B76-22 Decrease of Ferroptosis Inhibitor Nupr1 in At2 Cells Affects Mitochondrial Function and Metabolism in COPD

Abstract

Chronic Obstructive Pulmonary Disease (COPD) is characterized by chronic lung injury leading to loss of alveolar epithelial cells. Single cell RNA-sequencing (scRNA-seq) results of COPD patient’s lung samples showed reduced expression of NUPR1 in alveolar type 2 (AT2) cells. Further research showed that NUPR1 protects AT2 cells from cigarette smoke extract (CSE)-mediated ferroptosis. This led us to further research into how NUPR1 protects AT2 cells from ferroptosis. To assess the role of NUPR1, we knocked down NUPR1 in A549 and primary human bronchial epithelial cells and simultaneously treated the cells with cigarette smoke extract (CSE). We used metabolomic profiling, RNAseq, and measurements of mitochondrial content, mitochondrial membrane potential, lipid peroxidation, cell viability, and iron levels, to assess the effects of the knockdown in these cells. Moreover, we included mice with a genetic deletion of Nupr1-/-, and used transmission electron microscopy (TEM) to evaluate their mitochondrial morphology with age. NUPR1 inhibition impaired mitochondrial function and increased lipid peroxidation. Metabolomic profiling revealed metabolomic changes, including 58 metabolites increased and 52 metabolites decreased. Iron levels were elevated and TEM of NUPR1 siRNA treated A549 cells and Nupr1--/- mouse lungs showed more abundant and fragmented mitochondrial morphology. In conclusion our findings suggest that reduction of NUPR1 expression leads to dysregulation of ferroptosis resulting in AT2 dysfunction. Ultimately, leading to reduced mitochondrial function and changes in cellular metabolism, therefore decreased NUPR1 in AT2 cells may contribute to the pathogenesis of COPD.

This abstract is funded by: NIH