Abstract
ZNF804A has recently been identified as a disease candidate gene for several severe neuropsychiatric disorders including bipolar disorder, schizophrenia and autism. Schizophrenia is known to share several clinical, genetic, pathophysiological, neuroanatomical and cognitive features with bipolar disorder, and thus ZNF804A may represent a useful target for investigating the common mechanisms underpinning these diseases. The latest advances in stem cell research have provided a wide variety of cellular models for studying these mechanisms in cultures of human neurons. One of these lines, a conditionally immortalised, cortically derived human neural progenitor cell (NPC) line (CTX0E16), offers a valuable tool for studying ZNF804A in human cortical neurons.The primary aims of the current investigation were to characterise neurons derived from the CTX0E16 NPC line and to subsequently employ this line in conjunction with other neuronal models in the study of ZNF804A expression, subcellular localisation and biological function, specifically focusing on its potential impact on neuronal morphology. To this end, neuronal cultures differentiated from the CTX0E16 cell line were characterised using a broad set of techniques. These cells were shown to predominately adopt a glutamatergic fate, and demonstrated the morphology, functional responses, synaptic expression and electrophysiological characteristics consistent with immature cortical pyramidal neurons. When examined in human neurons, ZNF804A was shown to be distributed throughout the neuron and demonstrated a novel distribution at putative synapses. ZNF804A was also located within the nucleus of both NPCs and neurons. Interestingly, this pattern changed as NPCs terminally differentiated into excitatory neurons. Moreover, in mature neurons, the presence of ZNF804A within the nucleus was modulated by activity-dependent stimulation. siRNA-mediated knockdown of ZNF804A revealed a role for this protein in early neurite outgrowth, an effect potentially mediated by neuroligin 4x. Knockdown of the rodent homologue, Zfp804A, further revealed a role in the maintenance and plasticity of dendritic spines in mature neurons. Collectively, these data show that the CTX0E16 cell line provides a useful model of human cortical neuron development and disease, and that ZNF804A plays a role in the development, maintenance and plasticity of key aspects of pyramidal neuron morphology. As alterations in these factors are thought to be central to the pathophysiology of schizophrenia and bipolar disorder, it is thus possible that ZNF804A represents a common risk factor that contributes to the cellular disturbances in these diseases.
| Date of Award | 2017 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Deepak Srivastava (Supervisor) & Jack Price (Supervisor) |