RESUMO
A major arm of cellular innate immunity is type I interferon (IFN), represented by IFN-α and IFN-ß. Type I IFN transcriptionally induces a large number of cellular genes, collectively known as IFN-stimulated gene (ISG) proteins, which act as antivirals. The IFIT (interferon-induced proteins with tetratricopeptide repeats) family proteins constitute a major subclass of ISG proteins and are characterized by multiple tetratricopeptide repeats (TPRs). In this study, we have interrogated IFIT proteins for the ability to inhibit the growth of human parainfluenza virus type 3 (PIV3), a nonsegmented negative-strand RNA virus of the Paramyxoviridae family and a major cause of respiratory disease in children. We found that IFIT1 significantly inhibited PIV3, whereas IFIT2, IFIT3, and IFIT5 were less effective or not at all. In further screening a set of ISG proteins we discovered that several other such proteins also inhibited PIV3, including IFITM1, IDO (indoleamine 2,3-dioxygenase), PKR (protein kinase, RNA activated), and viperin (virus inhibitory protein, endoplasmic reticulum associated, interferon inducible)/Cig5. The antiviral effect of IDO, the enzyme that catalyzes the first step of tryptophan degradation, could be counteracted by tryptophan. These results advance our knowledge of diverse ISG proteins functioning as antivirals and may provide novel approaches against PIV3. IMPORTANCE: The innate immunity of the host, typified by interferon (IFN), is a major antiviral defense. IFN inhibits virus growth by inducing a large number of IFN-stimulated gene (ISG) proteins, several of which have been shown to have specific antiviral functions. Parainfluenza virus type 3 (PIV3) is major pathogen of children, and no reliable vaccine or specific antiviral against it currently exists. In this article, we report several ISG proteins that strongly inhibit PIV3 growth, the use of which may allow a better antiviral regimen targeting PIV3.
Assuntos
Proteínas de Transporte/imunologia , Interações Hospedeiro-Patógeno , Imunidade Inata , Interferon-alfa/imunologia , Interferon beta/imunologia , Vírus da Parainfluenza 3 Humana/imunologia , Células A549 , Proteínas Adaptadoras de Transdução de Sinal , Animais , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/imunologia , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Células Epiteliais/virologia , Regulação da Expressão Gênica , Células HEK293 , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Indolamina-Pirrol 2,3,-Dioxigenase/imunologia , Interferon-alfa/genética , Interferon beta/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Vírus da Parainfluenza 3 Humana/crescimento & desenvolvimento , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Proteínas/genética , Proteínas/imunologia , Proteínas de Ligação a RNA , Transdução de Sinais , Triptofano/farmacologia , eIF-2 Quinase/genética , eIF-2 Quinase/imunologiaRESUMO
BACKGROUND: Interferon (IFN) inhibits viruses by inducing several hundred cellular genes, aptly named 'interferon (IFN)-stimulated genes' (ISGs). The only two RNA viruses of the Pneumovirus genus of the Paramyxoviridae family, namely Respiratory Syncytial Virus (RSV) and Pneumonia Virus of Mice (PVM), each encode two nonstructural (NS) proteins that share no sequence similarity but yet suppress IFN. Since suppression of IFN underlies the ability of these viruses to replicate in the host cells, the mechanism of such suppression has become an important area of research. This Short Report is an important extension of our previous efforts in defining this mechanism. RESULTS: We show that, like their PVM counterparts, the RSV NS proteins also target multiple members of the ISG family. While significantly extending the substrate repertoire of the RSV NS proteins, these results, unexpectedly, also reveal that the target preferences of the NS proteins of the two viruses are entirely different. This is surprising since the two Pneumoviruses are phylogenetically close with similar genome organization and gene function, and the NS proteins of both also serve as suppressors of host IFN response. CONCLUSION: The finding that the NS proteins of the two highly similar viruses suppress entirely different members of the ISG family raises intriguing questions of pneumoviral NS evolution and mechanism of action.
Assuntos
Vírus da Pneumonia Murina/fisiologia , Vírus Sincicial Respiratório Humano/fisiologia , Proteínas não Estruturais Virais/metabolismo , Animais , Antivirais/antagonistas & inibidores , Variação Genética , Células HEK293 , Interações Hospedeiro-Patógeno/genética , Humanos , Interferons/antagonistas & inibidores , Camundongos , Especificidade por Substrato , Proteínas não Estruturais Virais/genéticaRESUMO
OBJECTIVE: Hippocampal demyelination, a common feature of postmortem multiple sclerosis (MS) brains, reduces neuronal gene expression and is a likely contributor to the memory impairment that is found in >40% of individuals with MS. How demyelination alters neuronal gene expression is unknown. METHODS: To explore whether loss of hippocampal myelin alters expression of neuronal microRNAs (miRNAs), we compared miRNA profiles from myelinated and demyelinated hippocampi from postmortem MS brains and performed validation studies. RESULTS: A network-based interaction analysis depicts a correlation between increased neuronal miRNAs and decreased neuronal genes identified in our previous study. The neuronal miRNA miR-124 was increased in demyelinated MS hippocampi and targets mRNAs encoding 26 neuronal proteins that were decreased in demyelinated hippocampus, including the ionotrophic glutamate receptors AMPA2 and AMPA3. Hippocampal demyelination in mice also increased miR-124, reduced expression of AMPA receptors, and decreased memory performance in water maze tests. Remyelination of the mouse hippocampus reversed these changes. INTERPRETATION: We establish here that myelin alters neuronal gene expression and function by modulating the levels of the neuronal miRNA miR-124. Inhibition of miR-124 in hippocampal neurons may provide a therapeutic approach to improve memory performance in MS patients.
Assuntos
Doenças Desmielinizantes/patologia , Regulação da Expressão Gênica/fisiologia , Hipocampo/patologia , Transtornos da Memória/patologia , MicroRNAs/metabolismo , Neurônios/metabolismo , Receptores de AMPA/metabolismo , Animais , Cuprizona/toxicidade , Doenças Desmielinizantes/etiologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Humanos , Imunossupressores/toxicidade , Transtornos da Memória/etiologia , Camundongos , MicroRNAs/genética , Inibidores da Monoaminoxidase/toxicidade , Esclerose Múltipla/induzido quimicamente , Esclerose Múltipla/complicações , Esclerose Múltipla/patologia , Mudanças Depois da Morte , RNA Mensageiro/metabolismo , Receptores de AMPA/genética , Sirolimo/toxicidadeRESUMO
OBJECTIVE: Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the human central nervous system. Although the clinical impact of gray matter pathology in MS brains is unknown, 30 to 40% of MS patients demonstrate memory impairment. The molecular basis of this memory dysfunction has not yet been investigated in MS patients. METHODS: To investigate possible mechanisms of memory impairment in MS patients, we compared morphological and molecular changes in myelinated and demyelinated hippocampi from postmortem MS brains. RESULTS: Demyelinated hippocampi had minimal neuronal loss but significant decreases in synaptic density. Neuronal proteins essential for axonal transport, synaptic plasticity, glutamate neurotransmission, glutamate homeostasis, and memory/learning were significantly decreased in demyelinated hippocampi, but not in demyelinated motor cortices from MS brains. INTERPRETATION: Collectively, these data support hippocampal demyelination as a cause of synaptic alterations in MS patients and establish that the neuronal genes regulated by myelination reflect specific functions of neuronal subpopulations.
Assuntos
Axônios/patologia , Hipocampo/patologia , Esclerose Múltipla/patologia , Bainha de Mielina/patologia , Fibras Nervosas Mielinizadas/patologia , Sinapses/patologia , Transporte Axonal/fisiologia , Axônios/fisiologia , Western Blotting , Expressão Gênica , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Humanos , Memória/fisiologia , Esclerose Múltipla/metabolismo , Esclerose Múltipla/fisiopatologia , Bainha de Mielina/fisiologia , Fibras Nervosas Mielinizadas/fisiologia , Neurônios/patologia , Neurônios/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/metabolismo , Receptores de Glutamato/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sinapses/fisiologia , Proteínas Vesiculares de Transporte de Glutamato/metabolismoRESUMO
We report the identification of a novel 12 bp deletion of the pre-mRNA splicing gene PRPF31 in a large Chinese family with autosomal dominant retinitis pigmentosa (adRP). This mutation results in the deletion of four amino acids (DeltaH(111)K(112)F(113)I(114)) including H(111), an amino acid residue that is highly conserved throughout evolution. The 12 bp deletion co-segregates with the disease phenotype in 19 RP patients in the family, but is not present in unaffected relatives or 100 normal individuals. Our data indicate that the novel 12 bp deletion in PRPF31 causes retinitis pigementosa in this Chinese adRP family. In contrast to the incomplete penetrance observed in most adRP families linked to chromosome band 19q13.4 (RP11), the 12 bp PRPF31 deletion identified in this study appears to show high penetrance. These data expand the spectrum of PRPF31 mutations causing adRP, and confirm the role of PRPF31 in the pathogenesis of RP.