Project description:Therapeutic neo-vasculogenesis in vivo can be achieved by the co-transplantation of human endothelial colony-forming progenitor cells (ECFCs) with mesenchymal stem/progenitor cells (MSPCs).The underlying mechanism is not completely understood thus hampering the development of novel stem cell therapies.We hypothesized that proteomic profiling could be used to retrieve the in vivo signaling signature during the initial phase of human neo-vasculogenesis. ECFCs and MSPCs were therefore either transplanted alone or co-transplanted subcutaneously into immune deficient mice. Early cell signaling, occurring within the first 24 hours in vivo, was analyzed using antibody microarray proteomic profiling.Vessel formation and persistence were verified in parallel transplants for up to 24 weeks. Proteomic analysis revealed significant alteration of regulatory components including caspases, calcium/calmodulin-dependent protein kinase, DNA protein kinase,human ErbB2 receptor-tyrosine kinase as well as mitogen-activated protein kinases.Therapeutic candidate caspase-4 was selected from array results for targeting vascular network formation in vitro as well as modulating therapeutic vasculogenesis in vivo. As a proof-of-principle, caspase-4 and general caspase-blocking led to diminished endothelial network formation in vitro and significantly decreased vasculogenesis in vivo. Proteomic profiling ex vivo thus unraveled a signaling signature which can be targeted to modulate neo-vasculogenesis in vivo.
Project description:The CD4+ regulatory T (Treg) cell lineage comprises thymus-derived (t)Treg cells and peripherally induced (p)Treg cells. As a model for Treg cells, studies employ TGF-β-induced (i)Treg cells generated from CD4+ conventional T (Tconv) cells in vitro. Here, we describe the relationship of iTreg cells to tTreg and Tconv cells. Proteomic analysis revealed that iTreg, tTreg and Tconv cell populations each have a unique protein expression pattern. iTreg cells had very limited overlap in protein expression with tTreg cells, regardless of cell activation status and instead shared signaling and metabolic proteins with Tconv cells. tTreg cells had a uniquely modest response to CD3/CD28-mediated stimulation. As a benchmark, we used a previously defined proteomic signature that sets ex vivo naïve and effector phenotype Treg cells apart from Tconv cells and includes unique Treg cell properties (Cuadrado et al., Immunity, 2018). This Treg cell core signature was largely absent in iTreg cells. We also used a proteomic signature that distinguishes ex vivo effector Treg cells from Tconv cells and naïve Treg cells. This effector Treg cell signature was partially present in iTreg cells. In conclusion, iTreg cells are distinct from tTreg cells and share limited features with ex vivo Treg cells at the proteomic level.
Project description:Hematopoietic stem cells (HSCs) in the fetal liver mature from pre-HSCs that originate in the major arteries of the embryo. To generate HSCs from other cell sources it will be necessary to reproduce the maturation of HSCs from pre-HSCs ex vivo. We refined the markers used to purify pre-HSCs and HSCs matured ex vivo, and compared the transcriptomes of pre-HSCs, ex vivo matured HSCs, and fetal liver HSCs. We found that maturation of pre-HSCs into HSCs in vivo or ex vivo is accompanied by the downregulation of genes involved in embryonic development and vasculogenesis, and upregulation of genes involved in hematopoietic organ development, lymphoid development, and immune responses. Ex vivo matured HSCs more closely resemble fetal liver HSCs than pre-HSCs, but are not their molecular equivalents. We show that functional ex vivo-matured and fetal liver HSCs increase the expression of programmed death ligand 1 (PD-L1). PD-L1 does not mark all pre-HSCs, but cell surface PD-L1 was present on functional HSCs after ex vivo culture. PD-L1 signaling, however, is not required for engraftment of embryonic HSCs. Hence, up-regulation of PD-L1 is a correlate of, but not a requirement for HSC maturation.
Project description:Background. Dendritic cell (DC)-based neoantigen vaccination holds potential as a safe and effective adjuvant therapy for patients with early-stage, resectable NSCLC. DCs have the unique ability to elicit robust antitumoral T-cell responses, while neoantigens are ideal targets to elicit high-affinity T cell responses with excellent tumor specificity. Here, we present the results of a phase I clinical trial in which a novel DC vaccine targeting neoantigens was evaluated in six patients with early stage, resected NSCLC. Methods. Autologous monocyte-derived DCs loaded with neoantigens (Neo-mDCs) were manufactured according to a 4-day protocol. Neo-mDCs were injected intravenously following an intrapatient dose escalation scheme. Primary endpoint of the trial was safety. Secondary endpoints were feasibility, immunogenicity, and relapse-free survival. Results. Vaccine manufacturing was feasible in 6 of 10 patients. Toxicity was limited to grade 1-2 adverse events. Systemic T cell responses were observed in 5 out of 6 vaccinated patients and were dominated by CD8+ T cells, which could be detected ex vivo at high frequencies >1.5 years after the last dose. Furthermore, single cell analysis indicated that the CD8+ T cell responsive population was polyclonal and exhibited the near entire spectrum of T cell differentiation states, including a naïve-like state associated with long lasting memory, but excluding exhausted cell states. Three of six vaccinated patients experienced disease relapse.Conclusion. Neo-mDC vaccination is safe, feasible and induces polyclonal populations of neoantigen-specific T-cell responses containing long lasting memory and effector cells in early-stage NSCLC patients, suggesting clinical potential.
Project description:Background. Dendritic cell (DC)-based neoantigen vaccination holds potential as a safe and effective adjuvant therapy for patients with early-stage, resectable NSCLC, a tumor type typically characterized by high mutational loads. DCs have the unique ability to elicit robust antitumoral T-cell responses, while neoantigens are ideal targets to elicit high-affinity T cell responses with exquisite tumor specificity. Here, we present the results of a phase I clinical trial in which a novel DC vaccine targeting neoantigens was evaluated in six patients with early stage, resected NSCLC. Methods. Tumor samples were subjected to a comprehensive neoantigen identification approach encompassing genomics, transcriptomics and immunopeptidomics. Patients underwent leukapheresis for the manufacturing of monocyte-derived DCs loaded with neoantigens (Neo-mDCs) according to a four-day protocol. Neo-mDCs were injected intravenously following an intrapatient dose escalation scheme. Primary endpoint of the trial was safety. Secondary endpoints were feasibility, immunogenicity, and relapse-free survival. As a quality control, dendritic cells transfected with the mRNA-encoded neoantigen were analyzed by shotgun proteomics to validate expression of the mRNA-encoded neoantigen. Results. The vaccine was demonstrated to be feasible and safe. T cell responses were observed in 5 of 6 vaccinated patients and were dominated by CD8+ T cells, which could be detected ex vivo at high frequencies >1.5 years after the last dose. Furthermore, single cell analysis indicated that the CD8+ T cell responsive population was polyclonal and exhibited the near entire spectrum of T cell differentiation states, including a naïve-like state associated with long lasting memory. Additionally, mRNA-encoded neoantigen were detected by shotgun proteomics in four patients out of the six patients that were tested.