RESUMO
Neurogenin3 (Ngn3) is a basic helix-loop-helix transcription factor that specifies pancreatic endocrine cell fates during pancreas development. It can also initiate a transdifferentiation program when expressed in pancreatic exocrine and ductal cells. However, how Ngn3 initiates a transcriptional cascade to achieve endocrine differentiation is still poorly understood. Here, we show that cell cycle and apoptosis regulator 1 (CCAR1), which is a transcriptional coactivator for nuclear receptors, also interacts with Ngn3. The association between Ngn3 and CCAR1 was verified by pull-down assays and co-immunoprecipitation analyses. Using gene reporter assays, we found that CCAR1 is essential for Ngn3 to activate the expression of the reporter genes containing the NeuroD promoter. Moreover, down-regulation of endogenous CCAR1 in the PANC-1 pancreatic ductal cell line inhibits the transdifferentiation program initiated by Ngn3. CCAR1 is, therefore, a novel partner of Ngn3 in mediating endocrine differentiation.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , Ilhotas Pancreáticas/citologia , Proteínas do Tecido Nervoso/metabolismo , Proteínas Reguladoras de Apoptose/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Ciclo Celular/genética , Diferenciação Celular/genética , Linhagem Celular , Regulação da Expressão Gênica , Células HeLa , Humanos , Proteínas do Tecido Nervoso/genética , Técnicas do Sistema de Duplo-HíbridoRESUMO
Indenopyridine hydrochloride (IH), an antispermatogenic agent, was tested to determine the testicular pathological changes, seminal spermatozoa concentrations and seminal plasma alkaline phosphatase levels in male dogs. A single oral dosage of 30 mg IH/kg BW induced the dissociation and premature release of germ cells into the lumens of seminiferous tubules. Ring-shaped spermatid nuclei, nuclear pykonosis of spermatocytes and multinucleated cell associations were also observed. Thereafter, the spermatogenic index (SI) significantly decreased one day after IH administration. Moreover, seminal spermatozoa concentrations decreased two weeks after drug treatment; and there was a statistically significant difference in spermatozoa production inhibited by IH compared to the control. Reversible spermatogenesis was noted 7 weeks after IH treatment in male dogs. Meanwhile, seminal plasma alkaline phosphatase levels also significantly increased two weeks after IH treatment. These data confirm that IH might induce a two-month inhibition of spermatogenesis in male dogs.