Activation of canonical Wnt/beta-catenin signaling inhibits H2O2-induced decreases in proliferation and differentiation of human periodontal ligament fibroblasts

作者：Kook Sung Ho; Lee Daewoo; Cho Eui Sic; Heo Jung Sun; Poudel Sher Bahadur; Ahn Yu Hyeon; Hwang Jae Won; Ji Hyeok; Kim Jong Ghee; Lee Jeong Chae^*

来源：Molecular and Cellular Biochemistry, 2016, 411(1-2): 83-94.

DOI：10.1007/s11010-015-2570-4

• Human periodontal ligament fibroblasts
• Hydrogen peroxide
• Wnt pathway
• Differentiation
• Nrf2

Human periodontal ligament fibroblasts (hPLFs) are exposed to oxidative stress during periodontal inflammation and dental treatments. It is hypothesized that hydrogen peroxide (H2O2)-mediated oxidative stress decreases survival and osteogenic differentiation of hPLFs, whereas these decreases are prevented by activation of the Wnt pathway. However, there has been a lack of reports that define the exact roles of canonical Wnt/beta-catenin signaling in H2O2-exposed hPLFs. Treatment with H2O2 reduced viability and proliferation in hPLFs in a dose- and time-dependent manner and led to mitochondria-mediated apoptosis. Pretreatment with lithium chloride (LiCl) or Wnt1 inhibited the oxidative damage that occurred in H2O2-exposed hPLFs. However, knockout of beta-catenin or treatment with DKK1 facilitated the H2O2-induced decreases in viability, mitochondrial membrane potential, and Bcl-2 induction. Osteoblastic differentiation of hPLFs was also inhibited by combined treatment with 100 mu M H2O2, as evidenced by the decreases in alkaline phosphatase (ALP) activity and mineralization. H2O2-mediated inhibition of osteoblast differentiation in hPLFs was significantly attenuated in the presence of 500 ng/ml Wnt1 or 20 mM LiCl. In particular, H2O2 stimulated the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) at protein and mRNA levels in hPLFs, whereas the induction was almost completely suppressed in the presence of Wnt1 or LiCl. Furthermore, siRNA-mediated silencing of Nrf2 blocked H2O2-induced decreases in ALP activity and mineralization of hPLFs with the concomitant restoration of runt-related transcription factor 2 and osteocalcin mRNA expression and ALP activity. Collectively, these results suggest that activation of the Wnt/beta-catenin pathway improves proliferation and mineralization in H2O2-exposed hPLFs by downregulating Nrf2.

• 出版日期2016-1