Effect of Oaz1 overexpression on goose ovarian granulosa cells

Ornithine decarboxylase antizyme 1 (OAZ1) regulates both polyamine biosynthesis and transport and acts as a tumor suppressor because of its functions in the regulation of cell proliferation, apoptosis and growth. However, the roles of OAZ1 in the regulation of polyamine metabolism, cell proliferation, apoptosis and hormone receptor expression in granulosa cells (GCs) from geese have not been determined. To define the roles of OAZ1 in primary GCs, we constructed and transfected an Oaz1 overexpression vector with a thymidine deletion into primary GCs. Oaz1 overexpression induced 65 and 30% decreases in the putrescine and spermidine contents, respectively, 225% increase in the spermine content and up-regulated the expression levels of genes associated with polyamine metabolism (but Oaz2). The Ccnd1, Pcna, Bax and Caspase 3 mRNA expression levels in GCs overexpressing Oaz1 were significantly higher than the expression levels in the vehicle group (p < 0.05). Additionally, a slight increase in the E2 concentration in the culture medium and enhanced Er, Fshr and Lhr expression were observed in the GCs 24 h after Oaz1 overexpression (p < 0.05). These data suggested that Oaz1 up-regulated the expression of genes related to polyamine metabolic enzymes and reproductive hormone receptors, disturbed intracellular polyamine homeostasis, and affected the transcription of genes associated to cell proliferation and apoptosis in goose primary GCs. Taken together, our results indicate that modifying polyamine metabolism by Oaz1 may interfere with the expression of genes involved in cell proliferation, apoptosis and responsiveness of ovary toward hormones in goose GCs.