Effects of lipopolysaccharide and interleukins on the expression of avian β-defensins in hen ovarian follicular tissue.

The aim of this study was to determine the mechanism by which expression of avian β-defensins (AvBD) in the follicular theca tissue was regulated. It was examined whether their expression was stimulated directly by LPS or indirectly through proinflammatory cytokines (IL-1β and IL-6) induced by LPS. Theca tissues of ovarian follicles were collected from White Leghorn hens. The specimens of those theca tissues were cultured in TCM-199 culture medium and stimulated by lipopolysaccharide from Salmonella minnesota (LPS), recombinant chicken IL-1β, or recombinant chicken IL-6. In the first experiment, changes in the expression of IL-1β, IL-6, AvBD10, and AvBD12 in response to LPS stimulation were examined by quantitative reverse-transcription PCR. The AvBD10 and 12 had been known to be expressed in the theca. In the second experiment, changes in the expression of AvBD10 and 12 in response to recombinant chicken IL-1β or IL-6 stimulation were examined by quantitative reverse-transcription PCR. Density of AvBD12 protein after IL-1β stimulation that showed changes in the gene expression was analyzed by Western blotting. In the first experiment, LPS was able to induce IL-1β and IL-6, but not AvBD10 or AvBD12. In the second experiment, IL-1β was able to upregulate significantly the expression of AvBD12 mRNA and protein. However, IL-6 did not exert significant effects on the expression of AvBD10 and AvBD12. It is suggested that LPS may stimulate theca cells to produce proinflammatory cytokines, whereas, in turn, IL-1β stimulates those cells to synthesize AvBD12, which may be able to attack infectious gram-negative bacteria.