RESUMO
Hyperinflammatory syndromes are life-threatening disorders caused by overzealous immune cell activation and cytokine release, often resulting from defects in negative feedback mechanisms. In the quintessential hyperinflammatory syndrome familial hemophagocytic lymphohistiocytosis (HLH), inborn errors of cytotoxicity result in effector cell accumulation, immune dysregulation and, if untreated, tissue damage and death. Here, we describe a human case with a homozygous nonsense R688* RC3H1 mutation suffering from hyperinflammation, presenting as relapsing HLH. RC3H1 encodes Roquin-1, a posttranscriptional repressor of immune-regulatory proteins such as ICOS, OX40 and TNF. Comparing the R688* variant with the murine M199R variant reveals a phenotypic resemblance, both in immune cell activation, hypercytokinemia and disease development. Mechanistically, R688* Roquin-1 fails to localize to P-bodies and interact with the CCR4-NOT deadenylation complex, impeding mRNA decay and dysregulating cytokine production. The results from this unique case suggest that impaired Roquin-1 function provokes hyperinflammation by a failure to quench immune activation.
Assuntos
Linfo-Histiocitose Hemofagocítica/genética , Proteínas de Ligação a RNA/genética , Ubiquitina-Proteína Ligases/genética , Adolescente , Animais , Códon sem Sentido , Consanguinidade , Ciclosporina/uso terapêutico , Eosinofilia/genética , Eosinofilia/imunologia , Homozigoto , Humanos , Imunofenotipagem , Imunossupressores/uso terapêutico , Proteína Coestimuladora de Linfócitos T Induzíveis/genética , Proteína Coestimuladora de Linfócitos T Induzíveis/imunologia , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/imunologia , Masculino , Camundongos , Monócitos/imunologia , Receptores OX40/genética , Receptores OX40/imunologia , Receptores OX40/metabolismo , Recidiva , Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Ubiquitina-Proteína Ligases/imunologiaRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Recombinant Penicillium citrinum alpha-1,2-mannosidase, expressed in Aspergillus oryzae, was employed to carry out regioselective synthesis of alpha- d-mannopyranosyl-(1-->2)- d-mannose. Yields (w/w) of 16.68% disaccharide, 3.07% trisaccharide and 0.48% tetrasaccharide were obtained, with alpha1-->2 linkages present at 98.5% of the total linkages formed. Non-specific alpha-mannosidase from almond was highly efficient in reverse hydrolysis and oligosaccharide yields of 45-50% were achieved. The products of the almond mannosidase were a mixture of disaccharides (30.75%, w/w), trisaccharides (12.26%, w/w) and tetrasaccharides (1.89%, w/w) with 1-->2, 1-->3 and 1-->6 isomers. alpha-1,2-linkage specific mannosidase from P. citrinum and alpha-1,6-linkage-specific mannosidase from Aspergillus phoenicis were used in combination to hydrolyse the respective linkages from the mixture of isomers, resulting in alpha- d-mannopyranosyl-(1-->3)- d-mannose in 86.4% purity. The synthesised oligosaccharides can potentially inhibit the adhesion of pathogens by acting as "decoys" of receptors of type-1 fimbriae carried by enterobacteria.
Assuntos
Manosídeos/biossíntese , Oligossacarídeos/biossíntese , Oligossacarídeos/isolamento & purificação , alfa-Manosidase/metabolismo , Adesinas de Escherichia coli/metabolismo , Aspergillus/enzimologia , Aspergillus/genética , Aderência Bacteriana/efeitos dos fármacos , Configuração de Carboidratos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Estabilidade Enzimática , Proteínas de Fímbrias/metabolismo , Genes Fúngicos , Concentração de Íons de Hidrogênio , Hidrólise , Manosidases/metabolismo , Oligossacarídeos/análise , Oligossacarídeos/química , Oligossacarídeos/farmacologia , Penicillium/enzimologia , Penicillium/genética , Prunus/enzimologia , Receptores Imunológicos/metabolismo , Temperatura , alfa-Manosidase/genética , alfa-Manosidase/isolamento & purificaçãoRESUMO
A 2,385-bp sequence that contains the information for the autonomous replication of the IncL/M plasmid pMU604 was characterized. Genetic analyses revealed that the replicon specifies at least four structural genes, designated repA, repB, repC, and rnaI. The repA gene encodes a protein with a molecular weight of 40,861 which probably functions as an initiator for replication. The functions of the proteins of the repB and repC genes are unclear; however, mutations in the start codon of repB reduced the expression of both repB and repA, indicating that these two genes are translationally coupled. The rnal gene encodes a small antisense RNA of about 75 to 77 bases and is responsible for the incompatibility phenotype, thus implicating its role as the main copy number determinant. RNAI exerts its effect in trans to repress the expression of repA at the posttranscriptional level. Furthermore, two complementary sequences of 8 bases, with the potential to interact and form a putative pseudoknot structure, were identified in the leader region of the repA mRNA. Base-pairing between the two complementary sequences was shown to be critical for efficient repA expression. A model for the regulation of pMU604 replication involving both translational coupling and pseudoknot formation is proposed.
Assuntos
DNA Helicases , Replicação do DNA , Proteínas de Ligação a DNA , Regulação Bacteriana da Expressão Gênica , Plasmídeos/genética , Proteínas , RNA Antissenso/genética , RNA Bacteriano/genética , Transativadores , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Sequência de Bases , Northern Blotting , Genes Bacterianos/genética , Genes Reporter , Modelos Genéticos , Dados de Sequência Molecular , Conformação de Ácido Nucleico , RNA Mensageiro/genética , RNA Interferente Pequeno , Proteínas Recombinantes de Fusão/biossíntese , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Transcrição GênicaRESUMO
Replication of the IncL/M plasmid pMU604 is controlled by a small antisense RNA molecule (RNAI), which, by inhibiting the formation of an RNA pseudoknot, regulates translation of the replication initiator protein, RepA. Efficient translation of the repA mRNA was shown to require the translation and correct termination of the leader peptide, RepB, and the formation of the pseudoknot. Although the pseudoknot was essential for the expression of repA, its presence was shown to interfere with the translation of repB. The requirement for pseudoknot formation could in large part be obviated by improving the ribosome binding region of repA, either by replacing the GUG start codon by AUG or by increasing the spacing between the start codon and the Shine-Dalgarno sequence (SD). The spacing between the distal pseudoknot sequence and the repA SD was shown to be suboptimal for maximal expression of repA.
Assuntos
DNA Helicases , Proteínas de Ligação a DNA , Genes Bacterianos , Plasmídeos/genética , Proteínas/genética , RNA Antissenso/química , RNA Antissenso/genética , RNA Bacteriano/química , RNA Bacteriano/genética , Transativadores , Proteínas de Bactérias/genética , Sequência de Bases , Códon de Iniciação/genética , Códon de Terminação/genética , Replicação do DNA/genética , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Dados de Sequência Molecular , Mutação , Conformação de Ácido Nucleico , Biossíntese de Proteínas , RNA Mensageiro/química , RNA Mensageiro/genética , Deleção de SequênciaRESUMO
Extraskeletal tumoral calcifications (TC) may occur in patients with end-stage renal disease. The TC usually develop in the presence of secondary hyperparathyroidism or a high calcium x phosphate product, while other factors have been also occasionally implicated in their development. At present, no uniformly accepted effective treatment has been described for this condition. We describe a 58-year-old female patient with end-stage renal disease who 7 years after the onset of dialysis presented with pain and movement restriction of various joints. A skeletal X-ray showed huge amounts of periarticular TC. The TC occurred in the absence of hyperparathyroidism or a high calcium x phosphate product as evidenced by hormonal and biochemical examination as well as by a bone biopsy specimen that revealed an adynamic bone disease with significant aluminum staining. Sodium thiosulfate, an inorganic salt that has been claimed to inhibit the formation and to favor the solubility and the mobilization of calcified masses, was administered to the patient, and after a long period of treatment considerable radiological regression of the TC with concurrent clinical recovery was noticed. Aluminum intoxication, along with other factors, was considered to be the cause of TC development. The use of sodium thiosulfate seemed to be a reasonable nonspecific therapeutic approach for the management of TC in this case.