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1.
EMBO J ; 37(21)2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30237309

RESUMO

The tuberous sclerosis complex (TSC) 1/2 is a negative regulator of the nutrient-sensing kinase mechanistic target of rapamycin complex (mTORC1), and its function is generally associated with tumor suppression. Nevertheless, biallelic loss of function of TSC1 or TSC2 is rarely found in malignant tumors. Here, we show that TSC1/2 is highly expressed in Burkitt's lymphoma cell lines and patient samples of human Burkitt's lymphoma, a prototypical MYC-driven cancer. Mechanistically, we show that MYC induces TSC1 expression by transcriptional activation of the TSC1 promoter and repression of miR-15a. TSC1 knockdown results in elevated mTORC1-dependent mitochondrial respiration enhanced ROS production and apoptosis. Moreover, TSC1 deficiency attenuates tumor growth in a xenograft mouse model. Our study reveals a novel role for TSC1 in securing homeostasis between MYC and mTORC1 that is required for cell survival and tumor maintenance in Burkitt's lymphoma. The study identifies TSC1/2 inhibition and/or mTORC1 hyperactivation as a novel therapeutic strategy for MYC-driven cancers.


Assuntos
Linfoma de Burkitt/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa/metabolismo , Proteína 2 do Complexo Esclerose Tuberosa/metabolismo , Animais , Linfoma de Burkitt/genética , Linfoma de Burkitt/patologia , Células HEK293 , Xenoenxertos , Humanos , Células MCF-7 , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , MicroRNAs/genética , MicroRNAs/metabolismo , Transplante de Neoplasias , Proteínas Proto-Oncogênicas c-myc/genética , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa/genética , Proteína 2 do Complexo Esclerose Tuberosa/genética
2.
Neuropediatrics ; 52(6): 455-461, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33706402

RESUMO

OBJECTIVE: The number of clinical trials for Duchenne muscular dystrophy (DMD) has increased substantially lately, therefore appropriate clinical instruments are needed to measure disease progression and drug efficacy. Jumping mechanography is a medical diagnostic method for motion analysis, which allows to quantify physical parameters. In this study, we compared mechanography with timed function tests (TFTs). METHODS: 41 ambulatory DMD patients performed a total of 95 chair rising tests (CRT) and a total of 76 single two-legged jumps (S2LJ) on a mechanography ground reaction force platform. The results were correlated with a 6-minute walk test (6MWT) and the time required to run 10 meters, stand up from a supine position, and climb four stairs, all performed in the same setting. RESULTS: Our measurements show a high correlation between mechanography and the TFTs: S2LJ/10-m run, r = 0.62; CRT/10-m run, r = 0.61; S2LJ/standing up from supine, r = 0.48; CRT/standing up from supine, r = 0.58; S2LJ/climb four stairs, r = 0.55; CRT/climb four stairs, r = 0.51. The correlation between mechanography and the 6MWT was only moderate with r = 0.38 for S2LJ/6MWT and r = 0.39 for CRT/6MWT. INTERPRETATION: Jumping mechanography is a reliable additional method, which can be used for physical endpoint measurements in clinical trials. We confirmed our assumption, that the method provides additional information concerning performance at movement with higher power output. We suggest using the S2LJ as a first-choice tandem tool combined with the 6MWT. In patients with higher disability, the CRT is an alternative measuring method, because with the progression of the disease this is longer feasible.


Assuntos
Distrofia Muscular de Duchenne , Humanos , Masculino , Movimento , Distrofia Muscular de Duchenne/diagnóstico , Teste de Caminhada
3.
PLoS Genet ; 14(3): e1007272, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29570707

RESUMO

The genetics of lifespan determination is poorly understood. Most research has been done on short-lived animals and it is unclear if these insights can be transferred to long-lived mammals like humans. Some African mole-rats (Bathyergidae) have life expectancies that are multiple times higher than similar sized and phylogenetically closely related rodents. To gain new insights into genetic mechanisms determining mammalian lifespans, we obtained genomic and transcriptomic data from 17 rodent species and scanned eleven evolutionary branches associated with the evolution of enhanced longevity for positively selected genes (PSGs). Indicating relevance for aging, the set of 250 identified PSGs showed in liver of long-lived naked mole-rats and short-lived rats an expression pattern that fits the antagonistic pleiotropy theory of aging. Moreover, we found the PSGs to be enriched for genes known to be related to aging. Among these enrichments were "cellular respiration" and "metal ion homeostasis", as well as functional terms associated with processes regulated by the mTOR pathway: translation, autophagy and inflammation. Remarkably, among PSGs are RHEB, a regulator of mTOR, and IGF1, both central components of aging-relevant pathways, as well as genes yet unknown to be aging-associated but representing convincing functional candidates, e.g. RHEBL1, AMHR2, PSMG1 and AGER. Exemplary protein homology modeling suggests functional consequences for amino acid changes under positive selection. Therefore, we conclude that our results provide a meaningful resource for follow-up studies to mechanistically link identified genes and amino acids under positive selection to aging and lifespan determination.


Assuntos
Longevidade/genética , Roedores/genética , Seleção Genética , Animais , Genoma , Homeostase , Transporte de Íons , Estresse Oxidativo , Especificidade da Espécie , Transcriptoma
4.
Neuropediatrics ; 51(5): 342-348, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32369835

RESUMO

OBJECTIVE: Duchenne muscular dystrophy (DMD) is a devastating X-linked muscular disorder. The number of studies investigating new therapeutic approaches is substantially increasing. This study aims to investigate the impact and diagnostic value of exercise-induced fatigue in DMD, which has been proposed as a suitable outcome parameter in other conditions like spinal muscular atrophy. PATIENTS AND METHODS: A cohort of 55 DMD patients (49 of them treated with steroids and 9 with ataluren) underwent a total of 241 6MWT (mean 4.4 tests/patient) which were retrospectively analyzed. Exercise-induced fatigue was assessed by the ratio between the distance achieved in the sixth minute and the distance in the second minute of the 6MWT. In previous studies a quotient above 1 was defined as a sign of fatigue. RESULTS: The average fatigue quotient in the whole cohort of patients was 1.0. In a further analysis no impact of age, steroid therapy, ataluren therapy, overall disability, and distance in the 6-minute walk test (6MWT) on fatigue in DMD patients could be shown. CONCLUSION: Our data show that fatigue does not play a relevant role in DMD. Analysis of fatigue is not a useful outcome parameter in DMD studies. For this reason we suggest the 2MWT, which is better accepted by the patients, as an alternative to the commonly 6MWT.


Assuntos
Teste de Esforço/normas , Exercício Físico/fisiologia , Fadiga/fisiopatologia , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/fisiopatologia , Adolescente , Criança , Fadiga/etiologia , Humanos , Masculino , Distrofia Muscular de Duchenne/complicações , Valor Preditivo dos Testes , Estudos Retrospectivos
5.
Nucleic Acids Res ; 44(9): 4134-46, 2016 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-26762974

RESUMO

Mutations in the Shwachman-Bodian-Diamond Syndrome (SBDS) gene cause Shwachman-Diamond Syndrome (SDS), a rare congenital disease characterized by bone marrow failure with neutropenia, exocrine pancreatic dysfunction and skeletal abnormalities. The SBDS protein is important for ribosome maturation and therefore SDS belongs to the ribosomopathies. It is unknown, however, if loss of SBDS functionality affects the translation of specific mRNAs and whether this could play a role in the development of the clinical features of SDS. Here, we report that translation of the C/EBPα and -ß mRNAs, that are indispensible regulators of granulocytic differentiation, is altered by SBDS mutations or knockdown. We show that SBDS function is specifically required for efficient translation re-initiation into the protein isoforms C/EBPα-p30 and C/EBPß-LIP, which is controlled by a single cis-regulatory upstream open reading frame (uORF) in the 5' untranslated regions (5' UTRs) of both mRNAs. Furthermore, we show that as a consequence of the C/EBPα and -ß deregulation the expression of MYC is decreased with associated reduction in proliferation, suggesting that failure of progenitor proliferation contributes to the haematological phenotype of SDS. Therefore, our study provides the first indication that disturbance of specific translation by loss of SBDS function may contribute to the development of the SDS phenotype.


Assuntos
Doenças da Medula Óssea/metabolismo , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/genética , Insuficiência Pancreática Exócrina/metabolismo , Lipomatose/metabolismo , Proteínas/fisiologia , RNA Mensageiro/genética , Regiões 5' não Traduzidas , Doenças da Medula Óssea/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Insuficiência Pancreática Exócrina/genética , Expressão Gênica , Regulação da Expressão Gênica , Humanos , Lipomatose/genética , Neutrófilos/fisiologia , Iniciação Traducional da Cadeia Peptídica , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/metabolismo , Síndrome de Shwachman-Diamond
6.
Aging Ment Health ; 22(6): 748-754, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28357883

RESUMO

OBJECTIVES: Mood regulation is said to be age-specific. Negative self-statements (NST) are used to induce negative mood. However, little is known about NST in older persons and geriatric patients with major depressive disorder. METHOD: We investigated healthy young (YC) and older (OC) control subjects and older patients with major depressive disorder (OP). Subjects were exposed to NST subsequent to baseline assessment comprising psychological and psychometric tests. Preferences for emotionally salient stimuli were measured with an eye-tracking task. RESULTS: Mood in YC shifted towards depressive mood or remained stable on NST. In OC and more so in OP some subjects responded paradoxically subsequent to NST with mood being more positive than at baseline. Extent and direction of mood change correlated with prevailing mood at baseline and total score in the Hamilton Depression Anxiety Scale. At baseline, YC had a preference for 'happy' stimuli. Subsequent to NST view preference shifted towards 'sad.' In contrast, OC had no preference at baseline but shifted towards 'happy' on NST. CONCLUSIONS: Mood change on NST is age-specific. In geriatric patients with depressive disorder, however, NST may induce a shift towards more positive mood and thus may be used in future as a therapeutic intervention.


Assuntos
Envelhecimento/fisiologia , Transtorno Depressivo Maior/fisiopatologia , Emoções/fisiologia , Autoimagem , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade , Adulto Jovem
7.
EMBO Rep ; 16(8): 1022-36, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26113365

RESUMO

The mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of physiological adaptations in response to changes in nutrient supply. Major downstream targets of mTORC1 signalling are the mRNA translation regulators p70 ribosomal protein S6 kinase 1 (S6K1p70) and the 4E-binding proteins (4E-BPs). However, little is known about vertebrate mRNAs that are specifically controlled by mTORC1 signalling and are engaged in regulating mTORC1-associated physiology. Here, we show that translation of the CCAAT/enhancer binding protein beta (C/EBPß) mRNA into the C/EBPß-LIP isoform is suppressed in response to mTORC1 inhibition either through pharmacological treatment or through calorie restriction. Our data indicate that the function of 4E-BPs is required for suppression of LIP. Intriguingly, mice lacking the cis-regulatory upstream open reading frame (uORF) in the C/EBPß-mRNA, which is required for mTORC1-stimulated translation into C/EBPß-LIP, display an improved metabolic phenotype with features also found under calorie restriction. Thus, our data suggest that translational adjustment of C/EBPß-isoform expression is one of the key processes that direct metabolic adaptation in response to changes in mTORC1 activity.


Assuntos
Proteína beta Intensificadora de Ligação a CCAAT/genética , Metabolismo dos Lipídeos , Complexos Multiproteicos/metabolismo , RNA Mensageiro/genética , Serina-Treonina Quinases TOR/metabolismo , Adipogenia/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/deficiência , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Restrição Calórica , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Complexos Multiproteicos/antagonistas & inibidores , Complexos Multiproteicos/genética , Fases de Leitura Aberta , Oxirredução , Fenótipo , Biossíntese de Proteínas , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais , Sirolimo , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/genética
8.
Environ Microbiol ; 17(11): 4352-65, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25809238

RESUMO

In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.


Assuntos
Achromobacter denitrificans/metabolismo , Pseudomonas aeruginosa/metabolismo , Quinolonas/metabolismo , Percepção de Quorum/fisiologia , Metabolismo Secundário/fisiologia , Dados de Sequência Molecular , Oxirredução , Floresta Úmida , Transdução de Sinais , Solo/química , Microbiologia do Solo
9.
Appl Environ Microbiol ; 81(22): 7720-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26319870

RESUMO

Rhodococcus erythropolis BG43 is able to degrade the Pseudomonas aeruginosa quorum sensing signal molecules PQS (Pseudomonas quinolone signal) [2-heptyl-3-hydroxy-4(1H)-quinolone] and HHQ [2-heptyl-4(1H)-quinolone] to anthranilic acid. Based on the hypothesis that degradation of HHQ might involve hydroxylation to PQS followed by dioxygenolytic cleavage of the heterocyclic ring and hydrolysis of the resulting N-octanoylanthranilate, the genome was searched for corresponding candidate genes. Two gene clusters, aqdA1B1C1 and aqdA2B2C2, each predicted to code for a hydrolase, a flavin monooxygenase, and a dioxygenase related to 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase, were identified on circular plasmid pRLCBG43 of strain BG43. Transcription of all genes was upregulated by PQS, suggesting that both gene clusters code for alkylquinolone-specific catabolic enzymes. An aqdR gene encoding a putative transcriptional regulator, which was also inducible by PQS, is located adjacent to the aqdA2B2C2 cluster. Expression of aqdA2B2C2 in Escherichia coli conferred the ability to degrade HHQ and PQS to anthranilic acid; however, for E. coli transformed with aqdA1B1C1, only PQS degradation was observed. Purification of the recombinant AqdC1 protein verified that it catalyzes the cleavage of PQS to form N-octanoylanthranilic acid and carbon monoxide and revealed apparent Km and kcat values for PQS of ∼27 µM and 21 s(-1), respectively. Heterologous expression of the PQS dioxygenase gene aqdC1 or aqdC2 in P. aeruginosa PAO1 quenched the production of the virulence factors pyocyanin and rhamnolipid and reduced the synthesis of the siderophore pyoverdine. Thus, the toolbox of quorum-quenching enzymes is expanded by new PQS dioxygenases.


Assuntos
Pseudomonas aeruginosa/genética , Percepção de Quorum , Rhodococcus/genética , Fatores de Virulência/genética , Regulação Bacteriana da Expressão Gênica , Glicolipídeos/genética , Glicolipídeos/metabolismo , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Filogenia , Plasmídeos , Pseudomonas aeruginosa/metabolismo , Piocianina/genética , Piocianina/metabolismo , Quinolonas/metabolismo , Rhodococcus/metabolismo , Análise de Sequência de DNA , Fatores de Virulência/metabolismo
10.
EMBO J ; 29(5): 897-909, 2010 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-20075868

RESUMO

The messenger RNA of the intronless CEBPA gene is translated into distinct protein isoforms through the usage of consecutive translation initiation sites. These translational isoforms have distinct functions in the regulation of differentiation and proliferation due to the presence of different N-terminal sequences. Here, we describe the function of an N-terminally extended protein isoform of CCAAT enhancer-binding protein alpha (C/EBPalpha) that is translated from an alternative non-AUG initiation codon. We show that a basic amino-acid motif within its N-terminus is required for nucleolar retention and for interaction with nucleophosmin (NPM). In the nucleoli, extended-C/EBPalpha occupies the ribosomal DNA (rDNA) promoter and associates with the Pol I-specific factors upstream-binding factor 1 (UBF-1) and SL1 to stimulate rRNA synthesis. Furthermore, during differentiation of HL-60 cells, endogenous expression of extended-C/EBPalpha is lost concomitantly with nucleolar C/EBPalpha immunostaining probably reflecting the reduced requirement for ribosome biogenesis in differentiated cells. Finally, overexpression of extended-C/EBPalpha induces an increase in cell size. Altogether, our results suggest that control of rRNA synthesis is a novel function of C/EBPalpha adding to its role as key regulator of cell growth and proliferation.


Assuntos
Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Nucléolo Celular/metabolismo , DNA Ribossômico/genética , Northern Blotting , Western Blotting , Tamanho Celular , Imunoprecipitação da Cromatina , Vetores Genéticos/genética , Células HL-60 , Humanos , Imunoprecipitação , Lentivirus/genética , Proteínas Nucleares/metabolismo , Nucleofosmina , Fosforilação , Proteínas Pol1 do Complexo de Iniciação de Transcrição/metabolismo , Regiões Promotoras Genéticas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiologia , RNA Polimerase I/metabolismo , Retroviridae/genética , Transcrição Gênica/genética , Células U937
11.
Appl Environ Microbiol ; 80(23): 7266-74, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25239889

RESUMO

A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule.


Assuntos
Quinolonas/metabolismo , Rhodococcus/metabolismo , Microbiologia do Solo , Proteínas de Bactérias/genética , Biotransformação , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Rhodococcus/classificação , Rhodococcus/genética , Rhodococcus/isolamento & purificação , Análise de Sequência de DNA
12.
Am J Med Genet A ; 161A(2): 360-70, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23322711

RESUMO

In 1973, Singleton and Merten described two females with abnormal dentition, unique radiographic changes especially of the hands, and severe calcification and intimal weakening of the aortic arch and valve. Since then three additional cases with similar features have been reported and the diagnosis was suggested in another three individuals. We present an update of one case and the detailed clinical phenotype of six other cases with Singleton-Merten syndrome. The occurrence of the disorder in six members of two families and vertical male-to-male transmission indicate an autosomal dominant pattern of inheritance. Variability in phenotype, also within a single family, is significant. Core manifestations are marked aortic calcification, dental anomalies (delayed eruption and immature root formation of primarily the anterior permanent teeth, and early loss of permanent teeth due to short roots, acute root resorption, high caries, and aggressive alveolar bone loss), osteopenia and acro-osteolysis, and to a lesser extend also glaucoma, psoriasis, muscle weakness, and joint laxity. Additional clinical characteristics described here include particular facial characteristics (high anterior hairline, broad forehead, smooth philtrum, thin upper vermillion) and abnormal joint and muscle ligaments. The cause and pathogenesis of this syndrome remain unknown. © 2013 Wiley Periodicals, Inc.


Assuntos
Anormalidades Múltiplas/genética , Doenças da Aorta/genética , Hipoplasia do Esmalte Dentário/genética , Genes Dominantes , Doenças Musculares/genética , Odontodisplasia/genética , Osteoporose/genética , Calcificação Vascular/genética , Adulto , Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/mortalidade , Pré-Escolar , Hipoplasia do Esmalte Dentário/diagnóstico por imagem , Hipoplasia do Esmalte Dentário/mortalidade , Feminino , Humanos , Lactente , Masculino , Metacarpo/anormalidades , Metacarpo/diagnóstico por imagem , Doenças Musculares/diagnóstico por imagem , Doenças Musculares/mortalidade , Miocárdio/patologia , Odontodisplasia/diagnóstico por imagem , Odontodisplasia/mortalidade , Osteoporose/diagnóstico por imagem , Osteoporose/mortalidade , Fenótipo , Psoríase/genética , Radiografia , Crânio/diagnóstico por imagem , Crânio/patologia , Perda de Dente/genética , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/mortalidade
13.
Biotechnol Bioeng ; 110(6): 1714-25, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23335282

RESUMO

Cerium (IV) initiated "graft-from" polymerization reactions were employed to convert M-PVA magnetic particles into polyacrylic acid-fimbriated magnetic cation exchange supports displaying ultra-high binding capacity for basic target proteins. The modifications, which were performed at 25 mg and 2.5 g scales, delivered maximum binding capacities (Qmax ) for hen egg white lysozyme in excess of 320 mg g(-1) , combined with sub-micromolar dissociation constants (0.45-0.69 µm) and "tightness of binding" values greater than 49 L g(-1) . Two batches of polyacrylic acid-fimbriated magnetic cation exchangers were combined to form a 5 g pooled batch exhibiting Qmax values for lysozyme, lactoferrin, and lactoperoxidase of 404, 585, and 685 mg g(-1) , respectively. These magnetic cation exchangers were subsequently employed together with a newly designed "rotor-stator" type HGMF rig, in five sequential cycles of recovery of lactoferrin and lactoperoxidase from 2 L batches of a crude sweet bovine whey feedstock. Lactoferrin purification performance was observed to remain relatively constant from one HGMF cycle to the next over the five operating cycles, with yields between 40% and 49% combined with purification and concentration factors of 37- to 46-fold and 1.3- to 1.6-fold, respectively. The far superior multi-cycle HGMF performance seen here compared to that observed in our earlier studies can be directly attributed to the combined use of improved high capacity adsorbents and superior particle resuspension afforded by the new "rotor-stator" HGMS design.


Assuntos
Cromatografia por Troca Iônica/instrumentação , Cromatografia por Troca Iônica/métodos , Lactoferrina/isolamento & purificação , Lactoperoxidase/isolamento & purificação , Imãs , Leite/química , Resinas Acrílicas/química , Adsorção , Animais , Biotecnologia/instrumentação , Biotecnologia/métodos , Cátions/química , Bovinos , Eletroforese em Gel de Poliacrilamida , Desenho de Equipamento , Ligação Proteica
14.
Appl Microbiol Biotechnol ; 97(2): 751-60, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22740050

RESUMO

The quorum sensing signalling molecules 2-heptyl-3-hydroxy-4(1H)-quinolone, termed the "Pseudomonas quinolone signal" (PQS), and 2-heptyl-4(1H)-quinolone (HHQ) play an important role in the control of virulence gene expression in Pseudomonas aeruginosa. To construct a bioreporter for the specific and sensitive detection of these compounds, a plasmid with the pqsR gene encoding the PQS- and HHQ-responsive transcriptional regulator PqsR, and with the PqsR-controlled pqsA promoter fused to the lacZ gene, was established in Pseudomonas putida KT2440. The bioreporter responds to HHQ and PQS at concentrations in the range of 0.1-10 and 0.01-5 µM, respectively, with EC(50) values of 1.50 ± 0.25 µM for HHQ and 0.15 ± 0.02 µM for PQS. 2,4-Dihydroxyquinoline, a metabolite produced abundantly by P. aeruginosa, did not elicit an increase in reporter enzyme activity. To test whether the bioreporter can be used for the detection of enzymes active on AQ signalling molecules, the hodC gene coding for 2-methyl-3-hydroxy-4(1H)-quinolone 2,4-dioxygenase was expressed in the reporter strain. This dioxygenase catalyses the cleavage of PQS, albeit with very low activity. The response of the bioreporter to PQS was significantly quenched by co-expression of the hodC gene, and HPLC analysis of culture extracts verified that the PQS levels decreased during cultivation. The bioreporter can be applied to screen for AQ-converting enzymes, which will be useful tools to interfere with quorum sensing and thus virulence in P. aeruginosa.


Assuntos
Reatores Biológicos/microbiologia , Enzimas/metabolismo , Pseudomonas putida/crescimento & desenvolvimento , Pseudomonas putida/metabolismo , Quinolonas/metabolismo , Cromatografia Líquida de Alta Pressão , Percepção de Quorum/fisiologia
15.
Mol Metab ; 72: 101726, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37062524

RESUMO

OBJECTIVE: Cancer cells use glycolysis for generation of metabolic intermediates and ATP needed for cell growth and proliferation. The transcription factor C/EBPß-LIP stimulates glycolysis and mitochondrial respiration in cancer cells. We initially observed that high expression of C/EBPß-LIP makes cells vulnerable to treatment with the glycolysis inhibitor 2-deoxyglucose. The aim of the study was to uncover the involved mechanisms of C/EBPß-LIP induced sensitivity to glycolysis inhibition. METHODS: We used genetically engineered cell lines to examine the effect of C/EBPß-LIP and -LAP protein isoforms on glycolysis and NADH/NAD+ metabolism in mouse embryonic fibroblasts (MEFs), and triple negative breast cancer (TNBC) cells that endogenously express high levels of C/EBPß-LIP. Analyses included assays of cell proliferation, cell survival and metabolic flux (OCR and ECAR by Seahorse XF96). Small molecule inhibitors were used to identify underlying metabolic pathways that mediate sensitivity to glycolysis inhibition induced by C/EBPß-LIP. RESULTS: The transcription factor C/EBPß-LIP stimulates both glycolysis and the malate-aspartate shuttle (MAS) and increases the sensitivity to glycolysis inhibition (2-deoxyglucose) in fibroblasts and breast cancer cells. Inhibition of glycolysis with ongoing C/EBPß-LIP-induced MAS activity results in NADH depletion and apoptosis that can be rescued by inhibiting either the MAS or other NAD+-regenerating processes. CONCLUSION: This study indicates that a low NADH/NAD+ ratio is an essential mediator of 2-deoxyglucose toxicity in cells with high cytoplasmic NAD+-regeneration capacity and that simultaneous inhibition of glycolysis and lowering of the NADH/NAD+ ratio may be considered to treat cancer.


Assuntos
Ácido Aspártico , Proteína beta Intensificadora de Ligação a CCAAT , Animais , Camundongos , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Ácido Aspártico/metabolismo , Malatos/metabolismo , NAD/metabolismo , Fibroblastos/metabolismo , Glicólise , Desoxiglucose
16.
J Neuromuscul Dis ; 10(1): 55-65, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36463459

RESUMO

Now that targeted therapies for spinal muscular atrophy are available, attempts are being made worldwide to include screening for spinal muscular atrophy in general newborn screening. In Germany, after pilot projects from 2018-2021, it was included in the general newborn screening from October 2021. To ensure a smooth transition, criteria for follow-up were developed together with key stakeholders. At the beginning of the transition to nationwide screening, false positive findings were reported in 3 patients. After optimization of the screening method in the laboratories concerned, all findings have been subsequently confirmed. On average, the first presentation to a neuromuscular center occurred on day 12 of life, and in patients with 2 or 3 SMN2 copies, therapy started on day 26 of life. Compared with the pilot project, there was no significant delay in timing.


Assuntos
Atrofia Muscular Espinal , Recém-Nascido , Humanos , Projetos Piloto , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/epidemiologia , Atrofia Muscular Espinal/terapia , Triagem Neonatal/métodos , Alemanha , Tempo
17.
Proc Biol Sci ; 279(1748): 4845-52, 2012 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-23034701

RESUMO

Understanding the functional consequences of biodiversity loss is a major goal of ecology. Animal-mediated pollination is an essential ecosystem function and service provided to mankind. However, little is known how pollinator diversity could affect pollination services. Using a substitutive design, we experimentally manipulated functional group (FG) and species richness of pollinator communities to investigate their consequences on the reproductive success of an obligate out-crossing model plant species, Raphanus sativus. Both fruit and seed set increased with pollinator FG richness. Furthermore, seed set increased with species richness in pollinator communities composed of a single FG. However, in multiple-FG communities, highest species richness resulted in slightly reduced pollination services compared with intermediate species richness. Our analysis indicates that the presence of social bees, which showed roughly four times higher visitation rates than solitary bees or hoverflies, was an important factor contributing to the positive pollinator diversity-pollination service relationship, in particular, for fruit set. Visitation rate at different daytimes, and less so among flower heights, varied among social bees, solitary bees and hoverflies, indicating a niche complementarity among these pollinator groups. Our study demonstrates enhanced pollination services of diverse pollinator communities at the plant population level and suggests that both the niche complementarity and the presence of specific taxa in a pollinator community drive this positive relationship.


Assuntos
Biodiversidade , Fenômenos Fisiológicos Vegetais , Polinização , Animais , Abelhas , Ecossistema , Flores , Frutas , Raphanus/fisiologia , Reprodução
18.
Toxicol Appl Pharmacol ; 263(3): 352-9, 2012 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-22820422

RESUMO

Lipocalins tailored with high affinity for prescribed ligands, so-called anticalins, constitute promising candidates as antidotes. Here, we present an animal study to investigate both pharmacokinetic and clinical effects of an anticalin specific for the digitalis compound digoxin. Intravenous digoxin (2.5-50 µg/kg/min) was administered to rats until first changes in the ECG occurred (dose finding study) or a priori for 30 min (kinetic study). The anticalin DigA16(H86N), dubbed DigiCal, was administered intravenously at absolute doses of 1, 5, 10 and 20 mg, while the control group received isotonic saline. Hemodynamic changes, several ECG parameters and digoxin concentration in plasma were monitored at given time intervals. After DigiCal administration free digoxin concentration in plasma ultrafiltrate declined dramatically within 1 min to the presumably non-toxic range. There was also a significant and DigiCal dose-dependent effect on longer survival, less ECG alterations, arrhythmia, and improved hemodynamics. Infusion of a lower digoxin dose (2.5 µg/kg/min) resulted in a more sustained reduction of free digoxin in plasma after DigiCal administration compared to a higher digoxin dose (25 µg/kg/min), whereas ECG and hemodynamic parameters did not markedly differ, reflecting the known relative insensitivity of rats towards digoxin toxicity. Notably, we observed a re-increase of free digoxin in plasma some time after bolus administration of DigiCal, which was presumably due to toxin redistribution from tissue in combination with the relatively fast renal clearance of the rather small protein antidote. We conclude that anticalins with appropriately engineered drug-binding activities and, possibly, prolonged plasma half-life offer prospects for next-generation antidotal therapy.


Assuntos
Antídotos/farmacologia , Cardiotônicos/toxicidade , Digoxina/toxicidade , Lipocalinas/farmacologia , Animais , Antídotos/administração & dosagem , Cardiotônicos/administração & dosagem , Cardiotônicos/farmacocinética , Digoxina/administração & dosagem , Digoxina/farmacocinética , Relação Dose-Resposta a Droga , Eletrocardiografia , Meia-Vida , Infusões Intravenosas , Lipocalinas/administração & dosagem , Masculino , Ratos , Ratos Sprague-Dawley , Taxa de Sobrevida , Fatores de Tempo
19.
RSC Chem Biol ; 3(4): 426-430, 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35441139

RESUMO

This report describes the application of cyanosulfurylide (CSY)-protected aspartatic acid building blocks in microwave-assisted synthesis of aggregation-prone protein domains. We present a synthesis of Fmoc-Asp(CSY)-OH on a multigram scale, as well as procedures for the microwave-assisted synthesis of CSY-protected peptides, and CSY cleavage in partially folded or aggregation-prone peptides.

20.
Elife ; 112022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35451956

RESUMO

Chronic obesity is correlated with severe metabolic and cardiovascular diseases as well as with an increased risk for developing cancers. Obesity is usually characterized by fat accumulation in enlarged - hypertrophic - adipocytes that are a source of inflammatory mediators, which promote the development and progression of metabolic disorders. Yet, in certain healthy obese individuals, fat is stored in metabolically more favorable hyperplastic fat tissue that contains an increased number of smaller adipocytes that are less inflamed. In a previous study, we demonstrated that loss of the inhibitory protein-isoform C/EBPß-LIP and the resulting augmented function of the transactivating isoform C/EBPß-LAP promotes fat metabolism under normal feeding conditions and expands health- and lifespan in mice. Here, we show that in mice on a high-fat diet, LIP-deficiency results in adipocyte hyperplasia associated with reduced inflammation and metabolic improvements. Furthermore, fat storage in subcutaneous depots is significantly enhanced specifically in LIP-deficient male mice. Our data identify C/EBPß as a regulator of adipocyte fate in response to increased fat intake, which has major implications for metabolic health and aging.


Assuntos
Dieta Hiperlipídica , Fígado Gorduroso , Tecido Adiposo/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/metabolismo , Hiperplasia/metabolismo , Hipertrofia , Masculino , Camundongos , Obesidade/metabolismo , Isoformas de Proteínas/metabolismo
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