Hematopoietic-Derived Galectin-3 Causes Cellular and Systemic Insulin Resistance

Area of Science:

• Immunology
• Metabolic Diseases
• Molecular Biology

Background:

• Obesity leads to chronic inflammation in insulin target tissues, causing insulin resistance.
• Galectin-3 (Gal3), a macrophage-secreted lectin, is elevated in obesity and linked to insulin resistance.

Purpose of the Study:

• To investigate the role of Galectin-3 (Gal3) in obesity-induced insulin resistance.
• To explore Gal3's direct interaction with the insulin receptor (IR) and its signaling pathways.

Main Methods:

• Administering Gal3 to mice to induce insulin resistance and glucose intolerance.
• Inhibiting Gal3 function genetically and pharmacologically in obese mice.
• In vitro studies on Gal3's effects on macrophage chemotaxis, glucose uptake in myocytes and adipocytes, and glucose output in hepatocytes.
• Assessing Gal3's direct binding to the insulin receptor (IR) and its downstream signaling.

Main Results:

• Gal3 administration caused insulin resistance and glucose intolerance in mice.
• Gal3 inhibition improved insulin sensitivity in obese mice.
• In vitro, Gal3 enhanced macrophage migration, reduced glucose uptake in muscle and fat cells, and impaired liver glucose regulation.
• Gal3 directly binds to the insulin receptor (IR), inhibiting its signaling.

Conclusions:

• Galectin-3 (Gal3) plays a critical role in mediating insulin resistance in hepatocytes, adipocytes, and myocytes.
• Gal3 links inflammatory processes to reduced insulin sensitivity.
• Inhibiting Gal3 presents a potential therapeutic strategy for treating insulin resistance and related metabolic disorders.