Age-related pathways in cardiac regeneration : a role for lncRNAs?

Copyright © 2021 Santos, Correia, Nóbrega-Pereira and Bernardes de Jesus. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Aging imposes a barrier for tissue regeneration. In the heart, aging leads to a severe rearrangement of the cardiac structure and function and to a subsequent increased risk of heart failure. An intricate network of distinct pathways contributes to age-related alterations during healthy heart aging and account for a higher susceptibility of heart disease. Our understanding of the systemic aging process has already led to the design of anti-aging strategies or to the adoption of protective interventions. Nevertheless, our understanding of the molecular determinants operating during cardiac aging or repair remains limited. Here, we will summarize the molecular and physiological alterations that occur during aging of the heart, highlighting the potential role for long non-coding RNAs (lncRNAs) as novel and valuable targets in cardiac regeneration/repair.This work was supported by Fundação para a Ciência e Tecnologia (FCT; ERA-CVD 2018 / 3599-PPCDT - ERA-CVD/0001/2018 - INNOVATION).info:eu-repo/semantics/publishedVersio

Strategies for cancer immunotherapy using induced pluripotency stem cells-based vaccines

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Despite improvements in cancer therapy, metastatic solid tumors remain largely incurable. Immunotherapy has emerged as a pioneering and promising approach for cancer therapy and management, and in particular intended for advanced tumors unresponsive to current therapeutics. In cancer immunotherapy, components of the immune system are exploited to eliminate cancer cells and treat patients. The recent clinical successes of immune checkpoint blockade and chimeric antigen receptor T cell therapies represent a turning point in cancer treatment. Despite their potential success, current approaches depend on efficient tumor antigen presentation which are often inaccessible, and most tumors turn refractory to current immunotherapy. Patient-derived induced pluripotent stem cells (iPSCs) have been shown to share several characteristics with cancer (stem) cells (CSCs), eliciting a specific anti-tumoral response when injected in rodent cancer models. Indeed, artificial cellular reprogramming has been widely compared to the biogenesis of CSCs. Here, we will discuss the state-of-the-art on the potential implication of cellular reprogramming and iPSCs for the design of patient-specific immunotherapeutic strategies, debating the similarities between iPSCs and cancer cells and introducing potential strategies that could enhance the efficiency and therapeutic potential of iPSCs-based cancer vaccines.This research was funded by Fundação para a Ciência e Tecnologia (FCT), and FEDER, LISBOA-01-0145-FEDER-028534, project co-funded by FEDER, through POR Lisboa 2020—Programa Operacional Regional de Lisboa, PORTUGAL 2020, FEDER—Fundo Europeu de Desenvolvimento Regional through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, by Portuguese funds through FCT, in the framework of the project UIDB/04501/2020 to iBiMED and by the European Commission (ERA-CVD Joint Call 2018, grant#INNOVATION) through FCT and the Portuguese Ministry of Health, through the Directorate General of Health (DGS).info:eu-repo/semantics/publishedVersio

The RNA Polymerase II Factor RPAP1 Is Critical for Mediator-Driven Transcription and Cell Identity

The RNA polymerase II-associated protein 1 (RPAP1) is conserved across metazoa and required for stem cell differentiation in plants; however, very little is known about its mechanism of action or its role in mammalian cells. Here, we report that RPAP1 is essential for the expression of cell identity genes and for cell viability. Depletion of RPAP1 triggers cell de-differentiation, facilitates reprogramming toward pluripotency, and impairs differentiation. Mechanistically, we show that RPAP1 is essential for the interaction between RNA polymerase II (RNA Pol II) and Mediator, as well as for the recruitment of important regulators, such as the Mediator-specific RNA Pol II factor Gdown1 and the C-terminal domain (CTD) phosphatase RPAP2. In agreement, depletion of RPAP1 diminishes the loading of total and Ser5-phosphorylated RNA Pol II on many genes, with super-enhancer-driven genes among the most significantly downregulated. We conclude that Mediator/RPAP1/RNA Pol II is an ancient module, conserved from plants to mammals, critical for establishing and maintaining cell identity.We are grateful to Elisa Varela for assistance with morula and blastocyst fixa- tion. Work in the laboratory of M.S. is funded by the CNIO and the IRB and by grants from the Spanish Ministry of Economy co-funded by the European Regional Development Fund (ERDF) (SAF2013-48256-R), the European Research Co uncil (ERC-2014-AdG/66 9622), the Region al Government of Ma- drid co-funded by the Euro pean Social Fund (ReCaRe project), the Euro pean Union (RISK-IR project), the Botin Foundation and Banco Santander (Santander Universities Glo bal Division), the Ramon Areces Found ation, and the AXA Foundation. S.R. was funded by a contract from the Ramon y Cajal Program(RYC-2011-09242) and by the Spanish Ministry of Economy co- funded by the ERDF (SAF2013-49147- P and SAF2016-80874-PS

Global hyperactivation of enhancers stabilizes human and mouse naïve pluripotency through inhibition of CDK8/19 Mediator kinases

Pluripotent stem cells (PSCs) transition between cell states in vitro and reflect developmental changes in the early embryo. PSCs can be stabilized in the naïve state by blocking extracellular differentiation stimuli, particularly FGF-MEK signaling. Here, we report that multiple features of the naïve state in human and mouse PSCs can be recapitulated without affecting FGF-MEK-signaling or global DNA methylation. Mechanistically, chemical inhibition of CDK8 and CDK19 kinases removes their ability to repress the Mediator complex at enhancers. Thus CDK8/19 inhibition increases Mediator-driven recruitment of RNA Pol II to promoters and enhancers. This efficiently stabilizes the naïve transcriptional program and confers resistance to enhancer perturbation by BRD4 inhibition. Moreover, naïve pluripotency during embryonic development coincides with a reduction in CDK8/19. We conclude that global hyperactivation of enhancers drives naïve pluripotency, and this can be achieved in vitro by inhibiting CDK8/19 kinase activity. These principles may apply to other contexts of cellular plasticity

Cellular and molecular mechanisms controlling the migration of telencephalic interneurons : a role for postmitotic Nkx2-1 in neuronal migration

The homeodomain transcription factor Nkx2-1 plays fundamental roles in the development of the ventral subpallium. As for the majority of NK-2 class of transcription factors, Nkx2-1 function mainly in controlling cell-fate decisions in progenitor cells, such as interpreting Sonic Hedgehog (Shh) graded signalling in early patterning events and conferring subtype-specific properties to medial ganglionic eminence (MGE) and preoptic area (POA) precursors. During development, the MGE is simultaneously the source for several telencephalic cell types, such as cortical and striatal interneurons, but interestingly, the expression of Nkx2-1 is only maintained in the striatal population. This evidence suggests a possible function for Nkx2-1 in controlling the migration and/or differentiation of postmitotic striatal interneurons; however the contribution of this transcription factor at this level has not been characterized. Using experimental manipulations and mouse genetics, we demonstrated a new postmitotic function for the cell-fate determinant Nkx2-1 in controlling neuronal migration in the developing telencephalon. Downregulation of Nkx2-1 expression in MGE-derived postmitotic cells is necessary for the migration of interneurons to the cortex, whereas maintenance of Nkx2-1 expression is required for interneuron migration to the striatum. The sorting of MGE-derived cortical and striatal interneurons is mediated by the differential expression of receptors for the class 3 semaphorins, neuropilins, which are expressed only by cortical migrating interneurons in order to prevent their accumulation in the developing striatum. We showed that Nkx2-1 regulates the segregation of MGE-derived interneurons by controlling the neuropilin/semaphorin interactions; Nkx2-1 overexpression leaves migrating interneurons insensible to a source of Sema3A/3F and reduces the expression of Neuropilin-2 (Nrp2), the binding receptor for Sema3F. Furthermore, Nkx2-1 exerts this role by direct binding to Nrp2 regulatory elements in MGE cells and interaction with this sequence is sufficient to repress transcription in vitro through a mechanism that requires the Nkx2-1 homeodomain (HD) motif. These results demonstrate that Nkx2-1 postmitotic expression controls the migration of MGE-derived interneurons by direct repression of the Nrp2 guidance receptor, a transcriptional strategy of guidance selectivity operating in many other migrating neurons. Furthermore, we provide evidence that, apart from the neuropilin/semaphorin interactions, the precise migration of interneurons to the developing striatum is regulated by additional guidance systems. We demonstrated that a population of MGE-derived interneurons co-expresses Nkx2- and ErbB4, and relies in an ErbB4-dependent signalling to specifically accumulate in the striatum. Furthermore, Nkx2-1-expressing interneurons are actively prevented from invading the developing cortex by a yet unidentified chemorepulsive activity and we believe that the cooperative action of these signalling systems will ultimately determine the directionality of striatal migrating interneurons. In addition, these results suggest that postmitotic Nkx2-1 is a fundamental factor in conferring guidance specificity to striatal migrating interneurons and open the possibility for additional downstream target effector genes.O factor de transcrição Nkx2-1 desempenha funções fundamentais durante o desenvolvimento do telencéfalo ventral. Como a maior parte dos factores de transcrição pertencentes à classe NK-2, o Nkx2-1 controla processos de decisão e especificação celular em células progenitoras. Em particular, é responsável por interpretar a via de sinalização do morfogénio “Sonic Hedgehog” (Shh) e pela indução de várias propriedades que conferem identidade às células progenitoras da eminência ganglionar medial (“MGE”) e da área pré-óptica anterior (“POA”). Durante o desenvolvimento, as células progenitoras da eminência ganglionar medial originam simultaneamente diversos tipos de neurónios, como os interneurónios do córtex e do estriado e, curiosamente, a expressão deste factor de transcrição mantém-se apenas na população diferenciada de interneurónios do estriado. Esta evidência sugere que o Nkx2-1 poderá controlar a migração ou diferenciação dos interneurónios do estriado; contudo, a contribuição deste factor de transcrição para estes processos não estava caracterizada. Neste estudo identificámos uma nova função para o factor de transcrição Nkx2-1 no controlo da migração de interneurónios durante o desenvolvimento embrionário do telencéfalo. A realização de estudos funcionais e o uso de murganhos transgénicos permitiu-nos demonstrar que os interneurónios corticais necessitam de deixar de expressar Nkx2-1 para migrarem para o córtex e, por outro lado, a migração dos interneurónios do estriado requer a expressão contínua deste factor de transcrição. A segregação destas duas populações de interneurónios originados na “MGE” tinha sido previamente atribuída à expressão diferencial de receptores para as semaforinas da classe 3, moléculas repulsivas existentes no estriado. Estes receptores, as neuropilinas, expressa-se apenas pelos interneurónios corticais em migração e previnem a sua entrada no estriado. Os nossos resultados permitiram-nos inferir que Nkx2-1 regula a segregação destas populações de interneurónios através do controlo das interacções neuropilina/semaforina; a sobre-expressão de Nkx2-1 tornou os interneurónios derivados da MGE insensíveis a uma fonte externa de semaforinas e reduziu a expressão de Neuropilina-2 (Nrp2), o receptor de ligação para a semaforina 3F. Nkx2-1 exerce esta função por união directa a elementos reguladores do gene de Nrp2 em células da “MGE” e a interacção com esta sequência é suficiente para reprimir a transcrição in vitro por um mecanismo que envolve o homeodomínio (HD) de Nkx2-1. Estes resultados demonstram que Nkx2-1 controla a migração de interneurónios provenientes da “MGE” através de repressão directa do receptor Nrp2, uma estratégia de controlo de direcção de movimento adoptada por vários tipos de neurónios em migração. O trabalho apresentado nesta dissertação sugere que, para além das interacções neuropilina/semaforina, a migração de interneurónios do estriado é regulada por outros sistemas de sinalização. Observámos que uma população de interneurónios originados na “MGE” expressa o factor de transcrição Nkx2-1 e o receptor ErbB4, e que estes interneurónios usam uma via de sinalização dependente de ErbB4 para migrar para o estriado. Estudos funcionais indicaram também que a sobre-expressão de Nkx2-1 incapacita os interneurónios de invadirem o córtex, possivelmente devido à presença de uma actividade repulsiva nesta região cuja identidade é desconhecida. Estes resultados permitem concluir que a direcção de migração dos interneurónios do estriado é regulada pela acção conjunta de várias vias de sinalização e que o factor de transcrição Nkx2-1 desempenha um papel fundamental no movimento dos interneurónios do estriado

New Insights into the Role of Epithelial–Mesenchymal Transition during Aging

Epithelial⁻mesenchymal transition (EMT) is a cellular process by which differentiated epithelial cells undergo a phenotypic conversion to a mesenchymal nature. The EMT has been increasingly recognized as an essential process for tissue fibrogenesis during disease and normal aging. Higher levels of EMT proteins in aged tissues support the involvement of EMT as a possible cause and/or consequence of the aging process. Here, we will highlight the existing understanding of EMT supporting the phenotypical alterations that occur during normal aging or pathogenesis, covering the impact of EMT deregulation in tissue homeostasis and stem cell function

Origin and molecular specification of globus pallidus neurons.

International audienceThe mechanisms controlling the assembly of brain nuclei are poorly understood. In the forebrain, it is typically assumed that the formation of nuclei follows a similar sequence of events that in the cortex. In this structure, projection neurons are generated sequentially from common progenitor cells and migrate radially to reach their final destination, whereas interneurons are generated remotely and arrive to the cortex through tangential migration. Using the globus pallidus as a model to study the formation of forebrain nuclei, we found that the development of this basal ganglia structure involves the generation of several distinct classes of projection neurons from relatively distant progenitor pools, which then assemble together through tangential migration. Our results thus suggest that tangential migration in the forebrain is not limited to interneurons, as previously thought, but also involves projection neurons and reveal that the assembly of forebrain nuclei is more complex than previously anticipated

Metabolic Determinants in Cardiomyocyte Function and Heart Regenerative Strategies

Heart disease is the leading cause of mortality in developed countries. The associated pathology is characterized by a loss of cardiomyocytes that leads, eventually, to heart failure. In this context, several cardiac regenerative strategies have been developed, but they still lack clinical effectiveness. The mammalian neonatal heart is capable of substantial regeneration following injury, but this capacity is lost at postnatal stages when cardiomyocytes become terminally differentiated and transit to the fetal metabolic switch. Cardiomyocytes are metabolically versatile cells capable of using an array of fuel sources, and the metabolism of cardiomyocytes suffers extended reprogramming after injury. Apart from energetic sources, metabolites are emerging regulators of epigenetic programs driving cell pluripotency and differentiation. Thus, understanding the metabolic determinants that regulate cardiomyocyte maturation and function is key for unlocking future metabolic interventions for cardiac regeneration. In this review, we will discuss the emerging role of metabolism and nutrient signaling in cardiomyocyte function and repair, as well as whether exploiting this axis could potentiate current cellular regenerative strategies for the mammalian heart

Low-Density Lipoprotein Uptake Inhibits the Activation and Antitumor Functions of Human Vγ9Vδ2 T Cells

Abstract Vγ9Vδ2 T cells, the main subset of γδ T lymphocytes in human peripheral blood, are endowed with antitumor functions such as cytotoxicity and IFNγ production. These functions are triggered upon T-cell receptor–dependent activation by non-peptidic prenyl pyrophosphates (“phosphoantigens”) that are selective agonists of Vγ9Vδ2 T cells, and which have been evaluated in clinical studies. Because phosphoantigens have shown interindividual variation in Vγ9Vδ2 T-cell activities, we asked whether metabolic resources, namely lipids such as cholesterol, could affect phosphoantigen-mediated Vγ9Vδ2 T-cell activation and function. We show here that Vγ9Vδ2 T cells express the LDL receptor upon activation and take up LDL cholesterol. Resulting changes, such as decreased mitochondrial mass and reduced ATP production, correlate with downregulation of Vγ9Vδ2 T-cell activation and functionality. In particular, the expression of IFNγ, NKG2D, and DNAM-1 were reduced upon LDL cholesterol treatment of phosphoantigen-expanded Vγ9Vδ2 T cells. As a result, their capacity to target breast cancer cells was compromised both in vitro and in an in vivo xenograft mouse model. Thus, this study describes the role of LDL cholesterol as an inhibitor of the antitumor functions of phosphoantigen-activated Vγ9Vδ2 T cells. Our observations have implications for therapeutic applications dependent on Vγ9Vδ2 T cells. Cancer Immunol Res; 6(4); 448–57. ©2018 AACR.</jats:p