Conjugated linoleic acid is a preferential substrate for fatty acid nitration

Area of Science:

• Biochemistry
• Molecular Biology
• Physiology

Background:

• Oxidation and nitration of unsaturated fatty acids by nitrogen oxides create electrophilic derivatives.
• These derivatives can alter protein function through post-translational modifications.
• Biological mechanisms and product structures of fatty acid nitration require further definition.

Purpose of the Study:

• To identify the primary endogenous substrate for fatty acid nitration.
• To elucidate the mechanisms and products of conjugated linoleic acid (CLA) nitration.
• To investigate the biological relevance of nitroalkene derivatives in vivo.

Main Methods:

• In vitro and in vivo nitration assays using conjugated linoleic acid (CLA) and bis-allylic linoleic acid.
• Analysis of nitration products in plasma and tissues.
• Assessment of heme oxygenase-1 (HO-1) expression following dietary CLA and nitrite supplementation in rodents.

Main Results:

• Conjugated linoleic acid (CLA) is the primary endogenous substrate for fatty acid nitration, with significantly higher product yields compared to linoleic acid.
• Multiple mechanisms, including mitochondrial, macrophage, and gastric acid catalysis, contribute to CLA nitration.
• Nitroalkene derivatives of CLA are detected in healthy human plasma and increase during ischemia reperfusion.
• Dietary supplementation elevates nitro-CLA levels and induces HO-1 expression in the colonic epithelium.

Conclusions:

• Metabolic and inflammatory processes generate electrophilic nitroalkene derivatives from CLA.
• These derivatives can modulate adaptive cell signaling pathways, such as HO-1 induction.
• Fatty acid nitration products play a role in physiological and pathological conditions, including inflammation and ischemia reperfusion.