Dr Joy Rathjen

 - Affiliate Investigator

Research focus: Understanding the maintenance and controlled differentiation of embryonic stem cells in culture

Dr Joy Rathjen has worked on understanding the maintenance of pluripotency and directing the differentiation of pluripotent cells in culture for nearly 20 years. Dr Rathjen has played a pioneering role in defining and understanding pluripotent cell states in culture, primarily through identification and characterisation in culture of embryonic primitive ectoderm (EPL cells), a population with similarities to embryonic epiblast and hESC.

These cells are the basis of directed differentiation methods that result in a homogenous population of neural ectoderm or, alternatively, a population restricted mesoderm and embryonic endoderm. This work was commercialized by Bresagen Ltd. and underpinned a 3 year research and development program (Cell Therapy Program) at the University of Adelaide. Further characterisation of EPL cell formation and subsequent differentiation has identified roles for amino acids, extracellular matrix, intracellular signaling pathways and cell-cell contact in the determination of the pluripotent cell state and lineage choice determination in mouse and human cells. 

Her technology underpinned the recognition and characterization of ‘autosomal Lyonisation’; the epigenetic remodeling of the genome that accompanies pluripotent cell differentiation. This work was conducted in collaboration with Prof. Dave Gilbert (Florida State). Dr Rathjen has demonstrated a long-term commitment to the development and use of ES cells in Australia. She has participated on a number of scientific boards, including the ASCC Scientific advisory board and is a founding member and chair of the University of Melbourne Stem Cell Interest Group, a group that works to raise the awareness of stem cell science in the Parkville precinct. 

In collaboration with Professor David Gardner (University of Melbourne), Dr Rathjen has been extending her characterization of pluripotent cells to include a detailed understanding of their interaction with the culture environment and the effect this has on their metabolism and function. Although a relatively recent collaboration, this interaction has bought together a novel combination of skills to address critical questions in hES cell biology. 

Her role as Associate Researcher in the Stem Cells Australia initiative will bring her in depth understanding of pluripotent cells and unique set of analytical skills to the initiative, and allow her to continue to work with Professor David Gardner to develop further insight into the impact of the extracellular and intracellular environment on hES cell quality and homogeneity in culture.