Enhancing tristetraprolin activity reduces the severity of cigarette smoke-induced experimental chronic obstructive pulmonary disease.

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a progressive disease that causes significant mortality and morbidity worldwide and is primarily caused by the inhalation of cigarette smoke (CS). Lack of effective treatments for COPD means there is an urgent need to identify new therapeutic strategies for the underlying mechanisms of pathogenesis. Tristetraprolin (TTP) encoded by the gene is an anti-inflammatory protein that induces mRNA decay, especially of transcripts encoding inflammatory cytokines, including those implicated in COPD.

METHODS

Here, we identify a novel protective role for TTP in CS-induced experimental COPD using mice, a genetically modified mouse strain in which endogenous TTP cannot be phosphorylated, rendering it constitutively active as an mRNA-destabilising factor. TTP wild-type ( ) and active C57BL/6J mice were exposed to CS for four days or eight weeks, and the impact on acute inflammatory responses or chronic features of COPD, respectively, was assessed.

RESULTS

After four days of CS exposure, mice had reduced numbers of airway neutrophils and lymphocytes and mRNA expression levels of cytokines compared to wild-type controls. After eight weeks, mice had reduced pulmonary inflammation, airway remodelling and emphysema-like alveolar enlargement, and lung function was improved. We then used pharmacological treatments (protein phosphatase 2A activator, AAL, and the proteasome inhibitor, bortezomib) to promote the activation and stabilisation of TTP and show that hallmark features of CS-induced experimental COPD were ameliorated.

CONCLUSION

Collectively, our study provides the first evidence for the therapeutic potential of inducing TTP as a treatment for COPD.