BADIPS: The development of cell lines relevant for the discovery of new treatments for bipolar affective disorder

The aim of the BADIPS CRACK IT Challenge is to produce human induced pluripotent stem cells (iPSCs) derived from individuals with Bipolar disorder (BD) that could be used as a screening tool for the development of novel treatment options, reducing the dependence on animals and improving predictivity to the clinic.

The team led my Prof Andrew McIntosh from the University of Edinburgh will prioritise recruitment of five affected and five unaffected individuals from a single Scottish multiply-affected family with a highly-penetrant disease haplotype on chromosome 4p that co-segregates with mood disorder. This family contains 11 subjects with bipolar disorder (BD), 16 cases of major depression and more than ten suitable, and approximately age and sex-matched, controls. BD type 1 cases and controls will be interviewed using the SCID diagnostic assessment and will undergo a cognitive test battery to characterise the specific deficits in this particular family, compare them to larger samples of individuals with 'sporadic' BD and to identify potential clinical sources of heterogeneity that could be used to refine the selection of subjects/controls to those with a consistent disease phenotype.

Dermal fibroblasts will be obtained from five affected mutation carriers and five unaffected non-carriers from the family. Dermal fibroblast cell lines will be expanded, banked and then subjected to a QC testing regime before an aliquot is tested for iPS transformation and confirmation of pluripotency. The team will use non-integrating iPS technology to produce clonal iPS cell lines which will be transferred for validation and tissue banking. Neural progenitors (NPCs), cortical neurons and glia will then be generated and characterised using techniques including quantitative immuno-histochemistry, electrophysiology, glutamate uptake assays and neuronal morphology.

A sample of neuronal cells will be provided and RNA isolated for assessment of whole genome expression, and gene ontology will be performed.

Characterisation of these cells will provide a resource for the study and discovery of potential new therapies for Bipolar Disorder.

Full details about this CRACK IT Challenge can be found on the CRACK IT website.

The aim of the BADIPS CRACK IT Challenge was to produce human induced pluripotent stem cells (iPSCs) derived from individuals with Bipolar disorder (BD) that could be used as a screening tool for the development of novel treatment options, reducing the dependence on animals and improving predictivity to the clinic.

The team led by Professor Andrew McIntosh at the University of Edinburgh, in collaboration with the University of Cambridge and Roslin cells, has generated iPSCs from individuals with BD from a large multiply affected family and from unaffected family members as controls. During the project it was discovered that the genetic basis of illness in the affected family was not as straightforward as previously believed. At the start of the Challenge it was clear that a region of chromosome 4p segregated with the illness. However, as more family members were investigated, additional family members who were ill, but did not carry the 4p haplotype were identified. It is clear that there is a complex genetic component to BD, which contributes to illness within the family.

The iPSC lines were differentiated into neurons and characterised to demonstrate functionality. The iPSC-derived neurons fired action potentials in response to depolarisation and responded to neurotransmitters that act upon the major ligand-gated ion channels in the central nervous system (Figure 1 and 2). The iPSC-derived neurons were determined to harbour physiological properties consistent with neurons and were highly consistent with other reported properties from iPSC-derived neuronal studies (Bilican et al., 2014). No consistent differences in the physiological properties were observed across the lines examined.

The iPSC lines have been banked and are available to purchase through the European Bank of induced pluripotent Stem Cells (EBiSC). Details of the cell lines can be found online through the EBiSC catalogue https://cells.ebisc.org/.

Work is currently ongoing to further characterise the iPSC-derived neurons from affected and unaffected individuals, which includes characterising the electrophysiology, examining effects on gene expression and treating the cells with effective interventions currently used clinically.
 

 Figure 1. Action potentials recorded from iPSC-derived neurons in response to depolarisation. Representative traces from affected and unaffected individuals.
 

Figure 2. HiPSC-derived neurons respond to neurotransmitters: (A) AMPA (100 μM); (B) NMDA (100 μM) in the presence of glycine; (C) GABA (100 μM); (D) Post-synaptic current that resembles AMPA-ergic activity. Representative traces from affected and unaffected individuals.  

Cleary EM et al. (2016). Improved PCR based methods for detecting C9orf72 hexanucleotide repeat expansions. Molecular and cellular probes, 30 (4), pp. 218-24. DOI: 10.1016/j.mcp.2016.06.001.

Livesey MR et al. (2016). Maturation and electrophysiological properties of human pluripotent stem cell-derived oligodendrocytes. Stem cells (Dayton, Ohio), 34 (4), pp. 1040-53. DOI: 10.1002/stem.2273.

Livesey MR et al. (2016). Functional properties of in vitro excitatory cortical neurons derived from human pluripotent stem cells. The Journal of Physiology, 594 (22), pp. 6573-6582. DOI: 10.1113/JP270660.

Walker RM et al. (2016). DNA methylation in a Scottish family multiply affected by bipolar disorder and major depressive disorder. Clinical epigenetics, pp. 5. DOI: 10.1186/s13148-016-0171-z.