Effect of the rhesus theta defensin-1 (RTD-1) on gene expression in human monocytic THP-1 cells. [I]

Theta defensins are unique since they are the only cyclic peptides in the animal kingdom. The theta defensin, Rhesus theta defensin (RTD)-1, first isolated from rhesus macaque neutrophils as a broad-spectrum antimicrobial peptide was subsequently found to regulate gene expression and immune signaling pathways in cell culture and animal models of immune mediated diseases. To gain insights into RTD-1 regulation, we performed RNA sequencing (RNA-seq) to determine the effect of RTD-1 on global gene expression in THP-1 monocytes. Differential gene expression analysis revealed RTD-1 mediated stimulation of interferon and antiviral gene expression pathways potentially priming cells for resistance to viral infections. Overall design: Monocytic THP-1 cells were treated with 1, 3, 10 µg/ml RTD-1 or with the vehicle (0.01 % acetic acid) for 20 h in the presence or absence of 100 ng/ml Salmonella enterica LPS in RPMI containing 1% FBS and 1% penicillin/streptomycin medium. The RNA isolated from these cells was used for gene expression profiling to identify differentially expressed genes between RTD-1 treated and untreated cells.