Project description:Chemotherapy-related endothelial damage contributes to the early development of cardiovascular morbidity in testicular cancer patients. We aimed to identify relevant mechanisms of and search for candidate biomarkers for this endothelial damage. Human micro-vascular endothelial cells (HMEC-1) were exposed to bleomycin or cisplatin with untreated samples as control. 18k cDNA microarrays were used. Gene expression differences were analysed at single gene level and in gene sets clustered in biological pathways and validated by qRT-PCR. Protein levels of a candidate biomarker were measured in testicular cancer patient plasma before, during and after bleomycin-etoposide-cisplatin chemotherapy, and related to endothelial damage biomarkers (von Willebrand Factor (vWF), high-sensitivity C-Reactive Protein (hsCRP)). Microarray data identified several genes with highly differential expression; e.g. Growth Differentiation Factor 15 (GDF-15), Activating Transcription Factor 3 (ATF3) and Amphiregulin (AREG). Pathway analysis revealed strong associations with ‘p53’ and ‘Diabetes Mellitus’ gene sets. Based on known function, we measured GDF-15 protein levels in 41 testicular patients during clinical follow-up. Pre-chemotherapy GDF-15 levels equalled controls. Throughout chemotherapy GDF-15, vWF and hsCRP levels increased, and were correlated at different time-points. An unbiased approach in a preclinical model revealed genes related to chemotherapy-induced endothelial damage, like GDF-15. The increases in plasma GDF-15 levels in testicular cancer patients during chemotherapy and its association with vWF and hsCRP suggest that GDF-15 is a potentially useful biomarker related to endothelial damage.
Project description:Growth and differentiation factor-15 (GDF-15), a member of the TGF-β superfamily, exhibits elevated expression in various tumor types, often linked to disease aggressiveness. In this study, which used patient-derived xenografts and paired cell lines of epithelioid hemangioendothelioma (EHE), it was found that EHE cells produce and release GDF-15. Furthermore, the mTOR inhibitor sirolimus was observed to inhibit GDF-15 expression and release by down-regulating ATF4 and ATF5 transcription factors. To assess the clinical relevance of GDF-15 in EHE, which can manifest as both relatively indolent and exceptionally aggressive forms, circulating GDF-15 levels were assessed in two independent cohorts of EHE patients, one retrospective and one prospective. The results provided evidence of an association between circulating GDF-15 levels and the aggressiveness of EHE. In summary, these findings suggest that GDF-15 can serve as a biomarker for EHE aggressiveness and may have implications for monitoring the effectiveness of sirolimus in EHE patients.
Project description:Growth and differentiation factor-15 (GDF-15), a member of the TGF-β superfamily, exhibits elevated expression in various tumor types, often linked to disease aggressiveness. In this study, which used patient-derived xenografts and paired cell lines of epithelioid hemangioendothelioma (EHE), it was found that EHE cells produce and release GDF-15. Furthermore, the mTOR inhibitor sirolimus was observed to inhibit GDF-15 expression and release by down-regulating ATF4 and ATF5 transcription factors. To assess the clinical relevance of GDF-15 in EHE, which can manifest as both relatively indolent and exceptionally aggressive forms, circulating GDF-15 levels were assessed in two independent cohorts of EHE patients, one retrospective and one prospective. The results provided evidence of an association between circulating GDF-15 levels and the aggressiveness of EHE. In summary, these findings suggest that GDF-15 can serve as a biomarker for EHE aggressiveness and may have implications for monitoring the effectiveness of sirolimus in EHE patients.
Project description:RGC differentiation is tightly controlled by extrinsic and intrinsic factors. Growth and differentiation factor 15 (GDF-15) promotes RGC differentiation, opposite to GDF-11 which inhibits RGC differentiation, both in the mouse retina and in human stem cells. To deepen our understanding of how these two closely related molecules confer opposing effects on retinal development, here we assess the transcriptional profiles of mouse retinal progenitors exposed to exogenous GDF-11 or -15. We find a dichotomous effect of GDF-15 on RGC differentiation, decreasing RGCs expressing residual pro-proliferative genes and increasing RGCs expressing non-proliferative genes, suggestive of greater RGC maturation. Furthermore, GDF-11 promoted the differentiation of photoreceptors and amacrine cells. These data enhance our understanding of the mechanisms underlying the differentiation of RGCs and photoreceptors from retinal progenitors and suggest new approaches to the optimization of protocols for the differentiation of these cell types.
Project description:Glioblastoma (GBM) remains a challenging malignancy with dismal prognoses despite aggressive treatment regimens. Intratumoral heterogeneity contributes to therapeutic resistance, with roles for stem cell-like brain tumor initiating cells (GBMs), glioma associated macrophages (GAMs), and communication between them. GAMs are derived from infiltrating lymphocytes, and monocyte migration is increased by GBM cell release of extracellular vesicles, including exosomes. GBM survival is promoted by the glucose transporter GLUT3, which was recently shown to alter macrophage activation states. We found that GBM-derived exosomes contain GLUT3 and that exosomes from GLUT3 expressing GBMs significantly increased monocyte migration in comparison to controls. Monocytes transfected with GLUT3 (but not GLUT1) also had significantly increased migration, demonstrating a direct role for GLUT3 in monocytes migration. Analysis of the transcriptome of exosome treated monocytes demonstrated that exosomes derived from GLUT3 expressing GBMs increasedGDF-15in monocytes. GDF-15 is a known regulator of monocyte migration, and we determined that knockdown of GDF-15 blocked the migration induced by GBM-derived exosomes. As GDF-15 induced monocyte migration is thought to involve MMP12, we next evaluated MMP12 as a potential mediator of the pro-migratory phenotype.MMP12was significantly increased in monocytes upon treatment with exosomes derived from GLUT3 expressing GBMs as was MMP12 activity. Together, our findings suggest a novel mechanism by which GBMs facilitate immune evasion and tumor progression: GBM-derived exosomes transfer GLUT3 to monocytes to increase a GDF-15/MMP12 pathway that promotes monocyte migration. The data also highlight the importance of understanding and targeting cell-cell interactions to improve glioblastoma treatment.
Project description:Aging is the most important risk factor for the development of cardiovascular diseases. Senescent cells release plethora of factors commonly known as the senescence-associated secretory phenotype (SASP), which can modulate the normal function of the vascular wall. It is currently not well understood if and how endothelial cell senescence can affect adventitial niche. The aim of this study was to characterize oxidative stress-induced endothelial cells senescence and identify their paracrine effects on the primary cell type of the adventitia, the fibroblasts. Human aortic endothelial cells (HAEC) were treated with hydrogen peroxide to induce premature senescence. Mass spectrometry analysis identified several proteomic changes in senescent HAEC with top upregulated secretory protein growth differentiation factor 15 (GDF-15). Treatment of the human adventitial fibroblast cell line (hAdv cells) with conditioned medium (CM) from senescent HAEC resulted in alterations in the proteome of hAdv cells identified in mass spectrometry analysis. Majority of differentially expressed proteins in hAdv cells treated with CM from senescent HAEC were involved in the uptake and metabolism of lipoproteins, mitophagy and ferroptosis. We next analyzed if some of these changes and pathways might be regulated by GDF-15. We found that recombinant GDF-15 affected some ferroptosis-related factors (e.g. ferritin) and decreased oxidative stress in the analyzed adventitial fibroblast cell line, but it had no effect on erastin-induced cell death. Contrary, silencing of GDF-15 in hAdv cells was protective against this ferroptotic stimuli. Our findings provide a better understanding of the biology of senescent cells and can be of importance for potential therapeutic strategies targeting cell senescence or ferroptosis to alleviate vascular diseases.
Project description:Muscle regeneration is the result of the concerted action of multiple cell types driven by the temporarily controlled phenotype switches of infiltrating monocyte-derived macrophages. Proinflammatory macrophages transition into a phenotype that drives tissue repair through the production of effectors such as growth factors. This orchestrated sequence of regenerative inflammatory events, which we termed Regeneration-Promoting Program (RPP), is essential for proper repair. However, it is not well understood how specialized repair-macrophage identity develops in the RPP at the transcriptional level and how induced macrophage-derived factors coordinate tissue repair. Gene expression kinetics-based clustering of blood circulating Ly6Chigh, infiltrating inflammatory Ly6Chigh, and reparative Ly6Clow macrophages, isolated from injured muscle, identified the TGF-beta superfamily member, GDF-15, as a component of the RPP. Myeloid GDF-15 is required for proper muscle regeneration following acute sterile injury, as revealed by gain- and loss-of-function studies. Mechanistically, GDF-15 acts both on proliferating myoblasts and muscle-infiltrating myeloid cells. Epigenomic analyses of upstream regulators of Gdf15 expression identified that it is under the control of nuclear receptors RXR/PPARg. Finally, immune single-cell RNA-seq profiling revealed that Gdf15 is coexpressed with other known muscle regeneration-associated growth factors, and their expression is limited to a unique subpopulation of repair-type macrophages (Growth Factor-Expressing Macrophages, GFEM).
Project description:Muscle regeneration is the result of the concerted action of multiple cell types driven by the temporarily controlled phenotype switches of infiltrating monocyte-derived macrophages. Proinflammatory macrophages transition into a phenotype that drives tissue repair through the production of effectors such as growth factors. This orchestrated sequence of regenerative inflammatory events, which we termed Regeneration-Promoting Program (RPP), is essential for proper repair. However, it is not well understood how specialized repair-macrophage identity develops in the RPP at the transcriptional level and how induced macrophage-derived factors coordinate tissue repair. Gene expression kinetics-based clustering of blood circulating Ly6Chigh, infiltrating inflammatory Ly6Chigh, and reparative Ly6Clow macrophages, isolated from injured muscle, identified the TGF-beta superfamily member, GDF-15, as a component of the RPP. Myeloid GDF-15 is required for proper muscle regeneration following acute sterile injury, as revealed by gain- and loss-of-function studies. Mechanistically, GDF-15 acts both on proliferating myoblasts and muscle-infiltrating myeloid cells. Epigenomic analyses of upstream regulators of Gdf15 expression identified that it is under the control of nuclear receptors RXR/PPARg. Finally, immune single-cell RNA-seq profiling revealed that Gdf15 is co-expressed with other known muscle regeneration-associated growth factors, and their expression is limited to a unique subpopulation of repair-type macrophages (Growth Factor-Expressing Macrophages, GFEM).
Project description:Muscle regeneration is the result of the concerted action of multiple cell types driven by the temporarily controlled phenotype switches of infiltrating monocyte-derived macrophages. Proinflammatory macrophages transition into a phenotype that drives tissue repair through the production of effectors such as growth factors. This orchestrated sequence of regenerative inflammatory events, which we termed Regeneration-Promoting Program (RPP), is essential for proper repair. However, it is not well understood how specialized repair-macrophage identity develops in the RPP at the transcriptional level and how induced macrophage-derived factors coordinate tissue repair. Gene expression kinetics-based clustering of blood circulating Ly6Chigh, infiltrating inflammatory Ly6Chigh, and reparative Ly6Clow macrophages, isolated from injured muscle, identified the TGF-beta superfamily member, GDF-15, as a component of the RPP. Myeloid GDF-15 is required for proper muscle regeneration following acute sterile injury, as revealed by gain- and loss-of-function studies. Mechanistically, GDF-15 acts both on proliferating myoblasts and muscle-infiltrating myeloid cells. Epigenomic analyses of upstream regulators of Gdf15 expression identified that it is under the control of nuclear receptors RXR/PPARg. Finally, immune single-cell RNA-seq profiling revealed that Gdf15 is coexpressed with other known muscle regeneration-associated growth factors, and their expression is limited to a unique subpopulation of repair-type macrophages (Growth Factor-Expressing Macrophages, GFEM).
Project description:We performed single-nuclei RNAseq of Sprague Dawley rat area postrema and nucleus tractus solitarius brain samples from animals treated with GDF-15 to identify cellular subtype specific changes in the neural transcriptome.