RESUMEN
The neonatal mammalian heart can regenerate following injury through cardiomyocyte proliferation but loses this potential by postnatal day 7. Stimulating adult cardiomyocytes to reenter the cell cycle remains unclear. Here we show that cardiomyocyte proliferation depends on its metabolic state. Given the connection between the tricarboxylic acid cycle and cell proliferation, we analyzed these metabolites in mouse hearts from postnatal day 0.5 to day 7 and found that α-ketoglutarate ranked highest among the decreased metabolites. Injection of α-ketoglutarate extended the window of cardiomyocyte proliferation during heart development and promoted heart regeneration after myocardial infarction by inducing adult cardiomyocyte proliferation. This was confirmed in Ogdh-siRNA-treated mice with increased α-ketoglutarate levels. Mechanistically, α-ketoglutarate decreases H3K27me3 deposition at the promoters of cell cycle genes in cardiomyocytes. Thus, α-ketoglutarate promotes cardiomyocyte proliferation through JMJD3-dependent demethylation, offering a potential approach for treating myocardial infarction.
Asunto(s)
Proliferación Celular , Histona Demetilasas con Dominio de Jumonji , Ácidos Cetoglutáricos , Infarto del Miocardio , Miocitos Cardíacos , Regeneración , Animales , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/farmacología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Infarto del Miocardio/patología , Infarto del Miocardio/metabolismo , Infarto del Miocardio/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Regeneración/efectos de los fármacos , Histona Demetilasas con Dominio de Jumonji/metabolismo , Histona Demetilasas con Dominio de Jumonji/genética , Ratones Endogámicos C57BL , Modelos Animales de Enfermedad , Animales Recién Nacidos , Células Cultivadas , Histonas/metabolismo , Ratones , Complejo Cetoglutarato Deshidrogenasa/metabolismo , Complejo Cetoglutarato Deshidrogenasa/genética , MasculinoRESUMEN
Changes in isocitrate dehydrogenases (IDH) lead to the production of the cancer-causing metabolite 2-hydroxyglutarate, making them a cause of cancer. However, the specific role of IDH in the progression of colon cancer is still not well understood. Our current study provides evidence that IDH2 is significantly increased in colorectal cancer (CRC) cells and actively promotes cell growth in vitro and the development of tumors in vivo. Inhibiting the activity of IDH2, either through genetic silencing or pharmacological inhibition, results in a significant increase in α-ketoglutarate (α-KG), indicating a decrease in the reductive citric acid cycle. The excessive accumulation of α-KG caused by the inactivation of IDH2 obstructs the generation of ATP in mitochondria and promotes the downregulation of HIF-1A, eventually inhibiting glycolysis. This dual metabolic impact results in a reduction in ATP levels and the suppression of tumor growth. Our study reveals a metabolic trait of colorectal cancer cells, which involves the active utilization of glutamine through reductive citric acid cycle metabolism. The data suggests that IDH2 plays a crucial role in this metabolic process and has the potential to be a valuable target for the advancement of treatments for colorectal cancer.
Asunto(s)
Subunidad alfa del Factor 1 Inducible por Hipoxia , Isocitrato Deshidrogenasa , Transducción de Señal , Isocitrato Deshidrogenasa/metabolismo , Isocitrato Deshidrogenasa/genética , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Animales , Línea Celular Tumoral , Ratones , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Ácidos Cetoglutáricos/metabolismo , Ciclo del Ácido Cítrico , Glucólisis , Ratones Desnudos , Progresión de la Enfermedad , Adenosina Trifosfato/metabolismo , Proliferación Celular , Reprogramación Celular , Mitocondrias/metabolismo , Neoplasias Intestinales/patología , Neoplasias Intestinales/metabolismo , Reprogramación MetabólicaRESUMEN
Histone lysine demethylase (KDM), AlkB homolog (ALKBH), and Ten-Eleven Translocation (TET) proteins are members of the 2-Oxoglutarate (2OG) and ferrous iron-dependent oxygenases, each of which harbors a catalytic domain centered on a double-stranded ß-helix whose topology restricts the regions directly involved in substrate binding. However, they have different catalytic functions, and the deeply structural biological reasons are not yet clear. In this review, the catalytic domain features of the three protein families are summarized from both sequence and structural perspectives. The construction of the phylogenetic tree and comparison of the structure show ten relatively conserved ß-sheets and three key regions with substantial structural differences. We summarize the relationship between three key regions of remarkable differences and the substrate compatibility of the three protein families. This review facilitates research into substrate-selective inhibition and bioengineering by providing new insights into the catalytic domains of KDM, ALKBH, and TET proteins.
Asunto(s)
Dominio Catalítico , Ácidos Cetoglutáricos , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/química , Humanos , Modelos Moleculares , Filogenia , Especificidad por Sustrato , Hierro/química , Hierro/metabolismo , Animales , Histona Demetilasas/química , Histona Demetilasas/metabolismo , Secuencia de AminoácidosRESUMEN
Cultured cancer cells frequently rely on the consumption of glutamine and its subsequent hydrolysis by glutaminase (GLS). However, this metabolic addiction can be lost in the tumour microenvironment, rendering GLS inhibitors ineffective in the clinic. Here we show that glutamine-addicted breast cancer cells adapt to chronic glutamine starvation, or GLS inhibition, via AMPK-mediated upregulation of the serine synthesis pathway (SSP). In this context, the key product of the SSP is not serine, but α-ketoglutarate (α-KG). Mechanistically, we find that phosphoserine aminotransferase 1 (PSAT1) has a unique capacity for sustained α-KG production when glutamate is depleted. Breast cancer cells with resistance to glutamine starvation or GLS inhibition are highly dependent on SSP-supplied α-KG. Accordingly, inhibition of the SSP prevents adaptation to glutamine blockade, resulting in a potent drug synergism that suppresses breast tumour growth. These findings highlight how metabolic redundancy can be context dependent, with the catalytic properties of different metabolic enzymes that act on the same substrate determining which pathways can support tumour growth in a particular nutrient environment. This, in turn, has practical consequences for therapies targeting cancer metabolism.
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Neoplasias de la Mama , Glutamina , Transaminasas , Glutamina/metabolismo , Humanos , Transaminasas/metabolismo , Transaminasas/antagonistas & inhibidores , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Línea Celular Tumoral , Femenino , Glutaminasa/antagonistas & inhibidores , Glutaminasa/metabolismo , Animales , Ácidos Cetoglutáricos/metabolismo , Adaptación Fisiológica , Ratones , Serina/metabolismo , Microambiente TumoralRESUMEN
The biosynthesis of many bacterial siderophores employs a member of a family of ligases that have been defined as NRPS-independent siderophore (NIS) synthetases. These NIS synthetases use a molecule of ATP to produce an amide linkage between a carboxylate and an amine. Commonly used carboxylate substrates include citrate or α-ketoglutarate, or derivatives thereof, while the amines are often hydroxamate derivatives of lysine or ornithine, or their decarboxylated forms cadaverine and putrescine. Enzymes that employ three substrates to catalyze a reaction may proceed through alternate mechanisms. Some enzymes use sequential mechanisms in which all three substrates bind prior to any chemical steps. In such mechanisms, substrates can bind in a random, ordered, or mixed fashion. Alternately, other enzymes employ a ping-pong mechanism in which a chemical step occurs prior to the binding of all three substrates. Here we describe an enzyme assay that will distinguish among these different mechanisms for the NIS synthetase, using IucA, an enzyme involved in the production of aerobactin, as the model system.
Asunto(s)
Péptido Sintasas , Sideróforos , Sideróforos/metabolismo , Sideróforos/química , Péptido Sintasas/metabolismo , Péptido Sintasas/química , Cinética , Especificidad por Sustrato , Pruebas de Enzimas/métodos , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Ácidos Cetoglutáricos/metabolismo , Ligasas/metabolismo , Ligasas/químicaRESUMEN
BACKGROUND: Helicobacter pylori (H. pylori) infection is critical in the development and occurrence of gastric cancer. H. pylori secretes gamma-glutamyl transferase (GGT), which affects energy metabolism and histone methylation in mesenchymal stem cells. However, its effect on human gastric epithelial cells remains unclear. This study aimed to investigate the effects of GGT on energy metabolism and histone methylation in gastric epithelial cells and determine its role in the development and progression of H. pylori-induced gastric cancer. METHODS: A GGT knockout H. pylori strain and mouse gastric cancer model were constructed, and alpha-ketoglutarate (α-KG) was added. The underlying mechanism was investigated using proteomics, immunohistochemistry, Western blotting, and other experimental assays. RESULTS: H. pylori can colonize the host's stomach and destroy the gastric epithelium. GGT secreted by H. pylori decreased the concentration of glutamine in the stomach and increased H3K9me3 and H3K27me3 expression, which promoted the proliferation and migration of gastric epithelial cells. Additionally, α-KG reversed this effect. GGT increased the tumorigenic ability of nude mice. GGT, secreted by H. pylori, promoted the expression of ribosomal protein L15 (RPL15), while GGT knockout and supplementation with α-KG and trimethylation inhibitors reduced RPL15 expression and Wnt signaling pathway expression. CONCLUSIONS: H. pylori secreted GGT decreased the expression of glutamine and α-KG in gastric epithelial cells, increased the expression of histones H3K9me3 and H3K27me3, and activated the Wnt signaling pathway through RPL15 expression, ultimately changing the biological characteristics of the gastric epithelium and promoting the occurrence of gastric cancer. Altered energy metabolism and histone hypermethylation are important factors involved in this process.
Asunto(s)
Metabolismo Energético , Células Epiteliales , Helicobacter pylori , Histonas , Neoplasias Gástricas , gamma-Glutamiltransferasa , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/patología , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/genética , Animales , Histonas/metabolismo , Metilación , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Células Epiteliales/patología , gamma-Glutamiltransferasa/metabolismo , gamma-Glutamiltransferasa/genética , Ratones , Humanos , Ratones Desnudos , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiología , Mucosa Gástrica/patología , Proliferación Celular , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Infecciones por Helicobacter/complicaciones , Ácidos Cetoglutáricos/metabolismoRESUMEN
In seeding plants, biosynthesis of the phytohormone ethylene, which regulates processes including fruit ripening and senescence, is catalyzed by 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase. The plant pathogen Pseudomonas savastanoi (previously classified as: Pseudomonas syringae) employs a different type of ethylene-forming enzyme (psEFE), though from the same structural superfamily as ACC oxidase, to catalyze ethylene formation from 2-oxoglutarate (2OG) in an arginine dependent manner. psEFE also catalyzes the more typical oxidation of arginine to give L-Δ1-pyrroline-5-carboxylate (P5C), a reaction coupled to oxidative decarboxylation of 2OG giving succinate and CO2. We report on the effects of C3 and/or C4 substituted 2OG derivatives on the reaction modes of psEFE. 1H NMR assays, including using the pure shift method, reveal that, within our limits of detection, none of the tested 2OG derivatives is converted to an alkene; some are converted to the corresponding ß-hydroxypropionate or succinate derivatives, with only the latter being coupled to arginine oxidation. The NMR results reveal that the nature of 2OG derivatization can affect the outcome of the bifurcating reaction, with some 2OG derivatives exclusively favoring the arginine oxidation pathway. Given that some of the tested 2OG derivatives are natural products, the results are of potential biological relevance. There are also opportunities for therapeutic or biocatalytic regulation of the outcomes of reactions catalyzed by 2OG-dependent oxygenases by the use of 2OG derivatives.
Asunto(s)
Proteínas Bacterianas , Etilenos , Ácidos Cetoglutáricos , Pseudomonas , Pseudomonas/enzimología , Pseudomonas/metabolismo , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/química , Etilenos/metabolismo , Etilenos/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Liasas/metabolismo , Liasas/química , Liasas/genética , Arginina/metabolismo , Arginina/química , Oxidación-ReducciónRESUMEN
The incidence of colorectal cancer (CRC) is closely linked to metabolic diseases. Accumulating evidence suggests the regulatory role of AMP-activated protein kinase (AMPK) in cancer metabolic reprogramming. In this study, wild-type and AMPK knockout mice were subjected to azoxymethane-induced and dextran sulfate sodium (AOM/DSS)-promoted colitis-associated CRC induction. A stable AMPK-deficient Caco-2 cell line was also established for the mechanistic studies. The data showed that AMPK deficiency accelerated CRC development, characterized by increased tumor number, tumor size, and hyperplasia in AOM/DSS-treated mice. The aggravated colorectal tumorigenesis resulting from AMPK ablation was associated with reduced α-ketoglutarate production and ten-eleven translocation hydroxylase 2 (TET2) transcription, correlated with the reduced mismatch repair protein mutL homolog 1 (MLH1) protein. Furthermore, in AMPK-deficient Caco-2 cells, the mRNA expression of mismatch repair and tumor suppressor genes, intracellular α-ketoglutarate, and the protein level of TET2 were also downregulated. AMPK deficiency also increased hypermethylation in the CpG islands of Mlh1 in both colonic tissues and Caco-2 cells. In conclusion, AMPK deficiency leads to reduced α-ketoglutarate concentration and elevates the suppressive epigenetic modifications of tumor suppressor genes in gut epithelial cells, thereby increasing the risk of colorectal tumorigenesis. Given the modifiable nature of AMPK activity, it holds promise as a prospective molecular target for the prevention and treatment of CRC.
Asunto(s)
Proteínas Quinasas Activadas por AMP , Azoximetano , Carcinogénesis , Neoplasias Colorrectales , Metilación de ADN , Dioxigenasas , Animales , Humanos , Ratones , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Azoximetano/toxicidad , Azoximetano/efectos adversos , Células CACO-2 , Carcinogénesis/genética , Colitis/inducido químicamente , Colitis/genética , Colitis/patología , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/inducido químicamente , Neoplasias Colorrectales/etiología , Sulfato de Dextran/toxicidad , Dioxigenasas/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Regulación Neoplásica de la Expresión Génica , Ácidos Cetoglutáricos/metabolismo , Ratones Noqueados , Homólogo 1 de la Proteína MutL/genética , Homólogo 1 de la Proteína MutL/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismoRESUMEN
Chronic hypoxia (CH) is commonly associated with various cardiovascular diseases, with cardiac hypertrophy being the most frequently observed alteration. Metabolic remodeling is another consequence seen in the hypoxic heart. However, the mechanistic linkage between metabolic remodeling and cardiac hypertrophy in the hypoxic heart remains unclear. In this study, wild-type C57BL/6J mice were subjected to CH for 4 wk. Echocardiography and morphological analysis were used to assess the cardiac effects. We found that 4 wk of CH led to significant cardiac hypertrophy in the mice, whereas cardiac function remained unchanged compared with normoxic mice. In addition, CH induced an elevation in cardiac alpha-ketoglutarate (α-KG) content. Promoting α-KG degradation in the CH hearts prevented CH-induced cardiac hypertrophy but led to noticeable cardiac dysfunction. Mechanistically, α-KG promoted the transcription of hypertrophy-related genes by regulating histone methylation. Silencing lysine-specific demethylase 5 (KDM5), a histone demethylation enzyme, blunted α-KG-induced transcription of hypertrophy-related genes. These data suggest that α-KG is required for CH-induced cardiac remodeling, thus establishing a connection between metabolic changes and cardiac remodeling in hypoxic hearts.NEW & NOTEWORTHY We reported that alpha-ketoglutarate (α-KG) is indispensable for chronic hypoxia (CH)-induced cardiac remodeling, which builds the bridge between metabolic intermediates and cardiac remodeling.
Asunto(s)
Cardiomegalia , Hipoxia , Ácidos Cetoglutáricos , Ratones Endogámicos C57BL , Remodelación Ventricular , Animales , Ácidos Cetoglutáricos/metabolismo , Hipoxia/metabolismo , Remodelación Ventricular/efectos de los fármacos , Cardiomegalia/metabolismo , Cardiomegalia/patología , Cardiomegalia/fisiopatología , Cardiomegalia/genética , Ratones , Masculino , Enfermedad Crónica , Histona Demetilasas/metabolismo , Histona Demetilasas/genética , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/patologíaRESUMEN
Alpha-ketoglutarate (α-KG), an endogenous intermediate of the tricarboxylic acid cycle, is involved in a variety of cellular metabolic pathways. It serves as an energy donor, a precursor of amino acid biosynthesis, and an epigenetic regulator. α-KG plays physiological functions in immune regulation, oxidative stress, and anti-aging as well. In recent years, it has been reported that the level of α-KG in the body is closely associated with metabolic syndrome, including obesity, hyperglycemia, and other pathological factors. Exogenous supplementation of α-KG improves obesity, blood glucose levels, and cardiovascular disease risks associated with metabolic syndrome. Furthermore, α-KG regulates the common pathological mechanisms of metabolic syndrome, suggesting the potential application prospect of α-KG in metabolic syndrome. In order to provide a theoretical basis for further exploration of the application of α-KG in metabolic syndrome, we focused on α-KG and metabolic syndrome in this article and summarized the latest research progress in the role of α-KG in improving the pathological condition and disease progression of metabolic syndrome. For the next step, researchers may focus on the co-pathogenesis of metabolic syndrome and investigate whether α-KG can be used to achieve the therapeutic goal of "homotherapy for heteropathy" in the treatment of metabolic syndrome.
Asunto(s)
Ácidos Cetoglutáricos , Síndrome Metabólico , Síndrome Metabólico/metabolismo , Ácidos Cetoglutáricos/metabolismo , Humanos , Obesidad/metabolismo , Obesidad/complicaciones , Animales , Estrés OxidativoRESUMEN
Abnormal polarization of adipose tissue macrophages (ATMs) results in low-grade systemic inflammation and insulin resistance (IR), potentially contributing to the development of diabetes. However, the underlying mechanisms that regulate the polarization of ATMs associated with gestational diabetes mellitus (GDM) remain unclear. Thus, we aimed to determine the effects of abnormal fatty acids on macrophage polarization and development of insulin resistance in GDM. Levels of fatty acids and inflammation were assessed in the serum samples and adipose tissues of patients with GDM. An in vitro cell model treated with palmitic acid was established, and the mechanisms of palmitic acid in regulating macrophage polarization was clarified. The effects of excessive palmitic acid on the regulation of histone methylations and IR were also explored in the high-fat diet induced GDM mice model. We found that pregnancies with GDM were associated with increased levels of serum fatty acids, and inflammation and IR in adipose tissues. Increased palmitic acid could induce mitochondrial dysfunction and excessive ROS levels in macrophages, leading to abnormal cytoplasmic and nuclear metabolism of succinate and α-ketoglutarate (αKG). Specifically, a decreased nuclear αKG/succinate ratio could attenuate the enrichment of H3K27me3 at the promoters of pro-inflammatory cytokines, such as IL-1ß, IL-6, and TNF-α, leading to cytokine secretion. Importantly, GDM mice treated with GSK-J4, an inhibitor of histone lysine demethylase, were protected from abnormal pro-inflammatory macrophage polarization and excessive production of pro-inflammatory cytokines. Our findings highlight the importance of the metabolism of αKG and succinate as transcriptional modulators in regulating the polarization of ATMs and the insulin sensitivity of adipose tissue, ensuring a normal pregnancy. This novel insight sheds new light on gestational fatty acid metabolism and epigenetic alterations associated with GDM.
Asunto(s)
Tejido Adiposo , Diabetes Gestacional , Resistencia a la Insulina , Ácidos Cetoglutáricos , Macrófagos , Ácido Palmítico , Ácido Succínico , Diabetes Gestacional/metabolismo , Diabetes Gestacional/patología , Embarazo , Ácido Palmítico/farmacología , Animales , Femenino , Ratones , Tejido Adiposo/metabolismo , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/patología , Macrófagos/metabolismo , Macrófagos/efectos de los fármacos , Humanos , Ácidos Cetoglutáricos/metabolismo , Ácido Succínico/metabolismo , Dieta Alta en Grasa/efectos adversos , Adulto , Ratones Endogámicos C57BL , Inflamación/metabolismo , Inflamación/patología , Modelos Animales de EnfermedadRESUMEN
Extracellular matrix (ECM) is a major component of the tumor environment, promoting the establishment of a pro-invasive behavior. Such environment is supported by both tumor- and stromal-derived metabolites, particularly lactate. In prostate cancer (PCa), cancer-associated fibroblasts (CAFs) are major contributors of secreted lactate, able to impact on metabolic and transcriptional regulation in cancer cells. Here, we describe a mechanism by which CAF-secreted lactate promotes in PCa cells the expression of genes coding for the collagen family. Lactate-exploiting PCa cells rely on increased α-ketoglutarate (α-KG) which activates the α-KG-dependent collagen prolyl-4-hydroxylase (P4HA1) to support collagen hydroxylation. De novo synthetized collagen plays a signaling role by activating discoidin domain receptor 1 (DDR1), supporting stem-like and invasive features of PCa cells. Inhibition of lactate-induced collagen hydroxylation and DDR1 activation reduces the metastatic colonization of PCa cells. Overall, these results provide a new understanding of the link between collagen remodeling/signaling and the nutrient environment exploited by PCa.
Asunto(s)
Colágeno , Matriz Extracelular , Ácido Láctico , Metástasis de la Neoplasia , Neoplasias de la Próstata , Masculino , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/genética , Humanos , Matriz Extracelular/metabolismo , Colágeno/metabolismo , Ácido Láctico/metabolismo , Línea Celular Tumoral , Fibroblastos Asociados al Cáncer/metabolismo , Fibroblastos Asociados al Cáncer/patología , Transducción de Señal , Regulación Neoplásica de la Expresión Génica , Animales , Ratones , Microambiente Tumoral , Ácidos Cetoglutáricos/metabolismo , HidroxilaciónRESUMEN
Severe bleeding from deep and irregular wounds poses a significant challenge in prehospital and surgical settings. To address this issue, we developed a novel chitosan-based hemostatic dressing with a magnetic targeting mechanism using Fe3O4, termed bovine serum albumin-modified Fe3O4 embedded in porous α-ketoglutaric acid/chitosan (BSA/Fe3O4@KA/CS). This dressing enhances hemostasis by magnetically guiding the agent to the wound site. In vitro, the hemostatic efficacy of BSA/Fe3O4@KA/CS is comparable to that of commercial chitosan (Celox™) and is not diminished by the modification. In vivo, BSA/Fe3O4@KA/CS demonstrated superior hemostatic performance and reduced blood loss compared to Celox™. The hemostatic mechanism of BSA/Fe3O4@KA/CS includes the concentration of solid blood components through water absorption, adherence to blood cells, and activation of the endogenous coagulation pathway. Magnetic field targeting is crucial in directing the dressing to deep hemorrhagic sites. Additionally, safety assessments have confirmed the biocompatibility and biodegradability of BSA/Fe3O4@KA/CS. In conclusion, we introduce a novel approach to modify chitosan using magnetic guidance for effective hemostasis, positioning BSA/Fe3O4@KA/CS as a promising candidate for managing various wounds.
Asunto(s)
Vendajes , Quitosano , Hemostáticos , Albúmina Sérica Bovina , Quitosano/química , Albúmina Sérica Bovina/química , Animales , Hemostáticos/química , Hemostáticos/farmacología , Porosidad , Ácidos Cetoglutáricos/química , Ácidos Cetoglutáricos/farmacología , Bovinos , Masculino , Hemorragia/tratamiento farmacológico , Hemorragia/terapia , RatonesRESUMEN
α-Ketoglutarate (AKG), a crucial intermediate in the tricarboxylic acid cycle, has been demonstrated to mitigate hyperlipidemia-induced dyslipidemia and endothelial damage. While hyperlipidemia stands as a major trigger for non-alcoholic fatty liver disease, the protection of AKG on hyperlipidemia-induced hepatic metabolic disorders remains underexplored. This study aims to investigate the potential protective effects and mechanisms of AKG against hepatic lipid metabolic disorders caused by acute hyperlipidemia. Our observations indicate that AKG effectively alleviates hepatic lipid accumulation, mitochondrial dysfunction, and loss of redox homeostasis in P407-induced hyperlipidemia mice, as well as in palmitate-injured HepG2 cells and primary hepatocytes. Mechanistic insights reveal that the preventive effects are mediated by activating the AMPK-PGC-1α/Nrf2 pathway. In conclusion, our findings shed light on the role and mechanism of AKG in ameliorating abnormal lipid metabolic disorders in hyperlipidemia-induced fatty liver, suggesting that AKG, an endogenous mitochondrial nutrient, holds promising potential for addressing hyperlipidemia-induced fatty liver conditions.
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Proteínas Quinasas Activadas por AMP , Hiperlipidemias , Ácidos Cetoglutáricos , Factor 2 Relacionado con NF-E2 , Estrés Oxidativo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Transducción de Señal , Animales , Hiperlipidemias/metabolismo , Hiperlipidemias/tratamiento farmacológico , Hiperlipidemias/complicaciones , Ratones , Estrés Oxidativo/efectos de los fármacos , Humanos , Factor 2 Relacionado con NF-E2/metabolismo , Proteínas Quinasas Activadas por AMP/metabolismo , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/farmacología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Transducción de Señal/efectos de los fármacos , Células Hep G2 , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Masculino , Metabolismo de los Lípidos/efectos de los fármacos , Hepatocitos/metabolismo , Hepatocitos/efectos de los fármacos , Hígado Graso/metabolismo , Hígado Graso/etiología , Hígado Graso/tratamiento farmacológico , Hígado Graso/prevención & control , Hígado Graso/patología , Modelos Animales de Enfermedad , Hígado/metabolismo , Hígado/efectos de los fármacos , Hígado/patologíaRESUMEN
N-Acetylnorloline synthase (LolO) is one of several iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases that catalyze sequential reactions of different types in the biosynthesis of valuable natural products. LolO hydroxylates C2 of 1-exo-acetamidopyrrolizidine before coupling the C2-bonded oxygen to C7 to form the tricyclic loline core. Each reaction requires cleavage of a C-H bond by an oxoiron(IV) (ferryl) intermediate; however, different carbons are targeted, and the carbon radicals have different fates. Prior studies indicated that the substrate-cofactor disposition (SCD) controls the site of H· abstraction and can affect the reaction outcome. These indications led us to determine whether a change in SCD from the first to the second LolO reaction might contribute to the observed reactivity switch. Whereas the single ferryl complex in the C2 hydroxylation reaction was previously shown to have typical Mössbauer parameters, one of two ferryl complexes to accumulate during the oxacyclization reaction has the highest isomer shift seen to date for such a complex and abstracts H· from C7 â¼ 20 times faster than does the first ferryl complex in its previously reported off-pathway hydroxylation of C7. The detectable hydroxylation of C7 in competition with cyclization by the second ferryl complex is not enhanced in 2H2O solvent, suggesting that the C2 hydroxyl is deprotonated prior to C7-H cleavage. These observations are consistent with the coordination of the C2 oxygen to the ferryl complex, which may reorient its oxo ligand, the substrate, or both to positions more favorable for C7-H cleavage and oxacyclization.
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Hierro , Ácidos Cetoglutáricos , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/química , Hierro/metabolismo , Hierro/química , Hidroxilación , Ciclización , Oxigenasas/metabolismo , Oxigenasas/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/químicaRESUMEN
Osteoarthritis (OA) is the most common degenerative joint disorder that causes disability in aged individuals, caused by functional and structural alterations of the knee joint. To investigate whether metabolic drivers might be harnessed to promote cartilage repair, a liquid chromatography-mass spectrometry (LC-MS) untargeted metabolomics approach was carried out to screen serum biomarkers in osteoarthritic rats. Based on the correlation analyses, α-ketoglutarate (α-KG) has been demonstrated to have antioxidant and anti-inflammatory properties in various diseases. These properties make α-KG a prime candidate for further investigation of OA. Experimental results indicate that α-KG significantly inhibited H2O2-induced cartilage cell matrix degradation and apoptosis, reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), increased superoxide dismutase (SOD) and glutathione (GSH)/glutathione disulfide (GSSG) levels, and upregulated the expression of ETV4, SLC7A11 and GPX4. Further mechanistic studies observed that α-KG, like Ferrostatin-1 (Fer-1), effectively alleviated Erastin-induced apoptosis and ECM degradation. α-KG and Fer-1 upregulated ETV4, SLC7A11, and GPX4 at the mRNA and protein levels, decreased ferrous ion (Fe2+) accumulation, and preserved mitochondrial membrane potential (MMP) in ATDC5 cells. In vivo, α-KG treatment inhibited ferroptosis in OA rats by activating the ETV4/SLC7A11/GPX4 pathway. Thus, these findings indicate that α-KG inhibits ferroptosis via the ETV4/SLC7A11/GPX4 signaling pathway, thereby alleviating OA. These observations suggest that α-KG exhibits potential therapeutic properties for the treatment and prevention of OA, thereby having potential clinical applications in the future.
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Ferroptosis , Ácidos Cetoglutáricos , Osteoartritis , Fosfolípido Hidroperóxido Glutatión Peroxidasa , Transducción de Señal , Ferroptosis/efectos de los fármacos , Animales , Osteoartritis/tratamiento farmacológico , Osteoartritis/metabolismo , Osteoartritis/patología , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/farmacología , Transducción de Señal/efectos de los fármacos , Ratas , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Fosfolípido Hidroperóxido Glutatión Peroxidasa/genética , Sistema de Transporte de Aminoácidos y+/metabolismo , Sistema de Transporte de Aminoácidos y+/genética , Masculino , Proteínas Proto-Oncogénicas c-ets/metabolismo , Proteínas Proto-Oncogénicas c-ets/genética , Ratas Sprague-Dawley , Apoptosis/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2.
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Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato , Hierro , Ácidos Cetoglutáricos , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/metabolismo , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/química , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/química , Hierro/metabolismo , Hierro/química , Humanos , Especificidad por Sustrato , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/química , Conformación Proteica , Uracilo/metabolismo , Uracilo/análogos & derivados , Uracilo/química , Simulación de Dinámica Molecular , Timina/análogos & derivadosRESUMEN
Enzymes of the central metabolism tend to assemble into transient supramolecular complexes. However, the functional significance of the interactions, particularly between enzymes catalyzing non-consecutive reactions, remains unclear. Here, by co-localizing two non-consecutive enzymes of the TCA cycle from Bacillus subtilis, malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD), in phase separated droplets we show that MDH-ICD interaction leads to enzyme agglomeration with a concomitant enhancement of ICD catalytic rate and an apparent sequestration of its reaction product, 2-oxoglutarate. Theory demonstrates that MDH-mediated clustering of ICD molecules explains the observed phenomena. In vivo analyses reveal that MDH overexpression leads to accumulation of 2-oxoglutarate and reduction of fluxes flowing through both the catabolic and anabolic branches of the carbon-nitrogen intersection occupied by 2-oxoglutarate, resulting in impeded ammonium assimilation and reduced biomass production. Our findings suggest that the MDH-ICD interaction is an important coordinator of carbon-nitrogen metabolism.
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Bacillus subtilis , Carbono , Ciclo del Ácido Cítrico , Isocitrato Deshidrogenasa , Ácidos Cetoglutáricos , Malato Deshidrogenasa , Nitrógeno , Nitrógeno/metabolismo , Carbono/metabolismo , Malato Deshidrogenasa/metabolismo , Malato Deshidrogenasa/genética , Bacillus subtilis/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/enzimología , Isocitrato Deshidrogenasa/metabolismo , Isocitrato Deshidrogenasa/genética , Ácidos Cetoglutáricos/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Compuestos de Amonio/metabolismoRESUMEN
OBJECTIVE: In this pilot study, we used untargeted metabolomics to identify biochemical mechanisms or biomarkers potentially underlying SLE-related fatigue. METHODS: Metabolon conducted untargeted metabolomic plasma profiling using ultrahigh performance liquid chromatography/tandem mass spectrometry on plasma samples of 23 Black females with systemic lupus erythematosus (SLE) and 21 no SLE controls. Fatigue phenotypes of general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation were measured with the reliable and valid Multidimensional Fatigue Inventory (MFI). RESULTS: A total of 290 metabolites were significantly different between the SLE and no SLE groups, encompassing metabolites related to glycolysis, TCA cycle activity, heme catabolism, branched chain amino acids, fatty acid metabolism, and steroids. Within the SLE group, controlling for age and co-morbidities, TCA cycle metabolites of alpha-ketoglutarate (AKG) and succinate were statistically significantly associated (p < .05) with physical and general fatigue. CONCLUSION: While pervasive perturbations in the entire TCA cycle have been implicated as a potential mechanism for fatigue, our results suggest individual metabolites of AKG and succinate may be potential biomarkers or targets of intervention for fatigue symptom management in SLE. Additionally, perturbations in heme metabolism in the SLE group provide additional insights into mechanisms that promote systemic inflammation.
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Biomarcadores , Ciclo del Ácido Cítrico , Fatiga , Lupus Eritematoso Sistémico , Metabolómica , Humanos , Femenino , Lupus Eritematoso Sistémico/sangre , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/fisiopatología , Proyectos Piloto , Fatiga/etiología , Fatiga/sangre , Adulto , Metabolómica/métodos , Biomarcadores/sangre , Persona de Mediana Edad , Negro o Afroamericano , Espectrometría de Masas en Tándem , Estudios de Casos y Controles , Ácido Succínico/sangre , Ácidos Cetoglutáricos/sangre , Cromatografía Líquida de Alta PresiónRESUMEN
Nonheme Fe(II) and 2-oxoglutarate (2OG)-dependent histone lysine demethylases 2A (KDM2A) catalyze the demethylation of the mono- or dimethylated lysine 36 residue in the histone H3 peptide (H3K36me1/me2), which plays a crucial role in epigenetic regulation and can be involved in many cancers. Although the overall catalytic mechanism of KDMs has been studied, how KDM2 catalysis takes place in contrast to other KDMs remains unknown. Understanding such differences is vital for enzyme redesign and can help in enzyme-selective drug design. Herein, we employed molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) to explore the complete catalytic mechanism of KDM2A, including dioxygen diffusion and binding, dioxygen activation, and substrate oxidation. Our study demonstrates that the catalysis of KDM2A is controlled by the conformational change of the second coordination sphere (SCS), specifically by a change in the orientation of Y222, which unlocks the 2OG rearrangement from off-line to in-line mode. The study demonstrates that the variant Y222A makes the 2OG rearrangement more favorable. Furthermore, the study reveals that it is the size of H3K36me3 that prevents the 2OG rearrangement, thus rendering the enzyme inactivity with trimethylated lysine. Calculations show that the SCS and long-range interacting residues that stabilize the HAT transition state in KDM2A differ from those in KDM4A, KDM7B, and KDM6A, thus providing the basics for the enzyme-selective redesign and modulation of KDM2A without influencing other KDMs.