MUC5AC and chronic obstructive pulmonary disease: While in the cluster dominated by CF an upregulation of adaptive immune system and a downregulatiorn of mucin glycosylation prevailed, in the cluster dominated by COPD exhibited a more heterogeneous response, characterized by a reduction in Signal Recognition Particle (SRP)-dependent protein targeting to the membrane and a trend towards a decrease in the matrisome (Fig. 5B).