Related Experiment Videos
Model for hypoxic pulmonary vasoconstriction involving mitochondrial oxygen sensing.
G B Waypa1, N S Chandel, P T Schumacker
1Department of Medicine, The University of Chicago, Chicago, Ill, USA.
Circulation Research
|June 23, 2001
Summary
Mitochondria act as oxygen sensors in hypoxic pulmonary vasoconstriction (HPV). Inhibiting the mitochondrial electron transport chain and reactive oxygen species (ROS) abolished HPV, indicating ROS generated by mitochondria are key signaling molecules.
Area of Science:
- Physiology
- Cell Biology
- Biochemistry
Background:
- Hypoxic pulmonary vasoconstriction (HPV) is a critical physiological response.
- The precise oxygen sensing mechanism in HPV remains incompletely understood.
Purpose of the Study:
- To investigate the role of mitochondria as oxygen sensors in HPV.
- To determine if mitochondrial reactive oxygen species (ROS) act as signaling molecules in HPV.
Main Methods:
- Utilized buffer-perfused rat lungs and cultured pulmonary artery (PA) myocytes.
- Employed inhibitors of the mitochondrial electron transport chain (ETC) and antioxidants.
- Assessed cellular responses to hypoxia and U46619, and measured ROS production.
Main Results:
- Inhibition of proximal ETC (rotenone, myxothiazol) abolished HPV, while distal ETC inhibition (cyanide, antimycin A) did not.
- Mutant PA myocytes lacking mitochondrial ETC lost their hypoxic response.
- Antioxidants abolished HPV, and ROS production (H2O2) increased during hypoxia, implicating mitochondria.
Conclusions:
- Mitochondria function as the primary oxygen sensors in HPV.
- ROS generated by the proximal ETC act as crucial second messengers in this response.
- Mitochondrial ATP production is not required for HPV.