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

Memòria Digital UPC: Un recorrido por la memoria visual de la Universidad

Presentació per a XVIII Workshop REBIUN de Proyectos Digitales y VIII Jornadas de OS Repositorios realitzades el 25-27 de setembre del 2019En 2017 y como horizonte el 50º aniversario de la Universitat Politècnica de Catalunya a celebrar en 2020, el Servei de Biblioteques, Publicacions i Arxius (SBPA), impulsó un proyecto de tratamiento del fondo fotográfico considerado de interés para iniciar la recuperación de la memoria visual de la Universidad. Este proyecto, en explotación desde mayo del 2019 lleva el nombre de “Memòria Digital UPC”. Los objetivos de “Memòria Digital UPC” fueron: Identificar, organizar, describir, digitalizar y difundir, en acceso abierto, el patrimonio fotográfico de la UPC, mostrar la historia de la UPC a lo largo de los 50 años a través de imágenes, la creación de exposiciones virtuales que muestren la actividad académica, cultural y social de la Universidad y finalmente la creación de comunidad como proyecto abierto a la participación de cualquier persona de la UPC.Postprint (author's final draft

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

Adaptive plasticity in the hippocampus of young mice intermittently exposed to MDMA could be the origin of memory deficits.

(±)3,4-Methylenedioxymethamphetamine (MDMA) is a relatively selective dopaminergic neurotoxin in mice. This study was designed to evaluate whether MDMA exposure affects their recognition memory and hippocampal expression of plasticity markers. Mice were administered with increasing doses of MDMA once per week for 8 weeks (three times in 1 day, every 3 h) and killed 2 weeks (2w) or 3 months (3m) later. The treatment did not modify hippocampal tryptophan hydroxylase 2, a serotonergic indicator, but induced an initial reduction in dopaminergic markers in substantia nigra, which remained stable for at least 3 months. In parallel, MDMA produced a decrease in dopamine (DA) levels in the striatum at 2w, which were restored 3 months later, suggesting dopaminergic terminal regeneration (sprouting phenomenon). Moreover, recognition memory was assessed using the object recognition test. Young (2w) and mature (3m) adult mice exhibited impaired memory after 24-h but not after just 1-h retention interval. Two weeks after the treatment, animals showed constant levels of CREB but an increase in its phosphorylated form and in c-Fos expression. Brain-derived neurotrophic factor (BDNF) and especially Arc overexpression was sustained and long-lasting. We cannot rule out the absence of MDMA injury in the hippocampus being due to the generation of BDNF. The levels of NMDAR2B, PSD-95, and synaptophysin were unaffected. In conclusion, the young mice exposed to MDMA showed increased expression of early key markers of plasticity, which sometimes remained for 3 months, and suggests hippocampal maladaptive plasticity that could explain memory deficits evidenced here

Experimental Models for Aging and their Potential for Novel Drug Discovery

An interesting area of scientific research is the development of potential antiaging drugs. In order to pursue this goal, it is necessary to gather the specific knowledge about the adequate preclinical models that are available to evaluate the beneficial effects of new potential drugs. This review is focused on invertebrate and vertebrate preclinical models used to evaluate the efficacy of antiaging compounds, with the objective to extend life span and health span. Research and online content related to aging, antiaging drugs, experimental aging models is reviewed. Moreover, in this review, the main experimental preclinical models of organisms that have contributed to the research in the pharmacol-ogy of lifespan extension and the understanding of the aging process are discussed. Dietary restriction (DR) constitutes a common experimental process to extend life span in all organisms. Besides, classical antiaging drugs such as resveratrol, rapamycin and metformin denominated as DR mimetics are also discussed. Likewise, the main therapeutic targets of these drugs include sirtuins, IGF-1, and mTOR, all of them being modulated by DR. Advances in molecular biology have uncovered the potential molecular pathways involved in the aging process. Due to their characteristics, invertebrate models are mainly used for drug screening. The National Institute on Aging (NIA) developed the Interventions Testing Program (ITP). At the pre-clinical level, the ITP uses Heterogeneous mouse model (HET) which is probably the most suitable rodent model to study potential drugs against aging prevention. The accelerated-senescence mouse P8 is also a mammalian rodent model for aging research. However, when evaluating the effect of drugs on a preclinical level, the evaluation must be done in non-human primates since it is the mammalian specie closest to humans. Research is needed to investigate the impact of new potential drugs for the increase of human quality o

3,4-Methylenedioxymethamphetamine enhances kainic acid convulsive susceptibility

Abstract Kainic acid (KA) causes seizures and neuronal loss in the hippocampus. The present study investigated whether a recreational schedule of 3,4-methylenedioxymethamphetamine (MDMA) favours the development of a seizure state in a model of KA-induced epilepsy and potentiates the toxicity profile of KA (20 or 30 mg/kg). Adolescent male C57BL/6 mice received saline or MDMA t.i.d. (s.c. every 3 h), on 1 day a week, for 4 consecutive weeks. Twenty-four hours after the last MDMA exposure, the animals were injected with saline or KA (20 or 30 mg/kg). After this injection, we evaluated seizures, hippocampal neuronal cell death, microgliosis, astrogliosis, and calcium binding proteins. MDMA pretreatment, by itself, did not induce neuronal damage but increased seizure susceptibility in all KA treatments and potentiated the presence of Fluoro-Jade-positive cells in CA1. Furthermore, MDMA, like KA, significantly decreased parvalbumin levels in CA1 and dentate gyrus, where it potentiated the effects of KA. The amphetamine derivative also promoted a transient decrease in calbindin and calretinin levels, indicative of an abnormal neuronal discharge. In addition, treatment of cortical neurons with MDMA (1050 μM) for 6 or 48 h significantly increased basal Ca2 +, reduced basal Na+ levels and potentiated kainate response. These results indicate that MDMA potentiates KA-induced neurodegeneration and also increases KA seizure susceptibility. The mechanism proposed includes changes in Calcium Binding Proteins expression, probably due to the disruption of intracellular ionic homeostasis, or/and an indirect effect through glutamate release

JNK1 and JNK3: divergent functions in hippocampal metabolic-cognitive function

Background and aim: The appearance of alterations in normal metabolic activity has been increasingly considered a risk factor for the development of sporadic and late-onset neurodegenerative diseases. In this report, we induced chronic metabolic stress by feeding of a high-fat diet (HFD) in order to study its consequences in cognition. We also studied the effects of a loss of function of isoforms 1 and 3 of the c-Jun N-terminal Kinases (JNK), stress and cell death response elements. Methods: Animals were fed either with conventional chow or with HFD, from their weaning until their sacrifice at 9 months. Before sacrifice, body weight, intraperitoneal glucose and insulin tolerance test (IP-GTT and IP‑ITT) were performed to evaluate peripheral biometrics. Additionally, cognitive behavioral tests and analysis of spine density were performed to assess cognitive function. Molecular studies were carried out to confirm the effects of metabolic stressors in the hippocampus relative to cognitive loss. Results: Our studies demonstrated that HFD in Jnk3-/- lead to synergetic responses. Loss of function of JNK3 led to increased body weight, especially when exposed to an HFD and they had significantly decreased response to insulin. These mice also showed increased stress in the endoplasmic reticulum and diminished cognitive capacity. However, loss of function of JNK1 promoted normal or heightened energetic metabolism and preserved cognitive function even when chronically metabolically stressed. Conclusions: Downregulation of JNK3 does not seem to be a suitable target for the modulation of energetic-cognitive dysregulations while loss of function of JNK1 seems to promote a good metabolic-cognitive profile, just like resistance to the negative effects of chronic feeding with HFD.This work was supported by funds from the Spanish Ministerio de Economía y Competitividad (SAF2017-84283-R to AC), the Generalitat de Catalunya (2014SGR-525 to CA) and CIBERNED (Grant CB06/05/2004 to AC).S

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