2026-05-19T20:12:50Zhttps://keep.lib.asu.edu/oai/request

oai:keep.lib.asu.edu:node-2005702025-05-23T23:39:08Zoai_pmh:alloai_pmh:repo_items

200570 https://hdl.handle.net/2286/R.2.N.200570 http://rightsstatements.org/vocab/InC/1.0/ http://creativecommons.org/licenses/by-nc-sa/4.0 2025-05 40 pages Livingston, Ashley Jurutka, Peter Wagner, Carl Barrett, The Honors College College of Health Solutions Periodontal disease, characterized by chronic inflammation of the gingival tissues, shares key features with oxidative stress-related disorders. Oxidative stress involves the overproduction of reactive oxygen species (ROS), often generated by activated polymorphonuclear leukocytes during inflammatory responses. A critical cellular defense mechanism against oxidative damage involves the transcription factor Nuclear Factor E2–related factor 2 (Nrf2). Under stress conditions, Nrf2 is released from its cytoplasmic inhibitor Keap1, translocates to the nucleus, and binds to Maf proteins. This complex activates the antioxidant response element (ARE), a regulatory DNA sequence located in the promoter region of several detoxifying and antioxidant genes, including heme oxygenase-1 (HO-1). This study investigates the potential of several dietary and pharmacological compounds to synergistically enhance Nrf2 activation and mitigate oxidative stress, with a particular focus on applications for oral health. Nutritional interventions are known to play a role in modulating antioxidant responses, and specific compounds such as vitamin D (1,25D), urolithin A, resveratrol, bexarotene, and Analog 55 (a rexinoid targeting retinoid X receptors) were selected for evaluation. An ARE-luciferase reporter assay was conducted in HEK293 cells, which express endogenous Nrf2, to assess compound efficacy. Urolithin A at 20 µM and resveratrol at 33 µM were found to significantly activate Nrf2. These findings prompted further exploration of potential synergy with vitamin D. While 20 µM urolithin A combined with 10 nM vitamin D showed no additive effect, a lower concentration (4 µM urolithin A with 10 nM vitamin D) resulted in enhanced Nrf2 activation. A similar pattern was observed with resveratrol: 6.6 µM resveratrol combined with 10 nM vitamin D produced a stronger synergistic effect than 33 µM resveratrol with the same vitamin D dose. To assess potential inhibitory interactions, a combination of 33 µM resveratrol + 10 nM vitamin D + 100 nM Analog 55 was tested, revealing suppression of Nrf2 activity. Because 10 nM vitamin D significantly enhanced the effects of 6.6 µM resveratrol, a dose-response test using vitamin D concentrations of 1 nM, 10 nM, and 25 nM in combination with 6.6 µM resveratrol was performed. Higher concentrations of vitamin D (10 nM and 25 nM) showed stronger synergy with resveratrol than either 1 nM vitamin D or resveratrol alone. To determine if these treatments led to downstream activation of Nrf2 target genes, qPCR assays were used to quantify HO-1 expression in HEK293 cells. Treatment groups included ethanol (control), urolithin A (20 µM), urolithin A + vitamin D (25 nM), resveratrol (6.6 µM), resveratrol + vitamin D (25 nM), and resveratrol + Analog 55 (100 nM). Both urolithin A and resveratrol individually upregulated HO-1 expression. However, urolithin A combined with vitamin D did not further enhance HO-1 expression relative to urolithin A alone. In contrast, resveratrol combined with vitamin D showed increased HO-1 expression compared to resveratrol alone, supporting a synergistic effect. Conversely, co-treatment with resveratrol and Analog 55 resulted in reduced HO-1 expression, confirming an inhibitory effect. These findings offer valuable insight into the modulation of the Nrf2/HO-1 pathway by nutritional compounds and support the development of new strategies to combat oxidative stress and inflammation associated with periodontal disease and to maintain optimal dental health. Nrf-2 HO-1 Rexinoid Resveratrol Urolithin A Vitamin D Periodontal Disease Oral Health The Effects of Cellular Anti-Oxidation Pathways on Oral Health