Nutrition and Health Sciences, Department of
Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research
First Advisor
Tomasz K. Bednarski
Committee Members
Edward Deehan, Jaekwon Lee, Ivan Vechetti
Date of this Version
Fall 12-1-2025
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Nutrition and Health Sciences
Under the supervision of Professor Tomasz K. Bednarski
Lincoln, Nebraska, November 2025
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by excessive lipid accumulation in hepatocytes and the development of lipotoxic stress that disrupts cellular homeostasis. Peroxisomal lipid metabolism plays an important role in maintaining acyl-CoA balance during fatty acid overload, yet the contribution of peroxisomal acyl-CoA thioesterases to early lipotoxic responses remains insufficiently understood. The aim of this study was to investigate the functional involvement of the peroxisomal enzymes acyl-CoA thioesterase 4 (ACOT4) and acyl-CoA thioesterase 8 (ACOT8) in hepatocyte lipid handling under acute lipotoxic conditions. An in vitro model of steatosis was established in AML12 cells through exposure to a mixture of palmitate and oleate (1:2). Lipid accumulation, metabolic stress markers, and gene expression profiles were assessed following individual silencing of Acot4 or Acot8. Fatty acids treatment induced steatosis and increased the expression of Acot4 and Acot8, alongside genes associated with lipid storage and endoplasmic reticulum (ER) stress. Silencing of either Acot4 or Acot8 reduced intracellular lipid accumulation and attenuated stress-related gene expression, indicating that the upregulation of these enzymes during lipid overload may represent a maladaptive response that promotes lipotoxicity rather than preventing it. These findings suggest that peroxisomal acyl-CoA metabolism contributes to early lipotoxic stress and highlights ACOT4 and ACOT8 as potential druggable nodes to mitigate hepatocellular dysfunction during the onset of MASLD.
Advisor: Tomasz K. Bednarski
Comments
Copyright 2025, Sylwia Miekus. Used by permission