IL-6 induces mitochondrial ROS production and blunts NO bioavailability in human aortic endothelial cells

Area of Science:

• Cardiovascular Biology
• Cellular Physiology
• Inflammation Research

Background:

• Chronic inflammation is a key driver of endothelial dysfunction.
• Interleukin-6 (IL-6), a pro-inflammatory cytokine, is linked to cardiovascular disease risk and vascular dysfunction.
• Mechanisms linking inflammation to endothelial dysfunction, particularly the role of mitochondrial reactive oxygen species (ROS) and nitric oxide (NO) bioavailability, remain incompletely understood.

Purpose of the Study:

• To investigate the hypothesis that IL-6 induces mitochondrial ROS production and reduces NO bioavailability in endothelial cells.
• To elucidate the direct impact of IL-6 on mitochondrial ROS and NO pathways in human aortic endothelial cells (HAECs).

Main Methods:

• Human aortic endothelial cells (HAECs) were treated with IL-6, MitoTEMPOL (MT; a mitochondria-targeted antioxidant), and/or l-NAME (a nitric oxide synthase inhibitor).
• Measurements included mitochondrial ROS production and nitric oxide (NO) bioavailability under basal and acetylcholine-stimulated conditions.
• Statistical analysis involved one-way ANOVA and Bonferroni's post hoc tests.

Main Results:

• IL-6 treatment significantly increased mitochondrial ROS production in HAECs compared to controls.
• IL-6 significantly blunted NO bioavailability, both at baseline and following acetylcholine stimulation.
• MitoTEMPOL (MT) treatment effectively scavenged mitochondrial ROS and restored NO bioavailability in IL-6-treated cells.

Conclusions:

• IL-6 directly induces mitochondrial ROS production in human aortic endothelial cells.
• Increased mitochondrial ROS by IL-6 leads to impaired nitric oxide bioavailability.
• These findings provide a mechanistic link between IL-6, mitochondrial ROS, and endothelial dysfunction.