Project description:Introduction: Cataracts are the world’s leading cause of reversible blindness. Although cataract formation is commonly initiated by lens fiber cell defects, cataractogenesis can be characterized by aberrant proliferation and migration of lens epithelial cells, particularly in posterior capsule opacification. Subsequent overproduction of extracellular matrix components such as fibronectin and collagen by epithelial cells is associated with fibrosis of the lens. Little is known about the role of platelet-derived growth factor receptor β (PDGFRβ) in lens fibrosis. Here, we investigated mice with a conditional knock-in driving mesenchymal-specific PDGFRβ hyperactivation (Fsp1-cre;Pdgfrb+/D849V), which consistently develop cataracts at a young age. Methods: Lenses from Fsp1-cre;Pdgfrb+/D849V mice and age-matched controls were dissected and visualized via microscopy from 9-15 weeks. Early transcriptional changes were investigated between 10-12 day old Fsp1-cre;Pdgfrb+/D849V and control mice via RNA sequencing followed by gene set enrichment analysis. Confirmation of RNA sequencing results and mechanistic investigation of PDGFRβ-induced cataractogenesis were determined in lenses isolated from 15-week-old Fsp1-cre;Pdgfrb+/D849V and control mice. Results: Gross examination of cataractous lenses from Fsp1-cre;Pdgfrb+/D849V mice revealed complete opacification by 15 weeks of age compared to no opacification in age-matched controls. Structural changes in the anterior, equatorial, and posterior lens were observed in histology. RNA sequencing revealed significant enrichment of gene sets related to extracellular matrix deposition and reorganization. Mechanistic investigation revealed major roles for TGFβ, SOCS2, and STAT5-IGF1 signaling axes in PDGFRβ-induced cataract formation. Conclusion: PDGFRβ promoted cataractogenesis by modulating pro-fibrotic extracellular matrix changes, likely through TGFβ, SOCS2, and the STAT5-IGF1 pathways. Future experiments will delineate the precise role of the STAT5-IGF1 signaling pathway in PDGFRβ-mediated fibrosis and the interplay between PDGFRβ and TGFβ in the lens and whether this signaling is targetable to modulate cataractogenesis.
Project description:T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive immature T-cell cancer. Mutations in IL7RA were analyzed genetically, but downstream effector functions such as STAT5A/B hyperactivation are poorly understood. Here, we studied the most frequent and clinically challenging STAT5BN642H driver in T-cell development and immature T-cell cancer onset and compared it to STAT5A hyperactive variants in transgenic mice. Enhanced STAT5 activity caused disrupted T-cell development and promoted an early T-cell progenitor (ETP)- ALL phenotype with upregulation of genes involved in T-cell receptor (TCR) signaling, even in absence of surface TCR. Importantly, TCR pathway genes were overexpressed in human T- ALL and mature T-cell cancers and activation of TCR pathway kinases was STAT5-dependent. We confirmed STAT5-binding to these genes using ChIP-seq analysis in human T-ALL cells, which were sensitive to pharmacologic inhibition by dual STAT3/5 degraders or ZAP70 tyrosine kinase blockers in vitro and in vivo. We provide first genetic and biochemical proof that STAT5A and STAT5B hyperactivation can initiate T-ALL through TCR pathway hijacking and suggest similar mechanisms for other T-cell cancers. Thus, STAT5 or TCR component blockade are targeted therapy options, particularly in patients with chemo-resistant clones carrying STAT5BN642H.
Project description:Insight into the role of Insulin-like Growth Factor (IGF) in development of lungs has come from the study of genetically modified mice. IGF1 is a key factor during lung development. IGF1 deficiency in the neonatal mouse causes respiratory failure collapsed alveoli and altered alveolar septa. To further characterize IGF1 function during lung development we analyzed Igf1-/- mouse prenatal lungs in a C57Bl/6 genetic background. Mutant lungs showed disproportional hypoplasia, disorganized extracellular matrix and dilated alveolar capillaries. IGF1 target genes during lung maturation were identified by analyzing RNA differential expression in Igf1-/- lungs using microarrays. Lungs from E18.5 were isolated from both Igf1+/+ wild type and Igf1-/- null mice and pooled to obtain RNA. Heterozygous male and female with a genetic background C57BL/6J were mated to obtain embryos at embrionic (E) stage 18.5 days post coitum (E18.5). 3 biological replicates per genotype.
Project description:Transcriptional profiling of mouse osteoclasts comparing control osteoclasts from Stat5 flox mice with osteoclasts from Stat5 cKO mice. Two-condition experiment, Stat5 flox cells vs. Stat5 cKO cells
Project description:Hematopoietic stem cell (HSC) generation in the aorta-gonads-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRβ signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRβ is involved. Here we show that PDGFRβ is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRβ+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRβ+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of these clinically important cells in vitro.
Project description:Hematopoietic stem cell (HSC) generation in the aorta-gonads-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRβ signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRβ is involved. Here we show that PDGFRβ is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRβ+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRβ+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of these clinically important cells in vitro.
Project description:Insight into the role of Insulin-like Growth Factor (IGF) in development of lungs has come from the study of genetically modified mice. IGF1 is a key factor during lung development. IGF1 deficiency in the neonatal mouse causes respiratory failure collapsed alveoli and altered alveolar septa. To further characterize IGF1 function during lung development we analyzed Igf1-/- mouse prenatal lungs in a C57Bl/6 genetic background. Mutant lungs showed disproportional hypoplasia, disorganized extracellular matrix and dilated alveolar capillaries. IGF1 target genes during lung maturation were identified by analyzing RNA differential expression in Igf1-/- lungs using microarrays.
Project description:Transcriptional profiling of mouse osteoclasts comparing control osteoclasts from Stat5 flox mice with osteoclasts from Stat5 cKO mice.
Project description:Recurrent gain-of-function mutations in the transcription factor STAT5 have been detected in PTCL, an aggressive, heterogeneous disease, for which currently no targeted therapy exists. Here we investigated whether constitutive activation of STAT5 suffices to drive PTCL and whether inhibition of the JAK/STAT pathway offers a novel therapeutic opportunity in this disease. We found pronounced STAT5 expression and activity in patients from different PTCL subsets. To mimic high STAT5 activity we expressed a hyperactive STAT5A variant (termed vcS5) in the hematopoietic lineage in transgenic mice. vcS5-transgenic animals developed a lethal PTCL-like disease with full penetrance, characterized by massive expansion of CD8+ T-cells and destructive organ-infiltration. Adoptive transfer of vcS5-expressing CD8+ T-cell rapidly induced the disease in immunocompetent recipient mice. Neoplastic vcS5-T-cells displayed cytokine-hypersensitivity and showed activated, memory CD8+ T-lymphocyte characteristics. Histo-pathological analysis as well as mRNA expression profiles of vcS5 mice was closely correlated with distinct human lymphoma subtypes, including PTCL. Treatment of murine and human PTCL cell lines with the clinical JAK inhibitor Ruxolitinib or a selective STAT5 SH2 domain inhibitor induced cell death. Thus, our results demonstrate that enhanced STAT5 signaling drives PTCL development and suggest inhibition of the JAK/STAT5 pathway as a valuable therapeutic option for patients suffering from these aggressive lymphomas.