Investigating the fibrotic effects of oxidized linoleic acid metabolites
department or school: Science, Irving K. Barber Faculty of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Letef, Clara Anne
issued: 2024-04-29T19:21:07Z
issued: 2024
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: The North American diet is rich in omega-6 fatty acids, with linoleic acid (LA) being the most common. LA is blamed for heart muscle disease characterized by oxidative stress, fibrosis, and mitochondrial dysfunction. However, exact pathways of damage remain elusive. LA gets converted to oxidized linoleic acid metabolites (OXLAMs) by lipoxygenase (LOX). This thesis investigated how OXLAMs such as 13-hydroperoxyoctadecadienoic acid (13-HpODE), 13-hydroxyoctadecadienoic acid (13-HODE), 9-hydroperoxyoctadecadienoic acid (9-HpODE), and 9-hydroxyoctadecadenoic acid (9-HODE) impact mitochondrial redox status and fibrotic pathways using an in vitro model of NIH/3T3 fibroblasts. Cells were dosed with LA with or without 9c(i472) (an inhibitor of 15-LOX). Fibroblasts under LA showed decreased mitochondrial redox status with increased soluble nascent collagen as signs of stress. Using 9c(i472) restored mitochondrial redox potential and promoted deposited collagen instead. Inhibiting 13-HpODE production increased collagen III gene (the elastic subtype) and decreased collagen I gene representing the stiff collagen isoform. This indicates that LA’s bioconversion to 13-HpODE is critical for promoting ‘stiffness’ with LA treatment. To investigate the role of oxidative stress, H₂O₂ was added to fibroblasts treated with 9- or 13-HpODE. Although mitochondrial redox status dropped in both groups with H₂O₂, the drop was larger with 13-HpODE. This indicated a greater consumption of mitochondrial antioxidants by 13-HpODE than 9-HpODE. After its production, HpODEs is cleared to non-reactive HODEs using glutathione (GSH), as the co-factor. Supplementing fibroblasts with GSH could not reverse the drop in mitochondrial potential with H₂O₂ and HpODEs. However, adding GSH did improve the redox potential in LA treated cells. This indicates that LA through some unknown mechanism promotes greater utilization of GSH than its oxidized derivatives. Finally, gene expression of other mitochondrial antio…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/88090
note: INVESTIGATING THE FIBROTIC EFFECTS OF OXIDIZED LINOLEIC ACID METABOLITES by Clara Anne Letef B.Sc., The University of British Columbia, 2022 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Biochemistry and Molecular Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) April 2024 © Clara Anne Letef, 2024 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis entitled: Investigating the fibrotic effects of oxidized linoleic acid metabolites submitted by Clara Anne Letef in partial fulfillment of the requirements of the degree of Master of Science . Dr. Sanjoy Ghosh, Irving K. Barber Faculty of Science Supervisor Dr. Kirk Bergstrom, Irving K. Barber Faculty of Science Supervisory Committee Member Dr. Isaac Li, Irving K. Barber Faculty of Science Supervisory Committee Member Dr. Ismail Laher, Professor, The University of British Columbia (Vancouver) University Examiner iii Abstract The North American diet is rich in omega-6 fatty acids, with linoleic acid (LA) being the most common. LA is blamed for heart muscle disease characterized by oxidative stress, fibrosis, and mitochondrial dysfunction. However, exact pathways of damage remain elusive. LA gets converted to oxidized linoleic acid metabolites (OXLAMs) by lipoxygenase (LOX). This thesis investigated how OXLAMs such as 13-hydroperoxyoctadecadienoic acid (13-HpODE), 13-hydroxyoctadecadienoic acid (13-HODE), 9-hydroperoxyoctadecadienoic acid (9-HpODE), and 9-hydroxyoctadecadenoic acid (9-HODE) impact mitochondrial redox status and fibrotic pathways using an in vitro model of NIH/3T3 fibroblasts. Cells were dosed with LA with or without 9c(i472) (an inhibitor of 15-LOX). Fibroblasts under LA showed decreased mitochondrial redox status with increased soluble nascent collagen as signs of stress. Using 9c(i472) restored mitochondrial redox potential and promot…
has type: Thesis/Dissertation
date issued: 2024-05
is shown at: 10.14288/1.0442002
language: eng
degree discipline: Biochemistry and Molecular Biology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Ghosh, Sanjoy
type: Text
identifier URI: http://hdl.handle.net/2429/88090