URINARY EXTRACELLULAR VESICLES AS PROGNOSTIC BIOMARKERS OF TUBULAR FERROPTOSIS IN ACUTE KIDNEY INJURY PROGRESSION
Dr Andrew Kassianos1,2, Dr Chang Seong Kim1,2,3,4, Mr Benjamin Adams1,2,5, Dr Monica Suet Ying Ng1,2,5, Associate Professor Helen Healy1,2,5, Dr Andrew Kassianos1,2,5
1Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Australia, 2Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Australia, 3Department of Internal Medicine, Chonnam National University Hospital, Gwangju, Republic of Korea, 4Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea, 5Faculty of Medicine, University of Queensland, Brisbane, Australia
Aim: To establish urinary extracellular vesicles (EV) as prognostic indicators of acute kidney injury (AKI) progression.
Background: Approximately 40% of AKI survivors progress to chronic kidney disease (CKD), significantly increasing their risk for premature death. We have reported that AKI progression is driven by tubular ferroptosis propagated along the apical lumen/urinary space by specialised EV (ie exosomes). Here, we investigate the prognostic utility of urinary EV isolated from AKI patients.
Methods: Urine samples (50-100ml) were obtained from people with AKI at presentation. Individuals were stratified into two groups based on follow-up kidney function at ≥3 months post-AKI episode: ‘AKI recovery’ (eGFR≥60ml/min/1.73m²) or ‘AKI progressors’ to CKD (eGFR<60 ml/min/1.73m²). Control urine was obtained from age/sex-matched healthy donors. Urinary EV were isolated by size exclusion chromatography (qEV columns) and analysed for size/concentration (qNano), miRNA cargo (sequencing) and in functional co-culture assays with healthy human primary proximal tubular epithelial cells (PTEC) (2D) and tubular epithelial organoids (tubuloids) (3D).
Results: Numbers of urinary EV (particles/µmol urine creatinine) were significantly increased in ‘AKI progressor’ urine compared with control urine. Urinary EV from ‘AKI progressors’ had a distinct miRNA signature (e.g. ↑ miR-25-3p), with network mapping associating these miRNAs to pathways of: (i) cell death; and (ii) dysregulated lipid metabolism – hallmarks of ferroptotic death signalling. In co-culture studies, urinary EV from ‘AKI progressors’ induced significantly increased PTEC ferroptosis (↑ lipid peroxidation) and tubuloid ferroptosis (↑ ACSL4 expression) compared with ‘AKI recovery’ and control urinary EV.
Conclusions: We identify urinary EVs and their miRNA cargo as readily-accessible, non-invasive prognostic biomarkers of tubular ferroptosis, with utility to define which people with AKI will progress to CKD.
Presentation Slides PDF – Click here
Biography:
Dr Andrew Kassianos is a Senior Scientist at the Conjoint Kidney Research Laboratory, Queensland Health – located at the QIMR Berghofer Medical Research Institute. Dr Kassianos has contributed to the fields of nephrology and immunology with 45 publications (>2300 citations; ~50 citations/paper; h–index 22; 5 editorial commentaries) and >50 presentations at premier local, national and international meetings, including invited keynote lectures. Dr Kassianos has a continued record of success in attracting competitive research funding, including an NHMRC Dora Lush PhD Scholarship (2007-2010), an RBWH Foundation Post-Doctoral Fellowship (2012-2014) and two NHMRC Project Grants as CIA (2016-2019; 2019-2022). Overall, he has been awarded >$2 million in funding from competitive grant schemes. Dr Kassianos’ current program of research is focussed on understanding the cell-cell communication mechanisms (i.e. extracellular vesicle signalling) between discrete kidney cell and immune cell populations and the therapeutic potential of check-point targeting this cross-talk in disease progression.