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1.
Cerebellum ; 17(5): 507-516, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29574551

RESUMEN

Chronic spontaneous urticaria (CSU) is a common itchy skin disease. Despite its prevalence, the neuropathology of CSU is uncertain. In this study, we explored resting state functional connectivity (rs-FC) changes in CSU, as well as how the symptom changes following intervention can modulate rs-FC. Forty patients and 40 healthy controls (HCs) were recruited. Following an intervention, 32 patients participated in a second scan approximately 6 weeks after the first scan. Compared with healthy controls, CSU subjects exhibited higher regional homogeneity (ReHo) values in the cerebellum, which were positively associated with urticaria activity scores over 7 days (UAS7) at baseline. After an intervention accompanied with clinical improvement, we found that ReHo values decreased at the cerebellum and increased at the bilateral primary somatosensory cortex (SI)/primary motor cortex (MI)/supplementary motor area (SMA). Using the cerebellum as a seed, CSU subjects exhibited increased rs-FC with reward regions when compared with HCs and exhibited decreased rs-FC at the right orbitofrontal cortex and right sensorimotor region following the intervention. The improvement rate values were positively associated with reduced rs-FC values in the two regions. Using the cluster of SI/MI/SMA as a seed, CSU patients exhibited decreased rs-FC with the left putamen, caudate, accumbens, and thalamus following the intervention. These results demonstrate the altered cerebellar activity and cerebellum-reward-sensorimotor loops in CSU.


Asunto(s)
Cerebelo/fisiopatología , Corteza Motora/fisiopatología , Corteza Somatosensorial/fisiopatología , Urticaria/fisiopatología , Urticaria/terapia , Acupuntura , Adulto , Mapeo Encefálico , Cerebelo/diagnóstico por imagen , Terapia Combinada , Femenino , Antagonistas de los Receptores Histamínicos H1/uso terapéutico , Humanos , Imagen por Resonancia Magnética , Masculino , Corteza Motora/diagnóstico por imagen , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Descanso , Recompensa , Índice de Severidad de la Enfermedad , Corteza Somatosensorial/diagnóstico por imagen , Resultado del Tratamiento , Urticaria/diagnóstico por imagen
2.
Sci Rep ; 8(1): 1725, 2018 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-29379058

RESUMEN

The brain has long been known to be the regulation center of itch, but the neuropathology of chronic itch, such as chronic spontaneous urticaria (CSU), remains unclear. Thus, we aimed to explore the brain areas involved in the pathophysiology of CSU in hopes that our results may provide valuable insights into the treatment of chronic itch conditions. 40 CSU patients and 40 healthy controls (HCs) were recruited. Urticaria activity scores 7 (UAS7) were collected to evaluate patient's clinical symptoms. Amplitude of low frequency fluctuations (ALFF), voxel-based morphometry (VBM), and seed-based resting-state functional connectivity (rs-FC) analysis were used to assess brain activity and related plasticity. Compared with HCs, CSU patients exhibited 1) higher ALFF values in the right ventral striatum / putamen, which were positively associated with clinical symptoms as measured by UAS7; 2) gray matter volume (GMV) increase in the right ventral striatum and putamen; and 3) decreased rs-FC between the right ventral striatum and the right occipital cortex and between the right putamen and the left precentral gyrus. Using multiple-modality brain imaging tools, we demonstrated the dysfunction of the striatum in CSU. Our results may provide valuable insights into the neuropathology and development of chronic itch.


Asunto(s)
Prurito/fisiopatología , Putamen/patología , Urticaria/patología , Estriado Ventral/patología , Adulto , Enfermedad Crónica , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Putamen/diagnóstico por imagen , Estriado Ventral/diagnóstico por imagen
3.
Virology ; 497: 53-58, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27423269

RESUMEN

Xenotropic/polytropic mouse leukemia viruses (X/P-MLVs) use the XPR1 gammaretrovirus receptor for entry. X/P-MLV host range is defined by usage of naturally occurring restrictive XPR1 receptors, and is governed by polymorphisms in the virus envelope glycoprotein and in XPR1. Here, we examined receptors of four mammalian species permissive to all X/P-MLVs (Mus dunni, human, rabbit, mink). Interference assays showed the four to be functionally distinct. Preinfection with X-MLVs consistently blocked all nine XPR1-dependent viruses, while preinfection with P-MLVs and wild mouse X/P-MLVs produced distinctive interference patterns in the four cells. These patterns indicate shared usage of independent, but not always fully functional, receptor sites. XPR1 sequence comparisons identified candidate sites in receptor-determining regions that correlate with some interference patterns. The evolutionary record suggests that the X/P-MLV tropism variants evolved to adapt to host receptor polymorphisms, to circumvent blocks by competing viruses or to avoid host-encoded envelope glycoproteins acquired for defense.


Asunto(s)
Gammaretrovirus/fisiología , Receptores Acoplados a Proteínas G/metabolismo , Receptores Virales/metabolismo , Infecciones por Retroviridae/virología , Interferencia Viral , Tropismo Viral , Secuencia de Aminoácidos , Animales , Evolución Biológica , Células Cultivadas , Humanos , Ratones , Visón , Polimorfismo Genético , Conejos , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/genética , Receptores Virales/química , Receptores Virales/genética , Especificidad de la Especie , Receptor de Retrovirus Xenotrópico y Politrópico
4.
Zhongguo Zhong Yao Za Zhi ; 40(7): 1415-8, 2015 Apr.
Artículo en Chino | MEDLINE | ID: mdl-26281572

RESUMEN

The clinical study was conducted to further evaluation the effectiveness and safety of Fangfeng Tongsheng granule in the treatment of sub-acute eczema (superficial cold and interior heat syndrome, exterior and interior sthenic syndrome). In the block randomized, multi-centered study, totally 108 patients were enrolled and assigned to two groups: 72 patients in the test group and 36 patients in the placebo control group. Those in the test group took Fangfeng Tongsheng granule with the dose of 3 g, twice a day, while those in the control group were give simulated agent granules with the same dose. The therapeutic course lasted for 14 days. Their efficacies in TCM syndrome, dermal symptoms and adverse events were observed. According to the test results, except for the one exit case, all of the remaining 108 cases, including 71 in the test group, and 36 in the control group, completed the clinical trial. As for the efficacy of TCM syndrome, after the medication for 2 weeks, the cure rate was 33.81% (24/71) in the test group and 0% (0/36) in the control group (P < 0.01), with a statistical difference between the two groups. Regarding the TCM score, after the medication for 2 weeks, the test group decreased by (12.82 +/- 7.96), while the control group decreased by (3.67 +/- 4.12), indicating a statistical difference between the two groups. As for the efficacy of dermal symptoms, after the medication for 2 weeks, the cure rate was 25.35% (18/71) in the test group and 0% (0/36) in the control group, with a statistical difference between the two groups. Regarding the dermal symptom score, after the medication for 2 weeks., the test group decreased by (10.04 +/- 7.17), while the control group decreased by (2.33 +/- 3.57), indicating a statistical difference between the two groups. There was no significant adverse event caused by Fangfeng Tongsheng granule. In conclusion, Fangfeng Tongsheng granule was effective and safe in treating subcute eczema (superficial cold and interior heat syndrome, exterior and interior sthenic syndrome).


Asunto(s)
Medicamentos Herbarios Chinos/administración & dosificación , Eccema/tratamiento farmacológico , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fitoterapia , Resultado del Tratamiento , Adulto Joven
5.
Artículo en Inglés | MEDLINE | ID: mdl-25834623

RESUMEN

Objective. To evaluate the efficacy and safety of herbal ointment, Shi Du Ruan Gao, in patients with plaque-type psoriasis. Design. Single-center, randomized, investigator-blinded, parallel group, placebo-controlled study. Participants. One hundred outpatients with mild to moderate chronic plaque-type psoriasis were enrolled. Intervention. The patients applied either Shi Du Ruan Gao ointment or vehicle ointment topically to for 8 weeks. Main Outcome Measures. The outcomes were assessed using the following criteria: Total Severity Score (TSS, sum of erythema, scaling, and plaque elevation/induration, on a 0 to 4 scale), Investigator Global Assessment (IGA) evaluated on a 0 (Clear) to 4 (s to very severe) scale, and Global Subjects' Assessment of treatment response on a 7-point scale from -1 (worse) to 5 (Cleared). Results. Significant reductions in the Total Severity Score (P < 0.001) (mean score: 2.7 after Shi Du Ruan Gao treatment versus 5.1 in control subjects). Both Investigator Global Assessment (IGA) and Global Subjects' Assessment of treatment are better in the Shi Du Ruan Gao group than the control group (P < 0.001). Conclusion. Shi Du Ruan Gao ointment was a safe, and effective therapy for plaque-type psoriasis.

6.
J Virol ; 84(22): 11970-80, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20844050

RESUMEN

Genetic conflicts between retroviruses and their receptors result in the evolution of novel host entry restrictions and novel virus envelopes, and such variants can influence trans-species transmission. We screened rodents and other mammals for sequence variation in the Xpr1 receptor for the mouse xenotropic or polytropic mouse leukemia viruses (X-MLVs or P-MLVs, respectively) of the gammaretrovirus family and for susceptibility to mouse-derived X/P-MLVs and to XMRV (xenotropic murine leukemia virus-related virus), an X-MLV-like virus isolated from humans with prostate cancer and chronic fatigue syndrome. We identified multiple distinct susceptibility phenotypes; these include the four known Xpr1 variants in Mus and a novel fifth Xpr1 gene found in Mus molossinus and Mus musculus. We describe the geographic and species distribution of the Mus Xpr1 variants but failed to find the X-MLV-restrictive laboratory mouse allele in any wild mouse. We used mutagenesis and phylogenetic analysis to evaluate the functional contributions made by constrained, variable, and deleted residues. Rodent Xpr1 is under positive selection, indicating a history of host-pathogen conflicts; several codons under selection have known roles in virus entry. All non-Mus mammals are susceptible to mouse X-MLVs, but some restrict other members of the X/P-MLV family, and the resistance of hamster and gerbil cells to XMRV indicates that XMRV has unique receptor requirements. We show that the hypervariable fourth extracellular XPR1 loop (ECL4) contains three evolutionarily constrained residues that do not contribute to receptor function, we identify two novel residues important for virus entry (I579 and T583), and we describe a unique pattern of ECL4 variation in the three virus-restrictive Xpr1 variants found in MLV-infected house mice; these mice carry different deletions in ECL4, suggesting either that these sites or loop size affects receptor function.


Asunto(s)
Evolución Molecular , Gammaretrovirus/fisiología , Variación Genética , Virus de la Leucemia Murina/fisiología , Mamíferos/genética , Receptores Acoplados a Proteínas G/genética , Receptores Virales/genética , Infecciones por Retroviridae/genética , Infecciones por Retroviridae/veterinaria , Secuencia de Aminoácidos , Animales , Bovinos , Cricetinae , Perros , Gammaretrovirus/clasificación , Gammaretrovirus/genética , Gammaretrovirus/aislamiento & purificación , Cabras , Cobayas , Humanos , Virus de la Leucemia Murina/clasificación , Virus de la Leucemia Murina/genética , Virus de la Leucemia Murina/aislamiento & purificación , Mamíferos/metabolismo , Mamíferos/virología , Ratones , Datos de Secuencia Molecular , Filogenia , Conejos , Receptores Acoplados a Proteínas G/metabolismo , Receptores Virales/metabolismo , Infecciones por Retroviridae/metabolismo , Infecciones por Retroviridae/virología , Alineación de Secuencia , Receptor de Retrovirus Xenotrópico y Politrópico
7.
PLoS Pathog ; 6: e1000974, 2010 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-20617165

RESUMEN

Mouse APOBEC3 (mA3) is a cytidine deaminase with antiviral activity. mA3 is linked to the Rfv3 virus resistance factor, a gene responsible for recovery from infection by Friend murine leukemia virus, and mA3 allelic variants differ in their ability to restrict mouse mammary tumor virus. We sequenced mA3 genes from 38 inbred strains and wild mouse species, and compared the mouse sequence and predicted structure with human APOBEC3G (hA3G). An inserted sequence was identified in the virus restrictive C57BL strain allele that disrupts a splice donor site. This insertion represents the long terminal repeat of the xenotropic mouse gammaretrovirus, and was acquired in Eurasian mice that harbor xenotropic retrovirus. This viral regulatory sequence does not alter splicing but is associated with elevated mA3 expression levels in spleens of laboratory and wild-derived mice. Analysis of Mus mA3 coding sequences produced evidence of positive selection and identified 10 codons with very high posterior probabilities of having evolved under positive selection. Six of these codons lie in two clusters in the N-terminal catalytically active cytidine deaminase domain (CDA), and 5 of those 6 codons are polymorphic in Rfv3 virus restrictive and nonrestrictive mice and align with hA3G CDA codons that are critical for deaminase activity. Homology models of mA3 indicate that the two selected codon clusters specify residues that are opposite each other along the predicted CDA active site groove, and that one cluster corresponds to an hAPOBEC substrate recognition loop. Substitutions at these clustered mA3 codons alter antiviral activity. This analysis suggests that mA3 has been under positive selection throughout Mus evolution, and identified an inserted retroviral regulatory sequence associated with enhanced expression in virus resistant mice and specific residues that modulate antiviral activity.


Asunto(s)
Citidina Desaminasa/genética , Desaminasa APOBEC-3G , Secuencia de Aminoácidos , Animales , Animales Salvajes/genética , Antirretrovirales/química , Secuencia de Bases , Evolución Molecular , Humanos , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Insercional , Selección Genética , Homología de Secuencia de Ácido Nucleico
8.
Retrovirology ; 6: 87, 2009 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-19811656

RESUMEN

BACKGROUND: The evolutionary interactions between retroviruses and their receptors result in adaptive selection of restriction variants that can allow natural populations to evade retrovirus infection. The mouse xenotropic/polytropic (X/PMV) gammaretroviruses rely on the XPR1 cell surface receptor for entry into host cells, and polymorphic variants of this receptor have been identified in different rodent species. RESULTS: We screened a panel of X/PMVs for infectivity on rodent cells carrying 6 different XPR1 receptor variants. The X/PMVs included 5 well-characterized laboratory and wild mouse virus isolates as well as a novel cytopathic XMV-related virus, termed Cz524, isolated from an Eastern European wild mouse-derived strain, and XMRV, a xenotropic-like virus isolated from human prostate cancer. The 7 viruses define 6 distinct tropisms. Cz524 and another wild mouse isolate, CasE#1, have unique species tropisms. Among the PMVs, one Friend isolate is restricted by rat cells. Among the XMVs, two isolates, XMRV and AKR6, differ from other XMVs in their PMV-like restriction in hamster cells. We generated a set of Xpr1 mutants and chimeras, and identified critical amino acids in two extracellular loops (ECLs) that mediate entry of these different viruses, including 3 residues in ECL3 that are involved in PMV entry (E500, T507, and V508) and can also influence infectivity by AKR6 and Cz524. CONCLUSION: We used a set of natural variants and mutants of Xpr1 to define 6 distinct host range variants among naturally occurring X/PMVs (2 XMV variants, 2 PMVs, 2 different wild mouse variants). We identified critical amino acids in XPR1 that mediate entry of these viruses. These gammaretroviruses and their XPR1 receptor are thus highly functionally polymorphic, a consequence of the evolutionary pressures that favor both host resistance and virus escape mutants. This variation accounts for multiple naturally occurring virus resistance phenotypes and perhaps contributes to the widespread distribution of these viruses in rodent and non-rodent species.


Asunto(s)
Gammaretrovirus/fisiología , Receptores Acoplados a Proteínas G/fisiología , Receptores Virales/fisiología , Tropismo Viral , Secuencia de Aminoácidos , Animales , Línea Celular , Cricetinae , Gammaretrovirus/genética , Ratones , Visón , Datos de Secuencia Molecular , Ratas , Alineación de Secuencia , Receptor de Retrovirus Xenotrópico y Politrópico
9.
Virology ; 391(2): 232-9, 2009 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-19584017

RESUMEN

Three N-linked glycosylation sites were removed from the envelope glycoproteins of Friend, Moloney, and AKV mouse ecotropic gammaretroviruses: gs1 and gs2, in the receptor binding domain; and gs8, in a region implicated in post-binding cell fusion. Mutants were tested for their ability to infect rodent cells expressing 4 CAT-1 receptor variants. Three mutants (Mo-gs1, Mo-gs2, and Fr-gs1) infect NIH 3T3 and rat XC cells, but are severely restricted in Mus dunni cells and Lec8, a Chinese hamster cell line susceptible to ecotropic virus. This restriction is reproduced in ferret cells expressing M. dunni dCAT-1, but not in cells expressing NIH 3T3 mCAT-1. Virus binding assays, pseudotype assays, and the use of glycosylation inhibitors further suggest that restriction is primarily due to receptor polymorphism and, in M. dunni cells, to glycosylation of cellular proteins. Virus envelope glycan size or type does not affect infectivity. Thus, host range variation due to N-glycan deletion is receptor variant-specific, cell-specific, virus type-specific, and glycan site-specific.


Asunto(s)
Virus de la Leucemia Murina/fisiología , Proteínas del Envoltorio Viral/metabolismo , Acoplamiento Viral , Sustitución de Aminoácidos , Animales , Línea Celular , Cricetinae , Cricetulus , Hurones , Virus de la Leucemia Murina de Friend/fisiología , Glicosilación , Ratones , Virus de la Leucemia Murina de Moloney/fisiología , Mutagénesis Sitio-Dirigida , Ratas
10.
Artículo en Chino | MEDLINE | ID: mdl-19317047

RESUMEN

OBJECTIVE: To evaluate the effect of combined herbal medicine therapy on the expression of psoriasis-associated antigen (Pso p27) in patients with psoriasis vulgaris. METHODS: Fifteen psoriasis vulgaris patients were included in the study and they were all treated with combined herbal medicine therapy for 12 weeks. Both psoriasis area and severity index (PASI) score and plaque index (PI) score were evaluated before and after treatment, while skin biopsies from selected lesions and uninvolved skin near the lesions were performed. Expression of Pso p27 in the target skin and surrounding uninjured skins were analysed using immunofluorescence method. RESULTS: The PASI score and PI score decreased after the combined herbal medicine therapy in both acute and silent stages (P < 0.01), so did the positive cells of Pso p27 and the intensity of fluorescein stain (P < 0.05). CONCLUSION: The combined herbal medicine therapy is effective in treating psoriasis vulgaris in both acute and silent stages, which may be resulted from its inhibition of the expression of Pso p27.


Asunto(s)
Antígenos/inmunología , Medicamentos Herbarios Chinos/uso terapéutico , Fitoterapia , Psoriasis/tratamiento farmacológico , Psoriasis/inmunología , Adulto , Anciano , Quimioterapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psoriasis/patología , Adulto Joven
11.
Proc Natl Acad Sci U S A ; 106(9): 3259-63, 2009 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-19221034

RESUMEN

The Fv1 virus resistance gene is a coopted endogenous retrovirus (ERV) sequence related to the gag gene of the MuERV-L ERV family. Three major Fv1 resistance alleles have been identified in laboratory mice, and they target virus capsid genes to produce characteristic patterns of resistance to mouse leukemia viruses (MLVs). We identified Fv1 in 3 of the 4 Mus subgenera; its absence from Coelomys and 1 of 3 species of Pyromys indicate Fv1 was acquired shortly after the origin of the Mus genus. We sequenced Fv1 genes from 21 mice representative of the major taxonomic groups of Mus. Two lines of evidence indicate that Fv1 has had antiviral function for 7 million years of evolution. First, 2 species of African pygmy mice (subgenus Nannomys) show an Fv1-like MLV resistance, and transduced cells expressing the Nannomys Fv1 gene reproduce this resistance pattern. Second, sequence comparisons suggest that Fv1 has been involved in genetic conflicts throughout Mus evolution. We found evidence for strong positive selection of Fv1 and identified 6 codons that show evidence of positive selection: 3 codons in the C-terminal region including 2 previously shown to contribute to Fv1 restriction in laboratory mice, and 3 codons in a 10-codon segment overlapping the major homology region of Fv1; this segment is known to be involved in capsid multimerization. This analysis suggests that Fv1 has had an antiviral role throughout Mus evolution predating exposure of mice to the MLVs restricted by laboratory mouse Fv1, and suggests a mechanism for Fv1 restriction.


Asunto(s)
Evolución Molecular , Gammaretrovirus/genética , Filogenia , Proteínas/genética , Proteínas/metabolismo , Selección Genética , Alelos , Secuencia de Aminoácidos , Animales , Ratones , Datos de Secuencia Molecular , Proteínas/química , Infecciones por Retroviridae/genética , Infecciones por Retroviridae/metabolismo , Infecciones por Retroviridae/virología , Alineación de Secuencia , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/metabolismo , Infecciones Tumorales por Virus/virología
12.
J Virol ; 82(13): 6120-9, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18417580

RESUMEN

Cells of Mus minutoides, an African pygmy mouse of the subgenus Nannomys, are susceptible to ecotropic Moloney and Friend mouse leukemia viruses (MLVs) but not to AKV-type MLVs. Transfected MA139 ferret cells expressing the mCAT-1 cell surface receptor, with the minCAT-1 substitutions K222Q and V233L, did not restrict AKV MLV. The resistance of M. minutoides cells to AKV MLV was not relieved by inhibitors of glycosylation or by the introduction of NIH 3T3 mCAT-1. Resistance is thus not mediated by receptor sequence variation, expression level, or glycosylation. M. minutoides cells are also infectible with LacZ pseudotypes having AKV Env and Moloney MLV (MoMLV) Gag proteins, further indicating that AKV Env sequence variations do not contribute to the observed block. The pattern of virus resistance in M. minutoides differs from that of the known variants of the Fv1 postentry resistance gene; M. minutoides is equally resistant to N-, B-, and NR-tropic AKV viruses and is equally susceptible to NR- and NB-tropic Friend MLVs. This novel resistance blocks replication before reverse transcription, whereas Fv1 generally restricts replication after reverse transcription; M. minutoides cells produce 2-long-terminal-repeat viral DNA circles and linear viral DNA after infection with MoMLV but not with AKV MLV. Analysis of MoMLV-AKV MLV chimeras determined that the target of resistance is in the virus capsid gene. Mutagenesis demonstrated that restriction is mediated by two amino acid substitutions, H117L and A110R; substitutions at these sites can also be targeted by the resistance genes Fv1 and TRIM5alpha. M. minutoides cells thus have a novel postentry resistance to AKV MLVs.


Asunto(s)
Gammaretrovirus/inmunología , Inmunidad Innata/inmunología , Infecciones por Retroviridae/inmunología , Infecciones Tumorales por Virus/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Transportador de Aminoácidos Catiónicos 1/genética , Línea Celular , Productos del Gen gag/genética , Inmunidad Innata/genética , Ratones , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN
13.
Retrovirology ; 5: 2, 2008 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-18186934

RESUMEN

BACKGROUND: We previously identified unusual variants of Moloney and Friend ecotropic mouse gammaretroviruses that have altered host range and are cytopathic in cells of the wild mouse species Mus dunni. Cytopathicity was attributed to different amino acid substitutions at the same critical env residue involved in receptor interaction: S82F in the Moloney variant Spl574, and S84A in the Friend mouse leukemia virus F-S MLV. Because M. dunni cells carry a variant CAT-1 cell surface virus receptor (dCAT-1), we examined the role of this receptor variant in cytopathicity and host range. RESULTS: We expressed dCAT-1 or mCAT-1 of NIH 3T3 origin in cells that are not normally infectible with ecotropic MLVs and evaluated the transfectants for susceptibility to virus infection and to virus-induced syncytium formation. The dCAT-1 transfectants, but not the mCAT-1 transfectants, were susceptible to virus-induced cytopathicity, and this cytopathic response was accompanied by the accumulation of unintegrated viral DNA. The dCAT-1 transfectants, however, did not also reproduce the relative resistance of M. dunni cells to Moloney MLV, and the mCAT-1 transfectants did not show the relative resistance of NIH 3T3 cells to Spl574. Western analysis, use of glycosylation inhibitors and mutagenesis to remove receptor glycosylation sites identified a possible role for cell-specific glycosylation in the modulation of virus entry. CONCLUSION: Virus entry and virus-induced syncytium formation using the CAT-1 receptor are mediated by a small number of critical amino acid residues in receptor and virus Env. Virus entry is modulated by glycosylation of cellular proteins, and this effect is cell and virus-specific.


Asunto(s)
Transportador de Aminoácidos Catiónicos 1/genética , Virus de la Leucemia Murina de Friend/patogenicidad , Células Gigantes/fisiología , Virus de la Leucemia Murina de Moloney/patogenicidad , Polimorfismo Genético , Animales , Animales Salvajes , Transportador de Aminoácidos Catiónicos 1/metabolismo , Línea Celular , Efecto Citopatogénico Viral , Glicosilación , Leucemia Experimental/virología , Ratones , Células 3T3 NIH , Infecciones por Retroviridae/virología , Transfección , Infecciones Tumorales por Virus/virología , Internalización del Virus
14.
J Virol ; 81(19): 10550-7, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17634227

RESUMEN

Mouse xenotropic and polytropic leukemia viruses (XMVs and PMVs) are closely related gammaretroviruses that use the XPR1 receptor for entry. To identify amino acid residues in XPR1 important for virus entry, we tested mouse cells derived from evolutionarily divergent species for susceptibility to prototypical PMVs, XMVs, and the wild mouse isolate CasE#1. CasE#1 has a variant XMV/PMV host range, and sequence analysis of the CasE#1 env gene identifies segments related to PMVs and XMVs. Cells from the Asian mouse species Mus pahari show a unique pattern of susceptibility to these three viruses; these cells are susceptible to XMVs and CasE#1 but are resistant to PMVs, whereas NIH 3T3 cells show the reciprocal pattern, susceptibility to only PMVs. The M. pahari XPR1 gene differs from that of NIH 3T3 in the two extracellular loops (ECLs) previously shown to mediate virus entry (M. Marin, C. S. Tailor, A. Nouri, S. L. Kozak, and D. Kabat, J. Virol. 73:9362-9368, 1999, and N. S. Van Hoeven and A. D. Miller, Retrovirology 2:76, 2005). Using transfected hamster cells expressing chimeric and mutated XPR1s, we demonstrated that the susceptibility differences between NIH 3T3 and M. pahari cells are receptor mediated, that PMV entry requires residues in ECL3, that the CasE#1 entry determinant is in ECL4, and that determinants for XMV entry are in both ECL3 and ECL4. Additional substitutions in ECL3 and ECL4 modulate virus susceptibility and suggest that ECL3 and ECL4 may contribute to the formation of a single virus receptor site. The position of M. pahari at the base of the Mus phylogenetic tree indicates that XPR1-mediated susceptibility to XMVs is the ancestral type in this genus and that the phenotypic variants of mouse XPR1 likely arose in conjunction with exposure to gammaretrovirus infections and coevolutionary adaptations in the viral envelope.


Asunto(s)
Gammaretrovirus/fisiología , Virus de la Leucemia Murina/fisiología , Receptores Acoplados a Proteínas G/fisiología , Receptores Virales/fisiología , Proteínas del Envoltorio Viral/genética , Internalización del Virus , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Quimera , Cricetinae , Genes Virales , Variación Genética , Ratones , Datos de Secuencia Molecular , Células 3T3 NIH , Filogenia , Receptores Acoplados a Proteínas G/genética , Receptores Virales/genética , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/metabolismo , Receptor de Retrovirus Xenotrópico y Politrópico
15.
J Virol ; 79(15): 9677-84, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16014929

RESUMEN

Cells from the Asian wild mouse species Mus castaneus are resistant to infection by the polytropic host range group of mouse gammaretroviruses. Two factors are responsible for this resistance: a defective XPR1 cell surface receptor for polytropic murine leukemia viruses (P-MLVs), and a resistance factor detectable only in interspecies hybrids between M. castaneus and mice with an XPR1 variant that permits infection by xenotropic MLVs (X-MLVs) as well as P-MLVs. This second novel virus resistance phenotype has been associated with expression of viral Env glycoprotein; Northern blotting with specific hybridization probes identified a spliced X-MLV env message unique to virus-resistant mice. These observations suggest that resistance is due to expression of one or more endogenous X-MLV envelope genes that interfere with infection by exogenous P-MLVs. M. castaneus contains multiple X-MLV proviruses, but serial backcrosses reduced this proviral content and permitted identification of a single proviral env sequence inherited with resistance. The resistance phenotype and the provirus were mapped to the same site on distal chromosome 18. The provirus was shown to be a full-length provirus highly homologous to previously described X-MLVs. Use of viral pseudotypes confirmed that this resistance gene, termed Rmcf2, prevents entry of P-MLVs. Rmcf2 resembles the virus resistance genes Fv4 and Rmcf in that it produces Env glycoprotein but fails to produce infectious virus; the proviruses associated with all three resistance genes have fatal defects. This type of provirus Env-mediated resistance represents an important defense mechanism in wild mouse populations exposed to endemic infections.


Asunto(s)
Genes Virales/fisiología , Virus de la Leucemia Murina/genética , Leucemia Experimental/virología , Provirus/genética , Infecciones por Retroviridae/virología , Infecciones Tumorales por Virus/virología , Alelos , Animales , Cromosomas/genética , Cruzamientos Genéticos , Susceptibilidad a Enfermedades , Genes Virales/genética , Genoma , Leucemia Experimental/genética , Ratones , Datos de Secuencia Molecular , Muridae , Receptores Acoplados a Proteínas G , Receptores Virales/genética , Infecciones por Retroviridae/genética , Infecciones Tumorales por Virus/genética , Receptor de Retrovirus Xenotrópico y Politrópico
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