Degree

Honors Baccalaureate

Department

Biology

Document Type

Thesis

Abstract

Tanycytes are radial glial-like astrocytes whose cell bodies line the third ventricle (3V) with long processes extending into the hypothalamic parenchyma. In adult mice, tanycytes retain stem cell properties, with their daughter cells integrating into the median eminence or mediobasal hypothalamus. Tanycytes are implicated in glucose homeostasis and appetitive behaviors not only via the maintenance of hypothalamic cell populations, but also by their glucose, fatty acid, and hormone-sensing capabilities. Fibroblast Growth Factor Receptor 1 (FGFR1) is a tyrosine kinase receptor expressed in neural progenitor cells, including tanycytes, where it induces cell proliferation and therefore plays an integral role in neural stem cell (NSC) population maintenance. Despite their unique role in metabolism, the physiological role of tanycyte neurogenesis is not well understood. One factor that alters NSC dynamics is a high-fat diet (HFD): it has been observed to impair neurogenesis in the dentate gyrus (DG) and lateral ventricles while inducing tanycyte subpopulation-specific proliferation. This thesis examines the effect of a high-fat diet and Fgfr1 inactivation on neural progenitor cell proliferation and NSC reserve among the three neurogenic niches in the brain: the hypothalamus, the DG, and the lateral ventricles. Fgfr1 conditional knockout (cKO) mice and control mice were placed on either a HFD or normal-fat diet for 60 days, and immunohistochemistry was performed to characterize cell proliferation (PCNA) and NSC reserve (SOX2). While no significant proliferation differences were found, there was a significant reduction in DG NSC reserve of HFD-treated females, with the difference being more pronounced in cKO females. This indicates that females may be more vulnerable to reduction of DG NSC reserve when on a HFD, and that FGFR1 dysfunction can exacerbate these dietary effects.

Date

Spring 2026

First Committee Chair

Karen M. Smith

First Committee Member

Erika Caramillo-Hatch

Second Committee Member

Mirna Marinic

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