Biophysical Society Conference | Estes Park 2023

Membrane Budding and Fusion

Poster Abstracts

30-POS Board 10 CARBONYLATION OF SECRETORY PROTEINS INDUCED BY OXIDATIVE STRESS COMPOUNDS IN INSULIN-SECRETING CELLS Emma Saunders 1 ; Isaiah Lowe 1 ; David Soto 1 ; Vrishank Bikkumalla 1 ; Nhi Y Tran 1 ; Colin T Shearn 2 ; Jefferson Knight 1 ; 1 University of Colorado Denver, Department of Chemistry, Denver, CO, USA 2 University of Colorado Anschutz Medical Campus, Department of Pediatrics, Aurora, CO, USA 4-Hydroxynonenal (4HNE) is a reactive lipid aldehyde and a major product of lipid peroxidation, produced through reactions between reactive oxygen species (ROS) and polyunsaturated fatty acids. Pancreatic β -cells are responsible for insulin secretion in the pancreas and are known to be especially susceptible to oxidative stress due to their lack of key antioxidant enzymes catalase and superoxide dismutase. ROS and 4HNE production increase during inflammation, and cytokine-induced inflammatory responses contribute to the dysfunction, de-differentiation, and eventual death of β -cells in type 1 diabetes. 4HNE and other lipid aldehydes covalently modify nucleophilic amino acid sidechains, an irreversible damage process termed protein carbonylation. We hypothesize that key β -cell proteins involved in exocytosis are susceptible to carbonylation by reactive lipid aldehydes, which arise from cytokine-induced inflammatory pathways. This study aims to observe the effects of these compounds on insulin secreting cells, including GRINCH cells, MIN6 cells, and mouse pancreatic islets. We are using mass spectrometry-based proteomic analysis and Western blotting to identify proteins in these cells that are modified by 4HNE or cytokine treatment. Preliminary gene ontology analysis suggests that epigenetic modification and membrane trafficking are two of the main pathways affected. 4HNE inhibits insulin secretion in GRINCH cells on the minutes timescale or faster, suggesting key proteins in the secretory pathway are targets of acute damage. Overall, our goal is to better understand of the effects of inflammatory oxidative stress on β -cell secretory function in early stages of diabetes development.

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