Mice Lacking Functional Fas Death Receptors Are Protected from Kainic Acid-Induced Apoptosis in the Hippocampus

© 2014, Springer Science+Business Media New York. The Fas receptor (FasR)/Fas ligand (FasL) system plays a significant role in the process of neuronal loss in neurological disorders. Thus, in the present study, we used a real-time PCR array focused apoptosis (Mouse Apoptosis RT2 PCR Array) to study the role of the Fas pathway in the apoptotic process that occurs in a kainic acid (KA) mice experimental model. In fact, significant changes in the transcriptional activity of a total of 23 genes were found in the hippocampus of wild-type C57BL/6 mice after 12 h of KA treatment compared to untreated mice. Among the up-regulated genes, we found key factors involved in the extrinsic apoptotic pathway, such as tnf, fas and fasL, and also in caspase genes (caspase-4, caspase-8 and caspase-3). To discern the importance of the FasR/FasL pathway, mice lacking the functional Fas death receptor (lpr) were also treated with KA. After 24 h of neurotoxin treatment, lpr mice exhibited a reduced number of apoptotic positive cells, determined by the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) method in different regions of the hippocampus, when compared to wild-type mice. In addition, treatment of lpr mice with KA did not produce significant changes in the transcriptional activity of genes related to apoptosis in the hippocampus, either in the fas and fas ligand genes or in caspase-4 and caspase-8 and the executioner caspase-3 genes, as occurred in wild-type C57BL/6 mice. Thus, these data provide direct evidence that Fas signalling plays a key role in the induction of apoptosis in the hippocampus following KA treatment, making the inhibition of the death receptor pathway a potentially suitable target for excitotoxicity neuroprotection in neurological conditions such as epilepsy.Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CiberNed-Instituto de Salud Carlos III) and by grants fromMinisterio de Ciencia (MICINN, MINECO) SAF2009-08233 and SAF2012-34177 and Fundación Ramón Areces to JJL. Grant 2009/SGR00853 from the Generalitat de Catalunya (Autonomous Government of Catalonia) and grants BFU2010-19119/BFI to CA, SAF2011-23631 to AC, and SAF2012-39852-C02-01 to MP from the Spanish Ministerio de Ciencia (MICINN, MINECO) also supported the study. Grant 0177594 from CONACYT (Mexico)Peer Reviewe

Embryonic Neural Stem Cell Differentiation to Aldynoglia Induced by Olfactory Bulb Ensheathing Cell-Conditioned Medium

Although the relevance of glial cells in regulating brain activity was predicted by Ramon y Cajal more than a century ago (García-Marín et al., 2007), it was not until almost fifty years ago that initial descriptions of a close functional relationship between neuroglia and neuronal perikarya (Hyden, 1962) or axonal processes (Blunt et al, 1965) began to reveal that neurons and glial cells operate as functional units in the central nervous system (CNS). However, this functional interaction has only been more carefully studied and analysed in the last few decades, generating a substantial increase in research on the roles of neuron– glia interactions in the control of brain function. Glial cells have subsequently been implicated in many functions, including: guiding the migration of neurons in early development, axonal guidance and being responsible for their integrity, forming the necessary scaffold for neuronal architecture and neural protection and proliferation by trophic effects, modulating neurodegenerative processes, and also being critical participants in synaptic transmission, and key regulators of neurotransmitter release..

Epigenetic mechanisms underlying cognitive impairment and Alzheimer disease hallmarks in 5XFAD mice

5XFAD is an early-onset mouse transgenic model of Alzheimer disease (AD). Up to now there are no studies that focus on the epigenetic changes produced as a result of Aß-42 accumulation and the possible involvement in the different expression of related AD-genes. Under several behavioral and cognition test, we found impairment in memory and psychoemotional changes in female 5XFAD mice in reference to wild type that worsens with age. Cognitive changes correlated with alterations on protein level analysis and gene expression of markers related with tau aberrant phosphorylation, amyloidogenic pathway (APP, BACE1), Oxidative Stress (iNOS, Aldh2) and inflammation (astrogliosis, TNF-¿ and IL-6); no changes were found in non-amyloidogenic pathway indicators such as ADAM10. Epigenetics changes as higher CpG methylation and transcriptional changes in DNA methyltransferases (DNMTs) family were found. Dnmt1 increases in younger 5XFAD and Dnmt3a and b high levels in the oldest transgenic mice. Similar pattern was found with histone methyltransferases such as Jarid1a andG9a. Histone deacetylase 2 (Hdac2) or Sirt6, both related with cognition and memory, presented a similar pattern. Taken together, these hallmarks presented by the 5XFAD model prompted its use in assessing different potential therapeutic interventions based on epigenetic targets after earlier amyloid deposition.This study was supported by Spanish MINECO, and the European Regional Development Funds (SAF-2012- 39852, BFU2013-48822-R and CSD2010-00045). CGF, AC, and MP belong to 2014 SGR 525; and SS and CS to 2014 SGR 625.Peer Reviewe

Alpha-Secretase ADAM10 Regulation: Insights into Alzheimer's Disease Treatment

ADAM (a disintegrin and metalloproteinase) is a family of widely expressed, transmembrane and secreted proteins of approximately 750 amino acids in length with functions in cell adhesion and proteolytic processing of the ectodomains of diverse cell-surface receptors and signaling molecules. ADAM10 is the main α-secretase that cleaves APP (amyloid precursor protein) in the non-amyloidogenic pathway inhibiting the formation of β-amyloid peptide, whose accumulation and aggregation leads to neuronal degeneration in Alzheimer's disease (AD). ADAM10 is a membrane-anchored metalloprotease that sheds, besides APP, the ectodomain of a large variety of cell-surface proteins including cytokines, adhesion molecules and notch. APP cleavage by ADAM10 results in the production of an APP-derived fragment, sAPPα, which is neuroprotective. As increased ADAM10 activity protects the brain from β-amyloid deposition in AD, this strategy has been proved to be effective in treating neurodegenerative diseases, including AD. Here, we describe the physiological mechanisms regulating ADAM10 expression at different levels, aiming to propose strategies for AD treatment. We report in this review on the physiological regulation of ADAM10 at the transcriptional level, by epigenetic factors, miRNAs and/or translational and post-translational levels. In addition, we describe the conditions that can change ADAM10 expression in vitro and in vivo, and discuss how this knowledge may help in AD treatment. Regulation of ADAM10 is achieved by multiple mechanisms that include transcriptional, translational and post-translational strategies, which we will summarize in this review

The black box of global aphasia: Neuroanatomical underpinnings of remission from acute global aphasia with preserved inner language function

Objective We studied an unusual case of global aphasia (GA) occurring after brain tumor removal and remitting one-month after surgery. After recovering, the patient reported on her experience during the episode, which suggested a partial preservation of language abilities (such as semantic processing) and the presence of inner speech (IS) despite a failure in overt speech production. Thus, we explored the role of IS and preserved language functions in the acute phase and investigated the neuroanatomical underpinnings of this severe breakdown in language processing. Method A neuropsychological and language assessment tapping into language production, comprehension, attention and working memory was carried out both before and three months after surgery. In the acute stage a simplified protocol was tailored to assess the limited language abilities and further explore patient's performance on different semantic tasks. The neuroanatomical dimension of these abrupt changes was provided by perioperative structural neuroimaging. Results Language and neuropsychological performance were normal/close to normal both before and three months after surgery. In the acute stage, the patient presented severe difficulties with comprehension, production and repetition, whereas she was able to correctly perform tasks that requested conceptual analysis and non-verbal operations. After recovering, the patient reported that she had been able to internally formulate her thoughts despite her overt phonological errors during the episode. Structural neuroimaging revealed that an extra-axial blood collection affected the middle frontal areas during the acute stage and that the white matter circuitry was left-lateralized before surgery. Conclusions We deemed that the global aphasia episode was produced by a combination of the post-operative extra-axial blood collection directly impacting left middle frontal areas and a left-lateralization of the arcuate and/or uncinated fasciculi before surgery. Additionally, we advocate for a comprehensive evaluation of linguistic function that includes the assessment of IS and non-expressive language functions in similar cases

Study of the transport of substances across the blood-brain barrier with the 8D3 anti-transferrin receptor antibody

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/128014Numerous strategies have been proposed to overcome the blood-brain barrier (BBB) and efficiently deliver therapeutic agents to the brain. One of these strategies consists of linking the pharmacologically active substance to a molecular vector that acts as a molecular Trojan Horse and is capable of crossing the BBB using a receptor-mediated transcellular transport system of the brain capillary endothelial cells (BCECs). The transferrin receptor (TfR) is related to a transcytosis process in these cells, and the 8D3 monoclonal antibody (mAb), directed against the mouse TfR, is able to induce a receptor response. Thus, the 8D3 antibody could be a potential molecular Trojan Horse to transport pharmacologically active substances across the BBB. On these bases, a series of experiments were performed where the 8D3 antibody was conjugated to different cargoes, the resulting constructs were administered in vivo to mice, and the distribution and intracellular mechanisms that these constructs undergo at the BBB were studied. Our results indicated a TfR-mediated and clathrin-dependent internalization process by which the 8D3-cargo constructs enters the BCEC. The resulting endocytic vesicles follow at least two different routes. On one hand, most vesicles enter intracellular processes of vesicular fusion and rearrangement in which the cargo is guided to late endosomes, multivesicular bodies or lysosomes. On the other hand, a small but not negligible percentage of the vesicles follow a different route in which they fuse with the abluminal membrane and open towards the basal lamina, indicating a potential route for the delivery of therapeutic substances. In this route, however, the 8D3−cargo remain fixed to the abluminal membrane, indicating that the 8D3 is maintained linked to the TfR, and the cargo does not go beyond the basal membrane. Altogether, different optimization approaches need to be developed for efficient drug delivery, but receptor-mediated transport (RMT) continues to be one of the most promising strategies to overcome the BBB

Surface functionalization of PLGA nanoparticles to increase transport across the BBB for Alzheimers disease

Alzheimers disease (AD) is a chronic neurodegenerative disorder that accounts for about 60% of all diagnosed cases of dementia worldwide. Although there are currently several drugs marketed for its treatment, none are capable of slowing down or stopping the progression of AD. The role of the blood-brain barrier (BBB) plays a key role in the design of a successful treatment for this neurodegenerative disease. Nanosized particles have been proposed as suitable drug delivery systems to overcome BBB with the purpose of increasing bioavailability of drugs in the brain. Biodegradable poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) have been particularly regarded as promising drug delivery systems as they can be surface-tailored with functionalized molecules for site-specific targeting. In this review, a thorough discussion about the most recent functionalization strategies based on PLGA-NPs for AD and their mechanisms of action is provided, together with a description of AD pathogenesis and the role of the BBB in brain targeting.A.C. [Amanda Cano] acknowledges the support of the Spanish Ministry of Science, Innovation and Universities under the grant Juan de la Cierva (FJC2018-036012-I). Authors acknowledge the support of the Spanish Ministry of Economy and Competitiveness under the project SAF2017-84283-R; Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED, CB06/05/0024) and Portuguese Science and Technology Foundation (FCT) for the strategic fund (UIDB/04469/2020).info:eu-repo/semantics/publishedVersio

Endothelial-specific deficiency of megalin in the brain protects mice against high-fat diet challenge

Background: The increasing risk of obesity and diabetes among other metabolic disorders are the consequence of shifts in dietary patterns with high caloric-content food intake. We previously reported that megalin regulates energy homeostasis using blood-brain barrier (BBB) endothelial megalin-deficient (EMD) mice, since these animals developed obesity and metabolic syndrome upon normal chow diet administration. Obesity in mid-life appears to be related to greater dementia risk and represents an increasing global health issue. We demonstrated that EMD phenotype induced impaired learning ability and recognition memory, neurodegeneration, neuroinflammation, reduced neurogenesis, and mitochondrial deregulation associated with higher mitochondrial mass in cortical tissue

Involvement of JNK1 in neuronal polarization during brain development

The c-Jun N-terminal Kinases (JNKs) are a group of regulatory elements responsible for the control of a wide array of functions within the cell. In the central nervous system (CNS), JNKs are involved in neuronal polarization, starting from the cell division of neural stem cells and ending with their final positioning when migrating and maturing. This review will focus mostly on isoform JNK1, the foremost contributor of total JNK activity in the CNS. Throughout the text, research from multiple groups will be summarized and discussed in order to describe the involvement of the JNKs in the different steps of neuronal polarization. The data presented support the idea that isoform JNK1 is highly relevant to the regulation of many of the processes that occur in neuronal development in the CNS

Trafficking of Gold Nanoparticles Coated with the 8D3 Anti-Transferrin Receptor Antibody at the Mouse Blood-Brain Barrier

Receptor-mediated transcytosis has been widely studied as a possible strategy to transport neurotherapeutics across the blood-brain barrier (BBB). Monoclonal antibodies directed against the transferrin receptor (TfR) have been proposed as potential carrier candidates. A better understanding of the mechanisms involved in their cellular uptake and intracellular trafficking is required and could critically contribute to the improvement of delivery methods. Accordingly, we studied here the trafficking of gold nanoparticles (AuNPs) coated with the 8D3 anti-transferrin receptor antibody at the mouse BBB. 8D3-AuNPs were intravenously administered to mice and allowed to recirculate for a range of times, from 10 min to 24 h, before brain extraction and analysis by transmission electron microscope techniques. Our results indicated a TfR-mediated and clathrin-dependent internalization process by which 8D3-AuNPs internalize individually in vesicles. These vesicles then follow at least two different routes. On one hand, most vesicles enter intracellular processes of vesicular fusion and rearrangement in which the AuNPs end up accumulating in late endosomes, multivesicular bodies or lysosomes, which present a high AuNP content. On the other hand, a small percentage of the vesicles follow a different route in which they fuse with the abluminal membrane and open to the basal membrane. In these cases, the 8D3-AuNPs remain attached to the abluminal membrane, which suggests an endosomal escape, but not dissociation from TfR. Altogether, although receptor-mediated transport continues to be one of the most promising strategies to overcome the BBB, different optimization approaches need to be developed for efficient drug delivery. Keywords: blood−brain barrier; drug delivery; electron microscopy; monoclonal antibodies; receptor-mediated transport; transferrin receptor