Sistema ETD

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Tesi etd-11202015-180811

Tipo di tesi
Tesi di laurea magistrale
MiRNA and mRNA expression during in vitro corticogeness
Corso di studi
relatore Dott. Cremisi, Federico
Parole chiave
  • corticogenesis
  • miRNA
  • neural induction
  • 46C
  • cell cultures
  • in vitro
  • cortical layers
Data inizio appello
Data di rilascio
Riassunto analitico
Out of the structures of the central nervous system (CNS), the cortex is the laminar surface of the telencephalon, the most anterior part of the forebrain; in humans represents up to 80% of the brain mass and it is characterised by a laminar structure composed of six layers generated in an inside-out pattern; cortical pyramidal neurons are all generated by neural progenitors, which experience a restriction of fate potential in time. Each layer is composed of a different neurons subtypes, defined by a specific combination of morphology, connectivity and specific molecular marker expression. Due to the histological, cellular and molecular complexity of the developing cortex, reductionist approaches have begun to be exploited to study the cortex development, establishing in vitro protocols to recreate corticogenesis on a petri dish.
It is know that the double inhibition of BMP and Wnt pathways in ES cells growing in a chemically defined minimal medium determines the acquisition of a rostral and neural fate. I refined the in vitro protocol developed by Bertacchi and colleagues (Bertacchi et al, 2015) by studying the effect of the retainment of the BMP and Wnt double inhibition until the commitment of neural progenitors or until mid-corticogenesis. The eventual differences of A/P patterning and the effect on the upper layer neurons production were analysed.
Neural progenitors experience a restriction of fate potential during corticogenesis: this fate restriction is dependent on intrinsic and extrinsic signals. I studied this progression in isolated progenitors, without any morphogen or mature neuron feedback: this allowed us to study the internal clock of neural progenitors, allowing only intrinsic pathways to determine an effect on them.
During cortical development, in neurons and progenitors there is a precise transcriptional and post-transcriptional regulation of layer specific proteins; this tight regulation have a crucial role in progenitors vitality and proliferation, but also the migration of differentiating cells, the production of specific cortical layers, cell branch formation and neuronal plasticity. With the aid of transgenic cell lines, the expression pattern of the mRNA of cortical layers marker genes have been studied in populations of mature neuron or progenitors and confronted with the time of onset of the protein synthesis. Moreover, with the deep sequencing of miRNA expression we could study the effect of miRNA-mediated post-transcriptional regulation and miRNAs that define a signature of progenitors and mature neurons.