Identification of High and Low Responders to Lipopolysaccharide in Normal Subjects: An Unbiased Approach to Identify Modulators of Innate Immunity

Abstract

LPS stimulates a vigorous inflammatory response from circulating leukocytes that varies greatly from individual to individual. The goal of this study was to use an unbiased approach to identify differences in gene expression that may account for the high degree of interindividual variability in inflammatory responses to LPS in the normal human population. We measured LPS-induced cytokine production ex vivo in whole blood from 102 healthy human subjects and identified individuals who consistently showed either very high or very low responses to LPS (denoted lpshigh and lpslow, respectively). Comparison of gene expression profiles between the lpshigh and lpslow individuals revealed 80 genes that were differentially expressed in the presence of LPS and 21 genes that were differentially expressed in the absence of LPS (p < 0.005, ANOVA). Expression of a subset of these genes was confirmed using real-time RT-PCR. Functional relevance for one gene confirmed to be expressed at a higher level in lpshigh, adipophilin, was inferred when reduction in adipophilin mRNA by small interfering RNA in the human monocyte-like cell line THP-1 resulted in a modest but significant reduction in LPS-induced MCP-1 mRNA expression. These data illustrate a novel approach to the identification of factors that determine interindividual variability in innate immune inflammatory responses and identify adipophilin as a novel potential regulator of LPS-induced MCP-1 production in human monocytes.

Effects of EPA and DHA on lipid droplet accumulation and mRNA abundance of PAT proteins in caprine monocytes

“…This activity can have a profound impact on monocyte immune functions, since a relationship between perilipin expression and innate immunity reactions has been recently demonstrated. For example, PLIN2 expression is increased during innate immunity response against leprosy (Mattos et al, 2011), and regulates MCP1 production by human monocytes (Wurfel et al, 2005). PLIN2 was also found to be involved in dendritic cell antigen presentation (Bougnères et al, 2009).…”

The Duffy Antigen Modifies Systemic and Local Tissue Chemokine Responses following Lipopolysaccharide Stimulation

“…Incubation of whole blood with medium alone showed minimal cytokine production (data not shown). We have previously described the temporal stability of the LPS-induced cytokine expression phenotype in whole blood (22).…”

“…We have previously reported the description of the study subjects (22). Briefly, healthy subjects between 18 and 65 years of age gave written informed consent for the studies and were recruited from the University of Washington community.…”

“…The whole blood assay has been previously described (22). Briefly, whole blood was collected from fasting subjects between 8:00 and 10:00 a.m.…”

Inflammatory Bowel Disease G-Prote in Coupled Receptors (GPCRs) Expression Profiling with Microfluidic Cards

“…In a similar approach conducted with larger arrays, the same trend was observed i.e. LPS represses 1125 genes out of 1868 differentially expressed genes (Wurfel et al 2005). Among the overexpressed genes, these authors note the presence of key players in the inflammatory response, primarily cytokines and chemokines.…”