The crosstalk between Dectin1 and TLR4 via NF-κB subunits p65/RelB in mammary epithelial cells

Mammary epithelial cells (MECs), as part of the functional unit of the udder, are not only responsible for the synthesis of many components in milk that provide necessary nutritional and immunological support to the offspring, but also playing essential roles in the reaction to mastitis pathogens and the initiation of the immune signaling pathway. There are contributions of MECs to the signaling and production of pathogen associated molecular patterns (PAMPs) such as LPS, lipoteichoic acid (LTA), and β-glucans, but the crosstalk of different PAMPs induces signalings and productions in rat MEC that need further study. In the present study, we have demonstrated that β-glucan up-regulates Dectin1 and LPS up-regulates TLR4 directly, as confirmed by generation of siDectin1 and siTLR4 in rat MECs. Then our results have described that either β-glucan or LPS can activate RelB and/or p65 in rat MECs. Furthermore, the association of p65 and RelB has been analyzed that collaboration of β-glucan and LPS promotes p65/RelB heterodimers, producing inflammatory responses in rat MECs. In conclusion, summary of our present results suggests that β-glucan can be considered as a potential immuno-modulator, which s with TLR4 via NF-κB subunits to initiate and regulate the innate immunity in rat MECs.