ARG1 and respiratory system disorder: Our findings underscore the promise and effectiveness of the PEI–isoprenaline complex as a gene delivery system, with its demonstrated biocompatibility, transfection efficiency, and therapeutic outcomes, including arginase-1 gene knockdown and mitigation of airway inflammation and fibrosis, indicating it as a promising candidate for advancing asthma therapy and contributing to the understanding and control of airway remodeling in respiratory diseases.