RESUMO
Purpose: Complete deficiency of microphthalmia transcription factor (MITF) in Mitfmi-vga9/mi-vga9 mice is associated with microphthalmia, retinal dysplasia, and albinism. We investigated the ability of dopachrome tautomerase (DCT) promoter-mediated inducible ectopic expression of Mitf-M to rescue these phenotypic abnormalities. Methods: A new mouse line was created with doxycycline-inducible ectopic Mitf-M expression on an Mitf-deficient Mitfmi-vga9 background (DMV mouse). Adult DMV mice were phenotypically characterized and tissues were collected for histology, immunohistochemistry, and evaluation of Mitf, pigmentary genes, and retinal pigment epithelium (RPE) gene expression. Results: Ectopic Mitf-M expression was specifically induced in the eyes, but was not detected in the skin of DMV mice. Inducible expression of Mitf-M partially rescued the microphthalmia, RPE structure, and pigmentation as well as a subset of the choroidal and iris melanocytes but not cutaneous melanocytes. RPE function and vision were not restored in the DMV mice. Conclusions: Ectopic expression of Mitf-M during development of Mitf-deficient mice is capable of partially rescuing ocular and retinal structures and uveal melanocytes. These findings provide novel information about the roles of Mitf isoforms in the development of mouse eyes.
Assuntos
Expressão Ectópica do Gene/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Fator de Transcrição Associado à Microftalmia/genética , Epitélio Pigmentado da Retina/metabolismo , Animais , Western Blotting , Corioide/citologia , Desenvolvimento Embrionário , Feminino , Perfilação da Expressão Gênica , Técnicas de Genotipagem , Imuno-Histoquímica , Oxirredutases Intramoleculares/farmacologia , Iris/citologia , Masculino , Melanócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microftalmia/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Pele/citologiaRESUMO
Transient receptor potential vanilloid 1 (TRPV1) has emerged as a promising therapeutic target. While radiolabeled resiniferatoxin (RTX) has provided a powerful tool for characterization of vanilloid binding to TRPV1, TRPV1 shows 20-fold weaker binding to the human TRPV1 than to the rodent TRPV1. We now describe a tritium radiolabeled synthetic vanilloid antagonist, 1-((2-(4-(methyl-[3H])piperidin-1-yl-4-[3H])-6-(trifluoromethyl)pyridin-3-yl)methyl)-3-(3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-8-yl)urea ([3H]MPOU), that embodies improved absolute affinity for human TRPV1 and improved synthetic accessibility.
