RESUMO
OBJECTIVES: To investigate the effects of an intratympanic injection of dexamethasone combined with gentamicin on the expression level of serum P0 protein antibodies in patients with Meniere's disease (MD). METHODS: A total of 136 patients with MD treated in our hospital were enrolled in this study. Among them, 68 patients were treated with an intratympanic injection of dexamethasone combined with gentamicin (observation group). Another 68 patients were treated with gentamicin alone (control group). RESULTS: After treatment, the expression levels of IgG and IgM in the two groups significantly decreased (p<0.05); the levels in the observation group were significantly lower than those in the control group (p<0.05). The incidences of vertigo, tinnitus, and gait instability in the observation group were significantly lower than those in the control group (p<0.05). Vestibular symptom index (VSI) scores in the observation group were significantly lower than those in the control group (p<0.05). We observed no significant difference between the two groups in the number of vertigo attacks 6 months after treatment (p>0.05). CONCLUSION: For patients with MD, dexamethasone combined with gentamicin can reduce the incidence of vertigo, tinnitus, and gait instability, but it has no effect on the efficacy or number of vertigo attacks 6 months after treatment. Therefore, the levels of myelin P0 protein antibodies after treatment can be used as predictors of vertigo at 6 months after treatment.
Assuntos
Doença de Meniere , Proteína P0 da Mielina , Antibacterianos/uso terapêutico , Dexametasona/uso terapêutico , Gentamicinas/uso terapêutico , Humanos , Injeção Intratimpânica , Doença de Meniere/tratamento farmacológico , Resultado do TratamentoRESUMO
Diagnostic yield of genetic studies for Charcot-Marie-Tooth disease (CMT) is little known, with a lack of epidemiological data to build better diagnostic strategies outside the United States and Europe. We aimed to evaluate the performance of two molecular diagnostic strategies for patients with CMT, and to characterize epidemiological findings of these conditions in southern Brazil. We performed a single-center cross-sectional study, in which 94 patients (55 families) with CMT suspicion were evaluated. Overall, the diagnostic yield of the combined strategy of Multiplex-ligation-dependent-probe-amplification (MLPA) of PMP22/GJB1/MPZ and GJB1/MPZ/PMP22 Sanger sequencing was 63.6% (28/44) for index cases with demyelinating/intermediate CMT suspicion (21 CMT1A-PMP22, 5 CMTX1-GJB1 and 2 with probably CMT1B-MPZ diagnosis). Five of the 11 index cases (45.4%) with axonal CMT had at least a possible diagnosis with next generation sequencing (NGS) panel of 104 inherited neuropathies-related genes (one each with CMT1A-PMP22, CMT2A-MFN2, CMT2K-GDAP1, CMT2U-MARS, CMT2W-HARS1). Detailed clinical, neurophysiological and molecular data of families are provided. Sequential molecular diagnosis strategies with MLPA plus target Sanger sequencing for demyelinating/intermediate CMT had high diagnostic yield, and almost half of axonal CMT families had at least a possible diagnosis with the comprehensive NGS panel. Most frequent subtypes of CMT in our region are CMT1A-PMP22 and CMTX1-GJB1.
Assuntos
Doença de Charcot-Marie-Tooth/diagnóstico , Conexinas/genética , Proteína P0 da Mielina/genética , Proteínas da Mielina/genética , Adulto , Brasil/epidemiologia , Doença de Charcot-Marie-Tooth/classificação , Doença de Charcot-Marie-Tooth/epidemiologia , Doença de Charcot-Marie-Tooth/genética , Feminino , Humanos , Masculino , Reação em Cadeia da Polimerase Multiplex/métodos , Mutação , Patologia Molecular/métodos , Análise de Sequência de DNA , Proteína beta-1 de Junções ComunicantesRESUMO
Virus-like disease symptoms consisting of leaf cupping, shortened internodes, and overall stunting were observed in commercial cotton fields in Alabama in 2017 to 2018. To determine the complete genome sequence of the suspected causal polerovirus, symptomatic leaf samples were collected in Macon County, Alabama, and subjected to Illumina RNA sequencing. Based on BLASTn analysis, the Illumina contig of 5,771 nt shared the highest nucleotide identity (approximately 95%) with members of the species Cotton leafroll dwarf virus (CLRDV) (genus Polerovirus; family Luteoviridae) from Argentina and Brazil. The full-length viral genome sequence was verified by reverse transcription (RT)-PCR amplification, cloning, and Sanger sequencing. The complete CLRDV genome of 5,865 nt in length shared 94.8 to 95.2% nucleotide identity with six previously reported CLRDV isolates. The genome of the CLRDV isolate amplified from Alabama samples (CLRDV-AL) has seven predicted open reading frames (ORFs). Viral proteins 1 to 5 (P1 to P5) shared 91.9 to 99.5% amino acid identity with the six CLRDV isolates from Argentina and Brazil. However, P0, the suppressor of host gene silencing, shared 82.4 to 88.5% pairwise amino acid identity with the latter CLRDV isolates. Phylogenetic analysis of the seven full-length CLRDV genomes resolved three sister clades: CLRDV-AL, CLRDV-typical, and CLRDV-atypical, respectively. Three recombination events were detected by the recombination detection program among the seven CLRDV isolates with breakpoints occurring along the genome. Pairwise nucleotide identity comparisons of ORF0 sequences for the three CLRDV-AL field isolates indicated that they were >99% identical, suggesting that this previously unknown CLRDV genotype represents a single introduction to Alabama.
Assuntos
Luteoviridae , Proteína P0 da Mielina , Brasil , Genótipo , Filogenia , Doenças das Plantas , Estados UnidosRESUMO
OBJECTIVES: To investigate the effects of an intratympanic injection of dexamethasone combined with gentamicin on the expression level of serum P0 protein antibodies in patients with Meniere's disease (MD). METHODS: A total of 136 patients with MD treated in our hospital were enrolled in this study. Among them, 68 patients were treated with an intratympanic injection of dexamethasone combined with gentamicin (observation group). Another 68 patients were treated with gentamicin alone (control group). RESULTS: After treatment, the expression levels of IgG and IgM in the two groups significantly decreased (p<0.05); the levels in the observation group were significantly lower than those in the control group (p<0.05). The incidences of vertigo, tinnitus, and gait instability in the observation group were significantly lower than those in the control group (p<0.05). Vestibular symptom index (VSI) scores in the observation group were significantly lower than those in the control group (p<0.05). We observed no significant difference between the two groups in the number of vertigo attacks 6 months after treatment (p>0.05). CONCLUSION: For patients with MD, dexamethasone combined with gentamicin can reduce the incidence of vertigo, tinnitus, and gait instability, but it has no effect on the efficacy or number of vertigo attacks 6 months after treatment. Therefore, the levels of myelin P0 protein antibodies after treatment can be used as predictors of vertigo at 6 months after treatment.
Assuntos
Humanos , Proteína P0 da Mielina , Doença de Meniere/tratamento farmacológico , Dexametasona/uso terapêutico , Gentamicinas/uso terapêutico , Resultado do Tratamento , Injeção Intratimpânica , Antibacterianos/uso terapêuticoRESUMO
Upper limb nerve injuries are common, and their treatment poses a challenge for physicians and surgeons. Experimental models help in minimum exploration of the functional characteristics of peripheral nerve injuries of forelimbs. This study was conducted to characterize the functional recovery (1, 3, 7, 10, 14, and 21 days) after median and ulnar nerve crush in mice and analyze the histological and biochemical markers of nerve regeneration (after 21 days). Sensory-functional impairments appeared after 1 day. The peripheral nerve morphology, the nerve structure, and the density of myelin proteins [myelin protein zero (P0) and peripheral myelin protein 22 (PMP22)] were analyzed after 21 days. Cold allodynia and fine motor coordination recovery occurred on the 10th day, and grip strength recovery was observed on the 14th day after injury. After 21 days, there was partial myelin sheath recovery. PMP22 recovery was complete, whereas P0 recovery was not. Results suggest that there is complete functional recovery even with partial remyelination of median and ulnar nerves in mice.
Assuntos
Nervo Mediano/fisiopatologia , Recuperação de Função Fisiológica , Remielinização , Nervo Ulnar/fisiopatologia , Animais , Masculino , Nervo Mediano/lesões , Nervo Mediano/metabolismo , Camundongos , Proteína P0 da Mielina/metabolismo , Proteínas da Mielina/metabolismo , Compressão Nervosa , Nervo Ulnar/lesões , Nervo Ulnar/metabolismoRESUMO
Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Genetic factors associated with immune response contribute to infection development and disease. M. leprae has the capacity to invade Schwann cells in the peripheral nervous system and cause neuropathy. However, while the responsible molecular mechanisms remain to be fully unveiled, they have begun being elucidated. We studied genetic variants Myelin Protein Zero (MPZ), a major structural component of the myelin sheath, and Mannose Binding Lectin 2 (MBL2), a protein involved in immune response, in 112 family groups of 114 leprosy patients using PCR-RFLP, aiming to calculate the association and allelic transmission of variants associated in first, second and third-degree relatives. Polymorphisms found in MPZ and MBL2 showed association with leprosy. Different probabilities for allelic transmission were found for first and second-degree relatives, a fact that is important to take into account when evaluating risk in contacts of leprosy patients. Structural analysis allows the study of putative amino acids and their possible effect on protein structure and function, as well as on the assembly of a protein homotetramer. Our results suggest that the identified MPZ and MBL2 gene mutations are associated with leprosy in a Colombian population, which correlates with MPZ and MBL2 protein function, and increase the risk of M. leprae infection in leprosy-patients' family members. Additionally, structural analyses were carried out specifically for MPZ protein using information available in databases, and analyzing the substitutions in wildtype and mutant protein. The results show significant structural changes, which may be associated to infection and pathogenicity.
Assuntos
Hanseníase , Lectina de Ligação a Manose , Proteína P0 da Mielina , Adulto , Colômbia , Feminino , Humanos , Hanseníase/genética , Hanseníase/imunologia , Masculino , Lectina de Ligação a Manose/química , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Pessoa de Meia-Idade , Modelos Moleculares , Proteína P0 da Mielina/química , Proteína P0 da Mielina/genética , Proteína P0 da Mielina/imunologia , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Inferior alveolar nerve (IAN) injuries may occur during various dental routine procedures, especially in the removal of impacted lower third molars, and nerve recovery in these cases is a great challenge in dentistry. Here, the IAN crush injury model was used to assess the efficacy of photobiomodulation (PBM) in the recovery of the IAN in rats following crushing injury (a partial lesion). Rats were divided into four experimental groups: without any procedure, IAN crush injury, and IAN crush injury with PBM and sham group with PBM. Treatment was started 2 days after surgery, above the site of injury, and was performed every other day, totaling 10 sessions. Rats were irradiated with GaAs Laser (Gallium Arsenide, Laserpulse, Ibramed Brazil) emitting a wavelength of 904 nm, an output power of 70 mWpk, beam spot size at target â¼0.1 cm2, a frequency of 9500 Hz, a pulse time 60 ns, and an energy density of 6 J/cm2. Nerve recovery was investigated by measuring the morphometric data of the IAN using TEM and by the expression of laminin, neurofilaments (NFs), and myelin protein zero (MPZ) using Western blot analysis. We found that IAN-injured rats which received PBM had a significant improvement of IAN morphometry when compared to IAN-injured rats without PBM. In parallel, all MPZ, laminin, and NFs exhibited a decrease after PBM. The results of this study indicate that the correlation between the peripheral nerve ultrastructure and the associated protein expression shows the beneficial effects of PBM.
Assuntos
Terapia com Luz de Baixa Intensidade , Nervo Mandibular/metabolismo , Nervo Mandibular/patologia , Compressão Nervosa , Neuropeptídeos/metabolismo , Animais , Densitometria , Filamentos Intermediários/metabolismo , Laminina/metabolismo , Masculino , Nervo Mandibular/ultraestrutura , Proteína P0 da Mielina/metabolismo , Ratos WistarRESUMO
Neurotrophins are crucial in relation to axonal regrowth and remyelination following injury; and neural mobilization (NM) is a noninvasive therapy that clinically is effective in neuropathic pain treatment, but its mechanisms remains unclear. We examined the effects of NM on the regeneration of sciatic nerve after chronic constriction injury (CCI) in rats. The CCI was performed on adult male rats, submitted to 10 sessions of NM, starting 14 days after CCI. Then, the nerves were analyzed using transmission electron microscopy and western blot for neural growth factor (NGF) and myelin protein zero (MPZ). We observed an increase of NGF and MPZ after CCI and NM. Electron microscopy revealed that CCI-NM samples had high numbers of axons possessing myelin sheaths of normal thickness and less inter-axonal fibrosis than the CCI. These data suggest that NM is effective in facilitating nerve regeneration and NGF and MPZ are involved in this effect.
Assuntos
Manipulações Musculoesqueléticas , Proteína P0 da Mielina/metabolismo , Fator de Crescimento Neural/metabolismo , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/metabolismo , Animais , Axônios/metabolismo , Axônios/ultraestrutura , Masculino , Proteína P0 da Mielina/genética , Fator de Crescimento Neural/genética , Traumatismos dos Nervos Periféricos/terapia , Ratos , Ratos Wistar , Nervo Isquiático/lesões , Nervo Isquiático/metabolismo , Nervo Isquiático/fisiologiaRESUMO
The p.Thr124Met mutation in the myelin protein zero (MPZ) causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers´ sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch), the founder effect hypothesis for this allele migration is suggestive. Rev. Biol. Trop. 62 (4): 1285-1293. Epub 2014 December 01.
La mutación p.thr124Met en la proteína mielina cero (MPZ) causa la enfermedad de Charcot-Marie-Tooth tipo 2J, una neuropatía periférica con síntomas adicionales como alteraciones pupilares y sordera. Se ha observado en varias familias alrededor del mundo, originarias de Alemania, Bélgica, Japón, Italia y Norteamérica, entre otras. Aquí reportamos a pacientes centroamericanos provenientes de Costa Rica que acarrean esta mutación. Se realizaron análisis clínico, electrofisiológico y molecular de pacientes y controles, incluyendo secuenciación del gen y de marcadores ligados a éste. Estos pacientes comparten casi por completo el haplotipo con dos pacientes belgas no emparentados. Como resultado del análisis de los haplotipos, basado en diez marcadores (siete SNPs, dos microsatélites y un elemento poli-A intrónico), se sugiere que se ha dado un efecto fundador en la migración de este alelo.
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Doença de Charcot-Marie-Tooth/genética , Perda Auditiva Neurossensorial/genética , Proteína P0 da Mielina/genética , Mutação Puntual/genética , Estudos de Casos e Controles , Costa Rica , Doença de Charcot-Marie-Tooth/etnologia , Efeito Fundador , Haplótipos , Perda Auditiva Neurossensorial/etnologia , LinhagemRESUMO
The p.Thr124Met mutation in the myelin protein zero (MPZ) causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers' sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch), the founder effect hypothesis for this allele migration is suggestive.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Perda Auditiva Neurossensorial/genética , Proteína P0 da Mielina/genética , Mutação Puntual/genética , Adulto , Idoso , Estudos de Casos e Controles , Doença de Charcot-Marie-Tooth/etnologia , Costa Rica , Feminino , Efeito Fundador , Haplótipos , Perda Auditiva Neurossensorial/etnologia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Adulto JovemRESUMO
Schwann cells play pivotal roles in the development and maintenance of the peripheral nervous system. Here, we show that intact sciatic nerve axons of mice contain a small population of ribosomes, which increases by several orders of magnitude when axons are desomatized (severed from their cell bodies). We furthermore demonstrate, using the Wallerian degeneration slow mouse as a model, that Schwann cells transfer polyribosomes to desomatized axons. These data indicate that Schwann cells have the propensity to control axonal protein synthesis by supplying ribosomes on local basis.
Assuntos
Axônios/fisiologia , Neuroglia/citologia , Ribossomos/metabolismo , Células de Schwann/fisiologia , Animais , Axônios/ultraestrutura , Transporte Biológico/genética , Modelos Animais de Doenças , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Microscopia Eletrônica de Transmissão/métodos , Proteína Básica da Mielina/metabolismo , Proteína P0 da Mielina/metabolismo , Proteínas do Tecido Nervoso/genética , Neuroglia/fisiologia , Polirribossomos/metabolismo , Neuropatia Ciática/genética , Neuropatia Ciática/patologia , Neuropatia Ciática/fisiopatologia , Transfecção/métodosRESUMO
BACKGROUND AND OBJECTIVE: The periodontal ligament is a specialized connective tissue, derived from dental follicle and originated from neural crest cells. Recently it has been suggested, based on animal models, that periodontal ligament could be a niche for neural crest stem cells. However, there is still little knowledge on this subject. The identification of neural crest adult stem cells has received much attention based on its potential in tissue regeneration. The objective of the present work was to verify the human periodontal ligament as a niche for neural crest stem cells. MATERIAL AND METHODS: Cells from human periodontal ligament were isolated from 10 teeth of seven individuals (periodontal ligament pool group) and also from four teeth of one individual (periodontal ligament single group), after enzymatic digestion. The cells were cultured in specific inductive medium. Analyses of protein and gene expression were performed through immunocytochemistry and reverse transcription-polymerase chain reaction techniques, respectively. RESULTS: Mesodermal phenotypes (adipogeneic, osteogenic and myofibroblastic) were identified after culture in inductive medium. Immunocytochemistry analyses showed the presence of the nestin marker of neural stem cells and also markers of undifferentiated neural crest cells (HNK1, p75). When cultured in inductive medium that allowed neural differentiation, the cells showed markers for beta-tubulin III, neurofilament M, peripherin, microtubule-associated protein 2 and protein zero. The results were similar between the two study groups (the periodontal ligament pool group and the periodontal ligament single group). CONCLUSION: This research provides evidence that human periodontal ligament, in addition to its mesodermal derivatives, produces neural crest-like cells. Such features suggest a recapitulation of their embryonic state. The human periodontal ligament revealed itself as a viable alternative source for possible primitive precursors to be used in stem-cell therapies.
Assuntos
Células-Tronco Adultas , Crista Neural/citologia , Ligamento Periodontal/citologia , Adolescente , Adulto , Antígenos CD57/análise , Linhagem da Célula , Células Cultivadas , Perfilação da Expressão Gênica , Humanos , Imuno-Histoquímica , Proteínas de Filamentos Intermediários/análise , Glicoproteínas de Membrana/análise , Proteínas Associadas aos Microtúbulos/análise , Proteína P0 da Mielina/análise , Proteínas do Tecido Nervoso/análise , Nestina , Proteínas de Neurofilamentos/análise , Ligamento Periodontal/química , Periferinas , Tubulina (Proteína)/análise , Adulto JovemRESUMO
Hereditary motor and sensory neuropathy (HMSN) or Charcot-Marie-Tooth disease (CMT) is the most common hereditary illness of the peripheral nervous system. The genetics and the physiopathological aspects of the disease clarified until know, are here summarized. More than twenty genes and ten additional loci have been related with HMSN. These findings contribute to understand the metabolism of peripheral nerves and give the basis for molecular diagnostics and future therapy. Several Costa Rican families with CMT have been identified, specially with axonal forms. Two families present mutations in the myelin protein zero gene (IMPZ). In addition, linkage have been found between the disease and locus 19q13.3 in an extended family, and a mutation segregating with the disease is present in a candidate gene of the critical interval. Costa Rica has several advantages for genetical studies, that can contribute importantly in the generation of knowledge in the neurogenetical field.
Assuntos
Humanos , Doença de Charcot-Marie-Tooth/genética , Mutação/genética , Predisposição Genética para Doença/genética , Proteína P0 da Mielina/genética , Ligação Genética , Costa Rica , Marcadores Genéticos/genéticaRESUMO
Hereditary motor and sensory neuropathy (HMSN) or Charcot-Marie-Tooth disease (CMT) is the most common hereditary illness of the peripheral nervous system. The genetics and the physiopathological aspects of the disease clarified until know, are here summarized. More than twenty genes and ten additional loci have been related with HMSN. These findings contribute to understand the metabolism of peripheral nerves and give the basis for molecular diagnostics and future therapy. Several Costa Rican families with CMT have been identified, specially with axonal forms. Two families present mutations in the myelin protein zero gene (IMPZ). In addition, linkage have been found between the disease and locus 19q13.3 in an extended family, and a mutation segregating with the disease is present in a candidate gene of the critical interval. Costa Rica has several advantages for genetical studies, that can contribute importantly in the generation of knowledge in the neurogenetical field.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Predisposição Genética para Doença/genética , Mutação/genética , Proteína P0 da Mielina/genética , Costa Rica , Ligação Genética/genética , Marcadores Genéticos/genética , HumanosRESUMO
Mycobacterium leprae, the causative agent of leprosy invades Schwann cells of the peripheral nerves leading to nerve damage and disfigurement, which is the hallmark of the disease. Wet experiments have shown that M. leprae binds to a major peripheral nerve protein, the myelin P zero (P0). This protein is specific to peripheral nerve and may be important in the initial step of M. leprae binding and invasion of Schwann cells which is the feature of leprosy. Though the receptors on Schawann cells, cytokines, chemokines and antibodies to M. leprae have been identified the molecular mechanism of nerve damage and neurodegeneration is not clearly defined. Recently pathogen and host protein/nucleotide sequence similarities (molecular mimicry) have been implicated in neurodegenerative diseases. The approach of the present study is to utilise bioinformatic tools to understand leprosy nerve damage by carrying out sequence and structural similarity searches of myelin P0 with leproma and other genomic database. Since myelin P0 is unique to peripheral nerve, its sequence and structural similarities in other neuropathogens have also been noted. Comparison of myelin P0 with the M. leprae proteins revealed two characterised proteins, Ferrodoxin NADP reductase and a conserved membrane protein, which showed similarity to the query sequence. Comparison with the entire genomic database (www.ncbi.nlm.nih.gov) by basic local alignment search tool for proteins (BLASTP) and fold classification of structure-structure alignment of proteins (FSSP) searches revealed that myelin P0 had sequence/structural similarities to the poliovirus receptor, coxsackie-adenovirus receptor, anthrax protective antigen, diphtheria toxin, herpes simplex virus, HIV gag-1 peptide, and gp120 among others. These proteins are known to be associated directly or indirectly with neruodegeneration. Sequence and structural similarities to the immunoglobin regions of myelin P0 could have implications in host-pathogen interactions, as it has homophilic adhesive properties. Although these observed similarities are not highly significant in their percentage identity, they could be functionally important in molecular mimicry, receptor binding and cell signaling events involved in neurodegeneration.
Assuntos
Humanos , Biologia Computacional , Conformação Proteica , Dados de Sequência Molecular , Doenças Neurodegenerativas , Hanseníase , Ligação Proteica , Mimetismo Molecular , Modelos Moleculares , Mycobacterium leprae , Proteína P0 da Mielina , Proteínas de Bactérias , Proteínas de Membrana , Proteômica , Receptores Virais , Sequência de AminoácidosRESUMO
Charcot-Marie-Tooth disease type 1B (CMT 1B) is caused by mutations in the gene coding for peripheral myelin protein zero (MPZ, P0) that plays a fundamental role in adhesion and compaction of peripheral myelin. Here we report a Costa Rican family with a hereditary peripheral neuropathy due to a novel Tyr145Ser MPZ mutation. Four family members were heterozygously affected; two siblings of two heterozygous carriers were homozygous for this mutation. On neurological examination the heterozygous parents and their homozygous children both showed distal sensory deficits. The mother and the siblings displayed impaired deep tendon reflexes and mild sensory ataxia. The homozygous individuals were more severely affected with an earlier age of onset, distal motor weakness, and pupillary abnormalities. Electrophysiological studies revealed both signs of demyelination and axonal nerve degeneration. The sural nerve biopsy of one sibling showed thinly myelinated nerve fibers, onion bulb formation, and clusters of regenerating fibers. On electron microscopy axonal degeneration and decompaction of inner myelin layers were found. This Costa Rican family shows phenotypic variability depending on the homozygous or heterozygous state of the Tyr145Ser mutation carriers.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Proteína P0 da Mielina/genética , Mutação Puntual , Doença de Charcot-Marie-Tooth/patologia , Costa Rica , Análise Mutacional de DNA , Saúde da Família , Feminino , Heterozigoto , Homozigoto , Humanos , Masculino , Linhagem , Fenótipo , Nervo Sural/patologiaRESUMO
Schwann cells (SCs) in culture, without the presence of axons, become de-differentiated, reaching a condition similar to that of their precursor cells. The cytoplasmic accumulation of transferrin (Tf) in the myelinated peripheral nerve has been reported and data in the literature support a role for apoTf in myelination in the CNS. In the present report, we used SC cultures to evaluate the capacity of apoTf and holoTf to prevent cell de-differentiation promoted by fetal calf serum deprivation. SCs incubated in a serum-free medium showed a decrease in the expression of myelin basic protein (MBP) and P(0), markers of mature myelin-forming SCs, together with an increase in the levels of p75NTR and glial fibrillary acidic protein, markers of immature SCs. Treatment with holoTf prevented the decrease in expression of MBP and P(0) and the increase in p75NTR. ApoTf was unable to prevent these changes except when iron was added to the cultures. These results suggest a role for holoTf in the regulation of myelin formation by SCs.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Células de Schwann/efeitos dos fármacos , Transferrina/farmacologia , Animais , Animais Recém-Nascidos , Western Blotting , Diferenciação Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Meios de Cultura , Proteína Glial Fibrilar Ácida/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Imuno-Histoquímica , Ferro/farmacologia , Proteína Básica da Mielina/efeitos dos fármacos , Proteína Básica da Mielina/metabolismo , Proteína P0 da Mielina/efeitos dos fármacos , Proteína P0 da Mielina/metabolismo , Ratos , Receptor de Fator de Crescimento Neural , Receptores de Fator de Crescimento Neural/efeitos dos fármacos , Receptores de Fator de Crescimento Neural/metabolismo , Células de Schwann/citologia , Células de Schwann/metabolismo , Transferrina/metabolismoRESUMO
In this work we analyzed variations in the expression of MBPs and P0 in ligated sciatic nerves of young and adult rats at 3, 7, and 14 days postligation (PL), by immunohistochemistry and SDS-PAGE of isolated myelin. A protein redistribution was seen in the distal stump of ligated nerves with the appearance of immunoreactive clusters. Using the KS400 image analyzer, immunostained area values were obtained from the different nerves dissected. In adult rats, there was an increase of the immunostained area for MBP from 3 to 7 days PL, coincident with a reorganization of the marker in clusters, followed by a marked decrease at 14 days. P0 immunolabeling gave similar results without, however, a decrease of the immunostained area at the longer survival time tested. Young animals showed an acceleration in the process of protein redistribution and digestion within ligated nerves, which followed a similar pattern as that of adult animals. Analysis by electrophoresis showed a marked decrease in P0 and MBP at 7 days PL in young rats and 14 days PL in adult rats. The functional significance of protein clustering within myelin in injured nerves deserves further analysis.
Assuntos
Proteína Básica da Mielina/metabolismo , Proteína P0 da Mielina/metabolismo , Nervo Isquiático/metabolismo , Animais , Eletroforese em Gel de Poliacrilamida , Imuno-Histoquímica , Ratos , Ratos Wistar , Nervo Isquiático/lesõesRESUMO
Expression of myelin P0 protein by myelinating Schwann cells in vivo is dependent on axonal influences. This report describes P0 gene expression during development of rat sciatic nerve and spinal nerve roots using Northern blotting, in situ hybridization and immunohistochemistry. We demonstrate that: (1) the appearance of P0 mRNA and P0 protein in Schwann cells during nerve development in the rat begins prenatally, at day 18 post-fertilization (E18); (2) P0 mRNA and P0 protein have essentially identical developmental profiles, and are expressed in Schwann cells that are many days prior to myelin formation; (3) initial P0 gene expression is greatest in Schwann cells at the periphery of nerve bundles and in Schwann cells in contact with motor axons; (4) the decline in P0 expression with nerve maturation is accompanied by a sharp decline in P0 message levels in most Schwann cells, but a small subpopulation of these cells continue to synthesize very high levels of P0 mRNA. This study provides data on myelin P0 protein gene expression and distribution during PNS development and adds further insights into the axonal influences controlling Schwann cell behaviour during myelination of the rat PNS.
Assuntos
Envelhecimento/fisiologia , Desenvolvimento Embrionário e Fetal , Expressão Gênica , Proteínas da Mielina/biossíntese , Neurônios/metabolismo , RNA Mensageiro/biossíntese , Nervo Isquiático/metabolismo , Raízes Nervosas Espinhais/metabolismo , Animais , Northern Blotting , Moléculas de Adesão Celular Neuronais/biossíntese , Idade Gestacional , Hibridização In Situ , Proteína P0 da Mielina , Proteínas da Mielina/análise , Neurônios/citologia , Neurônios/fisiologia , RNA Mensageiro/análise , Ratos , Ratos Endogâmicos Lew , Nervo Isquiático/embriologia , Nervo Isquiático/crescimento & desenvolvimento , Raízes Nervosas Espinhais/embriologia , Raízes Nervosas Espinhais/crescimento & desenvolvimentoRESUMO
1. The myelin protein profiles in the CNS and PNS of three species of amphibians were analyzed by biochemical and immunohistochemical methods. 2. The CNS myelin of the African clawed frog (Xenopus) and the Mexican salamander (axolotl) contained, in addition to proteolipid protein, a unique protein zero (P0)-like protein, whereas the adult bullfrog did not. 3. A strong expression of the P0-like protein in the bullfrog CNS myelin was found transiently at ontogenetically early phases including at the time of metamorphosis. 4. The CNS P0-like protein and the PNS P0 protein showed a difference in reactivity with lectins and anti-L2/HNK-1 antibodies, suggesting that the two proteins differ in some aspects of their carbohydrate structures.