AbstractThe regulatory network between signaling pathways and transcription factors (TFs) is crucial for the maintenance of pluripotent stem cells. However, little is known about how the key TF OCT4 coordinates signaling pathways to regulate self‐renewal and lineage differentiation of porcine pluripotent stem cells (pPSCs). Here, we explored the function of OCT4 in pPSCs by transcriptome and chromatin accessibility analysis. The TFs motif enrichment analysis revealed that, following OCT4 knockdown, the regions of increased chromatin accessibility were enriched with EOMES, GATA6, and FOXA1, indicating that pPSCs differentiated toward the mesoendoderm (ME) lineage. Besides, pPSCs rapidly differentiated into ME when the WNT/β‐catenin inhibitor XAV939 was removed. However, the ME differentiation of pPSCs caused by OCT4 knockdown did not rely on the activation of WNT/β‐catenin signaling because the target gene of WNT/β‐catenin signaling, AXIN2 was not upregulated after OCT4 knockdown, despite significant upregulation of WLS and some WNT ligands. Importantly, OCT4 is directly bound to the promoter and enhancers of EOMES and repressed its transcription. Overexpression of EOMES was sufficient to induce ME differentiation in the presence of XAV939. These results demonstrate that OCT4 can regulate WNT/β‐catenin signaling and prevent ME differentiation of pPSCs by repressing EOMES transcription.

2023-07-01·The Ocular Surface

Wnt/β-catenin signaling controls mouse eyelid growth by mediating epithelial-mesenchymal interactions

Article

作者: Ma, Gang ; Senoo, Makoto ; Millar, Sarah E ; Zhu, Xuming

PURPOSETo investigate the role of Wnt/β-catenin signaling in mouse eyelid development.METHODSWnt/β-catenin signaling was disrupted by deleting supraorbital mesenchymal β-catenin or epithelial Wls. p63 was removed to determine whether the expression of Wnts is affected. The eyelid morphology was examined at different stages. Proliferation, apoptosis, and expression of Wnt ligands and their target genes were analyzed via immunofluorescence staining, TUNEL assay, and in situ hybridization.RESULTSDeletion of β-catenin in supraorbital mesenchyme abolishes eyelid growth by causing decreased proliferation in supraorbital epithelium and underlying mesenchyme. Inhibition of Wnt secretion by deleting Wls in supraorbital epithelium results in failure of eyelid development, similar to the effects of deleting mesenchymal β-catenin. Knockout of p63 results in formation of hypoplastic eyelids and reduced expression of several Wnt ligands in eyelid epithelium.CONCLUSIONSEpithelial Wnt ligands activate mesenchymal Wnt/β-catenin signaling to control eyelid growth and their expression is partially regulated by p63.

2023-06-01·Advanced Science

Wnt3a‐Loaded Extracellular Vesicles Promote Alveolar Epithelial Regeneration after Lung Injury

Article

作者: Sun, Yongping ; Wang, Enyu ; Xie, An ; Cheng, Linzhao ; Gao, Lei ; Ma, Ding ; Zhang, Xinye ; Liu, Senquan

AbstractCompromised regeneration resulting from the deactivation of Wnt/β‐catenin signaling contributes to the progression of chronic obstructive pulmonary disease (COPD) with limited therapeutic options. Extracellular cytokine‐induced Wnt‐based signaling provides an alternative option for COPD treatment. However, the hydrophobic nature of Wnt proteins limits their purification and use. This study devises a strategy to deliver the membrane‐bound wingless‐type MMTV integration site family, member 3A (Wnt3a) over a long distance by anchoring it to the surface of extracellular vesicles (EVs). The newly engineered Wnt3aWG EVs are generated by co‐expressing Wnt3a with two genes encoding the membrane protein, WLS, and an engineered glypican, GPC6ΔGPI‐C1C2. The bioactivity of Wnt3aWG EVs is validated using a TOPFlash assay and a mesoderm differentiation model of human pluripotent stem cells. Wnt3aWG EVs activate Wnt signaling and promote cell growth following human alveolar epithelial cell injury. In an elastase‐induced emphysema model, impaired pulmonary function and enlarged airspace are greatly restored by the intravenous delivery of Wnt3aWG EVs. Single‐cell RNA sequencing–based analyses further highlight that Wnt3aWG EV‐activated regenerative programs are responsible for its beneficial effects. These findings suggest that EV‐based Wnt3a delivery represents a novel therapeutic strategy for lung repair and regeneration after injury.