Targeting GSK-3 in antigen-specific immunotherapy

In 1911, Noon and Freeman published their account of the treatment of a hay fever sufferer with pollen extract. This was one of the first documented descriptions of specific immunotherapy (SIT) in which the agent causing the allergic condition was used to 'desensitise' the patient. While the value of SIT has been widely accepted, the approach still carries the risk of severe side effects including anaphylactic shock. The investigation of SIT for treatment of autoimmune diseases has lagged behind that of SIT in allergy and has also been hampered by aberrant events. For example, administration of a brain protein exacerbated a disease resembling MS in primates. Similarly, administration of an artificial islet antigen, via the lung or gut, induced T lymphocytes that exacerbated autoimmune diabetes in an animal model. The complications associated with intact antigen have led opinion leaders in the field to recommend the use of fragments of proteins called 'synthetic peptides' for SIT.
Our laboratory studies the design and mode of action of peptides that are able to suppress immune responses. Effective induction of suppression depends on the solubility of the peptide. Previously we had shown that some peptides failed to mediate SIT even when administered in a highly soluble form. This proved to be because the peptides could bind to their receptor, an immune molecule called MHC, to produce the wrong shape or conformation. Peptides can be designed, however, to fit the MHC appropriately and these then induce tolerance to the native protein. Effective SIT with peptides leads to the induction of a subset of lymphocytes, known as CD4 T-cells, and they secrete a protein called IL-10. IL-10 is a hormone-like substance, known as a cytokine, that suppresses activation of neighbouring T cells in the body via a negative feedback loop mechanism. It was recently shown that peptide SIT in allergic asthma also generates IL-10-dependent suppression thus revealing a similar role for IL-10 in SIT for both allergy and autoimmune disease.
The overall aim of this current proposal is to improve the efficacy of peptide-induced SIT by enhancing the conversion of lymphocytes capable of causing disease into IL-10 secreting disease suppressor cells. Recently we showed that the addition of drugs that block the activity of the enzyme GSK-3 to cultures of lymphocytes in vitro greatly enhanced their production of IL-10. The specific aims of this project are, therefore, to:
i. identify the most suitable GSK-3 inhibitor from a panel previously characterised by GSK
ii. investigate the ability of GSK-3 inhibitors to enhance the in vivo generation of IL-10 secreting suppressor cells in conjunction with SIT in a relevant animal model of autoimmune disease
iii. confirm the activity of the selected inhibitor/s on human lymphocytes
iv. assess the stability of the IL-10 phenotype in both mouse and human cells
There are no patents relating to these compounds and, as a result, no 'freedom to operate' issues associated with them. We propose a novel application for these compounds, as adjunct treatments, in conjunction with SIT, for immunotherapy of autoimmune diseases and allergies. We have conducted patent searches relating to this application of the drugs and have not found prior art.
The enhancement of IL-10 production during SIT will greatly improve the efficacy of this therapeutic approach. As such, the use of GSK-3 inhibitors as adjunct therapy will be applicable to any allergic condition currently treated by SIT or equally to any autoimmune condition for which the target antigens are known. The improvement of SIT provided by co-administration of GSK-3 inhibitors will allow health care providers to move away from the use of non-specific therapies for allergic and autoimmune diseases since these are often ineffective and can cause severe side effects. This improvement will be of considerable benefit to both patients and the health care system.

Current therapies for allergies and autoimmune diseases treat the symptoms rather than the cause of the disease. The exception to this is antigen-specific immunotherapy (SIT) that aims to reinstate tolerance to the protein causing the disease. This approach has been applied in the field of allergy for over 100 years; however, the SIT approach has not yet transferred successfully from allergy to autoimmunity. Furthermore, SIT using intact allergens still runs the risk of inducing anaphylactic shock. The ultimate aim of this DPFS project is to develop an approach that enhances the efficacy and hence permits commercial development of SIT. Our laboratory has made two significant advances: first, we demonstrated that intact antigens can be replaced with synthetic peptides for effective SIT and second, we recently identified an enzyme whose inhibition greatly enhances the SIT effect, in vitro. As yet, the enzyme inhibitors tested have been poorly soluble and have not been tested in vivo for SIT. We will investigate a new enzyme inhibitor that is highly soluble and effective against the enzyme in vivo. This will be tested first against the enzyme in mouse and human lymphocytes in vitro. If effective, we will test how inhibiting the enzyme enhances SIT using animal models of autoimmune disease. We propose that transient enzyme inhibition in lymphocytes will enhance SIT thereby avoiding potential adverse effects of long-term drug administration. We believe that the combined safety of peptides rather than intact protein for SIT, along with the enhanced efficacy achievable with our enzyme inhibitor, will promote SIT to the forefront of preferred treatments for allergic and autoimmune diseases. The immediate goal of this project is to demonstrate the enhancement of SIT by targeting this particular enzyme, and to provide sufficient in vitro and in vivo evidence to interest industry in further development of this approach through collaboration.

The ultimate aim of the work being undertaken in the Wraith laboratory is to improve the health of patients suffering from allergic and autoimmune diseases by developing improved treatments for their diseases. This is especially true for this particular project which is designed to enhance the efficacy of antigen-specific immunotherapy (SIT) for treatment of these diseases. Below this ultimate aim, however, are a range of beneficiaries that I will consider in turn.
The research undertaken will impact on the individual employed on this project. Dr Bronwen Burton will gain a further three years of training in cellular immunology. In addition, however, this project will introduce her to the concept of drug discovery and development. Under the MTA and CDA agreements between GSK and University of Bristol, we will discuss our findings with colleagues at GSK and this will introduce Bronwen to the academia-industrial interface.
The scientific discoveries arising from this project will provide further understanding of the role of GSK-3 in regulating immune function. This will have a major impact on our understanding of lymphocyte function, will lead to the publication of high impact papers in scientific journals and the dissemination of this knowledge among the academic community and beyond. Furthermore, the application of these findings to the treatment of autoimmune and allergic diseases may be sufficiently powerful to allow establishment of a new spin-out company leading to substantial R&D investment into the region. Prof Wraith has always striven to realise the full commercial potential of his work. For example, in the 1980s, while working at the MRC National Institute for Medical Research, he patented a novel influenza vaccine designed to stimulate heterotypic immunity against the virus; in the 1990s, while working at Stanford University, he patented the use of altered peptide ligands for treatment of autoimmune diseases and over the past 10 years he has patented methods for the design of therapeutic peptides and further patents on specific combinations of peptides for immunotherapy. The commercialisation and exploitation of his knowledge, relating to therapeutic peptides, led to the establishment of the University of Bristol spin out company Apitope. It is clear that he will take every opportunity to exploit the discoveries from this project, preferably by the licensing of any technology to a pharmaceutical company. It is likely that UK-based companies including Apitope, Circassia and GSK would benefit from licensing the scientific advances that will be made during this project, although GSK is not currently pursuing the SIT approach. This work will enhance the research capacity in the field of immunology ultimately allowing either a new spin-out or other UK companies to build competitiveness in the pharmaceutical market thereby leading to wealth creation and improved prosperity both regionally and nationally. The Apitope story is a good example: this company has benefited from substantial R&D investment from abroad leading to the creation of 20 full and part-time jobs in the south-west region.
As stated above, the primary goal of this project and the work of the Wraith laboratory in general, is to improve the quality of life and health of the millions of people in the UK and worldwide who suffer from allergic and autoimmune diseases. Successful completion of the steps leading to this goal will be communicated to the general public and, in this way, will provide convincing evidence to them of how investment in science can lead to substantial improvements in health.