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Nature Communications Oct 2023Mammalian lactate dehydrogenase D (LDHD) catalyzes the oxidation of D-lactate to pyruvate. LDHD mutations identified in patients with D-lactic acidosis lead to deficient...
Mammalian lactate dehydrogenase D (LDHD) catalyzes the oxidation of D-lactate to pyruvate. LDHD mutations identified in patients with D-lactic acidosis lead to deficient LDHD activity. Here, we perform a systematic biochemical study of mouse LDHD (mLDHD) and determine the crystal structures of mLDHD in FAD-bound form and in complexes with FAD, Mn and a series of substrates or products. We demonstrate that mLDHD is an Mn-dependent general dehydrogenase which exhibits catalytic activity for D-lactate and other D-2-hydroxyacids containing hydrophobic moieties, but no activity for their L-isomers or D-2-hydroxyacids containing hydrophilic moieties. The substrate-binding site contains a positively charged pocket to bind the common glycolate moiety and a hydrophobic pocket with some elasticity to bind the varied hydrophobic moieties of substrates. The structural and biochemical data together reveal the molecular basis for the substrate specificity and catalytic mechanism of LDHD, and the functional roles of mutations in the pathogenesis of D-lactic acidosis.
Topics: Animals; Mice; Humans; Acidosis, Lactic; Lactate Dehydrogenases; Lactic Acid; Hydroxy Acids; Binding Sites; L-Lactate Dehydrogenase; Mammals
PubMed: 37863926
DOI: 10.1038/s41467-023-42456-3 -
Cancer Letters Nov 2023Lung adenocarcinoma (LUAD) is one of the most prevalent and aggressive types of lung cancer. Metabolic reprogramming plays a critical role in the development and...
Combined inhibition of pyruvate dehydrogenase kinase 1 and lactate dehydrogenase a induces metabolic and signaling reprogramming and enhances lung adenocarcinoma cell killing.
Lung adenocarcinoma (LUAD) is one of the most prevalent and aggressive types of lung cancer. Metabolic reprogramming plays a critical role in the development and progression of LUAD. Pyruvate dehydrogenase kinase 1 (PDK1) and lactate dehydrogenase A (LDHA) are two key enzymes involved in glucose metabolism, whilst their aberrant expressions are often associated with tumorigenesis. Herein, we investigated the anticancer effects of combined inhibition of PDK1 and LDHA in LUAD in vitro and in vivo and its underlying mechanisms of action. The combination of a PDK1 inhibitor, 64, and a LDHA inhibitor, NHI-Glc-2, led to a synergistic growth inhibition in 3 different LUAD cell lines and more than additively suppressed tumor growth in the LUAD xenograft H1975 model. This combination also inhibited cellular migration and colony formation, while it induced a metabolic shift from glycolysis to oxidative phosphorylation (OXPHOS) resulting in mitochondrial depolarization and apoptosis in LUAD cells. These effects were related to modulation of multiple cell signaling pathways, including AMPK, RAS/ERK, and AKT/mTOR. Our findings demonstrate that simultaneous inhibition of multiple glycolytic enzymes (PDK1 and LDHA) is a promising novel therapeutic approach for LUAD.
Topics: Humans; Adenocarcinoma of Lung; Cell Death; Cell Line, Tumor; Cell Proliferation; Glycolysis; L-Lactate Dehydrogenase; Lactate Dehydrogenase 5; Lung Neoplasms; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Signal Transduction
PubMed: 37805163
DOI: 10.1016/j.canlet.2023.216425 -
Archives of Pharmacal Research Dec 2023Although tamoxifen (TAM) is widely used in patients with estrogen receptor-positive breast cancer, the development of tamoxifen resistance is common. The previous...
Although tamoxifen (TAM) is widely used in patients with estrogen receptor-positive breast cancer, the development of tamoxifen resistance is common. The previous finding suggests that the development of tamoxifen resistance is driven by epiregulin or hypoxia-inducible factor-1α-dependent glycolysis activation. Nonetheless, the mechanisms responsible for cancer cell survival and growth in a lactic acid-rich environment remain elusive. We found that the growth and survival of tamoxifen-resistant MCF-7 cells (TAMR-MCF-7) depend on glycolysis rather than oxidative phosphorylation. The levels of the glycolytic enzymes were higher in TAMR-MCF-7 cells than in parental MCF-7 cells, whereas the mitochondrial number and complex I level were decreased. Importantly, TAMR-MCF-7 cells were more resistant to low glucose and high lactate growth conditions. Isotope tracing analysis using C-lactate confirmed that lactate conversion to pyruvate was enhanced in TAMR-MCF-7 cells. We identified monocarboxylate transporter1 (MCT1) and lactate dehydrogenase B (LDHB) as important mediators of lactate influx and its conversion to pyruvate, respectively. Consistently, AR-C155858 (MCT1 inhibitor) inhibited the proliferation, migration, spheroid formation, and in vivo tumor growth of TAMR-MCF-7 cells. Our findings suggest that TAMR-MCF-7 cells depend on glycolysis and glutaminolysis for energy and support that targeting MCT1- and LDHB-dependent lactate recycling may be a promising strategy to treat patients with TAM-resistant breast cancer.
Topics: Female; Humans; Antineoplastic Agents, Hormonal; Breast Neoplasms; Cell Line, Tumor; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Lactates; MCF-7 Cells; Pyruvates; Tamoxifen
PubMed: 38048029
DOI: 10.1007/s12272-023-01474-x -
Clinical and Experimental Hypertension... Dec 2023Endothelial pyroptosis is a pathological mechanism of atherosclerosis (AS). Circular RNAs (circRNAs) are vital in AS progression by regulating endothelial cell...
Endothelial pyroptosis is a pathological mechanism of atherosclerosis (AS). Circular RNAs (circRNAs) are vital in AS progression by regulating endothelial cell functions. The study aimed to explore whether circ-USP9× regulated pyroptosis of endothelial cell to involve in AS development and the molecular mechanism. Pyroptosis was determined using lactate dehydrogenase (LDH) assay, enzyme linked immunosorbent assay (ELISA), flow cytometry, propidium iodide (PI) staining assay, and western blot. The mechanism of circ-USP9× was determined using RNA pull-down and RNA binding protein immunoprecipitation (RIP) assays. Results showed that circ-USP9× was upregulated in AS and oxidized low-density lipoprotein (ox-LDL)-treated human umbilical vein endothelial cells (HUVECs). Knockdown of circ-USP9× suppressed ox-LDL induced pyroptosis of HUVECs. Mechanically, circ-USP9× could bind to EIF4A3 in the cytoplasm. Moreover, EIF4A3 was bound to GSDMD and further affects GSDMD stability. Overexpression of EIF4A3 rescued cell pyroptosis induced by circ-USP9× depletion. In short, circ-USP9× interacted with EIF4A3 to enhance GSDMD stability, thus further promoting ox-LDL-induced pyroptosis of HUVECs. These findings suggested that circ-USP9× participates in AS progression and may be a potential therapeutic target for AS.
Topics: Humans; Apoptosis; Atherosclerosis; Cell Proliferation; DEAD-box RNA Helicases; Enzyme-Linked Immunosorbent Assay; Eukaryotic Initiation Factor-4A; Human Umbilical Vein Endothelial Cells; L-Lactate Dehydrogenase; Lipoproteins, LDL; MicroRNAs; Phosphate-Binding Proteins; Pore Forming Cytotoxic Proteins; Pyroptosis
PubMed: 36890708
DOI: 10.1080/10641963.2023.2186319 -
Translational Oncology Jan 2024Pleural effusions frequently signal disseminated cancer. Diagnostic markers of pleural malignancy at presentation that would assess cancer risk and would streamline...
INTRODUCTION
Pleural effusions frequently signal disseminated cancer. Diagnostic markers of pleural malignancy at presentation that would assess cancer risk and would streamline diagnostic decisions remain unidentified.
METHODS
A consecutive cohort of 323 patients with pleural effusion (PE) from different etiologies were recruited between 2013 and 2017 and was retrospectively analyzed. Data included history, chest X-ray, and blood/pleural fluid cell counts and biochemistry. Group comparison, receiver-operator characteristics, unsupervised hierarchical clustering, binary logistic regression, and random forests were used to develop the malignant pleural effusion detection (MAPED) score. MAPED was validated in an independent retrospective UK cohort (n = 238).
RESULTS
Five variables showed significant diagnostic power and were incorporated into the 5-point MAPED score. Age > 55 years, effusion size > 50% of the most affected lung field, pleural neutrophil count 〈 2,500/mm, effusion protein 〉 3.5 g/dL, and effusion lactate dehydrogenase > 250 U/L, each scoring one point, predicted underlying cancer with the area under curve(AUC) = 0.819 (P < 10) in the derivation cohort. The integrated discrimination improvement of MAPED scores showed an increase compared to cytology (p <0.001). Decision curve analysis indicated that the MAPED score generated net clinical benefit. In the validation dataset, the AUC of MAPED scores was 0.723 ( P = 3 × 10) for the MAPED score. Interestingly, MAPED correctly identified 33/42(79%) of cytology-negative patients that indeed had cancer.
CONCLUSIONS
The MAPED score identifies malignant pleural effusions with satisfactory accuracy and can be used complementary to cytology to streamline diagnostic procedures.
CONDENSED ABSTRACT
Diagnostic markers for malignant pleural effusions remain uncertain. The MAPED score identifies malignant pleural effusions and complements cytology and confers no additional risk to the patient or cost to the healthcare system.
PubMed: 37839174
DOI: 10.1016/j.tranon.2023.101800 -
Archives of Biochemistry and Biophysics Jun 2024Paracoccus denitrificans has a classical cytochrome-dependent electron transport chain and two alternative oxidases. The classical transport chain is very similar to...
Paracoccus denitrificans has a classical cytochrome-dependent electron transport chain and two alternative oxidases. The classical transport chain is very similar to that in eukaryotic mitochondria. Thus, P. denitrificans can serve as a model of the mammalian mitochondrion that may be more tractable in elucidating mechanisms of regulation of energy production than are mitochondria. In a previous publication we reported detailed studies on respiration in P. denitrificans grown aerobically on glucose or malate. We noted that P. denitrificans has large stores of lactate under various growth conditions. This is surprising because P. denitrificans lacks an NAD-dependent lactate dehydrogenase. The aim of this study was to investigate the mechanisms of lactate oxidation in P. denitrificans. We found that the bacterium grows well on either d-lactate or l-lactate. Growth on lactate supported a rate of maximum respiration that was equal to that of cells grown on glucose or malate. We report proteomic, metabolomic, and biochemical studies that establish that the metabolism of lactate by P. denitrificans is mediated by two non-NAD-dependent lactate dehydrogenases. One prefers d-lactate over l-lactate (D-iLDH) and the other prefers l-lactate (L-iLDH). We cloned and produced the D-iLDH and characterized it. The K for d-lactate was 34 μM, and for l-lactate it was 3.7 mM. Pyruvate was not a substrate, rendering the reaction unidirectional with lactate being converted to pyruvate for entry into the TCA cycle. The intracellular lactate was ∼14 mM such that both isomers could be metabolized by the enzyme. The enzyme has 1 FAD per molecule and utilizes a quinone rather than NAD as an electron acceptor. D-iLDH provides a direct entry of lactate reducing equivalents into the cytochrome chain, potentially explaining the high respiratory capacity of P. denitrificans in the presence of lactate.
Topics: Paracoccus denitrificans; Oxidation-Reduction; Lactic Acid; Glucose
PubMed: 38631502
DOI: 10.1016/j.abb.2024.109988 -
Brain and Behavior Jan 2024Ischemic stroke (IS) is one of the major global health problems. It is not clear whether there is a causal relationship between lactate dehydrogenase (LDH) and the risk... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND AND OBJECTIVE
Ischemic stroke (IS) is one of the major global health problems. It is not clear whether there is a causal relationship between lactate dehydrogenase (LDH) and the risk of IS attacks. The purpose of this study was to investigate whether LDH has a causal relationship with the development of IS.
METHODS
The genome-wide association data of LDH and IS were obtained through a Mendelian randomization-based platform. Single nucleotide polymorphisms (SNP) that were significantly associated with LDH were identified and used as instrumental variables, and a two-sample Mendelian randomization study was used to examine the causal relationship between LDH and IS. The statistical methods included Inverse-variance weighted approach, MR-Egger regression, and weighted median estimator.
RESULTS
We selected 15 SNPs of genome-wide significance from Genome-wide association study database with LDH as instrumental variables. A consistent causal association between LDH and IS was observed by different assessment methods. The results of the inverse-variance weighted method suggested an inverse association between LDH and higher genetic predictability of IS risk (OR, 0.997; 95%CI 0.995-0.999). The weighted median estimate showed consistent results with the MR-Egger method (weighted median estimate: OR, 0.995; 95%CI 0.992-0.999; MR-Egger method: OR, 0.996; 95%CI 0.992-0.999). The inverse-variance weighted method indicates a causal association between LDH and IS (β = -0.002563, SE = 0.00128, p = .0453). MR-Egger analysis (β = -0.004498, SE = 0.001877, p = .03) and the weighted median method suggested that LDH and IS also existed causal relationship (β = -0.004861, SE = 0.001801, p = .00695).
CONCLUSIONS
Our Mendelian randomization results suggest that LDH is inversely associated with the risk of developing IS, and are contrary to the results of previous observational studies.
Topics: Humans; Ischemic Stroke; Genome-Wide Association Study; L-Lactate Dehydrogenase; Mendelian Randomization Analysis; Polymorphism, Single Nucleotide
PubMed: 38376049
DOI: 10.1002/brb3.3352 -
Frontiers in Pharmacology 2023Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions... (Review)
Review
Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions encompass glycolysis, and its abnormal activity is associated with numerous diseases. Targeting LDH has emerged as a vital approach in drug discovery, leading to the identification of LDH inhibitors among natural compounds, such as polyphenols, alkaloids, and terpenoids. These compounds demonstrate therapeutic potential against LDH-related diseases, including anti-cancer effects. However, challenges concerning limited bioavailability, poor solubility, and potential toxicity must be addressed. Combining natural compounds with LDH inhibitors has led to promising outcomes in preclinical studies. This review highlights the promise of natural compounds as LDH inhibitors for treating cancer, cardiovascular, and neurodegenerative diseases.
PubMed: 37915411
DOI: 10.3389/fphar.2023.1275000 -
Stem Cell Research & Therapy Nov 2023The metabolic reprogramming of mesenchymal stem/stromal cells (MSC) favoring glycolysis has recently emerged as a new approach to improve their immunotherapeutic...
BACKGROUND
The metabolic reprogramming of mesenchymal stem/stromal cells (MSC) favoring glycolysis has recently emerged as a new approach to improve their immunotherapeutic abilities. This strategy is associated with greater lactate release, and interestingly, recent studies have proposed lactate as a functional suppressive molecule, changing the old paradigm of lactate as a waste product. Therefore, we evaluated the role of lactate as an alternative mediator of MSC immunosuppressive properties and its contribution to the enhanced immunoregulatory activity of glycolytic MSCs.
MATERIALS AND METHODS
Murine CD4 T cells from C57BL/6 male mice were differentiated into proinflammatory Th1 or Th17 cells and cultured with either L-lactate, MSCs pretreated or not with the glycolytic inductor, oligomycin, and MSCs pretreated or not with a chemical inhibitor of lactate dehydrogenase A (LDHA), galloflavin or LDH siRNA to prevent lactate production. Additionally, we validated our results using human umbilical cord-derived MSCs (UC-MSCs) in a murine model of delayed type 1 hypersensitivity (DTH).
RESULTS
Our results showed that 50 mM of exogenous L-lactate inhibited the proliferation rate and phenotype of CD4 T cell-derived Th1 or Th17 by 40% and 60%, respectively. Moreover, the suppressive activity of both glycolytic and basal MSCs was impaired when LDH activity was reduced. Likewise, in the DTH inflammation model, lactate production was required for MSC anti-inflammatory activity. This lactate dependent-immunosuppressive mechanism was confirmed in UC-MSCs through the inhibition of LDH, which significantly decreased their capacity to control proliferation of activated CD4 and CD8 human T cells by 30%.
CONCLUSION
These findings identify a new MSC immunosuppressive pathway that is independent of the classical suppressive mechanism and demonstrated that the enhanced suppressive and therapeutic abilities of glycolytic MSCs depend at least in part on lactate production.
Topics: Humans; Male; Animals; Mice; Mice, Inbred C57BL; Lactic Acid; Immunosuppressive Agents; Mesenchymal Stem Cells; Cell Differentiation
PubMed: 37981698
DOI: 10.1186/s13287-023-03549-4 -
Lung Aug 2023Hemorrhagic stroke (HS) is a devastating complication during extracorporeal membrane oxygenation (ECMO) but markers of risk stratification during COVID-19 are unknown....
PURPOSE
Hemorrhagic stroke (HS) is a devastating complication during extracorporeal membrane oxygenation (ECMO) but markers of risk stratification during COVID-19 are unknown. Lactate dehydrogenase (LDH) is a readily available biomarker of cell injury and permeability. We sought to determine whether an elevated LDH before ECMO placement is related to the occurrence of HS during ECMO for COVID-19.
METHODS
Adult patients with COVID-19 requiring ECMO between March 2020 and February 2022 were included. LDH values prior to ECMO placement were captured. Patients were categorized into high (> 750 U/L) or low (≤ 750 U/L) LDH groups. Multivariable regression modeling was used to determine the association between LDH and HS during ECMO.
RESULTS
There were 520 patients that underwent ECMO placement in 17 centers and 384 had an available LDH. Of whom, 122 (32%) had a high LDH. The overall incidence of HS was 10.9%, and patients with high LDH had a higher incidence of HS than those with low LDH level (17% vs 8%, p = 0.007). At 100 days, the probability of a HS was 40% in the high LDH group and 23% in those with a low LDH, p = 0.002. After adjustment for clinical covariates, high LDH remained associated with subsequent HS (aHR: 2.64, 95% CI 1.39-4.92). Findings were similar when restricting to patients supported by venovenous ECMO only.
CONCLUSION
Elevated LDH prior to ECMO cannulation is associated with a higher incidence of HS during device support. LDH can risk stratify cases for impending cerebral bleeding during ECMO.
Topics: Adult; Humans; COVID-19; Extracorporeal Membrane Oxygenation; Hemorrhagic Stroke; Retrospective Studies; Lactate Dehydrogenases
PubMed: 37401936
DOI: 10.1007/s00408-023-00630-w