LDHA-mediated metabolic reprogramming promoted cardiomyocyte proliferation by alleviating ROS and inducing M2 macrophage polarization

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.

Multifaceted roles of lactate dehydrogenase in liver cancer (Review)

Hepatocellular carcinoma (HCC) has high morbidity and mortality rates, and metabolic reprogramming of HCC cells supports the proliferation and development of tumor cells. Lactate dehydrogenase (LDH), a key metabolic enzyme, can maintain the rapid proliferative demand of tumor cells by promoting glycolysis and lactate production in HCC cells. In addition, LDH regulates redox homeostasis and influences lipid synthesis and signaling pathways, further promoting tumor invasion and metastasis. In the tumor microenvironment, LDH affects the function of immune cells and stromal cells by regulating the lactate concentration in and promoting the immune escape and angiogenesis of tumor cells. Since elevated levels of LDH are closely associated with tumor load, invasiveness and poor prognosis, LDH also has promising applications in the early diagnosis, treatment and prognostic assessment of HCC. The present study reviewed the roles of LDH in the occurrence, development, diagnosis, prognosis and treatment of HCC and explored its value as an important biomarker and potential therapeutic target, with the aim of providing a comprehensive reference for HCC‑related research and clinical practice.

ALDH2 delays ventricular pressure overload-induced heart failure by promoting cardiomyocyte proliferation in mice

The adult mammalian heart is a terminally differentiated organ in which the majority of cardiomyocytes are in a state of cell cycle arrest, rendering them incapable of effectively proliferating to replace damaged cells. ALDH2, an enzyme known for alleviating oxidative stress, has been demonstrated to play a critical role in cardiac protection. However, whether ALDH2 regulates cardiomyocyte proliferation has not been conclusively established. We found that activation of ALDH2 activity significantly promotes cardiomyocyte proliferation and extends the proliferation window during early postnatal development in neonatal mice. Furthermore, administration of Alda-1 to activate ALDH2 in adult mice subjected to transverse aortic constriction markedly enhanced cardiomyocyte proliferation and delayed the onset of pressure overload-induced heart failure. In summary, our findings identify ALDH2 as a potential target for regulating cardiomyocyte proliferation and offer a novel therapeutic approach for treating heart failure.

The anti-atherosclerosis effect and molecular mechanism of AMPKα1 by polarizing monocytes to an M2 phenotype via cell-intrinsic lysosomal lipolysis

Regulating the differentiation of monocytes into M2 macrophages can promote the regression of Atherosclerosis (AS) plaque. However, the key molecules regulating the differentiation of monocytes to M2 are unknown. In this study, we reported that adenosine-activated protein kinase α1 (AMPKα1) plays an anti-AS role by polarizing monocytes to an M2 phenotype via promoting fatty acid oxidation (FAO). AMPKα1 enhances the decomposition of cholesterol esters by increasing lysosomal acid lipase expression to provide fatty acids for FAO. Furthermore, AMPKα1 can induce lysosomal biogenesis and enhance lipolysis by promoting the transcription factor EB (TFEB) expression and facilitating TFEB nuclear translocation. In conclusion, AMPKα1 enhances the decomposition of cholesterol esters by increasing lysosomal acid lipase expression to produce fatty acids, which may represent a mechanism to promote FAO and inflammatory monocytes differentiation towards M2 phenotype.

Cardiomyocyte proliferation: Advances and insights in macrophage-targeted therapy for myocardial injury

In the mammalian heart, cardiomyocytes undergo a transient window of proliferation that leads to regenerative impairment, limiting cardiomyocyte proliferation and myocardial repair capacity. Cardiac developmental patterns exacerbate the progression of heart disease characterized by myocardial cell loss, ultimately leading to cardiac dysfunction and heart failure. Myocardial infarction causes the death of partial cardiomyocytes, which triggers an immune response to remove debris and restore tissue integrity. Interestingly, when transient myocardial injury triggers irreversible loss of cardiomyocytes, the subsequent macrophages responsible for proliferation and regeneration have a unique immune phenotype that promotes the formation of pre-existing new cardiomyocytes. During mammalian regeneration, mononuclear-derived macrophages and self-renewing resident cardiac macrophages provide multiple cytokines and molecular signals that create a regenerative environment and cellular plasticity capacity in postnatal cardiomyocytes, a pivotal strategy for achieving myocardial repair. Consistent with other human tissues, cardiac macrophages originating from the embryonic endothelium produce a hierarchy of contributions to monocyte recruitment and fate specification. In this review, we discuss the novel functions of macrophages in triggering cardiac regeneration and repair after myocardial infarction and provide recent advances and prospective insights into the phenotypic transformation and heterogeneous features involving cardiac macrophages. In conclusion, macrophages contribute critically to regeneration, repair, and remodeling, and are challenging targets for cardiovascular therapeutic interventions.

Lactate released by lung adenocarcinoma (LUAD) cells promotes M2 macrophage polarization via the GPR132/cAMP/PKA pathway

BACKGROUND

Increasing evidence suggests that lactate is an essential compound in the tumor microenvironment, and especially for macrophage cells. However, the mechanism by which lactate affects macrophages remains unclear.

OBJECTIVE

This study investigated whether and how lactate affects macrophage polarization in lung adenocarcinoma (LUAD).

METHODS

Clinical samples of LUAD and paracancerous tissue were obtained for evaluation of lactate dehydrogenase A (LDHA) expression. LUAD cell lines and THP-1 induced macrophages were used in this study. Quantitative real-time PCR (QPCR), western blotting, and immunohistochemical (IHC) staining were performed to detect gene expression. Flow cytometry and ELISA assays were used to detect the levels of M1 macrophage and M2 macrophage biomarkers.

RESULTS

LDHA was highly expressed in the LUAD tissues. Culture medium supernatants derived from LUAD cells (CM) promoted macrophage M2 polarization, and lactate levels were elevated in the CM. Inhibition of LDHA in LUAD cells decreased lactate levels and suppressed M2 macrophage polarization. Moreover, overexpression of GPR132 in macrophages promoted, while GPR132 knockdown in macrophages suppressed M2 macrophage polarization and cAMP (Cyclic Adenosine 3',5'-Monophosphate)/PKA (Protein Kinase) pathway activation induced by lactate. The effect of GPR132 overexpression was reversed by a PKA inhibitor (H-89).

CONCLUSION

Collectively, our results confirmed that lactate released by LUAD cells promoted M2 macrophage polarization via the GPR132/cAMP/PKA pathway.

A self-assembly enzyme-like hydrogel with ROS scavenging and immunomodulatory capability for microenvironment-responsive wound healing acceleration

On-demand responsive hydrogels are a promising solution for effective wound management as they can adjust their properties in response to changes in the wound environment, allowing them to provide tailored support for the healing process. However, the conventional hydrogels may not fully meet the diverse demands of the intricate healing process. Herein, a novel glycyrrhizic acid (GA) based self-assembly hydrogel coordinated with copper and polyphenol (GCP hydrogel) was developed to exhibit triggered release behavior in response to the microenvironment. The GCP hydrogel coordinated with copper and protocatechuic acid (PA) and self-assembled with GA, also exhibits enzyme-like properties by mimicking the cascade process of superoxide dismutase (SOD) and catalase (CAT), effectively scavenging reactive oxygen species (ROS). Furthermore, the on-demand release of Cu2+ at different stages of the wound healing process can not only enhance the antibacterial ability of methicillin-resistant Staphylococcus aureus (MRSA) but also intelligently promote angiogenesis with outstanding biocompatibility. In addition, the GCP hydrogel effectively modulated the activity of macrophages in response to inflammatory stimuli, exhibiting remarkable anti-inflammatory abilities and promoting tissue regeneration. The multifunctional GCP hydrogel platform has the potential to create a dynamic microenvironment that is conducive to tissue regeneration, making it an ideal candidate for smart wound management.

Lactate metabolism and acute kidney injury

ABSTRACT

Acute kidney injury (AKI) is a common clinically critical syndrome in hospitalized patients with high morbidity and mortality. At present, the mechanism of AKI has not been fully elucidated, and no therapeutic drugs exist. As known, glycolytic product lactate is a key metabolite in physiological and pathological processes. The kidney is an important gluconeogenic organ, where lactate is the primary substrate of renal gluconeogenesis in physiological conditions. During AKI, altered glycolysis and gluconeogenesis in kidneys significantly disturb the lactate metabolic balance, which exert impacts on the severity and prognosis of AKI. Additionally, lactate-derived posttranslational modification, namely lactylation, is novel to AKI as it could regulate gene transcription of metabolic enzymes involved in glycolysis or Warburg effect. Protein lactylation widely exists in human tissues and may severely affect non-histone functions. Moreover, the strategies of intervening lactate metabolic pathways are expected to bring a new dawn for the treatment of AKI. This review focused on renal lactate metabolism, especially in proximal renal tubules after AKI, and updated recent advances of lactylation modification, which may help to explore potential therapeutic targets against AKI.

Molecular gatekeepers of endogenous adult mammalian cardiomyocyte proliferation

Irreversible cardiac fibrosis, cardiomyocyte death and chronic cardiac dysfunction after myocardial infarction pose a substantial global health-care challenge, with no curative treatments available. To regenerate the injured heart, cardiomyocytes must proliferate to replace lost myocardial tissue - a capability that adult mammals have largely forfeited to adapt to the demanding conditions of life. Using various preclinical models, our understanding of cardiomyocyte proliferation has progressed remarkably, leading to the successful reactivation of cell cycle induction in adult animals, with functional recovery after cardiac injury. Central to this success is the targeting of key pathways and structures that drive cardiomyocyte maturation after birth - nucleation and ploidy, sarcomere structure, developmental signalling, chromatin and epigenetic regulation, the microenvironment and metabolic maturation - forming a complex regulatory framework that allows efficient cellular contraction but restricts cardiomyocyte proliferation. In this Review, we explore the molecular pathways underlying these core mechanisms and how their manipulation can reactivate the cell cycle in cardiomyocytes, potentially contributing to cardiac repair.

PKM2 crotonylation reprograms glycolysis in VSMCs, contributing to phenotypic switching

Post-translational modifications (PTMs) of pyruvate kinase M2 (PKM2) play a vital role in regulating its activity and function. Recently, we found PKM2 can undergo crotonylation in vascular smooth muscle cell (VSMC) phenotypic switching. However, the role of PKM2 crotonylation remains unknown. Here, we verify a crucial role of PKM2 crotonylation in VSMC metabolic reprogramming. In PDGF-BB-induced synthetic VSMCs, PKM2 crotonylation was upregulated and promotes its nuclear translocation, thereby facilitating the expression of Glut1 and Ldha. Furthermore, crotonylation facilitated the dimeric formation of PKM2. Then we identified the highly conserved crotonylation site at K305 across different species. The crotonylation of PKM2 was compromised by PKM2 K305 mutation, resulting in the suppression of PKM2 dimeric configuration and nuclear relocation, and ultimately reducing glycolysis rate. Furthermore, PKM2 K305 crotonylation was necessary for VSMC phenotypic switching in vitro and intimal hyperplasia in vivo via infection of PKM2 recombinant adenovirus. In summary, PKM2 K305 crotonylation facilitates VSMC aerobic glycolysis by enhancing PKM2 dimeric form.

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.

Lactate dehydrogenase B noncanonically promotes ferroptosis defense in KRAS-driven lung cancer

Ferroptosis is an oxidative, non-apoptotic cell death frequently inactivated in cancer, but the underlying mechanisms in oncogene-specific tumors remain poorly understood. Here, we discover that lactate dehydrogenase (LDH) B, but not the closely related LDHA, subunits of active LDH with a known function in glycolysis, noncanonically promotes ferroptosis defense in KRAS-driven lung cancer. Using murine models and human-derived tumor cell lines, we show that LDHB silencing impairs glutathione (GSH) levels and sensitizes cancer cells to blockade of either GSH biosynthesis or utilization by unleashing KRAS-specific, ferroptosis-catalyzed metabolic synthetic lethality, culminating in increased glutamine metabolism, oxidative phosphorylation (OXPHOS) and mitochondrial reactive oxygen species (mitoROS). We further show that LDHB suppression upregulates STAT1, a negative regulator of SLC7A11, thereby reducing SLC7A11-dependent GSH metabolism. Our study uncovers a previously undefined mechanism of ferroptosis resistance involving LDH isoenzymes and provides a novel rationale for exploiting oncogene-specific ferroptosis susceptibility to treat KRAS-driven lung cancer.

TNF-α disrupts the malate-aspartate shuttle, driving metabolic rewiring in iPSC-derived enteric neural lineages from Parkinson's Disease patients

Gastrointestinal (GI) dysfunction emerges years before motor symptoms in Parkinson's disease (PD), implicating the enteric nervous system (ENS) in early disease progression. However, the mechanisms linking the PD hallmark protein, α-synuclein (α-syn), to ENS dysfunction - and whether these mechanisms are influenced by inflammation - remains elusive. Using iPSC-derived enteric neural lineages from patients with α-syn triplications, we reveal that TNF-α increases mitochondrial-α-syn interactions, disrupts the malate-aspartate shuttle, and forces a metabolic shift toward glutamine oxidation. These alterations drive mitochondrial dysfunction, characterizing metabolic impairment under cytokine stress. Interestingly, targeting glutamate metabolism with Chicago Sky Blue 6B restores mitochondrial function, reversing TNF-α-driven metabolic disruption. Our findings position the ENS as a central player in PD pathogenesis, establishing a direct link between cytokines, α-syn accumulation, metabolic stress and mitochondrial dysfunction. By uncovering a previously unrecognized metabolic vulnerability in the ENS, we highlight its potential as a therapeutic target for early PD intervention.

Extracellular Vesicles in the Mesenchymal Stem Cell/Macrophage Axis: Potential Targets for Inflammatory Treatment

Mesenchymal stem cells (MSCs) have been widely used for the treatment of autoimmune and inflammatory diseases due to their pluripotent differentiation potential and immunomodulatory function. Macrophage (Mφ) polarization also acts an essential and central role in regulating inflammation, basically the dynamic balance of pro-inflammatory M1-like (M1φ) and anti-inflammatory M2-like macrophages (M2φ), affecting the occurrence and progression of inflammatory diseases. Since a pivotal molecular crosstalk between MSCs and Mφ has been elucidated using in vitro and in vivo preclinical studies, we presume that the mesenchymal stem cell/macrophages axis (MSC/Mφ axis) acts an important role in pathophysiological mechanisms of inflammatory diseases and should be the potential therapeutic target. However, the crucial effects of EVs as intercellular communicators and therapeutic agents in the MSC/Mφ axis remains explorable. Therefore, this review elaborated on the mechanisms of EVs mediating the MSC/Mφ axis regulating inflammation in-depth, hoping to provide more references for related research in the future.

A novel tumor-associated macrophage risk signature predicts prognosis and immunotherapy response in lung adenocarcinoma

OBJECTIVE

To systematically characterize tumor-associated macrophage (TAM) subsets in lung adenocarcinoma (LUAD) and establish a TAM-based prognostic risk signature for LUAD patients.

METHODS

Single-cell RNA sequencing (scRNA-seq) and bulk transcriptomic data were integrated to identify TAM subsets linked to LUAD prognosis. Prognostic genes were screened using univariate Cox regression, refined via Least Absolute Shrinkage and Selection Operator (LASSO) regression, and used to construct a 10-gene risk signature. The signature's performance was validated in independent cohorts through receiver operating characteristic curves, Kaplan-Meier survival analysis, and a nomogram. Its predictive ability for immune checkpoint inhibitor (ICI) therapy response was assessed in the IMvigor210 and GSE78220 datasets.

RESULTS

Six distinct TAM subpopulations were identified, with two subsets significantly correlated with poor prognosis. The 10-gene risk signature, derived from TAM-related genes, demonstrated strong prognostic performance in both training and validation cohorts. High-risk patients exhibited markedly worse overall survival compared to low-risk patients. Additionally, the signature effectively stratified patients based on their response to anti-PD-L1 therapy, with high-risk patients exhibiting reduced clinical benefit. A nomogram combining the risk signature with clinicopathological parameters further enhanced survival prediction accuracy, supporting its clinical applicability.

CONCLUSION

This study established a novel TAM-based prognostic risk signature with robust predictive power for both survival outcomes and immunotherapy response in LUAD. These findings enhance our understanding of TAMs' clinical significance and provide a foundation for personalized immunotherapy strategies in LUAD.

Metabolic and transcriptomic insights into temperature controlled hypothermic preservation of human donor hearts

BACKGROUND

Heart transplantation (HT) is the gold standard for end-stage heart disease. Donor heart preservation is an important factor that influences post-transplant success. Recently, temperature-controlled storage has demonstrated reduced primary graft dysfunction compared to standard cold storage though mechanisms are poorly understood. We hypothesized that alterations in gene expression and metabolomics offer insight into improved outcomes observed with temperature-controlled storage.

METHODS

We conducted a comprehensive study to investigate the metabolic and transcriptomic responses of donor hearts preserved for 6 hours using a temperature-controlled hypothermic preservation (TCHP) system compared to conventional static cold storage (SCS). Metabolic assessments were carried out using high-resolution 1H and 31P nuclear magnetic resonance (NMR), and liquid chromatography/mass spectrometry (LC-MS) analysis on tissues obtained from various cardiac regions. Lactate, alanine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), nicotinamide adenine dinucleotide (NAD), reduced nicotinamide adenine dinucleotide (NADH), phosphocreatine, and inorganic phosphate were measured, and metabolite ratios were calculated. Transcriptomic profiling was conducted using high throughput RNA sequencing followed by bioinformatic analysis to explore gene expression changes associated with different preservation methods.

RESULTS

Metabolic analyses revealed largely similar profiles between hearts preserved with TCHP and SCS. Energy metabolite ratios were comparable between preservation methods. Transcriptomic analysis unveiled a high correlation between preservation methods but also showed differential gene expression in energy metabolism and inflammation/immune-related pathways.

CONCLUSIONS

Our study demonstrates that TCHP maintains similar high-energy phosphate reserves to SCS but leads to alterations in gene expression of several metabolic and immunomodulatory pathways. These findings may offer important insight into reduced primary graft dysfunction observed in TCHP- hearts.

Cathepsin K inhibition promotes efficient differentiation of human embryonic stem cells to mature cardiomyocytes by mediating glucolipid metabolism and cellular energy homeostasis

BACKGROUND AND AIM

Generation of functional cardiomyocytes from human pluripotent stem cells (hPSCs) offers promising applications for cardiac regenerative medicine. Proper control of pluripotency and differentiation is vital for generating high-quality cardiomyocytes and repairing damaged myocardium. Cathepsin K, a lysosomal cysteine protease, is a potential target for cardiovascular disease treatment; however, its role in cardiomyocyte differentiation and regeneration is unclear. This study aims to investigate the effects and mechanisms of cathepsin K inhibition on the differentiation of human embryonic stem cell-induced cardiomyocytes (hESC-CMs) and myocardial generation.

METHODS

We cultured H9-hESCs in CDM3 medium to induce myocardial differentiation, adding cathepsin K inhibitor II (1 μM) on days 2, 5 and 8, respectively. Cells were observed and collected 48 h after each treatment. The morphology and contractile clusters of H9-hESCs were tracked with microscopy and video recording. Pluripotency and cardiac markers were assessed at each stage of differentiation. We also examined glucose and lipid metabolism, mitochondrion-related markers, apoptosis and autophagy.

RESULTS

CDM3 medium effectively differentiated high-density H9-hESCs into mature, spontaneously contracting cardiomyocytes. Cathepsin K inhibition accelerates the differentiation of H9-hESCs into cardiac mesoderm and cardiac precursor cells (CPCs) by reducing apoptosis, decreasing glycolysis and fatty acid metabolism at the early and middle stages, and subsequently facilitate the development and differentiation of cardiomyocytes by enhancing glucolipid metabolism and oxidative phosphorylation at the late stage. Meanwhile, cathepsin K inhibition enhanced mitochondrial function and lysosome-related gene transcription during the differentiation process.

CONCLUSION

Our study highlights the potential of cathepsin K inhibition for renewable cardiomyocytes and suggests exploring metabolic pathways and signaling to improve cardiac regeneration and organoid development.

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

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

Micheliolide attenuates sepsis-induced acute lung injury by suppressing mitochondrial oxidative stress and PFKFB3-driven glycolysis

BACKGROUND

Sepsis is a potentially fatal condition with a significant risk of death. Acute lung injury (ALI) is a life-threatening complication of sepsis, and the inflammatory response plays a critical role in sepsis-induced ALI. The protective effects of micheliolide (MCL) against renal fibrosis and leukemia have been demonstrated, but the precise underlying mechanisms remain unclear.

METHODS

In vitro, lipopolysaccharides (LPS) and interferon-gamma (IFN-γ) were used to stimulate RAW264.7 cells and bone marrow-derived macrophages (BMDMs) to investigate the protective effect of MCL on sepsis-induced ALI. Cecal ligation and puncture (CLP) models were constructed in mice to induce ALI in vivo. The expression of inflammatory factors, macrophage polarization markers, and the glycolysis-related enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) were measured in vivo. Mitochondrial function, oxidative stress, and mitochondrial-related proteins were evaluated in vitro.

RESULTS

MCL inhibited CLP-induced ALI, as evidenced by improvements in proinflammatory factor levels, lung wet/dry ratios, and histopathological findings. In vitro, MCL treatment significantly suppressed LPS + IFN-γ-induced M1-type polarization of RAW264.7 cells and BMDMs, as well as the production of inflammatory factors and oxidative stress. Mechanistic experiments revealed that MCL suppresses PFKFB3-driven glycolysis to reduce inflammation and activates the mitochondrial unfolded protein response (UPRmt) to alleviate mitochondrial stress. However, the therapeutic effect of MCL was diminished when PFKFB3 was overexpressed in cells.

CONCLUSION

This study is the first to demonstrate that MCL attenuates sepsis-induced ALI by reducing M1-type macrophage polarization. Its therapeutic effect is closely related to the suppression of oxidative stress and PFKFB3-driven glycolysis.

Unraveling the role of LDHA and VEGFA in oxidative stress: A pathway to therapeutic interventions in cerebral aneurysms

Cerebral aneurysms (CA) are critical conditions often associated with oxidative stress in vascular endothelial cells (VECs). The enzyme lactate dehydrogenase A (LDHA) plays a crucial role in glycolysis and lactate metabolism, processes implicated in the pathogenesis of aneurysms. Understanding these molecular mechanisms can inform the development of novel therapeutic targets. This study investigated the role of lactate metabolism and lactate-related genes, particularly LDHA and vascular endothelial growth factor A (VEGFA) genes, in VECs during oxidative stress. Using the GSE26969 dataset, we identified differential expression of lactate-related genes and performed functional enrichment analysis, revealing significant associations with glycolysis and lactate metabolic pathways. To induce oxidative stress, VECs were treated with H2O2, and the expression of LDHA and VEGFA was analyzed using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) assays. Under oxygen-glucose deprivation/reperfusion (OGD/R) conditions, the effects of LDHA overexpression and VEGFA knockdown on cell viability and apoptosis were evaluated. Immunoprecipitation combined with western blotting was used to detect the lactylation status of LDHA following OGD/R stimulation and treatment with lactic acid (LA) and 2-deoxyglucose (2-DG). Our results indicated that oxidative stress modulates LDHA expression, glucose uptake, and lactate production, suggesting a metabolic shift towards glycolysis. LDHA overexpression improved cell survival and reduced apoptosis, while VEGFA knockdown had the opposite effect. Additionally, 2-DG treatment reduced LDHA lactylation and apoptosis. Our findings demonstrated that LDHA plays a critical role in the oxidative stress response of VECs, highlighting the potential therapeutic value of targeting glycolysis in CA. This study contributes to the understanding of metabolic adaptations in vascular pathologies and suggests new avenues for therapeutic intervention in CA management.

Reprogramming macrophage metabolism following myocardial infarction: A neglected piece of a therapeutic opportunity

Given the global prevalence of myocardial infarction (MI) as the leading cause of mortality, there is an urgent need to devise novel strategies that target reducing infarct size, accelerating cardiac tissue repair, and preventing detrimental left ventricular (LV) remodeling. Macrophages, as a predominant type of innate immune cells, undergo metabolic reprogramming following MI, resulting in alterations in function and phenotype that significantly impact the progression of MI size and LV remodeling. This article aimed to delineate the characteristics of macrophage metabolites during reprogramming in MI and elucidate their targets and functions in cardioprotection. Furthermore, we summarize the currently proposed regulatory mechanisms of macrophage metabolic reprogramming and identify the regulators derived from endogenous products and natural small molecules. Finally, we discussed the challenges of macrophage metabolic reprogramming in the treatment of MI, with the goal of inspiring further fundamental and clinical research into reprogramming macrophage metabolism and validating its potential therapeutic targets for MI.

Human heart assembloids with autologous tissue-resident macrophages recreate physiological immuno-cardiac interactions

Interactions between the developing heart and the embryonic immune system are essential for proper cardiac development and maintaining homeostasis, with disruptions linked to various diseases. While human pluripotent stem cell (hPSC)-derived organoids are valuable models for studying human organ function, they often lack critical tissue-resident immune cells. Here, we introduce an advanced human heart assembloid model, termed hHMA (human heart-macrophage assembloid), which fully integrates autologous cardiac tissue- resident macrophages (MPs) with pre-existing human heart organoids (hHOs). Through multi-omic analyses, we confirmed that these MPs are phenotypically similar to embryonic cardiac tissue-resident MPs and remain viable in the assembloids over time. The inclusion of MPs significantly impacts hHMA development, influencing cardiac cellular composition, boosting cellular communication, remodeling the extracellular matrix, promoting ventricular morphogenesis, and enhancing sarcomeric maturation. Our findings indicate that MPs contribute to homeostasis via efferocytosis, integrate into the cardiomyocyte electrical system, and support catabolic metabolism. To demonstrate the versatility of this model, we developed a platform to study cardiac arrhythmias by chronic exposure to pro-inflammatory factors linked to arrhythmogenesis in clinical settings, successfully replicating key features of inflammasome-mediated atrial fibrillation. Overall, this work introduces a robust platform for examining the role of immune cells in cardiac development, disease mechanisms, and drug discovery, bridging the gap between in vitro models and human physiology. These findings offer insights into cardiogenesis and inflammation-driven heart disease, positioning the hHMA system as an invaluable tool for future cardiovascular research and therapeutic development.

The effect of macrophage-cardiomyocyte interactions on cardiovascular diseases and development of potential drugs

The interaction between macrophages and cardiomyocytes plays an important role not only in maintaining cardiac homeostasis, but also in the development of many cardiovascular diseases (CVDs), such as myocardial infarction (MI) and heart failure (HF). In addition to supporting cardiomyocytes, macrophages and cardiomyocytes have a close and complex relationship. By studying their cross-talk, we can better understand novel mechanisms and target pathogenic mechanisms, and improve the treatment of CVDs. We review macrophage-cardiomyocyte communication through connexin 43 (Cx43)-containing gap junctions (GJs) directly, secreted protein factors indirectly, and discuss the implications of these interactions in cardiac homeostasis and the development of various CVDs, including MI, HF, arrhythmia, cardiac fibrosis and myocarditis. In this section, we review various drugs that work by modulating cytokines or other proteins to reduce inflammation in CVDs. The clinical findings from targeting inflammation in CVDs are also discussed. Additionally, we examine the challenges and opportunities for improving our understanding of macrophage-cardiomyocyte coupling as it relates to pathophysiological disease processes, extending our research scope, and helping identify new molecular targets and improve the effectiveness of existing therapies.

Monomethyl Branched-Chain Fatty Acids Suppress M1 Macrophage Polarization via FABP4/PPAR-γ Signaling Pathway

SCOPE

Monomethyl-branched chain fatty acids (mmBCFAs) are found in a variety of food sources and are of great interest due to their potent antiinflammatory properties. However, most of the current researches have concentrated on the relationship between mmBCFAs and intestinal inflammation, and there is a large gap in the biological mechanisms involved behind their antiinflammatory effects.

METHODS AND RESULTS

The present study examines the role of mmBCFAs in modulating macrophage polarization. The results demonstrate that iso-C16:0 significantly inhibits macrophages M1 proinflammatory polarization through regulating FABP4/PPAR-γ pathway. Proteomics and molecular biology experiments verify that metabolic reprogramming is involved in the inhibition of M1 macrophage, referring to the upregulation of fatty acid oxidation, TCA cycle, and oxidative phosphorylation, as well as downregulation of glycolytic flux.

CONCLUSION

In summary, this study offers a novel perspective on the antiinflammatory effects mediated by mmBCFAs.

Progress of Mitochondrial Function Regulation in Cardiac Regeneration

Heart failure and myocardial infarction, global health concerns, stem from limited cardiac regeneration post-injury. Myocardial infarction, typically caused by coronary artery blockage, leads to cardiac muscle cell damage, progressing to heart failure. Addressing the adult heart's minimal self-repair capability is crucial, highlighting cardiac regeneration research's importance. Studies reveal a metabolic shift from anaerobic glycolysis to oxidative phosphorylation in neonates as a key factor in impaired cardiac regeneration, with mitochondria being central. The heart's high energy demands rely on a robust mitochondrial network, essential for cellular energy, cardiac health, and regenerative capacity. Mitochondria's influence extends to redox balance regulation, signaling molecule interactions, and apoptosis. Changes in mitochondrial morphology and quantity also impact cardiac cell regeneration. This article reviews mitochondria's multifaceted role in cardiac regeneration, particularly in myocardial infarction and heart failure models. Understanding mitochondrial function in cardiac regeneration aims to enhance myocardial infarction and heart failure treatment methods and insights.

Branched-chain amino acids supplementation induces insulin resistance and pro-inflammatory macrophage polarization via INFGR1/JAK1/STAT1 signal pathway

BACKGROUND

Obesity is a global epidemic, and the low-grade chronic inflammation of adipose tissue in obese individuals can lead to insulin resistance and type 2 diabetes. Adipose tissue macrophages (ATMs) are the main source of pro-inflammatory cytokines in adipose tissue, making them an important target for therapy. While branched-chain amino acids (BCAA) have been strongly linked to obesity and type 2 diabetes in humans, the relationship between BCAA catabolism and adipose tissue inflammation is unclear. This study aims to investigate whether disrupted BCAA catabolism influences the function of adipose tissue macrophages and the secretion of pro-inflammatory cytokines in adipose tissue, and to determine the underlying mechanism. This research will help us better understand the role of BCAA catabolism in adipose tissue inflammation, obesity, and type 2 diabetes.

METHODS

In vivo, we examined whether the BCAA catabolism in ATMs was altered in high-fat diet-induced obesity mice, and if BCAA supplementation would influence obesity, glucose tolerance, insulin sensitivity, adipose tissue inflammation and ATMs polarization in mice. In vitro, we isolated ATMs from standard chow and high BCAA-fed group mice, using RNA-sequencing to investigate the potential molecular pathway regulated by BCAA accumulation. Finally, we performed targeted gene silence experiment and used immunoblotting assays to verify our findings.

RESULTS

We found that BCAA catabolic enzymes in ATMs were influenced by high-fat diet induced obesity mice, which caused the accumulation of both BCAA and its downstream BCKA. BCAA supplementation will cause obesity and insulin resistance compared to standard chow (STC) group. And high BCAA diet will induce pro-inflammatory cytokines including Interlukin-1beta (IL-1β), Tumor Necrosis Factor alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) secretion in adipose tissue as well as promoting ATMs M1 polarization (pro-inflammatory phenotype). Transcriptomic analysis revealed that a high BCAA diet would activate IFNGR1/JAK1/STAT1 pathway, and IFNGR1 specific silence can abolish the effect of BCAA supplementation-induced inflammation and ATMs M1 polarization.

CONCLUSIONS

The obesity mice model reveals the catabolism of BCAA was disrupted which will cause the accumulation of BCAA, and high-level BCAA will promote ATMs M1 polarization and increase the pro-inflammatory cytokines in adipose tissue which will cause the insulin resistance in further. Therefore, reducing the circulating level of BCAA can be a therapeutic strategy in obesity and insulin resistance patients.

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.

Lactate and lactylation in cardiovascular diseases: current progress and future perspectives

Cardiovascular diseases (CVDs) are often linked to structural and functional impairments, such as heart defects and circulatory dysfunction, leading to compromised peripheral perfusion and heightened morbidity risks. Metabolic remodeling, particularly in the context of cardiac fibrosis and inflammation, is increasingly recognized as a pivotal factor in the pathogenesis of CVDs. Metabolic syndromes further predispose individuals to these conditions, underscoring the need to elucidate the metabolic underpinnings of CVDs. Lactate, a byproduct of glycolysis, is now recognized as a key molecule that connects cellular metabolism with the regulation of cellular activity. The transport of lactate between different cells is essential for metabolic homeostasis and signal transduction. Disruptions to lactate dynamics are implicated in various CVDs. Furthermore, lactylation, a novel post-translational modification, has been identified in cardiac cells, where it influences protein function and gene expression, thereby playing a significant role in CVD pathogenesis. In this review, we summarized recent advancements in understanding the role of lactate and lactylation in CVDs, offering fresh insights that could guide future research directions and therapeutic interventions. The potential of lactate metabolism and lactylation as innovative therapeutic targets for CVD is a promising avenue for exploration.

GAPDH-Silence Microsphere via Reprogramming Macrophage Metabolism and eradicating Bacteria for Diabetic infection bone regeneration

Macrophage metabolism dysregulation, which is exacerbated by persistent stimulation in infectious and inflammatory diseases, such as diabetic infectious bone defects (DIBD), eventually leads to the failure of bone repair. Here, we have developed an injectable, macrophage-modulated GAPDH-Silence drug delivery system. This microsphere comprises chondroitin sulfate methacrylate (CM) and methacrylated gelatin (GM), while the dimethyl fumarate (DMF)-loaded liposome (D-lip) is encapsulated within the microsphere (CM@GM), named D-lip/CM@GM. Triggered by the over-expressed collagenase in DIBD, the microspheres degrade and release the encapsulated D-lip. D-lip could modulate metabolism by inhibiting GAPDH, which suppresses the over-activation of glycolysis, thus preventing the inflammatory response of macrophages in vitro. While beneficial for macrophages, D-lip/CM@GM is harmful to bacteria. GAPDH, while crucial for glycolysis of staphylococcal species (S. aureus), can be effectively countered by D-lip/CM@GM. We are utilizing existing drugs in innovative ways to target central metabolism for effective eradication of bacteria. In the DIBD model, our results confirmed that the D-lip/CM@GM enhanced bacteria clearance and reprogrammed dysregulated metabolism, thereby significantly improving bone regeneration. In conclusion, this GAPDH-Silence microsphere system may provide a viable strategy to promote diabetic infection bone regeneration.

Dynamics of Redox Metabolism during Complete Metamorphosis of Insects: Insights from the Sunflower Caterpillar Chlosyne lacinia (Lepidoptera)

Complete insect metamorphosis requires substantial metabolic and physiological adjustments. Although oxidative stress has been implicated in metamorphosis, details on redox metabolism during larva-to-pupa and pupa-to-adult remain scarce. This study explores redox metabolism during metamorphosis of a lepidopteran (Chlosyne lacinia), focusing on core metabolism, antioxidant systems and oxidative stress. The larva-to-pupa transition was characterized by increased lactate dehydrogenase and glutathione peroxidase (GPX) activities, coupled with depletion of reduced glutathione (GSH), high disulfide-to-total-glutathione ratio (GSSG/tGSH), and increased lipid peroxidation. As metamorphosis progressed, metabolic enzyme activities, citrate synthase and glucose 6-phosphate dehydrogenase increased, indicating heightened oxidative metabolism associated with adult development. Concurrently, GSH and GPX levels returned to larval levels and GSSG/tGSH reached its most reduced state right before adult emergence. Adult emergence was marked by a further increase in oxidative metabolism, accompanied by redox imbalance and enhanced antioxidant mechanisms. These findings highlight a fluctuation in redox balance throughout metamorphosis, with periods of oxidative eustress followed by compensatory antioxidant responses. This study is the first to identify concurrent changes in metabolism, antioxidants, redox balance and oxidative stress throughout metamorphosis. Our findings extend knowledge on redox metabolism adjustments and highlight redox adaptations and oxidative stress as natural components of complete insect metamorphosis.

Lactate dehydrogenase A (LDHA)-mediated lactate generation promotes pulmonary vascular remodeling in pulmonary hypertension

BACKGROUND

High levels of lactate are positively associated with prognosis and mortality in pulmonary hypertension (PH). Lactate dehydrogenase A (LDHA) is a key enzyme for the production of lactate. This study is undertaken to investigate the role and molecular mechanisms of lactate and LDHA in PH.

METHODS

Lactate levels were measured by a lactate assay kit. LDHA expression and localization were detected by western blot and Immunofluorescence. Proliferation and migration were determined by CCK8, western blot, EdU assay and scratch-wound assay. The right heart catheterization and right heart ultrasound were measured to evaluate cardiopulmonary function.

RESULTS

In vitro, we found that lactate promoted proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) in an LDHA-dependent manner. In vivo, we found that LDHA knockdown reduced lactate overaccumulation in the lungs of mice exposed to hypoxia. Furthermore, LDHA knockdown ameliorated hypoxia-induced vascular remodeling and right ventricular dysfunction. In addition, the activation of Akt signaling by hypoxia was suppressed by LDHA knockdown both in vivo and in vitro. The overexpression of Akt reversed the inhibitory effect of LDHA knockdown on proliferation in PASMCs under hypoxia. Finally, LDHA inhibitor attenuated vascular remodeling and right ventricular dysfunction in Sugen/hypoxia mouse PH model, Monocrotaline (MCT)-induced rat PH model and chronic hypoxia-induced mouse PH model.

CONCLUSIONS

Thus, LDHA-mediated lactate production promotes pulmonary vascular remodeling in PH by activating Akt signaling pathway, suggesting the potential role of LDHA in regulating the metabolic reprogramming and vascular remodeling in PH.

A novel long non-coding RNA linc-93.2 participates in bisphenol induced oxidative stress and macrophage polarization in red common carp (Cyprinus carpio)

Previous studies show that bisphenol A (BPA) and its analogs induce oxidative stress and promote inflammatory response. However, the key molecules in regulating this process remain unclear. Here, we report significant inductive effects of BPA and bisphenol AF (BPAF) on a newly found long non-coding RNA linc-93.2 accompanied by oxidative stress and activation of pro-inflammatory pathways in treated fish and fish primary macrophages. Silencing linc-93.2 in fish primary macrophages in vitro or fish in vivo significantly promotes the expression of anti-oxidative stress-related genes and anti-inflammatory cytokines. This inhibition of pro-inflammatory cytokine expression, showing cell status disruption towards to M2 polarization. Followed by exposure to BPA or BPAF, silencing linc-93.2 in vitro or in vivo significantly attenuates the increased production of reactive oxygen species and malondialdehyde level aroused by bisphenol treatment, possibly owing to the enhancement of total antioxidant capacity observed in cells and tissue after linc-93.2 knockdown. RNA-sequencing further revealed regulation of nuclear factor-kappa b (NF-κB) in linc-93.2's downstream network, combining with our previous observation on the upstream regulation of linc-93.2 via NF-κB, which together suggest a critical role of linc-93.2 in promoting NF-κB positive feedback loop that may be an important molecular event initiating the immunotoxicity of bisphenols.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

The regulatory effect of TiO2 nanotubes loaded with graphene oxide on macrophage polarization in an inflammatory environment

BACKGROUND

Excessive inflammation is a major cause of implant failure. The surface morphology, hydrophilicity, and loading of biomaterials are major properties modulating anti-inflammatory macrophage activation. This paper investigates the regulatory effects of modifying the surface of Titanium dioxide nanotubes (TNTs) with graphene oxide (GO) on the polarization of mouse monocyte macrophages (RAW264.7).

METHODS

TNT was produced by the anodic oxidation of titanium. GO was subsequently electrodeposited on the TNT to obtain a TNT-GO composite. The samples were characterised through scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction. RAW264.7 cells were separately seeded onto the surface of three groups of samples: pure Ti, TNT, and TNT-GO. Under the condition of lipopolysaccharide stimulation, the influence of the sample surfaces on the gene expression profiles was investigated through RNA sequence analysis. In addition, cell spreading was observed through SEM, cell adhesion and proliferation were analysed using the CCK8 assay, and the expression of inflammation-related factors was investigated by ELISA and cellular immunofluorescence staining. The production of reactive oxygen species (ROS) in the RAW264.7 cells on the surface of the three groups was detected via immunofluorescence staining.

RESULTS

The CCK8 results indicated that the adhesion and proliferation of the RAW264.7 cells were reduced on the TNT and TNT-GO surfaces. ELISA results revealed significant differences in the pro-inflammatory factors tumour necrosis factor-α and interleukin-6 secretion among the three groups at 24 h (p < 0.05). The secretion of pro-inflammatory factors significantly reduced and the expression of anti-inflammatory factor IL-10 increased on the TNT and TNT-GO surfaces. The RNA sequencing, ELISA, and cell immunofluorescence staining test results suggested that the inflammatory response of M1 polarization was reduced and the M2 polarization of macrophages was induced on the TNT-GO surface, which may be attributed to the reduction in ROS production.

CONCLUSIONS

Under lipopolysaccharide stimulation, the inflammatory response of the RAW264.7 cells was reduced and the M2 polarization of macrophages was promoted on the TNT-GO surface, which may be caused by the reduced ROS production. Consequently, the designed TNT-GO material is promising for implants owing to its excellent inflammation regulation ability.

Reduction-sensitive polymeric carrier for the targeted delivery of a quinazoline derivative for enhanced generation of reactive oxygen species against cancer

Hepatocellular carcinoma (HCC) is one of the deadliest malignant tumors and the development of effective therapeutics against HCC is urgently needed. A novel quinazoline derivative 04NB-03 (Qd04) has been proved to be highly effective against HCC without obvious toxic side-effects. However, the poor water solubility and low bioavailability in vivo severely limit its clinical application. In addition, Qd04 kills tumor cells by inducing an accumulation of endogenous reactive oxygen species (ROS), which is highly impeded by the overexpression of glutathione (GSH) in tumor cells. Herein, we designed a disulfide cross-linked polyamino acid micelle to deliver Qd04 for HCC therapy. The disulfide linkage not only endowed a tumor-targeted delivery of Qd04 by responding to tumor cell GSH but also depleted GSH to achieve increased levels of ROS generation, which improved the therapeutic efficiency of Qd04. Both in vitro and in vivo results demonstrated that the synthesized nanodrug exerted good anti-hepatoma effects, which provided a potential application for HCC therapy in clinics.

Metabolic Reprogramming: A Byproduct or a Driver of Cardiomyocyte Proliferation?

Defining mechanisms of cardiomyocyte proliferation should guide the understanding of endogenous cardiac regeneration and could lead to novel treatments for diseases such as myocardial infarction. In the neonatal heart, energy metabolic reprogramming (phenotypic alteration of glucose, fatty acid, and amino acid metabolism) parallels cell cycle arrest of cardiomyocytes. The metabolic reprogramming occurring shortly after birth is associated with alterations in blood oxygen levels, metabolic substrate availability, hemodynamic stress, and hormone release. In the adult heart, myocardial infarction causes metabolic reprogramming but these changes cannot stimulate sufficient cardiomyocyte proliferation to replace those lost by the ischemic injury. Some putative pro-proliferative interventions can induce the metabolic reprogramming. Recent data show that altering the metabolic enzymes PKM2 [pyruvate kinase 2], LDHA [lactate dehydrogenase A], PDK4 [pyruvate dehydrogenase kinase 4], SDH [succinate dehydrogenase], CPT1b [carnitine palmitoyl transferase 1b], or HMGCS2 [3-hydroxy-3-methylglutaryl-CoA synthase 2] is sufficient to partially reverse metabolic reprogramming and promotes adult cardiomyocyte proliferation. How metabolic reprogramming regulates cardiomyocyte proliferation is not clearly defined. The possible mechanisms involve biosynthetic pathways from the glycolysis shunts and the epigenetic regulation induced by metabolic intermediates. Metabolic manipulation could represent a new approach to stimulate cardiac regeneration; however, the efficacy of these manipulations requires optimization, and novel molecular targets need to be defined. In this review, we summarize the features, triggers, and molecular regulatory networks responsible for metabolic reprogramming and discuss the current understanding of metabolic reprogramming as a critical determinant of cardiomyocyte proliferation.

The effect of macrophages and their exosomes in ischemic heart disease

Ischemic heart disease (IHD) is a leading cause of disability and death worldwide, with immune regulation playing a crucial role in its pathogenesis. Various immune cells are involved, and as one of the key immune cells residing in the heart, macrophages play an indispensable role in the inflammatory and reparative processes during cardiac ischemia. Exosomes, extracellular vesicles containing lipids, nucleic acids, proteins, and other bioactive molecules, have emerged as important mediators in the regulatory functions of macrophages and hold promise as a novel therapeutic target for IHD. This review summarizes the regulatory mechanisms of different subsets of macrophages and their secreted exosomes during cardiac ischemia over the past five years. It also discusses the current status of clinical research utilizing macrophages and their exosomes, as well as strategies to enhance their therapeutic efficacy through biotechnology. The aim is to provide valuable insights for the treatment of IHD.

A systematic pan-cancer analysis identifies LDHA as a novel predictor for immunological, prognostic, and immunotherapy resistance

Lactate dehydrogenase A (LDHA), a critical enzyme involved in glycolysis, is broadly involved multiple biological functions in human cancers. It is reported that LDHA can impact tumor immune surveillance and induce the transformation of tumor-associated macrophages, highlighting its unnoticed function of LDHA in immune system. However, in human cancers, the role of LDHA in prognosis and immunotherapy hasn't been investigated. In this study, we analyzed the expression pattern and prognostic value of LDHA in pan-cancer and explored its association between tumor microenvironment (TME), immune infiltration subtype, stemness scores, tumor mutation burden (TMB), and immunotherapy resistance. We found that LDHA expression is tumor heterogeneous and that its high expression is associated with poor prognosis in multiple human cancers. In addition, LDHA expression was positively correlated with the presence of mononuclear/macrophage cells, and also promoted the infiltration of a range of immune cells. Genomic alteration of LDHA was common in different types of cancer, while with prognostic value in pan-cancers. Pan-cancer analysis revealed that the significant correlations existed between LDHA expression and tumor microenvironment (including stromal cells and immune cells) as well as stemness scores (DNAss and RNAss) across cancer types. Drug sensitivity analysis also revealed that LDHA was able to predict response to chemotherapy and immunotherapy. Furthermore, it was confirmed that knockdown of LDHA reduced proliferation and migration ability of lung cancer cells. Taken together, LDHA could serve as a prognostic biomarker and a potential immunotherapy marker.

Metal natural product complex Ru-procyanidins with quadruple enzymatic activity combat infections from drug-resistant bacteria

Bacterial infection hampers wound repair by impeding the healing process. Concurrently, inflammation at the wound site triggers the production of reactive oxygen species (ROS), causing oxidative stress and damage to proteins and cells. This can lead to chronic wounds, posing severe risks. Therefore, eliminating bacterial infection and reducing ROS levels are crucial for effective wound healing. Nanozymes, possessing enzyme-like catalytic activity, can convert endogenous substances into highly toxic substances, such as ROS, to combat bacteria and biofilms without inducing drug resistance. However, the current nanozyme model with single enzyme activity falls short of meeting the complex requirements of antimicrobial therapy. Thus, developing nanozymes with multiple enzymatic activities is essential. Herein, we engineered a novel metalloenzyme called Ru-procyanidin nanoparticles (Ru-PC NPs) with diverse enzymatic activities to aid wound healing and combat bacterial infections. Under acidic conditions, due to their glutathione (GSH) depletion and peroxidase (POD)-like activity, Ru-PC NPs combined with H2O2 exhibit excellent antibacterial effects. However, in a neutral environment, the Ru-PC NPs, with catalase (CAT) activity, decompose H2O2 to O2, alleviating hypoxia and ensuring a sufficient oxygen supply. Furthermore, Ru-PC NPs possess exceptional antioxidant capacity through their superior superoxide dismutase (SOD) enzyme activity, effectively scavenging excess ROS and reactive nitrogen species (RNS) in a neutral environment. This maintains the balance of the antioxidant system and prevents inflammation. Ru-PC NPs also promote the polarization of macrophages from M1 to M2, facilitating wound healing. More importantly, Ru-PC NPs show good biosafety with negligible toxicity. In vivo wound infection models have confirmed the efficacy of Ru-PC NPs in inhibiting bacterial infection and promoting wound healing. The focus of this work highlights the quadruple enzymatic activity of Ru-PC NPs and its potential to reduce inflammation and promote bacteria-infected wound healing.

Distinct features of the regenerating heart uncovered through comparative single-cell profiling

Adult humans respond to heart injury by forming a permanent scar, yet other vertebrates are capable of robust and complete cardiac regeneration. Despite progress towards characterizing the mechanisms of cardiac regeneration in fish and amphibians, the large evolutionary gulf between mammals and regenerating vertebrates complicates deciphering which cellular and molecular features truly enable regeneration. To better define these features, we compared cardiac injury responses in zebrafish and medaka, two fish species that share similar heart anatomy and common teleost ancestry but differ in regenerative capability. We used single-cell transcriptional profiling to create a time-resolved comparative cell atlas of injury responses in all major cardiac cell types across both species. With this approach, we identified several key features that distinguish cardiac injury response in the non-regenerating medaka heart. By comparing immune responses to injury, we found altered cell recruitment and a distinct pro-inflammatory gene program in medaka leukocytes, and an absence of the injury-induced interferon response seen in zebrafish. In addition, we found a lack of pro-regenerative signals, including nrg1 and retinoic acid, from medaka endothelial and epicardial cells. Finally, we identified alterations in the myocardial structure in medaka, where they lack primordial layer cardiomyocytes and fail to employ a cardioprotective gene program shared by regenerating vertebrates. Our findings reveal notable variation in injury response across nearly all major cardiac cell types in zebrafish and medaka, demonstrating how evolutionary divergence influences the hidden cellular features underpinning regenerative potential in these seemingly similar vertebrates.

Nicotinamide adenine dinucleotide phosphate oxidase in pancreatic diseases: Mechanisms and future perspectives

Pancreatitis and pancreatic cancer (PC) stand as the most worrisome ailments affecting the pancreas. Researchers have dedicated efforts to unraveling the mechanisms underlying these diseases, yet their true nature continues to elude their grasp. Within this realm, oxidative stress is often believed to play a causal and contributory role in the development of pancreatitis and PC. Excessive accumulation of reactive oxygen species (ROS) can cause oxidative stress, and the key enzyme responsible for inducing ROS production in cells is nicotinamide adenine dinucleotide phosphate hydrogen oxides (NOX). NOX contribute to pancreatic fibrosis and inflammation by generating ROS that injure acinar cells, activate pancreatic stellate cells, and mediate macrophage polarization. Excessive ROS production occurs during malignant transformation and pancreatic carcinogenesis, creating an oxidative microenvironment that can cause abnormal apoptosis, epithelial to mesenchymal transition and genomic instability. Therefore, understanding the role of NOX in pancreatic diseases contributes to a more in-depth exploration of the exact pathogenesis of these diseases. In this review, we aim to summarize the potential roles of NOX and its mechanism in pancreatic disorders, aiming to provide novel insights into understanding the mechanisms underlying these diseases.

TMEM225 Is Essential for Sperm Maturation and Male Fertility by Modifying Protein Distribution of Sperm in Mice

Nonobstructive azoospermia is the leading cause of male infertility. Abnormal levels of transmembrane protein 225 (TMEM225), a testis-specific protein, have been found in patients with nonobstructive azoospermia, suggesting that TMEM225 plays an essential role in male fertility. Here, we generated a Tmem225 KO mouse model to explore the function and mechanism of TMEM225 in male reproduction. Male Tmem225 KO mice were infertile. Surprisingly, Tmem225 deletion did not affect spermatogenesis, but TMEM225-null sperm exhibited abnormalities during epididymal maturation, resulting in reduced sperm motility and an abnormal hairpin-loop configuration. Furthermore, proteomics analyses of cauda sperm revealed that signaling pathways related to mitochondrial function, the glycolytic pathway, and sperm flagellar morphology were abnormal in Tmem225 KO sperm, and spermatozoa lacking TMEM225 exhibited high reactive oxygen species levels, reduced motility, and flagellar folding, leading to typical asthenospermia. These findings suggest that testicular TMEM225 may control the sperm maturation process by regulating the expression of proteins related to mitochondrial function, glycolysis, and sperm flagellar morphology in epididymal spermatozoa.

The characteristics of proliferative cardiomyocytes in mammals

Better understanding of the mechanisms regulating the proliferation of pre-existing cardiomyocyte (CM) should lead to better options for regenerating injured myocardium. The absence of a perfect research model to definitively identify newly formed mammalian CMs is lacking. However, methodologies are being developed to identify and enrich proliferative CMs. These methods take advantages of the different proliferative states of CMs during postnatal development, before and after injury in the neonatal heart. New approaches use CMs labeled in lineage tracing animals or single cell technique-based CM clusters. This review aims to provide a timely update on the characteristics of the proliferative CMs, including their structural, functional, genetic, epigenetic and metabolic characteristics versus non-proliferative CMs. A better understanding of the characteristics of proliferative CMs should lead to the mechanisms for inducing endogenous CMs to self-renew, which is a promising therapeutic strategy to treat cardiac diseases that cause CM death in humans.

The role of glycolytic metabolic pathways in cardiovascular disease and potential therapeutic approaches

Cardiovascular disease (CVD) is a major threat to human health, accounting for 46% of non-communicable disease deaths. Glycolysis is a conserved and rigorous biological process that breaks down glucose into pyruvate, and its primary function is to provide the body with the energy and intermediate products needed for life activities. The non-glycolytic actions of enzymes associated with the glycolytic pathway have long been found to be associated with the development of CVD, typically exemplified by metabolic remodeling in heart failure, which is a condition in which the heart exhibits a rapid adaptive response to hypoxic and hypoxic conditions, occurring early in the course of heart failure. It is mainly characterized by a decrease in oxidative phosphorylation and a rise in the glycolytic pathway, and the rise in glycolysis is considered a hallmark of metabolic remodeling. In addition to this, the glycolytic metabolic pathway is the main source of energy for cardiomyocytes during ischemia-reperfusion. Not only that, the auxiliary pathways of glycolysis, such as the polyol pathway, hexosamine pathway, and pentose phosphate pathway, are also closely related to CVD. Therefore, targeting glycolysis is very attractive for therapeutic intervention in CVD. However, the relationship between glycolytic pathway and CVD is very complex, and some preclinical studies have confirmed that targeting glycolysis does have a certain degree of efficacy, but its specific role in the development of CVD has yet to be explored. This article aims to summarize the current knowledge regarding the glycolytic pathway and its key enzymes (including hexokinase (HK), phosphoglucose isomerase (PGI), phosphofructokinase-1 (PFK1), aldolase (Aldolase), phosphoglycerate metatase (PGAM), enolase (ENO) pyruvate kinase (PKM) lactate dehydrogenase (LDH)) for their role in cardiovascular diseases (e.g., heart failure, myocardial infarction, atherosclerosis) and possible emerging therapeutic targets.

Macrophage-driven cardiac inflammation and healing: insights from homeostasis and myocardial infarction

Early and prompt reperfusion therapy has markedly improved the survival rates among patients enduring myocardial infarction (MI). Nonetheless, the resulting adverse remodeling and the subsequent onset of heart failure remain formidable clinical management challenges and represent a primary cause of disability in MI patients worldwide. Macrophages play a crucial role in immune system regulation and wield a profound influence over the inflammatory repair process following MI, thereby dictating the degree of myocardial injury and the subsequent pathological remodeling. Despite numerous previous biological studies that established the classical polarization model for macrophages, classifying them as either M1 pro-inflammatory or M2 pro-reparative macrophages, this simplistic categorization falls short of meeting the precision medicine standards, hindering the translational advancement of clinical research. Recently, advances in single-cell sequencing technology have facilitated a more profound exploration of macrophage heterogeneity and plasticity, opening avenues for the development of targeted interventions to address macrophage-related factors in the aftermath of MI. In this review, we provide a summary of macrophage origins, tissue distribution, classification, and surface markers. Furthermore, we delve into the multifaceted roles of macrophages in maintaining cardiac homeostasis and regulating inflammation during the post-MI period.

The crosstalk between M1 macrophage polarization and energy metabolism disorder contributes to polystyrene nanoplastics-triggered testicular inflammation

Ubiquitous microplastics have become a threat to animal and human health, due to their potential toxicity, persistent nature and consequent bioaccumulation. Supporting evidence elucidates that polystyrene nanoplastics (PS-NPs) can destroy blood-testis barrier integrity, thus causing testicular hypoplasia and impairment of spermatogenesis. Nevertheless, how PS-NPs modulate macrophage polarization-energy metabolism crosstalk has not been fully investigated in testicular tissue. Here, we observed that polystyrene PS-NPs exposure contributes to severe vacuolization in the seminiferous tubules, accompanied by apoptosis of testicular tissue and infiltration of M1 macrophages. Meanwhile, we found that PS-NPs could trigger the M1 polarization phenotype, which activated ROS-macrophage migration inhibitory factor (MIF)/NF-κB signaling that in turn induced apoptosis of GC2 cells in the GC2-macrophage cell coculture model. Simultaneously, we confirmed that PS-NPs exposure increased 3-phospho-D-glycerate, phosphoenolpyruvate and lactate concentrations, accompanied by decreased pyruvate and adenosine triphosphate (ATP) production, likely due to downregulated pyruvate kinase M2 (PKM2) dimer expression. In conclusion, the mechanism of PS-NPs-induced testicular inflammation can be mediated by promoting the infiltration of M1 macrophages, thereby resulting in an ROS burst and subsequent induction of energy metabolism disorders. The current study will provide new insights into PS-NPs-induced male reproductive toxicity and highlight the context-specific roles of testicular macrophages.

Cardiac macrophages and emerging roles for their metabolism after myocardial infarction

Interest in cardioimmunology has reached new heights as the experimental cardiology field works to tap the unrealized potential of immunotherapy for clinical care. Within this space is the cardiac macrophage, a key modulator of cardiac function in health and disease. After a myocardial infarction, myeloid macrophages both protect and harm the heart. To varying degrees, such outcomes are a function of myeloid ontogeny and heterogeneity, as well as functional cellular plasticity. Diversity is further shaped by the extracellular milieu, which fluctuates considerably after coronary occlusion. Ischemic limitation of nutrients constrains the metabolic potential of immune cells, and accumulating evidence supports a paradigm whereby macrophage metabolism is coupled to divergent inflammatory consequences, although experimental evidence for this in the heart is just emerging. Herein we examine the heterogeneous cardiac macrophage response following ischemic injury, with a focus on integrating putative contributions of immunometabolism and implications for therapeutically relevant cardiac injury versus cardiac repair.

Dynamic changes in macrophage subtypes during lung cancer progression and metastasis at single-cell resolution

Background

Lung cancer remains a major global health challenge. Macrophages (Macs) are one important component of tumor microenvironments (TMEs); however, their prognostic relevance to lung cancer is currently unknown due to the complexity of their phenotypes.

Methods

In the present study, reanalysis and atlas reconstruction of downloaded single-cell RNA sequencing (scRNAseq) data were used to systematically compare the component and transcriptional changes in Mac subtypes across different stages of lung cancer.

Results

We found that with the progression of lung cancer, the proportion of alveolar macrophages (aMacs) gradually decreased, while the proportions of Macs and monocytes (Monos) gradually increased, suggesting a chemotaxis process followed by a Mono-Mac differentiation process. Meanwhile, through ligand-receptor (LR) screening, we identified 9 Mac-specific interactions that were enriched during the progression and metastasis of lung cancer, which could potential promote M2 polarization or the infiltration of M2 Macs. Moreover, we found that the expression of SPP1 in Macs increased with lung cancer progression, and identified 9 genes that were correlated with the expression of SPP1 in Macs, which might also contribute to the immunosuppression process in lung cancer.

Conclusions

Our results revealed detailed changes in Macs at different stages of lung cancer progression and metastasis and provided potential therapeutic targets that could be used in future lung cancer treatments.

Distinct features of the regenerating heart uncovered through comparative single-cell profiling

Adult humans respond to heart injury by forming a permanent scar, yet other vertebrates are capable of robust and complete cardiac regeneration. Despite progress towards characterizing the mechanisms of cardiac regeneration in fish and amphibians, the large evolutionary gulf between mammals and regenerating vertebrates complicates deciphering which cellular and molecular features truly enable regeneration. To better define these features, we compared cardiac injury responses in zebrafish and medaka, two fish species that share similar heart anatomy and common teleost ancestry but differ in regenerative capability. We used single-cell transcriptional profiling to create a time-resolved comparative cell atlas of injury responses in all major cardiac cell types across both species. With this approach, we identified several key features that distinguish cardiac injury response in the non-regenerating medaka heart. By comparing immune responses to injury, we found altered cell recruitment and a distinct pro-inflammatory gene program in medaka leukocytes, and an absence of the injury-induced interferon response seen in zebrafish. In addition, we found a lack of pro-regenerative signals, including nrg1 and retinoic acid, from medaka endothelial and epicardial cells. Finally, we identified alterations in the myocardial structure in medaka, where they lack embryonic-like primordial layer cardiomyocytes, and fail to employ a cardioprotective gene program shared by regenerating vertebrates. Our findings reveal notable variation in injury response across nearly all major cardiac cell types in zebrafish and medaka, demonstrating how evolutionary divergence influences the hidden cellular features underpinning regenerative potential in these seemingly similar vertebrates.

Immunometabolism at the Heart of Cardiovascular Disease

Immune cell function among the myocardium, now more than ever, is appreciated to regulate cardiac function and pathophysiology. This is the case for both innate immunity, which includes neutrophils, monocytes, dendritic cells, and macrophages, as well as adaptive immunity, which includes T cells and B cells. This function is fueled by cell-intrinsic shifts in metabolism, such as glycolysis and oxidative phosphorylation, as well as metabolite availability, which originates from the surrounding extracellular milieu and varies during ischemia and metabolic syndrome. Immune cell crosstalk with cardiac parenchymal cells, such as cardiomyocytes and fibroblasts, is also regulated by complex cellular metabolic circuits. Although our understanding of immunometabolism has advanced rapidly over the past decade, in part through valuable insights made in cultured cells, there remains much to learn about contributions of in vivo immunometabolism and directly within the myocardium. Insight into such fundamental cell and molecular mechanisms holds potential to inform interventions that shift the balance of immunometabolism from maladaptive to cardioprotective and potentially even regenerative. Herein, we review our current working understanding of immunometabolism, specifically in the settings of sterile ischemic cardiac injury or cardiometabolic disease, both of which contribute to the onset of heart failure. We also discuss current gaps in knowledge in this context and therapeutic implications.