Patient-iPSC-Derived Kidney Organoids Show Functional Validation of a Ciliopathic Renal Phenotype and Reveal Underlying Pathogenetic Mechanisms

Am J Hum Genet. 2018 May 3;102(5):816-831. doi: 10.1016/j.ajhg.2018.03.014. Epub 2018 Apr 26.

Abstract

Despite the increasing diagnostic rate of genomic sequencing, the genetic basis of more than 50% of heritable kidney disease remains unresolved. Kidney organoids differentiated from induced pluripotent stem cells (iPSCs) of individuals affected by inherited renal disease represent a potential, but unvalidated, platform for the functional validation of novel gene variants and investigation of underlying pathogenetic mechanisms. In this study, trio whole-exome sequencing of a prospectively identified nephronophthisis (NPHP) proband and her parents identified compound-heterozygous variants in IFT140, a gene previously associated with NPHP-related ciliopathies. IFT140 plays a key role in retrograde intraflagellar transport, but the precise downstream cellular mechanisms responsible for disease presentation remain unknown. A one-step reprogramming and gene-editing protocol was used to derive both uncorrected proband iPSCs and isogenic gene-corrected iPSCs, which were differentiated to kidney organoids. Proband organoid tubules demonstrated shortened, club-shaped primary cilia, whereas gene correction rescued this phenotype. Differential expression analysis of epithelial cells isolated from organoids suggested downregulation of genes associated with apicobasal polarity, cell-cell junctions, and dynein motor assembly in proband epithelial cells. Matrigel cyst cultures confirmed a polarization defect in proband versus gene-corrected renal epithelium. As such, this study represents a "proof of concept" for using proband-derived iPSCs to model renal disease and illustrates dysfunctional cellular pathways beyond the primary cilium in the setting of IFT140 mutations, which are established for other NPHP genotypes.

Keywords: CRISPR/Cas9; IFT140; cilia; functional genomics; gene correction; induced pluripotent stem cells; kidney organoid; nephronophthisis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Cells, Cultured
  • Cellular Reprogramming / genetics
  • Cerebellar Ataxia / genetics
  • Cilia / pathology*
  • Epithelial Cells / metabolism
  • Female
  • Fibroblasts / pathology
  • Flagella / metabolism
  • Gene Editing
  • Gene Expression Profiling
  • Heterozygote
  • Humans
  • Induced Pluripotent Stem Cells / metabolism*
  • Induced Pluripotent Stem Cells / pathology
  • Kidney / diagnostic imaging
  • Kidney / pathology*
  • Organoids / pathology*
  • Phenotype
  • RNA Stability / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reproducibility of Results
  • Retinitis Pigmentosa / genetics
  • Spheroids, Cellular / metabolism
  • Spheroids, Cellular / pathology
  • Whole Exome Sequencing

Substances

  • Carrier Proteins
  • IFT140 protein, human
  • RNA, Messenger

Supplementary concepts

  • Mainzer-Saldino Disease