Funded Grants

Investigating the role of mutations in CHCHD10 using ALS cell and zebrafish genetic models

Project Overview

CHCHD10 is a nuclear encoded mitochondrial protein of the twin Cx9C family whose cellular function remains to be fully understood. Several dominantly inherited missense mutations have been reported in patients with amyotrophic lateral sclerosis (ALS), some of which appear to be gain of function while others are haploinsufficient. In the mitochondrial intermembrane space, CHCHD10 forms a complex of unknown function with its paralogue CHCHD2, a protein that has been linked to rare cases of Parkinson disease. Using a combination of patient cell lines and novel zebrafish CRISPR models we propose to study the function of CHCHD10 and CHCHD2 and the cellular and molecular basis for pathology. Preliminary data on human fibroblasts from an ALS/FTD patient and from CRISPR/Cas9 knockouts have demonstrated that both proteins are required for aerobic metabolism, and that loss of function variants result in assembly defects in one or more of the oxidative phosphorylation (OXPHOS) complexes. Patient cells (CHCHD10R15L) challenged with an nutrient stress exhibit a severe growth defect and upregulate both a mitochondrial and endoplasmic reticulum (ER) unfolded protein response, the latter mediated through the IRE1/XBP1 pathway. We hypothesize that this might be a general response to gain or loss of function CHCHD10 variants, and we propose to test this, and to try to identify how mitochondrial stress is signaled to the cytoplasm/ER in this model. We will also use CRISPR/Cas9 editing to disrupt components of the UPR responses to test the effects in cell survival, apoptosis, and autophagy. The results of these studies will be used to inform experiments using in vivo models in zebrafish, including the characterization of motor defects, neuromuscular junction (NMJ) denervation, as well as mitochondrial dysfunction. To this end a Chchd10 and Chchd2 knockout, as well as a Chchd10P83L knockin model (analogous to the human CHCHD10P80L variant) have been created. Preliminary results suggest that loss of Chchd10, or Chchd2 or expression of the Chchd10P83L variant leads to reduced survival, weight as well as aberrant muscle histology in adult fish. We hypothesize that our cell and zebrafish models offers a unique opportunity to explore the mechanisms that culminate in neurodegeneration in patients with mutations in CHCHD10 and may likely add to the complex, and as of yet to be fully understood role, that abnormal mitochondrial play in ALS.

Principal Investigator

Gary Armstrong , Montreal Neurological Institute, McGill University

Team Members

Eric Shoubridge, Montreal Neurological Institute, McGill University

Partners and Donors

ALS Canada

Project Ongoing

Investigating the role of mutations in CHCHD10 using ALS cell and zebrafish genetic models

Program Type
Team grants
Area of research
Neurodegeneration
Disease Area
ALS
Competition
ALS Canada - Brain Canada Discovery Grants
Province
Québec
Start Date
2021
Total Grant Amount
$125,000
Health Canada Contribution
$62,500