Efectos pleiotrópicos del agonista nicotínico a7, el PNU282987, y su posible aplicación en el tratamiento de enfermedades neurodegenerativas

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Farmacología y Terapéutica. Fecha de lectura: 18-11-2016El envejecimiento y las enfermedades neurodegenerativas se caracterizan por una disfunción en la señalización colinérgica, pérdida de conectividad sináptica, inflamación sub-crónica y alteraciones en la función y masa mitocondrial, lo que conduce a una menor producción energética y un aumento en el estrés oxidativo, entre otros. El receptor nicotínico alfa 7 (α7 nAChR) se ha postulado en los últimos años como una diana para el tratamiento de estas patologías. En este contexto, nos planteamos ahondar en los efectos celulares derivados de la activación del α7 nAChR (empleando el agonista PNU282987), y sus consecuencias sobre el control de la neuro-inflamación y la neuroprotección. En esta Tesis demostramos, empleando cultivos organotípicos de hipocampo de rata, cómo una inflamación y un daño mitocondrial sub-crónicos son suficientes para desencadenar de manera sinérgica las alteraciones patológicas asociadas a las enfermedades neurodegenerativas como son el estrés oxidativo, la proteinopatía y la neurodegeneración; siendo todas estas alteraciones prevenidas a través de la activación del α7 nAChR. Centrándonos en las células gliales, observamos que la activación del α7 nAChR conduce a un incremento en la masa mitocondrial y la capacidad energética celular a través de la activación de la vía Nrf2/HO-1/PGC-1α. Además, empleando un modelo in vivo de neuro-inflamación, demostramos que la activación de los α7 nAChRs centrales revierte el daño inflamatorio; perdiéndose estos efectos en animales envejecidos. Finalmente, evidenciamos que el incremento en masa mitocondrial observado en células gliales tras la activación del α7 nAChR también acontece en cultivos neuronales donde, además, la activación α7 nAChR conduce a un incremento en la densidad y el tamaño de las espinas dendríticas. Los resultados presentados en esta Tesis Doctoral nos han permitido ahondar en el conocimiento de la señalización colinérgica, demostrando por primera vez que la vía de señalización α7nAChR/Nrf2/HO-1/PGC-1α conduce a un incremento en la masa mitocondrial tanto en glía como en neuronas, lo cual podría explicar los efectos anti-inflamatorios, sinaptogénicos y neuroprotectores asociados a la activación del α7 nAChR.Ageing and neurodegeneration are characterized by a dysfunction in cholinergic signaling, loss in synaptic connectivity, sub-chronic inflammation and mitochondrial alterations such as decreased energetic production and higher oxidative stress, among others. The alpha 7 nicotinic receptor (α7 nAChR) is gaining interest as a pharmacological target for the treatment of these diseases. In this context, our objective is to deepen in the cellular effects taking place after the activation of α7 nAChR (using the agonist PNU282987), and to study its consequences in controlling neuroinflammation and neuroprotection. First of all, using organotypic hippocampal cultures, we demonstrate that sub-chronic low-grade inflammation and mitochondrial dysfunction can trigger synergistically the pathological alterations associated to neurodegenerative diseases: oxidative stress, proteinopathy and neurodegeneration. All these pathological alterations can be prevented by the activation of α7 nAChR. Focusing on glial cells, we describe that the activation of α7 nAChR triggers an increase in mitochondrial mass and cellular bioenergetic capacity via the axis Nrf2/HO-1/PGC-1α. Moreover, using an in vivo model of neuroinflammation, we demonstrate how the central activation of α7 nAChRs can reverse the inflammatory damage; being this anti-inflammatory effect lost in aged animals. Finally, we show that the increase in mitochondrial mass and respiration elicited by α7 nAChRs also occurs in neuronal cultures, where α7 nAChR activation produces an increase in the dendritic spine density and in the head size of the dendritic spines. The results presented in this Thesis have deepen in the knowledge of the cholinergic signaling, demonstrating for the first time that the signaling pathway α7nAChR/Nrf2/HO-1/PGC-1α leads to an increase in the mitochondrial mass, both in glial and neuronal cells, which could explain the anti-inflammatory, synaptogenic and neuroprotective effects associated to α7 nACh

Cine en compañía para prevenir enfermedades

El proyecto “Cine en compañía para prevenir enfermedades” es continuación del proyecto iniciado en 2017 (INNOVA-Docencia 18/2018, ApS-UCM 18/2019) y se encuadra en el campo de Salud Pública, higiene y prevención de enfermedad, dirigido a personas desfavorecidas o en riesgo de exclusión social. En esta edición se ha ampliado el área de conocimiento y profesores participantes, incluyendo no solo enfermedades infecciosas, como en ediciones anteriores, sino otras del ámbito de la Bioquímica y Biología Molecular. El proyecto es multidisciplinar e interfacultativo (21 tutores: profesores, colaboradores postdoctorales, doctorandos, estudiantes participantes en ediciones anteriores y técnico de laboratorio, de las Facultades de Farmacia, Biología y Medicina y del Hospital 12 de Octubre) y en él han participado 41 estudiantes de distintos Grados (Biología, Bioquímica, Ciencia y Tecnología de los Alimentos, Derecho, Farmacia, Ingeniería Electrónica) y Postgrados (Máster en Biología Sanitaria, y en Microbiología y Parasitología: Investigación y Desarrollo; Doctorado en Bioquímica y Biología Molecular) y participantes en la asignatura Transversal “Ciencia para la Sociedad”. La necesidad social detectada y atendida es la situación de algunos colectivos, por ejemplo, personas sin hogar, mujeres en exclusión, adictos a drogas, presidiarios o familias residentes en áreas no salubres, de una mayor exposición a determinadas enfermedades debido a sus condiciones de vida (enfermedades infecciosas, mentales, metabólicas derivadas de adicciones o alcoholismo), además de que encuentran escasas posibilidades de conocer cómo prevenirlas y la forma adecuada de recibir tratamiento. Adicionalmente, y no menos importante, acusan una carencia severa de compañía, atención y escucha de sus necesidades. Los estudiantes de universidad que cursan estudios en el campo de Ciencias y Ciencias de la Salud estudian estas enfermedades, por lo que pueden ayudar a estos colectivos en la mejora de prácticas higiénico-sanitarias, así como al acceso a la información para su prevención y tratamiento. Las actividades desarrolladas en el proyecto han consistido en el acompañamiento y desarrollo de una actividad lúdica mediante la proyección de películas comerciales que traten una enfermedad de interés en el colectivo a atender, seguida de coloquio para ayudar a conocer las formas adecuadas de prevención y tratamiento. Los equipos de 4-5 estudiantes (de distintas titulaciones y cursos) y dos tutores (senior y junior) han realizado varias visitas a centros sociales atendidos por Fundaciones con las que existe convenio de la UCM (centros de día para personas sin hogar, mujeres en exclusión, discapacitados o presidiarios, gestionados por Cáritas, Hogar-Sí, Diaconía, Medinacelli). Han investigado en profundidad las enfermedades que afectan y de interés del grupo atendido, seleccionado y analizado críticamente películas adecuadas, preparado materiales divulgativos (carteles, juegos) y diseñado y analizado encuestas para evaluar su actividad por parte de las personas atendidas y los coordinadores de los centros. Los resultados de las encuestas a todos los participantes (tutores, estudiantes, centros) y la recogida de opiniones y memorias de los estudiantes muestran una alta consecución de los objetivos de aprendizaje previstos, refuerzo de contenidos específicos de los estudios y, sobre todo, trabajo y adquisición de competencias transversales como trabajo en equipo, coordinación y asunción de responsabilidades, análisis crítico o expresión científica divulgativa. En cuanto a los objetivos de servicio, destaca la utilidad del proyecto en atención e información a los colectivos, la aplicación de los estudios a situaciones reales en atención a personas desfavorecidas y el valor social del proyecto

Oral saliva swab reverse transcription PCR for Covid-19 in the paediatric population

8Pág. Centro de Investigación en Sanidad Animal (CISA)To evaluate the performance of oral saliva swab (OSS) reverse transcription PCR (RT-PCR) compared with RT-PCR and antigen rapid diagnostic test (Ag-RDT) on nasopharyngeal swabs (NPS) for SARS-CoV-2 in children.The study was funded by: Project PI20/00095, from the Instituto de Salud Carlos III (Ministry of Economy, Industry and Competitiveness) and cofounded by the European Regional Development Fund, by Infanta Sofia University Hospital and Henares University Hospital Foundation for Biomedical Research and Innovation (FIIB HUIS HHEN), and by SERMAS-Fundación para la Investigación Biomédica del Hospital 12 de Octubre. EC-C is supported by the Spanish Society of Paediatrics (Asociación Española de Pediatría); Grant COVID-19 EPICO-AEP 2020. JMM is funded by SERMAS-Fundación para la Investigación Biomédica del Hospital Infanta Sofía y del Henares and by Universidad Europea de Madrid, Spain. MdlS is funded by Grant Cantera de Investigación Santander, Fundación Universidad Europea de Madrid, Spain. ED is funded by the Juan de la Cierva–Incorporación granted by the Spanish Ministry of Science and Innovation. DB-G is funded by the Spanish Ministry of Science and Innovation—Instituto de Salud Carlos III and Fondos FEDER by ’Contratos para la intensificación de la actividad investigadora en el Sistema Nacional de Salud, 2020 (INT20/00086)’.Peer reviewe

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Heme-Oxygenase I and PCG-1α Regulate Mitochondrial Biogenesis via Microglial Activation of Alpha7 Nicotinic Acetylcholine Receptors Using PNU282987

Aims: A loss in brain acetylcholine and cholinergic markers, subchronic inflammation, and impaired mitochondrial function, which lead to low-energy production and high oxidative stress, are common pathological factors in several neurodegenerative diseases (NDDs). Glial cells are important for brain homeostasis, and microglia controls the central immune response, where α7 acetylcholine nicotinic receptors (nAChR) seem to play a pivotal role; however, little is known about the effects of this receptor in metabolism. Therefore, the aim of this study was to evaluate if glial mitochondrial energetics could be regulated through α7 nAChR. Results: Primary glial cultures treated with the α7 nicotinic agonist PNU282987 increased their mitochondrial mass and their mitochondrial oxygen consumption without increasing oxidative stress; these changes were abolished when nuclear erythroid 2-related factor 2 (Nrf2) was absent, heme oxygenase-1 (HO-1) was inhibited, or peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) was silenced. More specifically, microglia of animals treated intraperitoneally with the α7 nAChR agonist PNU282987 (10 mg/kg) showed a significant increase in mitochondrial mass. Interestingly, LysMcre-Hmox1Δ/Δ and PGC-1α-/- animals showed lower microglial mitochondrial levels and treatment with PNU282987 did not produce effects on mitochondrial levels. Innovation: Increases in microglial mitochondrial mass and metabolism can be achieved via α7 nAChR by a mechanism that implicates Nrf2, HO-1, and PGC-1α. This signaling pathway could open a new strategy for the treatment of NDDs, such as Alzheimer's, characterized by a reduction of cholinergic markers. Conclusion: α7 nAChR signaling increases glial mitochondrial mass, both in vitro and in vivo, via HO-1 and PCG-1α. These effects could be of potential benefit in the context of NDDs. Antioxid. Redox Signal. 27, 93-105.Depto. de Bioquímica y Biología MolecularFac. de MedicinaTRUEpu

Agmatine, by Improving Neuroplasticity Markers and Inducing Nrf2, Prevents Corticosterone-Induced Depressive-Like Behavior in Mice

Agmatine, an endogenous neuromodulator, is a potential candidate to constitute an adjuvant/monotherapy for the management of depression. A recent study by our group demonstrated that agmatine induces Nrf2 and protects against corticosterone effects in a hippocampal neuronal cell line. The present study is an extension of this previous study by assessing the antidepressant-like effect of agmatine in an animal model of depression induced by corticosterone in mice. Swiss mice were treated simultaneously with agmatine or imipramine at a dose of 0.1 mg/kg/day (p.o.) and corticosterone for 21 days and the daily administrations of experimental drugs were given immediately prior to corticosterone (20 mg/kg/day, p.o.) administrations. Wild-type C57BL/6 mice (Nrf2 (+/+)) and Nrf2 KO (Nrf2 (-/-)) were treated during 21 days with agmatine (0.1 mg/kg/day, p.o.) or vehicle. Twenty-four hours after the last treatments, the behavioral tests and biochemical assays were performed. Agmatine treatment for 21 days was able to abolish the corticosterone-induced depressive-like behavior and the alterations in the immunocontent of mature BDNF and synaptotagmin I, and in the serotonin and glutamate levels. Agmatine also abolished the corticosterone-induced changes in the morphology of astrocytes and microglia in CA1 region of hippocampus. In addition, agmatine treatment in control mice increased noradrenaline, serotonin, and dopamine levels, CREB phosphorylation, mature BDNF and synaptotagmin I immunocontents, and reduced pro-BDNF immunocontent in the hippocampus. Agmatine's ability to produce an antidepressant-like effect was abolished in Nrf2 (-/-) mice. The present results reinforce the participation of Nrf2 in the antidepressant-like effect produced by agmatine and expand literature data concerning its mechanisms of action.Depto. de Bioquímica y Biología MolecularFac. de MedicinaTRUEpu

Sequential activation of microglia and astrocyte cytokine expression precedes increased iba-1 or GFAP immunoreactivity following systemic immune challenge

Activation of the peripheral immune system elicits a coordinated response from the central nervous system. Key to this immune to brain communication is that glia, microglia, and astrocytes, interpret and propagate inflammatory signals in the brain that influence physiological and behavioral responses. One issue in glial biology is that morphological analysis alone is used to report on glial activation state. Therefore, our objective was to compare behavioral responses after in vivo immune (lipopolysaccharide, LPS) challenge to glial specific mRNA and morphological profiles. Here, LPS challenge induced an immediate but transient sickness response with decreased locomotion and social interaction. Corresponding with active sickness behavior (2-12 h), inflammatory cytokine mRNA expression was elevated in enriched microglia and astrocytes. Although proinflammatory cytokine expression in microglia peaked 2-4 h after LPS, astrocyte cytokine, and chemokine induction was delayed and peaked at 12 h. Morphological alterations in microglia (Iba-1(+)) and astrocytes (GFAP(+)), however, were undetected during this 2-12 h timeframe. Increased Iba-1 immunoreactivity and de-ramified microglia were evident 24 and 48 h after LPS but corresponded to the resolution phase of activation. Morphological alterations in astrocytes were undetected after LPS. Additionally, glial cytokine expression did not correlate with morphology after four repeated LPS injections. In fact, repeated LPS challenge was associated with immune and behavioral tolerance and a less inflammatory microglial profile compared with acute LPS challenge. Overall, induction of glial cytokine expression was sequential, aligned with active sickness behavior, and preceded increased Iba-1 or GFAP immunoreactivity after LPS challengeDepto. de Bioquímica y Biología MolecularFac. de MedicinaTRUEpu

Alpha7 nicotinic receptor activation protects against oxidative stress via heme-oxygenase I induction

Subchronic oxidative stress and inflammation are being increasingly implicated in the pathogenesis of numerous diseases, such as Alzheimer's or Parkinson's disease. This study was designed to evaluate the potential protective role of α7 nicotinic receptor activation in an in vitro model of neurodegeneration based on subchronic oxidative stress. Rat organotypic hippocampal cultures (OHCs) were exposed for 4 days to low concentration of lipopolysaccharide (LPS) and the complex III mitochondrial blocker, antimycin-A. Antimycin-A (0.1μM) and lipopolysaccharide (1ng/ml) caused low neurotoxicity on their own, measured as propidium iodide fluorescence in CA1 and CA3 regions. However, their combination (LPS/AA) caused a greater detrimental effect, in addition to mitochondrial depolarization, overproduction of reactive oxygen species (ROS) and Nox4 overexpression. Antimycin-A per se increased ROS and mitochondrial depolarization, although these effects were significantly higher when combined with LPS. More interesting was the finding that exposure of OHCs to the combination of LPS/AA triggered aberrant protein aggregation, measured as thioflavin S immunofluorescence. The α7 nicotinic receptor agonist, PNU282987, prevented the neurotoxicity and the pathological hallmarks observed in the LPS/AA subchronic toxicity model (oxidative stress and protein aggregates); these effects were blocked by α-bungarotoxin and tin protoporphyrin, indicating the participation of α7 nAChRs and heme-oxygenase I induction. In conclusion, subchronic exposure of OHCs to low concentration of antimycin-A plus LPS reproduced pathological features of neurodegenerative disorders. α7 nAChR activation ameliorated these alterations by a mechanism involving heme-oxygenase I induction.Depto. de Bioquímica y Biología MolecularFac. de MedicinaTRUEpu

Subthreshold Concentrations of Melatonin and Galantamine Improves Pathological AD-Hallmarks in Hippocampal Organotypic Cultures

Melatonin is a neurohormone whose levels are significantly reduced or absent in Alzheimer's disease (AD) patients. In these patients, acetylcholinesterase inhibitors (AChEI) are the major drug class used for their treatment; however, they present unwanted cholinergic side effects and have provided limited efficacy in clinic. Because combination therapy is being extensively used to treat different pathological diseases such as cancer or acquired immune deficiency syndrome, we posed this study to evaluate if melatonin in combination with an AChEI, galantamine, could provide beneficial properties in a novel in vitro model of AD. Thus, we subjected organotypic hippocampal cultures (OHCs) to subtoxic concentrations of β-amyloid (0.5 μM βA) plus okadaic acid (1 nM OA), for 4 days. This treatment increased by 95 % cell death, which was mainly apoptotic as shown by positive TUNEL staining. In addition, the combination of βA/OA increased Thioflavin S aggregates, hyperphosphorylation of Tau, oxidative stress (increased DCFDA fluorescence), and neuroinflammation (increased IL-1β and TNFα). Under these experimental conditions, melatonin (1-1000 nM) and galantamine (10-1000 nM), co-incubated with the toxic stimuli, caused a concentration-dependent neuroprotection; maximal neuroprotective effect was achieved at 1 μM of melatonin and galantamine. Most effective was the finding that combination of sub-effective concentrations of melatonin (1 nM) and galantamine (10 nM) provided a synergic anti-apoptotic effect and reduction of most of the AD-related pathological hallmarks observed in the βA/OA model. Therefore, we suggest that supplementation of melatonin in combination with lower doses of AChEIs could be an interesting strategy for AD patients.Depto. de Bioquímica y Biología MolecularFac. de MedicinaTRUEpu

New melatonin–cinnamate hybrids as multi-target drugs for neurodegenerative diseases: Nrf2-induction, antioxidant effect and neuroprotection

Neurodegenerative diseases share many pathological pathways, such as abnormal protein aggregation, mitochondrial dysfunction, extensive oxidative stress and neuroinflammation. Cells have an intrinsic mechanism of protection, the Nrf2 transcriptional factor, known as the master regulator of redox homeostasis. Results: Based on the common features of these diseases we have designed a multi-target hybrid structure derived from melatonin and ethyl cinnamate. The obtained derivatives were Nrf2 inducers and potent-free radical scavengers. These new compounds showed a very interesting neuroprotective profile in several in vitro models of oxidative stress, Alzheimer's disease and brain ischemia. Conclusion: We have designed a new hybrid structure with complementary activities. We have identified compound 5h as an interesting Nrf2 inducer, very potent antioxidant and neuroprotectant.European CommissionMinisterio de Sanidad(España)Ministerio de Economía, Comercio y Empresa(España)Instituto de Salud Carlos IIIMinisterio de Educación, Cultura y Deporte(España)Depto. de Química en Ciencias FarmacéuticasFac. de FarmaciaTRUEpu