Optical induction of presynaptic plasticity using synaptoPAC

A major topic in neuroscience is the cellular basis of learning and memory. Memories are stored in neuronal engrams, co-active neurons that are synaptically connected. Synaptic plasticity, due to its ability to alter synaptic weight within a neuronal network, has been hypothesised to play a role in information storage. Despite decades of research, little is known about presynaptic plasticity, a form of plasticity defined as activity-dependent modulation of neurotransmitter release. Remarkably, the specific contribution of presynaptic plasticity to behaviour is unknown, which is in part due to a lack of methods that allow its specific in vivo manipulation. In order to overcome these limitations, we have engineered and characterised synaptoPAC, a novel optogenetic tool that allows induction of presynaptic plasticity. SynaptoPAC is designed as the fusion of the photoactivated adenylyl cyclase bPAC to the presynaptic vesicle protein synaptophysin. The design allows an increase of cyclic adenosine monophosphate (cAMP) in presynaptic terminals using light. Elevated presynaptic cAMP was previously demonstrated to cause an increase in release probability and induce presynaptic potentiation at specific synapses. With immunofluorescence imaging of cultured neurons we demonstrated that synaptoPAC is enriched at presynaptic terminals, as indicated by its co-localization with the synaptic vesicle protein VGLUT1. We verified the light-driven increase of cAMP by synaptoPAC by performing electrophysiological whole-cell recordings of ND7/23 cells co-expressing synaptoPAC and the cAMP-gated channel SthK. In whole-cell recordings of autaptic hippocampal cultures expressing synaptoPAC, we observed an increase of neurotransmitter release during light stimulation as well as concomitant changes in short-term plasticity properties in granule cells, but not in other cell types. In vivo expression of synaptoPAC in the dentate gyrus of the hippocampus and subsequent field excitatory postsynaptic potential (fEPSP) recordings in acute brain slices enabled us to demonstrate optically induced long-term plasticity in mossy fibre-CA3 synapses. Interestingly, activation of the tool did not cause increase in the amplitude of Schaffer collateral-CA1 synapse fEPSPs in in vitro recordings, indicating that synaptoPAC can induce potentiation only in synapses that are already predisposed to presynaptic plasticity. Further investigations in hippocampal slice preparations of short-term plasticity in mossy fibre synapses confirmed the presynaptic nature of the optical potentiation. Our results establish synaptoPAC as a valid tool that can be used to answer questions regarding the role of presynaptic plasticity in the brain and increase understanding of diseases characterised by impairments of this kind of plasticity.Ein wichtiges Thema der Neurowissenschaften ist die zelluläre Grundlage von Lernen und Gedächtnis. Gedächtnisspuren werden in neuronalen Engrammen gespeichert, dies sind koaktive Neurone, welche synaptisch miteinander verbunden sind. Es wird angenommen, dass synaptische Plastizität aufgrund ihrer Eigenschaft, synaptische Gewichtungen innerhalb eines neuronalen Netzwerks zu verändern, eine Rolle bei der Informationsspeicherung spielt. Trotz jahrzehntelanger Forschung ist wenig über präsynaptische Plastizität bekannt, eine Form von Plastizität, die als aktivitätsabhängige Modulation der Neurotransmitterfreisetzung definiert wird. Bemerkenswerter Weise ist kein spezifischer Beitrag der präsynaptischen Plastizität zu Verhalten bekannt, hauptsächlich auf Grund eines Mangels an Methoden, die ihre spezifische Manipulation in vivo erlauben. Um diese Limitierungen zu überwinden, entwickelten und charakterisierten wir synaptoPAC, ein neues optogenetisches Werkzeug, das eine lichtvermittelte Induktion präsynaptischer Plastizität ermöglicht. SynaptoPAC wurde als Fusion der photoaktivierten Adenylylzyklase bPAC mit dem präsynaptischen Vesikelprotein Synaptophysin konzipiert. Dieses Design ermöglicht eine Erhöhung von cyclischem Adenosinmonophosphat (cAMP) in präsynaptischen Terminalen mittels Licht. Es wurde bereits gezeigt, dass erhöhtes präsynaptisches cAMP an bestimmten Synapsen eine Zunahme der Freisetzungswahrscheinlichkeit bewirkt und eine präsynaptische Potenzierung induziert. Mittels immunfluoreszenzmikroskopischer Bildgebung von kultivierten Neuronen zeigten wir eine Anreicherung von synaptoPAC in präsynaptischen Terminalen, was durch eine Ko- Lokalisation mit dem synaptischen Vesikelprotein VGLUT1 indiziert wurde. Wir verifizierten die lichtgesteuerte Erhöhung von cAMP durch synaptoPAC mittels elektrophysiologischer Ganzzellableitungen an ND7/23 Zellen, welche synatoPAC und den cAMP-gesteuerten SthK Kanal koexprimierten. Bei Ganzzellableitungen von synaptoPAC exprimierenden, autaptischen Kulturen hippokampaler Neurone beobachteten wir eine Zunahme der Transmitterfreisetzung während einer Stimulation mit Licht spezifisch in Körnerzellen, aber nicht in anderen Zelltypen, und eine damit einhergehende Veränderungen der Kurzzeitplastizität. In vivo Expression von synaptoPAC im Gyrus Dentatus und anschließende Feldpotenzialmessungen von exzitatorischen postsynaptischen Potenzialen in akuten Hirnschnitten ermöglichte uns, eine optisch induzierte Langzeitpotenizierung an Moosfaser-CA3 Synapsen zu demonstrieren. Interessanterweise bewirkte die Aktivierung dieses Werkzeugs keine Verstärkung der Transmitterfreisetzung in Schaffer Kollateral-CA1 Synapsen in in-vitro Messungen, was darauf hindeutet, dass synaptoPAC nur in Synapsen, die bereits für präsynaptische Plastizität prädisponiert sind, eine Potenzierung induzieren kann. Weitere Untersuchungen an hippocampalen Schnittpräparationen zur Veränderung der Kurzzeitplastizität durch synaptoPAC in Moosfasern bestätigten den präsynaptischen Charakter der optischen Potenzierung. Unsere Ergebnisse etablieren synaptoPAC als valides Werkzeug, das zur Beantwortung offener Forschungsfragen zur Rolle der präsynaptischen Plastizität im Gehirn eingesetzt werden kann, und unser Verständnis von Krankheiten verbessern könnte, welche durch eine Beeinträchtigungen dieser Art von neuronaler Plastizität gekennzeichnet sind

The interplay among psychopathology, personal resources, context-related factors and real-life functioning in schizophrenia: stability in relationships after 4 years and differences in network structure between recovered and non-recovered patients

Improving real-life functioning is the main goal of the most advanced integrated treatment programs in people with schizophrenia. The Italian Network for Research on Psychoses previously explored, by using network analysis, the interplay among illness-related variables, personal resources, context-related factors and real-life functioning in a large sample of patients with schizophrenia. The same research network has now completed a 4-year follow-up of the original sample. In the present study, we used network analysis to test whether the pattern of relationships among all variables investigated at baseline was similar at follow-up. In addition, we compared the network structure of patients who were classified as recovered at follow-up versus those who did not recover. Six hundred eighteen subjects recruited at baseline could be assessed in the follow-up study. The network structure did not change significantly from baseline to follow-up, and the overall strength of the connections among variables increased slightly, but not significantly. Functional capacity and everyday life skills had a high betweenness and closeness in the network at follow-up, as they had at baseline, while psychopathological variables remained more peripheral. The network structure and connectivity of non-recovered patients were similar to those observed in the whole sample, but very different from those in recovered subjects, in which we found few connections only. These data strongly suggest that tightly coupled symptoms/dysfunctions tend to maintain each other's activation, contributing to poor outcome in schizophrenia. Early and integrated treatment plans, targeting variables with high centrality, might prevent the emergence of self-reinforcing networks of symptoms and dysfunctions in people with schizophrenia

The interplay among psychopathology, personal resources, context-related factors and real-life functioning in schizophrenia: stability in relationships after 4 years and differences in network structure between recovered and non-recovered patients

Improving real-life functioning is the main goal of the most advanced integrated treatment programs in people with schizophrenia. The Italian Network for Research on Psychoses previously explored, by using network analysis, the interplay among illness-related variables, personal resources, context-related factors and real-life functioning in a large sample of patients with schizophrenia. The same research network has now completed a 4-year follow-up of the original sample. In the present study, we used network analysis to test whether the pattern of relationships among all variables investigated at baseline was similar at follow-up. In addition, we compared the network structure of patients who were classified as recovered at follow-up versus those who did not recover. Six hundred eighteen subjects recruited at baseline could be assessed in the follow-up study. The network structure did not change significantly from baseline to follow-up, and the overall strength of the connections among variables increased slightly, but not significantly. Functional capacity and everyday life skills had a high betweenness and closeness in the network at follow-up, as they had at baseline, while psychopathological variables remained more peripheral. The network structure and connectivity of non-recovered patients were similar to those observed in the whole sample, but very different from those in recovered subjects, in which we found few connections only. These data strongly suggest that tightly coupled symptoms/dysfunctions tend to maintain each other's activation, contributing to poor outcome in schizophrenia. Early and integrated treatment plans, targeting variables with high centrality, might prevent the emergence of self-reinforcing networks of symptoms and dysfunctions in people with schizophrenia

The association between insight and depressive symptoms in schizophrenia: Undirected and Bayesian network analyses

Background. Greater levels of insight may be linked with depressive symptoms among patients with schizophrenia, however, it would be useful to characterize this association at symptom-level, in order to inform research on interventions. Methods. Data on depressive symptoms (Calgary Depression Scale for Schizophrenia) and insight (G12 item from the Positive and Negative Syndrome Scale) were obtained from 921 community-dwelling, clinically-stable individuals with a DSM-IV diagnosis of schizophrenia, recruited in a nationwide multicenter study. Network analysis was used to explore the most relevant connections between insight and depressive symptoms, including potential confounders in the model (neurocognitive and social-cognitive functioning, positive, negative and disorganization symptoms, extrapyramidal symptoms, hostility, internalized stigma, and perceived discrimination). Bayesian network analysis was used to estimate a directed acyclic graph (DAG) while investigating the most likely direction of the putative causal association between insight and depression. Results. After adjusting for confounders, better levels of insight were associated with greater self-depreciation, pathological guilt, morning depression and suicidal ideation. No difference in global network structure was detected for socioeconomic status, service engagement or illness severity. The DAG confirmed the presence of an association between greater insight and self-depreciation, suggesting the more probable causal direction was from insight to depressive symptoms. Conclusions. In schizophrenia, better levels of insight may cause self-depreciation and, possibly, other depressive symptoms. Person-centered and narrative psychotherapeutic approaches may be particularly fit to improve patient insight without dampening self-esteem

In vivo hippocampal subfield volumes in bipolar disorder—A mega-analysis from The Enhancing Neuro Imaging Genetics through Meta-Analysis Bipolar Disorder Working Group

The hippocampus consists of anatomically and functionally distinct subfields that may be differentially involved in the pathophysiology of bipolar disorder (BD). Here we, the Enhancing NeuroImaging Genetics through Meta‐Analysis Bipolar Disorder workinggroup, study hippocampal subfield volumetry in BD. T1‐weighted magnetic resonance imaging scans from 4,698 individuals (BD = 1,472, healthy controls [HC] = 3,226) from 23 sites worldwide were processed with FreeSurfer. We used linear mixed‐effects models and mega‐analysis to investigate differences in hippocampal subfield volumes between BD and HC, followed by analyses of clinical characteristics and medication use. BD showed significantly smaller volumes of the whole hippocampus (Cohen's d = −0.20), cornu ammonis (CA)1 (d = −0.18), CA2/3 (d = −0.11), CA4 (d = −0.19), molecular layer (d = −0.21), granule cell layer of dentate gyrus (d = −0.21), hippocampal tail (d = −0.10), subiculum (d = −0.15), presubiculum (d = −0.18), and hippocampal amygdala transition area (d = −0.17) compared to HC. Lithium users did not show volume differences compared to HC, while non‐users did. Antipsychotics or antiepileptic use was associated with smaller volumes. In this largest study of hippocampal subfields in BD to date, we show widespread reductions in nine of 12 subfields studied. The associations were modulated by medication use and specifically the lack of differences between lithium users and HC supports a possible protective role of lithium in BD

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

Cambio climático: Efectos sobre los sectores más vulnerables en los países subdesarrollados

El concepto de vulnerabilidad se convierte en un elemento clave al analizar los problemas que sufren las comunidades en riesgo ocasionados por desastres naturales y ambientales. La definición de la misma incluye tres nociones: el grado de exposición de un grupo a un riesgo ambiental particular, el grado de sensibilidad a ser afectado por ese riesgo y la capacidad de resistir o recuperarse del daño asociado a la catástrofe, la resiliencia. La interacción entre la presión del elemento externo y la capacidad interna de respuesta, de moderación de potenciales daños y de adaptación de la sociedad afectada determina su vulnerabilidad, haciendo esto posible que distintos grupos expuestos al mismo cambio ambiental no sean vulnerables de igual manera.Las circunstancias y riesgos pueden ser muy dispares considerando la capacidad de resiliencia divergente entre países. Factores como la infraestructura del lugar, la información proveída por mejores sistemas de alerta o la rehabilitación de servicios básicos luego de ocurrido el desastre natural, llevarán a un menor número de víctimas ante la ocurrencia de algún desastre natural. Sin embargo, agregando a la comparación entre países, la diferencia entre los diversos estratos sociales un determinado territorio también puede ser relativamente significativa. En general, el grupo que se encuentra bajo la línea de la pobreza es mucho más vulnerable ante un desastre natural que los sectores que poseen mayor cantidad de recursos para resguardarse del riesgo. El nivel socioeconómico de los países también genera diferencias similares entre los mismos ante cambios ambientales.Las desventajas sociales y demográficas del sector más vulnerable hacen que este grupo se encuentre desprotegido en mayor medida frente a la ocurrencia de algún tipo de catástrofe natural. En este contexto, las instituciones encargadas de la política ambiental se tornan fundamentales para mejorar el desempeño ambiental del país a partir del desarrollo de marcos de acción, de reglas a aplicar para hacer frente a los desafíos que se presenten. La mayoría de los estudios sostiene que instituciones débiles conllevan a resultados ineficientes que generan una retroalimentación entre la degradación ambiental, la pobreza y la vulnerabilidad. El riesgo que corren los sectores más expuestos a cambios ambientales aumenta y la capacidad de recuperarse de los mismos disminuye a lo largo del tiempo si el país no cuenta con un marco institucional sólido que respalde a todos los estratos de la sociedad ante cualquier suceso que pueda acontecer.La valuación real, no meramente económica de los daños a los ecosistemas es importante tanto para el análisis de las poblaciones vulnerables, como también para observar el efecto negativo de la acción humana en el medioambiente y la incidencia de las instituciones en ambas problemáticas especialmente en espacios urbanos. Con este fin, el Notre Dame Global Adaptation Index o ND-GAIn es un índice de utilización abierta que busca mostrar cuales países están más expuestos a los impactos negativos del cambio climático y la actual vulnerabilidad que presentan los países a las catástrofes que podrían preceder, como inundaciones, sequías, ciclones, etc. De manera similar, el Índice de Desempeño Medioambiental es un índice construido por las Universidades de Yale y Columbia, en colaboración con la fundación Samuel Family y el Foro mundial de Economía. El objetivo de la creación de este índice fue diseñar una herramienta para facilitar la medición de los esfuerzos de resguardo ambiental que realizan las naciones, dividiendo dichos esfuerzos en dos principales ramas: la vitalidad de los ecosistemas y la salud ambiental.Con la información proporcionada por indicadores componentes de los índices arriba mencionados acerca de la vulnerabilidad económica y social, calidad institucional, indicadores de recursos y salud ambiental de diferentes naciones, se propone indagar acerca de cómo las leyes e instituciones que determinan la política ambiental establecen diferentes niveles de daño al medioambiente, sumando el estudio del impacto en los sectores de menores recursos de las sociedades urbanas, los cuales se identifican como de mayor vulnerabilidad ante el cambio climático. La metodología del trabajo a realizar es relativamente simple: se estudiará la relación descripta a través de un análisis cuantitativo, observando los indicadores generales de calidad institucional y de vulnerabilidad ante el cambio climático y sus consecuencias, y luego se analizará su correlación con el desempeño ambiental de los países ordenados por el ranking proporcionados por el índice EPI. Varios autores han tratado el tema propuesto por el trabajo aquí presentado, es decir, la relación entre la calidad institucional y el medioambiente. La propuesta que se suma es explorar la relación establecida a través de los postulados de la economía ecológica, observando el impacto en los sectores sociales vulnerables de manera multidimensional, especialmente la variación en el bienestar de las personas que se ven afectadas por el cambio climático y los daños generados al medioambiente por parte de los seres humanos, profundizando el análisis meramente económico.Los resultados indican una correlación alta de países con un marco institucional fuerte y buen desempeño ambiental, como también aquellos que muestran altos índices de corrupción, cortoplacismo y otras problemáticas institucionales se aparejan con niveles de contaminación y deterioro ambiental más elevado. El análisis a partir de la teoría de la Economía Ecológica también muestra claros indicios de que aquellas naciones que se encuentran en un segmento bajo de salud ambiental, tienen sectores vulnerables afectados de manera directa por las problemáticas mencionadas.Fil: Reyes Pontet, Mauro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Económicas y Sociales del Sur. Universidad Nacional del Sur. Departamento de Economía. Instituto de Investigaciones Económicas y Sociales del Sur; ArgentinaFil: London, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Económicas y Sociales del Sur. Universidad Nacional del Sur. Departamento de Economía. Instituto de Investigaciones Económicas y Sociales del Sur; ArgentinaFil: Oldani, Florentina. Universidad Nacional del Sur. Departamento de Economía; ArgentinaIX Jornadas de Economía EcológicaBarilocheArgentinaAsociación Argentino Uruguaya de Economía EcológicaUniversidad Nacional de Río NegroRed Iberoamericana de Economía Ecológic

Publisher Correction: Propagation of hippocampal ripples to the neocortex by way of a subiculum-retrosplenial pathway

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Antitumor Activity of Axitinib in Lung Carcinoids: A Preclinical Study

Lung carcinoids (LCs) comprise well-differentiated neuroendocrine tumors classified as typical (TCs) and atypical (ACs) carcinoids. Unfortunately, curative therapies remain elusive for metastatic LCs, which account for 25–30% of cases. This study evaluated the antitumor activity of axitinib (AXI), a second-generation tyrosine kinase inhibitor selectively targeting vascular endothelial growth factor receptors (VEGFR-1, VEGFR-2, VEGFR-3) in human lung TC (NCI-H727, UMC-11, NCI-H835) and AC (NCI-H720) cell lines. In vitro and in vivo (zebrafish) assays were performed following AXI treatment to gather several read-outs about cell viability, cell cycle, the secretion of proangiogenic factors, apoptosis, tumor-induced angiogenesis and migration. AXI demonstrated relevant antitumor activity in human LC cells, with pronounced effects observed in UMC-11 and NCI-H720, characterized by cell cycle perturbation and apoptosis induction. AXI significantly hindered tumor induced-angiogenesis in Tg(fli1a:EGFP)y1 zebrafish embryos implanted with all LC cell lines and also reduced the invasiveness of NCI-H720 cells, as well as the secretion of several proangiogenic factors. In conclusion, our study provides initial evidence supporting the potential anti-tumor activity of AXI in LC, offering a promising basis for future investigations in mammalian animal models and, eventually, progressing to clinical trials

SALM1 controls synapse development by promoting F-actin/PIP2-dependent Neurexin clustering

Synapse development requires spatiotemporally regulated recruitment of synaptic proteins. In this study, we describe a novel presynaptic mechanism of cis-regulated oligomerization of adhesion molecules that controls synaptogenesis. We identified synaptic adhesion-like molecule 1 (SALM1) as a constituent of the proposed presynaptic Munc18/CASK/Mint1/Lin7b organizer complex. SALM1 preferentially localized to presynaptic compartments of excitatory hippocampal neurons. SALM1 depletion in excitatory hippocampal primary neurons impaired Neurexin1β- and Neuroligin1-mediated excitatory synaptogenesis and reduced synaptic vesicle clustering, synaptic transmission, and synaptic vesicle release. SALM1 promoted Neurexin1β clustering in an F-actin- and PIP2-dependent manner. Two basic residues in SALM1's juxtamembrane polybasic domain are essential for this clustering. Together, these data show that SALM1 is a presynaptic organizer of synapse development by promoting F-actin/PIP2-dependent clustering of Neurexin