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1.
J Med Genet ; 61(9): 878-885, 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-38937076

RESUMO

BACKGROUND: Tatton-Brown-Rahman syndrome (TBRS; OMIM 615879), also known as DNA methyltransferase 3 alpha (DNMT3A)-overgrowth syndrome (DOS), was first described by Tatton-Brown in 2014. This syndrome is characterised by overgrowth, intellectual disability and distinctive facial features and is the consequence of germline loss-of-function variants in DNMT3A, which encodes a DNA methyltransferase involved in epigenetic regulation. Somatic variants of DNMT3A are frequently observed in haematological malignancies, including acute myeloid leukaemia (AML). To date, 100 individuals with TBRS with de novo germline variants have been described. We aimed to further characterise this disorder clinically and at the molecular level in a nationwide series of 24 French patients and to investigate the correlation between the severity of intellectual disability and the type of variant. METHODS: We collected genetic and medical information from 24 individuals with TBRS using a questionnaire released through the French National AnDDI-Rares Network. RESULTS: Here, we describe the first nationwide French cohort of 24 individuals with germline likely pathogenic/pathogenic variants in DNMT3A, including 17 novel variants. We confirmed that the main phenotypic features were intellectual disability (100% of individuals), distinctive facial features (96%) and overgrowth (87%). We highlighted novel clinical features, such as hypertrichosis, and further described the neurological features and EEG results. CONCLUSION: This study of a nationwide cohort of individuals with TBRS confirms previously published data and provides additional information and clarifies clinical features to facilitate diagnosis and improve care. This study adds value to the growing body of knowledge on TBRS and broadens its clinical and molecular spectrum.


Assuntos
DNA (Citosina-5-)-Metiltransferases , DNA Metiltransferase 3A , Deficiência Intelectual , Humanos , Masculino , Feminino , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , França/epidemiologia , Criança , DNA (Citosina-5-)-Metiltransferases/genética , Pré-Escolar , Adolescente , Mutação em Linhagem Germinativa/genética , Adulto , Fenótipo , Adulto Jovem , Transtornos do Crescimento/genética , Transtornos do Crescimento/patologia , Lactente
2.
Hum Mol Genet ; 29(12): 1969-1985, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32068834

RESUMO

Vitamin B12 or cobalamin (Cbl) metabolism can be affected by genetic defects leading to defective activity of either methylmalonyl-CoA mutase or methionine synthase or both enzymes. Patients usually present with a wide spectrum of pathologies suggesting that various cellular processes could be affected by modifications in gene expression. We have previously demonstrated that these genetic defects are associated with subcellular mislocalization of RNA-binding proteins (RBP) and subsequent altered nucleo-cytoplasmic shuttling of mRNAs. In order to characterize the possible changes of gene expression in these diseases, we have investigated global gene expression in fibroblasts from patients with cblC and cblG inherited disorders by RNA-seq. The most differentially expressed genes are strongly associated with developmental processes, neurological, ophthalmologic and cardiovascular diseases. These associations are consistent with the clinical presentation of cblC and cblG disorders. Multivariate analysis of transcript processing revaled splicing alterations that led to dramatic changes in cytoskeleton organization, response to stress, methylation of macromolecules and RNA binding. The RNA motifs associated with this differential splicing reflected a potential role of RBP such as HuR and HNRNPL. Proteomic analysis confirmed that mRNA processing was significantly disturbed. This study reports a dramatic alteration of gene expression in fibroblasts of patients with cblC and cblG disorders, which resulted partly from disturbed function of RBP. These data suggest to evaluate the rescue of the mislocalization of RBP as a potential strategy in the treatment of severe cases who are resistant to classical treatments with co-enzyme supplements.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Oxirredutases/genética , Deficiência de Vitamina B 12/genética , Vitamina B 12/genética , Processamento Alternativo/genética , Linhagem Celular , Proteína Semelhante a ELAV 1/genética , Fibroblastos/metabolismo , Regulação da Expressão Gênica/genética , Humanos , Proteômica , Proteínas de Ligação a RNA/genética , Ribonucleoproteínas/genética , Vitamina B 12/metabolismo , Deficiência de Vitamina B 12/patologia
3.
Clin Gastroenterol Hepatol ; 20(9): 1912-1924.e7, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-34902573

RESUMO

Sugar overconsumption is linked to a rise in the incidence of noncommunicable diseases such as diabetes, cardiovascular diseases, and cancer. This increased incidence is becoming a real public health problem that is more severe than infectious diseases, contributing to 35 million deaths annually. Excessive intake of free sugars can cause many of the same health problems as excessive alcohol consumption. Many recent international recommendations have expressed concerns about sugar consumption in Westernized societies, as current consumption levels represent quantities with no precedent during hominin evolution. In both adults and children, the World Health Organization strongly recommends reducing free sugar intake to <10% of total energy intake and suggests a further reduction to below 5%. Most studies have focused on the deleterious effects of Western dietary patterns on global health and the intestine. Whereas excessive dietary fat consumption is well studied, the specific impact of sugar is poorly described, while refined sugars represent up to 40% of caloric intake within industrialized countries. However, high sugar intake is associated with multiple tissue and organ dysfunctions. Both hyperglycemia and excessive sugar intake disrupt the intestinal barrier, thus increasing gut permeability and causing profound gut microbiota dysbiosis, which results in a disturbance in mucosal immunity that enhances infection susceptibility. This review aims to highlight the roles of different types of dietary carbohydrates and the consequences of their excessive intake for intestinal homeostasis.


Assuntos
Doenças Cardiovasculares , Açúcares , Adulto , Criança , Ingestão de Energia , Trato Gastrointestinal , Humanos
4.
Hum Mutat ; 42(12): 1576-1583, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34570399

RESUMO

Aminoacyl-tRNA synthetases (aaRS) are ubiquitously expressed enzymes responsible for ligating amino acids to their cognate tRNA molecules through an aminoacylation reaction. The resulting aminoacyl-tRNA is delivered to ribosome elongation factors to participate in protein synthesis. Seryl-tRNA synthetase (SARS1) is one of the cytosolic aaRSs and catalyzes serine attachment to tRNASer . SARS1 deficiency has already been associated with moderate intellectual disability, ataxia, muscle weakness, and seizure in one family. We describe here a new clinical presentation including developmental delay, central deafness, cardiomyopathy, and metabolic decompensation during fever leading to death, in a consanguineous Turkish family, with biallelic variants (c.638G>T, p.(Arg213Leu)) in SARS1. This missense variant was shown to lead to protein instability, resulting in reduced protein level and enzymatic activity. Our results describe a new clinical entity and expand the clinical and mutational spectrum of SARS1 and aaRS deficiencies.


Assuntos
Aminoacil-tRNA Sintetases , Cardiomiopatias , Surdez , Aminoacil-tRNA Sintetases/genética , Aminoacilação , Cardiomiopatias/genética , Criança , Surdez/genética , Humanos , Perda de Heterozigosidade
5.
Nucleic Acids Res ; 46(15): 7844-7857, 2018 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-30016500

RESUMO

The molecular mechanisms that underlie the neurological manifestations of patients with inherited diseases of vitamin B12 (cobalamin) metabolism remain to date obscure. We observed transcriptomic changes of genes involved in RNA metabolism and endoplasmic reticulum stress in a neuronal cell model with impaired cobalamin metabolism. These changes were related to the subcellular mislocalization of several RNA binding proteins, including the ELAVL1/HuR protein implicated in neuronal stress, in this cell model and in patient fibroblasts with inborn errors of cobalamin metabolism and Cd320 knockout mice. The decreased interaction of ELAVL1/HuR with the CRM1/exportin protein of the nuclear pore complex and its subsequent mislocalization resulted from hypomethylation at R-217 produced by decreased S-adenosylmethionine and protein methyl transferase CARM1 and dephosphorylation at S221 by increased protein phosphatase PP2A. The mislocalization of ELAVL1/HuR triggered the decreased expression of SIRT1 deacetylase and genes involved in brain development, neuroplasticity, myelin formation, and brain aging. The mislocalization was reversible upon treatment with siPpp2ca, cobalamin, S-adenosylmethionine, or PP2A inhibitor okadaic acid. In conclusion, our data highlight the key role of the disruption of ELAVL1/HuR nuclear export, with genomic changes consistent with the effects of inborn errors of Cbl metabolisms on brain development, neuroplasticity and myelin formation.


Assuntos
Transporte Biológico/genética , Proteína Semelhante a ELAV 1/metabolismo , Carioferinas/metabolismo , Doenças Metabólicas/genética , Proteínas de Ligação a RNA/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Vitamina B 12/metabolismo , Animais , Encéfalo/patologia , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Estresse do Retículo Endoplasmático/genética , Humanos , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ácido Okadáico/farmacologia , Fosforilação , Proteína Fosfatase 2/antagonistas & inibidores , Proteína Fosfatase 2/farmacologia , RNA Mensageiro/metabolismo , S-Adenosilmetionina/farmacologia , Sirtuína 1/biossíntese , Proteína Exportina 1
6.
Mol Genet Metab ; 127(1): 58-63, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30954369

RESUMO

Hereditary tyrosinemia type 1 (HT1), the most severe disease of the tyrosine catabolic pathway, is caused by a deficiency of fumarylacetoacetate hydrolase (FAH). More than 90 disease-causing variants have been identified in the fah gene. We investigated the molecular defect in a patient who presented atypical symptoms for the disease. No immunoreactive FAH was found in the liver and RNA analysis by RT-PCR suggested the presence of splicing mutations. Indeed, the patient was revealed to be a compound heterozygote for IVS6-1 g- > t and two new variants, namely p.V259L and p.G398E. Using splicing minigene constructs transfected in HeLa cells, the c.775G > C variant (p.V259L) was shown to affect partially exon 9 splicing thereby allowing the production of some full-length double-mutant FAH transcripts. The p.G398E variant had a major impact on enzyme activity, which was worsened by the p.V259L variant. Surprisingly, the double mutant protein was expressed to similar level as the wild-type protein upon transfection in HeLa cells but was absent in the patient liver extract, suggesting a higher propensity to be degraded in the hepatocellular context.


Assuntos
Hidrolases/genética , Mutação , Tirosinemias/genética , Alelos , Biópsia , Éxons , Feminino , Células HeLa , Humanos , Lactente , Fígado/patologia , Splicing de RNA
7.
Hum Mol Genet ; 22(22): 4591-601, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-23825108

RESUMO

The cblG and cblC disorders of cobalamin (Cbl) metabolism are two inherited causes of megaloblastic anaemia. In cblG, mutations in methionine synthase (MTR) decrease conversion of hydroxocobalamin  (HOCbl) to methylcobalamin, while in cblC, mutations in MMACHC disrupt formation of cob(II)alamin (detected as HOCbl). Cases with undetectable methionine synthase (MS) activity are extremely rare and classified as 'cblG-variant'. In four 'cblG-variant' cases, we observed a decreased conversion of cyanocobalamin to HOCbl that is also seen in cblC cases. To explore this observation, we studied the gene defects, splicing products and expression of MS, as well as MS/MMACHC protein interactions in cblG-variant, cblG, cblC and control fibroblasts. We observed a full-size MS encoded by MTR-001 and a 124 kDa truncated MS encoded by MTR-201 in cblG, cblC, control fibroblasts and HEK cells, but only the MTR-201 transcript and inactive truncated MS in cblG-variant cells. Co-immunoprecipitation and proximity ligation assay showed interaction between truncated MS and MMACHC in cblG-variant cells. This interaction decreased 2.2, 1.5 and 5.0-fold in the proximity ligation assay of cblC cells with p.R161Q and p.R206W mutations, and HEK cells with knock down expression of MS by siRNA, respectively, when compared with control cells. In 3D modelling and docking analysis, both truncated and full-size MS provide a loop anchored to MMACHC, which makes contacts with R-161 and R-206 residues. Our data suggest that the interaction of MS with MMACHC may play a role in the regulation of the cellular processing of Cbls that is required for Cbl cofactor synthesis.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , Anemia Megaloblástica/genética , Proteínas de Transporte/metabolismo , Isoformas de Proteínas/metabolismo , Deficiência de Vitamina B 12/metabolismo , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/química , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Sítios de Ligação/genética , Proteínas de Transporte/química , Proteínas de Transporte/genética , Células Cultivadas , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Hidroxocobalamina/metabolismo , Modelos Moleculares , Simulação de Acoplamento Molecular , Oxirredutases , Ligação Proteica/genética , Isoformas de Proteínas/genética , Estrutura Secundária de Proteína , Vitamina B 12/análogos & derivados , Vitamina B 12/metabolismo , Deficiência de Vitamina B 12/genética
8.
Am J Physiol Endocrinol Metab ; 307(11): E1009-19, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25294213

RESUMO

Early deficiency of the methyl donors folate and vitamin B12 produces hyperhomocysteinemia and cognitive and motor disorders in 21-day-old rat pups from dams fed a diet deficient in methyl donors during gestation and lactation. These disorders are associated with impaired neurogenesis and altered synaptic plasticity in cerebellum. We aimed to investigate whether these disorders could be related to impaired expression of neurosteroidogenesis-associated proteins, key regulator receptors, and some steroid content in the cerebellum. The methyl donor deficiency produced a decreased concentration of folate and vitamin B12, along with accumulation of homocysteine in Purkinje cells in both sexes, whereas the S-adenosylmethionine/S-adenosylhomocysteine ratio was reduced only in females. The transcription level and protein expression of StAR, aromatase, ERα, ERß, and LH receptors were decreased only in females, with a marked effect in Purkinje cells, as shown by immunohistochemistry. Consistently, reduced levels of estradiol and pregnenolone were measured in cerebellar extracts of females only. The decreased expression levels of the transcriptional factors CREB, phospho-CREB, and SF-1, the lesser increase of cAMP concentration, and the lower level of phospho-PKC in the cerebellum of deficient females suggest that the activation of neurosteroidogenesis via cAMP-mediated signaling pathways associated with LHR activation would be altered. In conclusion, a gestational methyl donor deficiency impairs neurosteroidogenesis in cerebellum in a sex-dependent manner.


Assuntos
Cerebelo/metabolismo , AMP Cíclico/fisiologia , Deficiência de Ácido Fólico/metabolismo , Neurotransmissores/biossíntese , Transdução de Sinais/fisiologia , Deficiência de Vitamina B 12/metabolismo , Animais , Estradiol/metabolismo , Feminino , Microssomos/metabolismo , Mitocôndrias/metabolismo , Fosfoproteínas/biossíntese , Fosfoproteínas/genética , Pregnenolona/metabolismo , Ratos , Ratos Wistar , Transcrição Gênica/genética , Transcrição Gênica/fisiologia
9.
Nucleic Acids Res ; 39(8): 3388-403, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21183462

RESUMO

Retroviruses require both spliced and unspliced RNAs for replication. Accumulation of Rous Sarcoma virus (RSV) unspliced RNA depends upon the negative regulator of splicing (NRS). Its 5'-part is considered as an ESE binding SR proteins. Its 3'-part contains a decoy 5'-splice site (ss), which inhibits splicing at the bona fide 5'-ss. Only the 3D structure of a small NRS fragment had been experimentally studied. Here, by chemical and enzymatic probing, we determine the 2D structure of the entire RSV NRS. Structural analysis of other avian NRSs and comparison with all sequenced avian NRSs is in favour of a phylogenetic conservation of the NRS 2D structure. By combination of approaches: (i) in vitro and in cellulo splicing assays, (ii) footprinting assays and (iii) purification and analysis of reconstituted RNP complex, we define a small NRS element retaining splicing inhibitory property. We also demonstrate the capability of the SR protein 9G8 to increase NRS activity in vitro and in cellulo. Altogether these data bring new insights on how NRS fine tune splicing activity.


Assuntos
Processamento Alternativo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , RNA Viral/química , Proteínas de Ligação a RNA/metabolismo , Sequências Reguladoras de Ácido Ribonucleico , Vírus do Sarcoma de Rous/genética , Sequência de Bases , Sítios de Ligação , Células HeLa , Humanos , Dados de Sequência Molecular , Proteínas Nucleares , Conformação de Ácido Nucleico , RNA Viral/metabolismo , Fatores de Processamento de Serina-Arginina
10.
Inflamm Bowel Dis ; 29(6): 986-999, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36545755

RESUMO

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is thought to develop in genetically predisposed individuals as a consequence of complex interactions between dysregulated inflammatory stimuli, immunological responses, and environmental factors. The pathogenesis of IBD has yet to be fully understood. The global increase in the incidence of IBD suggests a gap in the current understanding of the disease. The development of a new diagnostic tool for inflammatory bowel disease that is both less invasive and more cost-effective would allow for better management of this condition. MicroRNAs (miRNAs) are a class of noncoding RNAs with important roles as posttranscriptional regulators of gene expression, which has led to new insights into understanding IBD. Using techniques such as microarrays and real-time polymerase chain reactions, researchers have investigated the patterns in which patients with Crohn's disease and ulcerative colitis show alterations in the expression of miRNA in tissue, blood, and feces. These miRNAs are found to be differentially expressed in IBD and implicated in its pathogenesis through alterations in autophagy, intestinal barrier, and immune homeostasis. In this review, we discuss the miRNA expression profiles associated with IBD in tissue, peripheral blood, and feces and provide an overview of the miRNA mechanisms involved in IBD.


We review the published studies on microRNA (miRNA) expression in inflammatory bowel disease, including miRNAs extracted from blood, tissue, and stool samples. We discuss the main mechanisms of miRNA involvement in inflammatory bowel disease and their potential use as biomarkers.


Assuntos
Colite Ulcerativa , Doença de Crohn , Doenças Inflamatórias Intestinais , MicroRNAs , Humanos , MicroRNAs/metabolismo , Colite Ulcerativa/diagnóstico , Doença de Crohn/diagnóstico , Doenças Inflamatórias Intestinais/diagnóstico , Intestinos
11.
Mol Nutr Food Res ; 67(21): e2300040, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37672803

RESUMO

SCOPE: Disruption of the one carbon metabolism during development, i.e., following a gestational vitamin B9 and B12 deficiencies, is involved in birth defects and brain development delay. Using a rat nutritional model, consisting of pups born to dams fed a vitamin B9 and B12 deficient diet (MDD), the study previously reports molecular and cellular alterations in the brain, in a sex dependent manner, with females being more affected than males. The study hypothesizes that epigenetic modifications could participate in the sex differences is observed. METHODS AND RESULTS: The study investigates lysine methylation of histones and expression of microRNAs in the cerebellum of MDD male and female pups. The study reports a differential regulation of H3K36Me2 and H4K20Me3 between males and females, in response to MDD. Moreover, distinct regulation of Kmt5b and Kdm2a expression by miR-134-5p and miR-369-5p from the Dlk1-Dio3 locus, contributes to the maintenance of expression of genes involved in synaptic plasticity. CONCLUSION: These results could explain the neuroprotection to MDD that male pups display. The work will contribute to the understanding of the consequences of vitamin starvation on brain development, as well as how the epigenome is affected by one carbon metabolism disruption.


Assuntos
MicroRNAs , Ratos , Feminino , Animais , Masculino , Metilação , MicroRNAs/genética , Histonas/genética , Ácido Fólico , Cerebelo , Carbono , Metilação de DNA , Proteínas de Membrana/genética , Peptídeos e Proteínas de Sinalização Intercelular
12.
Sci Rep ; 13(1): 9737, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37322040

RESUMO

Dominantly inherited GAA repeat expansions in FGF14 are a common cause of spinocerebellar ataxia (GAA-FGF14 ataxia; spinocerebellar ataxia 27B). Molecular confirmation of FGF14 GAA repeat expansions has thus far mostly relied on long-read sequencing, a technology that is not yet widely available in clinical laboratories. We developed and validated a strategy to detect FGF14 GAA repeat expansions using long-range PCR, bidirectional repeat-primed PCRs, and Sanger sequencing. We compared this strategy to targeted nanopore sequencing in a cohort of 22 French Canadian patients and next validated it in a cohort of 53 French index patients with unsolved ataxia. Method comparison showed that capillary electrophoresis of long-range PCR amplification products significantly underestimated expansion sizes compared to nanopore sequencing (slope, 0.87 [95% CI, 0.81 to 0.93]; intercept, 14.58 [95% CI, - 2.48 to 31.12]) and gel electrophoresis (slope, 0.84 [95% CI, 0.78 to 0.97]; intercept, 21.34 [95% CI, - 27.66 to 40.22]). The latter techniques yielded similar size estimates. Following calibration with internal controls, expansion size estimates were similar between capillary electrophoresis and nanopore sequencing (slope: 0.98 [95% CI, 0.92 to 1.04]; intercept: 10.62 [95% CI, - 7.49 to 27.71]), and gel electrophoresis (slope: 0.94 [95% CI, 0.88 to 1.09]; intercept: 18.81 [95% CI, - 41.93 to 39.15]). Diagnosis was accurately confirmed for all 22 French Canadian patients using this strategy. We also identified 9 French patients (9/53; 17%) and 2 of their relatives who carried an FGF14 (GAA)≥250 expansion. This novel strategy reliably detected and sized FGF14 GAA expansions, and compared favorably to long-read sequencing.


Assuntos
Ataxia de Friedreich , Ataxias Espinocerebelares , Humanos , Canadá , Ataxia de Friedreich/genética , Ataxias Espinocerebelares/genética , Expansão das Repetições de Trinucleotídeos
13.
J Cell Sci ; 123(Pt 1): 40-50, 2010 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-20016065

RESUMO

RBMY is a male germline RNA binding protein and potential alternative splicing regulator, but the lack of a convenient biological system has made its cellular functions elusive. We found that human RBMY fused to green fluorescent protein was strictly nuclear in transfected cells, but spatially enriched in areas around nuclear speckles with some components of the exon junction complex (EJC). Human RBMY (hRBMY) and the EJC components Magoh and Y14 also physically interacted but, unlike these two proteins, hRBMY protein did not shuttle to the cytoplasm. In addition, it relocalised into nucleolar caps after inhibition of RNA polymerase II transcription. Protein interactions were also detected between RBMY and splicing factors 9G8 and transformer-2 protein homolog beta (Tra2-beta), mediated by multiple regions of the RBMY protein that contain serine/arginine-rich dipeptides, but not by the single region lacking such dipeptides. These interactions modulated the splicing of several pre-mRNAs regulated by 9G8 and Tra2-beta. Importantly, ectopic expression of hRBMY stimulated the inclusion of a testis-enriched exon from the Acinus gene, whereas 9G8 and Tra2-beta repressed this exon. We propose that hRBMY associates with regions of the nucleus enriched in nascent RNA and participates in the regulation of specific splicing events in the germline by modulating the activity of constitutively expressed splicing factors.


Assuntos
Processamento Alternativo , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteínas de Ligação a RNA/metabolismo , Testículo/metabolismo , Animais , Arginina , Células HeLa , Humanos , Masculino , Camundongos , Células NIH 3T3 , Proteínas do Tecido Nervoso/química , Proteínas de Transporte Nucleocitoplasmático/química , Ligação Proteica , Engenharia de Proteínas , Transporte Proteico , RNA Polimerase II/metabolismo , Proteínas de Ligação a RNA/química , Serina , Fatores de Processamento de Serina-Arginina , Testículo/citologia , Ativação Transcricional
14.
Nucleic Acids Res ; 38(4): 1353-66, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19965769

RESUMO

Alternative splicing is regulated in part by variations in the relative concentrations of a variety of factors, including serine/arginine-rich (SR) proteins. The SR protein SC35 self-regulates its expression by stimulating unproductive splicing events in the 3' untranslated region of its own pre-mRNA. Using various minigene constructs containing the terminal retained intron and flanking exons, we identified in the highly conserved last exon a number of exonic splicing enhancer elements responding specifically to SC35, and showed an inverse correlation between affinity of SC35 and enhancer strength. The enhancer region, which is included in a long stem loop, also contains repressor elements, and is recognized by other RNA-binding proteins, notably hnRNP H protein and TAR DNA binding protein (TDP-43). Finally, in vitro and in cellulo experiments indicated that hnRNP H and TDP-43 antagonize the binding of SC35 to the terminal exon and specifically repress the use of SC35 terminal 3' splice site. Our study provides new information about the molecular mechanisms of SC35-mediated splicing activation. It also highlights the existence of a complex network of self- and cross-regulatory mechanisms between splicing regulators, which controls their homeostasis and offers many ways of modulating their concentration in response to the cellular environment.


Assuntos
Processamento Alternativo , Íntrons , Proteínas Nucleares/genética , Proteínas de Ligação a RNA/genética , Sequência de Bases , Sítios de Ligação , Ligação Competitiva , Proteínas de Ligação a DNA/metabolismo , Éxons , Células HeLa , Ribonucleoproteínas Nucleares Heterogêneas Grupo F-H/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Sítios de Splice de RNA , Proteínas de Ligação a RNA/metabolismo , Sequências Reguladoras de Ácido Ribonucleico , Fatores de Processamento de Serina-Arginina
15.
PLoS Genet ; 5(11): e1000707, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19893608

RESUMO

The human testis has almost as high a frequency of alternative splicing events as brain. While not as extensively studied as brain, a few candidate testis-specific splicing regulator proteins have been identified, including the nuclear RNA binding proteins RBMY and hnRNP G-T, which are germ cell-specific versions of the somatically expressed hnRNP G protein and are highly conserved in mammals. The splicing activator protein Tra2beta is also highly expressed in the testis and physically interacts with these hnRNP G family proteins. In this study, we identified a novel testis-specific cassette exon TLE4-T within intron 6 of the human transducing-like enhancer of split 4 (TLE4) gene which makes a more transcriptionally repressive TLE4 protein isoform. TLE4-T splicing is normally repressed in somatic cells because of a weak 5' splice site and surrounding splicing-repressive intronic regions. TLE4-T RNA pulls down Tra2beta and hnRNP G proteins which activate its inclusion. The germ cell-specific RBMY and hnRNP G-T proteins were more efficient in stimulating TLE4-T incorporation than somatically expressed hnRNP G protein. Tra2b bound moderately to TLE4-T RNA, but more strongly to upstream sites to potently activate an alternative 3' splice site normally weakly selected in the testis. Co-expression of Tra2beta with either hnRNP G-T or RBMY re-established the normal testis physiological splicing pattern of this exon. Although they can directly bind pre-mRNA sequences around the TLE4-T exon, RBMY and hnRNP G-T function as efficient germ cell-specific splicing co-activators of TLE4-T. Our study indicates a delicate balance between the activity of positive and negative splicing regulators combinatorially controls physiological splicing inclusion of exon TLE4-T and leads to modulation of signalling pathways in the testis. In addition, we identified a high-affinity binding site for hnRNP G-T protein, showing it is also a sequence-specific RNA binding protein.


Assuntos
Processamento Alternativo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Proteínas Nucleares/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/genética , Espermatozoides/metabolismo , Testículo/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Éxons , Humanos , Íntrons , Masculino , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
16.
Nutrients ; 13(8)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34444978

RESUMO

It is well established that the maternal diet during the periconceptional period affects the progeny's health. A growing body of evidence suggests that the paternal diet also influences disease onset in offspring. For many years, sperm was considered only to contribute half of the progeny's genome. It now appears that it also plays a crucial role in health and disease in offspring's adult life. The nutritional status and environmental exposure of fathers during their childhood and/or the periconceptional period have significant transgenerational consequences. This review aims to describe the effects of various human and rodent paternal feeding patterns on progeny's metabolism and health, including fasting or intermittent fasting, low-protein and folic acid deficient food, and overnutrition in high-fat and high-sugar diets. The impact on pregnancy outcome, metabolic pathways, and chronic disease onset will be described. The biological and epigenetic mechanisms underlying the transmission from fathers to their progeny will be discussed. All these data provide evidence of the impact of paternal nutrition on progeny health which could lead to preventive diet recommendations for future fathers.


Assuntos
Dieta , Pai , Comportamento Alimentar , Fenômenos Fisiológicos da Nutrição , Resultado da Gravidez , Adulto , Animais , Criança , Saúde da Criança , Doença Crônica , Exposição Ambiental , Epigênese Genética , Feminino , Humanos , Masculino , Redes e Vias Metabólicas , Estado Nutricional , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ratos
17.
Adv Nutr ; 12(4): 1558-1570, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-33554240

RESUMO

Immoderate calorie intake coupled with a sedentary lifestyle are major determinants of health issues and inflammatory diseases in modern society. The balance between energy consumption and energy expenditure is critical for longevity. Excessive energy intake and adiposity cause systemic inflammation, whereas calorie restriction (CR) without malnutrition, exerts a potent anti-inflammatory effect. The objective of this review was to provide an overview of different strategies used to reduce calorie intake, discuss physiological mechanisms by which CR might lead to improved health outcomes, and summarize the present knowledge about inflammatory diseases. We discuss emerging data of observational studies and randomized clinical trials on CR that have been shown to reduce inflammation and improve human health.


Assuntos
Restrição Calórica , Longevidade , Adiposidade , Ingestão de Energia , Humanos , Obesidade
18.
Mol Nutr Food Res ; 65(17): e2100206, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34291881

RESUMO

INTRODUCTION: Vitamin B12 deficiency presents various neurological manifestations, such as cognitive dysfunction, mental retardation, or memory impairment. However, the involved molecular mechanisms remain to date unclear. Vitamin B12 is essential for synthesizing S-adenosyl methionine (SAM), the methyl group donor used for almost all transmethylation reactions. Here, we investigate the m6A methylation of mRNAs and their related gene expression in models of vitamin B12 deficiency. METHODS AND RESULTS: This study observes two cellular models deficient in vitamin B12 and hippocampi of mice knock-out for the CD320 receptor. The decrease in SAM levels resulting from vitamin B12 deficiency is associated with m6 A reduced levels in mRNAs. This is also potentially mediated by the overexpression of the eraser FTO. We further investigate mRNA methylation of some genes involved in neurological functions targeted by the m6A reader YTH proteins. We notably observe a m6A hypermethylation of Prkca mRNA and a consistently increased expression of PKCα, a kinase involved in brain development and neuroplasticity, in the two cellular models. CONCLUSION: Our data show that m6A methylation in mRNA could be one of the contributing mechanisms that underlie the neurological manifestations produced by vitamin B12 deficiency.


Assuntos
RNA Mensageiro/metabolismo , Deficiência de Vitamina B 12/genética , Deficiência de Vitamina B 12/fisiopatologia , Adenosina/análogos & derivados , Adenosina/genética , Animais , Fibroblastos , Regulação da Expressão Gênica , Metilação , Camundongos Knockout , Proteína Quinase C-alfa/genética , Proteína Quinase C-alfa/metabolismo , Receptores de Superfície Celular/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , S-Adenosilmetionina/metabolismo , Transcobalaminas/genética , Transcobalaminas/metabolismo , Deficiência de Vitamina B 12/metabolismo
19.
Mol Neurobiol ; 58(3): 1024-1035, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33078371

RESUMO

Cobalamin (Cbl, vitamin B12) deficiency or inborn errors of Cbl metabolism can produce neurologic disorders resistant to therapies, including cognitive dysfunction, mild mental retardation, memory impairment, and confusion. We used Cd320 KO mouse as a model for studying the pathological mechanisms of these disorders. Cd320 encodes the receptor (TCblR) needed for the cellular uptake of Cbl in the brain. The Cd320-/- mouse model presented an impaired learning memory that could be alleviated by a moderate stress, which produced also a greater increase of plasma corticosterone, compared to wild type animals. The present study investigated such a putative rescue mechanism in Cbl-deficient mice. At the molecular level in the brain of Cd320-/- mouse, the decreased methylation status led to a downregulation of glucocorticoid nuclear receptor (GR)/PPAR-gamma co-activator-1 alpha (PGC-1α) pathway. This was evidenced by the decreased expression of GR, decreased methylation of GR and PGC1α, and decreased dimerization and interaction of GR with PGC1α. This led to altered synaptic activity evidenced by decreased interaction between the NMDA glutamatergic receptor and the PSD95 post-synaptic protein and a lower expression of Egr-1 and synapsin 1, in Cd320-/- mice compared to the wild type animals. Intraperitoneal injection of hydrocortisone rescued these molecular changes and normalized the learning memory tests. Our study suggests adaptive influences of moderate stress on loss of memory and cognition due to brain Cbl deficiency. The GR pathway could be a potential target for innovative therapy of cognitive manifestations in patients with poor response to conventional Cbl treatment.


Assuntos
Encéfalo/fisiopatologia , Hipocampo/fisiopatologia , Memória , Plasticidade Neuronal/fisiologia , Receptores de Glucocorticoides/metabolismo , Deficiência de Vitamina B 12/fisiopatologia , Animais , Comportamento Animal/efeitos dos fármacos , Cognição/efeitos dos fármacos , Modelos Animais de Doenças , Glucocorticoides/farmacologia , Hipocampo/efeitos dos fármacos , Hidrocortisona/administração & dosagem , Hidrocortisona/farmacologia , Masculino , Camundongos Knockout , Plasticidade Neuronal/efeitos dos fármacos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Receptores de Superfície Celular/deficiência , Receptores de Superfície Celular/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
20.
Front Nutr ; 8: 758518, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34869528

RESUMO

Nutrition appears to be an important environmental factor involved in the onset of inflammatory bowel diseases (IBD) through yet poorly understood biological mechanisms. Most studies focused on fat content in high caloric diets, while refined sugars represent up to 40% of caloric intake within industrialized countries and contribute to the growing epidemics of inflammatory diseases. Herein we aim to better understand the impact of a high-fat-high-sucrose diet on intestinal homeostasis in healthy conditions and the subsequent colitis risk. We investigated the early events and the potential reversibility of high caloric diet-induced damage in mice before experimental colitis. C57BL/6 mice were fed with a high-fat or high-fat high-sucrose or control diet before experimental colitis. In healthy mice, a high-fat high-sucrose diet induces a pre-IBD state characterized by gut microbiota dysbiosis with a total depletion of bacteria belonging to Barnesiella that is associated with subclinical endoscopic lesions. An overall down-regulation of the colonic transcriptome converged with broadly decreased immune cell populations in the mesenteric lymph nodes leading to the inability to respond to tissue injury. Such in-vivo effects on microbiome and transcriptome were partially restored when returning to normal chow. Long-term consumption of diet enriched in sucrose and fat predisposes mice to colitis. This enhanced risk is preceded by gut microbiota dysbiosis and transcriptional reprogramming of colonic genes related to IBD. Importantly, diet-induced transcriptome and microbiome disturbances are partially reversible after switching back to normal chow with persistent sequelae that may contribute to IBD predisposition in the general population.

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