Project description:Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre-ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context.
Project description:Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre-ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context.
Project description:Purpose: to determine cellular heterogeneity of mesenchymal Gli1-positive cells from colon using single cell RNAse (10xGenomics); Summary: We determined 8 disctinct sub-populations of mesenchymal cells, remaining non-Gli1 epithelial cells formed a distinct separete cluster serving as a internal control of the single cells sequencing procedure
Project description:The precise origin of newly formed alpha smooth muscle actin-positive (ACTA2+) cells appearing in non-muscularized vessels in the context of pulmonary hypertension (PH) is still debatable, although it is believed that they predominantly derive from pre-existing vascular smooth muscle cells (VSMCs). Here, Gli1Cre-ERT2; tdTomatoflox mice were used to lineage-trace GLI1+ cells in the context of PH using two independent models of vascular remodeling (VR) and reverse remodeling (RR): Hypoxia and cigarette-smoke exposure (SE). Hemodynamic measurements, right ventricular hypertrophy assessment, flow cytometry, and histological analysis of thick lung sections followed by state-of-the-art 3D reconstruction and quantification using Imaris software were used to investigate the contribution of GLI1+ cells to neo-muscularization of the pulmonary vasculature. The data show that GLI1+ cells are abundant around distal, nonmuscularized vessels during steady state, and that this lineage contributes to around 50% of newly formed ACTA2+ cell around these normally non-muscularized vessels. During RR, cells derived from the GLI1+ lineage are largely cleared in parallel to the reversal of muscularization. Partial ablation of GLI1+ cells greatly prevented VR in response to hypoxia and attenuated the increase in RVSP and right heart hypertrophy. Single-cell RNA sequencing (scRNA-seq) on sorted lineage-labeled GLI1+ cells revealed an Acta2high fraction of cells with pathways in cancer and MAPK signaling as potential players in reprogramming these cells during VR. Analysis of human lungderived material suggests that GLI1 signaling is overactivated in both Group 1 and Group 3 PH and can promote proliferation and myogenic differentiation. Our data highlight GLI1+ cells as an alternative cellular source of VSMCs in PH and suggest that these cells and the associated signaling pathways represent an important therapeutic target for further studies.
Project description:GLI1 is a transcription factor correlated to decreased survival in several cancers. We have identified SMARCA2 as a co-regulator that enhances GLI1-mediated transcriptional activity and functions through the C-terminal transcriptional activation domain of GLI1. Central domains including the ATPase motif of SMARCA2 physically interact with GLI1. Evaluation of DNA density indicates GLI1, like SMARCA2, can increase the DNA accessibility with a preference for sites distal to gene transcription start sites and outside the promoter regions (i.e. enhancers). The putative enhancers where accessibility is decreased by the knock down of GLI1 and SMARCA2 are located cis to genes, such as HHIP, that are regulated by GLI1 and implicated in cancer functions. At the putative enhancer for HHIP, the localization of SMARCA2 is at least partially dependent on GLI1’s presence. Understanding this transcriptional regulation by GLI1 and SMARCA2 through altering chromatin accessibility at enhances can provide additional therapeutic targets for cancers dependent on GLI1.
Project description:Increased expression of GLI1 is associated with poor prognosis for some breast cancer subtypes. A conditional transgenic GLI1 expressing mouse model, with or without heterozygous deletion of Trp53, was used to generate and study GLI1 induced mammary gland tumours. Tumour tissue was serially orthotopically transplanted for at least 10 generations in NSG mice.
Project description:The precise origin of newly formed alpha smooth muscle actin-positive (ACTA2+) cells appearing in non-muscularized vessels in the context of pulmonary hypertension (PH) is still debatable, although it is believed that they predominantly derive from pre-existing vascular smooth muscle cells (VSMCs). Here, Gli1Cre-ERT2; tdTomatoflox mice were used to lineage-trace GLI1+ cells in the context of PH using two independent models of vascular remodeling (VR) and reverse remodeling (RR): hypoxia and cigarette-smoke exposure (SE). Hemodynamic measurements, right ventricular hypertrophy assessment, flow cytometry, and histological analysis of thick lung sections followed by state-of-the-art 3D reconstruction and quantification using Imaris software were used to investigate the contribution of GLI1+ cells to neo-muscularization of the pulmonary vasculature. The data show that GLI1+ cells are abundant around distal, non-muscularized, vessels during steady state, and that this lineage contributes to around 50% of newly formed ACTA2+ cell around these normally non-muscularized vessels. During RR, cells derived from the GLI1+ lineage are largely cleared in parallel to the reversal of muscularization. Partial ablation of GLI1+ cells greatly prevented VR in response to hypoxia and attenuated the increase in RVSP and right heart hypertrophy. Single-cell RNA sequencing (scRNA-seq) on sorted lineage-labeled GLI1+ cells revealed an Acta2high fraction of cells with pathways in cancer and MAPK signaling as potential players in reprogramming these cells during VR. Analysis of human lung-derived material suggests that GLI1 signaling is overactivated in both Group 1 and Group 3 PH and can promote proliferation and myogenic differentiation. Our data highlight GLI1+ cells as an alternative cellular source of VSMCs in PH and suggest that these cells and the associated signaling pathways represent an important therapeutic target for further studies.
Project description:To clarify transcriptional target genes of GLI1 in human mammary epithelial cells and breast cancer cells, primary culture cells of human mammary epithelium HMEC and breast cancer cell line MCF-7 were lentivirally transduced by either GLI1 or its control LacZ. Their RNA samples were served for expression analysis using AGILENT human 8x60K cDNA microarray. Array analysis of HMEC and MCF-7 expressing either GLI1 or LacZ. 1 color method was employed.
Project description:Panc1 (human pancreatic adenocarcinoma cells) cells were transfected with control siRNA (targeting firefly luciferase, siLuc) or siRNA targeting GLI1 (siGLI1, Pool of four siRNAs). 72h following transfection, RNA was prepared for array analysis.
Project description:SHH signaling pathway is activated in many type of cancers. However, the role of its activation in particular type of cancer was poorly understood. The GLI family transcription factor GLI1 is the effector of Shh pathway activation and functions as oncogene. Our goal of research is to identify the GLI1 targets in desmoplastic medulloblastomas. We used microarrays to obtain the global gene expression profiles in cells transformed by GLI1 and identified distinct classes of genes by comparing with those of desmoplastic medulloblastomas