Identification of novel monosodium urate crystal-induced mRNAs

ABSTRACT: Objective. To identify novel monosodium urate (MSU) crystal-induced mRNAs by transcript profiling of isolated murine air pouch membranes. Methods. Nine hours after injecting crystals into air pouches, membranes were meticulously dissected away from the adjacent soft tissues. mRNA expression differences between inflamed and control membranes were determined by oligonucleotide microarray analysis. Induction of selected mRNAs was validated by real-time relative quantitative reverse transcriptase PCR (qPCR) in pouch membranes and murine peritoneal macrophages. Results. Eleven of the 12 most highly upregulated mRNAs related to innate immunity and inflammation. They included mRNAs encoding histidine decarboxylase (the enzyme that synthesizes histamine), interleukin (IL)-6, the cell surface receptors PUMA-g and TREM-1, and the polypeptides Irg1 and PROK-2. MSU crystals induced dramatic rises in these mRNAs in the pouch membrane within 3-8 hours after the surge in pro-inflammatory cytokine (IL-6, IL-1beta and TNFalpha) and immediate early gene (Egr-1) transcription, which occurred 1h after crystal injection. MSU crystals induced these mRNAs in cultured macrophages with similar kinetics but lower fold changes. In keeping with their downregulation by MSU crystals according to the microarrays, qPCR confirmed that TREM-2 and granzyme D mRNAs decreased 79% and 94%, respectively, in MSU crystal inflamed membranes. Conclusions. This analysis disclosed several genes previously not implicated in MSU crystal inflammation. Their rise after the early surge in cytokine mRNAs suggests that they may, for instance, amplify or perpetuate inflammation. Transcript profiling of the isolated air pouch membrane promises to be a powerful tool to identify genes acting at different stages of inflammation.

ORGANISM(S): Mus musculus

PROVIDER: GSE11498 | GEO | 2008/05/23

SECONDARY ACCESSION(S): PRJNA106315

REPOSITORIES: GEO