Compound C Increases Sestrin2 Expression via Mitochondria-Dependent ROS Production.

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Compound C is a known inhibitor of AMP-activated protein kinase (AMPK).
• Emerging evidence suggests Compound C may have AMPK-independent cellular effects.
• Sestrin2 (SESN2) is an antioxidant enzyme induced by various cellular stresses.

Purpose of the Study:

• To investigate if Compound C induces Sestrin2 (SESN2) expression.
• To elucidate the underlying mechanism of Compound C-induced SESN2.
• To determine if Compound C's effects are mediated by AMPK inhibition.

Main Methods:

• HepG2 cells were treated with Compound C.
• SESN2 protein and mRNA levels were assessed.
• Luciferase activity assays were used to confirm transcriptional regulation.
• Reactive oxygen species (ROS) production was measured.
• Mitochondrial function was assessed using specific inhibitors and cyclosporin A.
• AMPK activity was modulated via overexpression of a constitutively active form.

Main Results:

• Compound C increased SESN2 protein and mRNA expression in a dose- and time-dependent manner.
• Transcriptional regulation of SESN2 by Compound C was confirmed.
• Compound C elevated ROS production and Nrf2 phosphorylation.
• Mitochondrial dysfunction and ROS production were implicated in SESN2 induction.
• SESN2 induction by Compound C was independent of AMPK inhibition.

Conclusions:

• Compound C alters mitochondrial function, leading to ROS production.
• ROS production subsequently triggers Nrf2 phosphorylation and SESN2 induction.
• The mechanism of Compound C-induced SESN2 is independent of AMPK inhibition.