Ribosomal protein S3 gene silencing protects against experimental allergic asthma

Background and Purpose Ribosomal protein S3 (RPS3) is a 40S ribosomal protein of the S3P family essential for executing protein translation. RPS3 has recently been found to interact with the p65 subunit of the NF-κB complex, and promote p65 DNA-binding activity. Persistent activation of the NF-κB pathway is evident in allergic asthma. We hypothesized that gene silencing of lung RPS3 can ameliorate allergic airway inflammation. Experimental Approach Gene silencing efficacy of RPS3 siRNA was screened in three different mouse cell lines by real-time PCR and immunoblotting. Protective effects of intratracheal RPS3 siRNA in a house dust mite (HDM) mouse asthma model determined by measuring cell counts in lung lavage fluid and lung sections, lung cytokine profiles and airway hyperresponsiveness (AHR). Key Results RPS3 siRNA markedly knocked down RPS3 levels in all mouse cell lines tested, and in mouse lung tissues, blocked TNF-α- or HDM-induced mediators release by the cultured cells, and reduced eosinophil counts in lung lavage fluid from HDM mouse asthma model. RPS3 siRNA abated HDM-induced airway mucus hypersecretion, cytokine production, and serum IgE elevation. Moreover, RPS3 knockdown significantly suppressed methacholine-induced AHR in experimental asthma. RPS3 siRNA disrupted TNF-α-induced NF-κB activation in an NF-κB reporter gene assay in vitro, and mitigated nuclear accumulation of p65 subunit and p65 transcriptional activation in HDM-challenged lungs and cells. Conclusions and Implications We reported here that RPS3 gene silencing ameliorated experimental asthma probably via interruption of the NF-κB activity, postulating that RPS3 is a novel therapeutic target for allergic airway inflammation.