OBJECTIVEPelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive leukoencephalopathy. Few reports of PMD patients without genetic confirmation have been published in the mainland of China. The clinical and genetic features of a family with PMD were analyzed, which may contribute to definite diagnosis, genetic counseling and prenatal diagnosis of this rare hereditary disease in China.

METHODSClinical data of the proband and other family members as well as 14 DNA samples were collected. Clinical features including symptoms, signs and cranial MRI were analyzed. Multiplex ligation-dependent probe amplification (MLPA) assays were performed to detect PLP1 duplication, which helps identify the type of PLP1 mutation in this family and the genotype-phenotype correlations.

RESULTS(1) The proband and the other 3 male patients in the family presented with nystagmus, motor retardation followed by regression. The cranial MRI of proband showed evidence of poor myelination with diffused high signal in white matter region on T2-weighed image and reduced amount of white matter in volume, which is consistent with the typical features of cranial MRI in PMD. (2) PLP1duplication was identified in the proband. Combined with the clinical features of the proband and other patients in this family, the diagnosis of classic form of PMD was confirmed. Another 3 females with normal phenotype in the family were proved to be carriers of PLP1duplication.

CONCLUSIONS(1) The Classic form of PMD in this pedigree is resulted from the PLP1 duplication, which is consistent with the previously reported genotype-phenotype correlations; (2) The results serve as an evidence for reliable genetic counseling and prenatal diagnosis for this family. (3) MLPA, which is a newly developed method, is a rapid and reliable technique to detect the whole gene duplication of PLP1.

Adult ; DNA Probes ; Genes ; Genetic Association Studies ; Humans ; Infant ; Male ; Mutation ; Myelin Proteolipid Protein ; genetics ; Pedigree ; Pelizaeus-Merzbacher Disease ; genetics ; Phenotype

BACKGROUNDPelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder with symptoms including nystagmus, impaired motor development, ataxia, and progressive spasticity. The proteolipid protein 1 (PLP1) gene is the only pathogenic gene of PMD. Duplication of the PLP1 gene is the most frequent gene defect, accounting for 50%-70% of PMD cases, whereas point mutations in the coding sequence or the splice sites account for 10%-25% of PMD cases. This study aimed to identify PLP1 mutations in nine unrelated Chinese patients (P1-9) with PMD, and 14 subjects from the family of patient 2 were also described.

METHODSGenomic DNA was extracted from peripheral blood samples. Gene dosage was determined using the multiplex ligation-dependent probe amplification (MLPA). All 7 exons and exon-intron boundaries of the PLP1 gene were amplified and analyzed using direct DNA sequencing.

RESULTSOf these nine patients, there were four transitional, four classical, and one connatal PMD according to their clinical and radiological presentations. PLP1 duplications were identified in patients 1-7 with PMD. Their mothers were PLP1 duplications carriers as well. Both duplication carriers and normal genotypes of PLP1 were identified in the family members of patient 2. A c.517C > T (p. P173S) hemizygous missense mutation in exon 4 was found in patient 8 with PMD, and his mother was shown to be a heterozygote of this mutation.

CONCLUSIONSWe identified seven genomic duplications and one missense mutation (p. P173S) of the PLP1 gene in eight Chinese patients with PMD. This is the report about PLP1 mutations in PMD patients from the mainland of China.

Child, Preschool ; Female ; Gene Duplication ; Humans ; Infant ; Male ; Mutation ; Myelin Proteolipid Protein ; genetics ; Nucleic Acid Amplification Techniques ; Pelizaeus-Merzbacher Disease ; genetics ; Sequence Analysis, DNA

It is well known that chronic ethanol treatment affects the synthesis of RNA and protein in the brain and the maintenance and function of nervous system. The changes in myelination-related genes are most prominent in human alcoholics. Previously, our cDNA microarray study showed altered Proteolipid protein (PLP), a major protein of central myelin. The present study aimed to gain more understanding of the expression of PLP after chronic ethanol treatment. Male Sprague-Dawley rats were daily treated with ethanol (15% in saline, 3 g/kg, i.p.) or saline for 14 days. Messenger RNAs from hippocampus of each group were subjected to cDNA expression array hybridization to determine the differential gene expressions. Among many ethanol responsive genes, PLP was negatively regulated by ethanol treatment, which is one of the most abundant proteins in the CNS and has an important role in the stabilization of myelin sheath. Using northern blot and immunohistochemical analysis, we showed the change in expression level of PLP mRNA and protein after ethanol treatment. PLP mRNA and protein were decreased in hippocampus of rat with chronic ethanol exposure, suggesting that ethanol may affect the stabilization of myelin sheath through the modulation of PLP expression and induce the pathophysiology of alcoholic brain.
Alcoholics ; Animals ; Blotting, Northern ; Brain ; Chimera ; DNA, Complementary ; Ethanol ; Gene Expression ; Hippocampus ; Humans ; Male ; Myelin Proteolipid Protein ; Myelin Sheath ; Nervous System ; Oligonucleotide Array Sequence Analysis ; Proteins ; Rats ; Rats, Sprague-Dawley ; RNA ; RNA, Messenger

Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder with a prototype of a dysmyelinating leukodystrophy that is caused by a mutation in the proteolipid protein 1 (PLP1) gene on the long arm of the X chromosome in band Xq22. This mutation results in abnormal expression or production of PLP. We here present a Korean boy with spastic quadriplegia, horizontal nystagmus, saccadic gaze, intentional tremor, head titubation, ataxia, and developmental delay. The brain magnetic resonance imaging (MRI) showed abnormally high signal intensities in the white matter tract, including a subcortical U fiber on the T2-weighted and fluid attenuated inversion recovery (FLAIR) image. The chromosomal analysis was normal; however, duplication of the PLP1 gene in chromosome Xq22 was detected when the multiplex ligation-dependent probe amplification (MLPA) method was used. We also investigated the pedigree for a genetic study related to PMD. This case suggests that the duplication mutation of the PLP1 gene in patients with PMD results in a mild clinical form of the disorder that mimics the spastic quadriplegia of cerebral palsy.
Brain/*pathology ; Child, Preschool ; Chromosome Mapping ; Chromosomes, Human, X ; Developmental Disabilities/diagnosis/genetics ; Exons ; Gene Duplication ; Humans ; Korea ; Magnetic Resonance Imaging/methods ; Mutation ; Myelin Proteolipid Protein/genetics ; Myelin Sheath/chemistry ; Pelizaeus-Merzbacher Disease/*diagnosis/*genetics ; Polymerase Chain Reaction/*methods

OBJECTIVETo investigate the effects of combination therapy with methylprednisolone (MP) and brain-derived neurotrophic factor (BDNF) on axonal remyelination and functional recovery after spinal cord injury in rats.

METHODSForty-five rats were randomly divided into three groups: Group A received MP and BDNF; group B received MP and cerebrospinal fluid (CSF); and group C received CSF only. Contusion injury to adult rat spinal cord was produced at the T(10) vertebra level followed by immediate intravenous MP or CSF, and was thereafter infused intrathecally with BDNF or CSF for 6 weeks. Axonal remyelination and functional recovery was observed using RT-PCR, immunohistochemistry and open field locomotion.

RESULTSAn increase of 28.4% +/- 2.3% in the expression of proteolipid protein (PLP) gene, an endogenous indicator of axonal remyelination, was demonstrated in group A 24 hours after injury. Ten weeks later, there were significant decreases in hematogenous inflammatory cellular infiltration in groups A and B compared to C (P < 0.05). Concomitantly, a significant amount of axonal remyelination was observed in group A compared to groups B and C (P < 0.05). Furthermore, combination therapy using MP and BDNF in group A resulted in stimulation of hindlimb activity as well as improvement in the rate of functional recovery in open field locomotion (P < 0.05).

CONCLUSIONSCombined therapy of MP and BDNF can improve functional recovery through mechanisms that include attenuating inflammatory cellular infiltration and enhancing axonal remyelination at the injury site. Such a combination may be an effective approach for treatment of spinal cord injury.

Animals ; Axons ; physiology ; Brain-Derived Neurotrophic Factor ; administration & dosage ; Drug Therapy, Combination ; Female ; Methylprednisolone ; administration & dosage ; Myelin Proteolipid Protein ; genetics ; Nerve Regeneration ; drug effects ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Recovery of Function ; Spinal Cord Injuries ; drug therapy ; metabolism ; physiopathology

Oligodendrocytes (OLs) are myelinating glial cells that form myelin sheaths around axons to ensure rapid and focal conduction of action potentials. Here, we found that an axonal outgrowth regulatory molecule, AATYK (apoptosis-associated tyrosine kinase), was up-regulated with OL differentiation and remyelination. We therefore studied its role in OL differentiation. The results showed that AATYK knockdown inhibited OL differentiation and the expression of myelin genes in vitro. Moreover, AATYK-deficiency maintained the proliferation status of OLs but did not affect their survival. Thus, AATYK is essential for the differentiation of OLs.
Animals ; Animals, Newborn ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Cell Differentiation ; drug effects ; physiology ; Cell Proliferation ; drug effects ; genetics ; Cells, Cultured ; Cuprizone ; toxicity ; Demyelinating Diseases ; chemically induced ; metabolism ; pathology ; Embryo, Mammalian ; Gene Expression Regulation, Developmental ; genetics ; Ki-67 Antigen ; metabolism ; Mice ; Mice, Inbred C57BL ; Myelin Basic Protein ; metabolism ; Myelin Proteolipid Protein ; metabolism ; Myelin Sheath ; drug effects ; metabolism ; Oligodendroglia ; drug effects ; metabolism ; Protein-Tyrosine Kinases ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo detect the function of proteolipid protein (PLP) peptide (residues 56 - 70)-specific CD(4)(+) T cells in experimental allergic encephalomyelitis (EAE) in Biozzi AB/H mice (H-2A(g7)).

METHODSBiozzi AB/H mice were immunized by synthetic PLP(56 - 70) peptide (DYEYLINVIHAFQYV) which was emulsified by sonication with complete Freund's adjuvant, a EAE model proven histologically and clinically. Murine splenocytes and spinal cord infiltrated (SCI) T cells were stimulated by PLP(56 - 70), then the CD(4)(+) T cells were isolated by Dynabeads, and confirmed by staining with anti-CD(4) antibody. Finally, the IL2 bioassay and IFN-gamma/IL4 ELISA were done to detect T cell proliferation and cytokine secretion after PLP(56 - 70) stimulation.

RESULTSThe histology of murine spinal cord showed a great number of lymphocytes infiltrated the spinal cord; the clinical signs showed high scores (4.3) on the peak, as well as a good EAE model. After being isolated by Dynabeads, CD(4)(+) T cells showed high purification (> 99%) by staining with anti-CD(4) antibody. IL2 bioassay showed that those T cells were PLP(56 - 70)-specific T cells. ELISA showed that those T cells had high IFN-gamma/IL4 ratio, indicating that they are T helper 1 (Th1) cells.

CONCLUSIONSPLP(56 - 70)-specific splenocytes and SCI CD(4)(+) T cells in EAE from Biozzi AB/H mice were detected and showed that both of them were PLP(56 - 70)-specific Th1 cells. It is beneficial to understand what kind of role these T cells play in the development of EAE.

Amino Acid Sequence ; Animals ; CD4-Positive T-Lymphocytes ; drug effects ; immunology ; metabolism ; Cell Line ; Encephalomyelitis, Autoimmune, Experimental ; immunology ; pathology ; Interferon-gamma ; metabolism ; Interleukin-2 ; metabolism ; Interleukin-4 ; metabolism ; Mice ; Mice, Inbred Strains ; Molecular Sequence Data ; Myelin Proteolipid Protein ; chemistry ; immunology ; Peptide Fragments ; administration & dosage ; immunology ; Spleen ; cytology ; immunology ; metabolism ; Th1 Cells ; drug effects ; immunology ; metabolism