The role of MicroRNA142 in Immunoregulation and Transplantation
Lead Research Organisation:
King's College London
Department Name: Immunology Infection and Inflam Diseases
Abstract
Kidney failure is a serious condition that affects more than 40,000 people in the UK. The safest and most effective treatment is a kidney transplant. However, when a patient receives a transplant, their immune system recognises it as foreign and tries to destroy it (this is called rejection). In order to prevent this, patients must take life-long medication, which can have side-effects and does not always prevent rejection.
There are patients who, without medication, seem to tolerate a transplanted kidney without rejection. Why this happens, and more importantly, how we can create this situation in all transplant patients (and therefore avoid having to use medication) is not yet fully understood.
This project aims to increase our understanding of the body‘s response to a transplant, and particularly how the immune system might be encouraged to tolerate it. To do this we will study samples from patients, healthy volunteers and laboratory mice. We also hope to identify a simple blood test that can predict whether the body‘s immune system is accepting or rejecting the transplant, which would help us to keep the transplant, and therefore the patient, healthy for as long as possible.
There are patients who, without medication, seem to tolerate a transplanted kidney without rejection. Why this happens, and more importantly, how we can create this situation in all transplant patients (and therefore avoid having to use medication) is not yet fully understood.
This project aims to increase our understanding of the body‘s response to a transplant, and particularly how the immune system might be encouraged to tolerate it. To do this we will study samples from patients, healthy volunteers and laboratory mice. We also hope to identify a simple blood test that can predict whether the body‘s immune system is accepting or rejecting the transplant, which would help us to keep the transplant, and therefore the patient, healthy for as long as possible.
Technical Summary
Background
MicroRNA (miRNA) are a class of short, non-coding RNA which regulate post-transcriptional gene expression and play a pivotal role in innate and adaptive immune responses.
Our laboratory focuses on the regulatory gene networks involved in CD4+ T cell differentiation and function. We have recently shown that the master regulatory T cell transcription factors T-bet and GATA3 bind to the promoter of microRNA (miR)142. In order to determine the function of miR142 in T cell lineage determination we have created novel constitutive and conditional knockout mice for this locus. These mice are viable and display a profound defect in their regulatory T cell (Treg) compartment.
A major goal in transplantation is the induction of tolerance; indefinite allograft survival without the need for life-long immunosuppression. Tregs are critical mediators of tolerance and express the transcription factor FoxP3. Co-expression of T-bet or GATA3 is important for Treg function in specific immune responses. However, the molecular mechanisms that regulate Treg function and stability are, to a large extent, unknown.
Aims and Objectives
The aim of the project will be to test the hypothesis that miR142 is important for Treg function by demonstrating that its altered expression has significant effects on Tregs and results in an immunological phenotype that affects outcomes in transplantation.
Design and Methodology
1. In vitro experiments will involve suppression assays on miR142 global and conditional (FoxP3) knock-out mice, testing the hypothesis that these mice have reduced Treg function. Parallel in vitro experiments will investigate the effects of miR142 over-expression in human cells.
2. In vivo experiments will utilise mouse models of transplantation to test the hypothesis that miR142 is implicated in allograft rejection, by comparing graft survival in wild type and knockout mice (constitutive and conditional).
3. Finally, the utility of miR142 as a biomarker of renal allograft status will be tested in human renal transplant recipients by looking at miR142 expression in peripheral blood before, during and after episodes of rejection.
Scientific and Medical Opportunities
This project will provide insight into the molecular mechanisms by which the immune system responds to allogenic stimuli. On a translational level, it could contribute to the development of a novel biomarker for the prediction of immunological tolerance. Indeed, there is emerging evidence that miR142 expression in human renal allograft biopsies predicts acute rejection. Furthermore, microRNAs are a potential target for therapeutic modulation with modified antisense oligonucleotides, furthering the search for novel specific immunosuppressants.
MicroRNA (miRNA) are a class of short, non-coding RNA which regulate post-transcriptional gene expression and play a pivotal role in innate and adaptive immune responses.
Our laboratory focuses on the regulatory gene networks involved in CD4+ T cell differentiation and function. We have recently shown that the master regulatory T cell transcription factors T-bet and GATA3 bind to the promoter of microRNA (miR)142. In order to determine the function of miR142 in T cell lineage determination we have created novel constitutive and conditional knockout mice for this locus. These mice are viable and display a profound defect in their regulatory T cell (Treg) compartment.
A major goal in transplantation is the induction of tolerance; indefinite allograft survival without the need for life-long immunosuppression. Tregs are critical mediators of tolerance and express the transcription factor FoxP3. Co-expression of T-bet or GATA3 is important for Treg function in specific immune responses. However, the molecular mechanisms that regulate Treg function and stability are, to a large extent, unknown.
Aims and Objectives
The aim of the project will be to test the hypothesis that miR142 is important for Treg function by demonstrating that its altered expression has significant effects on Tregs and results in an immunological phenotype that affects outcomes in transplantation.
Design and Methodology
1. In vitro experiments will involve suppression assays on miR142 global and conditional (FoxP3) knock-out mice, testing the hypothesis that these mice have reduced Treg function. Parallel in vitro experiments will investigate the effects of miR142 over-expression in human cells.
2. In vivo experiments will utilise mouse models of transplantation to test the hypothesis that miR142 is implicated in allograft rejection, by comparing graft survival in wild type and knockout mice (constitutive and conditional).
3. Finally, the utility of miR142 as a biomarker of renal allograft status will be tested in human renal transplant recipients by looking at miR142 expression in peripheral blood before, during and after episodes of rejection.
Scientific and Medical Opportunities
This project will provide insight into the molecular mechanisms by which the immune system responds to allogenic stimuli. On a translational level, it could contribute to the development of a novel biomarker for the prediction of immunological tolerance. Indeed, there is emerging evidence that miR142 expression in human renal allograft biopsies predicts acute rejection. Furthermore, microRNAs are a potential target for therapeutic modulation with modified antisense oligonucleotides, furthering the search for novel specific immunosuppressants.