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Updated: Nov 11, 2025
In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice
Published on: November 22, 2017
NIX Mediates Mitophagy in Spinal Cord Injury in Rats by Interacting with LC3
Piming Nie1, Honggang Wang2, Datang Yu1,3
1Department of Orthopedics, Xinqiao Hospital, Third Military Medical University, 83 Xinqiao Main Street, Chongqing, 400037, China.
Abstract:
Excessive mitophagy plays a role in neuronal death in spinal cord injury (SCI), its molecular regulation remains largely unknown. The present study aims to determine the role of NIX, a member of a unique subfamily of death-inducing mitochondrial proteins, in the regulation of mitophagy in SCI. Here we show that NIX is highly upregulated in SCI and hypoxia, and localized to mitochondria. The mitochondria-bound NIX interacts with autophagosome-localized LC3 (Microtubule-associated protein 1 light chain 3) to form a mitochondria-NIX-LC3-autophagosome complex, resulting in excessive mitophagy in SCI. Downregulation of NIX by RNA interference restores the function of mitochondria in spinal cord neurons under hypoxia. Importantly, inhibition of NIX improves recovery of locomotor function in rats after SCI. The present study demonstrates that NIX interacts with LC3 to activate excessive mitophagy in SCI. Inhibition of NIX is therefore likely a neuroprotective strategy.
Insights
Excessive mitophagy contributes to neuronal death after spinal cord injury (SCI). Researchers found that NIX protein drives this process, and inhibiting NIX promotes recovery and neuroprotection in SCI.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Excessive mitophagy is implicated in neuronal death following spinal cord injury (SCI).
- The precise molecular mechanisms regulating mitophagy in SCI are not fully understood.
Purpose of the Study:
- To investigate the role of NIX (a mitochondrial protein) in regulating mitophagy in the context of SCI.
- To explore NIX as a potential therapeutic target for SCI.
Main Methods:
- Examined NIX expression and localization in SCI and hypoxia models.
- Investigated the interaction between NIX and LC3 (Microtubule-associated protein 1 light chain 3).
- Utilized RNA interference to downregulate NIX and assessed mitochondrial function and locomotor recovery in SCI rat models.
Main Results:
- NIX expression was significantly upregulated in SCI and hypoxia, localizing to mitochondria.
- Mitochondria-bound NIX was found to interact with LC3, forming a complex that drives excessive mitophagy.
- Downregulation of NIX improved mitochondrial function in hypoxic spinal cord neurons and enhanced locomotor recovery in rats post-SCI.
Conclusions:
- NIX directly interacts with LC3 to mediate excessive mitophagy in spinal cord injury.
- Inhibiting NIX presents a promising neuroprotective strategy for treating spinal cord injury.
