MOLECULAR IMMUNOLOGY

• Staff
  • Laboratory Head
  • Research Staff
  • Students
• Goals
• Research Projects
  1. Molecular identification of Regulatory T cells
  2. Treg defects in autoimmune disease
  3. Lentiviral vectors for gene ddiscovery, gene over expression and gene ablation
  4. A novel role for FOXP3 as a tumour suppressor in Breast Cancer

STAFF

Laboratory Head

Associate Prof. Simon Barry

Ph: 08 8161 6562

Email: simon.barry@adelaide.edu.au

Research Staff

Students

GOALS

To improve our understanding of regulatory T cell function through studies of gene expression, transcription factors and surface molecules and to develop regulatory T cells for cell therapy.

RESEARCH PROJECTS

1. Molecular identification of Regulatory T cells

The recent identification of regulatory T cells (Tregs) as a key mediator of central and peripheral tolerance has led to an increase in our understanding of the cellular mechanisms by which we maintain immune homeostasis. The transcription factor FoxP3 is essential for formation and function of a subset of T cells that have regulatory capacity. There is however, very little known about the molecular basis of this process. This project has identified for the first time the genes directly regulated by human FoxP3 and we are now determining their role in the regulatory phenotype. We have used a number of direct and indirect molecular approaches such as Chromatin Immunoprecipitation and microarray analysis to profile genes regulated by FoxP3, and we will validate their role in regulatory function by direct assays and by over expression or gene ablation studies. The candidate genes identified in this approach may lead to therapeutic approaches for intervention in the function of regulatory cells, and will also have application for diagnostic analysis of regulatory cell function. We have also identified a novel Treg biomarker which we are co developing with the CRC for Biomarker Translation.

2. Treg defects in autoimmune disease

The clinical implications of regulatory T cell defects are apparent in many autoimmune diseases including Inflammatory Bowel Disease (IBD) and Crohns disease. We have performed a pilot study to analyse the proportion of Treg vs a new effector population, Th17 cells, which are implicated in disease pathology. We observed that relative to healthy controls there is a decrease in numbers of Treg in IBD and Crohns disease, and an elevation of the number of Th17 cells in the same patients. When expressed as a ratio we observed that there is near 1:1 Treg:T effecter in healthy peripheral blood samples, but that this is significantly reduced in these autoimmune disease patients. We now aim to determine if this blood measure is predictive or if it can be used to monitor therapy efficacy in IBD and other autoimmune disease.

Analysis of the Treg:Th17 ratio in control and IBD or Crohns patient groups showing a reduction in the ratio of these cells in both autoimmune disease groups

3. Lentiviral vectors for gene discovery, gene over expression and gene ablation

Primary cells are refractory to standard transfection protocols and, since they are often of low mitotic index, they are only infected at low efficiency by murine retroviruses (RV), which require cell division for integration. The recent development of HIV1 based lentivectors (LV) provides an attractive option for gene delivery into T cell and stem cell populations, as these viruses carry the necessary cis elements to facilitate nuclear transport and integration in the absence of cell division. We have developed a suite of lentiviral vectors for stable gene delivery into primary cells for gene therapy, gene discovery and gene ablation using RNA interference. As part of the Australian Retroviral expression cloning consortium (ARVEC) we are building the capacity to undertake large scale automated lentiviral expression cloning in a 96 well format, with the intention of screening all available full length clones in the human genome collection. This facility will allow function based gene identification in any cell that can be cultured in plates.

Lentiviral delivery of shRNAi showing ablation of FoxP3 expression that is inducible with doxycycline and is reversible

4. A novel role for FOXP3 as a tumour suppressor in Breast Cancer

FoxP3 was very recently implicated as a novel breast cancer tumour suppressor, as mice lacking functional Foxp3 develop breast cancer (BC) at significantly elevated levels. We have identified a number of candidate genes including SATB1 as direct targets of Foxp3 and now show that loss of Foxp3 results in elevated levels of SATB1. We are defining the molecular regulation by FOXP3 and investigating the role of micro RNAs (miRs) in this process. This may provide new therapies for intervention in BC by ensuring that Foxp3 expression is maintained.