Lipopolysaccharide induces SBD-1 expression via the P38 MAPK signaling pathway in ovine oviduct epithelial cells.

Dafu Zhi,Guifang Cao,Qin Yan,Yan Li,Qi Li,Lixin Ren,Moning Liu,Shan Cong,Xinxin Zheng,Fuxiang Bao

doi:10.1186/s12944-016-0294-4

Dafu Zhi, Guifang Cao + Show 8 more

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https://doi.org/10.1186/s12944-016-0294-4

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Abstract

BackgroundBeta defensins are secreted from ovine oviduct epithelial cells (OOECs) in response to microbial infection, and are potential alternatives to antibiotic agents in the treatment of microorganism infection, particularly given the abuse of antibiotic agents and the increasing number of drug-resistant bacteria. The aberrant expression of defensins may result in disorders involving organ and oviduct inflammation, such as salpingitis.MethodsIn the present study, we investigated the effects of LPS on the mRNA expression levels of sheep β-defensin-1 (SBD-1) in ovine oviduct epithelial cells. The OOECs in vitro culturing system were established and treated with different concentrations of LPS for indicated time. In addition, MAPK inhibitors and TLR4 antibodies were pretreated to investigate the potential mechanism which involves in LPS regulating SBD-1 expression.ResultsLPS markedly upregulated SBD-1 expression in a concentration- and time-dependent manner. Treatment with 100 ng/mL LPS resulted in the phosphorylation of JNK, ERK and P38 MAPK. Interestingly, the LPS stimulated SBD-1 expression was attenuated by pretreatment with the P38 MAPK inhibitors SB203580 and SB202190 but not the JNK inhibitor SP600125, while the ERK inhibitor PD98059 had a minor effect. Furthermore, treatment with a Toll-like receptor 4 (TLR4) neutralizing antibody significantly decreased P38 MAPK phosphorylation and LPS induced SBD-1 expression.ConclusionsTogether, these findings suggest that SBD-1 is upregulated by LPS via the TLR4 receptor, mainly through the P38 MAPK signaling pathway in ovine oviduct epithelial cells to protect the ovine oviduct epithelium from pathogen invasion.Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-016-0294-4) contains supplementary material, which is available to authorized users.

Highlights

Beta defensins are secreted from ovine oviduct epithelial cells (OOECs) in response to microbial infection, and are potential alternatives to antibiotic agents in the treatment of microorganism infection, given the abuse of antibiotic agents and the increasing number of drug-resistant bacteria
LPS induces sheep β-defensin-1 (SBD-1) mRNA expression To identify whether the isolated cells were oviduct epithelial cells, sections of cells were immunolabeled with oviduct epithelial cell marker, CK-18, and nuclear marker, Hochest 33342 by immunofluorescence analysis
The results of quantitative RT-PCR demonstrated that treatment with LPS (10–1000 ng/mL) for 24 h caused a concentration-dependent increase in the SBD-1 mRNA expression (Fig. 1b)

Summary

Introduction

Beta defensins are secreted from ovine oviduct epithelial cells (OOECs) in response to microbial infection, and are potential alternatives to antibiotic agents in the treatment of microorganism infection, given the abuse of antibiotic agents and the increasing number of drug-resistant bacteria. The aberrant expression of defensins may result in disorders involving organ and oviduct inflammation, such as salpingitis. The aberrant expression of defensins may result in disorders involving organ and oviduct. As an important component of the innate immune system, defensins have a lethal effect on both gram-negative and gram-positive bacteria, as well as on viruses and fungi [5,6,7]. Charged defensins can bind to the negatively charged bacterial surface. The hydrophobic ends of defensins can bind to the phospholipid membrane of bacteria, damage its structure and cause the efflux of bacterial contents, which leads to bacterial death [8, 9]

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