Changes in the Expression of Toll-Like Receptor mRNAs During Follicular Growth and in Response to Lipopolysaccharide in the Ovarian Follicles of Laying Hens

Abstract

Abstract. The aim of this study was to determine the changes in the mRNA expression of Toll-like receptors (TLRs) in hen ovarian follicles during follicular growth and in response to lipopolysaccharide (LPS). White follicles and the fifth largest to largest follicles (WF and F5-F1, respectively) were collected from laying hens. To examine the effects of LPS, the laying hens were treated intravenously with LPS (1 mg/kg BW) 0, 3, 6, 12 and 24 h before examination. Expressions of TLRs and IL-1β in the theca and granulosa layers were examined by semi-quantitative RT-PCR. Immunocytochemistry was performed to identify immunoreactive TLR-4. The theca layer expressed TLR-2, TLR-4, TLR-5 and TLR-7, whereas the granulosa layer expressed only TLR-4 and TLR-5. The expression of TLR-4 and TLR-5 in the theca layer increased significantly during follicular growth. In the granulosa layer, the expression of TLR-5 increased, but that of TLR-4 was unchanged. Expression of TLR-4 increased significantly during the period of 6 to 12 h of LPS treatment in the theca layer and during the period of 12 to 24 h in the granulosa layer of F3. Immunoreaction products for TLR-4 were observed in theca interna and granulosa layers of WF and F5-F1, with the greater amount observed in the theca interna. LPS treatment significantly increased expression of IL-1β in the theca layer after 3 h and in the granulosa layer during the period of 12 to 24 h. These results suggest that TLRs are expressed in ovarian follicles and that TLR-4 and TLR-5 expression increase with the growth of follicles. Enhanced expression of TLR-4 and IL-1β by LPS in the theca and granulosa layers suggests possible roles of TLR in recognition of microorganisms.

Toll-like receptor signaling in hen ovarian granulosa cells is dependent on stage of follicle maturation

“…Similar to the results obtained from F3 (third largest preovulatory follicle), granulosa layers extracted from hens treated intravenously with LPS (Subdei et al 2007), both TLR2 and TLR4 mRNA expressions were increased following treatment with LPS for 20 h, but not at the earlier time point of 4 h. The timing of up-regulation, however, differed for the largest (F1) preovulatory follicle, in which treatment with LPS elicited a significant increase in TLR2 and TLR4 mRNA levels after only 4 h. These data suggest a differential sensitivity to LPS-induced TLR mRNA based on stage of maturation, whereby an accelerated response is elicited in the follicle next to be ovulated.…”

“…This is consistent with a recent report in which i.v. LPS increased ILIB mRNA in granulosa layers from hen preovulatory follicles (Subdei et al 2007). While ILIB was the only cytokine found to be transcriptionally regulated following stimulation with LPS in either study, these data do not preclude additional mediators of LPS-induced cell death.…”

“…Multiple TLRs have been recently described in hen follicles (including the granulosa layer (Subdei et al 2007)), and it has been postulated that TLR-mediated immune responses may participate in the protection of ovarian tissues from invasive pathogens (Shimada et al 2006, Herath et al 2007. Unlike a previous report that indicates the presence of only TLR4 and TLR5 in hen granulosa cells (Subdei et al 2007), TLR4, TLR2, and TLR15 mRNAs were detected in both undifferentiated and differentiated granulosa cells from hen follicles. This finding is significant, because TLR4 and TLR2 (type 2) have been shown to recognize bacterial LPS (Fukui et al 2001, Spiller et al 2007.…”

“…Specifically, recent reports have implied a role for TLR signaling in the regulation of vertebrate ovarian function (Shimada et al 2006, Herath et al 2007, Subdei et al 2007, Liu et al 2008. TLRs have been identified in ovarian cells from multiple species (murine, bovine, chicken), and have been shown in bovine and murine granulosa cells to functionally mediate steroidogenesis and pathogen phagocytosis respectively (Herath et al 2007, Shimada et al 2006.…”

Activation of innate immune system in response to lipopolysaccharide in chicken Sertoli cells

“…Therefore, we developed an in vitro model to investigate the timing of response to LPS on patterns of gene expression in rooster SCs. In hens, it has been reported that the oviduct, as well as ovarian follicular and stromal cells, expresses TLRs, AvBDs, as well as proinflammatory cytokines and chemokines, and the expression of these molecules was upregulated by LPS stimulation (Subedi et al 2007, Abdel Mageed et al 2008, Ozoe et al 2009, Woods et al 2009, Abdelsalam et al 2011, Nii et al 2011. Similar to the female reproductive tract, the gene expression data presented in this study revealed that rooster SCs responded to LPS stimulation.…”