ATOH1/RFX1/RFX3 transcription factors facilitate the differentiation and characterisation of inner ear hair cell-like cells from patient-specific induced pluripotent stem cells harbouring A8344G mutation of mitochondrial DNA

Cell Death Dis. 2018 Apr 1;9(4):437. doi: 10.1038/s41419-018-0488-y.

Abstract

Degeneration or loss of inner ear hair cells (HCs) is irreversible and results in sensorineural hearing loss (SHL). Human-induced pluripotent stem cells (hiPSCs) have been employed in disease modelling and cell therapy. Here, we propose a transcription factor (TF)-driven approach using ATOH1 and regulatory factor of x-box (RFX) genes to generate HC-like cells from hiPSCs. Our results suggest that ATOH1/RFX1/RFX3 could significantly increase the differentiation capacity of iPSCs into MYO7AmCherry-positive cells, upregulate the mRNA expression levels of HC-related genes and promote the differentiation of HCs with more mature stereociliary bundles. To model the molecular and stereociliary structural changes involved in HC dysfunction in SHL, we further used ATOH1/RFX1/RFX3 to differentiate HC-like cells from the iPSCs from patients with myoclonus epilepsy associated with ragged-red fibres (MERRF) syndrome, which is caused by A8344G mutation of mitochondrial DNA (mtDNA), and characterised by myoclonus epilepsy, ataxia and SHL. Compared with isogenic iPSCs, MERRF-iPSCs possessed ~42-44% mtDNA with A8344G mutation and exhibited significantly elevated reactive oxygen species (ROS) production and CAT gene expression. Furthermore, MERRF-iPSC-differentiated HC-like cells exhibited significantly elevated ROS levels and MnSOD and CAT gene expression. These MERRF-HCs that had more single cilia with a shorter length could be observed only by using a non-TF method, but those with fewer stereociliary bundle-like protrusions than isogenic iPSCs-differentiated-HC-like cells could be further observed using ATOH1/RFX1/RFX3 TFs. We further analysed and compared the whole transcriptome of M1ctrl-HCs and M1-HCs after treatment with ATOH1 or ATOH1/RFX1/RFX3. We revealed that the HC-related gene transcripts in M1ctrl-iPSCs had a significantly higher tendency to be activated by ATOH1/RFX1/RFX3 than M1-iPSCs. The ATOH1/RFX1/RFX3 TF-driven approach for the differentiation of HC-like cells from iPSCs is an efficient and promising strategy for the disease modelling of SHL and can be employed in future therapeutic strategies to treat SHL patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Catalase / genetics
  • Catalase / metabolism
  • Cell Differentiation*
  • Cilia / physiology
  • DNA, Mitochondrial / genetics
  • Embryoid Bodies / cytology
  • Embryoid Bodies / metabolism
  • Female
  • Hair Cells, Auditory, Inner / cytology
  • Hair Cells, Auditory, Inner / metabolism*
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • MERRF Syndrome / complications
  • MERRF Syndrome / pathology*
  • Myosin VIIa / genetics
  • Myosin VIIa / metabolism
  • Point Mutation
  • Reactive Oxygen Species / metabolism
  • Regulatory Factor X Transcription Factors / genetics*
  • Regulatory Factor X Transcription Factors / metabolism
  • Regulatory Factor X1 / genetics*
  • Regulatory Factor X1 / metabolism
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism

Substances

  • ATOH1 protein, human
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA, Mitochondrial
  • MYO7A protein, human
  • Myosin VIIa
  • RFX1 protein, human
  • RFX3 protein, human
  • Reactive Oxygen Species
  • Regulatory Factor X Transcription Factors
  • Regulatory Factor X1
  • Catalase
  • Superoxide Dismutase