ABSTRACT
SUMMARY: The skin, located on the outermost part of the body, is always exposed to external stimuli such as sunlight. The exposure of skin to ultraviolet B (UVB) radiation from sunlight is known to be a major environmental factor in inducing photoaging. After exposure to UVB, an increase in reactive oxygen species can affect the expression and activity of many critical proteins depending on the duration and dose of the UVB radiation. Mammalian sirtuins (SIRTs), which are nicotinamide dinucleotide-dependent protein deacetylases, are well known for playing a role in cellular longevity. However, little is known about SIRT protein alterations in keratinocytes upon UVB irradiation according to SIRT subtypes. Therefore, in this study, the distribution of non-mitochondrial SIRT1, SIRT2, and SIRT6 proteins was investigated by immunofluorescence (IF) staining of the skin of SKH-1 mice (n=12) after UVB irradiation for 10 weeks. After UVB irradiation for 10 weeks, the IF of both SIRT1 and SIRT6 was significantly increased in the UVB-irradiated mice group (UG), but the difference in SIRT2 IF was not statistically significant between the control group (CG) and the UG. The translocation of both SIRT1 and SIRT6 IF from the nucleus to the cytoplasm of keratinocytes was observed in the upper epidermis of the UG, whereas SIRT2 IF was localized in the cytoplasm of keratinocytes in the epidermis in both the CG and the UG. The translocation of SIRT1 and SIRT6 IF from the nucleus to the cytoplasm of keratinocytes may account for the physiologically protective action of keratinocytes against UVB irradiation. However, the exact role of SIRT1 and SIRT6 translocation in keratinocytes, where SIRT1 and SIRT6 shuttle from the nucleus to the cytoplasm, is not well known. Therefore, further studies are needed to understand the molecular mechanisms of SIRT1 and SIRT6 translocation in keratinocytes upon UVB irradiation.
La piel, situada en la parte más externa del cuerpo, está siempre expuesta a estímulos externos como la luz solar. Se sabe que la exposición de la piel a la radiación ultravioleta B (UVB) de la luz solar es un factor ambiental importante en la inducción del fotoenvejecimiento. Después de la exposición a los rayos UVB, un aumento en las especies reactivas de oxígeno puede afectar la expresión y la actividad de muchas proteínas críticas según la duración y la dosis de la radiación UVB. Las sirtuinas de mamíferos (SIRT), que son proteínas desacetilasas dependientes de dinucleótidos de nicotinamida, son bien conocidas por desempeñar un papel en la longevidad celular. Sin embargo, se sabe poco sobre las alteraciones de la proteína SIRT en los queratinocitos tras la irradiación UVB según los subtipos de SIRT. Por lo tanto, en este estudio, se investigó la distribución de las proteínas SIRT1, SIRT2 y SIRT6 no mitocondriales mediante tinción de inmunofluorescencia (IF) de la piel de ratones SKH-1 (n = 12), después de la irradiación con UVB durante 10 semanas. Posterior a la irradiación, el IF de SIRT1 y SIRT6 aumentaron significativamente en el grupo de ratones irradiados con UVB (UG), pero la diferencia en SIRT2 IF no fue estadísticamente significativa entre el grupo control (CG) y el UG. La translocación de SIRT1 y SIRT6 IF desde el núcleo al citoplasma de los queratinocitos se observó en la epidermis superior de la UG, mientras que SIRT2 IF se localizó en el citoplasma de los queratinocitos en la epidermis, tanto en el GC, como en la UG. La translocación de SIRT1 y SIRT6 IF del núcleo al citoplasma de los queratinocitos puede explicar la acción protectora fisiológica de estos contra la radiación UVB. Sin embargo, el papel exacto de la translocación de SIRT1 y SIRT6 en los queratinocitos, donde SIRT1 y SIRT6 se trasladan desde el núcleo al citoplasma, no se conoce bien. Por lo tanto, se necesitan más estudios para comprender los mecanismos moleculares de la translocación SIRT1 y SIRT6 en los queratinocitos tras la irradiación UVB.
Subject(s)
Animals , Male , Mice , Ultraviolet Rays , Keratinocytes/radiation effects , Sirtuins/radiation effects , Time Factors , Skin Aging , Fluorescent Antibody Technique , Sirtuins/analysisABSTRACT
Com o aumento da expectativa de vida, o estudo do processo de envelhecimento orgânico tem sido estimulado. O envelhecimento da pele, órgão que espelha os sinais do tempo, é processo de deterioração progressiva, tempo-dependente, e pode ser intensificado pela exposição solar, então designado fotoenvelhecimento. O dano das radiações sobre diversas estruturas celulares e cutâneas leva a alterações morfológicas nesses componentes, fruto de modificações biomoleculares. Muitas pesquisas são desenvolvidas com o intuito de combater ou minimizar os efeitos do fotoenvelhecimento, porém a principal estratégia nesse sentido continua sendo a prevenção, só conseguida pelo progressivo desvendar dos mecanismos fisiopatogênicos envolvidos nesse processo.
As a result of the increase in life expectancy, the study of the organic process of aging has been stimulated. Skin ageing, which reflects the signs of time, is a time-dependent process of progressive deterioration that can be intensified by sun exposure, which is known as photoaging. The damage of radiation on various cell structures and on the skin results in molecular and morphological changes to these components. Many research studies are performed to try to minimize the effects of photoaging; however, the main strategy to manage it is still prevention, which will only be achieved once we learn about the mechanisms involved in the process.