Research topics

Sub-cellular functional dynamics

Neuronal differentiation requires the function of the secretory pathway and the cytoskeleton in neurons and glia. In this context, it is fundamental to understand how the dynamical structures of the secretory pathway and the cytoskeleton are organized into different cell types of the nervous system, and how this organization determines neuronal function or dysfunction. We have developed methodologies to analyze subcellular components in neuronal cultures and astrocytes at high spatio-temporal resolution and in neuropathological conditions where the organelles and cytoskeletal functions are dramatically affected. We now combine the manipulation of gene expression in brain cell culture with the use of genetically modified organisms to study: (i) the morpho-functional organization of the endoplasmic reticulum and the consequences of altering its structure in protein trafficking and disease human (XBP-1 / ATF4 deficient), (ii) the role of recently identified proteins (Marlin1) in the organization of the cytoskeleton, (iii) the spacetime activation of signaling molecules downstream of the cell adhesion receptors that govern changes in astrocytes and neuronal morphology during neurodegeneration and injury. This strategy provides a quantitative view of subcellular dynamic structures and their implications.

S. Härtel, A. Couve, M. Concha, C. Hetz, J. Sierralta y P.Olguín

Cell identity and morphology

The morpho-functional characteristics of differentiated neurons define the basic structure on which their connectivity is established. These characteristics determine how electrical signals are formed to represent simple elements of cell-cell communication and integrate them into sophisticated computational devices. Neural morphogenesis is intimately linked to the control of cell specification and differentiation. A central question is how gene expression determines morphofunctional characteristics during the development and life of neurons. We have combined fluorescent microscopy and exogenous expression in Drosophila (RNAi in small groups of neurons), mice (siRNA delivered by in utero electroporation to the developing cortex), and zebrafish (brain electroporation of morpholinos in embryos) to understand genetic mechanisms involved in the control of neuronal morphology. Now we combine these experimental models with electrophysiology and tools to quantify the structural characteristics of cells and neural networks to study the role of: (i) transcriptional control by complex chromatin remodeling in the acquisition and maintenance of neuronal morphology (REST / NRSF and CoREST), and (ii) new genes identified by genetic probes in Drosophila and zebrafish, and candidate molecules that participate in cytoskeletal dynamics during neuronal morpho-functionality (Marlin1). This strategy provides a comparative vision to dissect the role of conserved genes in the establishment of neuronal form and connectivity.

M. Concha, J. Sierralta, C. Hetz, S. Hartel y P. Olguín

Supra-cellular and circuit development

The supra-cellular transformation of brain morphogenesis involves the reorganization of multicellular aggregates into nuclei and layers, and the migration of axonal growth cones to establish connectivity. How this is achieved in vivo is still unknown. It is fundamental to understand how the activity of genes translates into the morphogenesis of the brain, and how the acquisition of new states of supra-cellular organization and connectivity, in turn, influence brain patterns and function. We address these questions using transgenic fish, genetic approaches, organotypic hippocampal cultures, 3D confocal visualization in vivo and neuronal morpho-functionality analysis, to study: (i) cellular mechanisms that control changes in adhesion, traction and polarity that lead to cell migration, the formation of cell layers and brain nuclei, and wound healing, (ii) the genetic and morphogenetic mechanisms that guide axonal growth cones and establish neuronal connectivity in vivo, centered in Wnt / PCP, FGF, chemokines, Robo / Slit and neurogenesis, and (iii) the dynamic configuration and functional correlation of neuronal circuits using optogenetic probes and electrophysiology in vivo. This strategy provides a contextual view of the mechanisms that guide the shape, structure, and development of neural circuits, revealing the general principles of organogenesis and brain function.

S. Hartel, A. Couve, M. Concha, J. Sierralta, M Kukuljan, JL Valdes

Plasticity and behavior

The synaptic plasticity of the hippocampus is a response associated with learning and memory and involves lasting modifications in the efficacy of synaptic transmission. Cytoplasmic and nuclear post-synaptic Ca2 + signals are necessary for long-term potentiation (LTP), which unleashes signaling cascades that activate transcription regulators and promote the expression of genes to maintain synaptic plasticity over long periods and alter neuronal assemblages. In this context, an essential question is how genetic interactions and signaling pathways control long-term memory. We have established methodologies to study the role of ryanodine receptors (RyR) dependent on Ca2 + signals in hippocampal LTP and behavior (labyrinths, object recognition and contextual fear conditioning). By combining these approaches with cellular and molecular biology, live cell imaging and electrophysiology (single channel studies in bilayers, high density electrophysiology in free-moving animals) we studied: (i) the effect of RyR activity on the expression of mRNA and protein-related plasticity and the role of Ca2 + signals generated by RyR in LTP (through pharmacology, delivery within hippocampal antisense nucleotides or shRNAs), (ii) learning effect, neuromodulators , and the modulators of RyRs in the dynamics of the assembly of neurons of the hippocampus, and (iii) their behavioral correlates.

A. Couve, C. Hetz, C Hidalgo

Systems neuroscience

Although most of the paradigms used to examine the neural mechanisms of cognitive functions have used simple and controlled stimuli, the responses of neurons to complex and more ecological situations are substantially different. Given that current models of functional organization fail to predict neuronal activity in more realistic experimental conditions, it is essential to examine, compare and model the neuronal activity of animals and humans involved in more ecological paradigms of experimental behavior and classic psychiatric disorders. We now examine neuronal activity by recording with single or multiple units, local field potentials and electroencephalographic recordings in (i) goal-directed behavior or (ii) natural behavior. We develop new analytical and statistical tools for signal processing and propose new models to account for "top-down" mechanisms in cognitive function.

S. Hartel, P Maldonado, H Silva, P Délano

Applied Mathematics and Biomedical Informatics

A deeper understanding of the architectural and functional principles of neuronal processes, from sub-cellular to supra-cellular levels, as well as the decoding of communication with physiological and behavioral patterns requires a transdisciplinary approach. Biophysics and applied mathematics in combination with advanced imaging and computer science foster an integrated view to study the dynamic design of biological structures and their functional patterns. The main objective is to discover new neural processes based on mathematical models that reveal morpho-functional principles of the organization in multiple scales. These tools allow the study of the morpho-topological organization patterns of neurons in 2 / 3D and colocalization in specific subcellular compartments. BNI encourages new approaches to: (i) localize / track proteins within subcellular organelles, (ii) study dendritic structure and axonal wiring (iii) model cellular and supra-cellular descriptors for the formation of multi-cellular rosettes based on equations of partial derivatives, (iv) the elaboration of statistics to study spike trains in multiple registers, (v) modeling neuronal assemblies to account for the activity during natural behaviors, and (vi) applying the mathematical tools for the image based on tele-analysis in clinical research and diagnostic medicine.

S. Hartel, P Maldonado, H Silva, A. Couve, M. Concha, J. Sierralta, P Délano,

Neural dysfunction and pharmacological targets

This cross-platform promotes an in vivo genetic/pharmacological/functional approach focused on assessing the role of genes related to common diseases in cellular processes that lead to neuronal connectivity and synapse formation. The alteration of these processes produces pathological phenotypes that affect neuronal functionality. The main objective of this platform is to develop knowledge, skills and technological approaches to achieve a better understanding of the mechanisms by which the genes related to diseases affect common molecular, physiological and cellular processes involved in neuropathological conditions, receiving scientific contributions from each of them. the research lines carried out at BNI. Therefore, we implemented disease models to mimic the conditions associated with human pathologies, including transgenic mice, gene therapy, and cell biology approaches, in addition to human studies, to discover pathological aspects related to: (i) the disease of Parkinson, (ii) Alzheimer's disease, (iii) nerve damage / regeneration and lateral amyotrophic sclerosis, (iv) Creutzfeldt-Jakob disease (CJD), and (v) epigenetics by characterizing short-term effects and long-term metabolic insults that occur at birth. We define the consequences of genetic manipulation of the disease model and identify new targets for pharmacological interventions. The scientific objectives benefit from mathematical analysis to model complex traits related to neuronal dysfunction.

S. Hartel, P Maldonado, J.Matamala

Clinical research and creation of new capabilities

The environment and connectivity of BNI offers a rich range of clinical research opportunities in Neuroscience, based on access to patients, samples, reliable records and motivated doctors. Previously, these opportunities have not achieved the expected development in Chile due to the dispersion of resources, lack of effective channels of interaction of physicians with scientific management structures and limited access to advanced technology. A central objective of BNI is the development and consolidation of clinical research and capacity building in the study of neurological and psychiatric pathologies. BNI provides platforms to solve the mentioned deficits by establishing a program focused on the training of scientists and clinical specialists with international competition standards and by defining specific projects, including: (i) development of diagnostic tools such as molecular markers in CJD and genetic / molecular markers for early prediction in anti-depressant treatments, (ii) therapeutic approaches such as gene therapy and small molecules in ALS and Parkinson's, (iii) genetic comparison of patients with bipolar disorders, and (iv) ) autistic spectrum and alterations of neural development.

J.Matamala, A. Couve, M. Concha, C. Hetz, JL Valdes

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