title: Hypoxia modifies the transcriptome of primary human monocytes: modulation of novel immune-related genes and identification of CC-chemokine ligand 20 as a new hypoxia-inducible gene.
abstract: Peripheral blood monocytes migrate to and accumulate in hypoxic areas of inflammatory and tumor lesions. To characterize the molecular bases underlying monocyte functions within a hypoxic microenvironment, we investigated the transcriptional profile induced by hypoxia in primary human monocytes using high-density oligonucleotide microarrays. Profound changes in the gene expression pattern were detected following 16 h exposure to 1% O(2), with 536 and 677 sequences showing at least a 1.5-fold increase and decrease, respectively. Validation of this analysis was provided by quantitative RT-PCR confirmation of expression differences of selected genes. Among modulated genes, 74 were known hypoxia-responsive genes, whereas the majority were new genes whose responsiveness to hypoxia had not been previously described. The hypoxic transcriptome was characterized by the modulation of a significant cluster of genes with immunological relevance. These included scavenger receptors (CD163, STAB1, C1qR1, MSR1, MARCO, TLR7), immunoregulatory, costimulatory, and adhesion molecules (CD32, CD64, CD69, CD89, CMRF-35H, ITGB5, LAIR1, LIR9), chemokines/cytokines and receptors (CCL23, CCL15, CCL8, CCR1, CCR2, RDC1, IL-23A, IL-6ST). Furthermore, we provided conclusive evidence of hypoxic induction of CCL20, a chemoattractant for immature dendritic cells, activated/memory T lymphocytes, and naive B cells. CCL20 mRNA up-regulation was paralleled by increased protein expression and secretion. This study represents the first transcriptome analysis of hypoxic primary human monocytes, which provides novel insights into monocyte functional behavior within ischemic/hypoxic tissues. CCL20 up-regulation by hypoxia may constitute an important mechanism to promote recruitment of specific leukocyte subsets at pathological sites and may have implications for the pathogenesis of chronic inflammatory diseases.
authors.affiliation: Laboratory of Molecular Biology, G. Gaslini Institute, Genova, Italy. mcbosco1@virgilio.it
authors.forename: Maria Carla
authors.initials: MC
authors.lastname: Bosco
authors.forename: Maura
authors.initials: M
authors.lastname: Puppo
authors.forename: Clara
authors.initials: C
authors.lastname: Santangelo
authors.forename: Luca
authors.initials: L
authors.lastname: Anfosso
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pfeffer
authors.forename: Paolo
authors.initials: P
authors.lastname: Fardin
authors.forename: Florinda
authors.initials: F
authors.lastname: Battaglia
authors.forename: Luigi
authors.initials: L
authors.lastname: Varesio
mesh_terms: D015687:Cell Hypoxia / Q000235:genetics* / Q000276:immunology; D002478:Cells, Cultured; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation / Q000276:immunology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D008024:Ligands; D019402:Macrophage Inflammatory Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism*; D005810:Multigene Family / Q000276:immunology; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000276:immunology
chemical_list: C108355:CCL20 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; D008024:Ligands; D019402:Macrophage Inflammatory Proteins