RESUMO
This study examined the molecular mechanism by which BMP-4 inhibits progesterone production and the expression of genes involved in steroidogenesis. Granulosa cells were cultured in medium with or without BMP-4 for 0-96 h. BMP-4 inhibited progesterone secretion in granulosa cells and suppressed the expression of steroidogenic acute regulatory protein (StAR) at the mRNA and protein levels, whereas BMP-4 did not affect the proliferation of granulosa cells. In addition, we found that BMP-4 affected the expression of SR-B1 mRNA but not LDL-R in granulosa cells. To examine the protein-DNA interaction at specific sites within the StAR gene promoter, we used the quantitative real-time PCR and the ChIP technique. We demonstrated that BMP-4 suppresses the acetylation of histone H3 associated with the StAR promoter region at 48 and 72 h of culture in bovine granulosa cells. Our results showed for the first time that BMP-4 inhibited the acetylation of histone H3 associated with the StAR promoter region in bovine granulosa cells. Taken together, we propose that the inhibition of the acetylation of histone H3 associated with the StAR promoter region by BMP-4 may be one of the inhibitory molecular mechanisms of progesterone synthesis in granulosa cells. Our data suggested that theca cell-derived BMP-4 is important as a regulator of steroid hormone synthesis in granulosa cells during follicular development in the mammalian ovary.
Assuntos
Proteína Morfogenética Óssea 4/metabolismo , Células da Granulosa/metabolismo , Histonas/metabolismo , Fosfoproteínas/metabolismo , Progesterona/biossíntese , 3-Hidroxiesteroide Desidrogenases/genética , Acetilação , Animais , Antígenos CD36/genética , Bovinos , Proliferação de Células , Células Cultivadas , Enzima de Clivagem da Cadeia Lateral do Colesterol/genética , Imunoprecipitação da Cromatina , Regulação para Baixo , Feminino , Humanos , Fosfoproteínas/genética , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Receptores de LDL/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de TempoRESUMO
We investigated the expression of genes and transcription factors associated with steroidogenesis during the luteinization of granulosa cells isolated from bovine small follicles. Granulosa cells produced progesterone when cultivated in a culture medium including serum and attached to the substrate and began to display an elongated or fibroblastic aspect within 24 h of culture. We observed an increase in the number of granulosa cells at the same time. P450arom expression in the cultured granulosa cells had decreased at 24 h compared with 0 h of culture, and afterward was maintained at a low level. This expression was consistent with the decline of E2 concentration in the medium. Expression of StAR and P450scc mRNAs in the cultured granulosa cells was significantly increased at 72 h compared with 0 h of culture. Although the expression of Ad4BP/SF-1 mRNA began to increase during period between 48 and 72 h of culture, protein expression of Ad4BP/SF-1 remained at a constant level throughout the culture period. DAX-1 mRNA expression had decreased at 24 h of culture and remained at a low level. In parallel with this expression, the protein expression of DAX-1 began to decrease between 24 and 48 h of culture and then remained at a low level. Histone H3 acetylation of the StAR promoter region was observed at 72 h of culture period. Our data suggested that the decrease of Dax-1 transcription factor and the increase in histone H3 acetylation may play important roles in progesterone synthesis in luteinizing granulosa cells.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Células da Granulosa/metabolismo , Histonas/metabolismo , Luteinização , Receptores do Ácido Retinoico/metabolismo , Proteínas Repressoras/metabolismo , Acetilação , Animais , Bovinos , Células Cultivadas , Receptor Nuclear Órfão DAX-1 , Proteínas de Ligação a DNA/genética , Feminino , Regulação da Expressão Gênica , Células da Granulosa/citologia , Células da Granulosa/fisiologia , Cinética , Progesterona/biossíntese , Regiões Promotoras Genéticas , Receptores do Ácido Retinoico/genética , Proteínas Repressoras/genética , Fatores de Transcrição/genéticaRESUMO
Active angiogenesis and progesterone (P) synthesis occur in parallel during development of the corpus luteum (CL). Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are known to stimulate angiogenesis and P synthesis in vitro. The aim of the present study was to investigate the impact of bFGF or VEGF on the CL development in the cow by using a specific antibody against bFGF or VEGF. bFGF antibody, VEGF antibody, or saline as a control (n = 4 cows/treatment) were injected directly into the CL immediately after ovulation (Day 1), and the treatment was continued for 3 times/day over 7 days. Luteal biopsies were applied on Day 8 of the estrous cycle to determine the expression of genes associated with P synthesis and angiogenesis. Intraluteal injections with the bFGF antibody or the VEGF antibody markedly decreased the CL volume, plasma P concentration and StAR mRNA expression. bFGF antibody treatment decreased the mRNA expression of bFGF, FGF receptor-1, VEGF120, and angiopoietin (ANPT)-1, and increased ANPT-2/ANPT-1 ratio. However, VEGF antibody treatment decreased ANPT-2 mRNA expression and ANPT-2/ANPT-1 ratio. These results indicate that local neutralization of bFGF or VEGF changes genes regulating angiogenesis and P synthesis, and remarkably suppresses the CL size and P secretion during the development of CL in the cow, supporting the concept that bFGF and VEGF control the CL formation and function.
Assuntos
Anticorpos/farmacologia , Bovinos/fisiologia , Corpo Lúteo/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Angiopoietina-1/genética , Angiopoietina-1/metabolismo , Angiopoietina-2/genética , Angiopoietina-2/metabolismo , Animais , Corpo Lúteo/crescimento & desenvolvimento , Corpo Lúteo/metabolismo , Corpo Lúteo/fisiologia , Ciclo Estral/sangue , Ciclo Estral/efeitos dos fármacos , Ciclo Estral/genética , Feminino , Fator 2 de Crescimento de Fibroblastos/imunologia , Fator 2 de Crescimento de Fibroblastos/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Progesterona/sangue , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/imunologia , Fator A de Crescimento do Endotélio Vascular/fisiologiaRESUMO
As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.
