Exploring HLA-B*27-targeted RNAi therapy for Ankylosing Spondylitis
- Project No: #OxKEN-2021/12
- Intake: OxKEN
Ankylosing Spondylitis (AS) is a common form of arthritis with an unusually strong genetic association with HLA-B*27 (90% in AS vs 5% in healthy control). Theories proposed to explain HLA-B27’s role in AS pathogenesis include 1) presentation of arthritogenic peptide(s), 2) intracellular and cell surface expression of HLA-B27 free heavy chains (FHC). HLA-B27 FHCs enhance interleukin (IL)-17 production in AS through binding to KIR3DL2 expressed on T cells 1. Both HLA-B*27 peptide presentation and FHC cell surface expression can be modulated through the suppression of endoplasmic reticulum aminopeptidase 1 (ERAP1, another genetic risk in AS) 2 3. However, development of drugs targeting HLA-B*27 FHC or ERAP1 have proven challenging due to technical reasons or safety concerns. Thus, despite the genetic and biological evidence highlighting the key role of HLA-B*27 in AS, drugs targeting HLA-B*27 have not been developed.
RNA interference (RNAi) was discovered twenty years ago but its development for clinical application has been halted for a long time due to stability and delivery issues. These issues have been solved recently, leading to the development of the first successful RNAi drug approved for hereditary ATTR amyloidosis in 2018. Earlier this year, RNAi targeting PCSK9, a genetic risk for coronary artery disease, was approved as the low-density lipoprotein cholesterol (LDL-C) lowering treatment. PCSK9 RNAi shows an afficacy similar to that of PCSK9 antibodies but is cheaper and only requires twice-yearly dosing, thus saving the healthcare cost.
This project aims to explore the translational value of HLA-B*27 RNAi in AS. Patients with AS have enhanced lymphocyte IL-17 responses and monocyte TNF-alpha response 4 5, with antibodies blocking IL-17 and TNF-alpha currently used for AS treatment. In this project you will firstly investigate the impact of HLA-B*27 knockdown/knockout on the IL-17 and TNF-alpha response in lymphocytes and monocytes from HLA-B*27+ AS patients. You will stimulate patient cells, including whole blood, synovial fluid and T cells and monocytes isolated from these sources, with T cell activators including cytokines, pathogen-derivatives and whole bacteria under different conditions. The role of HLA B27 and its mechanism of action will then be studied especially for lymphocyte IL-17 production, which is largely unknown.
Ankylosing Spondylitis, HLA-B*27, RNAi therapy, TNF-alpha, IL-17
You will receive broad training in immunology and molecular biology including: 1) human primary T cell and monocyte culture, 2) designing and performing inflammation-relevant cellular assays using primary immune cells (techniques including ELISA, flowcytometry, qPCR and western blot), 3) gene RNAi knockdown and CRISPR-knockout in primary T-cells and monocytes (techniques including standard molecular biology techniques, lentivirus production for gene knockdown and overexpression), 4) bulk and/or single cell RNA-seq for mechanistic study, 5) designing cellular assays to model inflammation-driven disease for translational investigation.
A core curriculum of lectures will be taken in the first term to provide a solid foundation in a broad range of subjects including musculoskeletal biology, inflammation, epigenetics, translational immunology, data analysis and the microbiome. Students will also be required to attend regular seminars within the Department and those relevant in the wider University. Students will be expected to present data regularly in Departmental seminars, lab meeting within Chen and Bowness groups and to attend external conferences to present their research globally, with limited financial support from the Department.
Students will have access to various courses run by the Medical Sciences Division Skills Training Team and other Departments. All students are required to attend a 2-day Statistical and Experimental Design course at NDORMS and run by the IT department (information will be provided once accepted to the programme).
1. Bowness P, Ridley A, Shaw J, et al. Th17 cells expressing KIR3DL2+ and responsive to HLA-B27 homodimers are increased in ankylosing spondylitis. J Immunol 2011;186(4):2672-80. doi: 10.4049/jimmunol.1002653 [published Online First: 2011/01/21]
2. Chen L, Fischer R, Peng Y, et al. Critical role of endoplasmic reticulum aminopeptidase 1 in determining the length and sequence of peptides bound and presented by HLA-B27. Arthritis Rheumatol 2014;66(2):284-94. doi: 10.1002/art.38249 [published Online First: 2014/02/08]
3. Chen L, Ridley A, Hammitzsch A, et al. Silencing or inhibition of endoplasmic reticulum aminopeptidase 1 (ERAP1) suppresses free heavy chain expression and Th17 responses in ankylosing spondylitis. Ann Rheum Dis 2016;75(5):916-23. doi: 10.1136/annrheumdis-2014-206996 [published Online First: 2015/07/02]
4. Al-Mossawi MH, Chen L, Fang H, et al. Unique transcriptome signatures and GM-CSF expression in lymphocytes from patients with spondyloarthritis. Nat Commun 2017;8(1):1510. doi: 10.1038/s41467-017-01771-2 [published Online First: 2017/11/17]
5. Shi H, Chen L, Ridley A, et al. GM-CSF Primes Proinflammatory Monocyte Responses in Ankylosing Spondylitis. Front Immunol 2020;11:1520. doi: 10.3389/fimmu.2020.01520 [published Online First: 2020/08/09]