Document Type

Honors Thesis

Semester of Graduation

Spring 2026

Abstract

Tissue regeneration is marked by significant macrophage activity. Macrophages aid in signaling pathways for tissue growth and differentiation. Salamanders are the only limbed vertebrates capable of complete limb regeneration. However, Polypterus senegalus can fully regenerate its fins after injury. It has been determined that mTOR signaling by macrophages is active in early regeneration. In this project, we will test whether mTOR signaling is necessary for the recruitment of macrophages to regenerate fins in Polypterus senegalus. We began with immunofluorescence of liposomes in tissue sections to quantify macrophages recruited by mTOR signaling in fish treated with DMSO and RAPA. RAPA has been shown to inhibit mTOR signaling and alter macrophage marker expression in salamanders. The next part of the study was to find different macrophage markers using bioinformatics. Previously, single-nucleus RNA sequencing (RNA-seq) and TrailMaker were used to create a visual catalog of all genes expressed in different regenerative states. Analysis of highly expressed genes across all regenerative states found in macrophages was completed from volcano plots created by TrailMaker. Then, pathway analysis was used to confirm that the new macrophage markers are present in tissue regeneration. Pathway analysis was completed with WebGestalt. Finally, we suggest immunofluorescence with the identified markers to be used to quantify the recruited macrophages in different regenerative states. The same macrophage markers are found in humans. Therefore, this research can be used to aid in reducing scar tissue formation after wounds or surgeries.

Awardee Name

Icyss Sargeant

Academic Major

Biochemistry

Project Mentor

Igor Schneider

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