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Kidney Week

Abstract: FR-OR063

Kidney Organoid Model of Light Chain Amyloidosis

Session Information

Category: Onconephrology

  • 1700 Onconephrology

Authors

  • Afrin, Humayra, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Qamar, Usama, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Dick, Christopher J., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Leung, Nelson, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Kourelis, Taxiarchis, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Gupta, Navin R., Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background

Amyloidosis is a systemic disorder in which misfolded proteins aggregate into insoluble fibrils that deposit in tissues to cause multiorgan failure. The misfolded protein in light chain (AL) amyloidosis is immunoglobulin free light chains (FLC), which accumulate in the kidney to cause a morphologic podocyte injury that results in proteinuria and progressive kidney failure. Existing treatments for AL amyloidosis focus on reducing the circulating FLC with chemotherapy. Yet, a substantial amount of patients fail to achieve a complete or partial renal response despite markedly reduced FLC, likely due to the persistence of previously deposited amyloid fibrils. Reducing the kidney toxicity to preformed fibrils represents a paradigm-shift in treatment beyond the capacity of animal models, which fail to demonstrate prototypical glomerular amyloid deposition and podocyte dysmorphia due to inter-species differences in amyloid kinetics and clearance. To overcome this critical scientific gap, we report an entirely human model using kidney organoid derived from human pluripotent stem cells (hPSCs). We hypothesize that kidney organoids develop glomerular amyloid deposition and podocyte dysmorphia when subject to human-derived amyloidogenic fibrils.

Methods

H9 hPSCs were differentiated into kidney organoids using the Morizane protocol. On differentiation day 42, organoids were treated with GFP-tagged amyloidogenic human kappa light chain fibrils (AL09), versus their soluble or vehicle controls. Longitudinal brightfield and epifluorescent microscopy enabled GFP monitoring in organoids. Wholemount immunostaining and high magnification confocal microscopy for NPHS1, NPHS2, and phalloidin investigated for podocytopathy.

Results

Kidney organoids treated with tagged amyloidogenic fibrils manifest progressive GFP+, which co-localized with PODXL+ podocytes to reflect glomerular amyloid deposition. Amyloidogenic fibrils, unlike their soluble control, altered the Actin cytoskeleton of podocytes. Ultrastructural changes included the significant and gradual loss of slit diaphragm markers, NPHS1 and NPHS2, consistent with podocyte dysmorphia.

Conclusion

Kidney organoids model the glomerular amyloid deposition and podocyte dysmorphia seen in renal AL amyloidosis and may serve as a testing platform for paradigm-shifting treatment that reduces kidney injury independent of FLC burden.

Funding

  • Private Foundation Support

Digital Object Identifier (DOI)