Reduced Lactate Production Research Articles

Dexmedetomidine Ameliorates Myocardial Ischemia-Reperfusion Injury by Inhibiting MDH2 Lactylation via Regulating Metabolic Reprogramming.

Myocardial ischemia-reperfusion injury (MIRI) significantly worsens the outcomes of patients with cardiovascular diseases. Dexmedetomidine (Dex) is recognized for its cardioprotective properties, but the related mechanisms, especially regarding metabolic reprogramming, have not been fully clarified. A total of 60 patients with heart valve disease are randomly assigned to Dex or control group. Blood samples are collected to analyze cardiac injury biomarkers and metabolomics. In vivo and vitro rat models of MIRI are utilized to assess the effects of Dex on cardiac function, lactate production, and mitochondrial function. It is found that postoperative CK-MB and cTNT levels are significantly lower in the Dex group. Metabolomics reveals that Dex regulates metabolic reprogramming and reduces lactate level. In Dex-treated rats, the myocardial infarction area is reduced, and myocardial contractility is improved. Dex inhibits glycolysis, reduces lactate, and improves mitochondrial function following MIRI. Lactylation proteomics identifies that Dex reduces the lactylation of Malate Dehydrogenase 2（MDH2), thus alleviating myocardial injury. Further studies reveal that MDH2 lactylation induces ferroptosis, leading to MIRI by impairing mitochondrial function. Mechanistic analyses reveal that Dex upregulates Nuclear Receptor Subfamily 3 Group C Member 1（NR3C1)phosphorylation, downregulates Pyruvate Dehydrogenase Kinase 4 (PDK4), and reduces lactate production and MDH2 lactylation. These findings provide new therapeutic targets and mechanisms for the treatment for MIRI.

Hypocretin-1/Hypocretin Receptor 1 Regulates Neuroplasticity and Cognitive Function through Hippocampal Lactate Homeostasis in Depressed Model.

Cognitive dysfunction is not only a common symptom of major depressive disorder, but also a more common residual symptom after antidepressant treatment and a risk factor for chronic and recurrent disease. The disruption of hypocretin regulation is known to be associated with depression, however, their exact correlation is remains to be elucidated. Hypocretin-1 levels are increased in the plasma and hypothalamus from chronic unpredictable mild stress (CUMS) model mice. Excessive hypocretin-1 conducted with hypocretin receptor 1 (HCRTR1) reduced lactate production and brain-derived neurotrophic factor (BDNF) expression by hypoxia-inducible factor-1α (HIF-1α), thus impairing adult hippocampal neuroplasticity, and cognitive impairment in CUMS model. Subsequently, it is found that HCRTR1 antagonists can reverse these changes. The direct effect of hypocretin-1 on hippocampal lactate production and cognitive behavior is further confirmed by intraventricular injection of hypocretin-1 and microPET-CT in rats. In addition, these mechanisms are further validated in astrocytes and neurons in vitro. Moreover, these phenotypes and changes in molecules of lactate transport pathway can be duplicated by specifically knockdown of HCRTR1 in hippocampal astrocytes. In summary, the results provide molecular and functional insights for involvement of hypocretin-1-HCRTR1 in altered cognitive function in depression.

Targeting hexokinase 2 to enhance anticancer efficacy of trichosanthin in HeLa and SCC25 cell models

Background and purpose: Trichosanthin (TCS) is a plant-based ribosome-inactivating protein exhibiting a range of pharmacological properties, including abortifacient and anticancer. However, the routine clinical use in cancer treatment was hampered by its antigenicity. Hexokinase 2 (HK2) is a pivotal regulator of glycolysis, where aberrant expression is observed in many cancers. This study investigates the anticancer effects and mechanisms of TCS in combination with benserazide (Benz), a HK2 inhibitor, in Hela and SCC25 cancer models. Experimental approach: MTT, colony-formation and cell cycle assays were performed to assess the cytotoxic effects of TCS and Benz in HeLa and SCC25 cells. Seahorse assay, western blotting, flow cytometry analysis and RNA sequencing were employed to investigate the pharmacological effects of the combo treatment. SCC25 cell xenograft mouse model was established for in vivo efficacy study. Key results: Combined use of TCS and Benz exhibited synergistic anticancer effects in both Hela and SCC25 cell models. The observed synergistic effects were attributed to the modulation of glycolysis by targeting HK2, leading to reduced lactate production and increased ROS accumulation which further inhibited colony formation and cell cycle progression, as well as triggered apoptosis. Moreover, this combination effectively inhibited NFκB/ERK signalling pathways, which were found to be significantly activated upon single use of TCS. It was found that the combination significantly suppressed the tumour growth in SCC25 cell xenograft mouse model. Conclusion: Our findings suggested that targeting HK2 and modulating glycolysis may offer a promising avenue for improving the therapeutic outcomes of TCS-based anticancer treatments.

Novel gold-based complex GC7 suppresses cancer cell proliferation via impacting energy metabolism mediated by mitochondria

Due to their pivotal roles in regulating energy metabolism and apoptosis, mitochondria in cancer cells have been considered a vulnerable and feasible target. Many anticancer agents, e.g., metal-based compounds, are found to target and disturb mitochondria primarily, which may lead to the disturbance of energy metabolism and, more importantly, the initiation of apoptosis. In this work, a gold-based complex 7 (GC7) was synthesized and evaluated in a series of different cancer cell lines. The anticancer efficacies of GC7 on cell viability, apoptosis, and colony formation were determined. Cellular thioredoxin reductase (TrxR) activity, oxygen consumption rate (OCR), glucose uptake, and lactate production following GC7 treatment were evaluated and analyzed. The Jeko-1 and A549 xenograft models were used to assess GC7’s tumor-suppressing effects. The results showed that GC7 possessed a broad-spectrum anticancer effect, with IC50 values ranging from 0.43 to 1.2 μM in multiple cancer cell lines, which was more potent than gold-based auranofin (∼2–6 folds). GC7 (0.3 and 1 μM) efficiently induced apoptosis of Jeko-1, A549, and HCT116 cells, and it suppressed the sphere formation of cancer stem cells GSC11 and GSC23 cells at 0.1 μM, and it completely eliminated colony at 0.3 μM. The preliminary mechanistic study showed that GC7 inhibited cellular TrxR activity, suppressed mitochondrial OCR, reduced mitochondrial membrane potential (MMP), decreased glucose uptake, and possibly suppressed glycolysis to reduce lactate production. GC7 was predicted to have a similar yet slightly different pharmacokinetic profile as auranofin. Finally, GC7 (20 mg/kg, oral, 5/week, or 3 mg/kg, IP, 3/week) significantly inhibited tumor growth. In conclusion, GC7 showed great potential in suppressing cancer cell proliferation, probably via inhibiting TrxR and impacting mitochondria-mediated energy metabolism.

Nanoscale Metal-Organic Layer Reprograms Cellular Metabolism to Enhance Photodynamic Therapy and Antitumor Immunity.

Abnormal cancer metabolism causes hypoxic and immunosuppressive tumor microenvironment (TME), which limits the antitumor efficacy of photodynamic therapy (PDT). Herein, we report a photosensitizing nanoscale metal-organic layer (MOL) with anchored 3-bromopyruvate (BrP), BrP@MOL, as a metabolic reprogramming agent to enhance PDT and antitumor immunity. BrP@MOL inhibited mitochondrial respiration and glycolysis to oxygenate tumors and reduce lactate production. This metabolic reprogramming enhanced reactive oxygen species generation during PDT and reshaped the immunosuppressive TME to enhance antitumor immunity. BrP@MOL-mediated PDT inhibited tumor growth by >90 % with 40 % of mice being tumor-free, rejected tumor re-challenge, and prevented lung metastasis. Further combination with immune checkpoint blockade potently regressed the tumors with >98 % tumor inhibition and 80 % of mice being tumor-free.

Nanoscale Metal‐Organic Layer Reprograms Cellular Metabolism to Enhance Photodynamic Therapy and Antitumor Immunity

AbstractAbnormal cancer metabolism causes hypoxic and immunosuppressive tumor microenvironment (TME), which limits the antitumor efficacy of photodynamic therapy (PDT). Herein, we report a photosensitizing nanoscale metal–organic layer (MOL) with anchored 3‐bromopyruvate (BrP), BrP@MOL, as a metabolic reprogramming agent to enhance PDT and antitumor immunity. BrP@MOL inhibited mitochondrial respiration and glycolysis to oxygenate tumors and reduce lactate production. This metabolic reprogramming enhanced reactive oxygen species generation during PDT and reshaped the immunosuppressive TME to enhance antitumor immunity. BrP@MOL‐mediated PDT inhibited tumor growth by >90 % with 40 % of mice being tumor‐free, rejected tumor re‐challenge, and prevented lung metastasis. Further combination with immune checkpoint blockade potently regressed the tumors with >98 % tumor inhibition and 80 % of mice being tumor‐free.

Sulforaphane reverses the enhanced NSCLC metastasis by regulating the miR-7-5p/c-Myc/LDHA axis in the acidic tumor microenvironment

BackgroundThe presence of distant metastasis at the time of initial diagnosis is a prevalent issue in non-small cell lung cancer (NSCLC), affecting around 30–40 % of the patients. Acidic tumor microenvironment (TME) provides favorable conditions that increase the invasiveness and aggressiveness of NSCLC. The activity of the glycolytic enzyme lactate dehydrogenase (LDHA) increases intracellular lactate accumulation, which creates an acidic TME. However, it is not yet known whether LDHA is involved in enhancing the metastatic potential of NSCLC and if LDHA is a druggable therapeutic target for NSCLC. PurposeWe aimed to investigate the molecular mechanisms underlying the enhanced NSCLC metastasis in acidic TME, and to explore whether sulforaphane (SFN), an active compound in Raphani Semen, can serve as a LDHA inhibitor to inhibit NSCLC metastasis in the acidic TME. MethodsTo mimic the acidic TME, NSCLC cells were cultured in acidic medium (pH 6.6), normal medium (pH 7.4) served as control. Western blotting, bioinformatic analysis, luciferase assay and rescue experiments were used to explore the mechanism and investigate the anti-metastatic effect of SFN both in vitro and in vivo. ResultsAcidic environment increases the expression of LDHA which in turn increases the production of lactic acid that contributes to the acidity of TME. Interestingly, elevated LDHA expression results from increased c-Myc expression, which transactivates LDHA. c-Myc expression is directly regulated by miR-7-5p. In vitro study shows that overexpression of miR-7-5p reverses the acidic pH-enhanced c-Myc and LDHA expressions and also abolishes the enhanced NSCLC cell migration. More importantly, SFN significantly inhibits NSCLC growth and metastasis by reducing lactate production via the miR-7-5p/c-Myc/LDHA axis. Besides, it also regulates the expressions of monocarboxylate transporter 1 (MCT1) and MCT4 that transport lactate across cell membrane. ConclusionsThe miR-7-5p/c-Myc/LDHA axis is involved in the enhanced NSCLC metastasis in the acidic TME. SFN, a novel LDHA inhibitor, reduces lactate production by targeting the miR-7–5p/c-Myc/LDHA axis, and hence inhibits NSCLC metastasis. Our findings not only delineate a novel mechanism, but also support the clinical translation of SFN as a novel therapeutic agent for treating metastatic NSCLC.

Mitochondrial puzzle in muscle: Linking the electron transport system to overweight.

Human skeletal muscle mitochondria regulate energy expenditure. Research has shown that the functionality of muscle mitochondria is altered in subjects with overweight, as well as in response to nutrient excess and calorie restriction. Two metabolic features of obesity and overweight are (1) incomplete muscular fatty acid oxidation and (2) increased circulating lactate levels. In this study, I propose that these metabolic disturbances may originate from a common source within the muscle mitochondrial electron transport system. Specifically, a reorganization of the supramolecular structure of the electron transport chain could facilitate the maintenance of readily accessible coenzyme Q pools, which are essential for metabolizing lipid substrates. This approach is expected to maintain effective electron transfer, provided that there is sufficient complex III to support the Q-cycle. Such an adaptation could enhance fatty acid oxidation and prevent mitochondrial overload, thereby reducing lactate production. These insights advance our understanding of the molecular mechanisms underpinning metabolic dysregulation in overweight states. This provides a basis for targeted interventions in the quest for metabolic health.

Astrocytic LRP1 enables mitochondria transfer to neurons and mitigates brain ischemic stroke by suppressing ARF1 lactylation

Low-density lipoprotein receptor-related protein-1 (LRP1) is an endocytic/signaling cell-surface receptor that regulates diverse cellular functions, including cell survival, differentiation, and proliferation. LRP1 has been previously implicated in the pathogenesis of neurodegenerative disorders, but there are inconsistencies in its functions. Therefore, whether and how LRP1 maintains brain homeostasis remains to be clarified. Here, we report that astrocytic LRP1 promotes astrocyte-to-neuron mitochondria transfer by reducing lactate production and ADP-ribosylation factor 1 (ARF1) lactylation. In astrocytes, LRP1 suppressed glucose uptake, glycolysis, and lactate production, leading to reduced lactylation of ARF1. Suppression of astrocytic LRP1 reduced mitochondria transfer into damaged neurons and worsened ischemia-reperfusion injury in a mouse model of ischemic stroke. Furthermore, we examined lactate levels in human patients with stroke. Cerebrospinal fluid (CSF) lactate was elevated in stroke patients and inversely correlated with astrocytic mitochondria. These findings reveal a protective role of LRP1 in brain ischemic stroke by enabling mitochondria-mediated astrocyte-neuron crosstalk.

IMG-31. DEUTERIUM METABOLIC IMAGING OF RESPONSE TO PRECISION THERAPY IN BRAF-V600E MUTANT GLIOMAS

Abstract BACKGROUND Oncogenic BRAF-V600E mutations are frequently observed in low- and high-grade gliomas in children. BRAF transduces signals from receptor tyrosine kinases to downstream effectors such as MEK1/2 and ERK, which regulate metabolism and proliferation. The combination of the BRAF-V600E inhibitor dabrafenib and the MEK1/2 inhibitor trametinib (Dab/Tra) improves patient survival. However, there is considerable variation in response durability, underscoring the need for early biomarkers of treatment response. Magnetic resonance imaging (MRI), which is the gold standard for patient management, does not reliably assess response to therapy. Since the BRAF/MEK pathway regulates metabolism, the goal of this study was to determine whether Dab/Tra induces alterations in glucose metabolism that can be leveraged for non-invasive imaging of response to therapy. METHODS We performed gene expression profiling, in vivo metabolomics, stable isotope tracing, and deuterium metabolic imaging in patient-derived and syngeneic BRAF-V600E mutant models (AM38, 2341). RESULTS Our studies indicate that Dab/Tra downregulates glucose metabolism to lactate in AM38 and 2341 cells. In vivo infusion with [U-13C]-glucose in mice bearing intracranial AM38 tumors confirmed that Dab/Tra downregulates 13C-lactate production in the tumor. Mechanistically, Dab/Tra destabilizes hypoxia inducible factor-1a and downregulates glycolytic genes, including SLC2A1, HK2, PFKFB3, and LDHA. Importantly, deuterium metabolic imaging using [6,6’-2H]-glucose, which is a clinical stage method of imaging glycolysis, shows a reduction in lactate production within 48h of treatment with Dab/Tra in AM38 tumor-bearing mice. CONCLUSIONS Our studies mechanistically link BRAF/MEK inhibition with reduced glycolysis and identify [6,6’-2H]-glucose as a novel, non-invasive agent for imaging early response to therapy. Since [6,6’-2H]-glucose is a safe, orally administered agent, our studies can be rapidly translated to the clinic, where they will provide physicians with a much-needed tool to determine whether patients are responding to therapy at an early timepoint that predicts extended survival.

DIPG-90. NON-INVASIVE METABOLIC IMAGING OF DIFFUSE MIDLINE GLIOMAS AND THEIR RESPONSE TO THERAPY

Abstract BACKGROUND Diffuse midline gliomas (DMGs) harboring histone H3K27M mutations are devastating pediatric brain tumors. ONC201 is the first drug in decades to extend survival in DMG patients and is likely to be widely used for treatment of DMGs. However, magnetic resonance imaging (MRI), the gold standard for patient management, does not provide a reliable readout of response to therapy. The Warburg effect describes the propensity of tumor cells to increase glucose uptake and conversion to lactate. Deuterium metabolic imaging of the Warburg effect using [6,6’-2H]-glucose provides the unparalleled opportunity to obtain a biologically meaningful readout of treatment response. Therefore, the goal of this study was to assess the utility of [6,6’-2H]-glucose for DMG imaging. METHODS We performed expression profiling and deuterium metabolic imaging in patient-derived and syngeneic DMG models. RESULTS Our studies indicate that DMG cells upregulate key components of the Warburg effect, including SLC2A1, SLC2A3, HK2, PFKFB3, PGK1, and LDHA relative to normal astrocytes. Silencing the H3K27M mutation in DMG cells reduced glycolytic gene expression. Spatially resolved 2D chemical shift imaging at 3T showed that lactate produced from [6,6’-2H]-glucose was localized to tumor vs. normal brain in mice bearing intracranial tumors. ONC201 downregulated glycolytic gene expression in DMG cells, an effect that was accompanied by reduced lactate production from [6,6’-2H]-glucose. Importantly, lactate production from [6,6’-2H]-glucose was reduced following treatment with ONC201 in mice bearing intracranial tumors at 3T, at an early timepoint independent of MRI-detectable volumetric alterations and predictive of extended survival. CONCLUSIONS Our studies mechanistically link the H3K27M mutation with the Warburg effect. Importantly, they identify [6,6’-2H]-glucose as a novel contrast agent for visualizing the metabolic lesion and imaging early response to therapy in DMGs. Since [6,6’-2H]-glucose is a safe, orally administered agent, our studies have the potential to be rapidly translated to the clinic, where they will provide physicians with a much-needed tool to determine whether DMG patients are responding to therapy.

Synthesis and biological characterization of an orally bioavailable lactate dehydrogenase-A inhibitor against pancreatic cancer

Lactate dehydrogenase-A (LDHA) is the major isoform of lactate dehydrogenases (LDH) that is overexpressed and linked to poor survival in pancreatic ductal adenocarcinoma (PDAC). Despite some progress, current LDH inhibitors have poor structural and physicochemical properties or exhibit unfavorable pharmacokinetics that have hampered their development. The present study reports the synthesis and biological evaluation of a novel class of LDHA inhibitors comprising a succinic acid monoamide motif. Compounds 6 and 21 are structurally related analogs that demonstrated potent inhibition of LDHA with IC50s of 46 nM and 72 nM, respectively. We solved cocrystal structures of compound 21-bound to LDHA that showed that the compound binds to a distinct allosteric site between the two subunits of the LDHA tetramer. Inhibition of LDHA correlated with reduced lactate production and reduction of glycolysis in MIA PaCa-2 pancreatic cancer cells. The lead compounds inhibit the proliferation of human pancreatic cancer cell lines and patient-derived 3D organoids and exhibit a synergistic cytotoxic effect with the OXPHOS inhibitor phenformin. Unlike current LDHA inhibitors, 6 and 21 have appropriate pharmacokinetics and ligand efficiency metrics, exhibit up to 73% oral bioavailability, and a cumulative half-life greater than 4 h in mice.

Experimental and computational investigation of the kinetic evolution of the glutaminolysis pathway and its interplay with the glycolysis pathway.

Exploring cellular responses necessitates studying real-time metabolic pathway kinetics, considering the adaptable nature of cells. Glycolysis and glutaminolysis are interconnected pathways fundamental to driving cellular metabolism, generating both energy and essential biosynthetic molecules. While prior studies explored glycolysis tracking, this research focuses on monitoring the kinetics of the glutaminolysis pathway by evaluating the effect of glutamine availability on glycolytic kinetics and by investigating the impact of a stimulator (oligomycin) and inhibitor (2DG) on the glycolytic flux in the presence of glutamine. Additionally, we adapted a rate equation model to provide improved understanding of the pathway kinetics. The experimental and simulated results indicate a significant reduction in extracellular lactate production in the presence of glutamine, reflecting a shift from glycolysis towards oxidative phosphorylation, due to the additional contribution of glutamine to energy production through the ETC (electron transport chain), reducing the glycolytic load. Oligomycin, an ETC inhibitor, increases lactate production to the original glycolytic level, despite the presence of glutamine. Nevertheless, its mechanism is influenced by the presence of glutamine, as predicted by the model. Conversely, 2DG notably reduces lactate production, affirming its glycolytic origin. The gradual increase in lactate production under the influence of 2DG implies increased activation of glutaminolysis as an alternative energy source. The model also simulates the varying metabolic responses under varying carbon/modulator concentrations. In conclusion, the kinetic model described here contributes to the understanding of changes in intracellular metabolites and their interrelationships in a way which would be challenging to obtain solely through kinetic assays.

FOXP3 targets KIF5A to increase lactate production and promote docetaxel resistance in lung adenocarcinoma.

A prominent cause of cancer-related fatalities with a poor prognosis is lung adenocarcinoma (LUAD). KIF5A, a crucial member of the kinesin superfamily, is linked to drug resistance in malignancies. This work aims to investigate the mechanism of KIF5A in docetaxel (DTX) resistance in LUAD cells. The results of bioinformatics analysis, qRT-PCR and western blot analysis show that KIF5A, which is involved in the glycolysis pathway, is highly expressed in LUAD and is positively correlated with glycolysis-related genes. We further verify that silencing of KIF5A inhibits DTX resistance, glycolysis, and lactate production in LUAD cells via cell counting kit-8 (CCK-8), flow cytometry, Seahorse XFe 96, lactate, and glucose assays. Mechanistically, KIF5A promotes DTX resistance in LUAD, and this effect is attenuated upon the addition of an LDHA inhibitor. Chromatin immunoprecipitation and dual-luciferase reporter assays reveal that FOXP3 transcriptionally activates KIF5A. Knockdown of FOXP3 reduces lactate production and enhances DTX sensitivity in LUAD, which is restored upon simultaneous overexpression of KIF5A. Our findings reveal that FOXP3 increases DTX resistance in LUAD cells by enhancing lactate production through the upregulation of KIF5A level. In conclusion, our study provides a novel treatment target for improving chemosensitivity in LUAD.

Dexmedetomidine hydrochloride plus sufentanil citrate inhibits glucose metabolism and epithelial‑mesenchymal transition in human esophageal squamous carcinoma KYSE30 cells by modulating the JAK/STAT3/HIF‑1α axis.

Dexmedetomidine hydrochloride (DEX-HCl) and sufentanil citrate (SFC) are commonly used anesthetic drugs for esophageal cancer (EC) surgery. The present study was performed to investigate the effect of DEX-HCl and SFC treatment on glucose metabolism and epithelial-mesenchymal transition in EC. Cell counting kit-8 (CCK8), clonogenic, wound healing and Transwell migration assays were performed to assess the effects of the DEX-HCl and SFC on KYSE30 cell proliferation, invasion and migration. Changes in lactate and glucose levels in KYSE30 cells were also detected. Western blot analysis was used to determine the protein expression levels of the JAK/STAT signaling pathway and glucose metabolism-related proteins. The results of CCK8, clonogenic and wound healing assays demonstrated that DEX-HCl and SFC inhibited KYSE30 cell proliferation, invasion and migration. Similarly, the combined DEX-HCl and SFC treatment significantly reduced lactate production, ATP production and glucose levels in KYSE30 cells. Western blotting indicated that DEX-HCl and SFC could reduce JAK/STAT and metastasis-related protein expression. Demonstrating a reduction in Hexokinase 2, matrix metallopeptidase 2 and 9, N-cadherin and lactate dehydrogenase A protein expression levels. The effects of DEX-HCl and SFC combined treatment were counteracted by the addition of JAK/STAT pathway activator RO8191, which suggested that DEX-HCl and SFC could serve a role in mediating the JAK/STAT signaling pathway in KYSE30 cells.

Disrupting glycolysis and DNA repair in anaplastic thyroid cancer with nucleus-targeting platinum nanoclusters

Cancer cells rely on aerobic glycolysis and DNA repair signals to drive tumor growth and develop drug resistance. Yet, fine-tuning aerobic glycolysis with the assist of nanotechnology, for example, dampening lactate dehydrogenase (LDH) for cancer cell metabolic reprograming remains to be investigated. Here we focus on anaplastic thyroid cancer (ATC) as an extremely malignant cancer with the high expression of LDH, and develop a pH-responsive and nucleus-targeting platinum nanocluster (Pt@TAT/sPEG) to simultaneously targets LDH and exacerbates DNA damage. Pt@TAT/sPEG effectively disrupts LDH activity, reducing lactate production and ATP levels, and meanwhile induces ROS production, DNA damage, and apoptosis in ATC tumor cells. We found Pt@TAT/sPEG also blocks nucleotide excision repair pathway and achieves effective tumor cell killing. In an orthotopic ATC xenograft model, Pt@TAT/sPEG demonstrates superior tumor growth suppression compared to Pt@sPEG and cisplatin. This nanostrategy offers a feasible approach to simultaneously inhibit glycolysis and DNA repair for metabolic reprogramming and enhanced tumor chemotherapy.

Glutamine suppresses senescence and promotes autophagy through glycolysis inhibition-mediated AMPKα lactylation in intervertebral disc degeneration

Regulating metabolic disorders has become a promising focus in treating intervertebral disc degeneration (IDD). A few drugs regulating metabolism, such as atorvastatin, metformin, and melatonin, show positive effects in treating IDD. Glutamine participates in multiple metabolic processes, including glutaminolysis and glycolysis; however, its impact on IDD is unclear. The current study reveals that glutamine levels are decreased in severely degenerated human nucleus pulposus (NP) tissues and aging Sprague-Dawley (SD) rat nucleus pulposus tissues, while lactate accumulation and lactylation are increased. Supplementary glutamine suppresses glycolysis and reduces lactate production, which downregulates adenosine-5’-monophosphate-activated protein kinase α (AMPKα) lactylation and upregulates AMPKα phosphorylation. Moreover, glutamine treatment reduces NP cell senescence and enhances autophagy and matrix synthesis via inhibition of glycolysis and AMPK lactylation, and glycolysis inhibition suppresses lactylation. Our results indicate that glutamine could prevent IDD by glycolysis inhibition-decreased AMPKα lactylation, which promotes autophagy and suppresses NP cell senescence.

Interleukin-22 inhibits cardiac fibrosis by regulating fibroblast metabolic reprogramming in myocardial infarction

Cardiac fibrosis, a significant characteristic of cardiovascular diseases, leads to ventricular remodeling and impaired cardiac function. In this study, we aimed to investigate the role of Interleukin-22 (IL-22) in myocardial fibrosis following myocardial infarction (MI) and to explore the underlying metabolic mechanisms. Here we analyzed the single-cell sequencing data and found that the level of aerobic glycolysis was significantly higher in cardiac fibrosis in MI patient, which we validated through in vivo experiments. Utilizing MI mouse model, these experiments revealed decreased serum IL-22 levels and increased levels of AngII and TGF-β1. However, treatment with exogenous IL-22 reversed these changes, reduced infarct size, and fibrosis. In vitro experiments demonstrated that IL-22 inhibited AngII-induced fibroblast-to-myofibroblast transition (FMT) by suppressing the expression of α-SMA, Cola1, and Cola3. Metabolic analysis indicated that IL-22 decreased the expression of glycolytic enzymes and reduced lactate production in cardiac fibroblasts. Further in vivo experiments confirmed the inhibitory effect of IL-22 on Pyruvate kinase isoform M2 (PKM2) levels in heart tissue. Additionally, IL-22 activated the c-Jun N-terminal kinase (JNK) pathway, while inhibition of JNK partially reversed IL-22's effect on PKM2 activity. These findings suggest that IL-22 mitigates cardiac fibrosis and FMT by inhibiting aerobic glycolysis by activating the JNK/PKM2 pathway. Our study highlights IL-22 as a potential therapeutic target for myocardial fibrosis and cardiovascular diseases, providing insights into its role in regulating fibrosis and glycolysis. These findings pave the way for developing targeted therapies and investigating additional metabolic pathways for improved treatment outcomes in the field of cardiovascular diseases.

All Three AKT Isoforms Can Upregulate Oxygen Metabolism and Lactate Production in Human Hepatocellular Carcinoma Cell Lines.

Hepatocellular carcinoma (HCC), the main pathological type of liver cancer, is related to risk factors such as viral hepatitis, alcohol intake, and non-alcoholic fatty liver disease (NAFLD). The constitutive activation of the PI3K/AKT signaling pathway is common in HCC and has essential involvement in tumor progression. The serine/threonine kinase AKT has several downstream substrates, which have been implicated in the regulation of cellular metabolism. However, the contribution of each of the three AKT isoforms, i.e., AKT1, AKT2 and AKT3, to HCC metabolism has not been comprehensively investigated. In this study, we analyzed the functional role of AKT1, AKT2 and AKT3 in HCC metabolism. The overexpression of activated AKT1, AKT2 and AKT3 isoforms in the human HCC cell lines Hep3B and Huh7 resulted in higher oxygen consumption rate (OCR), ATP production, maximal respiration and spare respiratory capacity in comparison to vector-transduced cells. Vice versa, lentiviral vector-mediated knockdowns of each AKT isoform reduced OCR in both cell lines. Reduced OCR rates observed in the three AKT isoform knockdowns were associated with reduced extracellular acidification rates (ECAR) and reduced lactate production in both analyzed cell lines. Mechanistically, the downregulation of OCR by AKT isoform knockdowns correlated with an increased phosphorylation of the pyruvate dehydrogenase on Ser232, which negatively regulates the activity of this crucial gatekeeper of mitochondrial respiration. In summary, our data indicate that each of the three AKT isoforms is able to upregulate OCR, ECAR and lactate production independently of each other in human HCC cells through the regulation of the pyruvate dehydrogenase.

BACH1 changes microglial metabolism and affects astrogenesis during mouse brain development

Microglia are highly heterogeneous as resident immune cells in the central nervous system. Although the proinflammatory phenotype of microglia is driven by the metabolic transformation in the disease state, the mechanism of metabolic reprogramming in microglia and whether it affects surrounding astrocyte progenitors have not been well elucidated. Here, we illustrate the communication between microglial metabolism and astrogenesis during embryonic development. The transcription factor BTB and CNC homology 1 (Bach1) reduces lactate production by inhibiting two key enzymes, HK2 and GAPDH, during glycolysis. Metabolic perturbation of microglia reduces lactate-dependent histone modification enrichment at the Lrrc15 promoter.The microglia-derived LRRC15 interacts with CD248 to participate in the JAK/STAT pathway and influence astrogenesis. In addition, Bach1cKO-Cx3 mice exhibit abnormal neuronal differentiation and anxiety-like behaviors. Altogether, this work suggests that the maintenance of microglia metabolic homeostasis during early brain development is closely related to astrogenesis, providing insights into astrogenesis and related diseases.