Hypermethylation of Frizzled1 is associated with Wnt/β-catenin signaling inactivation in mesenchymal stem cells of patients with steroid-associated osteonecrosis

Abstract

The Wnt/β-catenin signaling pathway is associated with the pathogenesis of steroid-induced osteonecrosis. Our investigation studied whether aberrant CpG island hypermethylation of the FZD1 gene was present in patients with osteonecrosis of the femoral head (ONFH), which results in Wnt/β-catenin signaling inactivation and subsequent cell dysfunction. Bone marrow was collected from the proximal femurs of patients with steroid-associated ONFH ( n = 21) and patients with new femoral neck fractures ( n = 22), and then mesenchymal stem cells (MSCs) were isolated. We investigated cell viability, the transcription and translation levels of Wnt/β-catenin signaling-related genes, the extent of methylation at CpG islands of the FZD1 promoter, and the osteogenic and adipogenic differentiation abilities of MSCs from the control group and from the ONFH group treated with or without 5′-Aza-dC. According to the results, MSCs from the ONFH group showed a reduced proliferation ability, low transcription and translation levels of FZD1, inhibition of the Wnt/β-catenin signaling pathway, weakened osteogenesis and enhanced adipogenesis ability. Aberrant CpG island hypermethylation of FZD1 was observed in the ONFH group. Treatment with 5’-Aza-dC resulted in de novo FZD1 expression, reactivation of the Wnt/β-catenin signaling pathway and promotion of osteogenesis. Taken together, our study not only provides novel insights into the regulation of the Wnt/β-catenin signaling pathway in this disease but also reveals potential for the use of demethylating agents for the treatment of GC-associated ONFH.

CD41-deficient exosomes from non-traumatic femoral head necrosis tissues impair osteogenic differentiation and migration of mesenchymal stem cells

“…focusing on the balance of osteogenesis, bone resorption and angiogenesis [28][29][30][31] . Among these mechanisms, the influenced osteogenic differentiation, proliferation and migration of MSCs are considered as the top factors leading to ONFH 8,9 . Glucocorticoid (GC)-treated models were used to study the mechanism of ONFH in vivo and in vitro, due to the use of GC as the common etiology of this disease 32 .…”

“…MSCs with pluripotency of differentiation play a critical role in ONFH 7,8 . The impaired osteogenic differentiation and migration of MSCs is considered as the major factor leading to ONFH 9 . However, MSCs implantation remains a high rate of failure 10 .…”

Increased COUP-TFII Expression Mediates the Differentiation Imbalance of Bone Marrow-Derived Mesenchymal Stem Cells in Femoral Head Osteonecrosis

“…Many diseases, including osteoporosis and osteonecrosis, have been shown to be significantly associated with imbalances between osteogenic and adipogenic differentiation of BMSCs [44, 45]. Recent studies also revealed that ONFH is mainly caused by increased differentiation of BMSCs into adipocytes and decreased bone osteogenesis [46, 47]. This study showed increased adipogenesis and decreased osteogenesis in necrotic regions of the femoral head.…”

The Roles of Epigenetics Regulation in Bone Metabolism and Osteoporosis

“…Gene function in osteogenesis RUNX2 Low TF, promote the expression of target genes and osteogenic differentiation (Zhang R. P. et al, 2011;Wakitani et al, 2017) OSX Low TF, promote the expression of target genes and osteogenic differentiation (Zhang R. P. et al, 2011;Farshdousti Hagh et al, 2015) BMP2 Low Bone growth factor, promote osteogenic differentiation (Fu et al, 2013;Raje and Ashma, 2019) SOST High Glycoprotein, inhibit osteogenic differentiation (Reppe et al, 2015a;Cao et al, 2019) ALP Low Hydrolyze phosphate ester to provide necessary phosphoric acid for the deposition of hydroxyapatite, and at the same time hydrolyze pyrophosphate to remove its inhibitory effect on bone salt formation (Delgado-Calle et al, 2011;Yang and Duan, 2016;Licini et al, 2019) OCN Low Maintain normal bone mineralization (Villagra et al, 2002;Licini et al, 2019) Frizzled1 Low Activate the wnt pathway and promote osteogenic differentiation (Wu et al, 2019) RANKL High Stimulate osteoclast differentiation and promote bone resorption (Ghayor and Weber, 2016;Behera et al, 2018) OPG Low Inhibit osteoclast differentiation (Ghayor and Weber, 2016;Wang et al, 2018) LOX Low Promote osteogenic differentiation (Thaler et al, 2011) ESR1 Low Promote osteogenic differentiation (Penolazzi et al, 2004) DLX5 Low Promote osteogenic differentiation Li et al, 2009) Alu elements…”