Finally, given that PAI-1 has profibrotic effects [46] and is associated with airway fibrosis, and that small-airway remodeling is a key pathological feature of COPD [47], it would be preferable to validate these findings using a model that more accurately reflects the pathophysiology of human COPD in order to better evaluate the therapeutic potential of TM5441. The gene discussed is SERPINE1; the disease is chronic obstructive pulmonary disease.