Estrategias antiinflamatorias para la protección de la unidad neurovascular en modelos de isquemia cerebral

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Farmacología. Fecha de lectura: 20-12-2021El ictus isquémico es la segunda causa de muerte a nivel mundial y la primera en discapacidad a largo plazo. Supone entre el 80 y el 85% de los accidentes cerebrovasculares y se debe a la reducción del flujo sanguíneo en un área determinada del cerebro. La disminución del flujo sanguíneo cerebral desencadena una fuerte respuesta inflamatoria y la muerte celular. Una respuesta inflamatoria descontrolada puede producir daños irreversibles y un peor pronóstico en los pacientes que han sufrido un ictus isquémico. En la fase aguda del ictus sólo existen dos tratamientos que facilitan la recanalización del vaso obstruido, la trombólisis venosa con el rtPA y la trombectomía mecánica. Ambos tratamientos tienen una estrecha ventana terapéutica, y numerosos efectos secundarios. El estudio de los procesos fisiopatológicos que ocurren tras la isquemia cerebral es fundamental para desarrollar nuevas estrategias farmacológicas con el objetivo de proteger la unidad neurovascular. Por ello, debido a la necesidad clínica existente, en esta Tesis Doctoral hemos validado dos posibles dianas terapéuticas, el receptor TLR4 y el inflamasoma NLRP3, cuya inhibición farmacológica tiene efectos neuroprotectores. El compuesto E5564 es un inhibidor selectivo del receptor TLR4, y tiene efectos neuroprotectores en diferentes modelos in vitro de isquemia cerebral. En un modelo in vivo de isquemia cerebral, donde tiene lugar la oclusión transitoria de la arteria cerebral media (tMCAO) seguida de una reperfusión, el E5564 reduce la expresión de diferentes citoquinas y quimioquinas proinflamatorias, el volumen de infarto, la pérdida de funcionalidad de la barrera hematoencefálica (BHE), y mejora la función neuromotora. El compuesto MCC950, un inhibidor selectivo del inflamasoma NLRP3, también presenta un efecto neuroprotector en un modelo animal de tMCAO seguido de una reperfusión. La inhibición farmacológica del inflamasoma NLRP3 reduce el volumen de infarto, la pérdida de funcionalidad de la BHE, los niveles de CCL2 circulantes y la infiltración de células inmunes periféricas en el parénquima cerebral después de una isquemia cerebral. Sin embargo, la inhibición farmacológica del inflamasoma NLRP3 con MCC950 no redujo el volumen de infarto en dos modelos animales de oclusión permanente de la arteria cerebral media. Por otro lado, MCC950 a las 24 horas después del modelo tMCAO reducía los niveles séricos de las proteínas que formas las uniones estrechas características de la BHE. Por último, la cobertura de pericitos que envuelve a los vasos sanguíneos cerebrales disminuye a las 4 y 24 horas después de un modelo tMCAO, pudiendo estar relacionado con la pérdida de funcionalidad de la BHE. Teniendo en cuenta los resultados obtenidos a lo largo de la Tesis Doctoral, proponemos, por un lado, el receptor TLR4, y, por otro lado, el inflamasoma NLRP3, como posibles dianas terapéuticas para frenar la respuesta inflamatoria en la fase aguda del ictus isquémicoLa investigación presente ha sido financiada por proyectos del Fondo de Investigaciones Sanitarias (FIS) (ISCIII/FEDER) FI17/00010, PI16/00735 y PI19/00082 concedidos al director de la Tesis Doctoral, el Dr. Javier Ege

Multiple Morphometric Assessment of Microglial Cells in Deafferented Spinal Trigeminal Nucleus.

Microglia (MG) are the first cells to react to the abnormal incoming signals that follow an injury of sensory nerves and play a critical role in the development and maintenance of neuropathic pain, a common sequel of nerve injuries. Here we present population data on cell number, soma size, and length of processes of MG in the caudal division of the spinal trigeminal nucleus (Sp5C) in control mice and at the peak of microgliosis (7 days) following unilateral transection of the infraorbital nerve (IoN). The study is performed combining several bias- and assumption-free imaging and stereological approaches with different immunolabeling procedures, with the objective of tackling some hard problems that often hinder proper execution of MG morphometric studies. Our approach may easily be applied to low-density MG populations, but also works, with limited biases, in territories where MG cell bodies and processes form dense meshworks. In controls, and contralaterally to the deafferented side, MG cell body size and shape and branching pattern matched well the descriptions of “resting” or “surveillant” MG described elsewhere, with only moderate intersubject variability. On the superficial laminae of the deafferented side, however, MG displayed on average larger somata and remarkable diversity in shape. The number of cells and the length of MG processes per mm3 increased 5 and 2.5 times, respectively, indicating a net 50% decrease in the mean length of processes per cell. By using specific immunolabeling and cell sorting of vascular macrophages, we found only a negligible fraction of these cells in Sp5C, with no differences between controls and deafferented animals, suggesting that blood-borne monocytes play at most a very limited role in the microgliosis occurring following sensory nerve deafferentation. In sum, here we present reliable morphometric data on MG in control and deafferented trigeminal nuclei using efficient methods that we propose may equally be applied to any morphometric population analysis of these cells under different physiological or pathological conditions.post-print1841 K

TLR4-pathway impairs synaptic number and cerebrovascular functions through astrocyte activation following traumatic brain injury

Background and purpose: Activation of astrocytes contributes to synaptic remodelling, tissue repair and neuronal survival following traumatic brain injury (TBI). The mechanisms by which these cells interact to resident/infiltrated inflammatory cells to rewire neuronal networks and repair brain functions remain poorly understood. Here, we explored how TLR4-induced astrocyte activation modified synapses and cerebrovascular integrity following TBI. Experimental approach: To determine how functional astrocyte alterations induced by activation of TLR4 pathway in inflammatory cells regulate synapses and neurovascular integrity after TBI, we used pharmacology, genetic approaches, live calcium imaging, immunofluorescence, flow cytometry, blood-brain barrier (BBB) integrity assessment and molecular and behavioural methods. Key results: Shortly after a TBI, there is a recruitment of excitable and reactive astrocytes mediated by TLR4 pathway activation with detrimental effects on post-synaptic density-95 (PSD-95)/vesicular glutamate transporter 1 (VGLUT1) synaptic puncta, BBB integrity and neurological outcome. Pharmacological blockage of the TLR4 pathway with resatorvid (TAK-242) partially reversed many of the observed effects. Synapses and BBB recovery after resatorvid administration were not observed in IP3 R2-/- mice, indicating that effects of TLR4 inhibition depend on the subsequent astrocyte activation. In addition, TBI increased the astrocytic-protein thrombospondin-1 necessary to induce a synaptic recovery in a sub-acute phase. Conclusions and implications: Our data demonstrate that TLR4-mediated signalling, most probably through microglia and/or infiltrated monocyte-astrocyte communication, plays a crucial role in the TBI pathophysiology and that its inhibition prevents synaptic loss and BBB damage accelerating tissue recovery/repair, which might represent a therapeutic potential in CNS injuries and disorders.This work was supported by grants from the Instituto de Salud Carlos III (ISCIII) (Programa Miguel Servet II Grants CPII19/00005;PI16/00735; PI19/00082 to JE; and PI18/00357 to DC, partiallyfunded by FEDER - European Union ‘Una manera de hacer Europa’) and Fundación Mutua Madrileña to JE; European Union's Horizon2020 research and innovation programme under the H2020 MarieSkłodowska-Curie Actions grant agreement no. 794926 and StopFuga de Cerebros Roche Pharma to JMR; and Ministerio de Ciencia e Innovación RTI2018-094887-B-I00 and RYC-2016-20414 to MN andRYC2019-026870-I to JMR. DC, MCO, VVS and EFL are hired bySESCAM

TLR4-pathway impairs synaptic number and cerebrovascular functions through astrocyte activation following traumatic brain injury.

Background and purpose: Activation of astrocytes contributes to synaptic remodelling, tissue repair and neuronal survival following traumatic brain injury (TBI). The mechanisms by which these cells interact to resident/infiltrated inflammatory cells to rewire neuronal networks and repair brain functions remain poorly understood. Here, we explored how TLR4-induced astrocyte activation modified synapses and cerebrovascular integrity following TBI. Experimental approach: To determine how functional astrocyte alterations induced by activation of TLR4 pathway in inflammatory cells regulate synapses and neurovascular integrity after TBI, we used pharmacology, genetic approaches, live calcium imaging, immunofluorescence, flow cytometry, blood-brain barrier (BBB) integrity assessment and molecular and behavioural methods. Key results: Shortly after a TBI, there is a recruitment of excitable and reactive astrocytes mediated by TLR4 pathway activation with detrimental effects on post-synaptic density-95 (PSD-95)/vesicular glutamate transporter 1 (VGLUT1) synaptic puncta, BBB integrity and neurological outcome. Pharmacological blockage of the TLR4 pathway with resatorvid (TAK-242) partially reversed many of the observed effects. Synapses and BBB recovery after resatorvid administration were not observed in IP3 R2-/- mice, indicating that effects of TLR4 inhibition depend on the subsequent astrocyte activation. In addition, TBI increased the astrocytic-protein thrombospondin-1 necessary to induce a synaptic recovery in a sub-acute phase. Conclusions and implications: Our data demonstrate that TLR4-mediated signalling, most probably through microglia and/or infiltrated monocyte-astrocyte communication, plays a crucial role in the TBI pathophysiology and that its inhibition prevents synaptic loss and BBB damage accelerating tissue recovery/repair, which might represent a therapeutic potential in CNS injuries and disorders.This work was supported by grants from the Instituto de Salud Carlos III (ISCIII) (Programa Miguel Servet II Grants CPII19/00005;PI16/00735; PI19/00082 to JE; and PI18/00357 to DC, partiallyfunded by FEDER - European Union ‘Una manera de hacer Europa’) and Fundación Mutua Madrileña to JE; European Union's Horizon2020 research and innovation programme under the H2020 MarieSkłodowska-Curie Actions grant agreement no. 794926 and StopFuga de Cerebros Roche Pharma to JMR; and Ministerio de Ciencia e Innovación RTI2018-094887-B-I00 and RYC-2016-20414 to MN andRYC2019-026870-I to JMR. DC, MCO, VVS and EFL are hired bySESCAM

Synthesis and Pharmacological Evaluation of New N-Sulfonylureas as NLRP3 Inflammasome Inhibitors: Identification of a Hit Compound to Treat Gout

NLRP3 is involved in the pathophysiology of several inflammatory diseases. Therefore, there is high current interest in the clinical development of new NLRP3 inflammasome small inhibitors to treat these diseases. Novel N-sulfonylureas were obtained by the replacement of the hexahydroindacene moiety of the previously described NLRP3 inhibitor MCC950. These new derivatives show moderate to high potency in inhibiting IL-1β release in vitro. The greatest effect was observed for compound 4b, which was similar to MCC950. Moreover, compound 4b was able to reduce caspase-1 activation, oligomerization of ASC, and therefore, IL-1β processing. Additional in silico predictions confirmed the safety profile of compound 4b, and in vitro studies in AML12 hepatic cells confirmed the absence of toxicological effects. Finally, we evaluated in vivo anti-inflammatory properties of compound 4b, which showed a significant anti-inflammatory effect and reduced mechanical hyperalgesia at 3 and 10 mg/kg (i.p.) in an in vivo mouse model of gout.J.E. thanks Fondo de Investigaciones Sanitarias (ISCIII/ FEDER) (Programa Miguel Servet: CP19/00005 and PI19/ 00082) and Fundación Mutua Madrileñ a. D.D.-I. thanks the Spanish Ministry of Science, Innovation, and Universities for predoctoral FPU grant

Protective role of nrf2 in renal disease

Chronic kidney disease (CKD) is one of the fastest-growing causes of death and is predicted to become by 2040 the fifth global cause of death. CKD is characterized by increased oxidative stress and chronic inflammation. However, therapies to slow or prevent CKD progression remain an unmet need. Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that plays a key role in protection against oxidative stress and regulation of the inflammatory response. Consequently, the use of compounds targeting Nrf2 has generated growing interest for nephrologists. Pre-clinical and clinical studies have demonstrated that Nrf2-inducing strategies prevent CKD progression and protect from acute kidney injury (AKI). In this article, we review current knowledge on the protective mechanisms mediated by Nrf2 against kidney injury, novel therapeutic strategies to induce Nrf2 activation, and the status of ongoing clinical trials targeting Nrf2 in renal diseasesThe authors’work has been supported by grants FIS/Fondos FEDER (PI17/00130, PI17/00257, PI17/01495, PI18/01386, PI19/00815, PI20/00375, PI20/00487 ISCIII-RETIC REDinREN RD016/0009), Sociedad Española de Nefrología, FRIAT, Comunidad de Madrid en Biomedicina B2017/BMD-3686 CIFRA2-CM. Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM) and Cardiovascular (CIBERCV), Spanish Ministry of Science and Innovation (RTI2018-098788-B-100, DTS17/00203, DTS19/00093, RYC-2017-22369, FJC2019-042028), The “PFIS” and “Sara Borrell” training program of the ISCIII supported the salary of MGH (FI18/00310), SR-M (CD19/00021), and CH-B (CP16/00017). Spanish Ministerio de Ciencia, Innovación y Universidades (MICIU) grant RTI2018-100695-B-I00, Junta de Andalucía grants P18-RT-4264, 1263735-R and BIO-276, the FEDER Funding Program from the European Union, and Universidad de Córdoba (to J.M.V.

Serum amyloid a1/toll-like receptor-4 Axis, an important link between inflammation and outcome of TBI patients

Traumatic brain injury (TBI) is one of the leading causes of mortality and disability world-wide without any validated biomarker or set of biomarkers to help the diagnosis and evaluation of the evolution/prognosis of TBI patients. To achieve this aim, a deeper knowledge of the biochemical and pathophysiological processes triggered after the trauma is essential. Here, we identified the serum amyloid A1 protein-Toll-like receptor 4 (SAA1-TLR4) axis as an important link between inflammation and the outcome of TBI patients. Using serum and mRNA from white blood cells (WBC) of TBI patients, we found a positive correlation between serum SAA1 levels and injury severity, as well as with the 6-month outcome of TBI patients. SAA1 levels also correlate with the presence of TLR4 mRNA in WBC. In vitro, we found that SAA1 contributes to inflammation via TLR4 activation that releases inflammatory cytokines, which in turn increases SAA1 levels, establishing a positive proinflammatory loop. In vivo, post-TBI treatment with the TLR4-antagonist TAK242 reduces SAA1 levels, improves neurobehavioral outcome, and prevents blood–brain barrier disruption. Our data support further evaluation of (i) post-TBI treatment in the presence of TLR4 inhibition for limiting TBI-induced damage and (ii) SAA1-TLR4 as a biomarker of injury progression in TBI patientsThis work was supported by grants from Fundación Mutua Madrileña and Fondo de Investigaciones Sanitarias (FIS) (ISCIII/FEDER) (Programa Miguel Servet CP14/00008; CPII19/00005; PI16/00735; PI19/00082) to JE, RYC2019-026870-I to JMR and PI18/01387 to A

Mitochondrial Na+ controls oxidative phosphorylation and hypoxic redox signalling

All metazoans depend on O2 delivery and consumption by the mitochondrial oxidative phosphorylation (OXPHOS) system to produce energy. A decrease in O2 availability (hypoxia) leads to profound metabolic rewiring. In addition, OXPHOS uses O2 to produce reactive oxygen species (ROS) that can drive cell adaptations through redox signalling, but also trigger cell damage1–4, and both phenomena occur in hypoxia4–8. However, the precise mechanism by which acute hypoxia triggers mitochondrial ROS production is still unknown. Ca2+ is one of the best known examples of an ion acting as a second messenger9, yet the role ascribed to Na+ is to serve as a mere mediator of membrane potential and collaborating in ion transport10. Here we show that Na+ acts as a second messenger regulating OXPHOS function and ROS production by modulating fluidity of the inner mitochondrial membrane (IMM). We found that a conformational shift in mitochondrial complex I during acute hypoxia11 drives the acidification of the matrix and solubilization of calcium phosphate precipitates. The concomitant increase in matrix free-Ca2+ activates the mitochondrial Na+/Ca2+ exchanger (NCLX), which imports Na+ into the matrix. Na+ interacts with phospholipids reducing IMM fluidity and mobility of free ubiquinone between complex II and complex III, but not inside supercomplexes. As a consequence, superoxide is produced at complex III, generating a redox signal. Inhibition of mitochondrial Na+ import through NCLX is sufficient to block this pathway, preventing adaptation to hypoxia. These results reveal that Na+ import into the mitochondrial matrix controls OXPHOS function and redox signalling through an unexpected interaction with phospholipids, with profound consequences in cellular metabolism

Quinolylnitrones derivatives for use in the prevention and treatment of cerebral ischemia, ischemic stroke and neurodegenerative diseases

[ES] Derivados de quinolilnitronas para su uso en la prevención y el tratamiento de la isquemia cerebral, ictus isquémico y enfermedades neurodegenerativas. Derivados de quinolilnitronas de fórmula I, donde el significado de los sustituyentes es el descrito en la descripción, útiles para el tratamiento y/o prevención de la isquemia cerebral, ictus isquémico y enfermedades neurodegenerativas.[EN] Quinolylnitrone derivatives for use in the prevention and treatment of cerebral ischemia, ischemic stroke and neurodegenerative diseases. Quinolylnitrone derivatives of formula I, where the meaning of the substituents is as described in the description, useful for the treatment and/or prevention of cerebral ischemia, ischemic stroke and neurodegenerative diseases.NoConsejo Superior de Investigaciones Científicas (CSIC), Fundación de Investigación Biomédica del Hospital Universitario La Princesa, Fundación para la Investigación Biomédica del Hospital Universitario Ramon y CajalA1 Solicitud de patente con informe sobre el estado de la técnic

Activation of NLRP3 Is Required for a Functional and Beneficial Microglia Response after Brain Trauma

Despite the numerous research studies on traumatic brain injury (TBI), many physiopathologic mechanisms remain unknown. TBI is a complex process, in which neuroinflammation and glial cells play an important role in exerting a functional immune and damage-repair response. The activation of the NLRP3 inflammasome is one of the first steps to initiate neuroinflammation and so its regulation is essential. Using a closed-head injury model and a pharmacological (MCC950; 3 mg/kg, pre- and post-injury) and genetical approach (NLRP3 knockout (KO) mice), we defined the transcriptional and behavioral profiles 24 h after TBI. Wild-type (WT) mice showed a strong pro-inflammatory response, with increased expression of inflammasome components, microglia and astrocytes markers, and cytokines. There was no difference in the IL1β production between WT and KO, nor compensatory mechanisms of other inflammasomes. However, some microglia and astrocyte markers were overexpressed in KO mice, resulting in an exacerbated cytokine expression. Pretreatment with MCC950 replicated the behavioral and blood–brain barrier results observed in KO mice and its administration 1 h after the lesion improved the damage. These findings highlight the importance of NLRP3 time-dependent activation and its role in the fine regulation of glial response