Non-Coding RNA Explosion: Novel Implications in Neurotrophin Biology

Research project

Description

Neurotrophins (NT) (BDNF, NGF and NT sensu stricto) are growth factors that control development, differentiation, synaptic plasticity and survival of several types of neuronal and glial cells in the embryonic and adult central nervous system and sensory organs. NT binding to specific tyrosine kinase receptors (TRK) and to a pan-neurotrophinic receptor (p75NTR) activates a series of events that, mediated by intracellular signal transduction pathways (e.g. MAPK/ERK, PLCg and PI3K), modify cytoplasmatic and nuclear proteins. Neurodegenerative diseases (ND) represent a heterogeneous group of disorders characterized by increasing alterations in neuronal differentiation, structure and function, leading to cell death. Alteration of NT levels and activity in NDs represents a diagnostic marker of cognitive decline even in absence of neurodegenerative and psychopathologic symptoms. Implication of NTs in the development of neuronal pathologies like Alzheimer’s disease (AD), prion disease and depression, makes these neurotrophic factors key elements in the generation of therapies for neuronal and psychiatric physiopathologies. Beyond genetic predisposition and vulnerability, stress (e.g. thermic, psycho-social and nutritional) is one of the major causes of mental and neuronal dysfunctions that involve NTs. Indeed, NTs play a role in learning, memory and expression of behaviours linked to anxiety, but they are also involved in modulating the physiological and behavioural response to chronic stress conditions. For example, NTs interact with the Apolipoprotein E (ApoE), a fundamental protein in lipid metabolism that is responsible of cholesterol traffickin. Total levels and membrane distribution of cholesterol affect neuronal functions and enzymatic activity of beta-amyloid proteins.

Based on the NT role in development and physiology of the nervous system, the present project aims at extending our knowledge on the genetic factors and the functional processes of the NT molecular pathways, with emphasis on the relationships among NT and stress, and on the characterization of new molecules upstream and downstream NTs. One main focus of the project will be concerned with the identification of noncoding RNAs (ncRNA) that regulate, or are regulated by, NTs and NT receptors (NTR). ncRNAs are a new class of regulatory molecules that have been shown to be involved in almost all biological phenomena, including development and physiology of the nervous system. To this respect, the project consists of a multidisciplinary study based on bioinformatic, molecular, genetic, biochemical and behavioural approaches, with the goal to acquire new insights on the genetic regulatory networks and on the functions exerted by NT and NT receptors during the correct development and functioning of different embryonic and adult cerebral regions, and in conditions of thermal, social and nutritional stress. The Research Units involved in the project possess diversified expertise both in terms of experimental tools and model systems. Indeed, a distinctive feature of this research proposal is the use of cells, mouse and zebrafish. The latter is a powerful model organism to complement mouse data on human illnesse, both by virtue of many available experimental approaches and a high degree of functional conservationetween zebrafish genes and their human homologs. In particular, structural low complexity of the zebrafish is an advantage for understanding pathological and physiological mechanisms, something hard to achieve in superior organisms due to way more complex neuronal networks. Comparison of the cellular and murine phenotype physiopathology with that of the zebrafish creates an advanced instrument to identify potentially effective therapeutic strategies. The possibility to accelerate the experiments in vertebrates by using both mouse and zebrafish is supported by the evidence that many pathologies can be cured in mouse but not in man. Moreover, fish metabolism could be closer to man than mouse. For example, in the case of ND vs stress studies, while mouse and rat use corticosteron as main stress hormone, fish and man use cortisol. In summary, the main purpose of the present project is to study the molecular, cellular and behavioural phenotype of NTs and NTRs in cells, zebrafish and mouse, with emphasis on the relationships of these molecules with stress, ncRNAs and NDs. In particular, bioinformatic, regulatory and functional characterization of zebrafish NTs and NTRs will allow to develop a new model organisms for the study of NDs and stress.

To this aim, the objectives of this research proposal can be summarized as following: 1) description of the NT and NTR transcriptional profiles in space and time in the embryonic and adult nervous system (zebrafish), for integrating and extending current knowledge limited to BDNF and some receptors; 2) characterization of the embryonic and adult phenotype generated by inactivation of protein sysnthesis of NTs and NTRs in knockdown and mutant embryos (at the level of behaviour, biochemistry,genetics and cell biology) (zebrafish); 3) identification of new genes (codifying and not codifying) acting upstream or downstream of NTs and NTRs by means of bioinformatic analysis of genome and transcriptome (zebrafish), and study of their function during embryonic development and in the adult brain (cells, zebrafish, mouse); 4) production of new transgenic lines under the control of NT and NTR promoters as tools for the analysis of cell biology in vivo by confocal microscopy (zebrafish); 5) study of the short- and long-term relationships between NTs and thermal, nutritional (hypercholesterolemy and aging) and psycho-social (exploration, predation, photoperiod) stress (at the level of behaviour, biochemistry, genetics, epigenetics and cell biology) (cells, zebrafish, mouse). In the frame of this final objective, we will verify the potential role that the new factors identified through the bioinformatic analysis of genome and differential transcriptome exert in stress response modulation (cells, zebrafish, mouse), and we will examine the relationships among NTs, hypercholesterolemy and aging (cells and mouse).

Altogether, we expect that the spectrum of approaches and objectives planned in this study will be instrumental to the development of new model systems for the study of NTs (zebrafish morphants, mutants and transgenic lines) and, most importantly, to the improved understanding of the role played by NTs during embryonic development and adult brain physiology, with particular attention to the biomedical impact in terms of diagnosis and treatment of neurological diseases with neurodegenerative and/or psychological traits.
StatusActive
Effective start/end date1/1/12 → …

Funding

  • MIUR - FIRB

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Untranslated RNA
Explosions
Zebrafish
Nerve Growth Factor Receptors
Computational Biology
Neurodegenerative Diseases
Cell Biology
Hot Temperature
Phenotype
Nervous System Physiological Phenomena
Biochemistry
Embryonic Development
Fishes
Research Design
Cholesterol
Genome
Pathology
Brain
trkB Receptor
Prion Diseases