Miki Nagai

Gifu University, Gihu, Gifu, Japan

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Publications (15)51.14 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: Recessive dystrophic epidermolysis bullosa (RDEB) is a congenital bullous disease resulting from defective anchoring fibrils at the dermal-epidermal junction and mutations in the type VII collagen gene. In this report, we describe two patients with severe generalized RDEB. Patient 1 was a 24-day-old male infant, and patient 2 was a 1-day-old female infant. Immunofluorescence microscopy demonstrated absence of type VII collagen labeling in a skin sample of patient 1, and reduced staining in patient 2. Electron microscopy revealed absence of anchoring fibrils below the lamina densa in patient 1, and reduced or rudimentary anchoring fibrils in patient 2. Mutation analyses of COL7A1 in these patients revealed heteroallelic recessive mutations which resulted in premature termination codons (PTC): 6573+1G>C in intron81 and 886del6ins14 in exon 7 in patient 1, and 6573+1G>C in intron81 and 4535insC in exon 44 in patient 2. Heteroallelic combinations of PTC mutation generally result in the severe generalized type. Patient 2 has developed a digital fusion at age 2, which is a typical manifestation of severe generalized RDEB. The RDEB subtype is considered to be determined based on comprehensive information, including analysis of alleles, protein expression, ultrastructure and clinical symptoms after growth. However, mutation analyses of COL7A1 can provide valuable information estimating a diagnosis in early infancy.
    No preview · Article · Jun 2011 · The Journal of Dermatology
  • [Show abstract] [Hide abstract] ABSTRACT: High-dose intravenous immunoglobulin (HD-IVIg) has several distinguishing therapeutic characteristics. However, a certain number of pemphigus cases have been experienced, which did not respond to HD-IVIg. This is the first case report that the serum level of anti-desmoglein (Dsg) 1 antibody rebounded, critically associated with IgG serum level. We describe a patient with pemphigus foliaceus (PF), unresponsive to oral prednisolone followed by pulse therapy and double-filtration plasmapheresis, in whom clinical remission was induced by 4 courses of HD-IVIg. Anti-Dsg1 antibody levels, serum IgG and disease activity were monitored. Anti-Dsg1 antibody titers rapidly decreased after IVIg treatment when total IgG levels were high; however, the serum level of anti-Dsg1 antibody rebounded as the total IgG level returned to normal. The levels of anti-Dsg1 antibody were decreased for an average of 13.7 days after treatment. The therapeutic effect of IVIg treatment was associated with an increased serum level of total IgG. IVIg therapy reduced the titers of autoantibody by accelerating the catabolism of immunoglobulin induced by high IgG serum levels. IVIg itself appears to accelerate IgG degradation rather than suppress IgG production. Sufficient suppression of antibody production is critical for successful treatment with IVIg.
    No preview · Article · Jan 2011 · European journal of dermatology: EJD
  • Y Aoyama · M Nagai · Y Kitajima
    [Show abstract] [Hide abstract] ABSTRACT: Pemphigus vulgaris (PV) is characterized by autoantibodies against desmoglein (Dsg) 3 or both Dsg1 and Dsg3, i.e. desmosomal adhesion molecules. We examined whether or not PV IgG binding to Dsg3 directly impairs the adhesion of desmosomes. For immunofluorescence microscopy, keratinocytes were first incubated with PV IgG for 30 min in low Ca(2+) medium, in which no desmosomes were formed, and then for 1 h in high Ca(2+) medium to generate desmosomes. For immunoelectron microscopy, after a 30-min incubation with PV IgG in low Ca(2+) medium, cells were incubated with antihuman IgG with 5-nm gold particles for 5 min; after washing, cells were further incubated in high Ca(2+) medium for 1 h. For tracing of PV IgG/Dsg3 immune complexes formed in the desmosomal core domain, cells were first incubated with PV IgG for 5 min to allow PV IgG to bind the desmosomal core domain and were further incubated with PV IgG-free medium for different times. Immunofluorescence microscopy revealed that PV IgG bound in a random-punctate pattern on the cell surface in low Ca(2+) medium was translocated to the cell-cell contacts forming a dotted-linear distribution, suggesting desmosome generation even in the presence of PV IgG. Immunoelectron microscopy revealed that half-desmosome-like structures decorated with gold particles in low Ca(2+) keratinocytes coupled to form desmosomes and gold particles were sandwiched in the desmosomal core domain after Ca(2+) switch, even though their surfaces were covered with PV IgG/antihuman IgG 5-nm gold particles. In the tracing experiments, although PV IgG demonstrated a dotted-linear distribution along the cell-cell contacts colocalized with desmoplakin (DPK) after a 30-min tracing, it disappeared from cell-cell contacts after a 5-h tracing, leaving DPK and desmocollin 3. These results suggest that the PV IgG/Dsg3 immune complexes are excluded from the desmosomal core domain rather than directly splitting the desmosome.
    No preview · Article · Mar 2010 · British Journal of Dermatology
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    [Show abstract] [Hide abstract] ABSTRACT: Recent studies have shown that skin injury recruits bone marrow-derived fibroblasts (BMDFs) to the site of injury to accelerate tissue repair. However, whether uninjured skin can recruit BMDFs to maintain skin homeostasis remains uncertain. Here, we investigated the appearance of BMDFs in normal mouse skin after embryonic bone marrow cell transplantation (E-BMT) with green fluorescent protein-transgenic bone marrow cells (GFP-BMCs) via the vitelline vein, which traverses the uterine wall and is connected to the fetal circulation. At 12 weeks of age, mice treated with E-BMT were observed to have successful engraftment of GFP-BMCs in hematopoietic tissues accompanied by induction of immune tolerance against GFP. We then investigated BMDFs in the skin of the same mice without prior injury and found that a significant number of BMDFs, which generate matrix proteins both in vitro and in vivo, were recruited and maintained after birth. Next, we performed E-BMT in a dystrophic epidermolysis bullosa mouse model (col7a1(-/-)) lacking type VII collagen in the cutaneous basement membrane zone. E-BMT significantly ameliorated the severity of the dystrophic epidermolysis bullosa phenotype in neonatal mice. Type VII collagen was deposited primarily in the follicular basement membrane zone in the vicinity of the BMDFs. Thus, gene therapy using E-BMT into the fetal circulation may offer a potential treatment option to ameliorate genetic skin diseases that are characterized by fibroblast dysfunction through the introduction of immune-tolerated BMDFs.
    Full-text · Article · Oct 2008 · American Journal Of Pathology
  • [Show abstract] [Hide abstract] ABSTRACT: A case of severe pemphigus vulgaris (PV), which did not respond to pulse therapy with intravenous (IV) methylprednisolone (1,000 mg/day for 3 days), but was successfully treated with a combination of double-filtration plasmapheresis (DFPP), immediately followed by high-dose IVIg (20 g/day for 5 days), eventually leading to suppression of the rebound increase in pathogenic PV-IgG for 12 months, is reported. Weekly enzyme-linked immunosorbent assay for desmoglein (Dsg) 1 and Dsg3 demonstrates a distinct difference in the alteration curves of serum levels of pathogenic IgG (anti-Dsg1 and Dsg3 antibodies) after DFPP with and without high-dose IVIg. Our experience suggests that combination therapy of DFPP with high-dose IVIg is effective for pathogenic PV-IgG removal and prevention of feedback rebound increases in pathogenic PV-IgG, leading to a long-term amelioration of clinical blistering in the present case.
    No preview · Article · Sep 2008 · European journal of dermatology: EJD
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    [Show abstract] [Hide abstract] ABSTRACT: P120-catenin (p120ctn) is an armadillo-repeat protein that directly binds to the intracytoplasmic domains of classical cadherins. p120ctn binding promotes the stabilization of cadherin complexes on the plasma membrane and thus positively regulates the adhesive activity of cadherins. Using co-immunoprecipitation, we show here that p120ctn associates to desmogleins (Dsg) 1 and 3. To determine which region is involved in the association between Dsg3 and p120ctn, we constructed mutant Dsg3 proteins, in which various cytoplasmic subdomains were removed. The tailless Dsg3 constructs Delta IA:AA1-641Dsg3 and Delta 641-714Dsg3, which do not contain the intracellular anchor (IA) region, did not coprecipitate with p120cn, nor did they colocalize at the plasma membrane. Immunocytochemical analysis revealed that p120ctn does not localize to desmosomes, but colocalizes with Dsg3 at the cell surface. A biotinylation assay for Dsg3 showed that biotinylated Delta 641-714Dsg3 was turned over more rapidly than wild-type Dsg3. These results indicate that the membrane proximal region (corresponding to residues 641-714) in the IA region of Dsg3 is necessary for complex formation with p120ctn, and to maintain free Dsg3 at the cell surface before it is integrated into desmosomes. In summary, we show that p120ctn is a novel interactor of the Dsg proteins, and may play a role in desmosome remodeling.
    Full-text · Article · Jun 2008 · Experimental Cell Research
  • Y. Isa · Y. Aoyama · M. Nagai · K. Tsunoda · M. Amagai · Y. Kitajima
    No preview · Conference Paper · Apr 2008
  • M. Kanno · Y. Aoyama · M. Nagai · Y. Yamamoto · Y. Kitajima
    No preview · Conference Paper · Aug 2006
  • No preview · Conference Paper · Apr 2006
  • No preview · Article · Jan 2005
  • No preview · Article · Jan 2005
  • [Show abstract] [Hide abstract] ABSTRACT: A 16-year-old girl case of contact dermatitis due to using a commercially gummed sticker inside of the socks around bilateral lower limbs was reported. She visited our department of hospital on May 7th, 2002, because of complaining erythema with pigmentation and purpura around lower limbs accompanying with serous papules on the upper limbs and trunk for one week. She has no specific family history and no past history. Histopathological examination biopsied from the lower limb revealed mononuclear cell infiltration around the blood vessels in the upper dermis with exocytosis in the irregularly elongated epidermis. Patch test using the sticker showed positive reactions, whereas more detail patch test examination using each material was not able to be carried out. It is thought that scattered serous papules seen on the upper limbs and trunk occurred as id reaction or autosensitization. Blood examination revealed no abnormality except for leucocytosis (10,300/mm3), polycytemia (528 × 104/mm3), and hyperimmunoglobulin E (950 IU/ml). This sticker made by Hakugen Co, Ltd (Tokyo, Japan) was consisted of complex jellymer of polyacryl sodium chloride/triethanolamine (CH 2·CH·COONa)n, (CH2·CH· COON(C2H4OH)3)n (5-15%) and ethylalcohol (10-30%), glycerin (less than 15%) and flavor with small amount of water.
    No preview · Article · Jan 2005 · Nishi Nihon Hifuka
  • [Show abstract] [Hide abstract] ABSTRACT: Epidermolysis bullosa simplex (EBS) is an autosomal-dominant inherited blistering skin disease characterized by intraepidermal blistering due to mechanical stress-induced degeneration of basal keratinocytes. EBS is caused by mutations in either keratin 5 or keratin 14, the major keratins expressed in the basal layer of the epidermis. We experienced a unique EBS-affected family. The proband had a heterozygous 1649delG mutation in the keratin 5 gene and had been reported as a case of de novo mutation, because the mutations were not detected in the parents' DNA from blood samples. However, the proband's younger sister was revealed to have the same disease at birth and we found the same mutation in her. We reinvestigated the familial segregation of the 1649delG mutation and it was shown that the mother's DNA from hair bulb and buccal cell samples had the 1649delG mutation heterozygously, but her DNA from blood samples did not. A careful check on the mother's history disclosed that she had migratory circinate pigmentation in her skin in childhood, which means maternal somatic and germline mosaicism. The demonstration of somatic and gonadal mosaicism in the keratin 5 gene is important for accurate genetic counselling of families with sporadic cases of EBS.
    No preview · Article · Oct 2004 · Clinical Genetics
  • No preview · Article · Jan 2004
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    [Show abstract] [Hide abstract] ABSTRACT: We report here two unrelated families in Japan and Korea having patients with a unique type of epidermolysis bullosa simplex and a novel mutation in the keratin gene KRT5, i.e., a frameshift and delayed stop codon inconsistent with any subtype described before. The patients showed migratory circinate erythema and multiple vesicles on the circular belt-like areas affected by erythema. Electron microscopy of skin biopsies showed a reduction in the number of keratin intermediate filaments in the basal cells without tonofilament clumping. We identified a novel heterozygous deletion mutation (1649delG of KRT5) in both cases. This deletion is predicted to produce a mutant keratin 5 protein with a frameshift of its terminal 41 amino acids and 35 amino acids longer than the wild-type keratin 5 protein due to a delayed termination codon. As the same abnormal elongated mutant KRT5 gene was found in the independent families, the predicted abnormal elongated keratin protein is likely to lead to an atypical clinical phenotype that has never been reported, possibly by interfering with the functional interaction between keratin and its associated proteins.
    Full-text · Article · Oct 2003 · Journal of Investigative Dermatology