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1.
Molecules ; 24(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31500110

RESUMO

Carnitine plays essential roles in intermediary metabolism. In non-vegetarians, most of carnitine sources (~75%) are obtained from diet whereas endogenous synthesis accounts for around 25%. Renal carnitine reabsorption along with dietary intake and endogenous production maintain carnitine homeostasis. The precursors for carnitine biosynthesis are lysine and methionine. The biosynthetic pathway involves four enzymes: 6-N-trimethyllysine dioxygenase (TMLD), 3-hydroxy-6-N-trimethyllysine aldolase (HTMLA), 4-N-trimethylaminobutyraldehyde dehydrogenase (TMABADH), and γ-butyrobetaine dioxygenase (BBD). OCTN2 (organic cation/carnitine transporter novel type 2) transports carnitine into the cells. One of the major functions of carnitine is shuttling long-chain fatty acids across the mitochondrial membrane from the cytosol into the mitochondrial matrix for ß-oxidation. This transport is achieved by mitochondrial carnitine-acylcarnitine cycle, which consists of three enzymes: carnitine palmitoyltransferase I (CPT I), carnitine-acylcarnitine translocase (CACT), and carnitine palmitoyltransferase II (CPT II). Carnitine inborn errors of metabolism could result from defects in carnitine biosynthesis, carnitine transport, or mitochondrial carnitine-acylcarnitine cycle. The presentation of these disorders is variable but common findings include hypoketotic hypoglycemia, cardio(myopathy), and liver disease. In this review, the metabolism and homeostasis of carnitine are discussed. Then we present details of different inborn errors of carnitine metabolism, including clinical presentation, diagnosis, and treatment options. At the end, we discuss some of the causes of secondary carnitine deficiency.


Assuntos
Cardiomiopatias/genética , Carnitina/deficiência , Carnitina/genética , Hiperamonemia/genética , Erros Inatos do Metabolismo/genética , Mitocôndrias/enzimologia , Doenças Musculares/genética , Aldeído Oxirredutases/genética , Cardiomiopatias/metabolismo , Carnitina/biossíntese , Carnitina/metabolismo , Carnitina Aciltransferases/genética , Carnitina O-Palmitoiltransferase/genética , Humanos , Hiperamonemia/metabolismo , Mitocôndrias/genética , Oxigenases de Função Mista/genética , Doenças Musculares/metabolismo , Oxirredução , Membro 5 da Família 22 de Carreadores de Soluto/genética , gama-Butirobetaína Dioxigenase/genética
2.
Biochim Biophys Acta Bioenerg ; 1860(9): 708-716, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31340138

RESUMO

The mitochondrial carnitine/acylcarnitine carrier (CACT) catalyzes an antiport of carnitine and acylcarnitines and also a uniport reaction with a rate of about one tenth with respect to the antiport rate. The antiport process results from the coupling of the two uniport reactions in opposite directions. In this mechanism, the transition of the carrier from the outward open conformation to the inward open one (or vice versa) is much faster for the carrier-substrate complex than for the unbound carrier. To investigate the molecular determinants that couple the binding of the substrate with the conformational transitions, site directed mutagenesis has been employed. The antiport or the uniport reaction was followed as [3H]carnitine uptake in or efflux from proteoliposomes reconstituted with the WT or Trp mutants of the rat CACT. Substitution of each the three Trp residues led to different results. Nearly no variations were observed upon substitution of W192 and/or W296 with Ala. While, substantial alteration of the transport function was observed in the mutants W224A, W224Y and W224F. Mutation of W224 led to the loss of the antiport function while the uniport function was unaltered. In these mutants impairment of the substrate affinity on the external side was also observed. The data highlights that W224 is involved in the coupling of the substrate binding with the matrix gate opening. The experimental data are in line with predictions by homology modeling of the CACT in its cytosolic (c-state) or matrix (m-state) opened conformations.


Assuntos
Antiporters/metabolismo , Carnitina Aciltransferases/metabolismo , Carnitina/análogos & derivados , Carnitina/metabolismo , Triptofano/metabolismo , Sequência de Aminoácidos , Animais , Aspergillus nidulans , Transporte Biológico , Carnitina Aciltransferases/química , Carnitina Aciltransferases/genética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação , Conformação Proteica , Ratos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência , Triptofano/química , Triptofano/genética
3.
Cells ; 8(7)2019 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295943

RESUMO

Aberrant activation of signaling pathways is frequently observed and reported to be associated with the progression and poor prognosis of prostate cancer (PCa). We aimed to identify key biological processes regulated by androgen receptor (AR) using gene co-expression network from single cell resolution. The bimodal index was used to evaluate whether two subpopulations exist among the single cells. Gene expression among single cells revealed averaging pitfalls and bimodality pattern. Weighted gene co-expression network analysis (WGCNA) was used to identify modules of highly correlated genes. Twenty-nine gene modules were identified and AR-regulated modules were screened by significantly overlapping reported androgen induced differentially expressed genes. The biological function "generation of precursor metabolites and energy" was significantly enriched by AR-regulated modules with bimodality, presenting differential androgen response among subpopulations. Integrating with public ChIP-seq data, two genes FECH, and CROT has AR binding sites. Public in vitro studies also show that androgen regulates FECH and CROT. After receiving androgen deprivation therapy, patients lowly express FECH and CROT. Further survival analysis indicates that FECH/CROT signature can predict PCa recurrence. We reveal the heterogeneous function of "generation of precursor metabolites and energy" upon androgen stimulation from the perspective of single cells. Inhibitors targeting this biological process will facilitate to prevent prostate cancer progression.


Assuntos
Carnitina Aciltransferases/genética , Ferroquelatase/genética , Neoplasias da Próstata/genética , Antagonistas de Androgênios , Androgênios , Carnitina Aciltransferases/metabolismo , Linhagem Celular Tumoral , Bases de Dados Genéticas , Ferroquelatase/metabolismo , Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/genética , Redes Reguladoras de Genes/genética , Humanos , Masculino , Recidiva Local de Neoplasia/genética , Prognóstico , Receptores Androgênicos/biossíntese , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Transdução de Sinais/genética , Análise de Célula Única/métodos , Transcriptoma/genética
4.
Biomed Pharmacother ; 118: 109130, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306969

RESUMO

OBJECTIVES: The objective of this work was to determine the specific mechanisms by which resveratrol inhibits lipogenesis and stimulates lipolysis. METHODS: Twelve male mice were individually introduced into a metabolic cage for 24 h to measure basal metabolic rate, prior to intervention. They were randomly divided into two groups, resveratrol (RSV) and control (C), and administered resveratrol intraperitoneally or vehicle, respectively, for two consecutive days. After 24 h, the metabolic energy expenditure was again determined for 24 h, before mice were sacrificed. Protein and gene expression of different enzymes related to metabolism in the hepatic tissue, adipose tissue and gastrocnemius of mice were analyzed by RT-PCR, western blot or ELISA. RESULTS: We report that resveratrol lowers the respiratory quotient in old mice and that this may be due to the activation of fatty acid mobilization from white adipose tissue (because hormone-activated lipase expression is increased) and fatty acid transport into mitochondria and eventual oxidation in muscle and liver (because transport enzymes and beta oxidation enzymes are also increased). Indeed, we have observed that resveratrol in vivo causes an increase in the expression and phosphorylation of AMPKα in liver, muscle and adipose tissue and an increase in the expression of acyl-CoA synthetase, of carnitine palmitoyl transferase 1 and of carnitine acylcarnitine translocase, all enzymes involved in lipid catabolism. On the other hand, the levels of acetyl-CoA carboxylase as well as those its product, i.e. malonyl CoA, are decreased. CONCLUSIONS: We conclude that a controlled dose of resveratrol activates fatty acid mobilization and degradation and inhibits fatty acid synthesis in old mice. This is the first time that these effects of resveratrol in lipid metabolism in healthy old (non-obese) animals are reported.


Assuntos
Envelhecimento/metabolismo , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/metabolismo , Lipogênese/efeitos dos fármacos , Lipólise/efeitos dos fármacos , Resveratrol/farmacologia , Acetil-CoA Carboxilase/genética , Acetil-CoA Carboxilase/metabolismo , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Envelhecimento/genética , Animais , Carnitina Aciltransferases/genética , Carnitina Aciltransferases/metabolismo , Metabolismo Energético/genética , Lipogênese/genética , Lipólise/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxirredução
5.
Chem Biol Interact ; 307: 179-185, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31063765

RESUMO

The effect of polyphenols, recognized as the principal antioxidant and beneficial molecules introduced with the diet, extracted from sweet cherry (Prunus avium L.) on the recombinant human mitochondrial carnitine/acylcarnitine transporter (CACT) has been studied in proteoliposomes. CACT transport activity, which was strongly impaired after oxidation by atmospheric O2 or H2O2, due to the formation of a disulfide bridge between cysteines 136 and 155, was restored by externally added polyphenols. CACT reduction by polyphenols was time dependent. Spectroscopic analysis of polyphenolic extracts revealed eight most represented compounds in four cultivars. Molecular docking of CACT structural omology model with the most either abundant and arguably bio-available phenolic compound (trans 3-O-feruloyl-quinic acid) of the mix, is in agreement with the experimental data since it results located in the active site close to cysteine 136 at the bottom of the translocation aqueous cavity.


Assuntos
Carnitina Aciltransferases/metabolismo , Mitocôndrias/metabolismo , Polifenóis/metabolismo , Prunus avium/química , Sítios de Ligação , Carnitina Aciltransferases/química , Carnitina Aciltransferases/genética , Humanos , Peróxido de Hidrogênio/química , Simulação de Acoplamento Molecular , Mutagênese Sítio-Dirigida , Oxirredução , Polifenóis/análise , Estrutura Terciária de Proteína , Prunus avium/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray
6.
Clin Chim Acta ; 495: 476-480, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31108048

RESUMO

Carnitine-acylcarnitine translocase deficiency (CACTD) is a rare autosomal recessive disorder of mitochondrial fatty acid oxidation that occurs due to mutations in the SLC25A20 gene. Severe CACTD results in neonatal or infantile sudden death. Herein, we reported six patients with CACTD diagnosed based on biochemical and molecular findings from 5 unrelated families in Guangdong from 2016 to 2017. Among them, five patients presented with hypotonia, nonketotic hypoglycemia, and arrhythmia 2 days after birth, while the other patient presented with respiratory distress, hypotonia, and arrhythmia. Five of the patients died in the neonatal period. Blood acylcarnitine concentrations determination from dried blood spots (DBS) were measured by tandem mass spectrometry (MS/MS). The SLC25A20 and CPT2 gene sequences were analyzed by direct Sanger sequencing. SLC25A20 gene analysis revealed a c.199-10T>G (IVS2-10T>G) homozygous variants in four unrelated patients and a novel mutation c.199-10T>G/c.719-8_c.719-1dupCCCACAG compound heterozygous variants in twins. This report describes the clinical characteristics, biochemical findings and molecular analysis of SLC25A20 gene of patients with CACTD in Guangdong. And our results show that the c.199-10T>G is likely the most common variant of CACTD in Guangdong population as it accounts for 83% (10/12) of the observed mutant alleles. Individuals with the c.199-10T>G genotype had a severe CACTD phenotype.


Assuntos
Carnitina Aciltransferases/deficiência , Erros Inatos do Metabolismo Lipídico/diagnóstico , Erros Inatos do Metabolismo Lipídico/genética , Proteínas de Transporte de Ânions/genética , Carnitina Aciltransferases/genética , China , Feminino , Genótipo , Humanos , Recém-Nascido , Masculino , Proteínas Mitocondriais/genética , Triagem Neonatal , Linhagem , Análise de Sequência de DNA
7.
Environ Sci Pollut Res Int ; 25(32): 32506-32514, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30238259

RESUMO

Benzene is an environmental and occupational contaminant. Health hazards associated with occupational benzene exposure is a major public health problem in China. In this study, we analyzed metabolite profiles among plasma samples collected from benzene-exposed workers with low white blood cell count (BLWs) and healthy controls using high-performance liquid chromatography-time-of-flight mass spectrometry. To screen potential benzene hematotoxicity biomarkers and metabolic pathways, principal component analysis was used to examine metabolite profile changes in plasma samples. The alterations in fatty acid oxidation (FAO) pathway were consistent with our previous findings in a mouse model; hence, two key genes were selected and verified in WBC samples. A total of nine identified metabolites were significantly changed in BLWs, which were involved in glutathione metabolism, porphyrin metabolism, lipid metabolism pathway, and FAO metabolism. Furthermore, compared with healthy controls, the mRNA expressions of carnitine acyltransferase (CRAT) and ACADVL were significantly increased in BLWs. Particularly, WBC counts was negatively correlated with the expression of AVADVL in BLWs. These aberrant metabolites could act as potential biomarkers for benzene hematotoxicity. In addition, fatty acid oxidation pathway may play a critical role in the development of hematotoxicity caused by benzene.


Assuntos
Benzeno/toxicidade , Ácidos Graxos/sangue , Contagem de Leucócitos , Exposição Ocupacional/efeitos adversos , Acil-CoA Desidrogenase de Cadeia Longa/sangue , Acil-CoA Desidrogenase de Cadeia Longa/deficiência , Adulto , Animais , Grupo com Ancestrais do Continente Asiático , Biomarcadores/sangue , Carnitina Aciltransferases/sangue , China , Síndrome Congênita de Insuficiência da Medula Óssea , Feminino , Glutationa/sangue , Hemolíticos , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Erros Inatos do Metabolismo Lipídico/sangue , Masculino , Espectrometria de Massas , Metaboloma , Metabolômica/métodos , Camundongos , Doenças Mitocondriais/sangue , Doenças Musculares/sangue , Exposição Ocupacional/análise , Oxirredução , Porfirinas/sangue , RNA Mensageiro/metabolismo
8.
Biosens Bioelectron ; 119: 48-54, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30098466

RESUMO

A CMOS-compatible ISFET with a Ta2O5 sensitive surface was developed. The structure was optimized for achieving high sensitivity using a subthreshold operation mode and by reducing the influence of the capacitances on the value of subthreshold swing. The developed ISFET was used as a basis for a biosensor for L-carnitine detection. To this end, carnitine acetyltransferase was immobilized on the ISFET sensitive surface. The immobilized enzyme was active (0.082 U/g model plate). The complete microsystem, consisting of a packaged chip, an immobilized enzyme and a microfluidic channel, detected L-carnitine at a range of 0.2-100 µM with a LOD of 0.2 µM. The biosensor response was linear in the range of 0.2-50 µM of L-carnitine with sensitivity 18.0 ±â€¯1.7 mV/µM. An experiment with artificial urine containing 1.3 µM L-carnitine showed that the proposed biosensor could be used on a real sample. Therefore, a new sensor specially optimized for biosensing CMOS-compatible ISFET structures and direct determination of L-carnitine with immobilized carnitine acetyltransferase was developed.


Assuntos
Técnicas Biossensoriais/métodos , Carnitina/urina , Enzimas Imobilizadas/metabolismo , Microfluídica , Urinálise/métodos , Carnitina Aciltransferases/metabolismo , Capacitância Elétrica , Humanos , Limite de Detecção , Urinálise/instrumentação
9.
Plant Sci ; 274: 432-440, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30080631

RESUMO

L-carnitine is present in all living kingdoms where it acts in diverse physiological processes. It is involved in lipid metabolism in animals and yeasts, notably as an essential cofactor of fatty acid intracellular trafficking. Its physiological significance is poorly understood in plants, but L-carnitine may be linked to fatty acid metabolism among other roles. Indeed, carnitine transferases activities and acylcarnitines are measured in plant tissues. Current knowledge of fatty acid trafficking in plants rules out acylcarnitines as intermediates of the peroxisomal and mitochondrial fatty acid metabolism, unlike in animals and yeasts. Instead, acylcarnitines could be involved in plastidial exportation of de novo fatty acid, or importation of fatty acids into the ER, for synthesis of specific glycerolipids. L-carnitine also contributes to cellular maintenance though antioxidant and osmolyte properties in animals and microbes. Recent data indicate similar features in plants, together with modulation of signaling pathways. The biosynthesis of L-carnitine in the plant cell shares similar precursors as in the animal and yeast cells. The elucidation of the biosynthesis pathway of L-carnitine, and the identification of the enzymes involved, is today essential to progress further in the comprehension of its biological significance in plants.


Assuntos
Carnitina Aciltransferases/metabolismo , Carnitina/análogos & derivados , Carnitina/fisiologia , Ácidos Graxos/fisiologia , Plantas/metabolismo , Animais , Carnitina Aciltransferases/genética , Metabolismo dos Lipídeos , Mitocôndrias/metabolismo
10.
Zhonghua Er Ke Za Zhi ; 56(7): 545-549, 2018 Jul 02.
Artigo em Chinês | MEDLINE | ID: mdl-29996190

RESUMO

Objective: To investigate the clinical, biochemical and genetic features of four carnitine-acylcarnitine translocase deficiency cases. Methods: Four cases diagnosed with carnitine-acylcarnitine translocase deficiency from Guangxi Maternal and Child Health Hospital were studied. DNA was extracted from dry blood filter for gene analysis. SLC25A20 gene analysis was performed in 1 case and the whole exon sequence analysis was performed in 3 cases. Results: Retrospective study on unrelated carnitine-acylcarnitine translocase deficiency patients, the age of onset was 1-28 d, the age of death were 1.5-30 d, main clinical features were hypoglycemia (4 cases), arrhythmia (2 cases), sudden death (2 cases). Biochemical test showed hypoglycemia (1.2-2.0 mmol/L) , elevated creatine kinase (955-8 361 U/L) and creatine kinase isozyme(199-360 U/L), normal or decreased free carnitine level (3.70-27.07 µmol/L) , elevated long-chain acylcarnitine (palmityl carnitine 1.85-14.84 µmol/L). The gene tests showed that all 4 cases carried SLC25A20 gene c.199-10T> G homozygous mutation, inherited from their parents. By analyzing the haplotype, we found that the mutation loci of C. 199-10T> G were all in the same haplotype. Conclusion: The c.199-10T> G mutation is an important molecular cause of carnitine-acylcarnitine translocase deficiency, which has relatively high frequency in Guangxi population, and is related to the founder effect.


Assuntos
Carnitina Aciltransferases/deficiência , Erros Inatos do Metabolismo Lipídico , Proteínas de Membrana Transportadoras , Mutação , Carnitina , Carnitina Aciltransferases/genética , China , Efeito Fundador , Humanos , Lactente , Recém-Nascido , Erros Inatos do Metabolismo Lipídico/complicações , Erros Inatos do Metabolismo Lipídico/genética , Proteínas de Membrana Transportadoras/genética , Estudos Retrospectivos
11.
Oncogene ; 37(19): 2545-2558, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29459713

RESUMO

Warburg effect has been recognized as a hallmark of cancer cells for many years, but its modulation mechanism remains a great focus. Our current study found a member of solute carrier family 25 (SLC25A29), the main arginine transporter on mitochondria, significantly elevated in various cancer cells. Knockout of SLC25A29 by CRISPR/Cas9 inhibited proliferation and migration of cancer cells both in vitro and in vivo. SLC25A29-knockout cells also showed an altered metabolic status with enhanced mitochondrial respiration and reduced glycolysis. All of above impacts could be reversed after rescuing SLC25A29 expression in SLC25A29-knockout cells. Arginine is transported into mitochondria partly for nitric oxide (NO) synthesis. Deletion of SLC25A29 resulted in severe decrease of NO production, indicating that the mitochondria is a significant source of NO. SLC25A29-knockout cells dramatically altered the variation of metabolic processes, whereas addition of arginine failed to reverse the effect, highlighting the necessity of transporting arginine into mitochondria by SLC25A29. In conclusion, aberrant elevated SLC25A29 in cancer functioned to transport more arginine into mitochondria, improved mitochondria-derived NO levels, thus modulated metabolic status to facilitate increased cancer progression.


Assuntos
Carnitina Aciltransferases/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Neoplasias/metabolismo , Óxido Nítrico/metabolismo , Regulação para Cima , Animais , Arginina/metabolismo , Carnitina Aciltransferases/metabolismo , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Técnicas de Inativação de Genes , Glicólise , Células HeLa , Células Hep G2 , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Proteínas Mitocondriais/metabolismo , Transplante de Neoplasias , Neoplasias/genética , Neoplasias/patologia
12.
Cell Death Dis ; 9(2): 228, 2018 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-29445084

RESUMO

Metabolic flexibility describes the ability of cells to respond or adapt its metabolism to support and enable rapid proliferation, continuous growth, and survival in hostile conditions. This dynamic character of the cellular metabolic network appears enhanced in cancer cells, in order to increase the adaptive phenotype and to maintain both viability and uncontrolled proliferation. Cancer cells can reprogram their metabolism to satisfy the energy as well as the biosynthetic intermediate request and to preserve their integrity from the harsh and hypoxic environment. Although several studies now recognize these reprogrammed activities as hallmarks of cancer, it remains unclear which are the pathways involved in regulating metabolic plasticity. Recent findings have suggested that carnitine system (CS) could be considered as a gridlock to finely trigger the metabolic flexibility of cancer cells. Indeed, the components of this system are involved in the bi-directional transport of acyl moieties from cytosol to mitochondria and vice versa, thus playing a fundamental role in tuning the switch between the glucose and fatty acid metabolism. Therefore, the CS regulation, at both enzymatic and epigenetic levels, plays a pivotal role in tumors, suggesting new druggable pathways for prevention and treatment of human cancer.


Assuntos
Carnitina/metabolismo , Epigênese Genética , Ácidos Graxos/metabolismo , Glucose/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Transporte Biológico , Carnitina Aciltransferases/genética , Carnitina Aciltransferases/metabolismo , Carnitina O-Palmitoiltransferase/genética , Carnitina O-Palmitoiltransferase/metabolismo , Metabolismo Energético/genética , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Metabolismo dos Lipídeos , MicroRNAs/genética , MicroRNAs/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patologia , Transdução de Sinais , Células Tumorais Cultivadas
13.
J Pediatr Endocrinol Metab ; 31(3): 297-304, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29425111

RESUMO

BACKGROUND: Children with long-chain fatty acid ß-oxidation disorders (LCFAOD) presenting with clinical symptoms are treated with a specialist infant formula, with medium chain triglyceride (MCT) mainly replacing long chain triglyceride (LCT). It is essential that the safety and efficacy of any new specialist formula designed for LCFAOD be tested in infants and children. METHODS: In an open-label, 21-day, phase I trial, we studied the safety of a new MCT-based formula (feed 1) in six well-controlled children (three male), aged 7-13 years (median 9 years) with LCFAOD (very long chain acyl CoA dehydrogenase deficiency [VLCADD], n=2; long chain 3-hydroxyacyl CoA dehydrogenase deficiency [LCHADD], n=2; carnitine acyl carnitine translocase deficiency [CACTD], n=2). Feed 1 (Lipistart; Vitaflo) contained 30% energy from MCT, 7.5% LCT and 3% linoleic acid and it was compared with a conventional MCT feed (Monogen; Nutricia) (feed 2) containing 17% energy from MCT, 3% LCT and 1.1% linoleic acid. Subjects consumed feed 2 for 7 days then feed 1 for 7 days and finally resumed feed 2 for 7 days. Vital signs, blood biochemistry, ECG, weight, height, food/feed intake and symptoms were monitored. RESULTS: Five subjects completed the study. Their median daily volume of both feeds was 720 mL (range 500-1900 mL/day). Feed 1 was associated with minimal changes in tolerance, free fatty acids (FFA), acylcarnitines, 3-hydroxybutyrate (3-HB), creatine kinase (CK), blood glucose, liver enzymes and no change in an electrocardiogram (ECG). No child complained of muscle pain or symptoms associated with LCFAOD on either feed. CONCLUSIONS: This is the first safety trial reported of an MCT formula specifically designed for infants and children with LCFAOD. In this short-term study, it appeared safe and well tolerated in this challenging group.


Assuntos
3-Hidroxiacil-CoA Desidrogenases/deficiência , Acil-CoA Desidrogenase de Cadeia Longa/deficiência , Carnitina Aciltransferases/deficiência , Erros Inatos do Metabolismo Lipídico/dietoterapia , Doenças Mitocondriais/dietoterapia , Doenças Musculares/dietoterapia , Triglicerídeos/administração & dosagem , Adolescente , Criança , Síndrome Congênita de Insuficiência da Medula Óssea , Feminino , Humanos , Masculino , Triglicerídeos/efeitos adversos
14.
Trends Endocrinol Metab ; 29(1): 18-30, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29221849

RESUMO

This review summarizes how fatty acid (FA) oxidation is regulated in skeletal muscle during exercise. From the available evidence it seems that acetyl-CoA availability in the mitochondrial matrix adjusts FA oxidation to exercise intensity and duration. This is executed at the step of mitochondrial fatty acyl import, as the extent of acetyl group sequestration by carnitine determines the availability of carnitine for the carnitine palmitoyltransferase 1 (CPT1) reaction. The rate of glycolysis seems therefore to be central to the amount of ß-oxidation-derived acetyl-CoA that is oxidized in the tricarboxylic acid (TCA) cycle. FA oxidation during exercise is also determined by FA availability to mitochondria, dependent on trans-sarcolemmal FA uptake via cluster of differentiation 36/SR-B2 (CD36) and FAs mobilized from myocellular lipid droplets.


Assuntos
Acetilcoenzima A/metabolismo , Carnitina Aciltransferases/metabolismo , Carnitina/metabolismo , Exercício Físico/fisiologia , Ácidos Graxos/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Animais , Humanos
15.
Medicine (Baltimore) ; 96(45): e8549, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29137068

RESUMO

RATIONALE: Carnitine-acylcarnitine translocate deficiency (CACTD) is a rare and life-threatening, autosomal recessive disorder of fatty acid ß-oxidation characterized by hypoketotic hypoglycemia, hyperammonemia, cardiomyopathy, liver dysfunction, and muscle weakness; culminating in early death. To date, CACTD cases screened from the Chinese mainland population, especially patient with compound heterozygote with c.199-10T>G and a novel c.1A>G mutation in the SLC25A20 gene has never been described. PATIENT CONCERNS: Herein, we report 2 neonatal cases of CACTD identified from the mainland China. These 2 patients were presented with severe metabolic crisis and their clinical conditions deteriorate rapidly and both died of cardiorespiratory collapse in the first week of life. We present the clinical and biochemical features of 2 probands and a brief literature review of previously reported CACTD cases with the c.199-10T>G mutation. DIAGNOSES: The acylcarnitine profiles by tandem-mass-spectrometry and the mutation analysis of SLC25A20 gene confirmed the diagnosis of CACTD in both patients. Mutation analysis demonstrated that patient No. 1 was homozygous for c.199-10T>G mutation, while patient No. 2 was a compound heterozygote for 2 mutations, a maternally-inherited c.199-10T>G and a paternally-inherited, novel c.1A>G mutation. INTERVENTIONS: Both patients were treated with an aggressive treatment regimen include high glucose and arginine infusion, respiratory, and circulatory support. OUTCOMES: The first proband died 3 days after delivery due to sudden cardiac arrest. The second patient's clinical condition, at one time, was improved by high glucose infusion, intravenous arginine, and circulatory support. However, the patient failed to wean from mechanical ventilation. Unfortunately, her parents refused further treatment due to fear of financial burdens. The patient died of congestive heart failure in the 6th day of life. LESSONS: We report the first 2 cases of CACTD identified from the mainland China. Apart from a founder mutation c.199-10T>G, we identified a novel c.1A>G mutation. Patients with CACTD with a genotype of c.199-10T>G mutation usually presents with a severe clinical phenotype. Early recognition and appropriate treatment is crucial in this highly lethal disorder. This case series highlights the importance of screening for metabolic diseases including CACTD in cases of sudden infant death and unexplained abrupt clinical deterioration in the early neonatal period.


Assuntos
Carnitina Aciltransferases/deficiência , Efeito Fundador , Erros Inatos do Metabolismo Lipídico/genética , Proteínas de Membrana Transportadoras/genética , Mutação , Carnitina Aciltransferases/genética , China , Análise Mutacional de DNA , Evolução Fatal , Feminino , Genótipo , Humanos , Recém-Nascido , Masculino
16.
Angew Chem Int Ed Engl ; 56(32): 9556-9560, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28679030

RESUMO

Fungal polyketides have significant biological activities, yet the biosynthesis by highly reducing polyketide synthases (HRPKSs) remains enigmatic. An uncharacterized group of HRPKSs was found to contain a C-terminal domain with significant homology to carnitine O-acyltransferase (cAT). Characterization of one such HRPKS (Tv6-931) from Trichoderma virens showed that the cAT domain is capable of esterifying the polyketide product with polyalcohol nucleophiles. This process is readily reversible, as confirmed through the holo ACP-dependent transesterification of the released product. The methyltransferase (MT) domain of Tv6-931 can perform two consecutive α-methylation steps on the last ß-keto intermediate to yield an α,α-gem-dimethyl product, a new programing feature among HRPKSs. Recapturing of the released product by cAT domain is suggested to facilitate complete gem-dimethylation by the MT.


Assuntos
Carnitina Aciltransferases/metabolismo , Policetídeo Sintases/metabolismo , Trichoderma/enzimologia , Biocatálise , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Domínio Catalítico , Metabolômica , Estrutura Molecular
17.
IUBMB Life ; 69(8): 578-594, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28653367

RESUMO

Carnitine acyltransferases catalyze the reversible transfer of acyl groups from acyl-coenzyme A esters to l-carnitine, forming acyl-carnitine esters that may be transported across cell membranes. l-Carnitine is a wáter-soluble compound that humans may obtain both by food ingestion and endogenous synthesis from trimethyl-lysine. Most l-carnitine is intracellular, being present predominantly in liver, skeletal muscle, heart and kidney. The organic cation transporter-2 facilitates l-carnitine uptake inside cells. Congenital dysfunction of this transporter causes primary l-carnitine deficiency. Carnitine acetyltransferase is involved in the export of excess acetyl groups from the mitochondria and in acetylation reactions that regulate gene transcription and enzyme activity. Carnitine octanoyltransferase is a peroxysomal enzyme required for the complete oxidation of very long-chain fatty acids and phytanic acid, a branched-chain fatty acid. Carnitine palmitoyltransferase-1 is a transmembrane protein located on the outer mitochondrial membrane where it catalyzes the conversion of acyl-coenzyme A esters to acyl-carnitine esters. Carnitine acyl-carnitine translocase transports acyl-carnitine esters across the inner mitochondrial membrane in exchange for free l-carnitine that exits the mitochondrial matrix. Carnitine palmitoyltransferase-2 is anchored on the matrix side of the inner mitochondrial membrane, where it converts acyl-carnitine esters back to acyl-coenzyme A esters, which may be used in metabolic pathways, such as mitochondrial ß-oxidation. l-Carnitine enhances nonoxidative glucose disposal under euglycemic hyperinsulinemic conditions in both healthy individuals and patients with type 2 diabetes, suggesting that l-carnitine strengthens insulin effect on glycogen storage. The plasma level of acyl-carnitine esters, primarily acetyl-carnitine, increases during diabetic ketoacidosis, fasting, and physical activity, particularly high-intensity exercise. Plasma concentration of free l-carnitine decreases simultaneously under these conditions. © 2017 IUBMB Life, 69(8):578-594, 2017.


Assuntos
Cardiomiopatias/genética , Carnitina/deficiência , Carnitina/metabolismo , Hiperamonemia/genética , Fígado/enzimologia , Doenças Musculares/genética , Membro 5 da Família 22 de Carreadores de Soluto/genética , Cardiomiopatias/metabolismo , Carnitina/genética , Carnitina Aciltransferases/genética , Ácidos Graxos/metabolismo , Humanos , Hiperamonemia/metabolismo , Fígado/metabolismo , Mitocôndrias/enzimologia , Mitocôndrias/genética , Doenças Musculares/metabolismo , Oxirredução , Membro 5 da Família 22 de Carreadores de Soluto/metabolismo
18.
Biochim Biophys Acta Bioenerg ; 1858(7): 475-482, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28438511

RESUMO

S-nitrosylation of the mitochondrial carnitine/acylcarnitine transporter (CACT) has been investigated on the native and the recombinant proteins reconstituted in proteoliposomes, and on intact mitochondria. The widely-used NO-releasing compound, GSNO, strongly inhibited the antiport measured in proteoliposomes reconstituted with the native CACT from rat liver mitochondria or the recombinant rat CACT over-expressed in E. coli. Inhibition was reversed by the reducing agent dithioerythritol, indicating a reaction mechanism based on nitrosylation of Cys residues of the CACT. The half inhibition constant (IC50) was very similar for the native and recombinant proteins, i.e., 74 and 71µM, respectively. The inhibition resulted to be competitive with respect the substrate, carnitine. NO competed also with NEM, correlating well with previous data showing interference of NEM with the substrate transport path. Using a site-directed mutagenesis approach on Cys residues of the recombinant CACT, the target of NO was identified. C136 plays a major role in the reaction mechanism. The occurrence of S-nitrosylation was demonstrated in intact mitochondria after treatment with GSNO, immunoprecipitation and immunostaining of CACT with a specific anti NO-Cys antibody. In parallel samples, transport activity of CACT measured in intact mitochondria, was strongly inhibited after GSNO treatment. The possible physiological and pathological implications of the post-translational modification of CACT are discussed.


Assuntos
Carnitina Aciltransferases/antagonistas & inibidores , Cisteína/química , Mitocôndrias/metabolismo , Óxido Nítrico/farmacologia , Processamento de Proteína Pós-Traducional , Sequência de Aminoácidos , Animais , Transporte Biológico , Carnitina/análogos & derivados , Carnitina/metabolismo , Carnitina Aciltransferases/química , Carnitina Aciltransferases/genética , Carnitina Aciltransferases/metabolismo , Sequência Conservada , Ditioeritritol/farmacologia , Lipossomos , Mitocôndrias/efeitos dos fármacos , Modelos Moleculares , Doadores de Óxido Nítrico/farmacologia , Nitrogênio , Oxirredução , Conformação Proteica , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Ratos , S-Nitrosoglutationa/farmacologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
19.
Eur J Nutr ; 56(7): 2309-2318, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27444711

RESUMO

PURPOSE: To investigate the mechanistic effects of combined exposure to caffeine and catechins on lipid metabolism in mice. METHODS: Seventy mice were randomly assigned to seven groups and fed diets containing varying doses of caffeine and catechins for 24 weeks. Body weight gain, intraperitoneal adipose tissue (IPAT) weight, serum biochemical parameters, and enzymatic activities, mRNA and protein expression levels of lipid metabolism-related enzymes in the liver and IPAT were analyzed. RESULTS: Following administration of caffeine and catechins, body weight gain, IPAT weight, serum and liver concentrations of total cholesterol and triglyceride were markedly reduced. Lipase activities, including that of AMP-activated protein kinase (AMPK), acyl-CoA oxidase, carnitine acyltransferase, adipose triglyceride lipase, and hormone-sensitive lipase, were significantly upregulated; however, fatty acid synthase (FAS) activity in the liver was suppressed. Combined exposure to caffeine and catechins significantly upregulated mRNA and protein expression levels of lipases while downregulating FAS mRNA expression and protein expression of peroxisome proliferator-activated receptor γ2. CONCLUSIONS: The combination of caffeine and catechins regulated the enzymatic activities, mRNA, and protein expression levels of lipid metabolism-related enzymes, resulting in suppression of body weight gain and IPAT weight in mice, potentially through activation of the AMPK signaling pathway. This study indicates that chronic intake of both caffeine and catechins can synergistically contribute to prevention of obesity and lifestyle-related diseases.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Cafeína/farmacologia , Catequina/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/genética , Acil-CoA Oxidase/genética , Acil-CoA Oxidase/metabolismo , Animais , Biomarcadores/sangue , Carnitina Aciltransferases/genética , Carnitina Aciltransferases/metabolismo , Colesterol/sangue , Sinergismo Farmacológico , Ácido Graxo Sintases/sangue , Fezes/química , Feminino , Lipase/genética , Lipase/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Tamanho do Órgão/efeitos dos fármacos , PPAR gama/sangue , Transdução de Sinais , Esterol Esterase/sangue , Triglicerídeos/sangue , Ganho de Peso
20.
Mol Cell Biochem ; 426(1-2): 65-73, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27864727

RESUMO

The carnitine/acylcarnitine transporter (CACT; SLC25A20) mediates an antiport reaction allowing entry of acyl moieties in the form of acylcarnitines into the mitochondrial matrix and exit of free carnitine. The transport function of CACT is crucial for the ß-oxidation pathway. In this work, it has been found that CACT is partially acetylated in rat liver mitochondria as demonstrated by anti-acetyl-lys antibody immunostaining. Acetylation was reversed by the deacetylase Sirtuin 3 in the presence of NAD+. After treatment of the mitochondrial extract with the deacetylase, the CACT activity, assayed in proteoliposomes, increased. The half-saturation constant of the CACT was not influenced, while the V max was increased by deacetylation. Sirtuin 3 was not able to deacetylate the CACT when incubation was performed in intact mitoplasts, indicating that the acetylation sites are located in the mitochondrial matrix. Prediction on the localization of acetylated residues by bioinformatics correlates well with the experimental data. Recombinant CACT treated with acetyl-CoA was partially acetylated by non-enzymatic mechanism with a corresponding decrease of transport activity. The experimental data indicate that acetylation of CACT inhibits its transport activity, and thus may contribute to the regulation of the mitochondrial ß-oxidation pathway.


Assuntos
Carnitina Aciltransferases/metabolismo , Proteínas Mitocondriais/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Acetilação , Animais , Transporte Biológico Ativo/fisiologia , Carnitina Aciltransferases/química , Carnitina Aciltransferases/genética , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , NAD/química , NAD/genética , NAD/metabolismo , Ratos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sirtuína 3/química , Sirtuína 3/genética , Sirtuína 3/metabolismo
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