Project description:Pericytes/vascular smooth muscle cells (VSMCs), regulated by platelet-derived growth factor receptor β (PDGFRβ) signaling, play important roles in endothelial survival and vascular stability. Here we report that treatment with imatinib, an inhibitor of PDGFRβ, led to significant tumor growth impairment associated with increased apoptosis in human lymphoma xenografts including Farage, Karpas422 and OCI-Ly7 in SCID mice. Confocal analysis of the tumor tissue showed decreased microvessel density, decreased vascular flow, and increased vascular leak in the imatinib-treated cohorts. Imatinib targeted tumor-associated PDGFRβ+ pericytes in vivo by inducing apoptosis and disruption of the PDGFRβ+ perivascular network, and PDGFRβ+ VSMC in vitro by inhibition of proliferation. FACS analysis of mononuclear cell suspension of tumor tissues revealed decreased mature pericytes and endothelial cells, as well as their progenitors with imatinib treatment. Compared to imatinib, treatment with anti-PDGFRβ monoclonal antibody partially inhibited the growth of Farage lymphomas. Lastly, microarray analysis of differentially expressed genes in PDGFRβ+ VSMC following imatinib treatment showed significant down-regulation of genes implicated in proliferation, survival and angiogenesis, including those within PI3K/AKT and MAPK/ERK1/2 pathways downstream of PDGFRβ signaling. Taken together, targeting PDGFRβ+ pericytes in lymphoma presents a novel and complementary target to endothelial cells for efficacious antiangiogenic therapy. PDGFRb+ murine vascular smooth muscle cells (VSMCs) were treated in 10 uM imatinib for 24 or 48 hours. Gene expression changes in response to imatinib treatment were examined using NimbleGen MM8_60mer gene expression microarrays by comparing expression patterns at 24- and 48-hours treatment to the baseline level (0 hours).
Project description:Pericytes/vascular smooth muscle cells (VSMCs), regulated by platelet-derived growth factor receptor β (PDGFRβ) signaling, play important roles in endothelial survival and vascular stability. Here we report that treatment with imatinib, an inhibitor of PDGFRβ, led to significant tumor growth impairment associated with increased apoptosis in human lymphoma xenografts including Farage, Karpas422 and OCI-Ly7 in SCID mice. Confocal analysis of the tumor tissue showed decreased microvessel density, decreased vascular flow, and increased vascular leak in the imatinib-treated cohorts. Imatinib targeted tumor-associated PDGFRβ+ pericytes in vivo by inducing apoptosis and disruption of the PDGFRβ+ perivascular network, and PDGFRβ+ VSMC in vitro by inhibition of proliferation. FACS analysis of mononuclear cell suspension of tumor tissues revealed decreased mature pericytes and endothelial cells, as well as their progenitors with imatinib treatment. Compared to imatinib, treatment with anti-PDGFRβ monoclonal antibody partially inhibited the growth of Farage lymphomas. Lastly, microarray analysis of differentially expressed genes in PDGFRβ+ VSMC following imatinib treatment showed significant down-regulation of genes implicated in proliferation, survival and angiogenesis, including those within PI3K/AKT and MAPK/ERK1/2 pathways downstream of PDGFRβ signaling. Taken together, targeting PDGFRβ+ pericytes in lymphoma presents a novel and complementary target to endothelial cells for efficacious antiangiogenic therapy.
Project description:Pulmonary vascular development is essential for alveolarization, and disruption of this process contributes to bronchopulmonary dysplasia (BPD) pulmonary pathology. Proper vascular development requires an orchestration of many cell types within the lung. However, the mechanisms by which pericytes support the endothelium in the postnatal lung remain poorly understood. Here, we identify FOXF2 as a critical transcription factor that governs pericyte maturation and function during postnatal lung development and regeneration. FOXF2 expression in pericytes increases postnatally and is selectively downregulated following neonatal hyperoxic injury. Pdgfrb-CreER mediated Foxf2 deletion in pericytes leads to pericyte hyperplasia, impaired migration, reduced expression of angiogenic factors such as ANGPTL4, and exacerbated alveolar simplification in a neonatal murine model of BPD. Transcriptomic and genomic studies demonstrate that FOXF2 maintains chromatin accessibility at pro-angiogenic loci and modulates paracrine signaling essential for endothelial regeneration. Loss of FOXF2 disrupts pericyte–endothelial crosstalk, impairing angiogenesis and alveolar repair during injury. Our study identifies FOXF2 as a central transcriptional regulator of pericyte-driven vascular niche function in the neonatal lung and underscores the pathogenic role of dysfunctional pericytes in BPD.
Project description:Pulmonary vascular development is essential for alveolarization, and disruption of this process contributes to bronchopulmonary dysplasia (BPD) pulmonary pathology. Proper vascular development requires an orchestration of many cell types within the lung. However, the mechanisms by which pericytes support the endothelium in the postnatal lung remain poorly understood. Here, we identify FOXF2 as a critical transcription factor that governs pericyte maturation and function during postnatal lung development and regeneration. FOXF2 expression in pericytes increases postnatally and is selectively downregulated following neonatal hyperoxic injury. Pdgfrb-CreER mediated Foxf2 deletion in pericytes leads to pericyte hyperplasia, impaired migration, reduced expression of angiogenic factors such as ANGPTL4, and exacerbated alveolar simplification in a neonatal murine model of BPD. Transcriptomic and genomic studies demonstrate that FOXF2 maintains chromatin accessibility at pro-angiogenic loci and modulates paracrine signaling essential for endothelial regeneration. Loss of FOXF2 disrupts pericyte–endothelial crosstalk, impairing angiogenesis and alveolar repair during injury. Our study identifies FOXF2 as a central transcriptional regulator of pericyte-driven vascular niche function in the neonatal lung and underscores the pathogenic role of dysfunctional pericytes in BPD.
Project description:Pulmonary vascular development is essential for alveolarization, and disruption of this process contributes to bronchopulmonary dysplasia (BPD) pulmonary pathology. Proper vascular development requires an orchestration of many cell types within the lung. However, the mechanisms by which pericytes support the endothelium in the postnatal lung remain poorly understood. Here, we identify FOXF2 as a critical transcription factor that governs pericyte maturation and function during postnatal lung development and regeneration. FOXF2 expression in pericytes increases postnatally and is selectively downregulated following neonatal hyperoxic injury. Pdgfrb-CreER mediated Foxf2 deletion in pericytes leads to pericyte hyperplasia, impaired migration, reduced expression of angiogenic factors such as ANGPTL4, and exacerbated alveolar simplification in a neonatal murine model of BPD. Transcriptomic and genomic studies demonstrate that FOXF2 maintains chromatin accessibility at pro-angiogenic loci and modulates paracrine signaling essential for endothelial regeneration. Loss of FOXF2 disrupts pericyte–endothelial crosstalk, impairing angiogenesis and alveolar repair during injury. Our study identifies FOXF2 as a central transcriptional regulator of pericyte-driven vascular niche function in the neonatal lung and underscores the pathogenic role of dysfunctional pericytes in BPD.