Pulsatile shear stress increased mitochondrial membrane potential: implication of Mn-SOD

Area of Science:

• Cardiovascular Biology
• Mitochondrial Physiology
• Cellular Mechanotransduction

Background:

• Mitochondrial dysfunction is a key factor in cardiovascular diseases.
• Mitochondrial membrane potential (DeltaPsi(m)) is crucial for ATP synthesis via oxidative phosphorylation.

Purpose of the Study:

• To investigate the impact of physiological pulsatile shear stress (PSS) on DeltaPsi(m) in human aortic endothelial cells (HAEC).
• To determine the role of manganese superoxide dismutase (Mn-SOD) in mediating the PSS-induced changes in DeltaPsi(m).

Main Methods:

• HAEC were subjected to PSS.
• DeltaPsi(m) was measured using the TMRM(+) probe.
• Mn-SOD expression and activity were assessed.
• Experiments involved Mn-SOD silencing and the use of a Mn-SOD mimetic (MnTMPyP).

Main Results:

• PSS significantly increased DeltaPsi(m) in a dynamic manner, returning to baseline after a period of static culture.
• PSS exposure led to significant up-regulation of Mn-SOD expression and activity.
• Silencing Mn-SOD attenuated the PSS-induced increase in DeltaPsi(m).
• MnTMPyP administration mimicked the PSS-induced DeltaPsi(m) increase.

Conclusions:

• PSS enhances mitochondrial membrane potential in HAEC.
• Mn-SOD up-regulation plays a significant role in mediating the PSS-induced increase in DeltaPsi(m).
• These findings elucidate a mechanism by which mechanical forces influence mitochondrial function relevant to cardiovascular health.