Honors Program

Honors in Health Sciences: Microbiology

Date of Award

5-2022

Thesis Professor(s)

Matthew P. Keasey

Thesis Professor Department

Biomedical Sciences

Thesis Reader(s)

Sean J. Fox Cuihong Jia

Abstract

Brain calcification is a common occurrence in the aging process, with >20% of individuals over the age of 65 showing hardened plaques in the basal ganglia. Loss of the vitamin D receptor (VDR) in transgenic mice leads to formation of calcified plaques in the basal ganglia and thalamus within the mice. Vitamin D signals through two known vitamin D responsive proteins, protein disulfide isomerase A3 (PDIA3) and VDR. In vitro, vitamin D has been demonstrated to suppress calcification in osteoblast-like cells. Here, we aim to elucidate which of either PDIA3 or VDR transduce vitamin D mediated suppression of calcification in vitro. PDIA3 or VDR were selectively knocked out in human osteosarcoma (SaOs) cells using CRISPR-Cas9 technology to generate PDIA3 KO or VDR KO cells. Knockout for PDIA3 or VDR was confirmed by RT-qPCR assay or western blot analysis. The calcification of SaOs-2 cells was induced with treatment of β-glycerophosphate along with ascorbic acid allowing for determination of whether loss of PDIA3 or VDR would lead to altered calcium deposition. Cells null for PDIA3 but not VDR grew at a significantly slower rate than wild-type (WT) cells. Intriguingly, PDIA3 and VDR KO cells displayed significantly more calcification relative to WT control cells. Calcitriol or the synthetic analogue EB1089 suppressed calcification in vitro in WT and PDIA3 KO but not VDR KO cells as measured by alizarin red staining. These data suggest VDR is critical for mediating vitamin D’s inhibition of calcification in vitro, and that PDIA3 has a role in suppressing calcification. This study provides novel insights into vitamin D signaling and provides a foundation for further study and understanding of vitamin D related pathologies.

Publisher

East Tennessee State University

Document Type

Honors Thesis - Withheld

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Copyright

Copyright by the authors.

Available for download on Thursday, April 20, 2023

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