Gene silencing of receptor-interacting protein 2 protects against cigarette smoke-induced acute lung injury.

BACKGROUND AND PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by progressive alveolar damage and generally irreversible airflow limitation. Nuclear factor-κB (NF-κB) plays a critical role in COPD pathogenesis. Receptor-interacting protein 2 (Rip2), a 60 kDa adaptor protein, is a positive regulator of NF-κB pathway and also an inducible transcriptional product of NF-κB activation. We sought to investigate if Rip2 gene silencing could protect against cigarette smoke (CS)-induced acute lung injury. EXPERIMENTAL APPROACH: Gene silencing efficacy of Rip2 siRNA was characterized in mouse macrophage and mouse lung epithelial cell lines, and in a CS-induced acute lung injury mouse model. Bronchoalveolar lavage (BAL) fluid cell counts, levels of pro-inflammatory and oxidative damage markers, lung section inflammatory and epithelium thickness scorings, and nuclear NF-κB translocation were measured. KEY RESULTS: CS was found to upregulate Rip2 level in mouse lungs. Rip2 siRNA was able to suppress Rip2 levels in both macrophage and lung epithelial cell lines and in mouse lungs, block CS extract (CSE)-induced mediator release by the cultured cells, and abate neutrophil counts in BAL fluid from CS-challenged mice. Rip2 siRNA suppressed CS-induced inflammatory and oxidative damage markers, and nuclear p65 accumulation and transcriptional activation in lung tissues. Besides, Rip2 siRNA was able to disrupt CSE-induced NF-κB activation in a NF-κB reporter gene assay. CONCLUSIONS AND IMPLICATIONS: Taken together, we report for the first time that Rip2 gene silencing ameliorated CS-induced acute lung injury probably via disruption of the NF-κB activity, postulating that Rip2 may be a novel therapeutic target for COPD.

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 implementing 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: The 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 were 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 release of mediators by the cultured cells and reduced eosinophil counts in lung lavage fluid from the HDM mouse asthma model. RPS3 siRNA lessened 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 a NF-κB reporter gene assay in vitro and prevented the nuclear accumulation of p65 subunit and p65 transcriptional activation in HDM-challenged lungs and cells. CONCLUSIONS AND IMPLICATIONS: RPS3 gene silencing ameliorates experimental asthma, probably by disrupting NF-κB activity. RPS3 could be a novel therapeutic target for allergic airway inflammation.

Towards evidence-based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 2: C-reactive protein in the diagnosis of bacteraemia.

A short-cut review was carried out to establish the sensitivity and specificity of CRP as a tool for diagnosing bacteraemia. Three studies were directly relevant to the question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. The clinical bottom line suggests that CRP is not a useful tool in the initial diagnosis of severe bacterial infection.

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. C Reactive Protein and the diagnosis of intracranial infection.

A short cut review was carried out to determine whether measuring C Reactive Protein might help in the diagnosis of intracranial infection in a patient presenting to the Emergency department with an acute headache. 62 papers were found, but none answered the question. The clinical bottom line is that there doesn't appear to be any evidence for, or against, the use of C Reactive Protein in the diagnosis of intracranial infection in patients presenting to the Emergency department with an acute headache.