H3K18 lactylation marks tissue-specific active enhancers

Turning sour into sweet: Lactylation modification as a promising target in cardiovascular health

Lactylation, a recently identified posttranslational modification (PTM), has emerged as a critical regulatory mechanism in cardiovascular diseases (CVDs). This PTM involves the addition of lactyl groups to lysine residues on histones and nonhistone proteins, influencing gene expression and cellular metabolism. The discovery of lactylation has revealed new directions for understanding metabolic and immune processes, particularly in the context of CVDs. This review describes the intricate roles of specific lactylated proteins and enzymes, such as H3K18, HMGB1, MCT1/4, and LDH, in the regulation of cardiovascular pathology. This study also highlights the unique impact of lactylation on myocardial hypertrophy and distinguishes it from other PTMs, such as SUMOylation and acetylation, underscoring its potential as a therapeutic target. Emerging drugs targeting lactate transporters and critical enzymes involved in lactylation offer promising avenues for novel CVD therapies. This review calls for further research to elucidate the mechanisms linking lactylation to CVDs, emphasizing the need for comprehensive studies at the molecular, cellular, and organismal levels to pave the way for innovative preventive, diagnostic, and treatment strategies in cardiovascular medicine.

Oxidative stress and central metabolism pathways impact epigenetic modulation in inflammation and immune response

Oxidative stress, metabolism, and epigenetics are deeply interconnected processes that collectively influence cellular function, health status, and contribute to disease progression. This review highlights the critical role of metabolic intermediates in epigenetic regulation, focusing on lactate, glutathione (GSH), and S-adenosylmethionine (SAM). Beyond its traditional role in energy metabolism, lactate modulates epigenetic mechanisms, influencing gene expression and cellular adaptation. Meanwhile, GSH and SAM serve as key regulators of DNA methylation and histone post-translational modifications, maintaining epigenetic homeostasis. These processes are tightly controlled by redox balance and oxidative stress, underscoring the intricate interplay between metabolism and epigenetic regulation. GSH depletion disrupts methylation homeostasis, while oxidative post-translational modifications (oxPTMs) on histones-including S-glutathionylation, carbonylation, and nitrosylation-alter chromatin architecture and transcriptional regulation. Additionally, we focus on histone lactylation, particularly its role in regulating innate and adaptive immune responses. We also explore how GSH and oxidative stress influence lactate levels, potentially inducing histone lactylation or S-glutathionylation through S,D-lactoylglutathione (LGSH), thereby impacting epigenetic regulation. By integrating insights into metabolic-epigenetic crosstalk, this review underscores the role of oxidative stress and central metabolic pathways in regulating epigenetic mechanisms, a concept known as "redox epigenetics." Understanding these intricate interactions offers new perspectives for therapeutic strategies aimed at restoring redox homeostasis and metabolic integrity to counteract disturbances in the epigenetic landscape.

Detecting the distribution patterns of histone lactylation in the mouse testis at different developmental stages

Lactate is a key glycolytic metabolite that serves as an energy substance and signaling molecule. Lactylation, a recently characterized posttranslational modification (PTM), has been identified in histone and nonhistone proteins. Compelling evidence suggests that this lactate-related epigenetic modification potently regulates gene expression under physiological and pathological conditions. However, the distribution of this histone modification in the testis remains largely unknown. In this study, we investigated the expression dynamics of histone acetyltransferases (HATs), histone deacetylases (HDACs), and the lactate-regulating enzyme hexokinase 2 (HK2), and examined the cellular distribution of several types of histone lactylation, which have been identified as important for transcription and chromatin accessibility, in mouse testes during critical postnatal developmental stages. The results revealed that the expression levels of the lactylation-associated transcripts were developmentally regulated and that the histone lactylation, including H3K9la, H3K12la and H4K18la were present in spermatogenic and Sertoli cells at postnatal days (PD) 0, 6, 21, and 60. However, signals for H3K5la and H3K14la were not detected in gonocytes at PD0 and signal for H3K14la was not detected in mature Sertoli cells or spermatogonia of adult testes. Furthermore, a lack of lactate dehydrogenase a (Ldha) in Sertoli cells impacted the localization of several histone lactylation modifications in spermatogenic cells. Notably, H4K12la was specifically detected in zygotene and diplotene spermatocytes in the control testis, whereas it was present mainly in spermatogonia of Lhda Sertoli cell conditional knockout testis (Ldha-cKO). The results of this study lay a foundation for further understanding the role of lactylation modification in spermatogenesis and provide important data for further dissectting the role of Sertoli cell-derived lactate in germ cell development.

Super-Enhancer-Driven LncRNA UNC5B-AS1 Inhibits Inflammatory Phenotypic Transition in Pulmonary Artery Smooth Muscle Cells via Lactylation

BACKGROUND

The phenotypic transition of pulmonary artery smooth muscle cells (PASMCs) is a central pathological alteration in pulmonary artery remodeling, contributing to pulmonary hypertension. Super-enhancers (SEs), characterized by histone modifications and the binding of coactivators, drive the expression of prominent genes that define cellular identity. However, the specific role of SEs, particularly SE-driven long noncoding RNAs, in hypoxia-induced phenotypic plasticity of PASMCs remains unclear.

METHODS

In this study, the long noncoding RNA UNC5B antisense RNA 1 (UNC5B-AS1) regulated by SEs was screened in hypoxic PASMCs using RNA sequencing and H3K27ac (histone 3 lysine 27 acetylation) chromatin immunoprecipitation sequencing. Overexpression or knockdown of UNC5B-AS1 in vitro was performed to elucidate its role in pulmonary hypertension pathogenesis. A serotype 5 adenovirus-associated virus carrying a conserved functional fragment of UNC5B-AS1 was used to treat pulmonary hypertension in vivo.

RESULTS

We identified UNC5B-AS1 as an SE-driven long noncoding RNA transcriptionally activated by the transcription factor FOXP3 (forkhead box protein P3), which regulates phenotypic transition in PASMCs. Notably, we demonstrated that UNC5B-AS1 interacts with key glycolytic enzymes in the cytoplasm and likely serves as a molecular scaffold for LRPPRC (leucine-rich PPR motif-containing protein) and oxidative respiratory chain complex IV in mitochondria. Consequently, the deficiency of UNC5B-AS1 in PASMCs promotes the lactylation of promoter regions within inflammatory genes, including those of IL (interleukin)-1β, IL-6, and TNF-α (tumor necrosis factor-α), under hypoxic conditions, ultimately leading to inflammatory phenotypic transition of PASMCs.

CONCLUSIONS

Our findings identify SE-driven UNC5B-AS1 as a novel regulatory factor in the hypoxia-induced phenotypic transition of PASMCs and suggest that overexpression of UNC5B-AS1 may represent a promising therapeutic strategy for pulmonary hypertension.

Cisplatin reduces immunosuppression caused by tumor-associated macrophages through downregulating CD47-SIRPα signaling in glioblastoma

The poor prognosis of glioblastoma (GBM) is partly attributed to the immunosuppressive microenvironment. The combination of standard temozolomide and other chemotherapy drugs can significantly enhance the therapeutic effect by reshaping the immune microenvironment. Cisplatin treatment induces immunogenic cell death in tumor cells, stimulating an immune response. Here, we investigated the immune-activating effect of cisplatin on tumor-associated macrophages (TAMs). The therapeutic benefit of temozolomide plus cisplatin was showed in a murine model of GBM, accompanied by the inhibition of tumor growth and enhancement of pro-inflammatory activation of TAMs. Furthermore, cisplatin treatment downregulated the expression of CD47 in glioma stem cells, SIRPα, and IL-6 in TAMs, thus promoting M1-like polarization of TAMs to enhance an immune-activating tumor microenvironment. Mechanically, cisplatin decreases the production of lactic acid by downregulating LDHA expression. A low level of lactate reduces histone H3K18 lactylation on the CD47 and IL-6 promoters, thereby suppressing gene transcription. Our study reveals a new mechanism by which cisplatin remodels the immune tumor microenvironment, suggesting that combining temozolomide with cisplatin chemotherapy may be a new treatment option for GBM.

Long-term histone lactylation connects metabolic and epigenetic rewiring in innate immune memory

Trained immunity, a de facto innate immune memory characterized by enhanced responsiveness to future challenges, is underpinned by epigenetic and metabolic rewiring. In individuals vaccinated with Bacille Calmette-Guérin (BCG), lactate release was associated with enhanced cytokine responsiveness upon restimulation. Trained monocytes/macrophages are characterized by lactylation of histone H3 at lysine residue 18(H3K18la), mainly at distal regulatory regions. Histone lactylation was positively associated with active chromatin and gene transcription, persisted after the elimination of the training stimulus, and was strongly associated with "trained" gene transcription in response to a secondary stimulus. Increased lactate production upon induction of trained immunity led to enhanced production of proinflammatory cytokines, a process associated with histone lactylation. Pharmacological inhibition of lactate production or histone lactylation blocked trained immunity responses, while polymorphisms of LDHA and EP300 genes modulated trained immunity. Long-term histone lactylation persisted in vivo 90 days after vaccination with BCG, highlighting H3K18la as an epigenetic mark of innate immune memory.

SIRT3 Functions as an Eraser of Histone H3K9 Lactylation to Modulate Transcription for Inhibiting the Progression of Esophageal Cancer

Lysine lactylation (Kla) links lactate metabolism to epigenetic regulation, playing a key role in modulation of gene expression in tumor and immune microenvironment. Our recent study shows that HBO1-mediated histone H3K9la activates the transcription of genes encoding tumorigenesis, suggesting the potential significance of intervening in this Kla site for tumor therapy. Evidence so far indicates that traditional deacetylases can catalyze the removal of Kla; however, the precise demodifying enzyme to histone H3K9la in vivo and functional consequence remain elusive. Herein, we combined an antibody-based proximity labeling approach with mass spectrometry analysis to identify SIRT3 as a major binder to histone H3K9la and showed the specific catalysis of SIRT3 for the removal of lactylation. Molecular docking further revealed the molecular mechanism of the binding of histone H3K9la to SIRT3. More importantly, SIRT3 can specifically modulate gene transcription by regulating H3K9la, inhibiting the progression of esophageal squamous cancer cells. Together, our work identifies the specific delactylase of H3K9la and reveals an H3K9la-mediated molecular mechanism catalyzed by SIRT3 for gene transcription regulation in esophageal squamous cancer cells, and our findings provide an opportunity to investigate the physiological significance of Kla controlled by SIRT3 in cancer.

The Functions and Regulatory Mechanisms of Histone Modifications in Skeletal Muscle Development and Disease

Skeletal muscle development is a complex biological process regulated by many factors, such as transcription factors, signaling pathways, and epigenetic modifications. Histone modifications are important epigenetic regulatory factors involved in various biological processes, including skeletal muscle development, and play a crucial role in the pathogenesis of skeletal muscle diseases. Histone modification regulators affect the expression of many genes involved in skeletal muscle development and disease by adding or removing certain chemical modifications. In this review, we comprehensively summarize the functions and regulatory activities of the histone modification regulators involved in skeletal muscle development, regeneration, and disease.

March2 Alleviates Aortic Aneurysm/Dissection by Regulating PKM2 Polymerization

BACKGROUND

Aortic aneurysm/dissection (AAD) is a life-threatening disease lacking effective pharmacological treatment. Protein ubiquitination plays a pivotal role in cardiovascular diseases. However, the possible contribution of the E3 ubiquitin ligase March2 (membrane-associated RING [really interesting new gene] finger protein 2) to the cause of AAD remains elusive.

METHODS

Integrated single-cell RNA sequencing analysis was conducted in human AAD tissues. Based on the screening results, we generated a mouse line of smooth muscle cell-specific March2 knockout. β-Aminopropionitrile monofumarate was used to establish AAD. Cleavage under targets and tagmentation and cleavage under targets and tagmentation-quantitative polymerase chain reaction were performed to identify possible target genes for histone H3K18 lactylation.

RESULTS

March2 expression was downregulated in aorta from patients with AAD or β-aminopropionitrile monofumarate-induced AAD mice. β-Aminopropionitrile monofumarate-induced AAD was significantly accentuated in March2 global (March2-/-) and vascular smooth muscle cell-specific deletion (March2fl/fl; TaglnCre) mice, whereas the AAD pathology was rescued by rAAV9-SM22α (smooth muscle 22α)-March2 (recombinant adeno-associated virus serotype 9 expressing Flag-tagged March2 under SM22α promoter). March2 interacted with PKM2 (pyruvate kinase M2) to promote K33-linked polyubiquitination. Deficiency of March2 lessened PKM2 dimer-to-tetramer conversion in AAD and overtly exacerbated AAD-induced histone H3K18 lactylation in vascular smooth muscle cells by fostering glucose metabolism reprogramming, thereby promoting p53-driven apoptotic transcriptional response-a hallmark of AAD pathogenesis. TEPP-46 (tetraethyl pyrophosphate), a PKM2-specific activator, pronouncedly alleviated March2 deficiency-deteriorated AAD pathology.

CONCLUSIONS

Our findings demonstrated that March2 is a novel endogenous defender that prevents AAD by inhibiting vascular smooth muscle cell apoptosis, suggesting that March2 represents a potential therapeutic target for AAD.

Targeting Lactic Acid Modification in Ischemic Heart Diseases: Novel Therapeutics and Mechanism

Ischemic heart disease (IHD), especially acute myocardial infarction (AMI), has a high mortality rate and poses a great threat to human health. When myocardial infarction occurs, the structure and function of the myocardium are significantly damaged, and its metabolisms switch from oxidative phosphorylation to glycolysis, producing lactate. Lactylation, as a newly discovered post-translational modification (PMT) in recent years, is involved in the regulation of gene expression, and cell proliferation. Emerging studies have revealed that lactate and lactylation modifications participate in inflammation and cardiac repair, and play an important role in cardiovascular diseases, such as myocardial infarction, myocardial fibrosis, and heart failure. Therefore, in this review, we discuss how glucose metabolism, glycolytic end-product lactate, and lactylation potentially interact with pathological processes, including inflammation, cardiac fibrosis, and heart failure. And targeting glycolysis and lactylation modification could provide a promising future for cardiovascular diseases.

Histone H2B lysine lactylation modulates the NF-κB response via KPNA2 during CSFV infection

Histone lysine lactylation (Kla) has recently been reported to participate in various biological processes, regulating transcription, inflammation, and immune-related diseases. However, the mechanism of histone Kla in innate immunity and viral infection remains largely unknown. Here, we observed fluorescent Kla signals in all four histones (H2A, H2B, H3, and H4) in PK-15 cells. Immunoprecipitation analysis showed prominent histone Kla protein bands, with H2B being the most abundant. We generated the H2B K16R mutant plasmid and identified K16 as one of the Kla modification sites in H2B. Further exploration revealed increased global H2B Kla and H2BK16la levels upon classical swine fever virus (CSFV) infection. By employing the Kla agonist (L-lactate), inhibitor (oxamate), or siLDHA, we demonstrated that H2BK16la and pan Kla in PK-15 cells rely on the LDHA-lactate axis, which is also crucial for CSFV-induced H2BK16la and pan Kla levels. Moreover, our data proved the interaction between H2B and CSFV NS4A protein. Notably, H2B Kla can modulate CSFV proliferation. Mechanistically, H2BK16la and pan Kla activate the nuclear factor kappa B (NF-κB) pathway by mediating p65 nuclear translocation via karyopherin α2 (KPNA2), thereby inducing type III interferon (IFN-λ) expression and inhibiting CSFV replication. In conclusion, our study unveils the role of H2B Kla in regulating the NF-κB pathway during viral infection, presenting a novel mechanism. These findings significantly contribute to understanding the pathogenic mechanisms during viral infection and hold promise for the development of viral therapeutic strategies.

Cellular and Molecular Mechanisms of Innate Memory Responses

There has been an increasing effort to understand the memory responses of a complex interplay among innate, adaptive, and structural cells in peripheral organs and bone marrow. Trained immunity is coined as the de facto memory of innate immune cells and their progenitors. These cells acquire epigenetic modifications and shift their metabolism to equip an imprinted signature to a persistent fast-responsive functional state. Recent studies highlight the contribution of noncoding RNAs and modulation of chromatin structures in establishing this epigenetic readiness for potential immune perturbations. In this review, we discuss recent studies that highlight trained immunity-mediated memory responses emerging intrinsically in innate immune cells and as a complex interplay with other cells at the organ level. Lastly, we survey epigenetic contributors to trained immunity phenotypes-specifically, a recently discovered regulatory circuit coordinating the regulation of a key driver of trained immunity.

Calcium signals shape metabolic control of H3K27ac and H3K18la to regulate EGA

The use of assisted reproductive technologies (ART) has enabled the birth of over 9 million babies; but it is associated with increased risks of negative metabolic outcomes in offspring. Yet, the underlying mechanism remains unknown. Calcium (Ca2+) signals, which initiate embryo development at fertilization, are frequently disrupted in human ART. In mice, abnormal Ca2+ signals at fertilization impair embryo development and adult offspring metabolism. Changes in intracellular Ca2+ drive mitochondrial activity and production of metabolites used by the epigenetic machinery. For example, acetyl-CoA (derived mainly from pyruvate) and lactyl-CoA (derived from lactate) are used for writing H3K27ac and H3K18la marks that orchestrate initiation of development. Using both a genetic mouse model and treatment with ionomycin to raise intracellular Ca2+ of wild-type fertilized eggs, we found that excess Ca2+ at fertilization changes metabolic substrate availability, causing epigenetic changes that impact embryo development and offspring health. Specifically, increased Ca2+ exposure at fertilization led to increased H3K27ac levels and decreased H3K18la levels at the 1-cell (1C) stage, that persisted until the 2-cell (2C) stage. Ultralow input CUT&Tag revealed significant differences in H3K27ac and H3K18la genomic profiles between control and ionomycin groups. In addition, increased Ca2+ exposure resulted in a marked reduction in global transcription at the 1C stage that persisted through the 2C stage due to diminished activity of RNA polymerase I. Excess Ca2+ following fertilization increased pyruvate dehydrogenase activity (enzyme that converts pyruvate to acetyl-CoA) and decreased total lactate levels. Provision of exogenous lactyl-CoA before ionomycin treatment restored H3K18la levels at the 1C and 2C stages and rescued global transcription to control levels. Our findings demonstrate conclusively that Ca2+ dynamics drive metabolic regulation of epigenetic reprogramming at fertilization and alter EGA.

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.

Enhancer reprogramming: critical roles in cancer and promising therapeutic strategies

Transcriptional dysregulation is a hallmark of cancer initiation and progression, driven by genetic and epigenetic alterations. Enhancer reprogramming has emerged as a pivotal driver of carcinogenesis, with cancer cells often relying on aberrant transcriptional programs. The advent of high-throughput sequencing technologies has provided critical insights into enhancer reprogramming events and their role in malignancy. While targeting enhancers presents a promising therapeutic strategy, significant challenges remain. These include the off-target effects of enhancer-targeting technologies, the complexity and redundancy of enhancer networks, and the dynamic nature of enhancer reprogramming, which may contribute to therapeutic resistance. This review comprehensively encapsulates the structural attributes of enhancers, delineates the mechanisms underlying their dysregulation in malignant transformation, and evaluates the therapeutic opportunities and limitations associated with targeting enhancers in cancer.

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.

Unlocking the multifaceted molecular functions and diverse disease implications of lactylation

In recent years, a significant breakthrough has emerged in biology, the identification of lactylation, a novel post-translational process. This intriguing modification is not limited to a specific class of proteins but occurs across a diverse range, including histones, signalling molecules, enzymes, and substrates. It can exert a broad regulatory role in various diseases, ranging from developmental anomalies and neurodegenerative disorders to inflammation and cancer. Thus, it presents exciting opportunities for exploring innovative treatment approaches. As a result, there has been a recent surge of research interest, leading to a deeper understanding of the molecular mechanisms and regulatory functions underlying lactylation within physiological and pathological processes. Here, we review the detection and molecular mechanisms of lactylation, from biological functions to disease effects, providing a systematic overview of the mechanisms and functions of this post-translational modification.

The lactate metabolism and protein lactylation in epilepsy

Protein lactylation is a new form of post-translational modification that has recently been proposed. Lactoyl groups, derived mainly from the glycolytic product lactate, have been linked to protein lactylation in brain tissue, which has been shown to correlate with increased neuronal excitability. Ischemic stroke may promote neuronal glycolysis, leading to lactate accumulation in brain tissue. This accumulation of lactate accumulation may heighten neuronal excitability by upregulating protein lactylation levels, potentially triggering post-stroke epilepsy. Although current clinical treatments for seizures have advanced significantly, approximately 30% of patients with epilepsy remain unresponsive to medication, and the prevalence of epilepsy continues to rise. This study explores the mechanisms of epilepsy-associated neuronal death mediated by lactate metabolism and protein lactylation. This study also examines the potential for histone deacetylase inhibitors to alleviate seizures by modifying lactylation levels, thereby offering fresh perspectives for future research into the pathogenesis and clinical treatment of epilepsy.

Histone lactylation-driven B7-H3 expression promotes tumor immune evasion

Rationale: Tumor cells possess sophisticated strategies to circumvent immune detection, including the modulation of endogenous immune checkpoints, particularly those within the B7 family. Elucidating the mechanisms that govern the induction of B7 family molecules is crucial for the advancement of immunotherapy. Lysine lactylation (Kla), a newly identified epigenetic modification, is suggested may play a role in reshaping the tumor microenvironment and facilitating immune evasion. Methods: We analyzed the glycolysis pathway's enrichment in patients with immune-evading tumors and assessed the impact of lactate treatment on the antitumor immunity of CD8+ T cells in the tumor microenvironment. We interrupted glycolysis using lactate dehydrogenase A (LDHA) knockdown and sodium oxamate, and evaluated its effects on CD8+ T cell cytotoxicity. Additionally, we investigated the correlation between B7-H3 expression and the glycolysis pathway, and explored the molecular mechanisms underlying lactate-induced B7-H3 expression. Results: Our findings revealed that the glycolysis pathway was highly enriched in immune-evading tumors. Lactate treatment inhibited the antitumor immunity of CD8+ T cells, whereas interruption of glycolysis via LDHA knockdown or treatment with sodium oxamate augmented the cytotoxicity of CD8+ T cells, effectively counteracting tumor immune evasion. B7-H3 expression was found to be closely linked with the glycolysis pathway. Mechanistically, lactate-upregulated H3K18la directly bound to the B7-H3 promoter in conjunction with the transcription factor Creb1 and its co-activator Ep300, leading to increased B7-H3 expression and contributing to tumor progression by compromising the proportion and cytotoxicity of tumor-infiltrating CD8+ T cells. In mouse tumor bearing models, inhibiting glycolysis and B7-H3 expression suppressed tumor cell growth, activated tumor-infiltrating CD8+ T cells, and demonstrated potent anti-tumor efficacy. Furthermore, this approach enhanced the efficacy of anti-PD-1 treatment. Conclusions: This study uncovers a novel mechanism by which lactate modulates the immune microenvironment through the glycolysis pathway and B7-H3 expression, providing new avenues for lactate metabolism-targeted tumor immunotherapy.

Insight into the roles of lactylation in macrophages: functions and clinical implications

Lactylation, a post-translational modification, has been linked to gene transcription regulation through epigenetic modulation in various pathophysiological processes. The lactylation regulatory proteins, known as writers, erasers, and readers, govern their dynamics by adding, removing, and recognizing lactyl groups on proteins. Macrophages, as cells of the immune system, maintain homeostasis, responding dynamically to diverse internal and external stimuli. Emerging researches unveil that lactylation, through inducing macrophage activation and polarization, affects their functionality in pathological conditions such as inflammation, tumor microenvironment, and fibrosis. Evidence progressively indicates that lactate-driven alterations in lactylation levels within macrophages can influence the pathogenesis of numerous diseases. This review aims to systematically summarize the research progress of lactylation in macrophages, explore its functions and mechanisms by which lactylation contributes to the pathology of different disease phenotypes, and propose future research directions along with potential diagnostic and therapeutic strategies.

Targeting KRAS: from metabolic regulation to cancer treatment

The Kirsten rat sarcoma viral oncogene homolog (KRAS) protein plays a key pathogenic role in oncogenesis, cancer progression, and metastasis. Numerous studies have explored the role of metabolic alterations in KRAS-driven cancers, providing a scientific rationale for targeting metabolism in cancer treatment. The development of KRAS-specific inhibitors has also garnered considerable attention, partly due to the challenge of acquired treatment resistance. Here, we review the metabolic reprogramming of glucose, glutamine, and lipids regulated by oncogenic KRAS, with an emphasis on recent insights into the relationship between changes in metabolic mechanisms driven by KRAS mutant and related advances in targeted therapy. We also focus on advances in KRAS inhibitor discovery and related treatment strategies in colorectal, pancreatic, and non-small cell lung cancer, including current clinical trials. Therefore, this review provides an overview of the current understanding of metabolic mechanisms associated with KRAS mutation and related therapeutic strategies, aiming to facilitate the understanding of current challenges in KRAS-driven cancer and to support the investigation of therapeutic strategies.

Blastocyst-Derived Lactate as a Key Facilitator of Implantation

The blastocyst develops a unique metabolism that facilitates the creation of a specialized microenvironment at the site of implantation characterized by high levels of lactate and reduced pH. While historically perceived as a metabolic waste product, lactate serves as a signaling molecule which facilitates the invasion of surrounding tissues by cancers and promotes blood vessel formation during wound healing. However, the role of lactate in reproduction, particularly at the implantation site, is still being considered. Here, we detail the biological significance of the microenvironment created by the blastocyst at implantation, exploring the origin and significance of blastocyst-derived lactate, its functional role at the implantation site and how understanding this mediator of the maternal-fetal dialogue may help to improve implantation in assisted reproduction.

Lactylation in health and disease: physiological or pathological?

Lactate is an indispensable substance in various cellular physiological functions and plays regulatory roles in different aspects of energy metabolism and signal transduction. Lactylation (Kla), a key pathway through which lactate exerts its functions, has been identified as a novel posttranslational modification (PTM). Research indicates that Kla is an essential balancing mechanism in a variety of organisms and is involved in many key cellular biological processes through different pathways. Kla is closely related to disease development and represents a potential and important new drug target. In line with existing reports, we searched for newly discovered Kla sites on histone and nonhistone proteins; reviewed the regulatory mechanisms of Kla (particularly focusing on the enzymes directly involved in the reversible regulation of Kla, including "writers" (modifying enzymes), "readers" (modification-binding enzymes), and "erasers" (demodifying enzymes); and summarized the crosstalk between different PTMs to help researchers better understand the widespread distribution of Kla and its diverse functions. Furthermore, considering the "double-edged sword" role of Kla in both physiological and pathological contexts, this review highlights the "beneficial" biological functions of Kla in physiological states (energy metabolism, inflammatory responses, cell fate determination, development, etc.) and its "detrimental" pathogenic or inducive effects on pathological processes, particularly malignant tumors and complex nontumor diseases. We also clarify the molecular mechanisms of Kla in health and disease, and discuss its feasibility as a therapeutic target. Finally, we describe the detection technologies for Kla and their potential applications in diagnosis and clinical settings, aiming to provide new insights for the treatment of various diseases and to accelerate translation from laboratory research to clinical practice.

Lactate and lactylation in gastrointestinal cancer: Current progress and perspectives (Review)

Gastrointestinal (GI) cancers, which have notable incidence and mortality, are impacted by metabolic reprogramming, especially the increased production and accumulation of lactate. Lactylation, a post‑translational modification driven by lactate, is a crucial regulator of gene expression and cellular function in GI cancer. The present review aimed to examine advancements in understanding lactate and lactylation in GI cancer. The mechanisms of lactate production, its influence on the tumor microenvironment and the clinical implications of lactate levels as potential biomarkers were explored. Furthermore, lactylation was investigated, including its biochemical foundation, primary targets and functional outcomes. The present review underscored potential therapeutic strategies targeting lactate metabolism and lactylation. Challenges and future directions emphasize the potential of lactate and lactylation as innovative therapeutic targets in GI cancer to improve clinical outcomes.

LDHA-induced histone lactylation mediates the development of osteoarthritis through regulating the transcription activity of TPI1 gene

Osteoarthritis (OA) is a worldwide joint disease, leading to the physical pain, stiffness, and even disability. Lactate dehydrogenase A (LDHA) is known as a lactylation mediator that can regulate histone lactylation of its target genes. However, the role of LDHA-mediated histone H3 lysine 18 lactylation (H3K18la) in OA progression is yet to be clarified. Our study aims at revealing the role and mechanism of LDHA-mediated histone lactylation in the glycolysis of chondrocytes. In this study, we determined at first that the H3K18la level was enhanced in OA. Energy metabolism such as glycolysis is often altered in OA progress. Therefore, we further explored the mechanism mediating glycolysis and thus promoting OA progress. Moreover, glycolysis was enhanced in LPS-induced OA cell model, as evidenced by the increased glucose consumption and lactate production. Furthermore, we silenced LDHA for loss-of-function assays. The results showed that knockdown of LDHA suppressed glycolysis of LPS-induced chondrocytes. In vivo animal study demonstrated that knockout of LDHA recovered cartilage injury of OA mice. Mechanistically, we uncovered that LDHA-mediated H3K18la in TPI1 promoter enhanced the transcription activity of TPI1. Mutation of K69 site was found to ameliorate LPS-induced glycolysis in OA cell model. In conclusion, our study reveals the role of LDHA-mediated H3K18la of TPI1 promoter in OA progress.

Cut&tag: a powerful epigenetic tool for chromatin profiling

Analysis of transcription factors and chromatin modifications at the genome-wide level provides insights into gene regulatory processes, such as transcription, cell differentiation and cellular response. Chromatin immunoprecipitation is the most popular and powerful approach for mapping chromatin, and other enzyme-tethering techniques have recently become available for living cells. Among these, Cleavage Under Targets and Tagmentation (CUT&Tag) is a relatively novel chromatin profiling method that has rapidly gained popularity in the field of epigenetics since 2019. It has also been widely adapted to map chromatin modifications and TFs in different species, illustrating the association of these chromatin epitopes with various physiological and pathological processes. Scalable single-cell CUT&Tag can be combined with distinct platforms to distinguish cellular identity, epigenetic features and even spatial chromatin profiling. In addition, CUT&Tag has been developed as a strategy for joint profiling of the epigenome, transcriptome or proteome on the same sample. In this review, we will mainly consolidate the applications of CUT&Tag and its derivatives on different platforms, give a detailed explanation of the pros and cons of this technique as well as the potential development trends and applications in the future.

Adipose tissue retains an epigenetic memory of obesity after weight loss

Reducing body weight to improve metabolic health and related comorbidities is a primary goal in treating obesity1,2. However, maintaining weight loss is a considerable challenge, especially as the body seems to retain an obesogenic memory that defends against body weight changes3,4. Overcoming this barrier for long-term treatment success is difficult because the molecular mechanisms underpinning this phenomenon remain largely unknown. Here, by using single-nucleus RNA sequencing, we show that both human and mouse adipose tissues retain cellular transcriptional changes after appreciable weight loss. Furthermore, we find persistent obesity-induced alterations in the epigenome of mouse adipocytes that negatively affect their function and response to metabolic stimuli. Mice carrying this obesogenic memory show accelerated rebound weight gain, and the epigenetic memory can explain future transcriptional deregulation in adipocytes in response to further high-fat diet feeding. In summary, our findings indicate the existence of an obesogenic memory, largely on the basis of stable epigenetic changes, in mouse adipocytes and probably other cell types. These changes seem to prime cells for pathological responses in an obesogenic environment, contributing to the problematic 'yo-yo' effect often seen with dieting. Targeting these changes in the future could improve long-term weight management and health outcomes.

Lactate and lysine lactylation of histone regulate transcription in cancer

Histone lysine modifications were well-established epigenetic markers, with many types identified and extensively studied. The discovery of histone lysine lactylation had revealed a new form of epigenetic modification. The intensification of this modification was associated with glycolysis and elevated intracellular lactate levels, both of which were closely linked to cellular metabolism. Histone lactylation plays a crucial role in multiple cellular homeostasis, including immune regulation and cancer progression, thereby significantly influencing cell fate. Lactylation can modify both histone and non-histone proteins. This paper provided a comprehensive review of the typical epigenetic effects and lactylation on classical transcription-related lysine sites and summarized the known enzymes involved in histone lactylation and delactylation. Additionally, some discoveries of histone lactylation in tumor biology were also discussed, and some prospects for this field were put forward.

Lactylation of Hdac1 regulated by Ldh prevents the pluripotent-to-2C state conversion

BACKGROUND

Cellular metabolism regulates the pluripotency of embryonic stem cells (ESCs). Yet, how metabolism regulates the transition among different pluripotent states remains elusive. It has been shown that protein lactylation, which uses lactate, a metabolic product of glycolysis, as a substrate, plays a critical role in various biological events. Here we focused on that glycolysis regulates the conversion between ESCs and 2-cell-like cells (2CLCs) through protein lactylation.

METHODS

RNA-seq revealed the activation of 2-cell (2C) genes by suppression of Ldh. Stable isotope labeling by amino acids in cell culture (SILAC) coupled with lactylated peptide enrichment and quantitative mass spectrometric analysis was carried out to investigate the mechanism how protein lactylation regulates the pluripotent-to-2C transition. And we focused on Hdac1. Lactylation of Hdac1 required for silencing 2C genes was proved by quantitative reverse-transcription PCR (qRT-PCR), immunofluorescence (IF), Western blot and chimeric embryos. Chromatin immunoprecipitation coupled with sequencing (ChIP-seq) and in vitro deacetylation assay confirmed lactylation of Hdac1 promoting its binding at 2C genes and enhancing its deacetylase activity, thereby facilitating the removal of H3K27ac and the silencing of 2C genes.

RESULTS

We found that inhibition or depletion of Ldha, the enzyme converting pyruvate to lactate, leads to the activation of 2C genes, as well as reduced global lactylation in ESCs. To investigate the mechanism how protein lactylation regulates the pluripotent-to-2C transition, quantitative lactylome analysis was performed, and 1716 lactylated proteins were identified. We then focused on Hdac1, a histone deacetylase involved in the silencing of 2C genes. Lactylation of Hdac1 promotes its binding at 2C genes and enhances its deacetylase activity, thus facilitating the removal of H3K27ac and the silencing of 2C genes.

CONCLUSIONS

In summary, our study reveals a mechanistic link between cellular metabolism and pluripotency regulation through protein lactylation. Our research is the first time to reveal that quantitative lactylome analysis in mouse ESCs. We found that lactylated Hdac1 promotes its binding at 2C genes and enhances its deacetylase activity, thus facilitating the removal of H3K27ac and the silencing of 2C genes.

Lactate-mediated lactylation in human health and diseases: Progress and remaining challenges

BACKGROUND

Lactate was once considered as metabolic waste for a long time. In 2019, Professor Zhao Yingming's team from the University of Chicago found that lactate could also be used as a substrate to induce histone lactylation and regulate gene expression. Since then, researchers have discovered that lactate-mediated lactylation play important regulatory roles in various physiological and pathological processes.

AIM OF REVIEW

In this review, we aim to discuss the roles and mechanisms of lactylation in human health and diseases, as well as the effects of lactylation on proteins and metabolic modulators targeting lactylation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this work, we emphasize the crucial regulatory roles of lactylation in the development of numerous physiological and pathological processes. Of relevance, we discuss the current issues and challenges pertaining to lactylation. This review provides directions and a theoretical basis for future research and clinical translation of lactylation.

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.

PYCR1 promotes liver cancer cell growth and metastasis by regulating IRS1 expression through lactylation modification

BACKGROUND

Liver cancer (LC) is among the deadliest cancers worldwide, with existing treatments showing limited efficacy. This study aimed to elucidate the role and underlying mechanisms of pyrroline-5-carboxylate reductase 1 (PYCR1) as a potential therapeutic target in LC.

METHODS

Immunohistochemistry and Western blot were used to analyse the expression of PYCR1 in LC cells and tissues. EdU assays, colony-forming assays, scratch wound healing assays, Transwell assays, nude mouse xenograft models and nude mouse lung metastasis models were used to detect the growth and metastasis abilities of LC cells. Transcriptome sequencing was used to search for downstream target genes regulated by PYCR1, and metabolomics was used to identify the downstream metabolites regulated by PYCR1. ChIP assays were used to analyse the enrichment of H3K18 lactylation in the IRS1 promoter region.

RESULTS

We found that the expression of PYCR1 was significantly increased in HCC and that this high expression was associated with poor prognosis in HCC patients. Knockout or inhibition of PYCR1 inhibited HCC cell proliferation, migration and invasion both in vivo and in vitro. In addition, we revealed that knocking out or inhibiting PYCR1 could inhibit glycolysis in HCC cells and reduce H3K18 lactylation of the IRS1 histone, thereby inhibiting IRS1 expression.

CONCLUSIONS

Our findings identify PYCR1 as a pivotal regulator of LC progression that influences tumour cell metabolism and gene expression. By demonstrating the potential of targeting PYCR1 to inhibit LC cell proliferation and metastasis, this study identified PYCR1 as a promising therapeutic target for LC.

HIGHLIGHTS

Pyrroline-5-carboxylate reductase 1 (PYCR1) promotes the proliferation and metastasis of liver cancer (LC) cells. The expression of PYCR1 in LC is regulated by DNA methylation. Knocking down or inhibiting PYCR1 inhibits glycolysis as well as the PI3K/AKT/mTOR and MAPK/ERK pathways in LC cells. PYCR1 regulates the transcriptional activity of IRS1 by affecting H3K18 lactylation in its promoter region.

Cpt1a Drives primed-to-naïve pluripotency transition through lipid remodeling

Metabolism has been implicated in cell fate determination, particularly through epigenetic modifications. Similarly, lipid remodeling also plays a role in regulating cell fate. Here, we present comprehensive lipidomics analysis during BMP4-driven primed to naive pluripotency transition or BiPNT and demonstrate that lipid remodeling plays an essential role. We further identify Cpt1a as a rate-limiting factor in BiPNT, driving lipid remodeling and metabolic reprogramming while simultaneously increasing intracellular acetyl-CoA levels and enhancing H3K27ac at chromatin open sites. Perturbation of BiPNT by histone acetylation inhibitors suppresses lipid remodeling and pluripotency transition. Together, our study suggests that lipid remodeling promotes pluripotency transitions and further regulates cell fate decisions, implicating Cpt1a as a critical regulator between primed-naive cell fate control.

Histone lactylation regulates autophagy of hyperplastic scar fibroblasts by inhibiting the transcriptional activity of phosphatase and tensin homologue

Hyperplastic scar (HS) is an overreaction of tissue to skin injury caused by local fibroblast proliferation and excessive collagen production. Histone posttranslational modification patterns are important epigenetic processes that control various biological activities. This study was designed to investigate the effects of histone lactylation on HS and the underlying mechanism. Western blot was used to analyse the lactylation level in HS patients and fibroblasts (HSFs). In vitro experiments, western blot, cell counting kit-8, and immunofluorescence staining were performed to detect the collagen level, cell viability, and autophagy, respectively. The relationship between snai2 (SLUG) and phosphatase and tensin homologue (PTEN) was assessed by RNA immunoprecipitation and dual-luciferase reporter assays. The results showed that the histone lactylation level was upregulated in HS tissues and HSFs. HSFs showed increased collagen production and cell viability, and decreased autophagy. Silencing of lactate dehydrogenase A (LDHA) promoted the transcription of PTEN by inhibiting SLUG, thus promoting autophagy. Knockdown of LDHA inhibited collagen deposition and cell viability, and increased autophagy in HSFs, and the results were reversed after PTEN inhibition. In summary, histone lactylation inhibited the transcription activity of PTEN by promoting SLUG, thereby suppressing autophagy and promoting collagen deposition and cell viability of HSFs, which might provide effective therapeutic strategies in HS.

AST-120 alleviates renal ischemia-reperfusion injury by inhibiting HK2-mediated glycolysis

OBJECTIVE

Renal ischemia/reperfusion injury (IRI) is a major cause of acute kidney injury (AKI), which is associated with high incidence and mortality. AST-120 is an oral carbonaceous adsorbent that can alleviate kidney damage. This study aimed to explore the effects of AST-120 on renal IRI and the molecular mechanism.

METHODS

A renal IRI mouse model was established and administrated AST-120, and differentially expressed genes were screened using RNA sequencing. Renal function and pathology were analyzed in mice. Hypoxia/reoxygenation (H/R) cell model was generated, and glycolysis was evaluated by detecting lactate levels and Seahorse analysis. Histone lactylation was analyzed by western blotting, and its relationship with hexokinase 2 (HK2) was assessed using chromatin immunoprecipitation.

RESULTS

The results showed that HK2 expression was increased after IRI, and AST-120 decreased HK2 expression. Knockout of HK2 attenuated renal IRI and inhibits glycolysis. AST-120 inhibited renal IRI in the presence of HK2 rather than HK2 absence. In proximal tubular cells, knockdown of HK2 suppressed glycolysis and H3K18 lactylation caused by H/R. H3K18 lactylation was enriched in HK2 promoter and upregulated HK2 levels. Rescue experiments revealed that lactate reversed IRI that suppressed by HK2 knockdown.

CONCLUSIONS

In conclusion, AST-120 alleviates renal IRI via suppressing HK2-mediated glycolysis, which suppresses H3K18 lactylation and further reduces HK2 levels. This study proposes a novel mechanism by which AST-120 alleviates IRI.

Lactate-induced lactylation and cardiometabolic diseases: From epigenetic regulation to therapeutics

Cardiometabolic diseases (CMDs) denote a cadre of chronic and devastating cardiovascular anomalies routed from metabolic derangements including obesity, type 2 diabetes mellitus, and hypertension. Recent studies have demonstrated the association between histone lactylation, a unique form of post-translational modification, and pathogenesis of CMDs, apparently through epigenetic mechanisms. Lactylation has been indicated to regulate key aspects of metabolism, inflammation, and cardiovascular function in the realm of CMDs in a cellular and tissue-specific manner. A better understanding of the molecular, cellular and physiological domains of lactylation in the etiology of CMDs is expected to offer new insights into etiopathogenesis, hazardous factor control and therapeutic development for these challenging ailments.

Lactate regulates pathological cardiac hypertrophy via histone lactylation modification

Under the long-term pressure overload stimulation, the heart experiences embryonic gene activation, leading to myocardial hypertrophy and ventricular remodelling, which can ultimately result in the development of heart failure. Identifying effective therapeutic targets is crucial for the prevention and treatment of myocardial hypertrophy. Histone lysine lactylation (HKla) is a novel post-translational modification that connects cellular metabolism with epigenetic regulation. However, the specific role of HKla in pathological cardiac hypertrophy remains unclear. Our study aims to investigate whether HKla modification plays a pathogenic role in the development of cardiac hypertrophy. The results demonstrate significant expression of HKla in cardiomyocytes derived from an animal model of cardiac hypertrophy induced by transverse aortic constriction surgery, and in neonatal mouse cardiomyocytes stimulated by Ang II. Furthermore, research indicates that HKla is influenced by glucose metabolism and lactate generation, exhibiting significant phenotypic variability in response to various environmental stimuli. In vitro experiments reveal that exogenous lactate and glucose can upregulate the expression of HKla and promote cardiac hypertrophy. Conversely, inhibition of lactate production using glycolysis inhibitor (2-DG), LDH inhibitor (oxamate) and LDHA inhibitor (GNE-140) reduces HKla levels and inhibits the development of cardiac hypertrophy. Collectively, these findings establish a pivotal role for H3K18la in pathological cardiac hypertrophy, offering a novel target for the treatment of this condition.

CCL2 signaling promotes skeletal muscle wasting in non-tumor and breast tumor models

Despite advancements in treatment, approximately 25% of patients with breast cancer experience long-term skeletal muscle wasting (SMW), which limits mobility, reduces drug tolerance and adversely impacts survival. By understanding the underlying molecular mechanisms of SMW, we may be able to develop new strategies to alleviate this condition and improve the lives of patients with breast cancer. Chemokines are small soluble factors that regulate homing of immune cells to tissues during inflammation. In breast cancers, overexpression of C-C chemokine ligand 2 (CCL2) correlates with unfavorable prognosis. Elevated levels of CCL2 in peripheral blood indicate possible systemic effects of this chemokine in patients with breast cancer. Here, we investigated the role of CCL2 signaling on SMW in tumor and non-tumor contexts. In vitro, increasing concentrations of CCL2 inhibited myoblast and myotube function through C-C chemokine receptor 2 (CCR2)-dependent mechanisms involving JNK, SMAD3 and AMPK signaling. In healthy mice, delivery of recombinant CCL2 protein promoted SMW in a dose-dependent manner. In vivo knockdown of breast tumor-derived CCL2 partially protected against SMW. Overall, chronic, upregulated CCL2-CCR2 signaling positively regulates SMW, with implications for therapeutic targeting.

Histone lactylation-ROS loop contributes to light exposure-exacerbated neutrophil recruitment in zebrafish

Light serves as a crucial external zeitgeber for maintaining and restoring physiological homeostasis in most organisms. Disrupting of light rhythms often leads to abnormal immune function, characterized by excessive inflammatory responses. However, the underlying regulatory mechanisms behind this phenomenon remain unclear. To address this concern, we use in vivo imaging to establish inflammation models in zebrafish, allowing us to investigate the effects and underlying mechanisms of light disruption on neutrophil recruitment. Our findings reveal that under sustained light conditions (LL), neutrophil recruitment in response to caudal fin injury and otic vesicle inflammation is significantly increased. This is accompanied by elevated levels of histone (H3K18) lactylation and reactive oxygen species (ROS) content. Through ChIP-sequencing and ChIP‒qPCR analysis, we discover that H3K18 lactylation regulates the transcriptional activation of the duox gene, leading to ROS production. In turn, ROS further promote H3K18 lactylation, forming a positive feedback loop. This loop, driven by H3K18 lactylation-ROS, ultimately results in the over recruitment of neutrophils to inflammatory sites in LL conditions. Collectively, our study provides evidence of a mutual loop between histone lactylation and ROS, exacerbating neutrophil recruitment in light disorder conditions, emphasizing the significance of maintaining a proper light-dark cycle to optimize immune function.

Hypoxia promotes histone H3K9 lactylation to enhance LAMC2 transcription in esophageal squamous cell carcinoma

Hypoxia promotes tumorigenesis and lactate accumulation in esophageal squamous cell carcinoma (ESCC). Lactate can induce histone lysine lactylation (Kla, a recently identified histone marks) to regulate transcription. However, the functional consequence of histone Kla under hypoxia in ESCC remains to be explored. Here, we reveal that hypoxia facilitates histone H3K9la to enhance LAMC2 transcription for proliferation of ESCC. We found that global level of Kla was elevated under hypoxia, and thus identified the landscape of histone Kla in ESCC by quantitative proteomics. Furthermore, we show a significant increase of H3K9la level induced by hypoxia. Next, MNase ChIP-seq and RNA-seq analysis suggest that H3K9la is enriched at the promoter of cell junction genes. Finally, we demonstrate that the histone H3K9la facilitates the expression of LAMC2 for ESCC invasion by in vivo and in vitro experiments. Briefly, our study reveals a vital role of histone Kla triggered by hypoxia in cancer.

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.

Metabolic enzymes aldo-2 and pdhb-1 as potential epigenetic regulators during C. elegans embryogenesis

The intersection of metabolic processes and epigenetic regulation during embryogenesis is crucial yet not fully understood. Through a candidate RNAi screen in Caenorhabditis elegans , we identified metabolic enzymes ALDO-2 and PDHB-1 as potential epigenetic regulators. Mild alteration of the chromatin remodeler LET-418 /Mi2 activity rescues embryonic lethality induced by suppressing aldo-2 or pdhb-1 , suggesting a critical role for glucose and pyruvate metabolism in chromatin remodeling during embryogenesis. Given the conservation of central metabolic pathways and chromatin modifiers across species, our findings lay the foundation for future mechanistic investigations into the interplay between epigenetics and metabolism during development and upon disease.

Dux activates metabolism-lactylation-MET network during early iPSC reprogramming with Brg1 as the histone lactylation reader

The process of induced pluripotent stem cells (iPSCs) reprogramming involves several crucial events, including the mesenchymal-epithelial transition (MET), activation of pluripotent genes, metabolic reprogramming, and epigenetic rewiring. Although these events intricately interact and influence each other, the specific element that regulates the reprogramming network remains unclear. Dux, a factor known to promote totipotency during the transition from embryonic stem cells (ESC) to 2C-like ESC (2CLC), has not been extensively studied in the context of iPSC reprogramming. In this study, we demonstrate that the modification of H3K18la induced by Dux overexpression controls the metabolism-H3K18la-MET network, enhancing the efficiency of iPSC reprogramming through a metabolic switch and the recruitment of p300 via its C-terminal domain. Furthermore, our proteomic analysis of H3K18la immunoprecipitation experiment uncovers the specific recruitment of Brg1 during reprogramming, with both H3K18la and Brg1 being enriched on the promoters of genes associated with pluripotency and epithelial junction. In summary, our study has demonstrated the significant role of Dux-induced H3K18la in the early reprogramming process, highlighting its function as a potent trigger. Additionally, our research has revealed, for the first time, the binding of Brg1 to H3K18la, indicating its role as a reader of histone lactylation.

Specific regulation of epigenome landscape by metabolic enzymes and metabolites

Metabolism includes anabolism and catabolism, which play an essential role in many biological processes. Chromatin modifications are post-translational modifications of histones and nucleic acids that play important roles in regulating chromatin-associated processes such as gene transcription. There is a tight connection between metabolism and chromatin modifications. Many metabolic enzymes and metabolites coordinate cellular activities with alterations in nutrient availability by regulating gene expression through epigenetic mechanisms such as DNA methylation and histone modifications. The dysregulation of gene expression by metabolism and epigenetic modifications may lead to diseases such as diabetes and cancer. Recent studies reveal that metabolic enzymes and metabolites specifically regulate chromatin modifications, including modification types, modification residues and chromatin regions. This specific regulation has been implicated in the development of human diseases, yet the underlying mechanisms are only beginning to be uncovered. In this review, we summarise recent studies of the molecular mechanisms underlying the metabolic regulation of histone and DNA modifications and discuss how they contribute to pathogenesis. We also describe recent developments in technologies used to address the key questions in this field. We hope this will inspire further in-depth investigations of the specific regulatory mechanisms involved, and most importantly will shed lights on the development of more effective disease therapies.

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.

Macrophage MCT4 inhibition activates reparative genes and protects from atherosclerosis by histone H3 lysine 18 lactylation

Macrophage activation is a hallmark of atherosclerosis, accompanied by a switch in core metabolism from oxidative phosphorylation to glycolysis. The crosstalk between metabolic rewiring and histone modifications in macrophages is worthy of further investigation. Here, we find that lactate efflux-associated monocarboxylate transporter 4 (MCT4)-mediated histone lactylation is closely related to atherosclerosis. Histone H3 lysine 18 lactylation dependent on MCT4 deficiency activated the transcription of anti-inflammatory genes and tricarboxylic acid cycle genes, resulting in the initiation of local repair and homeostasis. Strikingly, histone lactylation is characteristically involved in the stage-specific local repair process during M1 to M2 transformation, whereas histone methylation and acetylation are not. Gene manipulation and protein hydrolysis-targeted chimerism technology are used to confirm that MCT4 deficiency favors ameliorating atherosclerosis. Therefore, our study shows that macrophage MCT4 deficiency, which links metabolic rewiring and histone modifications, plays a key role in training macrophages to become repair and homeostasis phenotypes.

Novel Insights into Psychosis and Antipsychotic Interventions: From Managing Symptoms to Improving Outcomes

For the past 70 years, the dopamine hypothesis has been the key working model in schizophrenia. This has contributed to the development of numerous inhibitors of dopaminergic signaling and antipsychotic drugs, which led to rapid symptom resolution but only marginal outcome improvement. Over the past decades, there has been limited research on the quantifiable pathological changes in schizophrenia, including premature cellular/neuronal senescence, brain volume loss, the attenuation of gamma oscillations in electroencephalograms, and the oxidation of lipids in the plasma and mitochondrial membranes. We surmise that the aberrant activation of the aryl hydrocarbon receptor by toxins derived from gut microbes or the environment drives premature cellular and neuronal senescence, a hallmark of schizophrenia. Early brain aging promotes secondary changes, including the impairment and loss of mitochondria, gray matter depletion, decreased gamma oscillations, and a compensatory metabolic shift to lactate and lactylation. The aim of this narrative review is twofold: (1) to summarize what is known about premature cellular/neuronal senescence in schizophrenia or schizophrenia-like disorders, and (2) to discuss novel strategies for improving long-term outcomes in severe mental illness with natural senotherapeutics, membrane lipid replacement, mitochondrial transplantation, microbial phenazines, novel antioxidant phenothiazines, inhibitors of glycogen synthase kinase-3 beta, and aryl hydrocarbon receptor antagonists.

Orphan Nuclear Receptor NR4A3 Promotes Vascular Calcification via Histone Lactylation

BACKGROUND

Medial arterial calcification is a chronic systemic vascular disorder distinct from atherosclerosis and is commonly observed in patients with chronic kidney disease, diabetes, and aging individuals. We previously showed that NR4A3 (nuclear receptor subfamily 4 group A member 3), an orphan nuclear receptor, is a key regulator in apo (apolipoprotein) A-IV-induced atherosclerosis progression; however, its role in vascular calcification is poorly understood.

METHODS

We generated NR4A3-/- mice and 2 different types of medial arterial calcification models to investigate the biological roles of NR4A3 in vascular calcification. RNA-seq was performed to determine the transcriptional profile of NR4A3-/- vascular smooth muscle cells under β-glycerophosphate treatment. We integrated Cleavage Under Targets and Tagmentation analysis and RNA-seq data to further investigate the gene regulatory mechanisms of NR4A3 in arterial calcification and target genes regulated by histone lactylation.

RESULTS

NR4A3 expression was upregulated in calcified aortic tissues from chronic kidney disease mice, 1,25(OH)2VitD3 overload-induced mice, and human calcified aorta. NR4A3 deficiency preserved the vascular smooth muscle cell contractile phenotype, inhibited osteoblast differentiation-related gene expression, and reduced calcium deposition in the vasculature. Further, NR4A3 deficiency lowered the glycolytic rate and lactate production during the calcification process and decreased histone lactylation. Mechanistic studies further showed that NR4A3 enhanced glycolysis activity by directly binding to the promoter regions of the 2 glycolysis genes ALDOA and PFKL and driving their transcriptional initiation. Furthermore, histone lactylation promoted medial calcification both in vivo and in vitro. NR4A3 deficiency inhibited the transcription activation and expression of Phospho1 (phosphatase orphan 1). Consistently, pharmacological inhibition of Phospho1 attenuated calcium deposition in NR4A3-overexpressed vascular smooth muscle cells, whereas overexpression of Phospho1 reversed the anticalcific effect of NR4A3 deficiency in vascular smooth muscle cells.

CONCLUSIONS

Taken together, our findings reveal that NR4A3-mediated histone lactylation is a novel metabolome-epigenome signaling cascade mechanism that participates in the pathogenesis of medial arterial calcification.

Single-cell 3D genome structure reveals distinct human pluripotent states

BACKGROUND

Pluripotent states of embryonic stem cells (ESCs) with distinct transcriptional profiles affect ESC differentiative capacity and therapeutic potential. Although single-cell RNA sequencing has revealed additional subpopulations and specific features of naive and primed human pluripotent stem cells (hPSCs), the underlying mechanisms that regulate their specific transcription and that control their pluripotent states remain elusive.

RESULTS

By single-cell analysis of high-resolution, three-dimensional (3D) genomic structure, we herein demonstrate that remodeling of genomic structure is highly associated with the pluripotent states of human ESCs (hESCs). The naive pluripotent state is featured with specialized 3D genomic structures and clear chromatin compartmentalization that is distinct from the primed state. The naive pluripotent state is achieved by remodeling the active euchromatin compartment and reducing chromatin interactions at the nuclear center. This unique genomic organization is linked to enhanced chromatin accessibility on enhancers and elevated expression levels of naive pluripotent genes localized to this region. In contradistinction, the primed state exhibits intermingled genomic organization. Moreover, active euchromatin and primed pluripotent genes are distributed at the nuclear periphery, while repressive heterochromatin is densely concentrated at the nuclear center, reducing chromatin accessibility and the transcription of naive genes.

CONCLUSIONS

Our data provide insights into the chromatin structure of ESCs in their naive and primed states, and we identify specific patterns of modifications in transcription and chromatin structure that might explain the genes that are differentially expressed between naive and primed hESCs. Thus, the inversion or relocation of heterochromatin to euchromatin via compartmentalization is related to the regulation of chromatin accessibility, thereby defining pluripotent states and cellular identity.

Histone lactylation in macrophages is predictive for gene expression changes during ischemia induced-muscle regeneration

OBJECTIVES

We have previously shown that lactate is an essential metabolite for macrophage polarisation during ischemia-induced muscle regeneration. Recent in vitro work has implicated histone lactylation, a direct derivative of lactate, in macrophage polarisation. Here, we explore the in vivo relevance of histone lactylation for macrophage polarisation after muscle injury.

METHODS

To evaluate macrophage dynamics during muscle regeneration, we subjected mice to ischemia-induced muscle damage by ligating the femoral artery. Muscle samples were harvested at 1, 2, 4, and 7 days post injury (dpi). CD45+CD11b+F4/80+CD64+ macrophages were isolated and processed for RNA sequencing, Western Blotting, and CUT&Tag-sequencing to investigate gene expression, histone lactylation levels, and histone lactylation genomic localisation and enrichment, respectively.

RESULTS

We show that, over time, macrophages in the injured muscle undergo extensive gene expression changes, which are similar in nature and in timing to those seen after other types of muscle-injuries. We find that the macrophage histone lactylome is modified between 2 and 4 dpi, which is a crucial window for macrophage polarisation. Absolute histone lactylation levels increase, and, although subtly, the genomic enrichment of H3K18la changes. Overall, we find that histone lactylation is important at both promoter and enhancer elements. Lastly, H3K18la genomic profile changes from 2 to 4 dpi were predictive for gene expression changes later in time, rather than being a reflection of prior gene expression changes.

CONCLUSIONS

Our results suggest that histone lactylation dynamics are functionally important for the function of macrophages during muscle regeneration.