Microarray analysis of lipopolysaccharide-treated human neutrophils

Abstract

Neutrophils respond to infection by degranulation, release of reactive oxygen intermediates, and secretion of chemokines and cytokines; however, activation of neutrophil transcriptional machinery has been little appreciated. Recent findings suggest that gene expression may represent an additional neutrophil function after exposure to lipopolysaccharide (LPS). We performed microarray gene expression analysis of 4,608 mostly nonredundant genes on LPS-stimulated human neutrophils. Analysis of three donors indicated some variability but also a high degree of reproducibility in gene expression. Twenty-eight verifiable, distinct genes were induced by 4 h of LPS treatment, and 13 genes were repressed. Genes other than cytokines and chemokines are regulated; interestingly, genes involved in cell growth regulation and survival, transcriptional regulation, and interferon response are among those induced, whereas genes involved in cytoskeletal regulation are predominantly repressed. In addition, we identified monocyte chemoattractant protein-1 as a novel LPS-regulated chemokine in neutrophils. Included in these lists are five clones with no defined function. These data suggest molecular mechanisms by which neutrophils respond to infection and indicate that the transcriptional potential of neutrophils is greater than previously thought.

Lipopolysaccharide-induced c-Jun NH2-terminal Kinase Activation in Human Neutrophils

“…Because we have recently observed increased expression of MCP-1 mRNA upon LPS stimulation in neutrophils (54), and the induction of AP-1, of which c-Jun is one component, is important for the expression of MCP-1 mRNA (55, 56), we hypothesized that LPS may induce the activation of JNK. Isolated human neutrophils were incubated under non-suspended conditions for 60 min, then exposed to LPS, followed by immunoprecipitation of JNK1 and an in vitro kinase assay using recombinant c-Jun 1-79 as an exogenous substrate.…”

“…Recently we have shown that in addition to the up-regulation of these pro-inflammatory mediators, neutrophils have increased expression and release of MCP-1 after LPS stimulation (54). The transcriptional regulation of MCP-1 expression has been shown to be controlled primarily through the activation of AP-1, of which c-Jun is a prototypical component (55,56).…”

Lipopolysaccharide Stimulates p38-dependent Induction of Antiviral Genes in Neutrophils Independently of Paracrine Factors

“…In summary, gene expression analysis of LPS-stimulated neutrophils has led to the detection of an unexpected set of antiviral genes (32,38). In contrast to other cell types (36,37,83), such as macrophages, the LPS induction of ISGs in neutrophils does not involve secretion of mediators, including IFN␣/␤, or STAT activation.…”

“…In this way, antiviral gene expression is accomplished in response to bacterial infection. We recently described (32,38) the regulation of ISGs in LPS-treated neutrophils. Here we investigated the mechanisms by which neutrophils induce ISGs in response to LPS.…”

Gene Expression Profiling of Polymorphonuclear Leukocytes Treated with the Culture Filtrate of Aspergillus fumigatus and Gliotoxin

“…Analysis of gene expression in PMNs after lipopolysaccharide (LPS) treatment (20) suggests that PMNs exert their bioactivity not only through release of pre-made molecules but also through a transcriptional response. In addition, within 2 hr of exposure to bacteria, a dramatic change in the levels of several hundred mRNAs occurs in PMNs (32).…”