Lactate metabolism in human health and disease

L- and D-Lactate: unveiling their hidden functions in disease and health

Lactate, once considered a mere byproduct of anaerobic metabolism, is now recognized as a critical signaling molecule with diverse roles in physiology and pathology. There are two stereoisomers of lactate: L- and D-lactate. Recent studies have shown that disruptions in these two lactate stereoisomers have distinct effects on health and disease. L-lactate is central to glycolysis and energy transfer through the Cori cycle but also acts as the dominant lactylation isomer induced by glycolysis, influencing metabolism and cell survival. Although less studied, D-lactate is linked to metabolic disorders and plays a role in mitochondrial dysfunction and oxidative stress. This review focuses on both L- and D-lactate and examines their biosynthesis, transport, and expanding roles in physiological and pathological processes, particularly their functions in cancer, immune regulation, inflammation, neurodegeneration and other diseases. Finally, we assess the therapeutic prospects of targeting lactate metabolism, highlighting emerging strategies for intervention in clinical settings. Our review synthesizes the current understanding of L- and D-lactate, offering insights into their potential as targets for therapeutic innovation.

Reprogramming of Thyroid Cancer Metabolism: from Mechanism to Therapeutic Strategy

Thyroid cancer as one of the most prevalent malignancies of endocrine system, has raised public concern and more research on its mechanism and treatment. And metabolism-based therapies have advanced rapidly, for the exclusive metabolic profiling of thyroid cancer. In thyroid cancer cells, plenty of metabolic pathways are reprogrammed to accommodate tumor microenvironment. In this review, we initiatively summarize recent progress in the full-scale thyroid cancer metabolic rewiring and the interconnection of various metabolites. We also discuss the efficacy and prospect of metabolic targeted detection as well as therapy. Comprehending metabolic mechanism and characteristics of thyroid cancer roundly will be highly beneficial to managing individual patients.

Lactylation and Central Nervous System Diseases

As the final product of glycolysis, lactate serves as an energy substrate, metabolite, and signaling molecule in various diseases and mediates lactylation, an epigenetic modification that occurs under both physiological and pathological conditions. Lactylation is a crucial mechanism by which lactate exerts its functions, participating in vital biological activities such as glycolysis-related cellular functions, macrophage polarization, and nervous system regulation. Lactylation links metabolic regulation to central nervous system (CNS) diseases, such as traumatic brain injury, Alzheimer's disease, acute ischemic stroke, and schizophrenia, revealing the diverse functions of lactylation in the CNS. In the future, further exploration of lactylation-associated enzymes and proteins is needed to develop specific lactylation inhibitors or activators, which could provide new tools and strategies for the treatment of CNS diseases.

Single-cell analysis identifies MKI67+ microglia as drivers of neovascularization in proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is among the primary causes of blindness in individuals with diabetes. Elevated lactate levels have been identified as a critical biomarker associated with the prognosis of PDR. While significant lactate accumulation has been observed in the vitreous fluid of PDR patients, the detailed pathways through which lactate impacts pathological neovascularization remain insufficiently elucidated.

METHODS

The study employed single-cell RNA sequencing (scRNA-seq) to identify and characterize lactate-associated cell type in PDR patients. Key gene expression profiles and molecular pathways associated with lactate metabolism were analyzed. In vitro experiments were conducted using microglial cell cultures treated with high-glucose conditions (50 mM) to assess the induction of lactate metabolism-related genes. Additionally, an oxygen-induced retinopathy (OIR) mouse model was used to evaluate the impact of abemaciclib, an FDA-approved proliferation inhibitor, on retinal neovascularization.

RESULTS

To the best of our knowledge, this investigation is the first to delineate a novel microglial subset, designated as MKI67+ microglia, distinguished by robust upregulation of genes implicated in lactate metabolic processes and proliferation, such as MKI67, PARK7 and LDHA, as well as a pronounced enrichment of glycolysis-associated molecular pathways. This unique cell type promotes angiogenesis by interacting with endothelial cells via secreted phosphoprotein 1 (SPP1)-Integrin alpha 4 (ITGA4) signaling. In vitro experiments have shown the use of 50 mM high glucose to simulate microglia in PDR environment and observe its promotion of vascular proliferation. In the in vivo OIR model, treatment with abemaciclib, a FDA-approved proliferation inhibitor, significantly reduced neovascularization.

CONCLUSION

The identification of MKI67+ microglia as a cell type strongly associated with lactate metabolism provides a novel perspective on the mechanisms underlying PDR onset. These findings expand our understanding of the cellular and metabolic dynamics in PDR, emphasizing potential implications for targeted therapeutic interventions.

Dysregulation of lipid metabolism, energy production, and oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome, Gulf War Syndrome and fibromyalgia

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Gulf War Syndrome (GWS), and Fibromyalgia (FM) are complex, chronic illnesses with overlapping clinical features. Symptoms that are reported across these conditions include post-exertional malaise (PEM), fatigue, and pain, yet the etiology of these illnesses remains largely unknown. Diagnosis is challenging in patients with these conditions as definitive biomarkers are lacking; patients are required to meet clinical criteria and often undergo lengthy testing to exclude other conditions, a process that is often prolonged, costly, and burdensome for patients. The identification of reliable validated biomarkers could facilitate earlier and more accurate diagnosis and drive the development of targeted pharmacological therapies that might address the underlying pathophysiology of these diseases. Major driving forces for biomarker identification are the advancing fields of metabolomics and proteomics that allow for comprehensive characterization of metabolites and proteins in biological specimens. Recent technological developments in these areas enable high-throughput analysis of thousands of metabolites and proteins from a variety of biological samples and model systems, that provides a powerful approach to unraveling the metabolic phenotypes associated with these complex diseases. Emerging evidence suggests that ME/CFS, GWS, and FM are all characterized by disturbances in metabolic pathways, particularly those related to energy production, lipid metabolism, and oxidative stress. Altered levels of key metabolites in these pathways have been reported in studies highlighting potential common biochemical abnormalities. The precise mechanisms driving altered metabolic pathways in ME/CFS, GWS, and FM remain to be elucidated; however, the elevated oxidative stress observed across these illnesses may contribute to symptoms and offer a potential target for therapeutic intervention. Investigating the mechanisms, and their role in the disease process, could provide insights into disease pathogenesis and reveal novel treatment targets. As such, comprehensive metabolomic and proteomic analyses are crucial for advancing the understanding of these conditions in-order to identify both common, and unique, metabolic alterations that could serve as diagnostic markers or therapeutic targets.

Lactate promotes premature aging of preeclampsia placentas through histone lactylation-regulated GADD45A

BACKGROUND

Premature placental aging has been linked to preeclampsia (PE), with lactate identified as a promoter of cellular senescence in various cell types. In this study, we explored the role and underlying mechanisms of lactate in driving premature placental aging associated with PE.

METHODS

To evaluate senescence markers in placental samples or trophoblast cells, we conducted SA-β-Gal staining, western blotting, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and immunofluorescence assays. SiRNA transfection was used to reduce GADD45A expression in HTR-8/SVneo cells exposed to lactate. Additionally, chromatin immunoprecipitation-qPCR (ChIP-qPCR) was used to analyze histone lactylation at the GADD45A promoter region.

RESULTS

SA-β-Gal staining indicated a significant increase in senescent cell proportions in placentas from PE patients compared to controls. Treatment with lactate enhanced senescence in trophoblast cells, leading to an increase in P16 expression. RNA sequencing analysis showed that genes differentially expressed in lactate-treated cells were involved in pathways linked to cellular senescence. Additionally, lactate augmented GADD45A expression and increased histone lactylation at its promoter region, while knocking down GADD45A in trophoblast cells mitigated the senescence induced by lactate.

CONCLUSIONS

Lactate promotes trophoblast senescence through epigenetic upregulation of GADD45A expression, offering fresh perspectives on the molecular mechanisms and potential treatment targets for PE.

Fructose-Driven glycolysis supports synaptic function in subterranean rodent - Gansu Zokor (Eospalax cansus)

Several studies indicate that fructose can be used as an energy source for subterranean rodents. However, how subterranean rodents utilize fructose metabolism with no apparent physiological drawbacks remains poorly understood. In the present study, we measured field excitatory postsynaptic potentials (fEPSPs) in hippocampal slices from Gansu zokor and SD rats hippocampi before and 60 min after replacement of 10 mM glucose in the artificial cerebrospinal fluid (ACSF) with 10 mM fructose (gassed with 95 % O2 and 5 % CO2). Subsequently, we performed transcriptome analysis on Gansu zokor brains incubated with ACSF containing 10 mM fructose and determined the contents of fructose, lactate, ATP, and UA. Whole brain RNA and proteins were extracted to detect the transcriptional levels of Glut5, Khk, Aldoc, and Cs and the translational levels of GLUT5, CS, NRF2, and c-FOS. The results showed that Gansu zokor brains exhibit higher levels of GLUT5 protein and Khk mRNA levels than SD rats to facilitate fructose uptake and metabolism, resulting in increased fructose, ATP, and lactate content in the brain during fructose incubation. Stable UA levels during fructose metabolism reduce the risk of oxidative stress and neuroinflammation, and activation of the Nrf2 pathway increases downstream antioxidant capacity, thereby reducing brain damage. Persistent fEPSP signaling suggests that fructose supports excitatory synaptic transmission in the CA1 region of the hippocampus of the Gansu zokor but leads to hippocampal dysfunction in SD rats. The unique insights about fructose metabolism in the brain of Gansu zokor obtained in our study will be useful for further studies on the evolution of subterranean rodents.

The emerging role of glycolysis and immune evasion in ovarian cancer

Ovarian cancer (OC) is one of the three most common malignant tumors of the female reproductive system, with the highest mortality rate among gynecologic malignancies. Like other tumors, OC cells undergo metabolic reprogramming phenomenon and convert glucose metabolism into "aerobic glycolysis" and generate a high concentration of lactate, i.e., the "Warburg effect", which provides a large amount of energy and corresponding intermediary metabolites for their survival, reproduction and metastasis. Numerous studies have shown that targeted inhibition of aerobic glycolysis and lactate metabolism is a promising strategy to enhance the sensitivity of cancer cells to immunotherapy. Therefore, this review summarizes the metabolic features of glycolysis in OC cells and highlights how abnormal lactate concentration affects the differentiation, metabolism, and function of infiltrating immune cells, which contributes to immunosuppression, and how targeted inhibition of this phenomenon may be a potential strategy to enhance the therapeutic efficacy of OC.

Current and future perspectives of lysine lactylation in cancer

Lactate, a glycolytic intermediate, has a crucial role in cancer metabolism and microenvironment remodeling. Recently, researchers found that lactate mediates lysine lactylation, a novel protein post-translational modification (PTM). Here, we summarize the mechanism and role of lysine lactylation in cancer, and discuss the potential of targeting lysine lactylation in cancer therapy.

Macro/Microgel-Encapsulated, Biofilm-Armored Living Probiotic Platform for Regenerating Bacteria-Infected Diabetic Wounds

Infectious diabetic wounds pose an arduous threat to contemporary healthcare. The combination of refractory biofilms, persistent inflammation, and retarded angiogenesis can procure non-unions and life-threatening complications, calling for advanced therapeutics potent to orchestrate anti-infective effectiveness, benign biocompatibility, pro-reparative immunomodulation, and angiogenic regeneration. Herein, embracing the emergent "living bacterial therapy" paradigm, a designer probiotic-in-hydrogel wound dressing platform is demonstrated. The platform is constructed employing a "macrogel/microgel/biofilm" hierarchical encapsulation strategy, with Lactobacillus casei as the model probiotic. Alginate gels, in both macro and micro forms, along with self-produced probiotic biofilms, served as encapsulating agents. Specifically, live probiotics are enclosed within alginate microspheres, embedded into an alginate bulk matrix, and cultivated to facilitate biofilm self-encasing. This multiscale confinement protected the probiotics and averted their inadvertent escape, while enabling sustained secretion, proper reservation, and localized delivery of therapeutically active probiotic metabolites, such as lactic acid. The resulting biosystem, as validated in vitro/ovo/vivo, elicited well-balanced antibacterial activities and biological compatibility, alongside prominent pro-healing, vasculogenic and anti-inflammatory potencies, thus accelerating the regeneration of infected full-thickness excisional wounds in diabetic mice. Such multiple encapsulation-engineered "all-in-one" probiotic delivery tactic may shed new light on the safe and efficient adoption of live bacteria for treating chronic infectious diseases.

Correlation of Arterial Lactate and pH With the Immediate Outcome of Term Asphyxiated Neonates

INTRODUCTION

Perinatal asphyxia is a significant cause of neonatal morbidity and mortality. Early identification of neonates at risk for adverse outcomes is crucial for timely intervention. This study aimed to evaluate the prognostic value of arterial lactate and pH levels in predicting immediate clinical outcomes in term asphyxiated neonates. Additionally, the study explored the potential association between elevated lactate levels and hearing impairment.

METHODS

This observational cross-sectional study was conducted at a tertiary care center in Bhopal, India. A total of 100 term neonates with birth asphyxia were enrolled. Neonates admitted within six hours of birth had their arterial lactate and pH levels measured within the first hour of neonatal intensive care unit (NICU) admission. Survival rates, neurological outcomes at discharge, and hearing assessment of asphyxiated neonates through otoacoustic emissions (OAE) were the primary and secondary objectives. Statistical analysis involved Pearson's correlation and receiver operating characteristic (ROC) curves to determine optimal pH and lactate thresholds for predicting adverse outcomes.

RESULTS

A lactate threshold of 6.2 mmol/L was predictive of neurological abnormalities (area under the curve (AUC) 0.85, sensitivity 76%, specificity 79%), while a threshold of 10 mmol/L was associated with increased mortality (AUC 0.77, sensitivity 59%, specificity 88%). pH levels <7.2 were linked to a higher risk of death (AUC 0.79, sensitivity 71%, specificity 77%). pH levels below 7.3 were associated with a greater risk of neurologically abnormal neonates (AUC 0.78, sensitivity 83%, specificity 62%). Neonates who failed OAE screening had significantly higher lactate levels compared to those who passed, suggesting an association between higher lactate values and hearing impairment in asphyxiated neonates. The median (IQR) lactate levels for the B/L Pass and B/L Refer groups were 4.3 (3.1, 6.8) and 7.4 (6.3, 10.3), respectively.

CONCLUSION

Arterial lactate and pH are valuable biomarkers for the early prediction of neurological abnormalities, mortality, and hearing impairment in term asphyxiated neonates. Integrating these measurements into neonatal care protocols may enhance risk stratification and guide early interventions.

Unveiling lactylation modification: A new hope for cancer treatment

This review article delves into the multifaceted role of lactylation modification in antitumor therapy, revealing the complex interplay between lactylation modification and the tumor microenvironment (TME), metabolic reprogramming, gene expression, and immunotherapy. As an emerging epigenetic modification, lactylation has a significant impact on the metabolic pathways of tumor cells, immune evasion, gene expression regulation, and sensitivity to chemotherapy drugs. Studies have shown that lactylation modification significantly alters the development and therapeutic response of tumors by affecting metabolites in the TME, immune cell functions, and signaling pathways. In the field of immunotherapy, the regulatory role of lactylation modification provides a new perspective and potential targets for tumor treatment, including modulating the sensitivity of tumors to immunotherapy by affecting the expression of immune checkpoint molecules and the infiltration of immune cells. Moreover, research progress on lactylation modification in various types of tumors indicates that it may serve as a biomarker to predict patients' responses to chemotherapy and immunotherapy. Overall, research on lactylation modification provides a theoretical foundation for the development of new tumor treatment strategies and holds promise for improving patient prognosis and quality of life. Future research will further explore the application potential of lactylation modification in tumor therapy and how to improve treatment efficacy by targeting lactylation modification.

Bioinformatics Identification of Lactate-Associated Genes in Hepatocellular Carcinoma: G6PD's Role in Immune Modulation

BACKGROUND

Hepatocellular carcinoma (HCC) is a major global health issue, with poor prognosis often associated with dysregulated metabolic pathways, especially lactate metabolism. This study explored the prognostic significance of lactate-associated genes in HCC and their potential as therapeutic targets.

METHODS

We analyzed RNA-seq and clinical data from 374 patients with HCC from The Cancer Genome Atlas (TCGA) database. Using Cox regression, LASSO analysis, and Kaplan-Meier survival curves, we identified key lactate-associated genes associated with patient outcomes. Functional validations, including Western blot, flow cytometry, and molecular docking studies, were performed to confirm the biological impact of these genes.

RESULTS

G6PD, IK, and CALML5 were identified as significant prognostic markers for HCC. A prognostic model was developed that effectively stratified patients into risk groups, which correlated with survival. G6PD's role in immune modulation and its potential as a drug target were validated through biochemical assays and computational analyses. Functional assays in HepG2 cells confirmed that alterations in G6PD expression affect T cell activity, with knockdown enhancing IFN-γ production and overexpression inhibiting it, demonstrating G6PD's role in immune evasion.

CONCLUSIONS

This study establishes lactate metabolism genes, particularly G6PD, as key prognostic markers in HCC. The validation of G6PD's immunomodulatory effects further supports its potential as a therapeutic target for strategies aimed at enhancing immune surveillance and treatment outcomes in HCC.

The role of lactate and lactylation in ischemic cardiomyopathy: Mechanisms and gene expression

Ischemic cardiomyopathy (ICM) is a significant global public health issue, with its pathophysiology encompassing atherosclerotic plaque formation, thrombosis, hypoperfusion, ischemic cell death, and left ventricular remodeling. Lactate is not only regarded as an energy metabolite but also acts as a signaling molecule that influences various physiological processes, regulating metabolism and muscle contraction. Lactylation, an emerging epigenetic modification, affects protein functionality and gene expression through the P300 enzyme. In ICM, lactate accumulation leads to pH imbalance and myocardial cell dysfunction, impacting cellular signaling. This paper will analyze the role of lactylation in ICM, focusing on coronary artery disease (ASCVD) and myocardial infarction (MI). It will also explore the differential expression and immunological characteristics of lactylation-related genes in normal and ICM tissues, providing potential targets for future research.

Machine Learning-Based Glycolipid Metabolism Gene Signature Predicts Prognosis and Immune Landscape in Oesophageal Squamous Cell Carcinoma

Using machine learning approaches, we developed and validated a novel prognostic model for oesophageal squamous cell carcinoma (ESCC) based on glycolipid metabolism-related genes. Through integrated analysis of TCGA and GEO datasets, we established a robust 15-gene signature that effectively stratified patients into distinct risk groups. This signature demonstrated superior prognostic value and revealed significant associations with immune infiltration patterns. High-risk patients exhibited reduced immune cell infiltration, particularly in B cells and NK cells, alongside increased tumour purity. Single-cell RNA sequencing analysis uncovered unique cellular composition patterns and enhanced interaction intensities in the high-risk group, especially within epithelial and smooth muscle cells. Functional validation confirmed MECP2 as a promising therapeutic target, with its knockdown significantly inhibiting tumour progression both in vitro and in vivo. Drug sensitivity analysis identified specific therapeutic agents showing potential efficacy for high-risk patients. Our study provides both a practical prognostic tool and novel insights into the relationship between glycolipid metabolism and tumour immunity in ESCC, offering potential strategies for personalised treatment.

Unveiling the tissue-specific landscape of nuclear-encoded mitochondrial genes involved in amino acid metabolism in buffalo

Mitochondria play a pivotal role in energy production, metabolism, and cellular signaling, serving as key regulators of cellular functions, including differentiation and tissue-specific adaptation. The interplay between mitochondria and the nucleus is crucial for coordinating these processes, particularly through the supply of metabolites for epigenetic modifications that facilitate nuclear-mitochondrial interactions. To investigate tissue-specific mitochondrial adaptations at the molecular level, we conducted RNA sequencing data analyses of kidney, heart, brain, and ovary tissues of female buffaloes, focusing on variations in mitochondrial gene expression related to amino acid metabolism. Our analysis identified 82 nuclear-encoded mitochondrial transcripts involved in amino acid metabolism, with significant differential expression patterns across all tissues. Notably, the heart, brain, and kidney-tissues with higher energy demands-exhibited elevated expression levels compared to the ovary. The kidney displayed unique gene expression patterns, characterized by up-regulation of genes involved in glyoxylate metabolism and amino acid catabolism. In contrast, comparative analysis of the heart and kidney versus the brain revealed shared up-regulation of genes associated with fatty acid oxidation. Gene ontology and KEGG pathway analyses confirmed the enrichment of genes in pathways related to amino acid degradation and metabolism. These findings highlight the tissue-specific regulation of mitochondrial gene expression linked to amino acid metabolism, reflecting mitochondrial adaptations to the distinct metabolic and energy requirements of different tissues in buffalo. Importantly, our results underscore the relevance of mitochondrial adaptations not only for livestock health but also for understanding metabolic disorders in humans. By elucidating the molecular mechanisms of mitochondrial function and their tissue-specific variations, this study provides insights that could inform breeding strategies for enhanced livestock productivity and contribute to therapeutic approaches for human metabolic diseases. Thus, our findings illustrate how mitochondria are specialized in a tissue-specific manner to optimize amino acid utilization and maintain cellular homeostasis, with implications for both animal welfare and human health.

Atrazine's effects on mammalian physiology

Atrazine is a chlorotriazine herbicide that is one of the most widely used herbicides in the USA and the world. For over 60 years atrazine has been used on major crops including corn, sorghum, and sugarcane to control broadleaf and grassy weed emergence and growth. Atrazine has exerted a major economic and environmental impact over that time, resulting in reduced production costs and increased conservation tillage practices. However, widespread use and a long half-life led to a high prevalence of atrazine in the environment. Indeed, atrazine is the most frequent herbicide contaminant detected in water sources in the USA. Due to its almost ubiquitous presence and questions regarding its safety, atrazine has been well-studied. First reported to affect reproduction with potential disruptive effects which were later linked to the immune system, cancer, stress response, neurological disorders, and cardiovascular ailments in experimental models. Atrazine impact on multiple interwoven systems broadens the significance of atrazine exposure. The endeavor to uncover the mechanisms underlying atrazine-induced dysfunction in mammals is ongoing, with new genetic and pharmacological targets being reported. This review aims to summarize the prominent effects of atrazine on mammalian physiology, primarily focusing on empirical studies conducted in lab animal models and establish correlations with epidemiological human studies when relevant. In addition, current common patterns of toxicity and potential underlying mechanisms of atrazine action will be examined.

Insights into the Activation Mechanism of HCA1, HCA2, and HCA3

Hydroxy-carboxylic acid receptors HCA1, HCA2, and HCA3 can be activated by important intermediates of energy metabolism. Despite the research focusing on HCA2, its clinical application has been limited by adverse effects. Therefore, the role of HCA1 as a promising target for the treatment of lipolysis warrants further exploration. As HCAs exhibit high similarity when activated with diverse selective agonists, a conserved yet unique activation mechanism for HCAs remains undisclosed. Herein, we unveil the cryo-electron microscopy structures of the 3,5-DHBA-HCA1-Gi signaling complex, the acifran- and MK6892-bound HCA2-Gi signaling complexes, and the acifran-HCA3-Gi signaling complex. Comparative analysis across HCAs reveals key residues in HCA1 contributing to the stabilization of the ligand-binding pocket. Furthermore, chimeric complexes and mutational analyses identify residues that are pivotal for HCA2 and HCA3 selectivity. Our findings elucidate critical structural insights into the mechanisms of ligand recognition and activation within HCA1 and broaden our comprehension of ligand specificity binding across the HCA family.

Lactylation of PLBD1 Facilitates Brain Injury Induced by Ischemic Stroke

BACKGROUND

Ischemic stroke is a prevalent global condition and its associated brain damage poses a significant threat to patient survival and outcomes. The underlying mechanisms of ischemic stroke-induced brain injury remain elusive, necessitating further investigation.

METHODS

Ischemic stroke models were established using middle cerebral artery occlusion (MCAO) in animals and oxygen-glucose deprivation and reperfusion (OGD-R) in cells. Phospholipase B domain-containing protein 1 (PLBD1) expression in these models was assessed via western blotting analysis, reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR), and cell immunofluorescence. A comprehensive evaluation, incorporating cellular lactate dehydrogenase (LDH) release assays, glycolysis metabolism kits, RT-qPCR, western blotting, triphenyl tetrazolium chloride (TTC) staining, neurological scoring, brain tissue water content measurement, and creatine kinase-MB (CK-MB) analysis, was conducted to determine the impact of PLBD1 on brain injury. Potential lactylation sites in PLBD1 were predicted using the DeepKla database, with western blotting and co-immunoprecipitation (Co-IP) confirming the lactylation site.

RESULTS

PLBD1 was significantly upregulated in the brain tissue of MCAO animal models and OGD-R-treated cells. PLBD1 knockdown markedly mitigated OGD-R-induced cellular injury, suppressed glycolysis in vitro, and reversed MCAO-induced brain damage in vivo. Furthermore, lactylation at the K155 site of PLBD1 enhanced its expression in response to elevated lactate levels following OGD-R treatment. These results indicated that the upregulation of PLBD1 via K155 site lactylation plays a pivotal role in exacerbating ischemic stroke-induced brain damage.

CONCLUSION

Targeting the lactate/PLBD1 axis presents a promising therapeutic strategy for ischemic stroke management.

The contemporary role of lactate in exercise physiology and exercise prescription - a review of the literature

Lactate is a key molecule in exercise metabolism. In the last two decades, there has been a revolution in the understanding of its role - from a byproduct of hypoxic muscles to a major energy resource and a signaling molecule - 'lactormone'. The aim of this review is to compile all the up-to-date information that is available on the general metabolism of lactate, but also the specific use that exercise physiologists, coaches, and athletes can get out of lactate measurements, lactate-based training zones, and periodization of training sessions. Since the revolution in the understanding of lactate's role in normal metabolism and disease in the late 20th century, more evidence has been assembled regarding the specific part it plays in exercise. From the vast body of knowledge, the researchers developed the concept of training intensity distribution into zones according to the level of blood lactate. The end goal of training to a specific lactate level or 'threshold' is the increased adaptation to specific training stimuli and ultimately better performance, which has been backed up by the achievements of numerous athletes training according to this concept.

Sauchinone Ameliorates Senescence Through Reducing Mitochondrial ROS Production

One of the major causes of senescence is oxidative stress caused by ROS, which is mainly generated from dysfunctional mitochondria. Strategies to limit mitochondrial ROS production are considered important for reversing senescence, but effective approaches to reduce them have not yet been developed. In this study, we screened the secondary metabolites that plants produce under oxidative stress and discovered sauchinone as a potential candidate. Sauchinone induced mitochondrial function recovery, enabling efficient electron transport within the electron transport chain (ETC). This led to a decrease in ROS production, a byproduct of inefficient electron transport. The reduction in ROS by sauchinone rejuvenated senescence-associated phenotypes. To understand the underlying mechanism by which sauchinone rejuvenates senescence, we carried out RNA sequencing and found VAMP8 as a key gene. VAMP8 was downregulated by sauchinone. Knockdown of VAMP8 decreased mitochondrial ROS levels and subsequently rejuvenated mitochondrial function, which was similar to the effect of sauchinone. Taken together, these studies revealed a novel mechanism by which sauchinone reduces mitochondrial ROS production by regulating mitochondrial function and VAMP8 expression. Our results open a new avenue for aging research to control senescence by regulating mitochondrial ROS production.

Advances in Wearable Biosensors for Wound Healing and Infection Monitoring

Wound healing is a complicated biological process that is important for restoring tissue integrity and function after injury. Infection, usually due to bacterial colonization, significantly complicates this process by hindering the course of healing and enhancing the chances of systemic complications. Recent advances in wearable biosensors have transformed wound care by making real-time monitoring of biomarkers such as pH, temperature, moisture, and infection-related metabolites like trimethylamine and uric acid. This review focuses on recent advances in biosensor technologies designed for wound management. Novel sensor architectures, such as flexible and stretchable electronics, colorimetric patches, and electrochemical platforms, enable the non-invasive detection of changes associated with wounds with high specificity and sensitivity. These are increasingly combined with AI and analytics based on smartphones that can enable timely and personalized interventions. Examples are the PETAL patch sensor that applies multiple sensing mechanisms for wide-ranging views on wound status and closed-loop systems that connect biosensors to therapeutic devices to automate infection control. Additionally, self-powered biosensors that tap into body heat or energy from the biofluids themselves avoid any external batteries and are thus more effective in field use or with limited resources. Internet of Things connectivity allows further support for remote sharing and monitoring of data, thus supporting telemedicine applications. Although wearable biosensors have developed relatively rapidly and their prospects continue to expand, regular clinical application is stalled by significant challenges such as regulatory, cost, patient compliance, and technical problems related to sensor accuracy, biofouling, and power, among others, that need to be addressed by innovative solutions. The goal of this review is to synthesize current trends, challenges, and future directions in wound healing and infection monitoring, with emphasis on the potential for wearable biosensors to improve patient outcomes and reduce healthcare burdens. These innovations are leading the way toward next-generation wound care by bridging advanced materials science, biotechnology, and digital health.

Metabolomic profiling of plasma from glioma and meningioma patients based on two complementary mass spectrometry techniques

INTRODUCTION

Extracranial and intracranial tumors are a diverse group of malignant and benign neoplasms, influenced by multiple factors. Given the complex nature of these tumors and usually late or accidental diagnosis, minimally invasive, rapid, early, and accurate diagnostic methods are urgently required. Metabolomics offers promising insights into central nervous system tumors by uncovering distinctive metabolic changes linked to tumor development.

OBJECTIVES

This study aimed to elucidate the role of altered metabolites and the associated biological pathways implicated in the development of gliomas and meningiomas.

METHODS

The study was conducted on 95 patients with gliomas, 68 patients with meningiomas, and 71 subjects as a control group. The metabolic profiling of gliomas and meningiomas achieved by integrating untargeted metabolomic analysis based on GC-MS and targeted analysis performed using LC-MS/MS represents the first comprehensive study. Three comparisons (gliomas or meningiomas vs. controls as well as gliomas vs. meningiomas) were performed to reveal statistically significant metabolites.

RESULTS

Comparative analysis revealed 97, 56, and 27 significant metabolites for gliomas vs. controls, meningiomas vs. controls and gliomas vs. meningiomas comparison, respectively. Moreover, among above mentioned comparisons unique metabolites involved in arginine biosynthesis and metabolism, the Krebs cycle, and lysine degradation pathways were found. Notably, 2-aminoadipic acid has been identified as a metabolite that can be used in distinguishing two tumor types.

CONCLUSIONS

Our results provide a deeper understanding of the metabolic changes associated with brain tumor development and progression.

Multilevel plasticity and altered glycosylation drive aggressiveness in hypoxic and glucose-deprived bladder cancer cells

Bladder tumors with aggressive characteristics often present microenvironmental niches marked by low oxygen levels (hypoxia) and limited glucose supply due to inadequate vascularization. The molecular mechanisms facilitating cellular adaptation to these stimuli remain largely elusive. Employing a multi-omics approach, we discovered that hypoxic and glucose-deprived cancer cells enter a quiescent state supported by mitophagy, fatty acid β-oxidation, and amino acid catabolism, concurrently enhancing their invasive capabilities. Reoxygenation and glucose restoration efficiently reversed cell quiescence without affecting cellular viability, highlighting significant molecular plasticity in adapting to microenvironmental challenges. Furthermore, cancer cells exhibited substantial perturbation of protein O-glycosylation, leading to simplified glycophenotypes with shorter glycosidic chains. Exploiting glycoengineered cell models, we established that immature glycosylation contributes to reduced cell proliferation and increased invasion. Our findings collectively indicate that hypoxia and glucose deprivation trigger cancer aggressiveness, reflecting an adaptive escape mechanism underpinned by altered metabolism and protein glycosylation, providing grounds for clinical intervention.

Probing the Limits of Reactant Concentration and Volume in Primitive Polyphenyllactate Synthesis and Microdroplet Assembly Processes

Polyester microdroplets have been investigated as primitive protocell models that can exhibit relevant primitive functions such as biomolecule segregation, coalescence, and salt uptake. Such microdroplets assemble after dehydration synthesis of alpha-hydroxy acid (αHA) monomers, commonly available on early Earth, via heating at mild temperatures, followed by rehydration in aqueous media. αHAs, in particular, are also ubiquitous in biology, participating in a variety of biochemical processes such as metabolism, suggesting the possible strong link between primitive and modern αHA-based processes. Although some primitive αHA polymerization conditions have been probed previously, including monomer chirality and reaction temperature, relevant factors pertaining to early Earth's local environmental conditions that would likely affect primitive αHA polymerization are yet to be fully investigated. Hence, probing the entire breadth of possible conditions that could promote primitive αHA polymerization is required to understand the plausibility of polyester microdroplet assembly on early Earth at the origin of life. In particular, there are numerous aqueous environments available on early Earth that could have resulted in varying volumes and concentrations of αHA accumulation, which would have affected subsequent αHA polymerization reactions. Similarly, there were likely varying levels of salt in the various aqueous prebiotic solutions, such as in the ocean, lakes, and small pools, that may have affected primitive reactions. Here, we probe the limits of the dehydration synthesis and subsequent membraneless microdroplet (MMD) assembly of phenyllactic acid (PA), a well-studied αHA relevant to both biology and prebiotic chemistry, with respect to reactant concentration and volume and salinity through mass spectrometry- and microscopy-based observations. Our study showed that polymerization and subsequent microdroplet assembly of PA appear robust even at low reactant concentrations, smaller volumes, and higher salinities than those previously tested. This indicates that PA-polyester and its microdroplets are very much viable under a wide variety of conditions, thus more likely participating in prebiotic chemistries at the origins of life.

Lactate in skin homeostasis: metabolism, skin barrier, and immunomodulation

Lactate, once considered merely a byproduct of glycolysis, is now increasingly recognized as a multifunctional signaling molecule with roles beyond energy metabolism. It functions as an enzyme cofactor and binds to specific receptors to modulate cellular functions. In the skin, lactate is produced by various cell types. It is then transferred between cells or to the extracellular space, helping to balance cellular pH and to provide signals that regulate skin barrier and skin immunity. Additionally, lactate/lactate-related genes hold promising therapeutic potential for the treatment of skin tumors, inflammatory skin diseases, hair loss, and in cosmetic dermatology. This article highlights the latest advances in our understanding of lactate's biological effects on the skin and explores its therapeutic potential, offering insights into future research directions.

Glibenclamide targets MDH2 to relieve aging phenotypes through metabolism-regulated epigenetic modification

Mitochondrial metabolism-regulated epigenetic modification is a driving force of aging and a promising target for therapeutic intervention. Mitochondrial malate dehydrogenase (MDH2), an enzyme in the TCA cycle, was identified as an anti-aging target through activity-based protein profiling in present study. The expression level of MDH2 was positively correlated with the cellular senescence in Mdh2 knockdown or overexpression fibroblasts. Glibenclamide (Gli), a classic anti-glycemic drug, was found to inhibit the activity of MDH2 and relieve fibroblast senescence in an MDH2-dependent manner. The anti-aging effects of Gli were also further validated in vivo, as it extended the lifespan and reduced the frailty index of naturally aged mice. Liver specific Mdh2 knockdown eliminated Gli's beneficial effects in naturally aged mice, reducing p16INK4a expression and hepatic fibrosis. Mechanistically, MDH2 inhibition or knockdown disrupted central carbon metabolism, then enhanced the methionine cycle flux, and subsequently promoted histone methylation. Notably, the tri-methylation of H3K27, identified as a crucial methylation site in reversing cellular senescence, was significantly elevated in hepatic tissues of naturally aged mice with Mdh2 knockdown. Taken together, these findings reveal that MDH2 inhibition or knockdown delays the aging process through metabolic-epigenetic regulation. Our research not only identified MDH2 as a potential therapeutic target and Gli as a lead compound for anti-aging drug development, but also shed light on the intricate interplay of metabolism and epigenetic modifications in aging.

Glucose metabolism and endometrium decidualization

Prior to embryo implantation, the endometrial stromal cells (ESCs) during the menstrual cycle undergo a significant structural and functional transformation known as decidualization to support conception. During this process, glucose consumption and utilization by endometrial cells increase to meet energy demands. Abnormal glucose metabolism in the endometrium impairs decidualization, leading to pregnancy complications, including implantation failure and pregnancy loss. However, the mechanisms modulating glucose metabolism in endometrial stromal cells during decidualization are still unclear. In this review, we describe the functions and regulation of glucose transporters (GLUTs) involved in glucose uptake, as well as the modulation of key enzymes catalyzing glucose utilization. Moreover, we present recent findings on the role of glucose related metabolites in the decidualization of ESCs.

Regulatory role and therapeutic prospect of lactate modification in cancer

Post-translational modifications (PTMs) of proteins refer to the process of adding chemical groups, sugars, or other molecules to specific residues of target proteins following their biosynthesis by ribosomes. PTMs play a crucial role in processes such as signal transduction, epigenetics, and disease development. Lactylation is a newly discovered PTM that, due to its close association with lactate-the end product of glycolytic metabolism-provides a new perspective on the connection between cellular metabolic reprogramming and epigenetic regulation. Studies have demonstrated that lactylation plays a significant role in tumor progression and is associated with poor clinical prognosis. Abnormal histone lactylation can influence gene expression in both tumor cells and immune cells, thereby regulating tumor progression and immunosuppression. Lactylation of non-histone proteins can also modulate processes such as tumor proliferation and drug resistance. This review summarizes the latest research progress in the field of lactylation, highlighting its roles and mechanisms in tumorigenesis, tumor development, the tumor microenvironment, and immunosuppression. It also explores the potential application value of lactylation in tumor-targeted therapy and combined immunotherapy.

H4K12 lactylation potentiates mitochondrial oxidative stress via the Foxo1 pathway in diabetes-induced cognitive impairment

AIMS

To investigate the role and potential mechanisms of H4K12 lactylation modifications in diabetes-related cognitive impairment (DACD).

METHODS

Behavioral tests, HE staining, and immunohistochemistry were employed to assess cognitive function and the extent of brain tissue injury. Metabolomics and proteomics were applied to profile the metabolic regulatory network. We measured lactic acid and Pan-Kla levels in the brains of T2DM mice and high glucose-treated microglia. CUT&Tag technology was utilized to identify genes regulated by H4K12la. Small interfering RNA (siRNA) sequences and adeno-associated viruses (AAVs) were used to knock down key components in signaling pathways, evaluating the impact of histone lactylation on microglial polarization.

RESULTS

Lactic acid levels were significantly higher in the brains of T2DM mice and high glucose-treated microglia compared to controls, leading to an increase in pan histone lysine lactylation (Kla). We found that lactate directly induced an increase in H4K12la. CUT&Tag analysis revealed that elevated H4K12la activates the FOXO1/PGC-1α signaling pathway by enhancing binding to the FOXO1 promoter, promoting mitochondrial oxidative stress.

CONCLUSION

This study demonstrated that elevated H4K12la directly activates the FOXO1 signaling pathway, promoting oxidative stress and contributing to DACD phenotypes.

Functional mechanisms and potential therapeutic strategies for lactylation in liver diseases

Lactylation, a novel form of lactate-mediated protein post-translational modification (PTM), has been identified as a crucial regulator of gene expression and protein function through the modification of both histone and non-histone proteins. Liver disease is frequently characterized by a reprogramming of glucose metabolism and subsequent lactate accumulation. Recent research has implicated lactylation in a diverse array of hepatic pathologies, including liver injury, non-alcoholic fatty liver disease, liver fibrosis, and hepatocellular carcinoma. Consequently, lactylation has emerged as a pivotal regulatory mechanism in liver disease pathogenesis. This review aims to elucidate the intricate regulatory and functional mechanisms underlying lactylation, synthesize recent advancements in its role in various liver diseases, and highlight its potential as a therapeutic target for future interventions in hepatic disorders.

Heart Transplantation and Donation After Circulatory Death in Children. A Review of the Technological, Logistical and Ethical Framework

Heart transplant for adults following Donation after Circulatory Death (DCD) is well established in many parts of the world, including the United Kingdom (UK). Small child DCD hearts have now been recovered in the UK and internationally utilising novel technologies. Despite these recent advances, extension of this practice to pediatric cardiac transplantation has been slow and difficult despite the severe shortage of donors for children leading to a high number of deaths annually of children waiting for heart transplant. This is in direct contrast with the thriving UK programme of adult DCD heart transplant and pediatric DCD donation for non-cardiac organs. There has been insufficient action in addressing this inequality thus far. Barriers to development of a pediatric cardiac DCD programme are multifaceted: ethical concerns, technological paucity, financial and logistical hurdles. We describe the background, live issues, current developments and how we are driving resources toward a sustainable DCD programme for small children in the UK to provide valuable insights to other countries of the elements and principles at play. This is a call to responsible bodies to take urgent and achievable actions to establish an equitable paediatric DCD cardiac programme for donors, recipients and their families.

High-ammonia microenvironment promotes stemness and metastatic potential in hepatocellular carcinoma through metabolic reprogramming

BACKGROUND

Hepatocellular carcinoma (HCC) is a prevalent and aggressive form of liver cancer, characterized by frequent recurrence and metastasis, which remain significant obstacles to effective treatment. Ammonia accumulates in the tumor microenvironment of HCC due to dysfunction in the urea cycle, but the detailed impact of ammonia on HCC cells remains insufficiently understood.

METHODS

We exposed HCC cell lines to high concentrations of ammonium chloride to evaluate alterations in proliferation, stemness, and migratory potential. After ammonia removal, changes in cellular behavior were assessed using colony formation, and spheroid assays. Transcriptomic and metabolomic analyses were conducted to investigate ammonia-induced metabolic reprogramming and alterations in gene expression. Additionally, animal models were employed to validate the impact of ammonia on tumor growth and metastasis.

RESULTS

Exposure to high-ammonia conditions transiently suppressed HCC cell proliferation without inducing apoptosis. However, following ammonia removal, cells demonstrated increased proliferation, enhanced spheroid formation, and elevated migratory capacity. Transcriptomic analysis revealed the upregulation of genes associated with cell adhesion, migration, and glycolysis. Concurrently, metabolomic profiling indicated increased lactate production, facilitating the aggressive behavior of HCC cells after ammonia withdrawal. Animal experiments confirmed that high-ammonia exposure accelerated tumor growth and metastasis.

CONCLUSION

Ammonia exerts a dual effect on HCC progression: it initially suppresses cell growth but later promotes stemness, proliferation, and metastasis through metabolic reprogramming. Targeting ammonia metabolism or glycolysis in the tumor microenvironment may represent a promising therapeutic strategy for mitigating HCC recurrence and metastasis. Future studies utilizing clinical samples are required to validate these findings and identify potential therapeutic strategies targeting ammonia metabolism.

Integrative Analysis of Metabolome and Proteome in the Cerebrospinal Fluid of Patients with Multiple System Atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative synucleinopathy. Differentiating MSA from other synucleinopathies, especially in the early stages, is challenging because of its overlapping symptoms with other forms of Parkinsonism. Thus, there is a pressing need to clarify the underlying biological mechanisms and identify specific biomarkers for MSA. The metabolic profile of cerebrospinal fluid (CSF) is known to be altered in MSA. To further investigate the biological mechanisms behind the metabolic changes, we created a network of altered CSF metabolites in patients with MSA and analysed these changes using bioinformatic software. Acknowledging the limitations of metabolomics, we incorporated proteomic data to improve the overall comprehensiveness of the study. Our in silico predictions showed elevated ROS, cytoplasmic inclusions, white matter demyelination, ataxia, and neurodegeneration, with ATP concentration, neurotransmitter release, and oligodendrocyte count predicted to be suppressed in MSA CSF samples. Machine learning and dimension reduction are important multi-omics approaches as they handle large amounts of data, identify patterns, and make predictions while reducing variance without information loss and generating easily visualised plots that help identify clusters, patterns, or outliers. Thus, integrated multiomics and machine learning approaches are essential for elucidating neurodegenerative mechanisms and identifying potential diagnostic biomarkers of MSA.

Lactate and lactylation in cancer

Accumulated evidence has implicated the diverse and substantial influence of lactate on cellular differentiation and fate regulation in physiological and pathological settings, particularly in intricate conditions such as cancer. Specifically, lactate has been demonstrated to be pivotal in molding the tumor microenvironment (TME) through its effects on different cell populations. Within tumor cells, lactate impacts cell signaling pathways, augments the lactate shuttle process, boosts resistance to oxidative stress, and contributes to lactylation. In various cellular populations, the interplay between lactate and immune cells governs processes such as cell differentiation, immune response, immune surveillance, and treatment effectiveness. Furthermore, communication between lactate and stromal/endothelial cells supports basal membrane (BM) remodeling, epithelial-mesenchymal transitions (EMT), metabolic reprogramming, angiogenesis, and drug resistance. Focusing on lactate production and transport, specifically through lactate dehydrogenase (LDH) and monocarboxylate transporters (MCT), has shown promise in the treatment of cancer. Inhibitors targeting LDH and MCT act as both tumor suppressors and enhancers of immunotherapy, leading to a synergistic therapeutic effect when combined with immunotherapy. The review underscores the importance of lactate in tumor progression and provides valuable perspectives on potential therapeutic approaches that target the vulnerability of lactate metabolism, highlighting the Heel of Achilles for cancer treatment.

CPT1A mediates succinylation of LDHA at K318 site promoteing metabolic reprogramming in NK/T-cell lymphoma nasal type

Carnitine palmitoyltransferase 1A (CPT1A), a succinylating enzyme, is highly expressed in various malignant tumors and promotes tumor progression. Succinylation is a posttranslational modification that has been reported in various diseases, but its role in NK/T-Cell lymphoma nasal type (ENKTL-NT) remains underexplored. In this study, bioinformatics analysis showed that glycolytic is a major metabolic pathway in ENKTL-NT as the expression of many glycolytic related kinases are increased. CPT1A probably mediates glycolytic process, as indicated by GO-enrichment analysis. Studies showed that CPT1A was upregulated in ENKTL-NT tissues, and that high CPT1A expression was associated with poor prognosis of ENKTL-NT. CPT1A promoted the proliferation, colony formation, invasion and glycolytic process of ENKTL-NT cells and suppresses apoptosis. Mechanistically, CPT1A promotes succinylation of LDHA at lysine 318 (K318), which increase the protein stability and the final protein level of LDHA. Both knockdown and mutation (K318R) of LDHA abolished the cancer-promoting effects of CPT1A in ENKTL-NT. In all, this study reveals the mechanism underlying the cancer-promoting effects of CPT1A via inducing LDHA succinylation and metabolic reprogramming in ENKTL-NT. These findings might provide potential targets for the diagnosis or therapy of ENKTL-NT.

Targeting platinum-resistant ovarian cancer by disrupting histone and RAD51 lactylation

Rationale: Ovarian cancer is a highly lethal gynecological malignancy with common platinum resistance. Lactylation is involved in multiple biological processes. Thus, we explored the role of histone and non-histone lactylation in platinum resistance, providing a potential therapeutic target to overcome platinum resistance in ovarian cancer. Methods: We utilized gene set enrichment analysis to investigate lactylation-related pathway alterations between platinum-resistant and platinum-sensitive patients from the TCGA cohort. Differential expression of H3K9la was demonstrated using Western blotting and immunohistochemistry. Progression-free and overall survival were determined using a log-rank test. Drug response to cisplatin was evaluated by CCK8, apoptosis flow cytometry, and clonogenic assays in vitro. ChIP-seq and ChIP-qPCR assays were performed to identify downstream targets of H3K9la, which was further confirmed by qRT-PCR. LC-MS/MS was conducted to identify specific lactylation sites for RAD51. Co-IP was used to reveal the interaction between GCN5 and H3K9la or RAD51la. Cell line-derived and patient-derived xenograft (PDX) models of ovarian cancer were constructed for the in vivo experiments. Results: Our study showed elevated histone lactylation, especially of H3K9la, in platinum-resistant ovarian cancer. Moreover, high H3K9la indicated platinum resistance and poor prognosis of ovarian cancer. Impairing H3K9la enhanced response to cisplatin. Mechanistically, H3K9la directly activated RAD51 and BRCA2 expression to facilitate homologous recombination (HR) repair. Furthermore, RAD51K73la enhanced HR repair and subsequently conferred cisplatin resistance. H3K9la and RAD51K73la shared the same upstream regulator, GCN5. Notably, a GCN5 inhibitor remarkably improved the tumor-killing ability of cisplatin in PDX models of ovarian cancer. Conclusions: Our study demonstrated the essential role of histone and RAD51 lactylation in HR repair and platinum resistance. It also identified a potential therapeutic strategy to overcome platinum resistance and improve prognosis in ovarian cancer.

Tumor secretome shapes the immune landscape during cancer progression

The focus of cancer immunotherapy has traditionally been on immune cells and tumor cells themselves, often overlooking the tumor secretome. This review provides a comprehensive overview of the intricate relationship between tumor cells and the immune response in cancer progression. It highlights the pivotal role of the tumor secretome - a diverse set of molecules secreted by tumor cells - in significantly influencing immune modulation, promoting immunosuppression, and facilitating tumor survival. In addition to elucidating these complex interactions, this review discusses current clinical trials targeting the tumor secretome and highlights their potential to advance personalized medicine strategies. These trials aim to overcome the challenges of the tumor microenvironment by designing therapies tailored to the secretome profiles of individual cancer patients. In addition, advances in proteomic techniques are highlighted as essential tools for unraveling the complexity of the tumor secretome, paving the way for improved cancer treatment outcomes.

Identification of a Lactate Accumulation Model to Explain the Heterogeneity in Prognosis, Immune Landscape, and Tumor Environment for HNSCC patients

Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent cancers with a high mortality rate. Lactate accumulation, a hallmark of cancer, has received extensive attention, but its role in HNSCC remains underexplored. Therefore, we identified 33 prognostic genes related to lactate accumulation. By consensus clustering, we separated all HNSCC samples into cluster_A or cluster_B and explored the difference of clinicopathological characteristics and genomics landscape. Next, we performed LASSO analysis and RSF to calculate the lactate-related gene score (LRGS) and constructed a risk model with high accuracy for predicting survival, as estimated by ROC, nomogram, and calibration curve. Then, through OncoPredict algorithm and TCIA, we filter the suitable drugs, especially immunology with diverse LRGS. GSEA analysis showed that the DEGs of LRGS were enriched in activation of immune response and positive regulation of immune response. Moreover, we developed a tumor-infiltrating immune-related lncRNA signature (TILSig) through a combination of 115 immune cell lines from 16 GEO datasets and DealGPL570. Subsequently, we identified the 9 tumor-infiltrating immune-related lncRNAs and calculated the TIL_score. The correlations among these tumor-infiltrating immune-related lncRNAs, hub lactate-related genes and LRGS levels were visualized. According to validation using multiple datasets including TCGA, GSE65858, GSE41613, GSE27020, and the IMvigor 210 database, CARS2, NFU1, and SYNJ1 were identified as hub genes. In light of a comprehensive pan-cancer study, we analyzed these genes to detect the potential clinical value. In conclusion, the constructed LRGS provides important insights for subsequent mechanistic research and can guide clinicians in proposing therapeutic strategies for HNSCC patients.

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.

Metabolic crossroads: unravelling immune cell dynamics in gastrointestinal cancer drug resistance

Metabolic reprogramming within the tumor microenvironment (TME) plays a critical role in driving drug resistance in gastrointestinal cancers (GI), particularly through the pathways of fatty acid oxidation and glycolysis. Cancer cells often rewire their metabolism to sustain growth and reshape the TME, creating conditions such as nutrient depletion, hypoxia, and acidity that impair antitumor immune responses. Immune cells within the TME also undergo metabolic alterations, frequently adopting immunosuppressive phenotypes that promote tumor progression and reduce the efficacy of therapies. The competition for essential nutrients, particularly glucose, between cancer and immune cells compromises the antitumor functions of effector immune cells, such as T cells. Additionally, metabolic by-products like lactate and kynurenine further suppress immune activity and promote immunosuppressive populations, including regulatory T cells and M2 macrophages. Targeting metabolic pathways such as fatty acid oxidation and glycolysis presents new opportunities to overcome drug resistance and improve therapeutic outcomes in GI cancers. Modulating these key pathways has the potential to reinvigorate exhausted immune cells, shift immunosuppressive cells toward antitumor phenotypes, and enhance the effectiveness of immunotherapies and other treatments. Future strategies will require continued research into TME metabolism, the development of novel metabolic inhibitors, and clinical trials evaluating combination therapies. Identifying and validating metabolic biomarkers will also be crucial for patient stratification and treatment monitoring. Insights into metabolic reprogramming in GI cancers may have broader implications across multiple cancer types, offering new avenues for improving cancer treatment.

Varying Bifidobacterium species in the maternal-infant gut microbiota correlate with distinct early neurodevelopmental outcomes

The impact of mother-infant microbiota on neurodevelopment is an area of interest, but longitudinal studies are scarce. Using a cohort of 520 families from the Jiangsu birth cohort in China, we reveal that the maternal gut microbiota during early pregnancy play a substantial role, accounting for 3.34% of the variance in offspring neurodevelopmental scores. This contribution is notably higher than the 1.24% attributed to the infants' own microbiota at 1 year of age, underscoring the significant influence of maternal gut health on early child development. Remarkably, an elevation in maternal Bifidobacterium pseudocatenulatum is linked to decreased cognitive scores, whereas an enrichment of Bifidobacterium longum at 1 year of age is associated with higher cognitive scores. Furthermore, we find that maternal B. pseudocatenulatum is linked to the heterolactic fermentation metabolic pathway, while infant B. longum is associated with the Bifidobacterium shunt pathway. In summary, our analysis implies that maternal and infant gut microbiota play a distinct role in neurodevelopment, suggesting potential strategies for improving neurodevelopmental outcomes during early pregnancy or infant development by targeting gut microbiota composition.

Lactic acid inhibits the interaction between PD-L1 protein and PD-L1 antibody in the PD-1/PD-L1 blockade therapy-resistant tumor

Immune checkpoint blockade therapy targeting the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis has shown remarkable clinical impact in multiple cancer types. Nonetheless, despite the recent success of PD-1/PD-L1 blockade therapy, such response rates in cancer patients have been limited to tumors encompassing specific tumor microenvironment characteristics. The altered metabolic activity of cancer cells shapes the anti-tumor immune response by affecting the activity of immune cells. However, it remains mostly unknown how the altered metabolic activity of cancer cells impacts their resistance to PD-1/PD-L1 blockade therapy. Here, we found that tumor cell-derived lactic acid renders the immunosuppressive tumor microenvironment in the PD-1/PD-L1 blockade-resistant tumors by inhibiting the interaction between the PD-L1 protein and anti-PD-L1 antibody. Furthermore, we showed that the combination therapy of targeting PD-L1 with our PD-L1 antibody-drug conjugate (PD-L1-ADC) and reducing lactic acid with the monocarboxylate transporter 1 (MCT-1) inhibitor, AZD3965, can effectively treat the PD-1/PD-L1 blockade-resistant tumors. The findings of this study provide a new mechanism of how lactic acid induces an immunosuppressive tumor microenvironment and suggest a potential combination treatment to overcome the tumor resistance to PD-1/PD-L1 blockade therapy.

Integrative bioinformatics and experimental analyses identify U2SURP as a novel lactylation-related prognostic signature in esophageal carcinoma

The lactylation modification has been implicated in several cancer types; however, the role of lactylation modification-related genes in esophageal carcinoma (EC) remains underexplored. Utilizing a set of 16 lactylation modification-related genes, cohorts of patients with EC were stratified into two distinct clusters, characterized by significant disparities in both survival outcomes and the immune microenvironment. An extensive bioinformatics analysis unveiled 382 differentially expressed genes (DEGs) between these two clusters. A subsequent univariate Cox regression analysis identified 24 DEGs specifically associated with lactylation, forming the basis of a constructed lactylation-related score. The resultant lactylation-related score exhibited notable predictive efficacy for survival and other clinicopathological traits, which was validated through calibration curves, Kaplan-Meier survival curves and the Wilcoxon test. Moreover, the lactylation-related score displayed a close correlation with immune cell infiltration in EC. Notable differential expressions of immune checkpoints and regulators were observed between groups stratified by low and high lactylation scores, with the latter exhibiting a more favorable response to anti-PD-1/PD-L1 therapy. Furthermore, the expression profile of U2 snRNP associated SURP domain containing (U2SURP), a constituent of the lactylation-related score, underwent both ex vivo and in vitro validation. The expression of U2SURP was significantly associated with lactylation levels, histological grade and tumor stage. Notably, knockdown of U2SURP expression inhibited the lactylation levels, immune genes IL-1A and IL-1B, proliferation, migration and invasion of EC cells. In conclusion, the lactylation-related score developed in the present study showed promise in predicting the prognosis and immunotherapeutic responses among patients with EC. Moreover, the identification of U2SUPR as a novel oncogene in EC suggests its potential as a prospective therapeutic target for EC treatment.

Lactylation and human disease

BACKGROUND

Lactylation, a new epigenetic modification, is an important way in which lactate exerts physiological functions. There is a close relationship between increased lactylations caused by lactate and glycolysis, which can interact and play a role in disease through lactate as an intermediate mediator. Current research on lactylations has focused on histone lactylation, but non-histone lactylation also has greater research potential. Due to the ubiquity of lactate modifications in mammalian cells, an increasing number of studies have found that lactate modifications play important roles in tumour cell metabolism, gene transcription and immunity.

METHODS

A systematic literature search was carried out using search key terms and synonyms. Full-paper screening was performed based on specific inclusion and exclusion criteria.

RESULTS

Many literatures have reported that the lactylation of protein plays an important role in human diseases and is involved in the occurrence and development of human diseases.

CONCLUSIONS

This article summary the correlation between lactylation and glycolysis, histones and non-histone proteins; the relationship between lactonation modifications and tumour development; and the current existence of lactylation-related inhibitors, with a view to provide new basic research ideas and clinical therapeutic tools for lactylation-related diseases.

D-sodium lactate promotes the activation of NF-κB signaling pathway induced by lipopolysaccharide via histone lactylation in bovine mammary epithelial cells

Lactate is a glycolytic end product that is further metabolized as an energy source. This end product has been associated with certain diseases, including sepsis and tumors, and it can regulate the transition of macrophages to an anti-inflammatory state. This study aimed to explore the effects of lactate on the inflammatory responses of mammary gland epithelial cells, which constitute the first line of defense against pathogens in mammary glands. Bovine mammary epithelial cells (BMECs) were challenged with lipopolysaccharide (LPS) in the presence or absence of D-sodium lactate (D-nala). LPS exposure increased the concentration of lactate both inside and outside the cells. Further, inhibiting glycolysis diminished the LPS-induced production of proinflammatory cytokines. Treatment with LPS, exogenous D-nala, and their combination upregulated the expression levels of MCT1, increased the intracellular levels of lactate and histone H3 lysine 18 lactylation (H3K18la), and activated the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathway. The lactylation of H3K18 was mediated by p300/CBP. The p300/CBP inhibitor C646 decreased the level of H3K18la, reversing the activation of the NF-κB signaling pathway and release of proinflammatory cytokines. Therefore, LPS increased the intracellular level of lactate by upregulating MCT1 and glycolysis. D-nala exacerbated the LPS-induced inflammatory responses in BMECs. Moreover, intracellular lactate enhanced the activation of the NF-κB signaling pathway through the p300/CBP-mediated lactylation of H3K18. Thus, the findings of this study expand our understanding of lactate function in immune regulation.

NSUN2 lactylation drives cancer cell resistance to ferroptosis through enhancing GCLC-dependent glutathione synthesis

Lactate-mediated lactylation on target proteins is recently identified as the novel posttranslational modification with profound biological functions. RNA 5-methylcytosine (m5C) modification possesses dynamic and reversible nature, suggesting that activity of its methyltransferase NSUN2 is actively regulated. However, how NSUN2 activity is response to acidic condition in tumor microenvironment and then regulates cancer cell survival remain to be clarified. Here, we demonstrate that NSUN2 activity is enhanced by lactate-mediated lactylation at lysine 508, which then targets glutamate-cysteine ligase catalytic subunit (GCLC) mRNA to facilitates GCLC m5C formation and mRNA stabilization. The activated GCLC induces higher level of intracellular GSH accompanied by decreased lipid peroxidation and resistant phenotype to ferroptosis induction by doxorubicin (Dox) in gastric cancer cells. Specifically, the effect of NSUN2 lactylation-GCLC-GSH pathway is nearly lost when NSUN2 K508R or GCLC C-A mutant (five cytosine sites) was introduced into the cancer cells. We further identify the catalytic subunit N-α-acetyltransferase 10 (NAA10) as the lactytransferase of NSUN2, and lactate treatment substantially enhances their association and consequent NSUN2 activation. Taken together, our findings convincingly elucidate the signaling axis of NAA10-NSUN2-GCLC that potently antagonizes the ferroptosis under acidic condition, and therefore, targeting NSUN2 lactylation might be an effective strategy in improving the prognosis of cancer patients.

Uncovering the protective role of lipid droplet accumulation against acid-induced oxidative stress and cell death in osteosarcoma

Extracellular acidosis stemming from altered tumor metabolism promotes cancer progression by enabling tumor cell adaptation to the hostile microenvironment. In osteosarcoma, we have previously shown that acidosis increases tumor cell survival alongside substantial lipid droplet accumulation. In this study, we explored the role of lipid droplet formation in mitigating cellular stress induced by extracellular acidosis in osteosarcoma cells, thereby enhancing tumor survival during progression. Specifically, we examined how lipid droplets shield against reactive oxygen species induced by extracellular acidosis. We demonstrated that lipid droplet biogenesis is critical for acid-exposed tumor cell survival, as it starts shortly after acid exposure (24 h) and inversely correlates with ROS levels (DCFH-DA assay), lipid peroxidation (Bodipy assay), and the antioxidant response, as also revealed by NRF2 transcript. Additionally, extracellular metabolites, such as lactate, and interaction with mesenchymal stromal cells within the tumor microenvironment intensify lipid droplet build-up in osteosarcoma cells. Critically, upon targeting two key proteins implicated in LD formation - PLIN2 and DGAT1 - cell viability significantly declined while ROS production escalated. In summary, our findings underscore the vital reliance of acid-exposed tumor cells on lipid droplet formation to scavenge oxidative stress. We conclude that the rewiring of lipid metabolism driven by microenvironmental cues is of paramount importance for the survival of metabolically altered osteosarcoma cells in acidic condition. Overall, we suggest that targeting key members of lipid droplet biogenesis may eradicate more aggressive and resistant tumor cells, uncovering potential new treatment strategies for osteosarcoma.

CNDP2: An Enzyme Linking Metabolism and Cardiovascular Diseases?

The heart requires a substantial amount of energy to function, utilising various substrates including lipids, glucose and lactate as energy sources. In times of increased stress, lactate becomes the primary energy source of the heart, but persistently elevated lactate levels are linked to poor patient outcomes and increased mortality. Recently, carnosine dipeptidase II (CNDP2) was discovered to catalyse the formation of Lac-Phe, an exercise-induced metabolite derived from lactate, which has been shown to suppress appetite in mice and reduce adipose tissue in humans. This review discusses CNDP2, including its role in lactate clearance, carnosine hydrolysis, oxidative stress regulation, and involvement in metabolite regulation. The association between CNDP2 and cardiometabolic and renal diseases is also explored, and knowledge gaps are highlighted. CNDP2 appears to be a complex participant in human physiological processes and disease, necessitating additional research to unveil its functions and potential therapeutic applications.

Endothelial monocarboxylate transporter 1 drives atherosclerosis via a lactate/NADH/CtBP-mediated transrepression pathway

The accumulation of lactate in tissue microenvironments is associated with atherosclerosis, but its precise role in atherogenesis remains largely unknown. This study demonstrated that lactate accumulation in aortic tissues and blood is correlated with increased monocarboxylate transporter 1 (Mct1) expression in endothelial cells (ECs) within atherosclerotic plaques. Lactate uptake via Mct1 triggers an inflammatory response in ECs. The administration of endothelial-targeting nanoparticles containing siRNA against Mct1 reduces endothelial inflammation and atherogenesis in Apoe-/- mice. Mechanistic studies revealed that the conversion of lactate to pyruvate, along with NADH production and oligomerization of the NADH-sensitive transcriptional corepressor C-terminal binding protein 1 (CtBP1), is necessary for the proinflammatory effects of lactate. Monomeric CtBP1 interacts with the transcriptional repressor forkhead box P1 (FOXP1) to suppress endothelial adhesion molecule expression. However, NADH-induced oligomerization of CtBP1 prevents its binding to FOXP1, significantly reducing FOXP1-mediated transrepression of endothelial adhesion molecules. Moreover, silencing Foxp1 in ECs negates the atheroprotective effect of endothelial Mct1 knockdown in Apoe-/- mice. These findings suggest that lactate/MCT1-induced epigenetic reprogramming represents a potential therapeutic target in atherosclerosis.