Research

Ribosomal protein mRNAs are translationally-regulated during human dendritic cells activation by LPS

Maurizio Ceppi^1,2,3,6 , Giovanna Clavarino^1,2,3 , Evelina Gatti^1,2,3 , Enrico K Schmidt^1,2,3 , Aude de Gassart^1,2,3 , Derek Blankenship⁵ , Gerald Ogola⁵ , Jacques Banchereau⁴ , Damien Chaussabel⁴ and Philippe Pierre^1,2,3

¹  Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Case 906, 13288 Marseille cedex 9, France

²  INSERM, U631, 13288 Marseille, France

³  CNRS, UMR6102, 13288 Marseille, France

⁴  Baylor Institute for Immunology Research (BIIR), 3434 Live Oak, Dallas, TX 75204, USA

⁵  Baylor Institute for Health Care Research and Improvement, 8080 North Central Expressway, Dallas, TX 75206, USA

⁶  Genomic Vision, Paris Santé Cochin, 75014 Paris, France

author email corresponding author email

Immunome Research 2009, 5:5doi:10.1186/1745-7580-5-5

Published:	27 November 2009

Abstract

Background

Dendritic cells (DCs) are the sentinels of the mammalian immune system, characterized by a complex maturation process driven by pathogen detection. Although multiple studies have described the analysis of activated DCs by transcriptional profiling, recent findings indicate that mRNAs are also regulated at the translational level. A systematic analysis of the mRNAs being translationally regulated at various stages of DC activation was performed using translational profiling, which combines sucrose gradient fractionation of polysomal-bound mRNAs with DNA microarray analysis.

Results

Total and polysomal-bound mRNA populations purified from immature, 4 h and 16 h LPS-stimulated human monocyte-derived DCs were analyzed on Affymetrix microarrays U133 2.0. A group of 375 transcripts was identified as translationally regulated during DC-activation. In addition to several biochemical pathways related to immunity, the most statistically relevant biological function identified among the translationally regulated mRNAs was protein biosynthesis itself. We singled-out a cluster of 11 large ribosome proteins mRNAs, which are disengaged from polysomes at late time of maturation, suggesting the existence of a negative feedback loop regulating translation in DCs and linking ribosomal proteins to immuno-modulatory function.

Conclusion

Our observations highlight the importance of translation regulation during the immune response, and may favor the identification of novel protein networks relevant for immunity. Our study also provides information on the potential absence of correlation between gene expression and protein production for specific mRNA molecules present in DCs.