Reciprocal Interferences of TNF-α and Wnt1/β-Catenin Signaling Axes Shift Bone Marrow-Derived Stem Cells Towards Osteoblast Lineage after Ethanol Exposure

Cellular Physiology and Biochemistry

关键词: Ethanol;    Multipotential mesenchymal stem cells (MSC);    Bone-marrow stem cells (BMSC);    Osteoblast;    Osteogenesis;    Adipogenisis;    TNF-α;    Wnt1;    β-catenin;    siRNA;   

DOI  :  10.1159/000354477

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background/Aims We have reported in a separate study that alcohol exposure triggers activation of the TNF-α signaling pathway leading to an adverse shift of multipotential mesenchymal stem cells in bone marrow (BMSCs) away from osteogenesis towards adipogenesis. However, inhibition of TNF-α signaling only yielded moderate inhibition of adipogenesis. Here we showed that in addition to promoting the TNF-α signaling, alcohol also suppressed the Wnt1/β-catenin signaling pathway. Methods We treated primary BMSCs from human subjects with alcohol for 24 days. We measured changes of genes related to endoplasmic reticulum (ER) stress, adipogenic markers and osteogenic markers using quantitative real-time RT-PCR and Western blot analysis. We performed Alizarin red staining for osteogenesis. We also conducted assays for osteogenic biomarkers alkaline phosphatase, collagen-I and osteocalcin. Results Wnt/β-catenin signaling was markedly activated in BMSCs treated with osteogenic inducers relative to the control cells, as indicated by the increased levels of nuclear β-catenin along with reduced levels of cytosolic β-catenin, as well as increased protein levels of Wnt1. Activation of Wnt/β-catenin signaling was significantly suppressed in BMSCs exposed to alcohol, which was reflected by downregulated expression of osteogenic marker genes Osf2/Cbfa1, osteopontin and osteocalcin, upregulated adipogenic marker PPARγ2 and aP2, and reduced number of calcifcation nodules. In contrast, activation of Wnt/β-catenin signaling by BIO favored osteogenesis even in the presence of alcohol. Simultaneous activation of Wnt1 by BIO and inhibition of TNF-α by 3,6'-dithiothalidomide produced synergetic suppression of ethanol-induced adipogenic lineage compared to interference with either of them alone. Conclusion This remarkable shift of BMSCs towards osteoblast lineage suggests the superiority of concordant and reciprocal interferences of the TNF-α and Wnt/β-catenin pathways for promoting osteogenesis.

【 授权许可】

CC BY-NC-ND