Project description:β-Catenin is a regulator of cutaneous wound repair. The expression of genes that are modulated in response to changes in β-Catenin levels (stabilization and downregulation) in cutaneous mouse wounds, post injury, during the proliferative phase of repair, was investigated. We are particularly interested in genes that are modulated (in opposite directions) in response to both the induction (stabilization) versus downregulation of β-Catenin. To investigate this, conditional β-Catenin stabilized (Harada, N., et al. EMBO J. 1999 Nov 1;18(21):5931-42) mice were injected with either a Cre-expressing adenovirus, or a GFP-expressing control virus, three days following injury, and wounds were harvested eight days post injury. For conditional knockdown of β-Catenin, mice generated from a cross between conditional β-Catenin knockdown mice (Brault, V. et al., Development. 2001 Apr;128(8):1253-64), and mice that express a tamoxifen-inducible form of Cre (Hayashi, S., and McMahon, A.P., Dev Biol. 2002 Apr 15;244(2):305-18), were treated with Tamoxifen for five days, beginning at the third day after injury. Wounds were harvested eight days after wounding. This provides insight into the identities of genes modulated in response to changes in β-Catenin levels during the proliferative stage of cutaneous wound repair.
Project description:β-Catenin is a regulator of cutaneous wound repair. The expression of genes that are modulated in response to changes in β-Catenin levels initiated prior to injury was investigated during the proliferative phase of repair. We are particularly interested in genes that are modulated (in opposite directions) in response to both the induction ('stabilization') versus downregulation of β-Catenin. To investigate this, conditional β-Catenin stabilized mice (Harada, N., et al. EMBO J. 1999 Nov 1;18(21):5931-42) were injected with either a Cre-expressing adenovirus, or a GFP-expressing control virus, four days prior to injury, and wounds were harvested eight days following injury. For conditional knockdown of β-Catenin, mice generated from a cross between conditional β-Catenin knockdown mice (Brault, V. et al., Development. 2001 Apr;128(8):1253-64), and mice that express a tamoxifen-inducible form of Cre (Hayashi, S., and McMahon, A.P., Dev Biol. 2002 Apr 15;244(2):305-18), were treated with Tamoxifen for five days prior to injury. Wounds were harvested eight days after wounding. This provides insight into gene expression changes that occur during the proliferative stage of cutaneous wound repair in response to changes in β-Catenin levels initiated before/at the time of injury.
Project description:Transformation of post-myeloproliferative neoplasms into secondary (s) AML exhibit poor clinical outcome. In addition to increased JAK-STAT and PI3K-AKT signaling, post-MPN sAML blast progenitor cells (BPCs) demonstrate increased nuclear β-catenin levels and TCF7L2 (TCF4) transcriptional activity. Knockdown of β-catenin or treatment with BC2059 that disrupts binding of β-catenin to TBL1X (TBL1) depleted nuclear β-catenin levels. This induced apoptosis of not only JAKi-sensitive but also JAKi-persister/resistant post-MPN sAML BPCs, associated with attenuation of TCF4 transcriptional targets MYC, BCL-2 and Survivin. Co-targeting of β-catenin and JAK1/2 inhibitor ruxolitinib (rux) synergistically induced lethality in post-MPN sAML BPCs and improved survival of mice engrafted with human sAML BPCs. Notably, co-treatment with BET protein degrader ARV-771 and BC2059 also synergistically induced apoptosis and improved survival of mice engrafted with JAKi-sensitive or JAKi-persister/resistant post-MPN sAML cells. These preclinical findings highlight potentially promising anti-post-MPN sAML activity of combination of β-catenin and BETP antagonists against post-MPN sAML BPCs.
Project description:We inflicted full thickness excisional wounds in the back skin of C57BL/6 wild-type mice. Injury-associated macrophages were isolated from wound tissue during the early inflammatory phase (4 days post injury) and in the late, scar forming phase (14 days post injury), sorted by flow cytometry (CD45+CD11b+F4/80+ wound cells), and subjected to RNAsequencing.
Project description:Transcription factors harbour defined intrinsically disordered regulatory regions, which raises the question of how they mediate binding to structured co-regulators and how this regulates activity. Here, we present a detailed molecular regulatory mechanism of Forkhead box O4 (FOXO4) by the structured transcriptional co-regulator β-catenin. We find that the largely disordered FOXO4 C-terminal region, which contains its transactivation domain binds β-catenin through two defined interaction sites, and this is regulated by combined PKB/AKT- and CK1-mediated phosphorylation. Binding of β-catenin competes with the auto-inhibitory interaction of the FOXO4 disordered region with its DNA-binding forkhead domain, and thereby enhances FOXO4 transcriptional activity. Furthermore, we show that binding of the β-catenin inhibitor protein ICAT is compatible with FOXO4 binding to β-catenin, suggesting that ICAT acts as a molecular switch between anti-proliferative FOXO and pro-proliferative Wnt/TCF/LEF signalling. Together these data illustrate how the interplay of intrinsically disordered regions, post-translational modifications and co-factor binding contribute to transcription factor function. Highlights • The interaction network between FOXO4 and β-catenin was deciphered • FOXO4 auto-inhibition interferes with DNA binding and is counter-acted by β-catenin • FOXO4 exists in multiple conformations regulated by phosphorylation and co-factors • ICAT switches between FOXO4 and TCF/LEF transcription factors
Project description:Renal repair after injury is dependent on clonal expansion of proliferation competent cells. In the human kidney, the expression of CD133+ characterizes a population of resident scattered cells with resistance to damage and ability to proliferate. However, the biological function of the CD133 molecule is unknown. We found by RNA sequencing that cells undergoing cisplatin damage lost the CD133 signature and acquired metanephric mesenchymal and regenerative genes such as SNAIL1, KLF4, SOX9 and WNT3. CD133 was reacquired in the recovery phase. Lack of CD133 was specifically correlated with deregulation of the Wnt signalling and E-cadherin pathway and, functionally, limited cell proliferation after injury. By immunoprecipitation, CD133 appeared to form a complex with E-cadherin and β-catenin. In parallel, CD133-Kd cells showed lower β-catenin levels in basal condition and after Wnt pathway activation and reduced TCF/LEF promoter activation in respect to CD133+ cells. Finally, the lack of CD133 impaired generation of nephrospheres while favored senescence. These data indicate that CD133 may act as a permissive factor for beta-catenin signalling, preventing its degradation in the cytoplasm. Therefore, CD133 itself appears to play a functional role in renal tubular repair trough maintenance of proliferative response and control of senescence.
Project description:In colorectal cancer, p53 is commonly inactivated, associated with chemo-resistance, and marks the transition from non-invasive to invasive disease. Cancers, including colorectal cancer, are thought to be diseases of aberrant stem cell populations, as stem cells are able to self-renew, making them long-lived enough to acquire mutations necessary to manifest the disease. We have shown that extracts from sweet sorghum stalk components eliminate colon cancer stem cells (CCSC) in a partial p53-dependent fashion. However, the underlying mechanisms are unknown. In the present study, CCSC were transfected with short hairpin-RNA against p53 (CCSC p53 shRNA) and treated with sweet sorghum phenolics extracted from different plant components (dermal layer, leaf, seed head and whole plant). While all components demonstrated anti-proliferative and pro-apoptotic effects in CCSC, phenolics extracted from the dermal layer and seed head were more potent in eliminating CCSC by elevating caspases 3/7 activity, PARP cleavage, and DNA fragmentation in a p53-dependent and p53-independent fashion, respectively. Further investigations revealed that the anti-proliferative and pro-apoptotic effects were associated with decreases in beta-catenin protein levels, and beta-catenin targets cyclin D1, cMyc, and survivin. These results suggest that the anti-proliferative and pro-apoptotic effects of sweet sorghum extracts against human colon cancer stem cells are via suppression of Wnt/beta-catenin pro-survival signaling in a p53-dependent (dermal layer) and partial p53-independent (seed head) fashion. LCMS used to identify phenolic compounds associated with extract activity
Project description:The vitamin D receptor (VDR) regulates cell proliferation and differentiation including epidermal keratinocytes by modulating transcription of its target genes. We are investigating the role of VDR in epidermal stem cells and their progenies in the regeneration process of epidermis and hair in the skin. VDR null mice are utilized in which VDR is specifically deleted in keratin 14 (K14) expressing keratinocytes by Cre-lox strategy. The impact of VDR deletion was evaluated by comparison of VDR null mice with no cre littermate control mice. The VDR was abundantly expressed in potential epidermal stem cells including basal cells in interfollicular epidermis (IFE), and in CD34 expressing bulge keratinocytes in hair follicles. Gene expression profiles and subsequent pathway analysis of stem cell enriched keratinocyte populations revealed that the VDR deletion significantly suppressed β-catenin signaling as well as VDR signaling. The role of VDR in epidermal stem cells was studied during hair follicle cycling and wound healing processes. The epidermal stem cells were not appropriately stimulated by hair depilation, and did not reinitiate anagen in the hair follicles resulting in a failure of hair regrowth. In addition, the stem cells were not fully activated after full thickness wounds were generated in VDR null skin under a low calcium diet to suppress compensation pathways. Cell proliferation was not fully induced in potential stem cells located in both IFE and hair follicles near the wounding edges, and re-epithelialization rate was delayed in VDR null skin. Gene expression profiling of the wounded skin (3 days after injury) indicated that β-catenin signaling was not fully induced in VDR null skin comparable to that observed in β-catenin null mice. The β-catenin target genes including Axin2 and cell cycle regulators involved in epidermal stem cell function were not induced in the edges of the wound of VDR null skin. These results demonstrated that VDR plays an essential role in hair cycling and wound healing processes through regulation of β-catenin signaling in epidermal stem cells and their progenies. n=3 CON and KO (each sample contain RNA isolated from wounded or nonwounded skins excised from 3 mice)