Current Projects

Project 1 Stem cells and intestinal epithelial differentiation

Dr Helen Abud, Ms Franca Casagranda

The intestinal epithelium or bowel lining is a regenerative tissue that is constantly renewed throughout life via a small population of stem cells. We are interested in how growth and differentiation of intestinal epithelial cells is regulated and how the balance between cell proliferation, cell differentiation and cell death is normally established and maintained in these cells. We are studying the contribution of different molecules to the establishment of the intestinal epithelium and the stem cell niche using immunohistochemistry and qPCR. Functional analysis is performed in intestinal organ culture where specific growth factors and inhibitors can be added. We are also investigating how potential cancer-causing genes may disrupt the biology of epithelial cells by introducing expression constructs into the epithelial cell layer of gut explants in organ culture. We also examine tissue from genetically manipulated mice containing specific mutations. This project combines molecular techniques (construct preparation, expression analysis) immunohistochemistry, embryonic gut culture and transgenic and conditional knockout mouse models.

Project 2 APC and the initiation of colorectal cancer

Dr Helen Abud, Ms Franca Casagranda

Colorectal carcinomas arise by a series of acquired genetic changes and progress via a sequence of distinct pathological stages. Mutations in the adenomatous polyposis coli (APC) gene are found in the early stages of around 80% of sporadic human colorectal tumours. Despite considerable evidence that mutation of APC is an early event in the progression of cancer, the precise effects of APC mutation on the behaviour of normal intestinal epithelial cells is unknown. We use an innovative mouse intestinal organ culture system where we can introduce mutations in APC that mimic those found in human tumours. This project will study the consequences of APC mutation on the biology of these cells using organ culture, conditional mouse models, immunohistochemistry and qPCR.

Project 3 Role of cytoskeletal elements in stem cell differentiation

Dr Gary Hime (Melbourne University) and Dr Helen Abud

Regenerative tissues are renewed from small populations of undifferentiated stem cells. The stem cell niche hypothesis concludes that when stem cells divide into two daughter cells they find themselves in different environments and this affects whether they remain as stem cells or differentiate. We are interested in studying molecules that affect polarity of stem cells and affect the plane of cell division and hence may determine whether daughter cells remain in the niche. This project will combine genetics in Drosophila and immunohistochemistry in both Drosophila and mouse organs to examine cytoskeletal and polarization molecules in stem cell populations.

Project 4 Genetic control of embryonic stem cell differentiation along endoderm/intestinal cell lineage.

Dr Helen Abud

We utilize differentiation of mouse embryonic stem cells to study the genes which control initial differentiation of intestinal lineage cells. This project involves embryonic stem (ES) cell culture, construct preparation, cell transfection, qPCR and immunohistochemistry.