Sponsor
Jason E Podrabsky
First Advisor
Jason E Podrabsky
Date of Award
8-1-2025
Document Type
Thesis
Degree Name
Bachelor of Science (B.S.) in Biology and University Honors
Department
Biology
Language
English
Subjects
GATA4, NKX2-5, Austrofundulus limnaeus, cardiac regeneration, ischemia-reperfusion injury
Abstract
The annual killifish Austrofundulus limnaeus possesses exceptional tolerance to prolonged anoxia, offering a unique vertebrate model for investigating cardiac resilience and survival under metabolic stress. This study tested whether inhibition of the GATA4–NKX2-5 transcriptional axis with the small molecule 3i-1000 enhances post-anoxic survival. WS40 embryos were exposed to 50 µM 3i-1000 during anoxia and early aerobic recovery. Outcomes were assessed across two independent experimental cohorts. Treated embryos exhibited higher survivability during reoxygenation: in the October cohort, survival increased from 76.0% in vehicle controls (n = 25) to 91.7% in treated embryos (n = 24); in the November cohort, survival improved from 65.9% (n = 56) to 79.2% (n = 52). No significant differences in heart rate were detected between groups, though violin plot distributions did indicate heterogeneity in physiological responses. Post-anoxic survival can be parsed into three distinct cohorts—hatching, diapause, and arrested—across both experimental and control groups. No treatment-induced differences were observed in developmental timing. Together, these findings support the hypothesis that pharmacological disruption of GATA4–NKX2-5-promoted gene transcription enhances survivability under metabolic stress, though current endpoints remain coarse. Future work should incorporate higher-resolution metrics such as electrocardiography, TUNEL staining, and transcriptomic profiling to more precisely characterize potential cardioprotective mechanisms and improve translational relevance to mammalian systems. This work provides new insight into how modulating conserved transcriptional pathways intersects with natural survival strategies and lays the groundwork for future exploration of cardiac regeneration in anoxia-tolerant vertebrates.
Recommended Citation
Kime, Connor Taylor, "Small Molecule Inhibitor 3i-1000 Dosed During Bouts of Anoxia Increases Survivability of Austrofundulus limnaeus embryos" (2025). University Honors Theses. Paper 1760.