Developmental Neurobiology (Keays)

Department / Institute
Faculty of Biology
Subject area
Developmental Neurobiology
Project title
Modelling TUBB2A Associated Disease States with Cerebral Organoids
Name of supervisor
Prof. Dr. David Keays
Number of open positions
1
Language requirements
Proficiency in English
Academic requirements
4-year Bachelor's plus Master's Degree; at the time of application, the last final exam should have taken place during the past 4 years.
Project time plan
Full Doctoral Study Model: 36 or 48 months

Project description

This project will provide mechanistic insight into human brain malformations caused by mutations in a beta-tubulin gene, TUBB2A, by exploiting advanced human stem cell-based methods.The human cerebral cortex is one of the most complex biological structures in biology. Its development involves a carefully orchestrated sequence of events that can be divided into three major stages: i) the generation of neurons; ii) the migration of neurons from their place of birth into the developing cerebral cortex; and iii) and the maturation and differentiation of neurons forming functional circuits.

Cortical development is dependent on correctly functioning microtubules: dynamic, scaffold-like polymers composed of alpha- & beta-tubulin heterodimers. Microtubules generate the intracellular forces required for each major stage of cortical development: i) they form the mitotic spindle during cell division, facilitating the separation of sister chromatids; ii) they enable translocation of the nucleus and extension of the leading process during neuronal migration; iii) and microtubules polymers extend and maintain large and longstanding axons in mature neurons that enable connectivity with often distant regions of the brain.

TUBB2A encodes for a beta-tubulin protein. Different TUBB2A variants give rise to a spectrum of cortical brain malformations including microcephaly (reduced brain size) and lissencephaly (smooth or broadly convoluted cortical folds). The specific cellular mechanisms underlying cortical malformations are poorly understood. We hypothesise that TUBB2A mutations affect the correct assembly, stability and/or the dynamics of microtubule polymers which, in turn, perturbs correct neuronal proliferation, migration and/or differentiation during cortical development.

This project will investigate TUBB2A-related disease using human stem cells. We have obtained skin fibroblasts from individuals with cortical malformations harbouring TUBB2A mutations and these have been reprogrammed to induced pluripotent stem cells (iPSCs). We have additionally used CRISPR/Cas9 to ‘repair’ patient mutations back to wild-type sequence, generating suitable control lines to pinpoint the mutation-specific effects on cortical development.

The project will involve differentiation of patient and control iPSCs into 2D neuronal cultures to determine the effects of TUBB2A variants on microtubule biology and function. Furthermore, to characterise potential consequences of TUBB2A mutations on neurogenesis, neuronal migration, and cortical organisation, we will use patient and control iPSCs to generate cerebral organoids, 3D neuronal cultures that recapitulate early stages of human cortical development.

Interested students should contact Professor Keays via e-mail (david.keays@imp.ac.at)

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