Polyphenol-derived Hippuric acid and 3-(3-hydroxyphenyl) Propionic acid demethylates DNA to prevent sex steroid deficiency-induced bone loss in mice

Authors: CAVINESS, PERRY - Arkansas Children'S Nutrition Research Center (ACNC); LAZARENKO, OXANA - Arkansas Children'S Nutrition Research Center (ACNC); BLACKBURN, MICHAEL - Arkansas Children'S Nutrition Research Center (ACNC); CHEN, JIN-RAN - Arkansas Children'S Nutrition Research Center (ACNC)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: While Osteoporosis is primarily thought of as a disease that affects older populations it can affect juvenile populations as well. Currently Bisphosphonates such as Zoledronic acid (ZA), which work by inducing apoptosis in osteoclastic cells, are the most commonly prescribed treatments for osteoporosis. However, prolonged Bisphosphonate use comes with side effects such as fever and flu like symptoms, hypocalcemia, joint pain, gastro intestinal distress and osteonecrosis of the jaw. Due to these side effects, Bisphosphonates are not FDA approved younger patients. These adverse side effects highlight the need for alternative treatments for osteoporosis. Our research group has studied the effects of blueberry metabolites Hippuric Acid (HA) and 3-(3-hydroxyphenyl) propionic acid (3-3-PPA) on promoting bone growth through the upregulation of osteoblast differentiation and the downregulation of osteoclast differentiation. Previous work has identified the lowered expression of g-protein coupled receptor GPR109A as a key component of HA/3-3-PPA treatment. The downstream biochemical response from the downregulation of GPR109A is currently unknown. In this study, we sought to further define the pathways responsible for osteoclastogenesis that HA and 3-3-PPA inhibit. We have shown that female mice subject to ovariectomy were able to regain bone density comparable to Zoledronic acid treatment when treated with either HA or 3-3-PPA. While bone density appears to be equivalent for HA/3-3-PPA treated mice and Zoledronic acid mice only treatment with Zoledronic acid closed the tibia growth plate. By using an ELISA kit, it was determined that DNA methylation levels were lowered in genomic DNA isolated from mice pre-osteoclast cells and from L4 vertebrae. qPCR and western blot analysis show that HA and 3-3-PPA cause an increase in the expression of osteoclastic suppressor genes Irf8 and MafB. A significant negative correlation was found to exist in mice treated with HA or 3-3-PPA between genomic DNA methylation and Irf8 expression as well as genomic DNA methylation and percent bone volume. In turn a positive correlation was seen between Irf8 expression and percent bone volume. Our study provides strong evidence that HA and 3-3-PPA work to increase bone density by demethylating Irf8 leading to its upregulation. Future work will focus on the mechanism behind HA/3-3-PPA lowered DNA methylation or if HA/3-3-PPA may cause other epigenetic modifications in bone.