Hexokinase 2-mediated gene expression via histone lactylation is required for hepatic stellate cell activation and liver fibrosis

Hepatic stellate cells promote hepatocellular carcinoma development by regulating histone lactylation: Novel insights from single-cell RNA sequencing and spatial transcriptomics analyses

This study evaluated the cellular heterogeneity and molecular mechanisms of hepatocellular carcinoma (HCC). Single cell RNA sequencing (scRNA-seq), transcriptomic data, histone lactylation-related genes were collected from public databases. Cell-cell interaction, trajectory, pathway, and spatial transcriptome analyses were executed. Differential expression and survival analyses were conducted. Western blot, Real-time reverse transcription PCR (qRT-PCR), and Cell Counting Kit 8 (CCK8) assay were used to detect the expression of αSMA, AKR1B10 and its target genes, and verify the roles of AKR1B10 in HCC cells. Hepatic stellate cell (HSC) subgroups strongly interacted with tumor cell subgroups, and their spatial distribution was heterogeneous. Two candidate prognostic genes (AKR1B10 and RMRP) were obtained. LONP1, NPIPB3, and ZSWIM6 were determined as AKR1B10 targets. Besides, the expression levels of AKR1B10 and αSMA were significantly increased in LX-2 + HepG2 and LX-2 + HuH7 groups compared to those in LX-2 group, respectively. sh-AKR1B10 significantly inhibited the HCC cell proliferation and change the expression of AKR1B10 target genes, Bcl-2, Bax, Pan Kla, and H3K18la at protein levels. Our findings unveil the pivotal role of HSCs in HCC pathogenesis through regulating histone lactylation.

Histone H4K12 lactylation promotes malignancy progression in triple-negative breast cancer through SLFN5 downregulation

Lactylation, a newly identified post-translational modification, is uncertain in its implication in triple-negative breast cancer (TNBC). In this study, we analyzed 60 TNBC samples using immunohistochemical staining and revealed elevated levels of pan-lactylated proteins and specific histone H4K12 lactylation in tumor tissues, correlating with TNBC progression. Lactate exposure in TNBC cell lines significantly induced lysine lactylation at the H4K12 site, leading to alterations in gene profiles and reduced apoptosis. These effects were attenuated by DCA or sodium Oxamate, inhibitors of endogenous lactate production. Gene sequencing showed an increase in Schlafen 5 (SLFN5) expression in TNBC cells treated with Oxamate, contrasting with the effects of lactate exposure. Analysis of TNBC tissues showed a negative correlation between H4K12 lactylation and SLFN5 protein levels. Overexpression of SLFN5 countered the effects of lactate on apoptosis and tumor growth, highlighting its pivotal role in TNBC malignancy. CUT&Tag sequencing indicated that lactylated H4K12 potentially binds to the SLFN5 promoter region. Luciferase reporter assays further verified that lactate-induced suppression of SLFN5 promoter activity is mediated by wild-type H4K12, but not by its R or A mutants, verified by both in vitro and in vivo apoptosis detection in response to lactate and Oxamate stimulation. These results establish that H4K12 lactylation, induced by lactate in TNBC cells, specifically suppresses SLFN5 expression, contributing to TNBC malignancy. Our findings illuminate a critical histone lactylation-dependent carcinogenic pathway in TNBC.

Reliability of Serum-Derived Connectome Indicators in Identifying Cirrhosis

Patients with cirrhosis face a heightened risk of complications, underscoring the importance of identification. We have developed a Connectome strategy that combines metabolites with peptide spectral matching (PSM) in proteomics to integrate metabolomics and proteomics, identifying specific metabolites bound to blood proteins in cirrhosis using open search proteomics methods. Analysis methods including Partial Least Squares Discriminant Analysis (PLS-DA), Uniform Manifold Approximation and Projection (UMAP), and hierarchical clustering were used to distinguish significant differences among the Cirrhosis group, Chronic Hepatitis B (CHB) group, and Healthy group. In this study, we identified 81 cirrhosis-associated connectomes and established an effective model distinctly distinguishing cirrhosis from chronic hepatitis B and healthy samples, confirmed by PLS-DA, hierarchical clustering analysis, and UMAP analysis, and further validated using six new cirrhosis samples. We established a Unified Indicator for Identifying cirrhosis, including tyrosine, Unnamed_189.2, thiazolidine, etc., which not only enables accurate identification of cirrhosis groups but was also further validated using six new cirrhosis samples and extensively supported by other cirrhosis research data (PXD035024). Our study reveals that characteristic cirrhosis connectomes can reliably distinguish cirrhosis from CHB and healthy groups. The established unified cirrhotic indicator facilitates the identification of cirrhosis cases in both this study and additional research data.

The role of forkhead box M1-methionine adenosyltransferase 2 A/2B axis in liver inflammation and fibrosis

Methionine adenosyltransferase 2 A (MAT2A) and MAT2B are essential for hepatic stellate cells (HSCs) activation. Forkhead box M1 (FOXM1) transgenic mice develop liver inflammation and fibrosis. Here we examine if they crosstalk in male mice. We found FOXM1/MAT2A/2B are upregulated after bile duct ligation (BDL) and carbon tetrachloride (CCl4) treatment in hepatocytes, HSCs and Kupffer cells (KCs). FDI-6, a FOXM1 inhibitor, attenuates the development and reverses the progression of CCl4-induced fibrosis while lowering the expression of FOXM1/MAT2A/2B, which exert reciprocal positive regulation on each other transcriptionally. Knocking down any of them lowers HSCs and KCs activation. Deletion of FOXM1 in hepatocytes, HSCs, and KCs protects from BDL-mediated inflammation and fibrosis comparably. Interestingly, HSCs from Foxm1Hep-/-, hepatocytes from Foxm1HSC-/-, and HSCs and hepatocytes from Foxm1KC-/- have lower FOXM1/MAT2A/2B after BDL. This may be partly due to transfer of extracellular vesicles between different cell types. Altogether, FOXM1/MAT2A/MAT2B axis drives liver inflammation and fibrosis.

Dynamic changes of protein lactylation and their correlations with the glycolytic process during the postmortem acidification of broiler breast

This experiment aimed to reveal the dynamic changes of protein post-translational lactylation modifications and their correlations with the glycolytic process in broiler breast muscle within 48 h of postmortem acidification. The experiment involved 12 male AA broilers, 42 days old, with similar body weights (2.8 ± 0.05 kg). The breast fillets (Pectoralis major) were collected after slaughter, and samples were taken at various time points: 0, 15 min, 30 min, 45 min, 60 min, 2 h, 4 h, 6 h, 8 h, 12 h, 18 h, 24 h, 36 h, and 48 h postmortem. The results showed that the rate of glycogen decline in the muscle was highest at 45 min postmortem, and glycogen levels tended to stabilize at 8 h postmortem. The lactate content in the breast reached its highest level at 4 h postmortem and began to decrease, stabilizing at 24 h postmortem. Additionally, the glycolytic potential increased gradually in the first 4 h postmortem, decreased rapidly from 4 to 8 h. Similarly, lactylation modification levels were highest at 8 h postmortem, but stabilized at 12 h postmortem. During this process, the protein expression of the enzymatic lactylation modifier p300 showed no significant difference, while the content of the nonenzymatic lactylation substrate lactoylglutathione significantly decreased at 8 h and 24 h postmortem. Correlation analysis found that lactylation levels were negatively correlated with glycogen content, glucose content, glycolytic potential, and pH value, while positively correlated with lactate content. Besides, there was a positive correlation between lactylation levels and the protein expression of hexokinase, phosphoglycerate kinase 2, phosphoglucomutase 1, and triosephosphate isomerase. Additionally, lactylation levels were positively correlated with the activities of lactate dehydrogenase and phosphofructokinase. In summary, our experiment elucidated the dynamic changes in the entire glycolytic pathway in broiler pectoral muscle during acidification. During this process, lactylation modifications may participate in the glycolysis process by regulating the protein expression and activity of glycolytic enzymes.

Lactylation: A Novel Post-Translational Modification with Clinical Implications in CNS Diseases

Lactate, an important metabolic product, provides energy to neural cells during energy depletion or high demand and acts as a signaling molecule in the central nervous system. Recent studies revealed that lactate-mediated protein lactylation regulates gene transcription and influences cell fate, metabolic processes, inflammation, and immune responses. This review comprehensively examines the regulatory roles and mechanisms of lactylation in neurodevelopment, neuropsychiatric disorders, brain tumors, and cerebrovascular diseases. This analysis indicates that lactylation has multifaceted effects on central nervous system function and pathology, particularly in hypoxia-induced brain damage. Highlighting its potential as a novel therapeutic target, lactylation may play a significant role in treating neurological diseases. By summarizing current findings, this review aims to provide insights and guide future research and clinical strategies for central nervous system disorders.

Crossing epigenetic frontiers: the intersection of novel histone modifications and diseases

Histone post-translational modifications (HPTMs), as one of the core mechanisms of epigenetic regulation, are garnering increasing attention due to their close association with the onset and progression of diseases and their potential as targeted therapeutic agents. Advances in high-throughput molecular tools and the abundance of bioinformatics data have led to the discovery of novel HPTMs which similarly affect gene expression, metabolism, and chromatin structure. Furthermore, a growing body of research has demonstrated that novel histone modifications also play crucial roles in the development and progression of various diseases, including various cancers, cardiovascular diseases, infectious diseases, psychiatric disorders, and reproductive system diseases. This review defines nine novel histone modifications: lactylation, citrullination, crotonylation, succinylation, SUMOylation, propionylation, butyrylation, 2-hydroxyisobutyrylation, and 2-hydroxybutyrylation. It comprehensively introduces the modification processes of these nine novel HPTMs, their roles in transcription, replication, DNA repair and recombination, metabolism, and chromatin structure, as well as their involvement in promoting the occurrence and development of various diseases and their clinical applications as therapeutic targets and potential biomarkers. Moreover, this review provides a detailed overview of novel HPTM inhibitors targeting various targets and their emerging strategies in the treatment of multiple diseases while offering insights into their future development prospects and challenges. Additionally, we briefly introduce novel epigenetic research techniques and their applications in the field of novel HPTM research.

A New Target for Hepatic Fibrosis Prevention and Treatment: The Warburg Effect

Hepatic fibrosis is a major public health problem that endangers human wellbeing. In recent years, a number of studies have revealed the important impact of metabolic reprogramming on the occurrence and development of hepatic fibrosis. Among them, the Warburg effect, as an intracellular glucose metabolism reprogramming, can promote the occurrence and development of hepatic fibrosis by promoting the activation of hepatic stellate cells (HSCs) and inducing the polarization of liver macrophages (KC). Understanding the Warburg effect and its important role in the progression of hepatic fibrosis will assist in developing new strategies for the prevention and treatment of hepatic fibrosis. This review focuses on the Warburg effect and the specific mechanism by which it affects the progression of hepatic fibrosis by regulating HSCs activation and KC polarization. In addition, we also summarize and discuss the related experimental drugs and their mechanisms that inhibit the Warburg effect by targeting key proteins of glycolysis in order to improve hepatic fibrosis in the hope of providing more effective strategies for the clinical treatment of hepatic fibrosis.

BRD3308 suppresses macrophage oxidative stress and pyroptosis via upregulating acetylation of H3K27 in sepsis-induced acute lung injury

Background

Sepsis-induced acute lung injury (ALI) leads to severe hypoxemia and respiratory failure, contributing to poor prognosis in septic patients. Endotoxin dissemination triggers oxidative stress and the release of inflammatory cytokines in macrophages, initiating diffuse alveolar damage. The role of epigenetic histone modifications in organ injury is increasingly recognized. The present study aimed to investigate the use of a histone modification inhibitor to alleviate sepsis-induced ALI, revealing a new strategy for improving sepsis patient survival.

Methods

In vivo models of ALI were established through the intraperitoneal injection of lipopolysaccharide and cecal ligation and puncture surgery. Furthermore, the disease process was simulated in vitro by stimulating Tamm-Horsfall protein-1 (THP-1) cells with lipopolysaccharide. Hematoxylin and eosin staining, blood gas analysis and pulmonary function tests were utilized to assess the extent of lung tissue damage. Western blot analysis, real-time polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescence were used to measure the levels and distribution of the indicated indicators within cells and tissues. Reactive oxygen species and autophagic flux alterations were detected using specific probes.

Results

BRD3308, which is a inhibitor of histone deacetylase 3, improved lung tissue damage, inflammatory infiltration and edema in ALI by inhibiting Nod-like receptor protein3-mediated pyroptosis in macrophages. By upregulating autophagy, BRD3308 improved the disruption of redox balance in macrophages and reduced the accumulation of reactive oxygen species. Mechanistically, BRD3308 inhibited histone deacetylase 3 activity by binding to it and altering its conformation. Following histone deacetylase 3 inhibition, acetylation of H3K27 was significantly increased. Moreover, the increase in H3K27Ac led to the upregulation of autophagy-related gene 5, a key component of autophagosomes, thereby activating autophagy.

Conclusions

BRD3308 inhibits oxidative stress and pyroptosis in macrophages by modulating histone acetylation, thereby preventing sepsis-induced ALI. The present study provides a potential strategy and theoretical basis for the clinical treatment of sepsis-induced ALI.

Lactate drives epithelial-mesenchymal transition in diabetic kidney disease via the H3K14la/KLF5 pathway

High levels of urinary lactate are an increased risk of progression in patients with diabetic kidney disease (DKD). However, it is still unveiled how lactate drive DKD. Epithelial-mesenchymal transition (EMT), which is characterized by the loss of epithelial cells polarity and cell-cell adhesion, and the acquisition of mesenchymal-like phenotypes, is widely recognized a critical contributor to DKD. Here, we found a switch from oxidative phosphorylation (OXPHOS) toward glycolysis in AGEs-induced renal tubular epithelial cells, thus leading to elevated levels of renal lactic acid. We demonstrated that reducing the lactate levels markedly delayed EMT progression and improved renal tubular fibrosis in DKD. Mechanically, we observed lactate increased the levels of histone H3 lysine 14 lactylation (H3K14la) in DKD. ChIP-seq & RNA-seq results showed histone lactylation contributed to EMT process by facilitating KLF5 expression. Moreover, KLF5 recognized the promotor of cdh1 and inhibited its transcription, which accelerated EMT of DKD. Additionally, nephro-specific knockdown and pharmacological inhibition of KLF5 diminished EMT development and attenuated DKD fibrosis. Thus, our study provides better understanding of epigenetic regulation of DKD pathogenesis, and new therapeutic strategy for DKD by disruption of the lactate-drived H3K14la/KLF5 pathway.

The influence of peritumoral parenchyma on local tumor progression of hepatocellular carcinoma after thermal ablation: a retrospective multicenter study

BACKGROUND

With the increasing importance of thermal ablation (TA) in hepatocellular carcinoma (HCC) treatment, local tumor progression (LTP) has become a nonignorable recurrence type after ablation.

PURPOSES

To analyze the influence of peritumoral liver parenchyma on LTP and to explore the possible reasons for this influence.

METHODS

Ablated HCCs with peritumoral parenchymal biopsy and ablation margins greater than 5 mm were included from two hospitals. The grade of necroinflammatory activity (G) and stage of fibrosis (S) of the parenchyma were evaluated by Scheuer staging system. Univariate/multivariate Cox model was used to analyze the possible factors influencing LTP. Peritumoral satellite focus rate, ablation energy, ablation volume after treatment, ablation volume after one-month, and volume reduction rate were collected and analyzed to explore the possible reasons for influence. Propensity score matching (PSM) was used to balance baselines across different groups.

RESULTS

346 HCCs (64 with LTP, 282 without LTP) were enrolled from January 2013 to June 2022, with a median follow-up of 27 months. Univariate/multivariate analysis showed fibrosis was a protective factor in LTP (OR = 0.70, 95%CI: 0.55-0.89). The low-fibrosis group exhibited higher satellite focus rate (15.6% vs. 8.4%, p = 0.048), lower ablation energy (22637 ± 9424 J vs. 33352 ± 13779 J, p < 0.001) and higher volume reduction rate (0.33 ± 0.06 vs. 0.25 ± 0.06, p < 0.001) than the high-fibrosis group. Therefore, we speculated that the protective effect of fibrosis was due to its blocking of tumor invasion and reduction of sublethal zones.

CONCLUSION

Fibrosis of the peritumoral liver parenchyma is a stable protective factor in LTP occurrence.

Lactylation signature identifies liver fibrosis phenotypes and traces fibrotic progression to hepatocellular carcinoma

Introduction

Precise staging and classification of liver fibrosis are crucial for the hierarchy management of patients. The roles of lactylation are newly found in the progression of liver fibrosis. This study is committed to investigating the signature genes with histone lactylation and their connection with immune infiltration among liver fibrosis with different phenotypes.

Methods

Firstly, a total of 629 upregulated and 261 downregulated genes were screened out of 3 datasets of patients with liver fibrosis from the GEO database and functional analysis confirmed that these differentially expressed genes (DEGs) participated profoundly in fibrosis-related processes. After intersecting with previously reported lactylation-related genes, 12 DEGs related to histone lactylation were found and narrowed down to 6 core genes using R algorithms, namely S100A6, HMGN4, IFI16, LDHB, S100A4, and VIM. The core DEGs were incorporated into the Least absolute shrinkage and selection operator (LASSO) model to test their power to distinguish the fibrotic stage.

Results

Advanced fibrosis presented a pattern of immune infiltration different from mild fibrosis, and the core DEGs were significantly correlated with immunocytes. Gene set and enrichment analysis (GSEA) results revealed that core DEGs were closely linked to immune response and chemokine signaling. Samples were classified into 3 clusters using the LASSO model, followed by gene set variation analysis (GSVA), which indicated that liver fibrosis can be divided into status featuring lipid metabolism reprogramming, immunity immersing, and intermediate of both. The regulatory networks of the core genes shared several transcription factors, and certain core DEGs also presented dysregulation in other liver fibrosis and idiopathic pulmonary fibrosis (IPF) cohorts, indicating that lactylation may exert comparable functions in various fibrotic pathology. Lastly, core DEGs also exhibited upregulation in HCC.

Discussion

Lactylation extensively participates in the pathological progression and immune infiltration of fibrosis. Lactylation and related immune infiltration could be a worthy focus for the investigation of HCC developed from liver fibrosis.

SIRT1 improves lactate homeostasis in the brain to alleviate parkinsonism via deacetylation and inhibition of PKM2

Sirtuin 1 (SIRT1) is a histone deacetylase and plays diverse functions in various physiological events, from development to lifespan regulation. Here, in Parkinson's disease (PD) model mice, we demonstrated that SIRT1 ameliorates parkinsonism, while SIRT1 knockdown further aggravates PD phenotypes. Mechanistically, SIRT1 interacts with and deacetylates pyruvate kinase M2 (PKM2) at K135 and K206, thus leading to reduced PKM2 enzyme activity and lactate production, which eventually results in decreased glial activation in the brain. Administration of lactate in the brain recapitulates PD-like phenotypes. Furthermore, increased expression of PKM2 worsens PD symptoms, and, on the contrary, inhibition of PKM2 by shikonin or PKM2-IN-1 alleviates parkinsonism in mice. Collectively, our data indicate that excessive lactate in the brain might be involved in the progression of PD. By improving lactate homeostasis, SIRT1, together with PKM2, are likely drug targets for developing agents for the treatment of neurodegeneration in PD.

Chromatin lysine acylation: On the path to chromatin homeostasis and genome integrity

The fundamental role of cells in safeguarding the genome's integrity against DNA double-strand breaks (DSBs) is crucial for maintaining chromatin homeostasis and the overall genomic stability. Aberrant responses to DNA damage, known as DNA damage responses (DDRs), can result in genomic instability and contribute significantly to tumorigenesis. Unraveling the intricate mechanisms underlying DDRs following severe damage holds the key to identify therapeutic targets for cancer. Chromatin lysine acylation, encompassing diverse modifications such as acetylation, lactylation, crotonylation, succinylation, malonylation, glutarylation, propionylation, and butyrylation, has been extensively studied in the context of DDRs and chromatin homeostasis. Here, we delve into the modifying enzymes and the pivotal roles of lysine acylation and their crosstalk in maintaining chromatin homeostasis and genome integrity in response to DDRs. Moreover, we offer a comprehensive perspective and overview of the latest insights, driven primarily by chromatin acylation modification and associated regulators.

Integrative Analysis of Lactylome and Proteome of Hypertrophic Scar To Identify Pathways or Proteins Associated with Disease Development

Lactylation (Kla), a recently discovered post-translational modification derived from lactate, plays crucial roles in various cellular processes. However, the specific influence of lactylation on the biological processes underlying hypertrophic scar formation remains unclear. In this study, we present a comprehensive profiling of the lactylome and proteome in both hypertrophic scars and adjacent normal skin tissues. A total of 1023 Kla sites originating from 338 nonhistone proteins were identified based on lactylome analysis. Proteome analysis in hypertrophic scar and adjacent skin samples revealed the identification of 2008 proteins. It is worth noting that Kla exhibits a preference for genes associated with ribosome function as well as glycolysis/gluconeogenesis in both normal skin and hypertrophic scar tissues. Furthermore, the functional enrichment analysis demonstrated that differentially lactyled proteins are primarily involved in proteoglycans, HIF-1, and AMPK signaling pathways. The combined analysis of the lactylome and proteome data highlighted a significant upregulation of 14 lactylation sites in hypertrophic scar tissues. Overall, our investigation unveiled the significant involvement of protein lactylation in the regulation of ribosome function as well as glycolysis/gluconeogenesis, potentially contributing to the formation of hypertrophic scars.

Exercise training decreases lactylation and prevents myocardial ischemia-reperfusion injury by inhibiting YTHDF2

Exercise improves cardiac function and metabolism. Although long-term exercise leads to circulating and micro-environmental metabolic changes, the effect of exercise on protein post-translational lactylation modifications as well as its functional relevance is unclear. Here, we report that lactate can regulate cardiomyocyte changes by improving protein lactylation levels and elevating intracellular N6-methyladenosine RNA-binding protein YTHDF2. The intrinsic disorder region of YTHDF2 but not the RNA m6A-binding activity is indispensable for its regulatory function in influencing cardiomyocyte cell size changes and oxygen glucose deprivation/re-oxygenation (OGD/R)-stimulated apoptosis via upregulating Ras GTPase-activating protein-binding protein 1 (G3BP1). Downregulation of YTHDF2 is required for exercise-induced physiological cardiac hypertrophy. Moreover, myocardial YTHDF2 inhibition alleviated ischemia/reperfusion-induced acute injury and pathological remodeling. Our results here link lactate and lactylation modifications with RNA m6A reader YTHDF2 and highlight the physiological importance of this innovative post-transcriptional intrinsic regulation mechanism of cardiomyocyte responses to exercise. Decreasing lactylation or inhibiting YTHDF2/G3BP1 might represent a promising therapeutic strategy for cardiac diseases.

Exploration of TCM syndrome types of the material basis and risk prediction of Wilson disease liver fibrosis based on 1H NMR metabolomics

Wilson disease (WD) is an autosomal recessive disorder characterized by abnormal copper metabolism. The accumulation of copper in the liver can progress to liver fibrosis and, ultimately, cirrhosis, which is a primary cause of death in WD patients. Metabonomic technology offers an effective approach to investigate the traditional Chinese medicine (TCM) syndrome types of WD-related liver fibrosis by monitoring the alterations in small molecule metabolites within the body. In this study, we employed 1H-Nuclear Magnetic Resonance (1H NMR) metabonomics to assess the metabolic profiles associated with five TCM syndrome types of WD-related liver fibrosis and analyzed the diagnostic and predictive capabilities of various metabolites. The study found a variety of metabolites, each with varying levels of diagnostic and predictive capabilities. Furthermore, the discerned differential metabolic pathways were primarily associated with various pathways involving carbohydrate metabolism, amino acid metabolism, and lipid metabolism. This study has identified various characteristic metabolic markers and pathways associated with different TCM syndromes of liver fibrosis in WD, providing a substantial foundation for investigating the mechanisms underlying these TCM syndromes.

Gegen Qinlian decoction inhibited M1 macrophage polarization and ulcerative colitis progression through regulating histone lactylation

Ulcerative colitis (UC) is a persistent inflammatory condition affecting the bowels. Gegen Qinlian decoction (GQD) has been widely used in the therapy of gastrointestinal diseases. We investigated the protective impacts and mechanism of GQD against UC. To establish the UC model, dextran sulfate sodium (DSS) was utilized. The disease activity index (DAI), colon length and colonic pathology were assessed to examine the impacts of GQD on UC. The level of pan-lysine lactylation (Pan kla) and specific sites were detected using western blot. Then, the inflammatory factors and the oxidative stress parameters were measured via the corresponding kits, respectively. Our findings demonstrated that GQD suppressed the lactate generation and LDH activity. The western blot revealed that GQD inhibited the expression of Pan kla and specific sites of H3K18la, H3K23la, H4K8la, and H4K12la. Furthermore, the suppressive effects on inflammation and oxidative stress caused by GQD were counteracted upon the exogenous lactate. GQD suppressed the phenotypic differentiation of M1 macrophages by reducing the expression of M1 markers, which was also reversed by exogenous lactate. In conclusion, GQD effectively suppressed UC progression through histone lactylation. Our results broadened the theoretical basis for the clinical use of GQD.

A bright red fluorescent genetically encoded sensor for lactate imaging

Lactate plays a crucial role in energy metabolism and greatly impacts protein activities, exerting diverse physiological and pathological effects. Therefore, convenient lactate assays for tracking spatiotemporal dynamics in living cells are desirable. In this paper, we engineered and optimized a red fluorescent protein sensor for l-lactate named FiLa-Red. This indicator exhibited a maximal fluorescence change of 730 % and an apparent dissociation constant (Kd) of approximately 460 μM. By utilizing FiLa-Red and other sensors, we monitored energy metabolism in a multiplex manner by simultaneously tracking lactate and NAD+/NADH abundance in the cytoplasm, nucleus, and mitochondria. The FiLa-Red sensor is expected to be a useful tool for performing metabolic analysis in vitro, in living cells and in vivo.

The pyruvate dehydrogenase complex at the epigenetic crossroads of acetylation and lactylation

The pyruvate dehydrogenase complex (PDC) is remarkable for its size and structure as well as for its physiological and pathological importance. Its canonical location is in the mitochondrial matrix, where it primes the tricarboxylic acid (TCA) cycle by decarboxylating glycolytically-derived pyruvate to acetyl-CoA. Less well appreciated is its role in helping to shape the epigenetic landscape, from early development throughout mammalian life by its ability to "moonlight" in the nucleus, with major repercussions for human healthspan and lifespan. The PDC's influence on two crucial modifiers of the epigenome, acetylation and lactylation, is the focus of this brief review.

Histone lactylation-related genes correlate with the molecular patterns and functions of cancer-associated fibroblasts and have significant clinical implications in clear cell renal cell carcinoma

Recent research emphasised the indispensable role of histone lactylation in the activation of hepatic stellate cells. The VHL mutation is extremely common in clear cell renal cell carcinoma, which normally causes a metabolic shift in cancer cells and increases lactate production, eventually creating a lactate-enriched tumour microenvironment. Cancer-associated fibroblasts (CAFs) promote tumour progression, which is also vital in clear cell renal cell carcinoma. Therefore, this study investigated histone lactylation in CAFs and its impact on patient survival. Multiomics technology was employed to determine the role of histone lactylation-related genes in the evolution of CAFs which correlated with the function and molecular signatures of CAFs. The results suggested that TIMP1 was the hub gene of histone lactylation-related genes in clear cell renal cell carcinoma.

H3K18 lactylation accelerates liver fibrosis progression through facilitating SOX9 transcription

Liver fibrosis is a significant health concern globally due to its association with severe liver conditions like cirrhosis and liver cancer. Histone lactylation has been implicated in the progression of hepatic fibrosis, but its specific role in liver fibrosis, particularly regarding H3K18 lactylation, remained unclear. To investigate this, we established in vivo and in vitro models of liver fibrosis using carbon tetrachloride (CCl4) injection in rats and stimulation of hepatic stellate cells (HSCs) with TGF-β1, respectively. We found that histone lactylation, particularly H3K18 lactylation, was upregulated in both CCl4-induced rats and TGF-β1-activated HSCs, indicating its potential involvement in liver fibrosis. Further experiments revealed that lactate dehydrogenase A (LDHA) knockdown inhibited H3K18 lactylation and had a beneficial effect on liver fibrosis by suppressing HSC proliferation, migration, and extracellular matrix (ECM) deposition. This suggests that H3K18 lactylation promotes liver fibrosis progression. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated that H3K18 lactylation facilitated the transcription of SOX9, a transcription factor associated with fibrosis. Importantly, overexpression of SOX9 counteracted the effects of LDHA silencing on activated HSCs, indicating that SOX9 is downstream of H3K18 lactylation in promoting liver fibrosis. In summary, this study uncovers a novel mechanism by which H3K18 lactylation contributes to liver fibrosis by activating SOX9 transcription. This finding opens avenues for exploring new therapeutic strategies for hepatic fibrosis targeting histone lactylation pathways.

The relationship and clinical significance of lactylation modification in digestive system tumors

Lactylation, an emerging post-translational modification, plays a pivotal role in the initiation and progression of digestive system tumors. This study presents a comprehensive review of lactylation in digestive system tumors, underscoring its critical involvement in tumor development and progression. By focusing on metabolic reprogramming, modulation of the tumor microenvironment, and the molecular mechanisms regulating tumor progression, the potential of targeting lactylation as a therapeutic strategy is highlighted. The research reveals that lactylation participates in gene expression regulation and cell signaling by affecting the post-translational states of histones and non-histone proteins, thereby influencing metabolic pathways and immune evasion mechanisms in tumor cells. Furthermore, this study assesses the feasibility of lactylation as a therapeutic target, providing insights for clinical treatment of gastrointestinal cancers. Future research should concentrate on elucidating the mechanisms of lactylation, developing efficient lactylation inhibitors, and validating their therapeutic efficacy in clinical trials, which could transform current cancer treatment and immunotherapy approaches. In summary, this review emphasizes the crucial role of lactylation in tumorigenesis and progression through a detailed analysis of its molecular mechanisms and clinical significance.

Metabolic reprogramming in liver fibrosis

Chronic liver diseases, primarily metabolic dysfunction-associated steatotic liver disease (MASLD), harmful use of alcohol, or viral hepatitis, may result in liver fibrosis, cirrhosis, and cancer. Hepatic fibrogenesis is a complex process with interactions between different resident and non-resident heterogeneous liver cell populations, ultimately leading to deposition of extracellular matrix and organ failure. Shifts in cell phenotypes and functions involve pronounced transcriptional and protein synthesis changes that require metabolic adaptations in cellular substrate metabolism, including glucose and lipid metabolism, resembling changes associated with the Warburg effect in cancer cells. Cell activation and metabolic changes are regulated by metabolic stress responses, including the unfolded protein response, endoplasmic reticulum stress, autophagy, ferroptosis, and nuclear receptor signaling. These metabolic adaptations are crucial for inflammatory and fibrogenic activation of macrophages, lymphoid cells, and hepatic stellate cells. Modulation of these pathways, therefore, offers opportunities for novel therapeutic approaches to halt or even reverse liver fibrosis progression.

Role of lactate and lactate metabolism in liver diseases (Review)

Lactate is a byproduct of glycolysis, and before the Warburg effect was revealed (in which glucose can be fermented in the presence of oxygen to produce lactate) it was considered a metabolic waste product. At present, lactate is not only recognized as a metabolic substrate that provides energy, but also as a signaling molecule that regulates cellular functions under pathophysiological conditions. Lactylation, a post‑translational modification, is involved in the development of various diseases, including inflammation and tumors. Liver disease is a major health challenge worldwide. In normal liver, there is a net lactate uptake caused by gluconeogenesis, exhibiting a higher net lactate clearance rate compared with any other organ. Therefore, abnormalities of lactate and lactate metabolism lead to the development of liver disease, and lactate and lactate metabolism‑related genes can be used for predicting the prognosis of liver disease. Targeting lactate production, regulating lactate transport and modulating lactylation may be potential treatment approaches for liver disease. However, currently there is not a systematic review that summarizes the role of lactate and lactate metabolism in liver diseases. In the present review, the role of lactate and lactate metabolism in liver diseases including liver fibrosis, non‑alcoholic fatty liver disease, acute liver failure and hepatocellular carcinoma was summarized with the aim to provide insights for future research.

Comprehensive review of histone lactylation: Structure, function, and therapeutic targets

Histone lysine lactylation (Kla) has emerged as a distinct epigenetic modification that differs markedly from established acylation modifications through the unique addition of a lactyl group to a lysine residue. Such modifications not only alter nucleosome structure but also significantly impact chromatin dynamics and gene expression, thus playing a crucial role in cellular metabolism, inflammatory responses, and embryonic development. The association of histone Kla with various metabolic processes, particularly glycolysis and glutamine metabolism, underscores its pivotal role in metabolic reprogramming, including in cancerous tissues, where it contributes to tumorigenesis, immune evasion, and angiogenesis. In addition, histone Kla is involved in the pathogenesis of various diseases, particularly several cancers and neurodegenerative diseases. The identification of histone Kla opens new avenues for therapeutic interventions targeting specific Kla sites. In this review, we summarize the differences between histone Kla modifications and other acylation modifications, discuss the mechanisms and roles of histone Kla in disease, and conclude by describing existing drugs and potential targets. This study provides new insights into the mechanisms linking histone Kla to diseases and into the discovery of new drugs and targets.

The characterization of protein lactylation in relation to cardiac metabolic reprogramming in neonatal mouse hearts

In mammals, the neonatal heart can regenerate upon injury within a short time after birth, while adults lose this ability. Metabolic reprogramming has been demonstrated to be critical for cardiomyocyte proliferation in the neonatal heart. Here, we reveal that cardiac metabolic reprogramming could be regulated by altering global protein lactylation. By performing 4D label-free proteomics and lysine lactylation (Kla) omics analyses in mouse hearts at postnatal days 1, 5, and 7, 2297 Kla sites from 980 proteins are identified, among which 1262 Kla sites from 409 proteins are quantified. Functional clustering analysis reveals that the proteins with altered Kla sites are mainly involved in metabolic processes. The expression and Kla levels of proteins in glycolysis show a positive correlation while a negative correlation in fatty acid oxidation. Furthermore, we verify the Kla levels of several differentially modified proteins, including ACAT1, ACADL, ACADVL, PFKM, PKM, and NPM1. Overall, our study reports a comprehensive Kla map in the neonatal mouse heart, which will help to understand the regulatory network of metabolic reprogramming and cardiac regeneration.

Histone H3K18 and Ezrin Lactylation Promote Renal Dysfunction in Sepsis-Associated Acute Kidney Injury

Histone lactylation is a metabolic stress-related histone modification. However, the role of histone lactylation in the development of sepsis-associated acute kidney injury (SA-AKI) remains unclear. Here, histone H3K18 lactylation (H3K18la) is elevated in SA-AKI, which is reported in this study. Furthermore, this lactate-dependent histone modification is enriched at the promoter of Ras homolog gene family member A (RhoA) and positively correlated with the transcription. Correction of abnormal lactate levels resulted in a reversal of abnormal histone lactylation at the promoter of RhoA. Examination of related mechanism revealed that histone lactylation promoted the RhoA/Rho-associated protein kinase (ROCK) /Ezrin signaling, the activation of nuclear factor-κB (NF-κB), inflammation, cell apoptosis, and aggravated renal dysfunction. In addition, Ezrin can undergo lactylation modification. Multiple lactylation sites are identified in Ezrin and confirmed that lactylation mainly occurred at the K263 site. The role of histone lactylation is revealed in SA-AKI and reportes a novel post-translational modification in Ezrin. Its potential role in regulating inflammatory metabolic adaptation of renal proximal tubule epithelial cells is also elucidated. The results provide novel insights into the epigenetic regulation of the onset of SA-AKI.

Glycolysis in hepatic stellate cells coordinates fibrogenic extracellular vesicle release spatially to amplify liver fibrosis

Liver fibrosis is characterized by the activation of perivascular hepatic stellate cells (HSCs), the release of fibrogenic nanosized extracellular vesicles (EVs), and increased HSC glycolysis. Nevertheless, how glycolysis in HSCs coordinates fibrosis amplification through tissue zone-specific pathways remains elusive. Here, we demonstrate that HSC-specific genetic inhibition of glycolysis reduced liver fibrosis. Moreover, spatial transcriptomics revealed a fibrosis-mediated up-regulation of EV-related pathways in the liver pericentral zone, which was abrogated by glycolysis genetic inhibition. Mechanistically, glycolysis in HSCs up-regulated the expression of EV-related genes such as Ras-related protein Rab-31 (RAB31) by enhancing histone 3 lysine 9 acetylation on the promoter region, which increased EV release. Functionally, these glycolysis-dependent EVs increased fibrotic gene expression in recipient HSC. Furthermore, EVs derived from glycolysis-deficient mice abrogated liver fibrosis amplification in contrast to glycolysis-competent mouse EVs. In summary, glycolysis in HSCs amplifies liver fibrosis by promoting fibrogenic EV release in the hepatic pericentral zone, which represents a potential therapeutic target.

Lactylation: The emerging frontier in post-translational modification

Lactate, a metabolic byproduct, has gained recognition as a highly influential signaling molecule. Lactylation, an emerging form of post-translational modification derived from lactate, plays a crucial role in numerous cellular processes such as inflammation, embryonic development, tumor proliferation, and metabolism. However, the precise molecular mechanisms through which lactylation governs these biological functions in both physiological and pathological contexts remain elusive. Hence, it is imperative to provide a comprehensive overview of lactylation in order to elucidate its significance in biological processes and establish a foundation for forthcoming investigations. This review aims to succinctly outline the process of lactylation modification and the characterization of protein lactylation across diverse organisms. Additionally, A summary of the regulatory mechanisms of lactylation in cellular processes and specific diseases is presented. Finally, this review concludes by delineating existing research gaps in lactylation and proposing primary directions for future investigations.

The walnut-derived peptide TW-7 improves mouse parthenogenetic embryo development of vitrified MII oocytes potentially by promoting histone lactylation

BACKGROUND

Previous studies have shown that the vitrification of metaphase II (MII) oocytes significantly represses their developmental potential. Abnormally increased oxidative stress is the probable factor; however, the underlying mechanism remains unclear. The walnut-derived peptide TW-7 was initially isolated and purified from walnut protein hydrolysate. Accumulating evidences implied that TW-7 was a powerful antioxidant, while its prospective application in oocyte cryopreservation has not been reported.

RESULT

Here, we found that parthenogenetic activation (PA) zygotes derived from vitrified MII oocytes showed elevated ROS level and delayed progression of pronucleus formation. Addition of 25 μmol/L TW-7 in warming, recovery, PA, and embryo culture medium could alleviate oxidative stress in PA zygotes from vitrified mouse MII oocytes, furtherly increase proteins related to histone lactylation such as LDHA, LDHB, and EP300 and finally improve histone lactylation in PA zygotes. The elevated histone lactylation facilitated the expression of minor zygotic genome activation (ZGA) genes and preimplantation embryo development.

CONCLUSIONS

Our findings revealed the mechanism of oxidative stress inducing repressed development of PA embryos from vitrified mouse MII oocytes and found a potent and easy-obtained short peptide that could significantly rescue the decreased developmental potential of vitrified oocytes, which would potentially contribute to reproductive medicine, animal protection, and breeding.

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

O-GlcNAcylation controls pro-fibrotic transcriptional regulatory signaling in myofibroblasts

Tissue injury causes activation of mesenchymal lineage cells into wound-repairing myofibroblasts (MFs), whose uncontrolled activity ultimately leads to fibrosis. Although this process is triggered by deep metabolic and transcriptional reprogramming, functional links between these two key events are not yet understood. Here, we report that the metabolic sensor post-translational modification O-linked β-D-N-acetylglucosaminylation (O-GlcNAcylation) is increased and required for myofibroblastic activation. Inhibition of protein O-GlcNAcylation impairs archetypal myofibloblast cellular activities including extracellular matrix gene expression and collagen secretion/deposition as defined in vitro and using ex vivo and in vivo murine liver injury models. Mechanistically, a multi-omics approach combining proteomic, epigenomic, and transcriptomic data mining revealed that O-GlcNAcylation controls the MF transcriptional program by targeting the transcription factors Basonuclin 2 (BNC2) and TEA domain transcription factor 4 (TEAD4) together with the Yes-associated protein 1 (YAP1) co-activator. Indeed, inhibition of protein O-GlcNAcylation impedes their stability leading to decreased functionality of the BNC2/TEAD4/YAP1 complex towards promoting activation of the MF transcriptional regulatory landscape. We found that this involves O-GlcNAcylation of BNC2 at Thr455 and Ser490 and of TEAD4 at Ser69 and Ser99. Altogether, this study unravels protein O-GlcNAcylation as a key determinant of myofibroblastic activation and identifies its inhibition as an avenue to intervene with fibrogenic processes.

Esculin inhibits hepatic stellate cell activation and CCl4-induced liver fibrosis by activating the Nrf2/GPX4 signaling pathway

BACKGROUND

Liver fibrosis (LF) is a pathological process of the liver that threatens human health. Currently, effective treatments are still lacking. Esculin, a prominent constituent found in the Fraxinus rhynchophylla. (bark), Aesculus hippocastanum. (bark), and Cichorium intybus. (herb), has been shown to possess significant anti-inflammatory, antioxidant, and antibacterial properties. However, to date, there have been no studies investigating its potential efficacy in the treatment of LF.

OBJECTIVE

The study aims to investigate the therapeutic effect of esculin on LF and elucidate its potential molecular mechanism.

METHODS

Carbon tetrachloride (CCl4) was injected intraperitoneally to induce LF in mice, and transforming growth factor β1 (TGF-β1) was injected to induce LX-2 cells to investigate the improvement effect of esculin on LF. Kit, histopathological staining, immunohistochemistry (IHC), immunofluorescence (IF), polymerase chain reaction (PCR), and western blot (WB) were used to detect the expression of fiber markers and nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPX4) signaling pathway in liver tissue and LX-2 cells. Finally, molecular docking, cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) were used to verify the targeting between Nrf2 and esculin.

RESULTS

Esculin significantly inhibited CCl4-induced hepatic fibrosis and inflammation in mice. This was evidenced by the improvement of liver function indexes, fibrosis indicators, and histopathology. Additionally, esculin treatment prominently reduced the levels of pro-inflammatory factors, oxidative stress, and liver Fe2+ in CCl4-induced mice. In vitro studies also showed that esculin treatment significantly inhibited TGF-β1-induced LX-2 cell activation and decreased alpha-smooth muscle actin (α-SMA) and collagen I expression. Mechanism experiments proved that esculin can activate the Nrf2/GPX4 signaling pathway and inhibit liver ferroptosis. However, when LX-2 cells were treated with the Nrf2 inhibitor (ML385), the therapeutic effect of esculin significantly decreased.

CONCLUSION

This study is the first to demonstrate that esculin is a potential natural active ingredient in the treatment of LF, which can inhibit the activation of hepatic stellate cells (HSC) and improve LF. Its therapeutic effect is related to the activation of the Nrf2/GPX4 signaling pathway.

Lactylation: the novel histone modification influence on gene expression, protein function, and disease

Lactic acid, traditionally considered as a metabolic waste product arising from glycolysis, has undergone a resurgence in scientific interest since the discovery of the Warburg effect in tumor cells. Numerous studies have proved that lactic acid could promote angiogenesis and impair the function of immune cells within tumor microenvironments. Nevertheless, the precise molecular mechanisms governing these biological functions remain inadequately understood. Recently, lactic acid has been found to induce a posttranslational modification, lactylation, that may offer insight into lactic acid's non-metabolic functions. Notably, the posttranslational modification of proteins by lactylation has emerged as a crucial mechanism by which lactate regulates cellular processes. This article provides an overview of the discovery of lactate acidification, outlines the potential "writers" and "erasers" responsible for protein lactylation, presents an overview of protein lactylation patterns across different organisms, and discusses the diverse physiological roles of lactylation. Besides, the article highlights the latest research progress concerning the regulatory functions of protein lactylation in pathological processes and underscores its scientific significance for future investigations.

The emerging role of lactate in tumor microenvironment and its clinical relevance

In recent years, the significant impact of lactate in the tumor microenvironment has been greatly documented. Acting not only as an energy substance in tumor metabolism, lactate is also an imperative signaling molecule. It plays key roles in metabolic remodeling, protein lactylation, immunosuppression, drug resistance, epigenetics and tumor metastasis, which has a tight relation with cancer patients' poor prognosis. This review illustrates the roles lactate plays in different aspects of tumor progression and drug resistance. From the comprehensive effects that lactate has on tumor metabolism and tumor immunity, the therapeutic targets related to it are expected to bring new hope for cancer therapy.

Treatment of Donor Cells with Oxidative Phosphorylation Inhibitor CPI Enhances Porcine Cloned Embryo Development

Somatic cell nuclear transfer (SCNT) technology holds great promise for livestock industry, life science and human biomedicine. However, the development and application of this technology is limited by the low developmental potential of SCNT embryos. The developmental competence of cloned embryos is influenced by the energy metabolic status of donor cells. The purpose of this study was to investigate the effects of CPI, an oxidative phosphorylation inhibitor, on the energy metabolism pathways of pig fibroblasts and the development of subsequent SCNT embryos. The results showed that treatment of porcine fibroblasts with CPI changed the cellular energy metabolic pathways from oxidative phosphorylation to glycolysis and enhanced the developmental ability of subsequent SCNT embryos. The present study establishes a simple, new way to improve pig cloning efficiency, helping to promote the development and application of pig SCNT technology.

Augmentation of scleral glycolysis promotes myopia through histone lactylation

Myopia is characterized of maladaptive increases in scleral fibroblast-to-myofibroblast transdifferentiation (FMT). Scleral hypoxia is a significant factor contributing to myopia, but how hypoxia induces myopia is poorly understood. Here, we showed that myopia in mice and guinea pigs was associated with hypoxia-induced increases in key glycolytic enzymes expression and lactate levels in the sclera. Promotion of scleral glycolysis or lactate production induced FMT and myopia; conversely, suppression of glycolysis or lactate production eliminated or inhibited FMT and myopia. Mechanistically, increasing scleral glycolysis-lactate levels promoted FMT and myopia via H3K18la, and this promoted Notch1 expression. Genetic analyses identified a significant enrichment of two genes encoding glycolytic enzymes, ENO2 and TPI1. Moreover, increasing sugar intake in guinea pigs not only induced myopia but also enhanced the response to myopia induction via the scleral glycolysis-lactate-histone lactylation pathway. Collectively, we suggest that scleral glycolysis contributes to myopia by promoting FMT via lactate-induced histone lactylation.

The m6A reader IGF2BP2 regulates glycolytic metabolism and mediates histone lactylation to enhance hepatic stellate cell activation and liver fibrosis

Evidence for the involvement of N6-Methyladenosine (m6A) modification in the etiology and progression of liver fibrosis has emerged and holds promise as a therapeutic target. Insulin-like growth factor 2 (IGF2) mRNA-binding protein 2 (IGF2BP2) is a newly identified m6A-binding protein that functions to enhance mRNA stability and translation. However, its role as an m6A-binding protein in liver fibrosis remains elusive. Here, we observed that IGF2BP2 is highly expressed in liver fibrosis and activated hepatic stellate cells (HSCs), and inhibition of IGF2BP2 protects against HSCs activation and liver fibrogenesis. Mechanistically, as an m6A-binding protein, IGF2BP2 regulates the expression of Aldolase A (ALDOA), a key target in the glycolytic metabolic pathway, which in turn regulates HSCs activation. Furthermore, we observed that active glycolytic metabolism in activated HSCs generates large amounts of lactate as a substrate for histone lactylation. Importantly, histone lactylation transforms the activation phenotype of HSCs. In conclusion, our findings reveal the essential role of IGF2BP2 in liver fibrosis by regulating glycolytic metabolism and highlight the potential of targeting IGF2BP2 as a therapeutic for liver fibrosis.

Ubiquitous protein lactylation in health and diseases

For decades, lactate has been considered a byproduct of glycolysis. The lactate shuttle hypothesis shifted the lactate paradigm, demonstrating that lactate not only plays important roles in cellular metabolism but also cellular communications, which can transcend compartment barriers and can occur within and among different cells, tissues and organs. Recently, the discovery that lactate can induce a novel post-translational modification, named lysine lactylation (Kla), brings forth a new avenue to study nonmetabolic functions for lactate, which has inspired a 'gold rush' of academic and commercial interest. Zhang et al. first showed that Kla is manifested in histones as epigenetic marks, and then mounting evidences demonstrated that Kla also occurs in diverse non-histone proteins. The widespread Kla faithfully orchestrates numerous biological processes, such as transcription, metabolism and inflammatory responses. Notably, dysregulation of Kla touches a myriad of pathological processes. In this review, we comprehensively reviewed and curated the existing literature to retrieve the new identified Kla sites on both histones and non-histone proteins and summarized recent major advances toward its regulatory mechanism. We also thoroughly investigated the function and underlying signaling pathway of Kla and comprehensively summarize how Kla regulates various biological processes in normal physiological states. In addition, we also further highlight the effects of Kla in the development of human diseases including inflammation response, tumorigenesis, cardiovascular and nervous system diseases and other complex diseases, which might potentially contribute to deeply understanding and interpreting the mechanism of its pathogenicity.

The novel mechanism facilitating chronic hepatitis B infection: immunometabolism and epigenetic modification reprogramming

Hepatitis B Virus (HBV) infections pose a global public health challenge. Despite extensive research on this disease, the intricate mechanisms underlying persistent HBV infection require further in-depth elucidation. Recent studies have revealed the pivotal roles of immunometabolism and epigenetic reprogramming in chronic HBV infection. Immunometabolism have identified as the process, which link cell metabolic status with innate immunity functions in response to HBV infection, ultimately contributing to the immune system's inability to resolve Chronic Hepatitis B (CHB). Within hepatocytes, HBV replication leads to a stable viral covalently closed circular DNA (cccDNA) minichromosome located in the nucleus, and epigenetic modifications in cccDNA enable persistence of infection. Additionally, the accumulation or depletion of metabolites not only directly affects the function and homeostasis of immune cells but also serves as a substrate for regulating epigenetic modifications, subsequently influencing the expression of antiviral immune genes and facilitating the occurrence of sustained HBV infection. The interaction between immunometabolism and epigenetic modifications has led to a new research field, known as metabolic epigenomics, which may form a mutually reinforcing relationship with CHB. Herein, we review the recent studies on immunometabolism and epigenetic reprogramming in CHB infection and discuss the potential mechanisms of persistent HBV infection. A deeper understanding of these mechanisms will offer novel insights and targets for intervention strategies against chronic HBV infection, thereby providing new hope for the treatment of related diseases.

Salvianolic Acid B Alleviates Liver Injury by Regulating Lactate-Mediated Histone Lactylation in Macrophages

Salvianolic acid B (Sal B) is the primary water-soluble bioactive constituent derived from the roots of Salvia miltiorrhiza Bunge. This research was designed to reveal the potential mechanism of Sal B anti-liver injury from the perspective of macrophages. In our lipopolysaccharide-induced M1 macrophage model, Sal B showed a clear dose-dependent gradient of inhibition of the macrophage trend of the M1 type. Moreover, Sal B downregulated the expression of lactate dehydrogenase A (LDHA), while the overexpression of LDHA impaired Sal B's effect of inhibiting the trend of macrophage M1 polarization. Additionally, this study revealed that Sal B exhibited inhibitory effects on the lactylation process of histone H3 lysine 18 (H3K18la). In a ChIP-qPCR analysis, Sal B was observed to drive a reduction in H3K18la levels in the promoter region of the LDHA, NLRP3, and IL-1β genes. Furthermore, our in vivo experiments showed that Sal B has a good effect on alleviating CCl4-induced liver injury. An examination of liver tissues and the Kupffer cells isolated from those tissues proved that Sal B affects the M1 polarization of macrophages and the level of histone lactylation. Together, our data reveal that Sal B has a potential mechanism of inhibiting the histone lactylation of macrophages by downregulating the level of LDHA in the treatment of liver injury.

The role of lactate in cardiovascular diseases

Cardiovascular diseases pose a major threat worldwide. Common cardiovascular diseases include acute myocardial infarction (AMI), heart failure, atrial fibrillation (AF) and atherosclerosis. Glycolysis process often has changed during these cardiovascular diseases. Lactate, the end-product of glycolysis, has been overlooked in the past but has gradually been identified to play major biological functions in recent years. Similarly, the role of lactate in cardiovascular disease is gradually being recognized. Targeting lactate production, regulating lactate transport, and modulating circulating lactate levels may serve as potential strategies for the treatment of cardiovascular diseases in the future. The purpose of this review is to integrate relevant clinical and basic research on the role of lactate in the pathophysiological process of cardiovascular disease in recent years to clarify the important role of lactate in cardiovascular disease and to guide further studies exploring the role of lactate in cardiovascular and other diseases. Video Abstract.

Oncometabolite lactate enhances breast cancer progression by orchestrating histone lactylation-dependent c-Myc expression

Due to the enhanced glycolytic rate, cancer cells generate lactate copiously, subsequently promoting the lactylation of histones. While previous studies have explored the impact of histone lactylation in modulating gene expression, the precise role of this epigenetic modification in regulating oncogenes is largely unchartered. In this study, using breast cancer cell lines and their mutants exhibiting lactate-deficient metabolome, we have identified that an enhanced rate of aerobic glycolysis supports c-Myc expression via promoter-level histone lactylation. Interestingly, c-Myc further transcriptionally upregulates serine/arginine splicing factor 10 (SRSF10) to drive alternative splicing of MDM4 and Bcl-x in breast cancer cells. Moreover, our results reveal that restricting the activity of critical glycolytic enzymes affects the c-Myc-SRSF10 axis to subside the proliferation of breast cancer cells. Our findings provide novel insights into the mechanisms by which aerobic glycolysis influences alternative splicing processes that collectively contribute to breast tumorigenesis. Furthermore, we also envisage that chemotherapeutic interventions attenuating glycolytic rate can restrict breast cancer progression by impeding the c-Myc-SRSF10 axis.