulating metabolism opens new avenues for metabolism-based immunotherapy, though further studies are required to validate their in vivo efficacy.

ROCK Inhibitor Enhances Resilience Against Metabolic Stress Through Increasing Bioenergetic Capacity in Corneal Endothelial Cells

Purpose

To investigate the effect of Rho-associated protein kinase (ROCK) inhibitor Y27632 on bioenergetic capacity and resilience of corneal endothelial cells (CECs) under metabolic stress.

Methods

Bovine CECs (BCECs) were treated with Y27632 and subjected to bioenergetic profiling using the Seahorse XFp Analyzer. The effects on adenosine triphosphate (ATP) production through oxidative phosphorylation and glycolysis were measured. BCECs were also challenged with monensin to induce metabolic stress. Cell viability, apoptosis, intracellular sodium levels, and hexokinase localization were assessed using calcein AM assay, flow cytometry, fluorescence imaging, and immunostaining, respectively.

Results

Y27632 increased maximal ATP production rates via both oxidative phosphorylation and glycolysis, thereby expanding the overall bioenergetic capacity in BCECs. Under monensin-induced metabolic stress, ROCK inhibitor pretreatment significantly enhanced glycolytic ATP production and reduced apoptosis compared with untreated cells. Y27632 also facilitated sodium export by increasing Na/K-ATPase activity, as evidenced by lower intracellular sodium levels. Additionally, Y27632 promoted the translocation of hexokinase 2 to mitochondria under stress conditions, thereby enhancing glycolytic capacity. The effect of Y27632 on cell viability and sodium export was abrogated when cells were forced to rely on oxidative phosphorylation in galactose media, indicating that the protective effects of Y27632 are dependent on glycolytic ATP production under monensin stress.

Conclusions

ROCK inhibitor Y27632 enhances the bioenergetic capacity of BCECs, allowing the cells to better withstand metabolic stress by rapidly generating ATP to meet increased energy demands, maintaining ion homeostasis and reducing apoptosis.

The skeletal muscle proteomic determinants of neuromuscular function in young and older women following 8 weeks of resistance training

Resistance training (RT) is the gold standard intervention for ameliorating sarcopenia. Outstanding mechanistic questions remain regarding the malleability of the molecular determinants of skeletal muscle function in older age. Discovery of proteomics can expand such knowledge. We aimed to compare the effect of RT on the skeletal muscle proteome and neuromuscular function (NMF) in older and younger women. Seven young (22 ± 6 years) and eight older (63 ± 5 years) women completed 8 weeks' leg RT. Pre- and post-training, measures of leg and handgrip strength, NMF and vastus lateralis (VL) biopsies were obtained. Tandem-mass-tagged skeletal muscle proteomic analyses were performed. Data were analysed using differential expression and weighted gene co-expression network approaches. Proteins related to skeletal muscle contraction were lower in older skeletal muscle; this was not normalised by RT. Following RT, older women had higher expression of VL mitochondrial biogenesis proteins compared to the young, a reversal of pre-training observations. Seventy proteins were differentially expressed between age groups. VL expression of these proteins in older women was consistently and significantly associated with poorer leg strength/NMF. Conversely, VL expression of these proteins in older women was often associated with greater handgrip strength. This study has identified important differences in the molecular responses of young and old skeletal muscle to RT. We have demonstrated their close relationship with skeletal muscle function. Proteins that are refractory to RT may represent targets to ameliorate sarcopenia. We have described a 'proteomic-function' relationship that appears to be muscle-specific. Future research should further unpick these complex relationships.

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.

Inhibition of furin in CAR macrophages directs them toward a proinflammatory phenotype and enhances their antitumor activities

Chimeric antigen receptor (CAR)-T-cell therapy has revolutionized cellular immunotherapy, demonstrating remarkable efficacy in hematological cancers. However, its application in solid tumors faces significant challenges, including limited T-cell infiltration and tumor-induced immunosuppression. Given the prominent role of macrophages in the tumor microenvironment, their phenotypic plasticity and inherent antitumor properties, such as phagocytosis, offer a promising avenue for therapeutic intervention. This study focuses on the development of a second generation of CAR macrophages (CAR-Ms). We elucidated the role of the proprotein convertase furin in macrophages, demonstrating its overexpression in the presence of tumor cells. Importantly, furin inhibition maintains a proinflammatory macrophage phenotype, potentially redirecting them towards an antitumor state. Compared to furin-expressing counterparts, furin-inhibited CAR-Ms exhibited heightened antitumor phagocytic activity against breast cancer cells and ex vivo patient-derived tumoroids. Notably, they sustained a persistent proinflammatory profile, indicative of enhanced tumoricidal potential. Additionally, furin-inhibited CAR-Ms secreted factors that promote T-cell activation, offering a means to modulate the tumor microenvironment. In summary, our work highlights the translational potential of furin-inhibited CAR-Ms as a potent cellular therapy to mitigate macrophage exhaustion within the tumor environment. By capitalizing on macrophage-mediated antitumor responses, these findings pave the way for the development of second-generation CAR-M therapeutic strategies tailored for solid tumors.

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.

Ancient duplications, multidimensional specializations, and defense role of hexokinases in wheat

Hexokinases (HXKs), which sense and catalyze cellular sugar, play a critical role in the growth and development of various plants, including wheat, a primary source of human calories frequently attacked by fungal pathogens. However, the evolutionary dynamics and functional diversification of HXKs in wheat, particularly their roles in plant defense, remain unclear. Here, we discovered that the wheat hexokinase gene family originated through multiple ancient gene duplications across different plant lineages and has undergone comprehensive, multidimensional functional specialization in gene expression, subcellular localization, enzyme activity, and regulation of plant defense responses. Gene expression analysis suggests that two-thirds of the TaHXK genes are responsive to fungal infection. Subcellular analysis reveals that while six TaHXKs are localized in mitochondria, three TaHXKs from different phylogenetic branches are sorted into other cellular compartments. Notably, biochemical analysis shows that TaHXKs in mitochondria differ in their glucose-catalyzing activity, with TaHXK5 and TaHXK3 exhibiting the highest and lowest enzyme activity, respectively. Consistently, transient expression analysis suggests that TaHXK5 induces various plant defense responses, while TaHXK3 is defective in activating some plant defense responses. Furthermore, inactivation of the glucokinase activity of TaHXK5 compromised its function in defense activation, suggesting that mitochondrial TaHXKs display functional divergence in both enzyme activity and defense-inducing activity that are intrinsically connected. Overall, our findings reveal that the multidimensional specialization events following the ancient duplication events may have shaped the functional diversity of HXKs in wheat, shedding light on their evolutionary dynamics and potentially contributing to the improvement of wheat defense.

Clinical report and genetic analysis of a Chinese family with retinitis pigmentosa 79 caused by a novel loss-of-function HK1 variant

BACKGROUND

Retinitis pigmentosa (RP) is a genetically heterogeneous disease. RP 79 has been associated with heterozygous variants of hexokinase 1 (HK1). Only two missense HK1 variants have been reported in 11 families.

OBJECTIVE

To discover the molecular pathogenic mechanism of RP and validate the biological harm of HK1 through in vitro experiments.

METHODS

We conducted a genetic analysis of a 3-year-old female patient with RP and her family. We also evaluated the ocular phenotypes caused by HK1 (the identified variant). Peripheral blood samples were collected from the patient, her parents, and her brother, and trio whole-exome sequencing was performed. A protein structure analysis was performed to assess the functional impact of the variant, and a mutant plasmid was constructed for the quantitative polymerase chain reaction (qPCR) and western blot (WB) analysis of the effects of the variant on transcription and protein translation.

RESULTS

The patient harbored the NM_000188.3: c.613del (p.Ala205Leufs*3) variant, which is a heterozygous variant of HK1. Sanger sequencing confirmed the presence of this variant in the patient; however, the patient's parents and brother had the wild-type variant. The protein structure analysis indicated that the variant resulted in a truncated protein caused by premature termination of amino acid coding. The qPCR results indicated that the variant may not have affected the transcription process. However, the WB analysis demonstrated that the mutant HK-1 protein was not expressed and that the wild-type group exhibited normal expression.

CONCLUSIONS

Our patient had a loss-of-function (LoF) variant of HK1, which may be the genetic cause of typical features of RP that are observed at an early age. These findings expand the spectrum of HK1 variants and phenotypes and suggest that LoF variants of HK1 may represent a specific pathogenic mechanism of RP.

Exploring Smad5: a review to pave the way for a deeper understanding of the pathobiology of common respiratory diseases

Smad5 (small mothers against decapentaplegic 5) protein is a receptor-regulated member of the Smad family proteins, mainly participating in the bone morphogenetic protein (BMP) signaling pathway in its phosphorylated form. This article will provide a detailed review of Smad5, focusing on its gene characteristics, protein structure, and subcellular localization properties. We will also explore the related signaling pathways and the mechanisms of Smad5 in respiratory diseases, including chronic obstructive pulmonary disease (COPD), bronchial asthma, pulmonary arterial hypertension(PAH), lung cancer, and idiopathic pulmonary fibrosis (IPF). Additionally, the review will cover aspects such as proliferation, differentiation, apoptosis, anti-fibrosis, and mitochondrial function metabolism. In addition, the review will cover aspects of proliferation, differentiation, apoptosis, anti-fibrosis and functional mitochondrial metabolism related to the above topics. Numerous studies suggest that Smad5 may play a unique and important role in the pathogenesis of respiratory system diseases. However, in previous research, Smad5 was mainly used to broadly determine the activation of the BMP signaling pathway, and its own function has not been given much attention. It is worth noting that Smad5 has distinct nuclear-cytoplasmic distribution characteristics different from Smad1 and Smad8. It can undergo significant nuclear-cytoplasmic shuttling when intracellular pH (pHi) changes, playing important roles in both the classical BMP signaling pathway and non-BMP signaling pathways. Given that Smad5 can move intracellularly in response to changes in physicochemical properties, its cellular localization may play a crucial role in the development of respiratory diseases. This article will explore the possibility that its distribution characteristics may be an important factor that is easily overlooked and not adequately considered in disease research.

Elucidating the spatiotemporal dynamics of glucose metabolism with genetically encoded fluorescent biosensors

Glucose metabolism has been well understood for many years, but some intriguing questions remain regarding the subcellular distribution, transport, and functions of glycolytic metabolites. To address these issues, a living cell metabolic monitoring technology with high spatiotemporal resolution is needed. Genetically encoded fluorescent sensors can achieve specific, sensitive, and spatiotemporally resolved metabolic monitoring in living cells and in vivo, and dozens of glucose metabolite sensors have been developed recently. Here, we highlight the importance of tracking specific intermediate metabolites of glycolysis and glycolytic flux measurements, monitoring the spatiotemporal dynamics, and quantifying metabolite abundance. We then describe the working principles of fluorescent protein sensors and summarize the existing biosensors and their application in understanding glucose metabolism. Finally, we analyze the remaining challenges in developing high-quality biosensors and the huge potential of biosensor-based metabolic monitoring at multiple spatiotemporal scales.

PI3K-dependent reprogramming of hexokinase isoforms controls glucose metabolism and functional responses of B lymphocytes

B lymphocyte activation triggers metabolic reprogramming essential for B cell differentiation and mounting a healthy immune response. Here, we investigate the regulation and function of glucose-phosphorylating enzyme hexokinase 2 (HK2) in B cells. We report that both activation-dependent expression and mitochondrial localization of HK2 are regulated by the phosphatidylinositol 3-kinase (PI3K) signaling pathway. B cell-specific deletion of HK2 in mice caused mild perturbations in B cell development. HK2-deficient B cells show impaired functional responses in vitro and adapt to become less dependent on glucose and more dependent on glutamine. HK2 deficiency impairs glycolysis, alters metabolite profiles, and alters flux of labeled glucose carbons into downstream pathways. Upon immunization, HK2-deficient mice exhibit impaired germinal center, plasmablast, and antibody responses. HK2 expression in primary human chronic lymphocytic leukemia (CLL) cells was associated with recent proliferation and could be reduced by PI3K inhibition. Our study implicates PI3K-dependent modulation of HK2 in B cell metabolic reprogramming.

Pathophysiological role and potential drug target of NLRP3 inflammasome in the metabolic disorders

NLRP3 plays a role in the development of autoinflammatory diseases. NLRP3, ASC, and Caspases 1 or 8 make up the NLRP3 inflammasome, which is an important part of innate immune system. The NLRP3 inflammasome-mediated inflammatory cytokines may also participate in metabolic disorders, such as diabetes, hyperlipidemia, atherosclerosis, non-alcoholic fatty liver disease, and gout. Hence, an overview of the NLRP3 regulation in these metabolic diseases and the potential drugs targeting NLRP3 is the focus of this review.

Parthanatos: Mechanisms, modulation, and therapeutic prospects in neurodegenerative disease and stroke

Parthanatos is a cell death signaling pathway that has emerged as a compelling target for pharmaceutical intervention. It plays a pivotal role in the neuron loss and neuroinflammation that occurs in Parkinson's Disease (PD), Alzheimer's Disease (AD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS), and stroke. There are currently no treatments available to humans to prevent cell death in any of these diseases. This review provides an in-depth examination of the current understanding of the Parthanatos mechanism, with a particular focus on its implications in neuroinflammation and various diseases discussed herein. Furthermore, we thoroughly review potential intervention targets within the Parthanatos pathway. We dissect recent progress in inhibitory strategies, complimented by a detailed structural analysis of key Parthanatos executioners, PARP-1, AIF, and MIF, along with an assessment of their established inhibitors. We hope to introduce a new perspective on the feasibility of targeting components within the Parthanatos pathway, emphasizing its potential to bring about transformative outcomes in therapeutic interventions. By delineating therapeutic opportunities and known targets, we seek to emphasize the imperative of blocking Parthanatos as a precursor to developing disease-modifying treatments. This comprehensive exploration aims to catalyze a paradigm shift in our understanding of potential neurodegenerative disease therapeutics, advocating for the pursuit of effective interventions centered around Parthanatos inhibition.

Metabolic reprogramming of macrophages in cancer therapy

Cancer presents a significant global public health challenge. Within the tumor microenvironment (TME), macrophages are the most abundant immune cell population. Tumor-associated macrophages (TAMs) undergo metabolic reprogramming through influence of the TME; thus, by manipulating key metabolic pathways such as glucose, lipid, or amino acid metabolism, it may be possible to shift TAMs towards an antitumor state, enhancing the immune response against tumors. Here, we highlight the metabolic reprogramming of macrophages as a potential approach for cancer immunotherapy. We explore the major pathways involved in the metabolic reprogramming of TAMs and offer new and valuable insights on the current technologies utilized for TAM reprogramming, including genome editing, antibodies, small molecules, nanoparticles and other in situ editing strategies.

Organization of a functional glycolytic metabolon on mitochondria for metabolic efficiency

Glucose, the primary cellular energy source, is metabolized through glycolysis initiated by the rate-limiting enzyme hexokinase (HK). In energy-demanding tissues like the brain, HK1 is the dominant isoform, primarily localized on mitochondria, and is crucial for efficient glycolysis-oxidative phosphorylation coupling and optimal energy generation. This study unveils a unique mechanism regulating HK1 activity, glycolysis and the dynamics of mitochondrial coupling, mediated by the metabolic sensor enzyme O-GlcNAc transferase (OGT). OGT catalyses reversible O-GlcNAcylation, a post-translational modification influenced by glucose flux. Elevated OGT activity induces dynamic O-GlcNAcylation of the regulatory domain of HK1, subsequently promoting the assembly of the glycolytic metabolon on the outer mitochondrial membrane. This modification enhances the mitochondrial association with HK1, orchestrating glycolytic and mitochondrial ATP production. Mutation in HK1's O-GlcNAcylation site reduces ATP generation in multiple cell types, specifically affecting metabolic efficiency in neurons. This study reveals a previously unappreciated pathway that links neuronal metabolism and mitochondrial function through OGT and the formation of the glycolytic metabolon, providing potential strategies for tackling metabolic and neurological disorders.

Host cell manipulation by microsporidia secreted effectors: Insights into intracellular pathogenesis

Microsporidia are prolific producers of effector molecules, encompassing both proteins and nonproteinaceous effectors, such as toxins, small RNAs, and small peptides. These secreted effectors play a pivotal role in the pathogenicity of microsporidia, enabling them to subvert the host's innate immunity and co-opt metabolic pathways to fuel their own growth and proliferation. However, the genomes of microsporidia, despite falling within the size range of bacteria, exhibit significant reductions in both structural and physiological features, thereby affecting the repertoire of secretory effectors to varying extents. This review focuses on recent advances in understanding how microsporidia modulate host cells through the secretion of effectors, highlighting current challenges and proposed solutions in deciphering the complexities of microsporidial secretory effectors.

Hesperetin-loaded chitosan nanoparticles ameliorate hyperglycemia by regulating key enzymes of carbohydrate metabolism in a diabetic rat model

The study aimed to investigate the potential of hesperetin-loaded chitosan nanoparticles (HSPCNPs) in alleviating hyperglycemia by modulating key enzymes in diabetic rats. Chitosan nanoparticles loaded with hesperetin were prepared using the ionic gelation method and characterized with Electron microscope (SEM), zeta potential, particle size analysis, Fourier-transform infrared (FT-IR), Energy dispersive spectroscopy (EDS) and Encapsulation efficiency and Loading efficiency. To induce diabetes, rats were fed a high-fat beef tallow diet for 28 days, then given a single dose of streptozotocin (STZ) at 35 mg/kg b.w in 0.1 M citrate buffer (pH 4.0). Rats were treated with HSPCNPs at doses of 10, 20, and 40 mg/kg b.w. The analyzed parameters included body weight, food and water intake, plasma glucose and insulin, liver and skeletal muscle glycogen levels, and carbohydrate metabolism. SEM imaging revealed dimensions between 124.2 and 251.6 nm and a mean particle size of 145.0 nm. FT-IR analysis confirmed the presence of functional groups in the chitosan nanoparticles, and the zeta potential was 35.5 mV. HSPCNP 40 mg/kg b.w significantly (p < 0.05) reduced blood glucose levels and glycosylated hemoglobin, improving body weight, food intake, and reducing water intake. In diabetic rats, enzymes for carbohydrate metabolism like fructose 1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and glucose 6-phosphatase are evaluated in the liver, while glucose 6 phosphate dehydrogenase and hexokinase activity were significantly lower. Additionally, plasma insulin levels increased, indicating enhanced insulin sensitivity. The results show that HSPCNPs at 40 mg/kg b.w. ameliorate hyperglycemia to provide robust protection against diabetic complications and significantly improve metabolic health.

MiR-34a-HK1 signal axis retards bone marrow mesenchymal stem cell senescence via ameliorating glycolytic metabolism

BACKGROUND

Mesenchymal stem cells (MSCs) are one of the most widely studied adult stem cells, while MSC replicative senescence occurs with serial expansion in vitro. We determined whether miR-34a can regulate MSC senescence by directly targeting glycolytic key enzymes to influence glycolysis.

METHODS

Detected the effects of miR-34a on MSC senescence and glycolytic metabolism through gene manipulation. Bioinformatics prediction and luciferase reporter assay were applied to confirm that HK1 is a direct target of miR-34a. The underlying regulatory mechanism of miR-34a targeting HK1 in MSC senescence was further explored by a cellular function recovery experiment.

RESULTS

In the current study, we revealed that miR-34a over-expression exacerbated senescence-associated characteristics and impaired glycolytic metabolism. Then we identified hexokinase1 (HK1) as a direct target gene of miR-34a. And HK1 replenishment reversed MSC senescence and reinforced glycolysis. In addition, miR-34a-mediated MSC senescence and lower glycolytic levels were evidently rescued following the co-treatment with HK1 over-expression.

CONCLUSION

The miR-34a-HK1 signal axis can alleviate MSC senescence via enhancing glycolytic metabolism, which possibly provides a novel mechanism for MSC senescence and opens up new possibilities for delaying and suppressing the occurrence and development of aging and age-related diseases.

HMGA1 promotes the progression of esophageal squamous cell carcinoma by elevating TKT-mediated upregulation of pentose phosphate pathway

Esophageal squamous cell carcinoma (ESCC) possesses a poor prognosis and treatment outcome. Dysregulated metabolism contributes to unrestricted growth of multiple cancers. However, abnormal metabolism, such as highly activated pentose phosphate pathway (PPP) in the progression of ESCC remains largely unknown. Herein, we report that high-mobility group AT-hook 1 (HMGA1), a structural transcriptional factor involved in chromatin remodeling, promoted the development of ESCC by upregulating the PPP. We found that HMGA1 was highly expressed in ESCC. Elevated HMGA1 promoted the malignant phenotype of ESCC cells. Conditional knockout of HMGA1 markedly reduced 4-nitroquinoline-1-oxide (4NQO)-induced esophageal tumorigenesis in mice. Through the metabolomic analysis and the validation assay, we found that HMGA1 upregulated the non-oxidative PPP. With the transcriptome sequencing, we identified that HMGA1 upregulated the expression of transketolase (TKT), which catalyzes the reversible reaction in non-oxidative PPP to exchange metabolites with glycolytic pathway. HMGA1 knockdown suppressed the PPP by downregulating TKT, resulting in the reduction of nucleotides in ESCC cells. Overexpression of HMGA1 upregulated PPP and promoted the survival of ESCC cells by activating TKT. We further characterized that HMGA1 promoted the transcription of TKT by interacting with and enhancing the binding of transcription factor SP1 to the promoter of TKT. Therapeutics targeting TKT with an inhibitor, oxythiamine, reduced HMGA1-induced ESCC cell proliferation and tumor growth. Together, in this study, we identified a new role of HMGA1 in ESCCs by upregulating TKT-mediated activation of PPP. Our results provided a new insight into the role of HMGA1/TKT/PPP in ESCC tumorigenesis and targeted therapy.

Hexokinase 1 forms rings that regulate mitochondrial fission during energy stress

Metabolic enzymes can adapt during energy stress, but the consequences of these adaptations remain understudied. Here, we discovered that hexokinase 1 (HK1), a key glycolytic enzyme, forms rings around mitochondria during energy stress. These HK1-rings constrict mitochondria at contact sites with the endoplasmic reticulum (ER) and mitochondrial dynamics protein (MiD51). HK1-rings prevent mitochondrial fission by displacing the dynamin-related protein 1 (Drp1) from mitochondrial fission factor (Mff) and mitochondrial fission 1 protein (Fis1). The disassembly of HK1-rings during energy restoration correlated with mitochondrial fission. Mechanistically, we identified that the lack of ATP and glucose-6-phosphate (G6P) promotes the formation of HK1-rings. Mutations that affect the formation of HK1-rings showed that HK1-rings rewire cellular metabolism toward increased TCA cycle activity. Our findings highlight that HK1 is an energy stress sensor that regulates the shape, connectivity, and metabolic activity of mitochondria. Thus, the formation of HK1-rings may affect mitochondrial function in energy-stress-related pathologies.

Therapeutic targeting of immunometabolism reveals a critical reliance on hexokinase 2 dosage for microglial activation and Alzheimer's progression

Neuroinflammation is a prominent feature of Alzheimer's disease (AD). Activated microglia undergo a reprogramming of cellular metabolism necessary to power their cellular activities during disease. Thus, selective targeting of microglial immunometabolism might be of therapeutic benefit for treating AD. In the AD brain, the levels of microglial hexokinase 2 (HK2), an enzyme that supports inflammatory responses by promoting glycolysis, are significantly increased. In addition, HK2 displays non-metabolic activities that extend its inflammatory role beyond glycolysis. The antagonism of HK2 affects microglial phenotypes and disease progression in a gene-dose-dependent manner. HK2 complete loss fails to improve pathology by exacerbating inflammation, while its haploinsufficiency reduces pathology in 5xFAD mice. We propose that the partial antagonism of HK2 is effective in slowing disease progression by modulating NF-κB signaling through its cytosolic target, IKBα. The complete loss of HK2 affects additional inflammatory mechanisms related to mitochondrial dysfunction.

Adipose-derived stem cell exosomes loaded with icariin alleviates rheumatoid arthritis by modulating macrophage polarization in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease marked by synovitis and cartilage destruction. The active compound, icariin (ICA), derived from the herb Epimedium, exhibits potent anti-inflammatory properties. However, its clinical utility is limited by its water insolubility, poor permeability, and low bioavailability. To address these challenges, we developed a multifunctional drug delivery system-adipose-derived stem cells-exosomes (ADSCs-EXO)-ICA to target active macrophages in synovial tissue and modulate macrophage polarization from M1 to M2. High-performance liquid chromatography analysis confirmed a 92.4 ± 0.008% loading efficiency for ADSCs-EXO-ICA. In vitro studies utilizing cellular immunofluorescence (IF) and flow cytometry demonstrated significant inhibition of M1 macrophage proliferation by ADSCs-EXO-ICA. Enzyme-linked immunosorbent assay, cellular transcriptomics, and real-time quantitative PCR indicated that ADSCs-EXO-ICA promotes an M1-to-M2 phenotypic transition by reducing glycolysis through the inhibition of the ERK/HIF-1α/GLUT1 pathway. In vivo, ADSCs-EXO-ICA effectively accumulated in the joints. Pharmacodynamic assessments revealed that ADSCs-EXO-ICA decreased cytokine levels and mitigated arthritis symptoms in collagen-induced arthritis (CIA) rats. Histological analysis and micro computed tomography confirmed that ADSCs-EXO-ICA markedly ameliorated synovitis and preserved cartilage. Further in vivo studies indicated that ADSCs-EXO-ICA suppresses arthritis by promoting an M1-to-M2 switch and suppressing glycolysis. Western blotting supported the therapeutic efficacy of ADSCs-EXO-ICA in RA, confirming its role in modulating macrophage function through energy metabolism regulation. Thus, this study not only introduces a drug delivery system that significantly enhances the anti-RA efficacy of ADSCs-EXO-ICA but also elucidates its mechanism of action in macrophage function inhibition.

Spermatogenic cell-specific type 1 hexokinase (HK1S) is essential for capacitation-associated increase in tyrosine phosphorylation and male fertility in mice

Hexokinase (HK) catalyzes the first irreversible rate-limiting step in glycolysis that converts glucose to glucose-6-phosphate. HK1 is ubiquitously expressed in the brain, erythrocytes, and other tissues where glycolysis serves as the major source of ATP production. Spermatogenic cell-specific type 1 hexokinase (HK1S) is expressed in sperm but its physiological role in male mice is still unknown. In this study, we generate Hk1s knockout mice using the CRISPR/Cas9 system to study the gene function in vivo. Hk1s mRNA is exclusively expressed in testes starting from postnatal day 18 and continuing to adulthood. HK1S protein is specifically localized in the outer surface of the sperm fibrous sheath (FS). Depletion of Hk1s leads to infertility in male mice and reduces sperm glycolytic pathway activity, yet they have normal motile parameters and ATP levels. In addition, by using in vitro fertilization (IVF), Hk1s deficient sperms are unable to fertilize cumulus-intact or cumulus-free oocytes, but can normally fertilize zona pellucida-free oocytes. Moreover, Hk1s deficiency impairs sperm migration into the oviduct, reduces acrosome reaction, and prevents capacitation-associated increases in tyrosine phosphorylation, which are probable causes of infertility. Taken together, our results reveal that HK1S plays a critical role in sperm function and male fertility in mice.

Gambogic acid exhibits promising anticancer activity by inhibiting the pentose phosphate pathway in lung cancer mouse model

BACKGROUND

The pentose phosphate pathway (PPP) plays a crucial role in the material and energy metabolism in cancer cells. Targeting 6-phosphogluconate dehydrogenase (6PGD), the rate-limiting enzyme in the PPP metabolic process, to inhibit cellular metabolism is an effective anticancer strategy. In our previous study, we have preliminarily demonstrated that gambogic acid (GA) induced cancer cell death by inhibiting 6PGD and suppressing PPP at the cellular level. However, it is unclear whether GA could suppress cancer cell growth by inhibiting PPP pathway in mouse model.

PURPOSE

This study aimed to confirm that GA as a covalent inhibitor of 6PGD protein and to validate that GA suppresses cancer cell growth by inhibiting the PPP pathway in a mouse model.

METHODS

Cell viability was detected by CCK-8 assays as well as flow cytometry. The protein targets of GA were identified using a chemical probe and activity-based protein profiling (ABPP) technology. The target validation was performed by in-gel fluorescence assay, the Cellular Thermal Shift Assay (CETSA). A lung cancer mouse model was constructed to test the anticancer activity of GA. RNA sequencing was performed to analyze the global effect of GA on gene expression.

RESULTS

The chemical probe of GA exhibited high biological activity in vitro. 6PGD was identified as one of the binding proteins of GA by ABPP. Our findings revealed a direct interaction between GA and 6PGD. We also found that the anti-cancer activity of GA depended on reactive oxygen species (ROS), as evidenced by experiments on cells with 6PGD knocked down. More importantly, GA could effectively reduce the production of the two major metabolites of the PPP in lung tissue and inhibit cancer cell growth in the mouse model. Finally, RNA sequencing data suggested that GA treatment significantly regulated apoptosis and hypoxia-related physiological processes.

CONCLUSION

These results demonstrated that GA was a covalent inhibitor of 6PGD protein. GA effectively suppressed cancer cell growth by inhibiting the PPP pathway without causing significant side effects in the mouse model. Our study provides in vivo evidence that elucidates the anticancer mechanism of GA, which involves the inhibition of 6PGD and modulation of cellular metabolic processes.

MiR-106a-5p targets PFKFB3 and improves sepsis through regulating macrophage pyroptosis and inflammatory response

The enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3) is a critical regulator of glycolysis and plays a key role in modulating the inflammatory response, thereby contributing to the development of inflammatory diseases such as sepsis. Despite its importance, the development of strategies to target PFKFB3 in the context of sepsis remains challenging. In this study, we employed a miRNA-based approach to decrease PFKFB3 expression. Through multiple meta-analyses, we observed a downregulation of miR-106a-5p expression and an upregulation of PFKFB3 expression in clinical sepsis samples. These changes were also confirmed in blood monocytes from patients with early sepsis and from a mouse model of lipopolysaccharide (LPS)-induced sepsis. Overexpression of miR-106a-5p significantly decreased the LPS-induced increase in glycolytic capacity, inflammatory response, and pyroptosis in macrophages. Mechanistically, we identified PFKFB3 as a direct target protein of miR-106a-5p and demonstrated its essential role in LPS-induced pyroptosis and inflammatory response in macrophages. Furthermore, treatment with agomir-miR-106a-5p conferred a protective effect in an LPS mouse model of sepsis, but this effect was attenuated in myeloid-specific Pfkfb3 KO mice. These findings indicate that miR-106a-5p inhibits macrophage pyroptosis and inflammatory response in sepsis by regulating PFKFB3-mediated glucose metabolism, representing a potential therapeutic option for the treatment of sepsis.

Network analysis of S-nitrosylated synaptic proteins demonstrates unique roles in health and disease

Nitric oxide can covalently modify cysteine thiols on target proteins to alter that protein's function in a process called S-nitrosylation (SNO). S-nitrosylation of synaptic proteins plays an integral part in neurotransmission. Here we review the function of the SNO-proteome at the synapse and whether clusters of SNO-modification may predict synaptic dysfunction associated with disease. We used a systematic search strategy to concatenate SNO-proteomic datasets from normal human or murine brain samples. Identified SNO-modified proteins were then filtered against proteins reported in the Synaptome Database, which provides a detailed and experimentally verified annotation of all known synaptic proteins. Subsequently, we performed an unbiased network analysis of all known SNO-synaptic proteins to identify clusters of SNO proteins commonly involved in biological processes or with known disease associations. The resulting SNO networks were significantly enriched in biological processes related to metabolism, whereas significant gene-disease associations were related to Schizophrenia, Alzheimer's, Parkinson's and Huntington's disease. Guided by an unbiased network analysis, the current review presents a thorough discussion of how clustered changes to the SNO-proteome influence health and disease.

NIR-II imaging-guided precise photodynamic therapy for augmenting tumor-starvation therapy by glucose metabolism reprogramming interference

Metabolic reprogramming is a mechanism by which cancer cells alter their metabolic patterns to promote cell proliferation and growth, thereby enabling their resistance to external stress. 2-Deoxy-D-glucose (2DG) can eliminate their energy source by inhibiting glucose glycolysis, leading to cancer cell death through starvation. However, a compensatory increase in mitochondrial metabolism inhibits its efficacy. Herein, we propose a synergistic approach that combines photodynamic therapy (PDT) with starvation therapy to address this challenge. To monitor the nanodrugs and determine the optimal triggering time for precise tumor therapy, a multifunctional nano-platform comprising lanthanide-doped nanoparticle (LnNP) cores was constructed and combined with mesoporous silicon shells loaded with 2DG and photosensitizer chlorin e6 (Ce6) in the mesopore channels. Under 980 nm near-infrared light excitation, the downshifted 1550 nm fluorescence signal in the second near-infrared (NIR-II, 1000-1700 nm) window from the LnNPs was used to monitor the accumulation of nanomaterials in tumors. Furthermore, upconverted 650 nm light excited the Ce6 to generate singlet oxygen for PDT, which damaged mitochondrial function and enhanced the efficacy of 2DG by inhibiting hexokinase 2 and lactate dehydrogenase A expressions. As a result, glucose metabolism reprogramming was inhibited and the efficiency of starvation therapy was significantly enhanced. Overall, the proposed NIR-II bioimaging-guided PDT-augmented starvation therapy, which simultaneously inhibited glycolysis and mitochondria, facilitated the effects of a cancer theranostic system.

S100A8/9 modulates perturbation and glycolysis of macrophages in allergic asthma mice

Background

Allergic asthma is the most prevalent asthma phenotype and is associated with the disorders of immune cells and glycolysis. Macrophages are the most common type of immune cells in the lungs. Calprotectin (S100A8 and S100A9) are two pro-inflammatory molecules that target the Toll-like receptor 4 (TLR4) and are substantially increased in the serum of patients with severe asthma. This study aimed to determine the effects of S100A8/A9 on macrophage polarization and glycolysis associated with allergic asthma.

Methods

To better understand the roles of S100A8 and S100A9 in the pathogenesis of allergic asthma, we used ovalbumin (OVA)-induced MH-S cells, and OVA-sensitized and challenged mouse models (wild-type male BALB/c mice). Enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, flow cytometry, hematoxylin-eosin staining, and western blotting were performed. The glycolysis inhibitor 3-bromopyruvate (3-BP) was used to observe changes in glycolysis in mice.

Results

We found knockdown of S100A8 or S100A9 in OVA-induced MH-S cells inhibited inflammatory cytokines, macrophage polarization biomarker expression, and pyroptosis cell proportion, but increased anti-inflammatory cytokine interleukin (IL)-10 mRNA; also, glycolysis was inhibited, as evidenced by decreased lactate and key enzyme expression; especially, knockdown of S100A8 or S100A9 inhibited the activity of TLR4/myeloid differentiation primary response gene 88 (MyD88)/Nuclear factor kappa-B (NF-κB) signaling pathway. Intervention with lipopolysaccharides (LPS) abolished the beneficial effects of S100A8 and S100A9 knockdown. The observation of OVA-sensitized and challenged mice showed that S100A8 or S100A9 knockdown promoted respiratory function, improved lung injury, and inhibited inflammation; knockdown of S100A8 or S100A9 also suppressed macrophage polarization, glycolysis levels, and activation of the TLR4/MyD88/NF-κB signaling pathway in the lung. Conversely, S100A9 overexpression exacerbated lung injury and inflammation, promoting macrophage polarization and glycolysis, which were antagonized by the glycolysis inhibitor 3-BP.

Conclusion

S100A8 and S100A9 play critical roles in allergic asthma pathogenesis by promoting macrophage perturbation and glycolysis through the TLR4/MyD88/NF-κB signaling pathway. Inhibition of S100A8 and S100A9 may be a potential therapeutic strategy for allergic asthma.

Poly(ADP-ribose) mediates bioenergetic defects and redox imbalance in neurons following oxygen and glucose deprivation

PARP-1 over-activation results in cell death via excessive PAR generation in different cell types, including neurons following brain ischemia. Glycolysis, mitochondrial function, and redox balance are key cellular processes altered in brain ischemia. Studies show that PAR generated after PARP-1 over-activation can bind hexokinase-1 (HK-1) and result in glycolytic defects and subsequent mitochondrial dysfunction. HK-1 is the neuronal hexokinase and catalyzes the first reaction of glycolysis, converting glucose to glucose-6-phosphate (G6P), a common substrate for glycolysis, and the pentose phosphate pathway (PPP). PPP is critical in maintaining NADPH and GSH levels via G6P dehydrogenase activity. Therefore, defects in HK-1 will not only decrease cellular bioenergetics but will also cause redox imbalance due to the depletion of GSH. In brain ischemia, whether PAR-mediated inhibition of HK-1 results in bioenergetics defects and redox imbalance is not known. We used oxygen-glucose deprivation (OGD) in mouse cortical neurons to mimic brain ischemia in neuronal cultures and observed that PARP-1 activation via PAR formation alters glycolysis, mitochondrial function, and redox homeostasis in neurons. We used pharmacological inhibition of PARP-1 and adenoviral-mediated overexpression of wild-type HK-1 (wtHK-1) and PAR-binding mutant HK-1 (pbmHK-1). Our data show that PAR inhibition or overexpression of HK-1 significantly improves glycolysis, mitochondrial function, redox homeostasis, and cell survival in mouse cortical neurons exposed to OGD. These results suggest that PAR binding and inhibition of HK-1 during OGD drive bioenergetic defects in neurons due to inhibition of glycolysis and impairment of mitochondrial function.

Bis(2-ethylhexyl)-tetrabromophthalate Poses a Higher Exposure Risk and Induces Gender-Specific Metabolic Disruptions in Zebrafish Liver

Bis(2-ethylhexyl)-tetrabromophthalate (TBPH), a typical novel brominated flame retardant, has been ubiquitously identified in various environmental and biotic media. Consequently, there is an urgent need for precise risk assessment based on a comprehensive understanding of internal exposure and the corresponding toxic effects on specific tissues. In this study, we first investigated the toxicokinetic characteristics of TBPH in different tissues using the classical pseudo-first-order toxicokinetic model. We found that TBPH was prone to accumulate in the liver rather than in the gonad, brain, and muscle of both female and male zebrafish, highlighting a higher internal exposure risk for the liver. Furthermore, long-term exposure to TBPH at environmentally relevant concentrations led to increased visceral fat accumulation, signaling potential abnormal liver function. Hepatic transcriptome analysis predominantly implicated glycolipid metabolism pathways. However, alterations in the profile of associated genes and biochemical indicators revealed gender-specific responses following TBPH exposure. Besides, histopathological observations as well as the inflammatory response in the liver confirmed the development of nonalcoholic fatty liver disease, particularly in male zebrafish. Altogether, our findings highlight a higher internal exposure risk for the liver, enhancing our understanding of the gender-specific metabolic-disrupting potential associated with TBPH exposure.

Nanozyme-Based Regulation of Cellular Metabolism and Their Applications

Metabolism is the sum of the enzyme-dependent chemical reactions, which produces energy in catabolic process and synthesizes biomass in anabolic process, exhibiting high similarity in mammalian cell, microbial cell, and plant cell. Consequently, the loss or gain of metabolic enzyme activity greatly affects cellular metabolism. Nanozymes, as emerging enzyme mimics with diverse functions and adjustable catalytic activities, have shown attractive potential for metabolic regulation. Although the basic metabolic tasks are highly similar for the cells from different species, the concrete metabolic pathway varies with the intracellular structure of different species. Here, the basic metabolism in living organisms is described and the similarities and differences in the metabolic pathways among mammalian, microbial, and plant cells and the regulation mechanism are discussed. The recent progress on regulation of cellular metabolism mainly including nutrient uptake and utilization, energy production, and the accompanied redox reactions by different kinds of oxidoreductases and their applications in the field of disease therapy, antimicrobial therapy, and sustainable agriculture is systematically reviewed. Furthermore, the prospects and challenges of nanozymes in regulating cell metabolism are also discussed, which broaden their application scenarios.

Multi-omics analysis reveals GAPDH posttranscriptional regulation of IFN-γ and PHGDH as a metabolic checkpoint of microglia polarization

A "switch" in the metabolic pattern of microglia is considered to be required to meet the metabolic demands of cell survival and functions. However, how metabolic switches regulate microglial function remains controversial. We found here that exposure to amyloid-β triggers microglial inflammation accompanied by increasing GAPDH levels. The increase of GAPDH, a glycolysis enzyme, leads to the reduced release of interferon-γ (IFN-γ) from inflammatory microglia. Such alternation is translational and is regulated by the binding of glycolysis enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to IFN-γ mRNA. GAPDH, by engaging/disengaging glycolysis and through influencing IFN-γ expression, regulates microglia functions, including phagocytosis and cytokine production. Phosphoglycerate dehydrogenase (PHGDH), screened from different state microglia by metabolomics combined with METARECON analysis, is a metabolic enzyme adjacent downstream of GAPDH and synthesizes serine on the collateral pathway derived from glycolysis. Polarization of microglial with PHGDH as a metabolic checkpoint can be bidirectionally regulated by adding IL-4 or giving PHGDH inhibitors. Therefore, regulation of metabolic enzymes not only reprograms metabolic patterns, but also manipulates microglia functions. Further study should be performed to explore the mechanism of metabolic checkpoints in human microglia or more in vivo animal experiments, and may expand to the effects of various metabolic substrates or enzyme, such as lipids and amino acids, on the functions of microglia.

Therapeutic Potential of Bacteroides fragilis SNBF-1 as a Next-Generation Probiotic: In Vitro Efficacy in Lipid and Carbohydrate Metabolism and Antioxidant Activity

This study explores the potential of aerotolerant Bacteroides fragilis (B. fragilis) strains as next-generation probiotics (NGPs), focusing on their adaptability in the gastrointestinal environment, safety profile, and probiotic functions. From 23 healthy infant fecal samples, we successfully isolated 56 beneficial B. fragilis strains. Notably, the SNBF-1 strain demonstrated superior cholesterol removal efficiency in HepG2 cells, outshining all other strains by achieving a remarkable reduction in cholesterol by 55.38 ± 2.26%. Comprehensive genotype and phenotype analyses were conducted, including sugar utilization and antibiotic sensitivity tests, leading to the development of an optimized growth medium for SNBF-1. SNBF-1 also demonstrated robust and consistent antioxidant activity, particularly in cell-free extracts, as evidenced by an average oxygen radical absorbance capacity value of 1.061 and a 2,2-diphenyl-1-picrylhydrazyl scavenging ability of 94.53 ± 7.31%. The regulation of carbohydrate metabolism by SNBF-1 was assessed in the insulin-resistant HepG2 cell line. In enzyme inhibition assays, SNBF-1 showed significant α-amylase and α-glucosidase inhibition, with rates of 87.04 ± 2.03% and 37.82 ± 1.36%, respectively. Furthermore, the cell-free supernatant (CFS) of SNBF-1 enhanced glucose consumption and glycogen synthesis in insulin-resistant HepG2 cells, indicating improved cellular energy metabolism. This was consistent with the observation that the CFS of SNBF-1 increased the proliferation of HepG2 cells by 123.77 ± 0.82% compared to that of the control. Overall, this research significantly enhances our understanding of NGPs and their potential therapeutic applications in modulating the gut microbiome.

Glycolysis regulation in tumor-associated macrophages: Its role in tumor development and cancer treatment

Tumor-associated macrophages constitute the main cell population in the tumor microenvironment and play a crucial role in regulating the microenvironment composition. Emerging evidence has revealed that the metabolic profile determines the tumor-associated macrophage phenotype. Tumor-associated macrophage function is highly dependent on glucose metabolism, with glycolysis being the major metabolic pathway. Recent reports have demonstrated diversity in glucose flux of tumor-associated macrophages and complex substance communication with cancer cells. However, how the glucose flux in tumor-associated macrophages connects with glycolysis to influence tumor progression and the tumor microenvironment is still obscure. Moreover, while the development of single-cell sequencing technology allows a clearer and more accurate classification of tumor-associated macrophages, the metabolic profiles of tumor-associated macrophages from the perspective of single-cell omics has not been well summarized. Here, we review the current state of knowledge on glucose metabolism in tumor-associated macrophages and summarize the metabolic profiles of different tumor-associated macrophage subtypes from the perspective of single-cell omics. Additionally, we describe the current strategies targeting glycolysis in tumor-associated macrophages for cancer therapy.

A pro-death autophagy-based nanoplatform for enhancing antitumour efficacy with improved immune responses

Due to the pro-survival effect of mild autophagy, the therapeutic effect of chemo-immunotherapy is unsatisfactory. In addition, the adverse tumour microenvironment (TME), including the lack of antigen presentation, the deficiency of oxygen supply and immunosuppressive cells, results in immune escape and metastasis. Herein, a novel nanoplatform (CS-3BP/PA@DOX) based on the autophagy cascade is proposed for the first time to deliver the chemotherapeutic doxorubicin (DOX) and respiration inhibitor 3-bromopyruvic acid (3BP) to overcome the above obstacles. CS-3BP/PA@DOX exerts a synergistic therapeutic effect to initiate pro-death autophagy and facilitate the antigen presentation process by combining DOX chemotherapy and starvation therapy with 3BP. Additionally, CS-3BP/PA@DOX remodelled the immunosuppressive TME by alleviating hypoxia, damaging dense ECM, and downregulating PD-L1 to enhance antitumour immunity. 3BP was found to promote GSH depletion by inhibiting respiration for the first time, which reduces the chemical resistance of cancer and increases the sensitivity of cells to ROS, providing a new therapeutic direction of 3BP for antitumour treatment. Collectively, this study offers an opportunity to magnify pro-death autophagy, augment antitumour efficacy, facilitate anti-metastatic effects, and boost immune responses.

Ubiquitination plays an important role during the formation of chicken primordial germ cells

As an important posttranslational modification, ubiquitination plays an important role in regulating protein homeostasis in eukaryotic cells. In our previous studies, both the transcriptome and proteome suggested that ubiquitination is involved in the formation of chicken primordial germ cells (PGCs). Here, affinity enrichment combined with liquid chromatography-tandem mass spectrometry (MS/MS) was used to analyze the ubiquitome during the differentiation from embryonic stem cells to PGCs, and we identify that 724 lysine ubiquitinated sites were up-regulated in 558 proteins and 138 lysine ubiquitinated sites were down-regulated in 109 proteins. Furthermore, GO and KEGG enrichment analysis showed that ubiquitination regulates key proteins to participate in the progression of key events related to PGC formation and the transduction of key signals such as Wnt, MAPK, and insulin signals, followed by the detailed explanation of the specific regulatory mechanism of ubiquitination through the combined proteome and ubiquitome analysis. Moreover, both the activation and inhibition of neddylation were detrimental to the maintenance of the biological characteristics of PGCs, which also verified the importance of ubiquitination. In conclusion, this study provides a global view of the ubiquitome during the formation of PGCs by label-free quantitative ubiquitomics, which lays a theoretical foundation for the formation mechanism and specific application of chicken PGCs.

Fucoxanthin Abrogates Ionizing Radiation-Induced Inflammatory Responses by Modulating Sirtuin 1 in Macrophages

Ionizing radiation (IR) triggers an overproduction of reactive oxygen species (ROS), disrupting the normal function of both immune and metabolic systems, leading to inflammation and metabolic disturbances. To address the pressing requirement for protection against IR, fucoxanthin (FX), a naturally occurring compound extracted from algae, was utilized as an efficient radioprotective agent in macrophages. In this study, we cultured murine RAW 264.7 macrophages and treated them with FX, along with agents influencing the activity of sirtuin 1 (SIRT1) and estrogen receptor α (ERα), to investigate their impact on IR-induced cellular responses. FX significantly attenuated IR-induced upregulation of pro-inflammatory genes (Il1b, Tnf, and Ccl2) and inhibited macrophage polarization toward the pro-inflammatory M1 phenotype. Additionally, FX regulated IR-induced metabolic genes mediating glycolysis and mitochondrial biogenesis. The ability of FX to mitigate IR-induced inflammation and glycolysis was ascribed to the expression and activity of SIRT1 and ERα in macrophages. This study not only uncovers the underlying mechanisms of FX's radioprotective properties but also highlights its potential as a protective agent against the detrimental effects of IR, thus offering new opportunities for enhancing radiation protection in the future.

A Novel LncRNA MASCC1 Regulates the Progression and Metastasis of Head and Neck Squamous Cell Carcinoma by Sponging miR-195

The altered expression of long noncoding RNAs (lncRNAs) is associated with human carcinogenesis. We performed a high-throughput analysis of lncRNA expression in strictly selected pairs of metastatic head and neck squamous cell carcinoma (HNSCC) and non-metastatic HNSCC samples. We identified a novel lncRNA, which was highly expressed in metastatic HNSCC, named Metastasis Associated Squamous Cell Carcinoma 1 (MASCC1), for further study. Using qRT-PCR, we further compared MASCC1 expression in 60 HNSCC samples. The results show that high expression of MASCC1 in patients with HNSCC was related to poor prognosis. In vitro, MASCC1 knockdown (KD) inhibited HNSCC proliferation, migration, invasion, and tumor sphere formation, while promoting apoptosis. In vivo, MASCC1 KD inhibited HNSCC growth and lymph node metastasis. Mechanistically, MASCC1 acted as a competing endogenous RNA (ceRNA) by binding to miR-195, subsequently regulating the expression of Cyclin D1, BCL-2, and YAP1. Moreover, miR-195 overexpression rescued the effects of MASCC1 on the biological behaviors of HNSCC. Taken together, our results suggest that MASCC1 is a novel oncogene that can predict the prognosis of patients with HNSCC and is a potential therapeutic target for HNSCC intervention.

Preadipocytes in human granulation tissue: role in wound healing and response to macrophage polarization

BACKGROUND

Chronic non-healing wounds pose a global health challenge. Under optimized conditions, skin wounds heal by the formation of scar tissue. However, deregulated cell activation leads to persistent inflammation and the formation of granulation tissue, a type of premature scar tissue without epithelialization. Regenerative cells from the wound periphery contribute to the healing process, but little is known about their cellular fate in an inflammatory, macrophage-dominated wound microenvironment.

METHODS

We examined CD45-/CD31-/CD34+ preadipocytes and CD68+ macrophages in human granulation tissue from pressure ulcers (n=6) using immunofluorescence, immunohistochemistry, and flow cytometry. In vitro, we studied macrophage-preadipocyte interactions using primary human adipose-derived stem cells (ASCs) exposed to conditioned medium harvested from IFNG/LPS (M1)- or IL4/IL13 (M2)-activated macrophages. Macrophages were derived from THP1 cells or CD14+ monocytes. In addition to confocal microscopy and flow cytometry, ASCs were analyzed for metabolic (OXPHOS, glycolysis), morphological (cytoskeleton), and mitochondrial (ATP production, membrane potential) changes. Angiogenic properties of ASCs were determined by HUVEC-based angiogenesis assay. Protein and mRNA levels were assessed by immunoblotting and quantitative RT-PCR.

RESULTS

CD45-/CD31-/CD34+ preadipocytes were observed with a prevalence of up to 1.5% of total viable cells in human granulation tissue. Immunofluorescence staining suggested a spatial proximity of these cells to CD68+ macrophages in vivo. In vitro, ASCs exposed to M1, but not to M2 macrophage secretome showed a pro-fibrotic response characterized by stress fiber formation, elevated alpha smooth muscle actin (SMA), and increased expression of integrins ITGA5 and ITGAV. Macrophage-secreted IL1B and TGFB1 mediated this response via the PI3K/AKT and p38-MAPK pathways. In addition, ASCs exposed to M1-inflammatory stress demonstrated reduced migration, switched to a glycolysis-dominated metabolism with reduced ATP production, and increased levels of inflammatory cytokines such as IL1B, IL8, and MCP1. Notably, M1 but not M2 macrophages enhanced the angiogenic potential of ASCs.

CONCLUSION

Preadipocyte fate in wound tissue is influenced by macrophage polarization. Pro-inflammatory M1 macrophages induce a pro-fibrotic response in ASCs through IL1B and TGFB1 signaling, while anti-inflammatory M2 macrophages have limited effects. These findings shed light on cellular interactions in chronic wounds and provide important information for the potential therapeutic use of ASCs in human wound healing.

Functional Organization of Glycolytic Metabolon on Mitochondria

Glucose, the primary cellular energy source, is metabolized through glycolysis initiated by the rate-limiting enzyme Hexokinase (HK). In energy-demanding tissues like the brain, HK1 is the dominant isoform, primarily localized on mitochondria, crucial for efficient glycolysis-oxidative phosphorylation coupling and optimal energy generation. This study unveils a unique mechanism regulating HK1 activity, glycolysis, and the dynamics of mitochondrial coupling, mediated by the metabolic sensor enzyme O-GlcNAc transferase (OGT). OGT catalyzes reversible O-GlcNAcylation, a post-translational modification, influenced by glucose flux. Elevated OGT activity induces dynamic O-GlcNAcylation of HK1's regulatory domain, subsequently promoting the assembly of the glycolytic metabolon on the outer mitochondrial membrane. This modification enhances HK1's mitochondrial association, orchestrating glycolytic and mitochondrial ATP production. Mutations in HK1's O-GlcNAcylation site reduce ATP generation, affecting synaptic functions in neurons. The study uncovers a novel pathway that bridges neuronal metabolism and mitochondrial function via OGT and the formation of the glycolytic metabolon, offering new prospects for tackling metabolic and neurological disorders.

mRNA location and translation rate determine protein targeting to dual destinations

Numerous proteins are targeted to two or multiple subcellular destinations where they exert distinct functional consequences. The balance between such differential targeting is thought to be determined post-translationally, relying on protein sorting mechanisms. Here, we show that mRNA location and translation rate can also determine protein targeting by modulating protein binding to specific interacting partners. Peripheral localization of the NET1 mRNA and fast translation lead to higher cytosolic retention of the NET1 protein by promoting its binding to the membrane-associated scaffold protein CASK. By contrast, perinuclear mRNA location and/or slower translation rate favor nuclear targeting by promoting binding to importins. This mRNA location-dependent mechanism is modulated by physiological stimuli and profoundly impacts NET1 function in cell motility. These results reveal that the location of protein synthesis and the rate of translation elongation act in coordination as a "partner-selection" mechanism that robustly influences protein distribution and function.

Hexokinase dissociation from mitochondria promotes oligomerization of VDAC that facilitates NLRP3 inflammasome assembly and activation

NLRP3 inflammasome activation is a highly regulated process for controlling secretion of the potent inflammatory cytokines IL-1β and IL-18 that are essential during bacterial infection, sterile inflammation, and disease, including colitis, diabetes, Alzheimer's disease, and atherosclerosis. Diverse stimuli activate the NLRP3 inflammasome, and unifying upstream signals has been challenging to identify. Here, we report that a common upstream step in NLRP3 inflammasome activation is the dissociation of the glycolytic enzyme hexokinase 2 from the voltage-dependent anion channel (VDAC) in the outer membrane of mitochondria. Hexokinase 2 dissociation from VDAC triggers activation of inositol triphosphate receptors, leading to release of calcium from the ER, which is taken up by mitochondria. This influx of calcium into mitochondria leads to oligomerization of VDAC, which is known to form a macromolecule-sized pore in the outer membranes of mitochondria that allows proteins and mitochondrial DNA (mtDNA), often associated with apoptosis and inflammation, respectively, to exit the mitochondria. We observe that VDAC oligomers aggregate with NLRP3 during initial assembly of the multiprotein oligomeric NLRP3 inflammasome complex. We also find that mtDNA is necessary for NLRP3 association with VDAC oligomers. These data, together with other recent work, help to paint a more complete picture of the pathway leading to NLRP3 inflammasome activation.