PROJECT SUMMARY The thesis of this R35 Program is that immune cell derived “pathogenic exosomes” are key players in chronic obstructive pulmonary disease (COPD) and that their role can be modeled in a smoking mouse model of exosome transfer to attain novel understanding of the disease which can in turn be applied to COPD. This R35 Program is at the cutting edge of innovation having discovered the existence of alpha-1 antitrypsin (α-1AT) resistant neutrophil elastase (NE)+ neutrophil (PMN)-derived exosomes in COPD patients. In doing so, the Program has challenged the concept that protease activity is solely solution phase and shown extracellular matrix (ECM) proteolytic activity is hugely enhanced by protease attachment to the extracellular vesicle (EV) surface. Consequently, we: i) describe what appears to be the first EV that can transfer a COPD-like phenotype from humans to mice; ii) elucidate a new mechanism by which proteases escape anti-protease inactivation, leading to ECM degradation and cell death via receptor-interacting protein kinase 3 (RIPK3); iii) describe a new model that transfers a COPD phenotype from cigarette smoke (CS) exposed mice to naïve mice via immune cell- derived exosomes; iv) use the mouse model to discover a new CS induced protective mechanism against exosomal damage as well as a mechanism for exosomal self-propagation; v) uncover new therapeutic targets for exosomal damage and; vi) translate the new findings to better understand disease in COPD patients and smokers. Another highly significant aspect of this research Program is training/mentoring. In the past ten years, which includes the PI's inaugural R35 grant, the PI has been or is currently mentor to two PhD students, five medical students, an MD/PhD student, six K awardees, four postdoctoral trainees, a pulmonary fellow, and a cardiology fellow. The PI currently mentors seven junior faculty members. Overall, our Program is both multidisciplinary – employing chemistry, biochemistry, molecular and cell biology, animal physiology, etc. – and translational in pairing basic scientists with physician scientists. Our team and trainees fulfill the NHLBI/NIH mission to have diversity by including African American, Latina, Asian, and Caucasian members. Our program fulfills all four goals of the NHLBI Strategic Vision by: a) elucidating a new exosomal aspect of human biology; b) reducing human disease by new therapeutic development against the exosomal pathway; c) developing a work force and an animal model exosome resource and; d) translating the exosome research to human disease.

PROJECT NARRATIVE This project describes a new extracellular entity, the pathogen exosome. In diseases such as COPD this type of exosome drives chronic inflammation, tissue damage, and cell death. A complete understanding of the pathogenic exosome may lead to new diagnostics and therapeutics for chronic inflammatory diseases such as COPD.