RESUMO
The pink-eyed dilution protein (P-protein) plays a critical role in melanin synthesis in melanocytes and retinal pigment epithelium cells. Mutation in this protein may cause complete or partial albinism. Role of the P-protein ranges in melanin synthesis to maturation and trafficking of the melanosomes. The aim of the present study was to evaluate the effect of P-protein inhibition on melanosome biology by comparing the shape, size, count, and types of melanosomes in melan-a melanocytes. The cells were extensively examined by the transmission electron microscopy. The P-protein inhibition was carried by P-protein-siRNA transfection to melan-a melanocytes, B16F10 mouse melanoma, and melan-p1 cells. Measurement of melanin contents, cellular tyrosinase, and different tyrosinase related proteins were also determined to investigate the effect of P-protein siRNA transfection on melanocytes. Results suggested that the inhibition of P-protein can significantly change the melanosomal morphology, types and their respective numbers, and provided a novel strategy for the control of melanin synthesis.
Assuntos
Proteínas de Transporte/metabolismo , Regulação para Baixo , Melanossomas/metabolismo , Melanossomas/ultraestrutura , Proteínas de Membrana/metabolismo , RNA Interferente Pequeno/metabolismo , Animais , Regulação para Baixo/efeitos dos fármacos , Células HeLa , Humanos , Melaninas/biossíntese , Melanossomas/efeitos dos fármacos , Camundongos , Monofenol Mono-Oxigenase/metabolismo , Transfecção , Tirosina/farmacologiaRESUMO
In vitiligo, the active melanocytes in the epidermis are totally missing, whereas melanoblast cells in the outer root sheath of hair follicles are not affected. In an attempt to find potent repigmenting agents for vitiligo therapy, pod extracts of Cassia occidentalis was found to be effective in inducing differentiation and migration of mouse melanoblast cell line. Methanolic extract redissolved in DMSO at 12.5 µg/ml was found to cause 3.5- to 3.8-fold melanin induction in melb-a melanoblast cells after 4 days in treatment medium. In addition it induced the tyrosinase activity and altered melb-a cell morphology. Transwell migration assay showed the potential of this herbal candidate to induce direct migration of treated cells. To the best of our knowledge, this is the first report investigating the effect of Cassia occidentalis on the differentiation and migration of melanoblast cells. The findings of present study are significant in designing preclinical and clinical studies on the efficacy of C. occidentalis as a stimulant for skin repigmentation in vitiligo.
