C98-05 Mitochondrial-Derived Microprotein Shmoose Is Reduced in COPD and Contributes to Dysfunctional Lung Repair

Rationale Chronic obstructive pulmonary disease (COPD) is characterized by accelerated lung aging and tissue destruction with impaired lung repair. As the 6th leading cause of death, COPD is characterized by chronic inflammation, abnormal epithelial repair and irreversible alveolar destruction called emphysema. COPD pathogenesis involves mitochondrial dysfunction that contributes to abnormal lung repair. Mitochondria are key metabolic organelles that mediate overall cellular responses to stress and are signaling hubs through mitochondrial-derived microproteins (MDPs), biologically active microproteins shorter than 100 amino acids that are encoded by the mtDNA. SHMOOSE is an MDP with protective roles and is depleted in neurological disease. However, the role of MDPs in lung disease and COPD remain understudied. We hypothesized that the MDP SHMOOSE is dysregulated in COPD and contributes to mechanisms of abnormal lung repair. Methods Using whole genome sequencing from the COPDGene cohort, we identified a genetic variant in the mitochondrial gene of SHMOOSE. We utilized novel bioinformatic discovery tools, mitochondria-wide association scans (MiWAS) to identify genetic variants in MDPs related to COPD. We evaluated SHMOOSE levels by inhouse ELISA in human plasma (NIH BioLINCC LTRC), lung tissue lysates and by immunofluorescent staining. We treated Beas-2b cells with SHMOOSE and evaluated protein kinase N1 (PKN1) and GSK3 by western blot, cell proliferation, and cellular metabolism by Seahorse Analysis. Human alveolar type 2 (AT2) cells were grown into 3D organoids and treated with SHMOOSE to evaluate reparative capacity. Results Within COPDGene whole genome sequencing data, we identified a genetic variant in the mitochondrial gene of SHMOOSE. Using plasma samples from the NIH BioLINCC repository, SHMOOSE was significantly reduced in plasma of subjects with COPD (GOLD stages 1-2 and 3-4) and positively correlated with lung function by FEV1 (Figure 1). SHMOOSE was reduced in AT2 cells in COPD lungs by IF staining. In human bronchial epithelial cells, Beas-2b, SHMOOSE increased cell proliferation, increased phosphorylation of PKN1 and reduced GSK3, and altered mitochondrial respiration. In human AT2 cell-derived organoids from healthy donor lungs (52yo male and 50yo female), SHMOOSE significantly increased the number of alveolar organoids. Conclusions We demonstrate that the MDP SHMOOSE is reduced in the plasma of patients with COPD and correlates with lung function decline. SHMOOSE treatments inhibit PKN1 and downstream GSK3 signaling to augment cellular proliferation and lung plasticity. These findings underscore an important role for MDPs in lung repair and COPD pathogenesis with future therapeutic potential.