Effects of ODC on polyamine metabolism, hormone levels, cell proliferation and apoptosis in goose ovarian granulosa cells

Abstract

Ornithine decarboxylase (ODC) plays an indispensable role in the process of polyamine biosynthesis. Polyamines are a pivotal part of living cells and have diverse roles in the regulation of cell proliferation and apoptosis, aging and reproduction. However, to date, there have been no reports about ODC regulating follicular development in goose ovaries. Here, we constructed ODC siRNA and overexpression plasmids and transfected them into goose primary granulosa cells (GCs) to elucidate the effects of ODC interference and overexpression on the polyamine metabolism, hormone levels, cell apoptosis and proliferation of granulosa cells. After interfering with ODC in GCs, the mRNA and protein levels of ODC and the content of putrescine were greatly decreased (P < 0.05). When ODC was overexpressed, ODC mRNA and protein levels and putrescine content were greatly increased (P < 0.05). The polyamine-metabolizing enzyme genes ornithine decarboxylase antizyme 1 (OAZ1) and spermidine / spermine-N1-acetyltransferase (SSAT) were significantly increased, and spermidine synthase (SPDS) was significantly decreased when ODC was downregulated (P < 0.05). OAZ1, SPDS and SSAT were significantly increased when ODC was upregulated (P < 0.05). In addition, after interference with ODC, progesterone (P4) levels in the culture medium of GCs increased greatly (P < 0.05), while the overexpression of ODC caused the P4 level to decrease significantly (P < 0.05). After ODC downregulation, granulosa cell activity was significantly reduced, the apoptosis rate was significantly increased, and the BCL-2 / BAX ratio was downregulated (P < 0.05). Under ODC overexpression, the activity of GCs was notably increased, the apoptosis rate was significantly reduced, and the BCL-2 / BAX protein ratio was upregulated (P < 0.05). Our study successfully induced ODC interference and overexpression in goose ovarian GCs, and ODC regulated mainly putrescine content in GCs with a slight influence on spermidine and spermine. Moreover, ODC participated in the adjustment of P4 levels in the culture medium of GCs, promoted granulosa cell proliferation and inhibited granulosa cell apoptosis.

Keywords: apoptosis; granulosa cells; ornithine decarboxylase; polyamine; proliferation.