Pemphigus vulgaris-IgG causes a rapid depletion of desmoglein 3 (Dsg3) from the Triton X-100 soluble pools, leading to the formation of Dsg3-depleted desmosomes in a human squamous carcinoma cell line, DJM-1 cells.
In this study, we examined desmoglein (Dsg) 3 and other desmosomal molecules after pemphigus vulgaris (PV)-immunoglobulin G (IgG) binding to the Dsg3 on the cell surface in DJM-1 cells, a human squamous cell carcinoma cell line. After cells were incubated with PV-IgG for various time periods (0, 5, 10, 20, 30, 60 min, or 30 h), cells were fractionated into phosphate-buffered saline soluble (cytosol), phosphate-buffered saline insoluble-Triton X-100 soluble (membrane), and Triton X-100 insoluble (cytoskeleton) fractions, and subjected to immunoblotting and immunofluorescence microscopy using antibodies against Dsgl, Dsg3, plakoglobin, desmoplakin 1, and cytokeratins. Immunoblot analysis with PV-IgG revealed that Dsg3 was already dramatically depleted from the membrane fraction 20 min after PV-IgG treatment, whereas no reduction of Dsg3 was detected in the cytoskeleton fraction as examined by immunoblotting. A 30 h incubation with PV-IgG, however, caused a marked disappearance of Dsg3, but not other desmosomal molecules, from cytoskeleton fractions. Furthermore, double-staining immunofluorescence microscopy revealed that Dsg3 was depleted from the desmosomes whereas Dsg1, desmoplakin 1, plakoglobin, and keratin filaments were bound to desmosomes. These results provide a novel interpretation for a better understanding of mechanisms for blistering in PV; i.e., a possibility that PV-IgG generates the formation of aberrant desmosomes, which are lacking in Dsg3, but not other desmosomal constituents.
Aoyama
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Y
Department of Dermatology, Gifu University School of Medicine, Gifu City, Japan.
Kitajima
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Y
D001324:Autoantigens / Q000032:analysis*; D015820:Cadherins / Q000032:analysis* / Q000276:immunology; D002294:Carcinoma, Squamous Cell / Q000276:immunology; D003599:Cytoskeleton / Q000737:chemistry; D051184:Desmoglein 3; D003896:Desmosomes / Q000276:immunology*; D004817:Epidermis / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000276:immunology*; D008856:Microscopy, Fluorescence; D017830:Octoxynol / Q000494:pharmacology*; D010392:Pemphigus / Q000276:immunology*; D014407:Tumor Cells, Cultured
D001324:Autoantigens; D015820:Cadherins; C071894:DSG3 protein, human; D051184:Desmoglein 3; D007074:Immunoglobulin G; D017830:Octoxynol