Deoxysphingolipids - atypical skeletal muscle lipids related to insulin resistance in humans that decrease insulin...

Area of Science:

• Metabolism and Endocrinology
• Molecular Biology

Background:

• Sphingolipids are implicated in skeletal muscle insulin resistance.
• 1-Deoxysphingolipids (dSL) are atypical sphingolipids found in individuals with type 2 diabetes and are known to impair pancreatic beta-cell function.
• The role of dSL in human skeletal muscle insulin resistance remains unclear.

Purpose of the Study:

• To investigate the role of 1-Deoxysphingolipids (dSL) in human skeletal muscle insulin resistance.
• To determine if dSL levels are altered in obesity and type 2 diabetes.
• To explore the impact of dSL on insulin sensitivity and signaling pathways in human muscle.

Main Methods:

• Quantification of dSL species in skeletal muscle biopsies from lean, obese, and type 2 diabetic individuals.
• Analysis of the relationship between muscle dSL content and insulin sensitivity.
• Assessment of dSL effects on primary human myotubes, including inflammation, AMPK phosphorylation, and insulin signaling.
• Evaluation of changes in muscle dSL content following a weight loss and exercise intervention.

Main Results:

• dSL species were significantly elevated in the muscle of individuals with obesity and type 2 diabetes compared to lean individuals and athletes.
• Muscle dSL content was inversely correlated with insulin sensitivity.
• Intervention including weight loss and exercise led to a significant reduction in muscle dSL content in obese individuals.
• In primary human myotubes, increased dSL content decreased insulin sensitivity, increased inflammation, reduced AMPK phosphorylation, and altered insulin signaling.

Conclusions:

• 1-Deoxysphingolipids (dSL) play a significant role in human skeletal muscle insulin resistance.
• Elevated dSL levels are associated with obesity and type 2 diabetes.
• dSL may represent a viable therapeutic target for preventing and treating type 2 diabetes.