Investigating mitochondria alterations in esophageal pathologies

Esophageal squamous epithelium possesses a defined proliferation-differentiation gradient essential for barrier function, the primary defense against luminal contents such as food allergens and carcinogens. This barrier is perturbed in esophageal diseases, including eosinophilic esophagitis (EoE), an emerging food allergy and immune-mediated inflammatory disorder, and esophageal squamous cell carcinoma (ESCC), an aggressive malignancy associated with poor patient outcomes. Roles for esophageal epithelial cells in the molecular pathogenesis of both EoE and ESCC states are currently emerging and a deeper understanding of these roles may unveil novel approaches for diagnosis, monitoring, and therapy of these widely prevalent esophageal diseases. Mitochondria are multifaceted organelles that regulate diverse cellular processes beyond energy production in both benign and malignant pathologies. Recently, metabolic and mitochondrial dysfunction have been implicated in EoE pathogenesis. However, there is a need to define the influence of EoE-associated inflammatory cues upon mitochondrial biology, mechanisms mediating these effects and the clinical significance of mitochondrial alterations in EoE. We hypothesize that altered mitochondrial biology contributes to EoE pathogenesis and promote inflammatory signaling in esophageal epithelial cells. To investigate the role of mitochondria in esophageal epithelium under EoE conditions, we quantified mitochondrial abundance in human biopsies, MC903/Ovalbumin-induced murine EoE, and assessed mitochondrial function and dynamics in human esophageal keratinocytes stimulated with EoE-relevant cytokines. We report evidence of increased mitochondria in esophageal mucosa of EoE patients and mice with EoE-like inflammation. Interleukin-13 (IL-13), a key EoE-associated cytokine, was found to induce mitochondrial accumulation in esophageal keratinocytes in vitro and this response was associated with increased expression of mediators of mitochondrial biogenesis, fusion, and mitophagy. Additionally, IL-13 suppressed mitochondrial respiration and ATP production, without impacting mitochondrial integrity or cell viability. To assess the clinical relevance of mitochondria in EoE, we evaluated mitochondrial DNA (mtDNA) copy number from culture media and circulating nucleic acids from human serum samples. Active EoE patients exhibited elevated serum mtDNA levels and upregulation of mediators of mtDNA-associated inflammatory signaling. Furthermore, increased mitochondrial mass and accumulation of extracellular mtDNA in IL-13-treated esophageal keratinocytes were dependent on JAK/STAT signaling. Taken together, these studies provide evidence of IL-13 as a mediator of increased mitochondrial mass in EoE through JAK/STAT signaling. We further demonstrate that IL-13 promotes accumulation of extracellular mtDNA and that circulating mtDNA is elevated in EoE patients. Given our findings that mitochondrial biology is altered in esophageal epithelial cells in response to inflammatory cues in EoE the well-established role of mitochondrial and metabolic reprogramming in cancer, we next sought to examine whether mitochondrial functions are altered in esophageal cancer cells responding to the experimental therapeutic diclofenac. Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive forms of human malignancy and often displays limited therapeutic response. Previous studies found increased COX-2 expression in ESCC lesions. Non-steroidal anti-inflammatory drugs (NSAIDs), inhibit cyclooxygenase (COX) enzymes and have been shown to have anticancer properties. However, the mechanisms through which NSAIDs influence ESCC cell survival were unexplored. Given this, we conducted a preclinical study aimed at examining the efficacy of the NSAID, diclofenac (DCF), as a novel therapeutic agent in ESCC. In addition to robustly diminishing the viability of multiple ESCC cell lines, including TE11, KYSE150 and KYSE 410, without impacting normal esophageal epithelial cells, DCF also increased apoptosis and altered cell cycle profiles in ESCC cell lines TE11 and KYSE150. Further, RNA-sequencing of DCF-treated TE11 cells identified differentially expressed genes while Ingenuity Pathway Analysis (IPA) predicted alterations in pathways associated with cellular metabolism. Proteins associated with glycolysis were downregulated in DCF-treated TE11 and KYSE150 cell lines. Moreover, mitochondrial depolarization and superoxide production was induced by DCF in TE11 and KYSE150 cell lines. Taken together, the studies described in this dissertation identify roles for esophageal epithelial mitochondrial in both EoE and ESCC, two widely prevalent esophageal diseases. We (1) identified IL-13 as a mediator of mitochondrial alterations and mtDNA-associated inflammatory signaling in EoE; (2) explored the clinical relevance of mitochondria in EoE; and (3) defined the molecular mechanisms through which NSAID, diclofenac, induces cytotoxicity in ESCC cells.

Grantor dc:publisher

Temple University. Libraries

Year dc:date.issued

2026

Author dc:creator

• Jackson, Jazmyne Lashelle

Advisor dc:contributor.advisor

• Whelan, Kelly A.

Committee members dc:contributor.committeemember

• Shore, Scott K.
• Fossati, Silvia
• Cañadas, Israel
• Souza, Rhonda

• Cellular biology
• Molecular biology
• Eosinophilic esophagitis
• Esophageal diseases
• Esophageal squamous cell carcinoma
• Mitochondria
• Biomedical sciences

Statement dc:rights

• IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available.

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

eng

Repository record dc:identifier.uri

https://scholarshare.temple.edu/handle/20.500.12613/12253

OAI identifier oai:identifier

oai:scholarshare.temple.edu:20.500.12613/12253