Role of the Transcription Factor CREB in the NMDA Receptor Antagonist-Induced Attention Deficits

This thesis is the result of a multidisciplinary approach which combines behavioral, biochemical and neurochemical assays to identify and delineate the molecular mechanisms involved in the control of attention. Blockade of prefrontocortical glutamate NMDAR is associated with attentional performance deficits as assessed in a task capable of measuring selective attention and response control such as the five choice serial reaction time (5-CSRT) task. I investigated whether phosphorylation of proteins linked to the PKA/CREB pathway in the prefrontal cortex (PFC) and in subcortical regions may be affected by NMDAR blockade. Pharmacological experiments using western blot and immunohistochemical techniques clearly demonstrated that increased CREB phosphorylation (p-CREB) in the PFC but not in subcortical regions may be associated to deficits in attention performance caused by the blockade of prefrontocortical NMDAR with the selective antagonist CPP. Attempts has been made to identify the intracellular pathways responsible for CPP-induced p-CREB changes by examining different protein kinases upstream to CREB such as protein kinase A (PKA), extracellular regulated protein kinases 1/2 (ERK1/2) and calcium/calmodulin kinase II (CaMKII). However, the precise role of these kinases in NMDAR antagonist induced changes in p-CREB is unclear and deserves further studies. The hypothesis that attention deficits induced by NMDAR blockade in the PFC might reflect excessive glutamate (GLU) release in the PFC was investigated by assessing the effects of intracortical CPP on attention, GLU release and p-CREB under basal conditions and in rats pre-treated with the mGlu2/3 receptor agonist LY379268. The results provide evidence that enhanced GLU release in the PFC and CREB phosphorylation are associated to attention deficit. As there are evidences that drug responses may be modulated by the behavioural state of animals, I evaluated the effect of blockade of NMDAR in the PFC on p-CREB in rats performing the 5-CSRT task. Intriguingly, I found that in these rats CPP-induced p-CREB in the PFC was decreased as opposed to the increase found in behaviourally naive rats at the same time point, suggesting that the direction of CPP-induced p-CREB changes critically depends on the behavioural state of animals. Moreover CPP-induced cognitive impairments were prevented by the intracortical administration of Sp-cAMP suggesting that the activation of the PKA/CREB cascade in the PFC is required for the correct performance of the task. In conclusion the present thesis support the role of CREB and provide new information on the mechanisms involved in the control of attention and executive functions associated with some neuropsychiatric disorders

From Osteoclast Differentiation to Osteonecrosis of the Jaw: Molecular and Clinical Insights

Bone physiology relies on the delicate balance between resorption and formation of its tissue. Bone resorption depends on a process called osteoclastogenesis in which bone-resorbing cells, i.e., osteoclasts, are produced by the differentiation of more undifferentiated progenitors and precursors. This process is governed by two main factors, monocyte colony-stimulating factor (M-CSF) and receptor activator of NFκB ligand (RANKL). While the former exerts a proliferating effect on progenitors/precursors, the latter triggers a differentiation effect on more mature cells of the same lineage. Bone homeostasis requires a perfect space–time coordination of the involved signals. When osteoclastogenesis is poorly balanced with the differentiation of the bone forming counterparts, i.e., osteoblasts, physiological bone remodelling can turn into a pathological state, causing the systematic disruption of bone tissue which results in osteopenia or osteolysis. Examples of these conditions are represented by osteoporosis, Paget’s disease, bone metastasis, and multiple myeloma. Therefore, drugs targeting osteoclastogenesis, such as bisphosphonates and an anti-RANKL monoclonal antibody, have been developed and are currently used in the treatment of such diseases. Despite their demonstrated therapeutic efficacy, these agents are unfortunately not devoid of side effects. In this regard, a condition called osteonecrosis of the jaw (ONJ) has been recently correlated with anti-resorptive therapy. In this review we will address the involvement of osteoclasts and osteoclast-related factors in the pathogenesis of ONJ. It is to be hoped that a better understanding of the biological mechanisms underlying bone remodelling will help in the design a medical therapeutic approach for ONJ as an alternative to surgical procedures.Bone physiology relies on the delicate balance between resorption and formation of its tissue. Bone resorption depends on a process called osteoclastogenesis in which bone-resorbing cells, i.e., osteoclasts, are produced by the differentiation of more undifferentiated progenitors and precursors. This process is governed by two main factors, monocyte colony-stimulating factor (M-CSF) and receptor activator of NFκB ligand (RANKL). While the former exerts a proliferating effect on progenitors/precursors, the latter triggers a differentiation effect on more mature cells of the same lineage. Bone homeostasis requires a perfect space–time coordination of the involved signals. When osteoclastogenesis is poorly balanced with the differentiation of the bone forming counterparts, i.e., osteoblasts, physiological bone remodelling can turn into a pathological state, causing the systematic disruption of bone tissue which results in osteopenia or osteolysis. Examples of these conditions are represented by osteoporosis, Paget’s disease, bone metastasis, and multiple myeloma. Therefore, drugs targeting osteoclastogenesis, such as bisphosphonates and an anti-RANKL monoclonal antibody, have been developed and are currently used in the treatment of such diseases. Despite their demonstrated therapeutic efficacy, these agents are unfortunately not devoid of side effects. In this regard, a condition called osteonecrosis of the jaw (ONJ) has been recently correlated with anti-resorptive therapy. In this review we will address the involvement of osteoclasts and osteoclast-related factors in the pathogenesis of ONJ. It is to be hoped that a better understanding of the biological mechanisms underlying bone remodelling will help in the design a medical therapeutic approach for ONJ as an alternative to surgical procedures

Immunization with the conjugate vaccine Vi-CRM197 against Salmonella Typhi induces Vi-specific mucosal and systemic immune responses in mice

AbstractTyphoid fever is a public health problem, especially among young children in developing countries. To address this need, a glycoconjugate vaccine Vi-CRM197, composed of the polysaccharide antigen Vi covalently conjugated to the non-toxic mutant of diphtheria toxin CRM197, is under development. Here, we assessed the antibody and cellular responses, both local and systemic, following subcutaneous injection of Vi-CRM197. The glycoconjugate elicited Vi-specific serum IgG titers significantly higher than unconjugated Vi, with prevalence of IgG1 that persisted for at least 60 days after immunization. Vi-specific IgG, but not IgA, were present in intestinal washes. Lymphocytes proliferation after restimulation with Vi-CRM197 was observed in spleen and mesenteric lymph nodes. These data confirm the immunogenicity of Vi-CRM197 and demonstrate that the vaccine-specific antibody and cellular immune responses are present also in the intestinal tract, thus strengthening the suitability of Vi-CRM197 as a promising candidate vaccine against Salmonella Typhi

A Whole-Brain Atlas of Inputs to Serotonergic Neurons of the Dorsal and Median Raphe Nuclei

SummaryThe serotonin system is proposed to regulate physiology and behavior and to underlie mood disorders; nevertheless, the circuitry controlling serotonergic neurons remains uncharacterized. We therefore generated a comprehensive whole-brain atlas defining the monosynaptic inputs onto forebrain-projecting serotonergic neurons of dorsal versus median raphe based on a genetically restricted transsynaptic retrograde tracing strategy. We identified discrete inputs onto serotonergic neurons from forebrain and brainstem neurons, with specific inputs from hypothalamus, cortex, basal ganglia, and midbrain, displaying a greater than anticipated complexity and diversity in cell-type-specific connectivity. We identified and functionally confirmed monosynaptic glutamatergic inputs from prefrontal cortex and lateral habenula onto serotonergic neurons as well as a direct GABAergic input from striatal projection neurons. In summary, our findings emphasize the role of hyperdirect inputs to serotonergic neurons. Cell-type-specific classification of connectivity patterns will allow for further functional analysis of the diverse but specific inputs that control serotonergic neurons during behavior

Lecturas en tensión en la escuela: un análisis de la voz narradora en “La larga risa de todos estos años”, de Rodolfo Fogwill

Lo que nos resultó más inquietante de este texto, es decir, lo que nos suscitó más preguntas y cuestionamientos (y ganas de poner este texto en juego en una clase de secundaria) es este efecto de sorpresa que se genera en lxs lectorxs cuando, en realidad, la voz narradora se había bien ocupado de que no tuviéramos anclaje textual alguno para atribuirle ningún género ¿Por qué lo leemos como una especie de revelación? ¿Qué es lo que nos lleva, entonces, a sorprendernos? ¿Qué sucedió en nuestra lectura para que ahora el mismo texto nos muestre que, de alguna manera, "nos quedamos cortxs" ante él?Eje 1: Cuerpos (in)disciplinados.Facultad de Humanidades y Ciencias de la Educació

Lecturas en tensión en la escuela: un análisis de la voz narradora en “La larga risa de todos estos años”, de Rodolfo Fogwill

Lo que nos resultó más inquietante de este texto, es decir, lo que nos suscitó más preguntas y cuestionamientos (y ganas de poner este texto en juego en una clase de secundaria) es este efecto de sorpresa que se genera en lxs lectorxs cuando, en realidad, la voz narradora se había bien ocupado de que no tuviéramos anclaje textual alguno para atribuirle ningún género ¿Por qué lo leemos como una especie de revelación? ¿Qué es lo que nos lleva, entonces, a sorprendernos? ¿Qué sucedió en nuestra lectura para que ahora el mismo texto nos muestre que, de alguna manera, "nos quedamos cortxs" ante él?Eje 1: Cuerpos (in)disciplinados.Facultad de Humanidades y Ciencias de la Educació