Theme 1: Mechanisms of nephritogenic immune responses and renal injury

Supervisors:

  Professor Stephen Holdsworth
  T: 9594 5525
  E: Stephen.Holdsworth@med.monash.edu.au

  A/Professor Richard Kitching
  T: 9594 5520
  E: Richard.Kitching@med.monash.edu.au

Description:

Glomerulonephritis (GN) is the most common cause of end stage renal failure in Australia and world-wide. The overall aim of this theme is to further our understanding of key events in the generation of nephritogenic immune responses, autoimmunity as it pertains to the kidney and effector responses in the kidney, so that potential therapeutic targets can be identified. Research in our laboratories covers a range of key questions as to why the kidney can be a target of immune attack. It uses a variety of techniques that involve models of disease, transgenic and knock out mice, molecular biology, cell culture, analysis of immunological endpoints, and histological and functional readouts. A variety of projects are available in

1         Role of Mast Cells in Kidney Disease

Supervisor Prof S Holdsworth

Recent research confirms that mast cells have broad capacities in immunity beyond their traditional roles in allergy.  They are found in close proximity to blood vessels in many organs where they are strategically placed to orchestrate or regulate leukocyte driven host defence and injury.Recent studies show they accumulate in the kidney in most major human kidney diseases including transplant rejection, inflammation, diabetic nephropathy and ischaemia reperfusion injury.

Their role of mast cells in these forms of injury is as yet undefined.  We have established a colony of mast cell deficient mice.  The availability of these mice will enable us to formally asses the role of these mast cells by comparing the development of disease in mast cell intact and deficient mice.  The project will allow a student to define the role of mast cells in a relevant model of one of these important human diseases.

2         The role of Toll like receptor 9 (TRL9) in neutrophil mediated renal injury.

Supervisor Prof S Holdsworth

Toll Like receptors (TLRs) are now recognised to be major detectors of microbial infection.  Nine different TLRs have been defined. They recognise conserved microbial motifs that distinguish them from the host and activate leukocytes to enhance innate immune defence.  However TLRs also play an injurious role in autoimmune tissue injury.

Antibodies binding to glomeruli attract neutrophils to induce severe injury.  We have recently shown that a major TLR9 ligand (CpG) significantly enhances this injury (but not in TLR9 -/- mice).  Many forms of human glomerulonephritis are induced by autoantibodies.  The two most important are anti glomerular basement membrane (GBM) antibodies and anti neutrophil cytoplasmic antibodies (ANCA).  These antibodies both induce neutrophil mediated injury in mice but by different mechanisms.  Anti GBM antibody binds to the glomerular capillary basement membranes but ANCA binds to neutrophils themselves. 

This project will define the mechanisms of TLR9 (CpG) induced neutrophil activation and recruitment by both autoantibodies including the roles of chemokines, complement, intrinsic renal cells and key intracellular signalling molecules.

3         Induction and Regulation of immune responses that affect the kidney.

Supervisor Prof S. Holdsworth

These studies will particularly focus on the roles of newly described T cell cytokines and costimulatory molecules that are potentially important in immune responses that lead to renal injury.\

4 Studying effector Th1 and Th17 responses in glomerulonephritis using a novel TcR transgenic cell transfer model

Supervisors: A/Prof Richard Kitching, Dr Oliver Steinmetz

Richard.kitching@med.monash.edu.au

Cell mediated immunity is important in severe rapidly progressive forms of glomerulonephritis. We have recently established a new models of glomerulonephritis where a model antigen, ovalbumin can be planted in the glomerulus and antigen-specific T cells polarized to a Th1 or Th17 transferred in to cause pure Th12 or Th17 cell mediated injury. Further studies currently planned and offered as honours projects include:

a)    Determining whether effector injury can be enhanced in the same manner in Th1 and Th17 mediated injury be TLR2, TL4 or TLR9 agonists?

b)    Do CD4+ and CD8+ cells play synergistic roles in cell mediated injury?

c)    Do Th1 and Th17 synergise in the development of glomerular injury?

d)    Can co-transfer of GFP+ Foxp3 Tregs ameliorate injury?

Techniques involved in this project include: culture of TcR Tg T cells with antigen, cytokines and antibodies; in vivo animal work; molecular biology; flow cytometry, histology, immunohistochemistry and immunofluorescence and ELISA.

5 Can inhibiting IL-12p40 prevent or treat experimental crescentic glomerulonephritis?

Supervisor: A/Prof Richard Kitching (Department of Medicine)

Richard.kitching@med.monash.edu.au

IL-12p40 forms part of both IL-12 (important for Th1 responses) and IL-23 (important for Th17 responses). Targeting IL-12p40 is an approach to treating proliferative and crescentic forms of GN that could be successful in both Th1 and in Th17 mediated RPGN. Agents targeting IL-12p40 been effective in experimental non-renal inflammatory disease and are in Phase II clinical trials. This project will determine the capacity of apilimod (a small molecule IL-12p40 inhibitor) to inhibit experimental crescentic glomerulonephritis. An initial study will commence treatment at the induction of disease and continue for 21 days, later studies will commence at days 7 or day 10 and continue until day 21 or day 35.

Techniques involved in this project include in vivo animal work; molecular biology; flow cytometry, histology, immunohistochemistry and immunofluorescence and ELISA.

6 Induction of nephritogenic autoimmune anti-myeloperoxidase responses using a Staphylococcus aureus derived peptide

Supervisors: A/Prof. Richard Kitching, Dr. Joshua Ooi

Richard.kitching@med.monash.edu.au; Joshua.ooi@med.monash.edu.au

Experimental data suggests that the loss of tolerance to myeloperoxidase (MPO), which is found prominently in neutrophils, leads to glomerulonephritis; known as MPO-ANCA associated glomerulonephritis. It has also been reported that in some patients a Staphylococcus aureus infection precedes the loss of tolerance to myeloperoxidase. This project will test the hypothesis that molecular mimicry by a Staphylococcus aureus derived peptide can lead to the loss of tolerance to myeloperoxidase and lead to MPO-ANCA associated glomerulonephritis.

Techniques involved in this project include in vivo animal work; lymphocyte proliferation assays, histology, immunohistochemistry and immunofluorescence; and ELISA and ELISPOT

7 The role of renal dendritic cells in a mouse model of kidney transplantation

Supervisors: A/Prof. Richard Kitching, Dr. Sarah Snelgrove

Richard.kitching@med.monash.edu.au; Sarah.snelgrove@med.monash.edu.au

In Australia, approximately two-thirds of organ transplants are kidney transplants. When this procedure is performed, there is a period of time during which there is no blood supply to the kidney (termed ischaemia), followed by restoration of blood flow (reperfusion). Ischaemia/reperfusion injury (IRI) is a major cause of kidney dysfunction and has a crucial impact on graft survival. Renal IRI induces an influx of leukocytes including dendritic cells (DCs) to the kidney. DCs are antigen presenting cells which initiate tolerogenic and immunogenic immune responses. Renal DCs have not been extensively studied, and the importance of these cells in the kidney is only now being recognised. We are using a mouse model of IRI to mimic what happens during a kidney transplant operation. The aim of this project will be to investigate the role of renal DCs following IRI and to characterise the phenotype, recruitment and function of these cells in the kidney. Studies currently planned and offered as honours projects include

a)    the role of renal DCs in IRI under immunosuppression

b)    the effect of IRI on the antigen presenting capacity of renal DCS

c)    Which type of DC adheres best in the kidney

This project will utilize whole animal in vivo work, tissue culture, flow cytometry, cell transfer, working with TcR transgenic T cells and in vivo imaging by multi-photon microscopy.