CPA3 and hyperinsulinemic hypoglycemia, familial, 4: To investigate whether MCs play a crucial role in elastase/LPS-induced COPD-like disease, Cpa3Cre/+ mice, which lack mature MCs due to the carboxypeptidase A3 (Cpa3)-dependent genotoxic overexpression of Cre recombinase (24), were used to model MC deficiency.