Lgr4 Expression in Osteoblastic Cells Is Suppressed by Hydrogen Peroxide Treatment

LGR4 is expressed in bone and has been shown to be involved in bone metabolism. Oxidative stress is one of the key issues in pathophysiology of osteoporosis. However, the link between Lgr4 and oxidative stress has not been known. Therefore, effects of hydrogen peroxide on Lgr4 expression in osteoblasts were examined. Hydrogen peroxide treatment suppressed the levels of Lgr4 mRNA expression in an osteoblastic cell line, MC3T3-E1. The suppressive effects were not obvious at 0.1mM, while 1mM hydrogen peroxide suppressed Lgr4 expression by more than 50%. Hydrogen peroxide treatment suppressed Lgr4 expression within 12h and this suppression lasted at least up to 48h. Hydrogen peroxide suppression of Lgr4 expression was still observed in the presence of a transcription inhibitor but was no longer observed in the presence of a protein synthesis inhibitor. Although Lgr4 expression in osteoblasts is enhanced by BMP2 treatment as reported before, hydrogen peroxide treatment suppressed Lgr4 even in the presence of BMP2. Finally, hydrogen peroxide suppressed Lgr4 expression in primary cultures of osteoblasts similarly to MC3T3-E1 cells. These date indicate that hydrogen peroxide suppresses Lgr4 expression in osteoblastic cells. J. Cell. Physiol. 232: 1761-1766, 2017. (c) 2016 Wiley Periodicals, Inc. Lgr4 has been known to be related to osteoporosis or osteopenia. However, the link between Lgr4 and osteoporosis is not known. As aging is linked to oxidative stress in many tissues, we examined the effects of hydrogen peroxide on the expression of Lgr4 in osteoblasts. We found that hydrogen peroxide treatment suppresses expression of Lgr4 in osteoblasts.