Human iPSC models of neuronal ceroid lipofuscinosis capture distinct effects of TPP1 and CLN3 mutations on the endocytic pathway

Hum Mol Genet. 2014 Apr 15;23(8):2005-22. doi: 10.1093/hmg/ddt596. Epub 2013 Nov 23.

Abstract

Neuronal ceroid lipofuscinosis (NCL) comprises ∼13 genetically distinct lysosomal disorders primarily affecting the central nervous system. Here we report successful reprograming of patient fibroblasts into induced pluripotent stem cells (iPSCs) for the two most common NCL subtypes: classic late-infantile NCL, caused by TPP1(CLN2) mutation, and juvenile NCL, caused by CLN3 mutation. CLN2/TPP1- and CLN3-iPSCs displayed overlapping but distinct biochemical and morphological abnormalities within the endosomal-lysosomal system. In neuronal derivatives, further abnormalities were observed in mitochondria, Golgi and endoplasmic reticulum. While lysosomal storage was undetectable in iPSCs, progressive disease subtype-specific storage material was evident upon neural differentiation and was rescued by reintroducing the non-mutated NCL proteins. In proof-of-concept studies, we further documented differential effects of potential small molecule TPP1 activity inducers. Fenofibrate and gemfibrozil, previously reported to induce TPP1 activity in control cells, failed to increase TPP1 activity in patient iPSC-derived neural progenitor cells. Conversely, nonsense suppression by PTC124 resulted in both an increase of TPP1 activity and attenuation of neuropathology in patient iPSC-derived neural progenitor cells. This study therefore documents the high value of this powerful new set of tools for improved drug screening and for investigating early mechanisms driving NCL pathogenesis.

Publication types

  • Comparative Study

MeSH terms

  • Aminopeptidases / genetics*
  • Aminopeptidases / metabolism
  • Blotting, Western
  • Case-Control Studies
  • Cell Proliferation
  • Cells, Cultured
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / genetics*
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / metabolism
  • Electrophysiology
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism
  • Fenofibrate / pharmacology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Gemfibrozil / pharmacology
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism
  • Humans
  • Immunoenzyme Techniques
  • Induced Pluripotent Stem Cells / drug effects
  • Induced Pluripotent Stem Cells / metabolism*
  • Induced Pluripotent Stem Cells / pathology
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Membrane Glycoproteins / genetics*
  • Membrane Glycoproteins / metabolism
  • Models, Neurological*
  • Molecular Chaperones / genetics*
  • Molecular Chaperones / metabolism
  • Mutation / genetics*
  • Neuronal Ceroid-Lipofuscinoses / genetics*
  • Neuronal Ceroid-Lipofuscinoses / metabolism
  • Neuronal Ceroid-Lipofuscinoses / pathology
  • Neurons / drug effects
  • Neurons / metabolism
  • Neurons / pathology
  • Serine Proteases / genetics*
  • Serine Proteases / metabolism

Substances

  • CLN3 protein, human
  • Membrane Glycoproteins
  • Molecular Chaperones
  • Serine Proteases
  • Aminopeptidases
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
  • tripeptidyl-peptidase 1
  • Gemfibrozil
  • Fenofibrate