Equus β-Defensin-1 Regulates Innate IMMUNE Response in -Infected Mouse Monocyte Macrophage.

Beta-defensin-1 (BD-1) is among the class of antibacterial peptides that are rich in disulfide bonds, have direct antibacterial activity and showed enhanced expression following external stimulation. However, existing research studies only treated BD-1 to cell models without stimulation from pathogen-associated molecular patterns (PAMPs), which will further influence our understanding of the role of BD-1. In this study, we map the tissue distribution of Equus BD-1 (i.e., , , and ) and compare their expression levels in various tissues. We further characterize the three kinds of Equus BD-1 by analyzing their full-length cDNA. We showed that , , and have an identical (100%) open reading frame (ORF). The ORF encoding OEBD-1 expressed the ORF in the Top10 expression system. This expression system was combined with an -infected J774A.1 macrophage cell line to determine the influence on innate immune mediator expression. Using this expression model system, it was determined that the OEBD-1 protein enhanced IL-6 and TNF-α secretion. It can also promote , , , , and mRNA expression. Moreover, OEBD-1 upregulates phosphorylation of ATK, Syk and IκB-α. In addition, OEBD-1 enhances the macrophage's ability to phagocytose . In conclusion, Equus BD-1 was shown to play an essential role in macrophage-involved innate immune responses in an in vitro system.