Functional role of HLA-C in Psoriasis
Lead Research Organisation:
King's College London
Department Name: Medicine School Office
Abstract
We aim to study the role of a major psoriasis candidate gene. This will improve our understanding of the genetic and immunological basis of psoriasis, leading to better treatments and improved quality of life.
Psoriasis is a common lifelong inflammatory skin disorder affecting approximately 2% of the population worldwide. It causes significant morbidity and mortality and results in major economic burden with the global therapeutic cost estimated to be over $6.7 billion worldwide and the costs to NHS exceed £50 million per annum. Current existing therapies only relief symptoms but cannot cure disease, they also carry substantial side effects.
The precise cause of psoriasis is unknown but available evidence favours dysregulation of the immune system playing a major role. Our group has made significant contribution in resolving the genetic and immunological basis of psoriasis and we have narrowed down the potential psoriasis gene to a well defined region within the human genome. In this project, we will use different model systems which closely mimic the human skin environment, thereby enabling us to study the earliest events in psoriasis and to dissect the functional as well as potential therapeutic role of psoriasis relevant genes in psoriasis.
Psoriasis is a common lifelong inflammatory skin disorder affecting approximately 2% of the population worldwide. It causes significant morbidity and mortality and results in major economic burden with the global therapeutic cost estimated to be over $6.7 billion worldwide and the costs to NHS exceed £50 million per annum. Current existing therapies only relief symptoms but cannot cure disease, they also carry substantial side effects.
The precise cause of psoriasis is unknown but available evidence favours dysregulation of the immune system playing a major role. Our group has made significant contribution in resolving the genetic and immunological basis of psoriasis and we have narrowed down the potential psoriasis gene to a well defined region within the human genome. In this project, we will use different model systems which closely mimic the human skin environment, thereby enabling us to study the earliest events in psoriasis and to dissect the functional as well as potential therapeutic role of psoriasis relevant genes in psoriasis.
Technical Summary
Psoriasis is a genetically determined chronic inflammatory cutaneous disorder characterised by epidermal hyperplasia, dermal inflammation and epidermal infiltration by CD8 T cells. The precise disease aetiology is unknown but a better understanding of disease pathogenesis will be paramount for the development of new and improved therapies. Available evidence suggest that psoriasis is an immunologically mediated disease. The most significant genetic susceptibility locus in psoriasis PSORS1 contains a strong candidate gene HLA-C which is a powerful immunological regulator. The current proposal hypothesizes that in particular one of its alleles HLA-Cw6 shows a dysregulated expression in psoriasis providing the basis for aberrant lymphoid effector function activation and immunopathology in psoriasis. We therefore aim to first investigate the expression of HLA-C and more specifically HLA-Cw6 (mRNA and protein) in tissue samples derived from psoriatic plaques (PP), uninvolved psoriatic skin (PN), inflammatory control skin (e.g. atopic dermatitis) and healthy control skin (NN), as well as in peripheral blood from psoriasis patients, inflammatory controls and healthy controls. Qualitative and quantitative expression patterns will by analysed at the transcript level by RT-PCR, respectively, and at the protein level by immunohistochemistry, western blotting and flow cytometry.
We aim to further assess the functional relevance of HLA-Cw6 extression in in vitro models and to define and modulate the temporal and spatial expression of HLA-Cw6 in clinically relevant in vivo models. To obtain an in vitro model system of HLA-C function we will use an approach which ensures the expression of different HLA-C alleles from the identical chromosomal position resulting in comparative data on the intrinsic post-transcriptional and translational expression levels and turnover of each allele. In co-culture experiments, cell lines or primary human cells transfected with HLA-alleles will be assessed for their capacity to modulate the response of freshly isolated human effector lymphocytes or cell lines.
To complement these studies, the regulation of HLA-C expression in vivo will be studied using human uninvolved skin that is transplanted from psoriatic patients to compound immunodeficient mice and that progresses to florid pathology in situ over several weeks (AGR psoriasis mouse model). Using lentiviral mediated in vivo gene delivery overexpression as well as downregulation of HLA-Cw6 in the upper layers of the xenograft will be assessed for their impact on developing psoriasis lesions.
In summary, the proposed studies will lead to a better insight into disease pathogenesis at the interface between genetics and immunology, and provide the basis for potentially novel treatment approaches.
We aim to further assess the functional relevance of HLA-Cw6 extression in in vitro models and to define and modulate the temporal and spatial expression of HLA-Cw6 in clinically relevant in vivo models. To obtain an in vitro model system of HLA-C function we will use an approach which ensures the expression of different HLA-C alleles from the identical chromosomal position resulting in comparative data on the intrinsic post-transcriptional and translational expression levels and turnover of each allele. In co-culture experiments, cell lines or primary human cells transfected with HLA-alleles will be assessed for their capacity to modulate the response of freshly isolated human effector lymphocytes or cell lines.
To complement these studies, the regulation of HLA-C expression in vivo will be studied using human uninvolved skin that is transplanted from psoriatic patients to compound immunodeficient mice and that progresses to florid pathology in situ over several weeks (AGR psoriasis mouse model). Using lentiviral mediated in vivo gene delivery overexpression as well as downregulation of HLA-Cw6 in the upper layers of the xenograft will be assessed for their impact on developing psoriasis lesions.
In summary, the proposed studies will lead to a better insight into disease pathogenesis at the interface between genetics and immunology, and provide the basis for potentially novel treatment approaches.