Human proximal tubular epithelial cell-derived small extracellular vesicles mediate synchronized tubular ferroptosis in hypoxic kidney injury
Xiangju Wang,
Chang Seong Kim,
Benjamin C. Adams,
Ray Wilkinson,
Michelle M. Hill,
Alok K. Shah,
Ahmed Mohamed,
Mriga Dutt,
Monica S.Y. Ng,
Jacobus P.J. Ungerer,
Helen G. Healy,
Andrew J. Kassianos
Affiliations
Xiangju Wang
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia
Chang Seong Kim
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Department of Internal Medicine, Chonnam National University Hospital, Gwangju, Republic of Korea; Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
Benjamin C. Adams
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
Ray Wilkinson
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia; Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
Michelle M. Hill
QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Alok K. Shah
QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Ahmed Mohamed
QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Mriga Dutt
QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Monica S.Y. Ng
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
Jacobus P.J. Ungerer
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
Helen G. Healy
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
Andrew J. Kassianos
Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland, Brisbane, Queensland, Australia; Kidney Health Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia; Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia; Corresponding author. Conjoint Internal Medicine Laboratory Chemical Pathology, Pathology Queensland QIMR Berghofer Medical Research Institute Level 9, Bancroft Centre Herston, QLD, 4006, Australia.
Hypoxia is the key pathobiological trigger of tubular oxidative stress and cell death that drives the transition of acute kidney injury (AKI) to chronic kidney disease (CKD). The mitochondrial-rich proximal tubular epithelial cells (PTEC) are uniquely sensitive to hypoxia and thus, are pivotal in propagating the sustained tubular loss of AKI-to-CKD transition. Here, we examined the role of PTEC-derived small extracellular vesicles (sEV) in propagating the ‘wave of tubular death’.Ex vivo patient-derived PTEC were cultured under normoxia (21 % O2) and hypoxia (1 % O2) on Transwell inserts for isolation and analysis of sEV secreted from apical versus basolateral PTEC surfaces. Increased numbers of sEV were secreted from the apical surface of hypoxic PTEC compared with normoxic PTEC. No differences in basolateral sEV numbers were observed between culture conditions. Biological pathway analysis of hypoxic-apical sEV cargo identified distinct miRNAs linked with cellular injury pathways. In functional assays, hypoxic-apical sEV selectively induced ferroptotic cell death (↓glutathione peroxidase-4, ↑lipid peroxidation) in autologous PTEC compared with normoxic-apical sEV. The addition of ferroptosis inhibitors, ferrostatin-1 and baicalein, attenuated PTEC ferroptosis. RNAse A pretreatment of hypoxic-apical sEV also abrogated PTEC ferroptosis, demonstrating a role for sEV RNA in ferroptotic ‘wave of death’ signalling. In line with these in vitro findings, in situ immunolabelling of diagnostic kidney biopsies from AKI patients with clinical progression to CKD (AKI-to-CKD transition) showed evidence of ferroptosis propagation (increased numbers of ACSL4+ PTEC), while urine-derived sEV (usEV) from these ‘AKI-to-CKD transition’ patients triggered PTEC ferroptosis (↑lipid peroxidation) in functional studies.Our data establish PTEC-derived apical sEV and their intravesicular RNA as mediators of tubular lipid peroxidation and ferroptosis in hypoxic kidney injury. This concept of how tubular pathology is propagated from the initiating insult into a ‘wave of death’ provides novel therapeutic check-points for targeting AKI-to-CKD transition.
