Granulin loss of function in human mature brain organoids implicates astrocytes in TDP-43 pathology

Stem Cell Reports. 2023 Mar 14;18(3):706-719. doi: 10.1016/j.stemcr.2023.01.012. Epub 2023 Feb 23.

Abstract

Loss of function (LoF) of TAR-DNA binding protein 43 (TDP-43) and mis-localization, together with TDP-43-positive and hyperphosphorylated inclusions, are found in post-mortem tissue of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients, including those carrying LoF variants in the progranulin gene (GRN). Modeling TDP-43 pathology has been challenging in vivo and in vitro. We present a three-dimensional induced pluripotent stem cell (iPSC)-derived paradigm-mature brain organoids (mbOrg)-composed of cortical-like-astrocytes (iA) and neurons. When devoid of GRN, mbOrgs spontaneously recapitulate TDP-43 mis-localization, hyperphosphorylation, and LoF phenotypes. Mixing and matching genotypes in mbOrgs showed that GRN-/- iA are drivers for TDP-43 pathology. Finally, we rescued TDP-43 LoF by adding exogenous progranulin, demonstrating a link between TDP-43 LoF and progranulin expression. In conclusion, we present an iPSC-derived platform that shows striking features of human TDP-43 proteinopathy and provides a tool for the mechanistic modeling of TDP-43 pathology and patient-tailored therapeutic screening for FTD and ALS.

Keywords: ALS; FTD; astrocytes; iPSC; neurodegeneration; neurons; strocyte-neuronal signaling.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Amyotrophic Lateral Sclerosis* / pathology
  • Astrocytes / metabolism
  • Brain / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Frontotemporal Dementia* / genetics
  • Granulins / genetics
  • Granulins / metabolism
  • Humans
  • Mutation
  • Progranulins / genetics
  • Progranulins / metabolism

Substances

  • Granulins
  • Progranulins
  • DNA-Binding Proteins