| 1. |
- Daniel, Michael G., et al.
(författare)
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Induction of human hemogenesis in adult fibroblasts by defined factors and hematopoietic coculture
- 2019
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 593:23, s. 3266-3287
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Tidskriftsartikel (refereegranskat)abstract
- Transcription factor (TF)-based reprogramming of somatic tissues holds great promise for regenerative medicine. Previously, we demonstrated that the TFs GATA2, GFI1B, and FOS convert mouse and human fibroblasts to hemogenic endothelial-like precursors that generate hematopoietic stem progenitor (HSPC)-like cells over time. This conversion is lacking in robustness both in yield and biological function. Herein, we show that inclusion of GFI1 to the reprogramming cocktail significantly expands the HSPC-like population. AFT024 coculture imparts functional potential to these cells and allows quantification of stem cell frequency. Altogether, we demonstrate an improved human hemogenic induction protocol that could provide a valuable human in vitro model of hematopoiesis for disease modeling and a platform for cell-based therapeutics. Database: Gene expression data are available in the Gene Expression Omnibus (GEO) database under the accession number GSE130361.
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| 2. |
- Gomes, Andreia M., et al.
(författare)
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Cooperative Transcription Factor Induction Mediates Hemogenic Reprogramming
- 2018
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247.
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Tidskriftsartikel (refereegranskat)abstract
- During development, hematopoietic stem and progenitor cells (HSPCs) arise from specialized endothelial cells by a process termed endothelial-to-hematopoietic transition (EHT). The genetic program driving human HSPC emergence remains largely unknown. We previously reported that the generation of hemogenic precursor cells from mouse fibroblasts recapitulates developmental hematopoiesis. Here, we demonstrate that human fibroblasts can be reprogrammed into hemogenic cells by the same transcription factors. Induced cells display dynamic EHT transcriptional programs, generate hematopoietic progeny, possess HSPC cell surface phenotype, and repopulate immunodeficient mice for 3 months. Mechanistically, GATA2 and GFI1B interact and co-occupy a cohort of targets. This cooperative binding is reflected by engagement of open enhancers and promoters, initiating silencing of fibroblast genes and activating the hemogenic program. However, GATA2 displays dominant and independent targeting activity during the early phases of reprogramming. These findings shed light on the processes controlling human HSC specification and support generation of reprogrammed HSCs for clinical applications. Gomes et al. show that specification of hemogenesis in human fibroblasts is mediated by cooperative transcription factor binding. GATA2 displays dominance, interacts with GFI1B, and recruits FOS to open chromatin, simultaneously silencing the fibroblast program and initiating an endothelial-to-hematopoietic transition to definitive hematopoiesis.
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| 3. |
- Marote, Ana, et al.
(författare)
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Cellular Aging Secretes : a Comparison of Bone-Marrow-Derived and Induced Mesenchymal Stem Cells and Their Secretome Over Long-Term Culture
- 2023
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Ingår i: Stem Cell Reviews and Reports. - : Springer Science and Business Media LLC. - 2629-3269 .- 2629-3277. ; 19:1, s. 248-263
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stem cells (MSCs) hold promising therapeutic potential in several clinical applications, mainly due to their paracrine activity. The implementation of future secretome-based therapeutic strategies requires the use of easily accessible MSCs sources that provide high numbers of cells with homogenous characteristics. MSCs obtained from induced pluripotent stem cells (iMSCs) have been put forward as an advantageous alternative to the gold-standard tissue sources, such as bone marrow (BM-MSCs). In this study, we aimed at comparing the secretome of BM-MSCs and iMSCs over long-term culture. For that, we performed a broad characterization of both sources regarding their identity, proteomic secretome analysis, as well as replicative senescence and associated phenotypes, including its effects on MSCs secretome composition and immunomodulatory action. Our results evidence a rejuvenated phenotype of iMSCs, which is translated into a superior proliferative capacity before the induction of replicative senescence. Despite this significant difference between iMSCs and BM-MSCs proliferation, both untargeted and targeted proteomic analysis revealed a similar secretome composition for both sources in pre-senescent and senescent states. These results suggest that shifting from the use of BM-MSCs to a more advantageous source, like iMSCs, may yield similar therapeutic effects as identified over the past years for this gold-standard MSC source. Graphical Abstract: [Figure not available: see fulltext.].
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| 4. |
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| 5. |
- Pereira, Andreia, et al.
(författare)
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A Low Complexity Sequential Resource Allocation for Panel-Based LIS Surfaces
- 2022
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Ingår i: 2022 IEEE 95th Vehicular Technology Conference - Spring, VTC 2022-Spring - Proceedings. - 1550-2252. - 9781665482431 ; 2022-June
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Konferensbidrag (refereegranskat)abstract
- Large intelligent surfaces (LISs) is an evolution of massive MIMO systems allowing for huge capacity gains. To reduce implementation complexity, it is convenient to implement the LIS using panels that are either activated or deactivated, and associated to terminals according to their propagation characteristics to the panels. The associated spatial resource allocation to maximise the terminals', as well as the overall, bit rates can lead to complex optimisation problems.In this paper we consider resource allocation for panel-based LIS surfaces. We present an iterative sequential algorithm for determining the set of active panels and the respective panel-terminal association for the maximisation of the minimum terminal rate. Our algorithm is decentralised and has low complexity. Moreover, it approaches the performance of much more complex, quasi-optimum algorithms.
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| 6. |
- Pereira, Andreia, et al.
(författare)
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Deployment Strategies for Large Intelligent Surfaces
- 2022
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Ingår i: IEEE Access. - 2169-3536. ; 10, s. 61753-61768
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Tidskriftsartikel (refereegranskat)abstract
- Beyond 5G communication systems must be able to meet the requirements imposed by the ever-increasing demand in capacity, while guaranteeing robustness, reliability, low latency, security, as well as spectral and power efficiencies. Large intelligent surfaces (LIS) as an evolution of massive MIMO have drawn considerable attention among researchers, being already considered as one of the key technologies to be included in beyond 5G communication systems. Due to the massive number of antennas, it also brings several challenges namely in terms of computational complexity. In this paper, we intend to provide guidelines for the LIS practical implementation and configuration by specifying system parameters and their consequent relationship for a panel-based LIS. In particular, the interplay between the number of baseband outputs per square metre, the fraction of activated area, the panel size and terminal density is summarised by an empirical law under the assumption that all terminals experience reasonable quality of service. Furthermore, performance results show that, in general, moderate panel sizes offer the best rates, highlighting that there is no need to activate a large fraction of LIS to provide an acceptable minimum terminal rate. However, such fractions may require more baseband outputs per panel, leading to a higher number of baseband outputs per square metre, translating into higher implementation complexity. Finally, it is observed that the implicit rate loss of using sparse static panel deployments instead of contiguous panel deployments that are dynamically activated/deactivated is not so significant, omitting the complexity involved in managing the set of activated panels.
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| 7. |
- Pereira, Andreia, et al.
(författare)
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On the Complexity Requirements of a Panel-Based Large Intelligent Surface
- 2020
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Ingår i: 2020 IEEE Global Communications Conference, GLOBECOM 2020 - Proceedings. - 9781728182988 ; 2020-January
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Konferensbidrag (refereegranskat)abstract
- A Large Intelligent Surface (LIS) is a recently proposed concept, especially suitable for high speed indoor communications and industrial internet of things (IoT) applications. Basing the LIS on smaller panels has clear advantages in terms of flexibility and mass production of its elements. In this paper we consider a panel-based LIS and we study the interplay of the panel size, the number of baseband outputs per square meter of deployed surface, the total activated surface area, the number of baseband outputs per panel, the terminal density and the ensuing minimum terminal rate. Our performance results show that it is desirable to employ smaller panels when the terminal density increases, but this means more outputs per m2, and higher overall LIS implementation complexity. It was observed that we can surpass such increase by working with higher fractions of the LIS area. Furthermore, we present an empirical equation stating the number of outputs per panel needed to ensure that all terminals are reasonably served. These results are useful for the LIS design in practical scenarios.
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| 8. |
- Pereira, Andreia, et al.
(författare)
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The Impact of Terminal Mobility on the Performance of a Panel-Based Large Intelligent Surface
- 2020
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Ingår i: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 569-573
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Konferensbidrag (refereegranskat)abstract
- A Large Intelligent Surface (LIS) is a recently pro-posed concept that relies on the integration of a vast number of antenna-elements over an entire surface able to transmit and/or receive information, especially suitable for high speed indoor communications and massive internet of things (IoT) applications. In this paper, we study the impact of terminal mobility on the performance of a panel-based LIS, considering different resource allocation approaches (including panel selection and/or panel-terminal association) and small panel areas. Such configuration represents a clear advantage in terms of flexibility, together with the fact that, from an economy of scale perspective, the production of this type of configuration choosing smaller areas seems more foreseeable.Our performance results show that there is no need to have a contagious distribution of panels, instead they can be physically separated according to a given distribution. It is also observed that, keeping a regularly fixed or predefined panel scheme, leading only to panel-terminal association, are able to fight against the unpredictability of terminal movements and overcome the computational complexity imposed by the optimum approach (that includes both panel selection and terminal-panel allocation stages), presenting maximum rate losses of 16-30%.
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| 9. |
- Rosa, Fábio F., et al.
(författare)
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Direct reprogramming of fibroblasts into antigen-presenting dendritic cells
- 2018
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Ingår i: Science Immunology. - : American Association for the Advancement of Science (AAAS). - 2470-9468. ; 3:30
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Tidskriftsartikel (refereegranskat)abstract
- Ectopic expression of transcription factors has been used to reprogram differentiated somatic cells toward pluripotency or to directly reprogram them to other somatic cell lineages. This concept has been explored in the context of regenerative medicine. Here, we set out to generate dendritic cells (DCs) capable of presenting antigens from mouse and human fibroblasts. By screening combinations of 18 transcription factors that are expressed in DCs, we have identified PU.1, IRF8, and BATF3 transcription factors as being sufficient to reprogram both mouse and human fibroblasts to induced DCs (iDCs). iDCs acquire a conventional DC type 1-like transcriptional program, with features of interferon-induced maturation. iDCs secrete inflammatory cytokines and have the ability to engulf, process, and present antigens to T cells. Furthermore, we demonstrate that murine iDCs generated here were able to cross-present antigens to CD8+ T cells. Our reprogramming system should facilitate better understanding of DC specification programs and serve as a platform for the development of patient-specific DCs for immunotherapy.
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| 10. |
- Silvério-Alves, Rita, et al.
(författare)
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Hemogenic Reprogramming of Human Fibroblasts by Enforced Expression of Transcription Factors
- 2019
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Ingår i: Journal of visualized experiments : JoVE. - : MyJove Corporation. - 1940-087X. ; :153
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Tidskriftsartikel (refereegranskat)abstract
- The cellular and molecular mechanisms underlying specification of human hematopoietic stem cells (HSCs) remain elusive. Strategies to recapitulate human HSC emergence in vitro are required to overcome limitations in studying this complex developmental process. Here, we describe a protocol to generate hematopoietic stem and progenitor-like cells from human dermal fibroblasts employing a direct cell reprogramming approach. These cells transit through a hemogenic intermediate cell-type, resembling the endothelial-to-hematopoietic transition (EHT) characteristic of HSC specification. Fibroblasts were reprogrammed to hemogenic cells via transduction with GATA2, GFI1B and FOS transcription factors. This combination of three factors induced morphological changes, expression of hemogenic and hematopoietic markers and dynamic EHT transcriptional programs. Reprogrammed cells generate hematopoietic progeny and repopulate immunodeficient mice for three months. This protocol can be adapted towards the mechanistic dissection of the human EHT process as exemplified here by defining GATA2 targets during the early phases of reprogramming. Thus, human hemogenic reprogramming provides a simple and tractable approach to identify novel markers and regulators of human HSC emergence. In the future, faithful induction of hemogenic fate in fibroblasts may lead to the generation of patient-specific HSCs for transplantation.
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