Coordinate posttranscriptional regulation of asthma genes by the RNA binding protein HuR (79.6)

Abstract

Abstract Traditional microarray analysis has uncovered a variety of genes involved in diseases such as asthma. However, it may potentially miss important genes due to the discordance between steady state mRNA levels and protein products. Posttranscriptional events conferred by RNA binding proteins (RBPs) contribute to this phenomenon. We have developed novel techniques known as RIP-on-Chip (microchip) which allow for the immunoprecipitation and identification of in vivo mRNA targets bound to RBPs. We study the RBP HuR, which regulates many early response genes including cytokines and chemokines. Using RIP-on-Chip, HuR has been demonstrated to associate and regulate many asthma relevant genes including recently identified genes IL-4 and IL-13. We have extended this assay to solid organ tissues. Employing the standard ovalbumin model of allergic airway inflammation, coupled to genome-wide arrays (47,000 genes) we have identified in vivo HuR targets in lungs of naïve, alum only or ova challenged mice. Remarkably, there are only 12 HuR targets (2 fold or greater) up regulated in ova and alum immunized over alum alone mice. Some are known HuR target genes such as TLR4 and IL-13; others are potentially novel asthma genes. Furthermore, we have created a transgenic mouse which over expresses HuR in CD4+ T cells. In the allergic airway inflammation model these mice have an increase in lung lymphocyte infiltration when compared to wild-type littermates, further implicating coordinate posttranscriptional gene regulation and HuR in allergic airway inflammation.