RESUMO
CCAAT enhancer binding proteinα (C/EBPα) is a transcription factor expressed only in certain tissues, including the liver. It has been previously demonstrated that C/EBPα may induce apoptosis in hepatic stellate cells (HSCs), raising the question of whether acetylation of C/EBPα is associated with HSCs, and the potential associated mechanism. A total of three histone deacetylase inhibitors (HDACIs), including trichostatin A (TSA), suberoylanilide hydroxamic acid and nicotinamide, were selected to determine whether acetylation affects C/EBPα expression. A Cell Counting Kit8 assay was used to determine the rate of proliferation inhibition following treatment with varying doses of the three HDACIs in HSCT6 and BRL3A cells. Western blot analysis was used to examine Caspase3, 8, 9, and 12 levels in HSCT6 cells treated with adenoviralC/EBPα and/or TSA. Following treatment with TSA, a combination of reverse transcriptionquantitative polymerase chain reaction and western blot analyses was used to determine the inherent C/EBPα mRNA and protein levels in HSCT6 cells at 0, 1, 2, 4, 8, 12, 24, 36 and 48 h. Nuclear and cytoplasmic proteins were extracted to examine C/EBPα distribution. Coimmunoprecipitation analysis was used to examine the lysine acetylation of C/EBPα. It was observed that TSA inhibited the proliferation of HSCT6 cells to a greater extent compared with BRL3A cells, following treatment with the three HDACIs. TSA induced apoptosis in HSCT6 cells and enhanced the expression of C/EBPα. Following treatment of HSCT6 cells with TSA, inherent C/EBPα expression increased in a timedependent manner, and its lysine acetylation simultaneously increased. Therefore, the results of the present study suggested that TSA may increase C/EBPα expression by increasing its lysine acetylation in HSCs.
Assuntos
Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Células Estreladas do Fígado/metabolismo , Ácidos Hidroxâmicos/farmacologia , Lisina/metabolismo , Acetilação/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Estreladas do Fígado/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Humanos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , RNA Mensageiro/metabolismo , RatosRESUMO
A diode-pumped Nd:YVO4 laser passively Q switched by a semiconductor absorber is demonstrated. The Q-switched operation of the laser has an average output power of 135 mW with a 1.6 W incident pump power. The minimum pulse width is measured to be about 8.3 ns with a repetition rate of 2 MHz. To our knowledge, this is the first demonstration of a solid-state laser passively Q-switched by such a composite semiconductor absorber.