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Air pollution has been recognized as a contributing factor to sleep disorders (SD), which have been correlated with an elevated susceptibility to a variety of human diseases. Nevertheless, research has not definitively established a connection between SD and interior decorative volatile organic compounds (ID-VOCs), a significant indoor air pollutant. In this study, we employed a mouse model exposed to ID-VOCs to explore the impacts of ID-VOCs exposure on sleep patterns and the potential underlying mechanism. Of the 23 key compositions of ID-VOCs identified, aromatic hydrocarbons were found to be the most prevalent. Exposure to ID-VOCs in mice resulted in SD, characterized by prolonged wake fullness and decreased sleep during the light period. ID-VOCs exposure triggered neuroinflammatory responses in the suprachiasmatic nucleus (SCN), with microglia activation leading to the overproduction of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and complement component 1q (C1q), ultimately inducing A1 astrocytes. Consequently, the upregulation of branched chain amino acid transaminase 2 (BCAT2) in A1 astrocytes resulted in elevated extracellular glutamate and disruption of the wake-sleep transition mechanism, which might be the toxicological mechanism of SD caused by ID-VOCs.
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Contaminantes Atmosféricos , Trastornos del Sueño-Vigilia , Compuestos Orgánicos Volátiles , Animales , Ratones , Contaminantes Atmosféricos/toxicidad , Trastornos del Sueño-Vigilia/inducido químicamente , Enfermedades Neuroinflamatorias/inducido químicamente , Contaminación del Aire Interior/efectos adversos , Masculino , Transducción de Señal/efectos de los fármacos , Ácido Glutámico/metabolismoRESUMEN
SCOPE: The global prevalence of obesity has significantly increased, presenting a major health challenge. High-fat diet (HFD)-induced obesity is closely related to the disease severity of psoriasis, but the mechanism is not fully understood. METHODS AND RESULTS: The study utilizes the HFD-induced obesity model along with an imiquimod (IMQ)-induced psoriasis-like mouse model (HFD-IMQ) to conduct transcriptomics and metabolomic analyses. HFD-induced obese mice exhibits more severe psoriasis-like lesions compared to normal diet (ND)-IMQ mice. The expression of genes of the IL-17 signaling pathway (IL-17A, IL-17F, S100A9, CCL20, CXCL1) is significantly upregulated, leading to an accumulation of T cells and neutrophils in the skin. Moreover, the study finds that there is an inhibition of the branched-chain amino acids (BCAAs) catabolism pathway, and the key gene branched-chain amino transferase 2 (Bcat2) is significantly downregulated, and the levels of leucine, isoleucine, and valine are elevated in the HFD-IMQ mice. Furthermore, the study finds that the peroxisome proliferator-activated receptor gamma (PPAR γ) is inhibited, while STAT3 activity is promoted in HFD-IMQ mice. CONCLUSION: HFD-induced obesity significantly amplifies IL-17 signaling and exacerbates psoriasis, with a potential role played by Bcat2-mediated BCAAs metabolism. The study suggests that BCAA catabolism and PPAR γ-STAT3 exacerbate inflammation in psoriasis with obesity.
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Aminoácidos de Cadena Ramificada , Dieta Alta en Grasa , Obesidad , Psoriasis , Transaminasas , Animales , Masculino , Ratones , Aminoácidos de Cadena Ramificada/metabolismo , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Imiquimod , Inflamación/metabolismo , Interleucina-17/metabolismo , Interleucina-17/genética , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/metabolismo , Obesidad/complicaciones , PPAR gamma/metabolismo , PPAR gamma/genética , Psoriasis/metabolismo , Psoriasis/patología , Transducción de Señal , Piel/metabolismo , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT3/genética , Transaminasas/metabolismoRESUMEN
OBJECTIVE: Branched-chain amino acid (BCAA) metabolism is involved in the development of colorectal cancer (CRC); however, the underlying mechanism remains unclear. Therefore, this study investigates the role of BCAA metabolism in CRC progression. METHODS: Dietary BCAA was administered to both azoxymethane-induced and azoxymethane/dextran sodium sulfate-induced CRC mouse models. The expression of genes related to BCAA metabolism was determined using RNA sequencing. Adjacent tissue samples, obtained from 58 patients with CRC, were subjected to quantitative real-time PCR and immunohistochemical analysis. Moreover, the suppressive role of branched-chain aminotransferase 2 (BCAT2) in cell proliferation, apoptosis, and xenograft mouse models was investigated. Alterations in BCAAs and activation of downstream pathways were also assessed using metabolic analysis and western blotting. RESULTS: High levels of dietary BCAA intake promoted CRC tumorigenesis in chemical-induced CRC and xenograft mouse models. Both the mRNA and protein levels of BCAT2 were decreased in tumor tissues of patients with CRC compared to those in normal tissues. Proliferation assays and xenograft models confirmed the suppressive role of BCAT2 in CRC progression. Furthermore, the accumulation of BCAAs caused by BCAT2 deficiency facilitated the chronic activation of mTORC1, thereby mediating the oncogenic effect of BCAAs. CONCLUSION: BCAT2 deficiency promotes CRC progression through inhibition of BCAAs metabolism and chronic activation of mTORC1.
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Neoplasias Colorrectales , Proteínas Gestacionales , Humanos , Ratones , Animales , Aminoácidos de Cadena Ramificada/metabolismo , ARN Mensajero , Diana Mecanicista del Complejo 1 de la Rapamicina , Azoximetano , Neoplasias Colorrectales/inducido químicamente , Neoplasias Colorrectales/genética , Transaminasas/genética , Transaminasas/metabolismo , Proteínas Gestacionales/metabolismo , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/metabolismoRESUMEN
Melanoma is the most lethal skin cancer originating from the malignant transformation of epidermal melanocyte. The dysregulation of cellular metabolism is a hallmark of cancer, including in melanoma. Aberrant branched-chain amino acids (BCAA) metabolism and related enzymes has been greatly implicated in the progression of multiple types of cancer, whereas remains far from understood in melanoma. Herein, we reported that the critical BCAA metabolism enzyme branched-chain amino acid transaminase 2 (BCAT2) is an oncogenic factor in melanoma by activating lipogenesis via the epigenetic regulation of fatty acid synthase (FASN) and ATP-citrate lyase (ACLY) expressions. Firstly, we found that BCAT2 expression was prominently increased in melanoma, and highly associated with clinical stage. Then, it was proved that the deficiency of BCAT2 led to impaired tumor cell proliferation, invasion and migration in vitro, and tumor growth and metastasis in vivo. Further, RNA sequencing technology and a panel of biochemical assays demonstrated that BCAT2 regulated de novo lipogenesis via the regulation of the expressions of both FASN and ACLY. Mechanistically, the inhibition of BCAT2 suppressed the generation of intracellular acetyl-CoA, mitigating P300-dependent histone acetylation at the promoter of FASN and ACLY, and thereby their transcription. Ultimately, zinc finger E-box binding homeobox 1 (ZEB1) was identified as the upstream transcriptional factor responsible for BCAT2 up-regulation in melanoma. Our results demonstrate that BCAT2 promotes melanoma progression by epigenetically regulating FASN and ACLY expressions via P300-dependent histone acetylation. Targeting BCAT2 could be exploited as a promising strategy to restrain tumor progression in melanoma.
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Melanoma , Proteínas Gestacionales , Humanos , Lipogénesis/genética , ATP Citrato (pro-S)-Liasa/genética , ATP Citrato (pro-S)-Liasa/metabolismo , Histonas/metabolismo , Epigénesis Genética , Melanoma/genética , Transaminasas/genética , Proteínas Gestacionales/genética , Proteínas Gestacionales/metabolismo , Antígenos de Histocompatibilidad Menor/metabolismo , Acido Graso Sintasa Tipo I/genéticaRESUMEN
Background: Diabetic retinopathy (DR) is deemed a microangiopathy and neurodegenerative disorder, which is a primary reason of visual impairment in the world. Ferritinophagy is a critical regulator of ferroptosis and has a vital part in the etiopathogenesis of DR. Nevertheless, its molecular mechanism in DR remains to be expounded. Methods: The GSE146615 dataset was adopted to identify ferritinophagy-related differentially expressed genes (FRDEGs). The interactions and biological functions of the genes were described by means of functional enrichment analysis (FEA). The enriched gene sets were analyzed utilizing gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA). Identification of hub genes was performed utilizing protein-protein interaction (PPI) analysis. mRNA-miRNA, mRNA-transcription factors (TF), mRNA-drugs, mRNA-RNA-binding proteins (RBP) interaction networks were constructed. In addition, datasets GSE60436 and GSE94019 were utilized for validation. The diagnostic performance of FRDEGs was assessed by means of receiver-operating characteristic curve monofactor analysis, followed by immune infiltration analysis. Lastly, quantitative real-time polymerase chain reaction (qRT-PCR) was implemented to analyze the validation of genes. Results: In total, the identification of eight FRDEGs was completed utilizing differential expression analysis. FEA mainly implicated the autophagy of mitochondrion, mitochondrion disassembly, autophagosome assembly, and organization pathways. GSEA and GSVA mainly implicated the interferon alpha response, ultraviolet response up, interferon gamma response, apical junction, pical surface, and allograft rejection pathways. BECN1 and HERC2 displayed high diagnostic accuracies in validation sets. Immune infiltration analysis revealed that several immune cells related to ferritinophagy may be play potential roles in DR. Finally, qRT-PCR was utilized to validate the upregulated expression of BECN1 as well as the downregulated expression of BCAT2 and ATG7 in the DR model. Conclusion: BECN1, HERC2, ATG7, and BCAT2 act as potential biomarkers for DR and might regulate ferritinophagy and the immune microenvironment to influence its development and progression. This research can provide new insights into pathogenesis of DR related to ferritinophagy.
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Diabetes Mellitus , Retinopatía Diabética , Ferroptosis , MicroARNs , Humanos , Retinopatía Diabética/genética , Autofagia/genética , Interferón gammaRESUMEN
The tuberous sclerosis complex (TSC) gene products (TSC1/TSC2) negatively regulate mTORC1. Although mTORC1 inhibitors are used for the treatment of TSC, incomplete tumor elimination and the adverse effects from long-term administration are problems that need to be solved. Branched-chain amino acid (BCAA) metabolism is involved in the growth of many tumor cells via the mTORC1 pathway. However, it remains unclear how BCAA metabolism affects the growth of mTORC1-dysregulated tumors. We show here that the expression of branched-chain amino transferase1 (Bcat1) was suppressed in Tsc2-deficient murine renal tumor cells either by treatment with rapamycin or restoration of Tsc2 expression suggesting that Bcat1 is located downstream of Tsc2-mTORC1 pathway. We also found that gabapentin, a Bcat1 inhibitor suppressed the growth of Tsc2-deficient tumor cells and increased efficacy when combined with rapamycin. We investigate the functional importance of Bcat1 and the mitochondrial isoform Bcat2 by inhibiting each enzyme separately or both together by genome editing and shRNA in Tsc2-deficient cells. We found that deficiency of both enzymes, but not either alone, inhibited cell growth, indicating that BCAA-metabolic reactions support Tsc2-deficient cell proliferation. Our results indicate that inhibition of Bcat1 and Bcat2 by specific drugs should be a useful method for TSC treatment.
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Esclerosis Tuberosa , Ratones , Animales , Esclerosis Tuberosa/metabolismo , Esclerosis Tuberosa/patología , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Línea Celular Tumoral , Sirolimus/farmacología , TransaminasasRESUMEN
N6-methyladenosine (m6A), the most prevalent internal modification in mammalian mRNAs, is involved in many pathological processes. METTL16 is a recently identified m6A methyltransferase. However, its role in leukemia has yet to be investigated. Here, we show that METTL16 is a highly essential gene for the survival of acute myeloid leukemia (AML) cells via CRISPR-Cas9 screening and experimental validation. METTL16 is aberrantly overexpressed in human AML cells, especially in leukemia stem cells (LSCs) and leukemia-initiating cells (LICs). Genetic depletion of METTL16 dramatically suppresses AML initiation/development and maintenance and significantly attenuates LSC/LIC self-renewal, while moderately influencing normal hematopoiesis in mice. Mechanistically, METTL16 exerts its oncogenic role by promoting expression of branched-chain amino acid (BCAA) transaminase 1 (BCAT1) and BCAT2 in an m6A-dependent manner and reprogramming BCAA metabolism in AML. Collectively, our results characterize the METTL16/m6A/BCAT1-2/BCAA axis in leukemogenesis and highlight the essential role of METTL16-mediated m6A epitranscriptome and BCAA metabolism reprograming in leukemogenesis and LSC/LIC maintenance.
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Autorrenovación de las Células , Leucemia Mieloide Aguda , Ratones , Humanos , Animales , Leucemia Mieloide Aguda/patología , Carcinogénesis/patología , ARN Mensajero/metabolismo , Aminoácidos de Cadena Ramificada/genética , Aminoácidos de Cadena Ramificada/metabolismo , Células Madre Neoplásicas/patología , Mamíferos/metabolismo , Transaminasas/genética , Transaminasas/metabolismo , Metiltransferasas/genética , Metiltransferasas/metabolismoRESUMEN
BCAT2-mediated branched-chain amino acid (BCAA) catabolism is critical for pancreatic ductal adenocarcinoma (PDAC) development, especially at an early stage. However, whether a high-BCAA diet promotes PDAC development in vivo, and the underlying mechanism of BCAT2 upregulation, remain undefined. Here, we find that a high-BCAA diet promotes pancreatic intraepithelial neoplasia (PanIN) progression in LSL-KrasG12D/+ ; Pdx1-Cre (KC) mice. Moreover, we screened with an available deubiquitylase library which contains 31 members of USP family and identified that USP1 deubiquitylates BCAT2 at the K229 site. Furthermore, BCAA increases USP1 protein at the translational level via the GCN2-eIF2α pathway both in vitro and in vivo. More importantly, USP1 inhibition recedes cell proliferation and clone formation in PDAC cells and attenuates pancreas tumor growth in an orthotopic transplanted mice model. Consistently, a positive correlation between USP1 and BCAT2 is found in KC; LSL-KrasG12D/+ ; p53flox/+ ; Pdx1-Cre mice and clinical samples. Thus, a therapeutic targeting USP1-BCAT2-BCAA metabolic axis could be considered as a rational strategy for treatment of PDAC and precisive dietary intervention of BCAA has potentially translational significance.
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Ruscogenin (RUS), a natural steroidal sapogenin, exerts various biological activities. However, its effectiveness for preventing myocardial ischemia (MI) and its molecular mechanisms need further clarification. The model of MI mice and oxygen-glucose deprivation-induced cardiomyocytes injury was performed. RUS significantly alleviated MI, as evidenced by decreased infarct size, ameliorated biochemical indicators and cardiac pathological features, and markedly inhibited ferroptosis by means of the up-regulation of GPX4 and down-regulation of ACSL4 and FLC. Simultaneously, RUS notably mitigated cell injury and oxidative stress, and ameliorated ferroptosis in vitro. Subsequently, HPLC-Q-TOF/MS-based metabolomics identified BCAT1/BCAT2 as possible regulatory enzymes responsible for the cardioprotection of RUS. Importantly, RUS treatment significantly increased the expression of BCAT1 and BCAT2 in MI. Furthermore, we found that BCAT1 or BCAT2 siRNA significantly decreased cell viability, promoted ferroptosis, and increased Keap1 expression, and induced Nrf2 and HO-1 degradation in cardiomyocytes. Conversely, cardiac overexpression of BCAT1 or BCAT2 in MI mice activated the Keap1/Nrf2/HO-1 pathway. Moreover, RUS significantly activated the Keap1/Nrf2/HO-1 pathway in MI, whereas BCAT1 or BCAT2 siRNA partially weakened the protective effects of RUS, suggesting that RUS might suppress myocardial injury through BCAT1 and BCAT2. Overall, this study demonstrated that BCAT1/BCAT2 could alleviate MI-induced ferroptosis through the activation of the Keap1/Nrf2/HO-1 pathway and RUS exerted cardioprotective effects via BCAT1/BCAT2.
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Although research on the metabolism related to gastric cancer (GC) is gradually gaining increasing interest, there are few studies regarding metabolism-related genes in GC. Understanding the characteristic changes of metabolism-related genes at the transcriptional and protein levels in GC will help us to identify new biomarkers and novel therapeutic targets. We harvested six pairs of samples from GC patients and evaluated the differentially expressed proteins using mass spectrometry-based proteomics. RNA sequencing was conducted simultaneously to detect the corresponding expression of mRNAs, and bioinformatics analysis was used to reveal the correlation of significant differentially expressed genes. A total of 57 genes were observed to be dysregulated both in proteomics and transcriptomics. Bioinformatics analysis showed that these differentially expressed genes were significantly associated with regulating metabolic activity. Further, 14 metabolic genes were identified as potential targets for GC patients and were related to immune cell infiltration. Moreover, we found that dysregulation of branched-chain amino acid transaminase 2 (BCAT2), one of the 14 differentially expressed metabolism-related genes, was associated with the overall survival time in GC patients. We believe that this study provides comprehensive information to better understand the mechanism underlying the progression of GC metastasis and explores the potential therapeutic and prognostic metabolism-related targets for GC.
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Branched-chain amino acids (BCAAs) are regulators of protein metabolism. However, elevated levels of BCAAs and their metabolites are linked to insulin resistance. We previously demonstrated that the leucine metabolite, α-ketoisocaproate (KIC), inhibited insulin-stimulated glucose transport in myotubes. Like KIC, inflammatory factors are implicated in the development of insulin resistance. Here, we analyzed the effect of KIC and inflammatory factors (homocysteine [50 µM], TNF-α [10 ng/ml], and interleukin 6 (IL-6) [10 ng/ml]) on myotubes. Although KIC suppressed insulin-stimulated glucose transport, addition of the inflammatory factors did not worsen this effect. Depletion of branched-chain aminotransferase 2, the enzyme that catalyzes the conversion of leucine into KIC, abrogated the effect of KIC and the inflammatory factors. The effect of insulin on AKTS473 and S6K1T389 phosphorylation was not modified by treatments. There were no treatment effects on glycogen synthase phosphorylation. Depletion of E1α subunit of branched-chain α-keto acid dehydrogenase, the enzyme that catalyzes the oxidative decarboxylation of KIC, suppressed insulin-stimulated glucose transport, especially in cells incubated in KIC. Thus, defects in BCAA catabolism are contributory to insulin resistance of glucose transport in myotubes, especially in the presence of KIC. Interventions that increase BCAA catabolism may promote muscle glucose utilization and improve insulin resistance and its sequelae.
Asunto(s)
Aminoácidos de Cadena Ramificada/farmacología , Glucosa/metabolismo , Mediadores de Inflamación/farmacología , Insulina/farmacología , Cetoácidos/farmacología , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , 3-Metil-2-Oxobutanoato Deshidrogenasa (Lipoamida)/genética , 3-Metil-2-Oxobutanoato Deshidrogenasa (Lipoamida)/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Fibras Musculares Esqueléticas/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Fosforilación , Ratas , Transaminasas/genética , Transaminasas/metabolismoRESUMEN
5-Oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) is an arachidonic acid metabolite produced along with leukotrienes via the 5-lipoxygenase pathway. Metabolomics studies have shown that 5-oxo-ETE level is elevated in the serum in acute myocardial infarction (AMI). The actions of 5-oxo-ETE are mediated by the highly selective oxoeicosanoid receptor (OXE-R). Moreover, increased OXE-R content was verified in AMI patients and mice. However, the precise role of OXE-R in AMI is unclear. In the present study, we demonstrate that 5-oxo-ETE triggered myocardial injury in mice. Pathway enrichment analysis identified branched chain amino acid transaminase 1/2 (BCAT1/2) as potential mediators of this effect. Western blot and immunohistochemical analyses showed that BCAT1/BCAT2 expression was significantly reduced by AMI in vitro and in vivo, while pharmacologic inhibition of BCAT1/BCAT2 accelerated myocardial injury. Conversely, heart-specific overexpression of BCAT1/BCAT2 in mice protected against ischemic myocardial injury. Treatment with the selective OXE-R inhibitor Gue1654 alleviated coronary artery ligation-induced ischemic myocardial injury in mice and oxygen/glucose deprivation-induced injury in cardiomyocytes through activation of BCAT1, while inhibiting OXE-R suppressed protein kinase C-ε (PKC-ε)/nuclear factor κB (NF-κB) signaling and cardiomyocyte apoptosis. Overall, our study confirmed a novel target OXE-R for the treatment of AMI based on metabolomics, and targeting OXE-R may represent unrecognized therapeutic intervention for cardiovascular diseases through activation of BCAT1.
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Ácidos Araquidónicos/metabolismo , Bencenoacetamidas/farmacología , Benzotiazoles/farmacología , Infarto del Miocardio/tratamiento farmacológico , Miocitos Cardíacos/efectos de los fármacos , Receptores Eicosanoides/antagonistas & inhibidores , Transaminasas/metabolismo , Anciano , Animales , Apoptosis/efectos de los fármacos , Estudios de Casos y Controles , Línea Celular , Modelos Animales de Enfermedad , Activación Enzimática , Femenino , Humanos , Masculino , Metaboloma , Ratones Endogámicos C57BL , Persona de Mediana Edad , Infarto del Miocardio/enzimología , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/enzimología , Miocitos Cardíacos/ultraestructura , FN-kappa B/metabolismo , Proteína Quinasa C-epsilon/metabolismo , Ratas , Receptores Eicosanoides/metabolismo , Transducción de Señal , Transaminasas/genética , Función Ventricular Izquierda/efectos de los fármacosRESUMEN
Much is known about the positive effects of branched-chain amino acids (BCAA) in regulating muscle protein metabolism. Comparatively much less is known about the effects of these amino acids and their metabolites in regulating myotube formation. Using cultured myoblasts, we showed that although leucine is required for myotube formation, this requirement is easily met by α-ketoisocaproic acid, the ketoacid of leucine. We then demonstrated increases in the expression of the first two enzymes in the catabolism of the three BCAA, branched-chain amino transferase (BCAT2) and branched-chain α-ketoacid dehydrogenase (BCKD), with ~3× increase in BCKD protein expression (p < .05) during differentiation. Furthermore, depletion of BCAT2 abolished myoblast differentiation, as indicated by reduction in the levels of myosin heavy chain-1, troponin and myogenin. Supplementation of incubation medium with branched-chain α-ketoacids or related metabolites derivable from BCAT2 functions did not rescue the defects. However, co-depletion of BCKD kinase partially rescued the defects. Collectively, our data indicate a requirement for BCAA catabolism during myotube formation and that this requirement for BCAT2 likely goes beyond the need for this enzyme to generate the α-ketoacids of the BCAA.
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Diferenciación Celular , Proteínas Mitocondriales/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/metabolismo , Transaminasas/metabolismo , Animales , Línea Celular , Proteínas Mitocondriales/deficiencia , Proteínas Mitocondriales/genética , Fibras Musculares Esqueléticas/citología , Mioblastos/citología , Miogenina/genética , Miogenina/metabolismo , Cadenas Pesadas de Miosina/genética , Cadenas Pesadas de Miosina/metabolismo , Ratas , Transaminasas/deficiencia , Transaminasas/genética , Troponina/genética , Troponina/metabolismoRESUMEN
The first step in branched-chain amino acid (BCAA) catabolism is catalyzed by the two BCAA transferase isoenzymes, cytoplasmic branched-chain amino acid transferase (BCAT) 1, and mitochondrial BCAT2. Defects in the second step of BCAA catabolism cause maple syrup urine disease (MSUD), a condition which has been far more extensively investigated. Here, we studied the consequences of BCAT2 deficiency, an ultra-rare condition in humans. We present genetic, clinical, and functional data in five individuals from four different families with homozygous or compound heterozygous BCAT2 mutations which were all detected following abnormal biochemical profile results or familial mutation segregation studies. We demonstrate that BCAT2 deficiency has a recognizable biochemical profile with raised plasma BCAAs and, in contrast with MSUD, low-normal branched-chain keto acids (BCKAs) with undetectable l-allo-isoleucine. Interestingly, unlike in MSUD, none of the individuals with BCAT2 deficiency developed acute encephalopathy even with exceptionally high BCAA levels. We observed wide-ranging clinical phenotypes in individuals with BCAT2 deficiency. While one adult was apparently asymptomatic, three individuals had presented with developmental delay and autistic features. We show that the biochemical characteristics of BCAT2 deficiency may be amenable to protein-restricted diet and that early treatment may improve outcome in affected individuals. BCAT2 deficiency is an inborn error of BCAA catabolism. At present, it is unclear whether developmental delay and autism are parts of the variable phenotypic spectrum of this condition or coincidental. Further studies will be required to explore this.
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Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Errores Innatos del Metabolismo de los Aminoácidos/genética , Aminoácidos de Cadena Ramificada/sangre , Encéfalo/patología , Mitocondrias/patología , Proteínas Gestacionales/deficiencia , Transaminasas/deficiencia , Adolescente , Adulto , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Femenino , Homocigoto , Humanos , Imagen por Resonancia Magnética , Masculino , Antígenos de Histocompatibilidad Menor/genética , Mutación , Fenotipo , Proteínas Gestacionales/genética , Transaminasas/genéticaRESUMEN
IDH1 mutations are common in low-grade gliomas and secondary glioblastomas and cause overproduction of (R)-2HG. (R)-2HG modulates the activity of many enzymes, including some that are linked to transformation and some that are probably bystanders. Although prior work on (R)-2HG targets focused on 2OG-dependent dioxygenases, we found that (R)-2HG potently inhibits the 2OG-dependent transaminases BCAT1 and BCAT2, likely as a bystander effect, thereby decreasing glutamate levels and increasing dependence on glutaminase for the biosynthesis of glutamate and one of its products, glutathione. Inhibiting glutaminase specifically sensitized IDH mutant glioma cells to oxidative stress in vitro and to radiation in vitro and in vivo. These findings highlight the complementary roles for BCATs and glutaminase in glutamate biosynthesis, explain the sensitivity of IDH mutant cells to glutaminase inhibitors, and suggest a strategy for maximizing the effectiveness of such inhibitors against IDH mutant gliomas.
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Glioma/metabolismo , Ácido Glutámico/biosíntesis , Transaminasas/fisiología , Línea Celular Tumoral , Glioma/fisiopatología , Ácido Glutámico/efectos de los fármacos , Glutaratos/metabolismo , Glutaratos/farmacología , Homeostasis/efectos de los fármacos , Humanos , Isocitrato Deshidrogenasa/genética , Isocitrato Deshidrogenasa/fisiología , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/fisiología , Mutación , Oxidación-Reducción/efectos de los fármacos , Proteínas Gestacionales/genética , Proteínas Gestacionales/fisiología , Transaminasas/antagonistas & inhibidores , Transaminasas/genéticaRESUMEN
Endurance (END)- and resistance (RES)-trained males performed interval running or resistance exercise during three consecutive days (bouts 1-3). Muscle biopsies were obtained at baseline, 2 h post-bout 1, and 72 h post-bout 3. Amino acid transporter SNAT2 mRNA was 75% greater in END (group p = 0.008), and increased ~ 70% 2 h post in both groups (time p = 0.023). Amino acid transporter PAT1 mRNA was 2.7-fold greater in RES (group p = 0.002). Baseline protein levels of the mitochondrial aminotransferase BCAT2 were 79% greater in END (p = 0.015).
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Antígenos de Histocompatibilidad Menor/biosíntesis , Músculo Esquelético/metabolismo , Resistencia Física/fisiología , Proteínas Gestacionales/biosíntesis , Entrenamiento de Fuerza , Carrera/fisiología , Transaminasas/biosíntesis , Adulto , Humanos , Masculino , Factores de TiempoRESUMEN
The differentiation of preadipocytes into adipose tissues is tightly regulated by various factors including microRNAs and cytokines. This article aims to study the effect of miR-330-5p on expression of BCAT2 in ovine preadipocytes. Ovine preadipocytes were isolated, and we found that the miR-330-5p expression decreased gradually during the early differentiation of ovine preadipocytes, while BCAT2 expression increased. BCAT2 was identified as a direct target of miR-330-5p, ectopic expression of miR-330-5p could change the expression of both BCAT2 mRNA and protein. Silencing BCAT2 had the same inhibition effects as overexpressing miR-330-5p on the preadipocyte differentiation, but overexpressing BCAT2 had the converse effects. Taken together, we demonstrated that miR-330-5p is a negative regulator of differentiation by targeting BCAT2, and clarified the role of BCAT2 and miR-330-5p during preadipocyte differentiation.
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Adipocitos/citología , Diferenciación Celular/genética , Regulación del Desarrollo de la Expresión Génica/genética , MicroARNs/genética , Antígenos de Histocompatibilidad Menor/metabolismo , Transaminasas/metabolismo , Tejido Adiposo , Animales , Células Cultivadas , Antígenos de Histocompatibilidad Menor/genética , ARN Mensajero/metabolismo , Ovinos , Transaminasas/genéticaRESUMEN
MicroRNAs are implicated in neuronal development and maturation. Neuronal maturation, including axon outgrowth and dendrite tree formation, is regulated by complex mechanisms and related to several neurodevelopmental disorders. We demonstrated that one neuron-enriched microRNA, microRNA-182 (miR-182), played a significant role in regulating neuronal axon outgrowth and dendrite tree formation. Overexpression of miR-182 promoted axon outgrowth and complexity of the dendrite tree while also increasing the expression of neurofilament-M and neurofilament-L, which provide structural support for neurite outgrowth. However, a reduction of miR-182 inhibited neurite outgrowth. Furthermore, we showed that miR-182 activated the AKT pathway by increasing AKT phosphorylation on S473 and T308 and inhibiting PTEN activity by increasing phosphorylation on S380. Inhibition of AKT activity with the PI3-K inhibitor LY294002 could downregulate AKT and PTEN phosphorylation and suppress axon outgrowth. In addition, we showed that BCAT2 might be the target of miR-182 that takes part in the regulation of neuronal maturation; blockage of endogenous BCAT2 promotes axon outgrowth and AKT activity. These observations indicate that miR-182 regulates axon outgrowth and dendrite maturation involving activation of the PTEN/AKT pathway.
RESUMEN
Novel proteoforms with single amino acid variations represent proteins that often have altered biological functions but are less explored in the human proteome. We have developed an approach, searching high quality shotgun proteomic data against an extended protein database, to identify expressed mutant proteoforms in glioma stem cell (GSC) lines. The systematic search of MS/MS spectra using PEAKS 7.0 as the search engine has recognized 17 chromosome 19 proteins in GSCs with altered amino acid sequences. The results were further verified by manual spectral examination, validating 19 proteoforms. One of the novel findings, a mutant form of branched-chain aminotransferase 2 (p.Thr186Arg), was verified at the transcript level and by targeted proteomics in several glioma stem cell lines. The structure of this proteoform was examined by molecular modeling in order to estimate conformational changes due to mutation that might lead to functional modifications potentially linked to glioma. Based on our initial findings, we believe that our approach presented could contribute to construct a more complete map of the human functional proteome.
Asunto(s)
Aminoácidos/química , Neoplasias Encefálicas/química , Cromosomas Humanos Par 19 , Glioma/química , Proteínas de Neoplasias/química , Células Madre Neoplásicas/química , Secuencia de Aminoácidos , Humanos , Datos de Secuencia Molecular , TranscriptomaRESUMEN
Liver transplantation appears to be quite beneficial for treatment of maple syrup urine disease (MSUD, an inherited disorder of branched chain amino acid metabolism); however, there is a limited availability of donor livers worldwide and the first year costs of liver transplants are quite high. Recent studies have suggested that intact adipose tissue, already widely used in reconstructive surgery, may have an underappreciated high capacity for branched chain amino acid (BCAA) metabolism. Here we examined the potential for adipose tissue transplant to lower circulating BCAAs in two models of defective BCAA metabolism, BCATm and PP2Cm [branched chain keto acid dehydrogenase complex (BCKDC) phosphatase] knockout (KO) mice. After 1-2g fat transplant, BCATm and PP2Cm KO mice gained or maintained body weight 3weeks after surgery and consumed similar or more food/BCAAs the week before phlebotomy. Transplant of fat into the abdominal cavity led to a sterile inflammatory response and nonviable transplanted tissue. However when 1-2g of fat was transplanted subcutaneously into the back, either as small (0.1-0.3g) or finely minced pieces introduced with an 18-ga. needle, plasma BCAAs decreased compared to Sham operated mice. In two studies on BCATm KO mice and one study on PP2Cm KO mice, fat transplant led to 52-81% reductions in plasma BCAAs compared to baseline plasma BCAA concentrations of untreated WT type siblings. In PP2Cm KO mice, individual BCAAs in plasma were also significantly reduced by fat transplant, as were the alloisoleucine/Phe ratios. Therefore, subcutaneous fat transplantation may have merit as an adjunct to dietary treatment of MSUD. Additional studies are needed to further refine this approach.