RESUMEN
The expression of hedgehog (Hh) genes, their receptor, and the co-receptor in mice, rat, and bovine ovaries were investigated. RT-PCR of ovarian transcripts in mice showed amplification of transcripts for Indian (Ihh) and desert (Dhh) Hh, patched 1 (Ptch1), and smoothened (Smo) genes. Semi-quantitative RT-PCR and northern blot analyses showed that whole ovarian Ihh and Dhh transcripts decreased 4-24 h after hCG versus 0-48 h after pregnant mares serum gonadotrophin treatment in mice, whereas mouse Ptch1 and Smo transcripts were expressed throughout the gonadotropin treatments. Quantitative real-time RT-PCR (qRT-PCR) revealed that the expression of the Hh-patched signaling system with Ihh mRNA abundance in granulosa cells was greater, whereas Smo and Ptch1 mRNA abundance was less in theca cells of small versus large follicles of cattle. In cultured rat and bovine theca-interstitial cells, qRT-PCR analyses revealed that the abundance of Gli1 and Ptch1 mRNAs were increased (P<0.05) with sonic hedgehog (SHH) treatment. Additional studies using cultured bovine theca cells indicated that SHH induces proliferation and androstenedione production. IGF1 decreased Ihh mRNA abundance in bovine granulosa cells. The expression and regulation of Ihh transcripts in granulosa cells and Ptch1 mRNA in theca cells suggest a potential paracrine role of this system in bovine follicular development. This study illustrates for the first time Hh activation of Gli1 transcriptional factor in theca cells and its stimulation of theca cell proliferation and androgen biosynthesis.
Asunto(s)
Proteínas Hedgehog/metabolismo , Receptores de Superficie Celular/metabolismo , Transducción de Señal/fisiología , Células Tecales/metabolismo , Androstenodiona/biosíntesis , Animales , Bovinos , Células Cultivadas , Femenino , Expresión Génica/efectos de los fármacos , Gonadotropinas Equinas/farmacología , Proteínas Hedgehog/análisis , Proteínas Hedgehog/genética , Humanos , Insulina/farmacología , Factor I del Crecimiento Similar a la Insulina/farmacología , Hormona Luteinizante/farmacología , Ratones , Proteínas Oncogénicas/genética , Proteínas Oncogénicas/metabolismo , Receptores Patched , Receptor Patched-1 , Progesterona/biosíntesis , ARN Mensajero/análisis , Ratas , Receptores de Superficie Celular/análisis , Receptores de Superficie Celular/genética , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Receptor Smoothened , Transactivadores/genética , Transactivadores/metabolismo , Proteína con Dedos de Zinc GLI1RESUMEN
Bone morphogenetic proteins (BMPs) are important for body patterning and morphogenesis, whereas several BMP antagonists regulate the functions of BMPs during embryonic development and tissue differentiation. Protein related to DAN and cerberus (PRDC) is a secreted protein with a cystine knot structure identified by gene trapping in embryonic stem cells. Although PRDC shows sequence homology with proteins of the BMP antagonist family, its biological activity and physiological functions are unclear. We generated recombinant PRDC and its paralog, gremlin, and tested their ability to suppress actions initiated by diverse BMP proteins. Similar to the known BMP antagonist, gremlin, PRDC blocked ligand signaling induced by BMP2 and BMP4 but had minimal effects on reporter gene activation induced by GDF-9, activin, or transforming growth factor-beta. Co-precipitation assays further demonstrated the direct protein-protein interactions between PRDC and BMP2 or BMP4. Reverse transcriptase-PCR analyses indicated that PRDC transcripts are widely expressed showing higher levels in ovary, brain, and spleen. In mouse ovary, PRDC transcripts were increased following gonadotropin treatment. In situ hybridization analyses further indicated that ovarian PRDC transcripts are localized in granulosa cells of selective follicles. In addition, co-treatment with PRDC antagonized the inhibitory effects of BMP4 on the follicle-stimulating hormone stimulation of progesterone production by cultured rat granulosa cells. Thus, PRDC is a potent BMP antagonist with a wide tissue expression pattern, and ovarian PRDC expressed in granulosa cells could be involved in follicular development by antagonizing the actions of theca cell-derived BMPs.