Theses and Dissertations

Date of Award

7-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Robert Gilkerson

Second Advisor

Megan Keniry

Third Advisor

Michael Persans

Abstract

Mitochondrial dynamics occurring under stress-induced conditions in SHSY5Y neuroblastoma cells provide insight into the OPA1-mediated mitochondrial fusion threshold in cells of varying energetic demands. Mitochondria are dynamic structures that are continuously balancing fusion and fission, depending on cellular needs. The ability to fuse and divide relies on the maintenance of the mitochondrial transmembrane potential. Stress-induced conditions in SHSY5Y cells were induced via utilization of carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophore that disrupts the transmembrane potential. OMA1 protein reacts to the loss of transmembrane potential and subsequently cleaves the fusion-active isoforms of OPA1, L-OPA1. This causes an accumulation of S-OPA1, the fusion inactive isoforms of OPA1, leading to fragmentation of the mitochondrial network due to a loss of fusion. Prior research has shown a transmembrane potential threshold of ~33% for OPA1-mediated fusion in 143B osteosarcoma cells. This study explores how the transmembrane potential threshold for OPA1-mediated fusion varies in more energetically demanding cell lines. Therefore, it is hypothesized that SHSY5Y cells will have a higher transmembrane potential threshold for OPA1-mediated fusion due to being neural-derived cells as opposed to the 143B osteosarcoma musculoskeletal-derived cells. Current studies in our laboratory indicate that OPA1-mediated fusion in SHSY5Y cells show a graded loss of L-OPA1 isoforms as CCCP concentration is increased, rather than a sharp threshold.

Comments

Copyright 2025 Jorge Alberto Elizondo. All Rights Reserved. https://proquest.com/docview/3254035361

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