RESUMO
Our digital age is characterized by both a generalized access to data and an increased call for participation of the public and other stakeholders and communities in policy design and decision-making. This context raises new challenges for political decision-makers and analysts in providing these actors with new means and moral duties for decision support, including in the area of environmental policy. The concept of "policy analytics" was introduced in 2013 as an attempt to develop a framework, tools, and methods to address these challenges. This conceptual initiative prompted numerous research teams to develop empirical applications of this framework and to reflect on their own decision-support practice at the science-policy interface in various environmental domains around the world. During a workshop in Paris in 2018, participants shared and discussed their experiences of these applications and practices. In this paper, we present and analyze a set of applications to identify a series of key properties that underpin a policy analytics approach, in order to provide the conceptual foundation for policy analytics to address current policy design and decision-making challenges. The induced properties are demand-orientedness, performativity, normative transparency, and data meaningfulness. We show how these properties materialized through these six case studies, and we explain why we consider them key to effective policy analytics applications, particularly in environmental policy design and decision-making on environmental issues. This clarification of the policy analytics concept eventually enables us to highlight research frontiers to further improve the concept.
Assuntos
Conservação dos Recursos Naturais , Formulação de Políticas , Humanos , PolíticasRESUMO
The physiological functions and cellular signaling of Class II phosphoinositide 3-kinases (PI3Ks) remain largely unknown. Platelets express two Class II PI3Ks: PI3KC2α and PI3KC2ß. PI3KC2α deficiency was recently reported to cause disruption of the internal membrane reserve structure of platelets (open canalicular system, OCS) that results in dysregulated platelet adhesion and impaired arterial thrombosis in vivo. Notably, these effects on platelets occurred despite normal agonist-induced 3-phosphorylated phosphoinositide (3-PPI) production and cellular activation in PI3KC2α-deficient platelets. However, the potential compensatory actions of PI3KC2ß in platelets have not yet been investigated. Here, we report the first mice deficient in both PI3KC2α and PI3KC2ß (no Class II PI3Ks in platelets) and reveal a nonredundant role for PI3KC2α in mouse platelet structure and function. Specifically, we show that the disrupted OCS and impaired thrombus stability observed in PI3KC2α-deficient platelets does not occur in PI3KC2ß-deficient platelets and is not exaggerated in platelets taken from mice deficient in both enzymes. Furthermore, detailed examination of 3-PPI production in platelets from this series of mice revealed no changes in either unactivated or activated platelets, including those with a complete lack of Class II PI3Ks. These findings indicate a nonredundant role for PI3KC2α in regulating platelet structure and function, and suggest that Class II PI3Ks do not significantly contribute to the acute agonist-induced production of 3-PPIs in these cells.
Assuntos
Plaquetas/metabolismo , Classe II de Fosfatidilinositol 3-Quinases/deficiência , Trombose/sangue , Trombose/genética , Animais , Plaquetas/ultraestrutura , Classe II de Fosfatidilinositol 3-Quinases/genética , Classe II de Fosfatidilinositol 3-Quinases/metabolismo , Classe III de Fosfatidilinositol 3-Quinases/genética , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica , Camundongos , Camundongos Knockout , Adesividade Plaquetária , Contagem de Plaquetas , Testes de Função PlaquetáriaRESUMO
PI3KC2α is a broadly expressed lipid kinase with critical functions during embryonic development but poorly defined roles in adult physiology. Here we utilize multiple mouse genetic models to uncover a role for PI3KC2α in regulating the internal membrane reserve structure of megakaryocytes (demarcation membrane system) and platelets (open canalicular system) that results in dysregulated platelet adhesion under haemodynamic shear stress. Structural alterations in the platelet internal membrane lead to enhanced membrane tether formation that is associated with accelerated, yet highly unstable, thrombus formation in vitro and in vivo. Notably, agonist-induced 3-phosphorylated phosphoinositide production and cellular activation are normal in PI3KC2α-deficient platelets. These findings demonstrate an important role for PI3KC2α in regulating shear-dependent platelet adhesion via regulation of membrane structure, rather than acute signalling. These studies provide a link between the open canalicular system and platelet adhesive function that has relevance to the primary haemostatic and prothrombotic function of platelets.
Assuntos
Plaquetas/metabolismo , Regulação da Expressão Gênica , Fosfatidilinositol 3-Quinases/metabolismo , Estresse Mecânico , Alelos , Animais , Transplante de Medula Óssea , Adesão Celular , Cruzamentos Genéticos , Genótipo , Hemostasia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Transmissão , Mutação , Perfusão , Fosforilação , Adesividade Plaquetária , Agregação Plaquetária , Resistência ao Cisalhamento , Transdução de Sinais , Trombose/genética , Trombose/metabolismoRESUMO
Microglial cells are the resident macrophages of the central nervous system and participate in both innate and adaptive immune responses but can also lead to exacerbation of neurodegenerative pathologies after viral infections. Microglia in the outer layers of the retina and the subretinal space are thought to be involved in retinal diseases where low-grade chronic inflammation and oxidative stress play a role. This study investigated the effect of systemic infection with murine cytomegalovirus on the distribution and dynamics of retinal microglia cells. Systemic infection with murine cytomegalovirus elicited a significant increase in the number of microglia in the subretinal space and an accumulation of iris macrophages, along with morphological signs of activation. Interferon γ (IFN-γ)-deficient mice failed to induce changes in microglia distribution. Bone marrow chimera experiments confirmed that microglial cells in the subretinal space were not recruited from the circulating monocyte pool, but rather represented an accumulation of resident microglial cells from within the retina. Our results demonstrate that a systemic viral infection can lead to IFN-γ-mediated accumulation of microglia into the outer retinal layers and offer proof of concept that systemic viral infections alter the ocular microenvironment and therefore, may influence the course of diseases such as macular degeneration, diabetic retinopathy, or autoimmune uveitis, where low-grade inflammation is implicated.
Assuntos
Movimento Celular , Infecções por Citomegalovirus/patologia , Interferon gama/metabolismo , Microglia/patologia , Muromegalovirus/fisiologia , Retina/patologia , Retina/virologia , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Contagem de Células , Movimento Celular/efeitos dos fármacos , Infecções por Citomegalovirus/virologia , Feminino , Citometria de Fluxo , Iris/patologia , Iris/virologia , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Macrófagos/virologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Microglia/efeitos dos fármacos , Microglia/virologia , Muromegalovirus/efeitos dos fármacos , Fator 88 de Diferenciação Mieloide/metabolismo , Oligodesoxirribonucleotídeos/administração & dosagem , Oligodesoxirribonucleotídeos/farmacologia , Retina/efeitos dos fármacos , Segmento Externo das Células Fotorreceptoras da Retina/efeitos dos fármacos , Segmento Externo das Células Fotorreceptoras da Retina/patologia , Segmento Externo das Células Fotorreceptoras da Retina/virologiaRESUMO
Cytomegalovirus (CMV) reactivation in the retina of immunocompromized patients is a cause of significant morbidity as it can lead to blindness. The adaptive immune response is critical in controlling murine CMV (MCMV) infection in MCMV-susceptible mouse strains. CD8(+) T cells limit systemic viral replication in the acute phase of infection and are essential to contain latent virus. In this study, we provide the first evaluation of the kinetics of anti-viral T-cell responses after subretinal infection with MCMV. The acute response was characterized by a rapid expansion phase, with infiltration of CD8(+) T cells into the infected retina, followed by a contraction phase. MCMV-specific T cells displayed biphasic kinetics with a first peak at day 12 and contraction by day 18 followed by sustained recruitment of these cells into the retina at later time points post-infection. MCMV-specific CD8(+) T cells were also observed in the draining cervical lymph nodes and the spleen. Presentation of viral epitopes and activation of CD8(+) T cells was widespread and could be detected in the spleen and the draining lymph nodes, but not in the retina or iris. Moreover, after intraocular infection, antigen-specific cytotoxic activity was detectable and exhibited kinetics equivalent to those observed after intraperitoneal infection with the same viral dose. These data provide novel insights of how and where immune responses are initiated when viral antigen is present in the subretinal space.
Assuntos
Imunidade Adaptativa , Linfócitos T CD8-Positivos/imunologia , Retinite por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Retina/imunologia , Animais , Apresentação de Antígeno , Linfócitos T CD8-Positivos/virologia , Processos de Crescimento Celular , Movimento Celular , Células Cultivadas , Retinite por Citomegalovirus/virologia , Modelos Animais de Doenças , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/metabolismo , Humanos , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Retina/virologia , Proteínas Virais/imunologia , Proteínas Virais/metabolismoRESUMO
PURPOSE: To develop a technique by which murine cytomegalovirus (MCMV) infection can be confirmed and monitored in vivo in various ocular compartments and to investigate the dynamics and time course of primary ocular CMV infection. METHODS: The ability of recombinant MCMV-expressing enhanced green fluorescent protein (eGFP) to serve as a tool to monitor the in vivo dynamics of experimental intraocular CMV infection was examined. Immunocompetent BALB/c mice were infected subretinally with eGFP-MCMV. Confocal scanning laser ophthalmoscopy (SLO) was used to visualize viral spread in vivo on sequential days after infection. Eyes were processed for histology and immunofluorescence microscopy to confirm viral infection and replication by means of GFP signal. RESULTS: Retina was readily permissive to primary infection with eGFP-mCMV, and fluorescent signal was detected by SLO 24 hours after subretinal injection, with scattered foci around the posterior pole of the retina. GFP levels in the retina reached a maximum on day 6. Signal in the iris developed from day 4 and lasted until day 25. Examinations of retinal and iris tissue wholemounts by immunofluorescence revealed signal localized to the outer retina, iris stroma, and anterior lens capsule. CONCLUSIONS: The ability to noninvasively monitor infectious agents in the eye may improve current knowledge of the course and pathogenesis of intraocular infections and could lead to further clarification of the mechanisms by which the immune system responds to intraocular pathogens.
Assuntos
Retinite por Citomegalovirus/diagnóstico , Proteínas de Fluorescência Verde , Infecções por Herpesviridae/diagnóstico , Microscopia Confocal , Muromegalovirus/fisiologia , Animais , Retinite por Citomegalovirus/virologia , Modelos Animais de Doenças , Feminino , Angiofluoresceinografia , Técnica Indireta de Fluorescência para Anticorpo , Infecções por Herpesviridae/virologia , Iris/virologia , Cápsula do Cristalino/virologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência , Retina/virologia , Replicação Viral/fisiologiaRESUMO
BACKGROUND: Giant platelets and thrombocytopenia are invariable defects in the Bernard-Soulier syndrome caused by deficiency of the GPIb-V-IX complex, a receptor for von Willebrand factor supporting platelet adhesion to the damaged arterial wall. Various properties of this receptor may be considered potential determinants of the macrothrombocytopenia. DESIGN AND METHODS: To explore the underlying mechanisms of the disease, megakaryopoiesis was studied in a mouse model deficient in GPIbbeta. Megakaryocytes were initially characterized in situ in the bone marrow of adult mice, after which their capacity to differentiate into proplatelet-bearing cells was evaluated in cultured fetal liver cells. RESULTS: The number of megakaryocyte progenitors, their differentiation and progressive maturation into distinct classes and their level of endoreplication were normal in GPIbbeta(-/-) bone marrow. However, the more mature cells exhibited ultrastructural anomalies with a thicker peripheral zone and a less well developed demarcation membrane system. GPIbbeta(-/-) megakaryocytes could be differentiated in culture from Lin(-) fetal liver cells in normal amounts but the proportion of cells able to extend proplatelets was decreased by 41%. Moreover, the GPIbbeta(-/-) cells extending proplatelets displayed an abnormal morphology characterized by fewer pseudopodial extensions with thicker shaft sections and an increased diameter of the terminal coiled elements. GPIbbeta(-/-) released platelets were larger but retained a typical discoid shape. Proplatelet formation was similarly affected in bone marrow explants from adult mice examined by videomicroscopy. The marginal microtubular ring contained twice as many tubulin fibers in GPIbbeta(-/-) proplatelet buds in cultured and circulating platelets. CONCLUSIONS: Altogether, these findings point to a role of the GPIb-V-IX complex intrinsic to megakaryocytes at the stage of proplatelet formation and suggest a functional link with the underlying microtubular cytoskeleton in platelet biogenesis.