Related Experiment Video
Updated: Aug 10, 2025
Morphological and Functional Evaluation of Axons and their Synapses during Axon Death in Drosophila melanogaster
Published on: March 16, 2020
DLK-dependent axonal mitochondrial fission drives degeneration following axotomy
Jorge Gómez-Deza1, Matthew Nebiyou1, Mor R Alkaslasi1
1Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States.
Abstract:
Currently there are no effective treatments for an array of neurodegenerative disorders to a large part because cell-based models fail to recapitulate disease. Here we developed a reproducible human iPSC-based model where laser axotomy causes retrograde axon degeneration leading to neuronal cell death. Time-lapse confocal imaging revealed that damage triggers an apoptotic wave of mitochondrial fission proceeding from the site of injury to the soma. We demonstrated that this apoptotic wave is locally initiated in the axon by dual leucine zipper kinase (DLK). We found that mitochondrial fission and resultant cell death are entirely dependent on phosphorylation of dynamin related protein 1 (DRP1) downstream of DLK, revealing a new mechanism by which DLK can drive apoptosis. Importantly, we show that CRISPR mediated Drp1 depletion protected mouse retinal ganglion neurons from degeneration after optic nerve crush. Our results provide a powerful platform for studying degeneration of human neurons, pinpoint key early events in damage related neural death and new focus for therapeutic intervention.
Insights
Researchers developed a new human cell model for neurodegenerative diseases. This model shows how axon injury triggers cell death via mitochondrial fission, offering new therapeutic targets.
Area of Science:
- Neuroscience
- Cell Biology
- Genetics
Background:
- Neurodegenerative disorders lack effective treatments due to inadequate disease models.
- Existing models fail to accurately replicate human neuronal degeneration.
Purpose of the Study:
- To develop a human iPSC-based model for studying neurodegenerative disease.
- To investigate the mechanisms of axon degeneration and neuronal cell death.
Main Methods:
- Human induced pluripotent stem cells (iPSCs) were used to create a neuronal model.
- Laser axotomy was employed to induce retrograde axon degeneration.
- Time-lapse confocal imaging and CRISPR gene editing were utilized.
Main Results:
- Axon injury initiated an apoptotic wave of mitochondrial fission.
- Dual leucine zipper kinase (DLK) locally initiated this apoptotic wave in the axon.
- Dynamin related protein 1 (DRP1) phosphorylation downstream of DLK was crucial for mitochondrial fission and cell death.
- CRISPR-mediated Drp1 depletion protected mouse retinal ganglion neurons from degeneration.
Conclusions:
- A reproducible human iPSC model for studying neuronal degeneration was established.
- A novel mechanism involving DLK and DRP1 in damage-induced apoptosis was identified.
- This research provides a new platform for therapeutic interventions in neurodegenerative diseases.
