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Small molecule-based disruption of the Axin/β-catenin protein complex regulates mesenchymal stem cell differentiation.

ABSTRACT: The Wnt/β-catenin pathway plays important roles in the differentiation of multiple cell types, including mesenchymal stem cells. Using a cell-based chemical screening assay with a synthetic chemical library of 270 000 compounds, we identified the compound SKL2001 as a novel agonist of the Wnt/β-catenin pathway and uncovered its molecular mechanism of action. SKL2001 upregulated β-catenin responsive transcription by increasing the intracellular β-catenin protein level and inhibited the phosphorylation of β-catenin at residues Ser33/37/Thr41 and Ser45, which would mark it for proteasomal degradation, without affecting CK1 and GSK-3β enzyme activities. Biochemical analysis revealed that SKL2001 disrupted the Axin/β-catenin interaction, which is a critical step for CK1- and GSK-3β-mediated phosphorylation of β-catenin at Ser33/37/Thr41 and Ser45. The treatment of mesenchymal stem cells with SKL2001 promoted osteoblastogenesis and suppressed adipocyte differentiation, both of which were accompanied by the activation of Wnt/β-catenin pathway. Our findings provide a new strategy to regulate mesenchymal stem cell differentiation by modulation of the Wnt/β-catenin pathway.

SUBMITTER: Gwak J

PROVIDER: S-EPMC3351914 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Crystal structure of a beta-catenin/axin complex suggests a mechanism for the beta-catenin destruction complex.

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| S-EPMC3529405 | biostudies-literature

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Project description:The Wnt signal transduction pathway is dysregulated in many highly prevalent diseases, including cancer. Unfortunately, drug discovery efforts have been hampered by the paucity of targets and drug-like lead molecules amenable to drug discovery. Recently, we reported the FDA-approved anthelmintic drug Niclosamide inhibits Wnt/β-catenin signaling by a unique mechanism, though the target responsible remains unknown. We interrogated the mechanism and structure-activity relationships to understand drivers of potency and to assist target identification efforts. We found inhibition of Wnt signaling by Niclosamide appears unique among the structurally-related anthelmintic agents tested and found the potency and functional response was dependent on small changes in the chemical structure of Niclosamide. Overall, these findings support efforts to identify the target of Niclosamide inhibition of Wnt/β-catenin signaling and the discovery of potent and selective modulators to treat human disease.

| S-EPMC3660039 | biostudies-literature

Targeted disruption of the BCL9/beta-catenin complex in cancer

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2012-08-23 | E-GEOD-33143 | biostudies-arrayexpress

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| S-EPMC6522533 | biostudies-literature

Wnt/β-catenin signaling regulates the proliferation and differentiation of mesenchymal progenitor cells through the p53 pathway.

Project description:ObjectiveMesenchymal progenitor cells (MPCs) are found in articular cartilage from normal controls and patients with osteoarthritis (OA). Nevertheless, the molecular mechanisms of the proliferation and differentiation of these cells remain unclear. In this study, we aimed to determine the involvement of Wnt/β-catenin signaling in regulating the proliferation and differentiation of MPCs.MethodsMPCs were isolated from the articular cartilage of normal and OA patients. Cells were sorted by immunomagnetic cell separation. Cell proliferation capacity was evaluated using the MTT assay. Toluidine blue staining and immunostaining with anti-collagen II or anti-aggrecan antibodies were used to determine the chondrogenic differentiation capabilities of MPCs. The mRNA and protein expression of target genes were examined by quantitative real-time polymerase chain reaction and Western blotting, respectively. Knock-down of p53 expression was achieved with RNA interference.ResultsMost cells isolated from the normal and OA patients were CD105(+) and CD166(+) positive (Normal subjects: CD105(+)/CD166(+), 94.6% ± 1.1%; OA: CD105(+)/CD166(+), 93.5% ± 1.1%). MPCs derived from OA subjects exhibited decreased differentiation capabilities and enhanced Wnt/β-catenin activity. Inhibition of Wnt/β-catenin signaling promoted proliferation and differentiation, whereas activation of this pathway by treatment with rWnt3a protein decreased the proliferation and differentiation of normal MPCs. Additionally, Wnt/β-catenin signaling positively regulated p53 expression, and silencing of p53 increased proliferation and differentiation of MPCs.ConclusionsWnt/β-catenin regulated the proliferation and differentiation of MPCs through the p53 pathway.

| S-EPMC4018322 | biostudies-literature

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