GSK3β is a checkpoint for TNF-α-mediated impaired osteogenic differentiation of mesenchymal stem cells in inflammatory microenvironments

• Published in: Biochimica et biophysica acta Vol. 1830; no. 11; pp. 5119 - 5129
• Main Authors: Kong, Xiangwei, Liu, Yan, Ye, Ruidong, Zhu, Bin, Zhu, Yuan, Liu, Xianghui, Hu, Chenghu, Luo, Hailang, Zhang, Yongjie, Ding, Yin, Jin, Yan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2013
• Subjects: Adenoviridae; Adult; beta Catenin - metabolism; bone formation; Cell Differentiation - physiology; Cell Nucleus - metabolism; Cells, Cultured; Core Binding Factor Alpha 1 Subunit - metabolism; enzyme-linked immunosorbent assay; gene overexpression; Glycogen Synthase Kinase 3 - metabolism; Glycogen Synthase Kinase 3 beta; Glycogen synthase kinase 3β; Humans; Inflammation - metabolism; Inflammation - pathology; interleukin-1beta; interleukin-6; interleukin-8; Interleukins - metabolism; ligaments; Lymphoid Enhancer-Binding Factor 1 - metabolism; Mesenchymal stem cell; Mesenchymal Stromal Cells - metabolism; Mesenchymal Stromal Cells - pathology; monocytes; Monocytes - metabolism; Monocytes - pathology; Osteogenesis - physiology; Osteogenic differentiation; patients; Periodontal Ligament - metabolism; Periodontal Ligament - pathology; periodontitis; Periodontitis - metabolism; Periodontitis - pathology; phosphorylation; Phosphorylation - physiology; secretion; small interfering RNA; Stem Cell Niche - physiology; stem cells; tau-protein kinase; transcription (genetics); tumor necrosis factor-alpha; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α; Western blotting; Young Adult; Mesenchymal stem cell; Tumor necrosis factor-α; Osteogenic differentiation; Glycogen synthase kinase 3β
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2013.07.027

The fate and differentiation of mesenchymal stem cells (MSCs) depend on various microenvironmental cues. In chronic inflammatory bone disease, bone regeneration is inhibited. The present study therefore sought to identify the underlying molecule mechanisms. We isolated periodontal ligament stem cells (PDLSCs), a new population of MSCs, from the periodontal ligament tissues of periodontitis patients and healthy controls (p-PDLSCs and h-PDLSCs). The secretion of inflammatory cytokines, like TNF-α, IL-1β, IL-6 and IL-8, after LPS stimulation was measured by ELISA. The expressions of p-GSK3β and GSK3β in two types of PDLSCs were detected by Western blot. TOPFlash was used to assay the Tcf/Lef transcriptional activity. Knockdown of GSK3β by siRNA and over-expression of GSK3β by adenoviruses were performed to confirm the role of GSK3β in the impaired osteogenic differentiation of PDLSCs under inflammatory microenvironment. We demonstrated that p-PDLSCs displayed impaired osteogenic capacity than h-PDLSCs. Upon inflammatory stimulation, monocytes, but not PDLSCs, released inflammatory cytokines among which TNF-α directly act on PDLSCs and suppressed their osteogenic differentiation. TNF-α induced the phosphorylation of GSK3β, the deactivated form of GSK3β, which increased nuclear β-catenin and Lef-1 accumulation, and eventually reduced the Runx2-associated osteogenesis in PDLSCs. Over-expression of GSK3β rescued osteogenesis in TNF-α-stimulated PDLSCs, whereas inactivation of GSK3β was sufficient to liberate the β-catenin/Lef-1/Runx2 pathway. GSK3β plays an obligatory role in the TNF-α-mediated inhibition of osteogenesis in MSCs. The strategy to target GSK3β may provide a potential approach to bone regeneration in inflammatory microenvironments. •p-PDLSCs have impaired osteogenic ability compared with h-PDLSCs.•TNF-α is the key perpetrator among cytokines inhibiting the osteogenesis of PDLSCs.•TNF-α induces hyper-phosphorylation of GSK3β in PDLSCs.•Over-expression of GSK3β rescues osteogenesis in TNF-α-stimulated PDLSCs.•Inhibition of GSK3β is sufficient to liberate the β-catenin/Lef-1/Runx2 pathway.