The Sullivan Group
The Sullivan laboratory interests are to gain a basic understanding of endoderm and mesoderm biology whilst developing novel methodologies.
The research areas that we are exploring within the Centre include understanding differentiation – this will provide important insight into the derivation of mature functional cell types from human pluripotent stem cells (hPSCs), in addition to providing tools for interrogation of disease/ toxicology models. To enable this we have been developing both 3D hepatic and adipose organoid models.
Over the year we have further refined our small molecule approach originally designed to generated hepatocytes in 2D, (doi.org/10.1016/j.stemcr.2015.04.001) to produce 3D scalable liver organoids. We have performed a battery of functional assays to demonstrate functional equivalence to primary tissue for example the production of vitamin K dependent coagulation factors and Phase I and II drug metabolism. We have conducted single cell RNAseq analysis demonstrating the presence of both parenchymal (hepatocytes and cholangiocytes) and non-parenchymal cells types (Stellate, Kupffer and liver sinusoidal endothelium). Another feature of the organoids is that they display enhanced function and longevity as compared to their 2D counterparts being maintained in culture for over 100 days. Interestingly, the liver organoids are vascularised, this being the first example of de novo vascularization described. A drawback of current hepatic organoid approaches is the reliance of extracellular matrix, which is a major bottleneck with respect to scaling i.e. generated in the 10´s to 100´s, here we can mass produce hepatic organoids at the 100,000´s to millions (manuscript in preparation).
In parallel, we have developed methodologies to produce adipose tissue. We have assessed different sources of hPSC derived mesenchymal stem cells (MSCs) for their ability to produce adipocytes. We have now developed robust methods to produce expandable neural crest cells, which have been directed to peripheral neurons. This neural crest population can be differentiated towards a MSC population. We have now established a rapid protocol to generate neural crest derived MSCs that are capable of tri-lineage differentiation. This MSC population is expandable and can be cryopreserved. Using the neural crest derived MSCs, we have developed an optimised procedure to produce white adipocytes. This white fat population expresses key markers such as PPAR2, FABP4 and Perilipin etc. Importantly, the white adipocytes can accumulate fat droplets over time. We have recently initiated benchmarking of the hiPSC derived white fat against human primary material.
- Scarfe L, Brillant N, Kumar JD, Ali N, Alrumayh A, Amali M, Barbellion S and et al. Pre-clinical imaging methods for assessing the safety and efficacy of regenerative medicine therapies. Nature Regenerative Medicine. 2017: Manuscript in Press/ Accepted.
- Gamal W, Treskes P, Chesne CG, Samuel K, Sullivan GJ, Siller R, Srsen V, Underwood I, Smith S, Hayes PC, Plevris JN, Bagnaninchi PO and Nelson LJ. Low-dose acetaminophen induces early disruption of cell-cell tight junctions in human hepatic cells and mouse liver. Scientific Reports. 2017:DOI: 10.1038/srep37541.
- Siller R, Naumovska E, Mathapati S, Lycke M and Sullivan GJ*. Development of a rapid screen for the endodermal differentiation potential of human pluripotent stem cell lines. Scientific Reports. 2016:DOI: 10.1038/srep37178. (*corresponding author).
- Siller R, Greenhough S, Naumovska E and Sullivan GJ*. Small molecule driven hepatocyte differentiation of human pluripotent stem cells. Stem Cell Reports. 2015: 4:939-952. (*corresponding author).
- Siller R, Greenhough S, Park IH and Sullivan GJ*. Modelling human disease with pluripotent stem cells. Current Gene Therapy. 2013: 13:99-110. (*corresponding author).