Transcriptional changes in Wnt antagonism- and TGFβ agonism-induced MSC chondrogenesis.
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ABSTRACT: Wnt/β-catenin signaling is important in skeletal related-tissue development. We have found that Wnt/β-catenin antagonist XAV could replace traditionally used TGFβ3 as chondrogenic inducer. Here we applied gene expression array to characterize transcriptomic changes between XAV- and TGFβ-induced chondrogenic differentiation in human bone marrow (BM) and induced pluripotent stem cell (iPSC) derived MSCs.
Project description:Long-term dynamic compression enhanced the mechanical properties of MSC-seeded constructs only when loading was initiated after 21 days of chondrogenic differentiation. This study examined the molecular differences of chondrogenic MSCs compared to undifferentiated MSCs (TGF-beta vs no TGF-beta) and the effects of dynamic loading on MSC chondrogenesis (loading vs free-swelling).
Project description:Long-term dynamic compression enhanced the mechanical properties of MSC-seeded constructs only when loading was initiated after 21 days of chondrogenic differentiation. This study examined the molecular differences of chondrogenic MSCs compared to undifferentiated MSCs (TGF-beta vs no TGF-beta) and the effects of dynamic loading on MSC chondrogenesis (loading vs free-swelling). Free-swelling MSC-seeded constructs were cultured for 21 days in chemically defined media. Chondrogenesis was induced with TGF-beta3. Undifferentiated controls were maintained in parallel. After 21 days of chondrogenic differentiation, a subset of constructs were subjected to 21 days of dynamic compressive loading. On days 21 and 42, construct mechanical properties and biochemical content were assessed. Microarray analysis was carried out on day 3, day 21 and day 42 constructs. 6 arrays.
Project description:Modulating beta-catenin signaling has attractive therapeutic potential in cancer immunotherapy. Various studies have found that beta-catenin can mediate immune evasion in cancer and promote anti-inflammatory features of antigen-presenting dendritic cells. Multiple small-molecule compounds that inhibit Wnt/beta-catenin signaling are currently in clinical development, but none have reached routine clinical use. Thus, new inhibitors of beta-catenin signaling are desirable. This dataset is the result of an investigation of the effect of small molecular compounds axitinib, ICG-001, nitazoxanide, orlistat, and XAV-939 on the maturation capacity of monocyte-derived dendritic cells (moDC). Treatment of immature moDC was done in combination with the beta-catenin activator 6-BIO. Immature moDCs were obtained by isolating monocytes from PBMC using magnetic beads, which were then differentiated into moDCs using GM-CSF and IL-4 for four days. Compounds were added during the maturation of the moDCs, which was done by adding LPS to the cell culture. After the maturation period of 24 hours, the mature moDCs were collected and processed for RNA sequencing.
Project description:The β-catenin mutation is frequently observed in hepatoblastoma (HB), but the underlying mechanism by which Wnt/β-catenin signaling induces HB tumor formation is unknown. We found that expression of growth regulation by estrogen in breast cancer 1 (GREB1) depends on Wnt/β-catenin signaling in HB patients. GREB1 was localized to the nucleus where it bound Smad2/3 in a competitive manner with p300 and inhibited TGFβ signaling, thereby promoting HepG2 HB cell proliferation. Forced expression of β-catenin, YAP, and c-Met induced HB-like mouse liver tumor (BYM mice), with an increase in GREB1 expression and HB markers. Depletion of GREB1 strongly suppressed marker gene expression and HB-like liver tumorigenesis, and instead enhanced TGFβ signaling in BYM mice. Furthermore, antisense oligonucleotides for GREB1 suppressed the formation of HepG2 cell-induced tumors and HB-like tumors in vivo. We propose that GREB1 is a novel target molecule of Wnt/β-catenin signaling and required for HB progression.
Project description:Neural crest cells (NCCs) are multipotent stem cells with a remarkable ability to differentiate into multiple cell lineages, including osteoblasts and chondrocytes. NCCs contribute to the majority of craniofacial skeleton, yet the molecular mechanisms regulating NCCs diversification into osteoblasts or chondrocytes remain poorly understood. We found that Yap and Taz function redundantly as key determinants of the osteogenesis versus chondrogenesis fate decision and differentiation in NCCs in vitro, ex vivo and in vivo, and Yap/Taz-deficiency in NCCs resulted in a switch from osteogenesis to chondrogenesis. Comprehensive analysis of unbiased datasets including CUT&RUN-seq and RNA-seq indicated that Yap/Taz directly regulate key genes that govern osteogenesis and chondrogenesis. During NCC-derived osteogenesis, Yap/Taz promote expression of osteogenic genes such as Runx2 and Sp7 but repress expression of chondrogenic genes such as Sox9 and Col2a1. Further, we found Yap/Taz directly interact with β-catenin in NCCs to coordinately promote osteoblast differentiation and repress chondrogenesis. Together our data indicate that Yap/Taz promote osteogenesis in NCCs by preventing chondrogenesis, partly through interactions with the Wnt-β-catenin pathway.
Project description:Roles of reactive perivascular astrocytes in dysregulation of the blood-brain barrier (BBB) function and cerebral perfusion are not well defined. Here, we investigated transformation of reactive astrocyte function for vascular repair after ischemic stroke by targeted deletion of astrocytic Na+/H+ exchanger isoform 1 in Gfap-CreERT2+/-;Nhe1f/f (Nhe1 Astro-KO) mice. Control Gfap-CreERT2+/-;Nhe1f/f (wild-type) mice displayed BBB damage (elevated endothelial transcytosis and intracellular vesicles) and persistent cerebral hypoperfusion in an ischemic stroke model (transient middle cerebral artery occlusion). In contrast, Nhe1 Astro-KO mice exhibited significantly less endothelial transcytosis and vesicle formation, and increased angiogenesis and cerebral blood perfusion (CBF) post-stroke. Bulk RNA-sequencing transcriptome analysis of isolated GFAP+ reactive astrocytes from wild-type and Nhe1 Astro-KO ischemic brains revealed that ~177 genes were differentially upregulated, with the Wnt7a mRNA among the top upregulated genes, along with additional Wnt pathway genes (Wnt7b, Fzd9, Fzd10, and Ndp). Abundant Wnt7a/b and β-catenin protein expression was detected in cerebral vessels of Nhe1 Astro-KO ischemic brains but not in the wild-type brains. Selective activation of Wnt/β-catenin pathway in cerebral vessels of Nhe1 Astro-KO ischemic brains was further validated using the Wnt reporter line TCF/LEF::H2B-eGFP; Gfap-CreERT2+/-;Nhe1f/f mice. Lastly, the role of Wnt/β-catenin pathway in resistance of Nhe1 Astro-KO mice to stroke-mediated BBB damage was tested by administration of Wnt/β-catenin inhibitor XAV-939. Taken together, we report that transforming reactive astrocyte function by upregulating astrocytic Wnt/β-catenin signaling activity is a novel mechanism to reduce the BBB endothelial damage, stimulate vascular repair, and restore cerebral blood flow after ischemic stroke.
Project description:Human mesenchymal stem cells (MSCs) remain one of the best cell sources for cartilage, a tissue without regenerative capacity. However, MSC chondrogenesis is commonly induced through TGFβ, a pleomorphic growth factor without specificity for this lineage. Using tissue- and induced pluripotent stem cell-derived MSCs, we demonstrate an efficient and precise approach to induce chondrogenesis through Wnt/β-catenin antagonism alone without TGFβ. Compared to TGFβ, Wnt/β-catenin antagonism more rapidly induced MSC chondrogenesis without eliciting off-target lineage specification toward smooth muscle or hypertrophy; this was mediated through increasing N-cadherin levels and β-catenin interactions-key components of the adherens junctions (AJ)-and increasing cytoskeleton-mediated condensation. Validation with transcriptomic analysis of human chondrocytes compared to MSCs and osteoblasts showed significant downregulation of Wnt/β-catenin and TGFβ signaling along with upregulation of α-catenin as an upstream regulator. Our findings underscore the importance of understanding developmental pathways and structural modifications in achieving efficient MSC chondrogenesis for translational application.
Project description:Canonical Wnt/β-catenin signalling is an essential regulator of various cellular functions throughout development and adulthood. Aberrant Wnt/β-catenin signalling also contributes to various pathologies including cancer, necessitating an understanding of cell context dependent mechanisms regulating this pathway. Since protein-protein interactions underpin β-catenin function and localization, we sought to identify novel β-catenin interacting partners by affinity purification coupled with tandem mass spectrometry in vascular smooth muscle cells (VSMCs), where β-catenin is involved in both physiological and pathological control of cell proliferation. Here, we report novel components of the VSMC β-catenin interactome.
Project description:Canonical Wnt/B-catenin signaling is frequently dysregulated in myeloid leukemias and is implicated in leukemogenesis. Nuclear-localized β-catenin is indicative of active Wnt signaling and is frequently observed in acute myeloid leukemia (AML) patients; however, some patients exhibit little or no β-catenin nuclear-localization even where cytosolic B-catenin is abundant. Differential propensity for nuclear-localized β-catenin is also observed in cell lines. To investigate the factors mediating the nuclear-localization of B-catenin we carried out a nuclear/cytoplasmic proteomic analysis of the B-catenin interactome in myeloid leukemia cells. From this we identified hundreds of putative novel B-catenin-interactors. Comparison of interacting factors between Wnt-responsive cells (high nuclear B-catenin, K562/HEL) versus Wnt-unresponsive cells (low nuclear B-catenin, ML1) suggested the established interactor, LEF1, is a key factor mediating the nuclear-localization of B-catenin in myeloid leukemia. The relative levels of nuclear LEF1 and B-catenin were tightly correlated in both cell lines and in primary AML blasts. Furthermore, LEF1 knockdown inhibited B-catenin nuclear-localization and transcriptional activation in Wnt-responsive cells. Conversely, LEF1 overexpression was able to promote both nuclear-localization and B-catenin-dependent transcriptional responses in previously Wnt-unresponsive cells. This study is the first to present a B-catenin interactome in hematopoietic cells and reveals LEF1 as a critical regulator of canonical Wnt signaling in myeloid leukemia.