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Start date: June 2025
Duration: 3 years
Background:
Discoid lupus erythematosus (DLE) is a chronic scarring dermatosis with a predilection for the head and neck. It is associated with a significant psychosocial burden with high rates of depression and social isolation reported amongst patients suffering from the disease. Current treatment options for DLE include topical agents, immunomodulatory agents or immunosuppressants, but current treatments lack efficacy and can be associated with side effects.
A hindrance to the development of targeted treatments for DLE is our incomplete understanding of disease pathogenesis. A defining pathological feature of DLE is keratinocyte apoptosis of the dermal-epidermal junction as well as aggregates of B and T cells in the peri-appendageal areas on the dermis. B cells are seen in high numbers in DLE lesions, although their phenotype and role in disease pathogenesis is not understood.
In order to phenotype cutaneous immune cells in DLE skin we designed a panel of metal tagged antibodies targeting key lineage markers and markers of activation and differentiation for T, B and myeloid cells. A preliminary analysis has demonstrated high expression of CD74 on myeloid and B cells in DLE lesions. CD74 is a receptor for macrophage migratory inhibitory factor (MIF) as well as acting as an MHC class II chaperone protein. MIF has multiple proinflammatory effects via stimulating inflammatory cytokine release, promoting leucocyte recruitment and tissue residence as well as acting as a survival factor. The role of MIF and CD74 in the pathogenesis of DLE is, however, not understood. In systemic lupus erythematosus (SLE) MIF levels correlate with disease activity and organ involvement. Furthermore, a phase 1b trial of the CD74 monoclonal antibody antagonist milatuzumab in patients with SLE demonstrated improvement in mucocutaneous lesion. However, the effects of MIF or CD74 antagonism on cutaneous lupus has not yet been specifically investigated.
This project will investigate the functional significance of CD74 in DLE and the effects of its antagonism.
Experimental aims:
Aim 1 : Analysis of an existing IMC dataset
This will involve analysis of an IMC dataset of 8 DLE skin biopsies and 8 health control donor (HCD) biopsies. Images will be normalised, and cell segmentation will be performed using established pipelines developed by the Bodenmiller laboratory. Cell classification will then be performed. Our laboratory has experience of using Random Forest Classification but there is scope to use other classification methods to for this dataset. The frequency and phenotype of immune cell subsets will then be compared between DLE and HCD and a neighbourhood analysis will then be performed to look at cell-cell interaction.
Aim 2 : Use of spatial transcriptomics to identify disease relevant pathways associated with high CD74 expression
This aim will utilise the cutting edge Visium HD spatial transcriptomics platform which allows sequencing of the entire transcriptome of a tissue section at single cell resolution. This enables tissue phenotyping at unparalleled depth and will compare the transcriptome of cells with high and low CD74 expression to identify differentially expressed genes. This will identify disease associated pathways such as inflammatory cytokine production, altered expression of chemokines, cell homing receptors and aberrant cell maturation such as extrafollicular B cell differentiation. Visium HD will also allow a neighbourhood analysis to be performed to identify whether CD74 as a chaperone molecule to MHC Class II is involved in antigen presentation and immune cell crosstalk.
Aim 3 : Investigating the effects of the CD74 antagonist milatuzumab on normal skin and DLE lesions
This aim will initially investigate the effects of intradermal administration of milatuzumab into healthy skin samples at different doses with in vivo culture at different time points. Flow cytometry and immunohistochemistry will be used to identify the effects on leucocyte migration and tissue viability. The effect of milatuzumab on DLE biopsies will then be investigated using this in vivo culture model. Flow cytometry will be used to identify changes in cellular composition. Immunohistochemistry and immunofluorescent microscopy will also be used to investigate changes in inflammatory cytokine and leucocyte adhesion molecule expression within the skin.
Importance: this project will phenotype immune cells in DLE with unparalleled depth. It will also investigate the functional significance of CD74 in DLE and could form the basis for future work to develop CD74 antagonists as a novel therapy for the disease.
Training and research environment
This project will combine bioinformatic training with wet lab work to develop the student’s skills in tissue culture, flow cytometry and immunohistochemistry.
St John’s Institute of Dermatology (School of Basic and Medical Biosciences, King’s College London) is an internationally renowned centre for the delivery of innovative clinical care for patients with skin diseases, cutting-edge education, training, and research. St John’s occupies 1,200 square metres of state-of-the-art laboratory space (Guy’s Hospital campus) and is fully integrated into the Faculty of Life Sciences & Medicine's School of Basic & Medical Biosciences. Kings College London is part of King’s Health Partners, one of the UK’s five Academic Health Sciences Centres, where world-class research, teaching and clinical practice are brought together for the benefit of patients.
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