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High-resolution Respirometry to Measure Mitochondrial Function of Intact Beta Cells in the Presence of Natural Compounds
Published on: January 23, 2018
Glucose modulates respiratory complex I activity in response to acute mitochondrial dysfunction.
Giuseppe Cannino1, Riyad El-Khoury, Marja Pirinen
1Institute of Biomedical Technology and Centre for Laboratory Medicine, Tampere University Hospital, University of Tampere, 33014 Tampere, Finland.
The Journal of Biological Chemistry
|September 26, 2012
Summary
This study reveals how cells adapt to mitochondrial dysfunction. Introducing specific enzymes showed that Complex I plays a key role in regulating cellular metabolism during respiratory chain defects.
Area of Science:
- Cell Biology
- Biochemistry
- Mitochondrial Physiology
Background:
- Coordination between glycolysis and respiration is crucial for cellular energy production.
- Mechanisms sensing respiratory chain defects and adapting mitochondrial function remain largely unknown.
Purpose of the Study:
- Investigate regulatory mechanisms linking glycolysis and respiration.
- Elucidate cellular responses to mitochondrial dysfunction using engineered enzymes.
Main Methods:
- Utilized cultured human HEK293T cells.
- Introduced respiratory bypass enzymes, including NDI1 (alternative NADH dehydrogenase) and AOX (alternative oxidase).
- Studied mitochondrial responses to respiratory chain inhibition under various conditions (permeabilized vs. intact cells, glucose availability).
Main Results:
- NDI1 and AOX bypassed specific respiratory chain complex inhibitions.
- Glucose suppressed AOX bypass effects in intact cells, but not NDI1 bypass effects.
- NDI1 reversed glucose suppression of AOX respiration, identifying Complex I as a key regulatory target.
- Rapid Complex I down-regulation acts as an "emergency shutdown" system, independent of HIF1, superoxide, or ATP synthase.
Conclusions:
- Discovered a novel adaptive pathway for mitochondrial dysfunction.
- Complex I is a critical regulator sensing and responding to oxidative phosphorylation defects.
- Findings offer potential therapeutic strategies for diseases linked to mitochondrial dysfunction.
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