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Abstract: TH-PO757

Targeting Membrane Lipid Peroxidation Rescues Podocyte Dysfunction in Cystinosis

Session Information

Category: Glomerular Diseases

  • 1403 Podocyte Biology

Authors

  • Berlingerio, Sante Princiero, Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Tassinari, Sarah, Universita degli Studi di Torino Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Torino, Italy
  • Bondue, Tjessa, Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Ferrulli, Angela, Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Lismont, Celien, Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Fransen, Marc, Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Cairoli, Sara, Ospedale Pediatrico Bambino Gesu, Roma, Lazio, Italy
  • Arcolino, Fanny Oliveira, Amsterdam Universitair Medische Centra, Duivendrecht, Noord-Holland, Netherlands
  • Van den heuvel, Lambertus P.W.J., Katholieke Universiteit Leuven Groep Biomedische Wetenschappen, Leuven, Flanders, Belgium
  • Bussolati, Benedetta, Universita degli Studi di Torino Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Torino, Italy
  • Levtchenko, Elena, Amsterdam Universitair Medische Centra, Duivendrecht, Noord-Holland, Netherlands
Background

Cystinosis is a rare, incurable, autosomal recessive lysosomal storage disease caused by mutations in the CTNS-/- gene and leading to lysosomal cystine accumulation in all cells of the body. While cystinosis is considered as a prototype of proximal tubular dysfunction, the disease also affects glomerular podocytes and presents with increased podocyte losses into urine and glomerular proteinuria at early disease stages. Cysteamine, the current standard of care treatment, decreases lysosomal cystine accumulation but does not reverse podocyte injury. Thus, we aimed at investigating other pathogenic mechanisms than mere cystine accumulation involved in glomerular dysfunction in cystinosis.

Methods

Immortalized cystinosis patient-derived podocytes, healthy podocytes and CTNS-/- knockdown podocytes were used and the results were validated in our newly in-house developed fluorescent ctns-/- zebrafish larvae model (l-fabp:DBP-eGFP;CTNS). To understand the impaired podocyte functionality, static and dynamic permeability assay, tracer metabolomics analysis (LC-MS), flow cytometry, RT-qPCR, western blot, chemical and dynamic roGFP2 redox-sensing fluorescent probes were used.

Results

Cystinosis podocytes present decreased adhesion, increased permeability and enhanced ferroptosis cell death caused by an accumulation of mitochondrial ROS-driven lipid membrane peroxides. Moreover, these cells show fragmented mitochondrial network with impaired energy and TCA cycle metabolism and decreased expression of superoxide scavenging enzyme SOD2. Targeting mitochondrial ROS with MitoTEMPO in combination with cysteamine or lipid peroxidation with Liproxstatin-1 improved podocytes dysfunction in vitro and rescued proteinuria in cystinosis zebrafish larvae.

Conclusion

Mitochondrial dysfunction leading to increased ROS production and subsequent lipid peroxidation drive podocyte detachment and ferroptosis and plays a key role in podocyte injury in cystinosis. Targeting these mechanisms represents a new therapeutic prospective for nephropathic cystinosis.