Activation of vascular endothelial growth factor receptor 2 in a cellular model of loricrin keratoderma.
Loricrin is a major constituent of the epidermal cornified cell envelope. Recently, heterozygous loricrin gene mutations have been identified in two dominantly inherited skin diseases, Vohwinkel syndrome with ichthyosis and progressive symmetric erythrokeratoderma, collectively termed loricrin keratoderma. We generated stable HaCaT cell lines that express wild-type (WT) loricrin and a mutant form found in Vohwinkel syndrome with ichthyosis, using an ecdysone-inducible promoter system. The cells expressing the mutant loricrin grew more rapidly than those expressing WT loricrin after induction for 5 days. Confocal immunofluorescence microscopy revealed that phospho-Akt occurred in the nucleolus where the mutant loricrin was also located. The level of activity of Akt kinase was about nine times higher in cells with the mutant than in those with WT loricrin. ERK1/2, the epidermal growth factor receptor, vascular endothelial growth factor (VEGF) receptor 2 and Stat3 were all phosphorylated in cells with the mutant loricrin. The docking proteins, Gab1 and c-Cbl, were also tyrosine-phosphorylated in these cells. Furthermore, chromatin immunoprecipitation assays showed that Stat3 protein bound to the VEGF promoter in cells with the mutant. Thus, this study suggests that VEGF release and the subsequent activation of VEGF receptor 2 link loricrin gene mutations to rapid cell proliferation in a cellular model of loricrin keratoderma.
Department of Dermatology, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan. kyoneda@med.kagawa-u.ac.jp
Kozo
K
Yoneda
Toshio
T
Demitsu
Kozo
K
Nakai
Tetsuya
T
Moriue
Wataru
W
Ogawa
Junsuke
J
Igarashi
Hiroaki
H
Kosaka
Yasuo
Y
Kubota
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D010766:Phosphorylation / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D012873:Skin Diseases, Genetic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C098587:GAB1 protein, human; D008565:Membrane Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C064554:loricrin; D050721:Proto-Oncogene Proteins c-cbl; D040301:Vascular Endothelial Growth Factor Receptor-2; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3; C067419:CBL protein, human