CVS Barratt

Open to UK applicants only

Supervisors

• 1st:  Jonathan Barratt (jb81@le.ac.uk)
• 2nd: Haresh Selvaskandan (hs328@le.ac.uk)
• 3rd: Roisin Thomas (rct21@le.ac.uk)

Project Title: Interstitial responses in glomerular diseases

Project Description:

Glomerular diseases are a leading cause of kidney failure worldwide.1 IgA nephropathy (IgAN), IgA vasculitis (IgAV) and lupus nephritis (LN) are glomerular diseases that confer a high lifetime risk of progression to kidney failure, and predominantly affect young adults.2 Even with the recent approval of drugs that modulate glomerular haemodynamics or inflammation, most patients still progress to kidney failure.3,4 This confers an increased lifetime risk of morbidity and mortality.5 

Interstitial inflammation and fibrosis are strong predictors of progression to kidney failure, however the mechanisms driving these processes remain poorly defined. It is unclear if these mechanisms are common across immune complex mediated glomerular diseases such as IgAN, IgAV and LN, or if they are disease-specific. The pathways governing interstitial inflammation and fibrosis across these conditions need to be better defined, to allow the identification of targets for treatment which may meaningfully attenuate the risk of progression to kidney failure. 

This project will aim to define pathways mediating interstitial inflammation and fibrosis that are both common and different between three archetypal immune complex mediated glomerular diseases: IgAN, IgAV and LN, using pre-transfusion kidney transplant samples as healthy controls. 

To achieve this, the doctoral candidate will use a combination of approaches. Formalin Fixed Paraffin Embedded tissue blocks of kidney tissue will be retrieved and sectioned on to glass slides. The ethical approval for this is already in place. Tissue sections will then be stained for infiltrating immune cells (including macrophages, mast cells, T-cells and B-cells) with immunofluorescent markers, and will then be subject to digital spatial transcriptomics using the GeoMx platform (which our laboratory has experience with and access to). This will allow infiltrating immune cells and the interstitium immediately surrounding them to be transcriptomically profiled with next generation sequencing. 

The data generated will be analysed using bioinformatic pipelines optimised by our laboratory, and pathway analysis will be performed to identify key receptor-ligand pairs between infiltrating cells and surrounding tissue that maybe mediating inflammation and fibrosis. Pathways that are common to the three diseases as well as unique to them will be identified. In-silica analysis, in collaboration with the EMBL institute, will be used to identify pathways most amenable to modulation by therapies that already exist. 

The functional relevance of modulating these pathways will then be demonstrated in vitro using tissue culture of proximal tubular epithelial cells and collecting duct cells, which our laboratory has experience growing. 

Brief plan of research:

Year 1

• Identify 20 matched kidney biopsies of IgAN, IgAV, LN and healthy controls each
• Perform digital spatial profiling using the Nanostring GeoMx platform on the identified samples
• Bioinformatic analyses of transcriptomic data generated through digital spatial profiling to identify receptor-ligand pairs which maybe driving inflammation and fibrosis, common across all conditions as well as unique to each condition 

Year 2

• In silica analyses to identify pathways most amenable to modulation with existing therapies, in conjunction with the EMBL institute. 
• Begin growing and maintaining proximal tubular epithelial cell and collecting duct cell lines 
• Functionally validate pathways that may be amenable to modulation using these cell lines, using siRNAs and expression vectors, qPCR, and western blotting. 

Year 3

• Completion of cell culture experiments 
• Thesis write up. 

References: 

1. Gupta R, et al Epidemiology of end-stage kidney disease. Semin Vasc Surg. 2021 Mar;34(1):71-78. 
2. Wong K, et al. Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort. Lancet. 2024 Mar 30;403(10433):1279-1289. 
3. Gatto M et al. Effect of Sustained Clinical Remission on the Risk of Lupus Flares and Impaired Kidney Function in Patients With Lupus Nephritis. Kidney Int Rep. 2024 Jan 19;9(4):1047-1056.
4. Pitcher D, et al. Long-Term Outcomes in IgA Nephropathy. Clin J Am Soc Nephrol. 2023 Jun 1;18(6):727-738. 
5. Francis A et al. Chronic kidney disease and the global public health agenda: an international consensus. Nat Rev Nephrol. 2024 Jul;20(7):473-485.