Anti-oxidative and anti-inflammatory effects of the phosphodiesterase 3/4 inhibitor ensifentrine

Ensifentr ine is a dual PDE3/4 inhibitor that improves lung function and symptoms in COPD patients. Ensifentrine has anti-inflammatory effects, but these have not been studied in cells from COPD patients. Oxidative stress is increased in the lungs of COPD patients, but the potential for ensifentrine to modulate oxidative stress induced apoptosis has not been investigated. We investigated the effects of ensifentrine on inflammation and oxidative stress in cell models relevant to COPD. Peripheral blood mononuclear cells (PBMCs) from COPD patients and healthy controls and human bronchial epithelial cells were treated with ensifentrine or a PDE4 inhibitor (roflumilast or GSK256066) or dexamethasone prior to exposure to lipopolysaccharide or T-cell receptor activation, with measurement of supernatant levels of TNFα and IFNγ, respectively. H₂O₂ induced oxidative stress was also investigated with measurements of caspase 3/7 activity, apoptosis associated gene expression, apoptosis and cell viability. Ensifentrine decreased production of TNFα and IFNγ in PBMCs from COPD patients and controls. IC₅₀ values for ensifentrine were greater than other compounds, while maximal inhibition was comparable at high concentrations. Ensifentrine reversed H₂O₂ induced caspase activity, alteration of apoptosis genes, apoptosis and cell death in both cell types, while PDE4 inhibitors had limited effects. These anti-apoptosis effects were dependent on PDE3-PKG-cGMP signalling. We report a novel mechanism of action for ensifentrine, reducing effects of oxidative stress through a PDE3 dependent mechanism. The anti-inflammatory effects of ensifentrine were lower compared to the PDE4 inhibitors tested.