Protection against diet-induced obesity by a single-point mutation in Kir2.1 channels

Area of Science:

• Biomedical Research
• Metabolic Disorders
• Molecular Biology

Background:

• High-fat diet (HFD)-induced obesity is a major global health issue.
• Palmitic acid (PA), common in obesity, negatively regulates Kir2.1 ion channels.
• Kir2.1 dysfunction impacts vascular function and metabolic health.

Purpose of the Study:

• To investigate the role of Kir2.1 ion channels in HFD-induced obesity.
• To determine if a Kir2.1 L222I mutation confers resistance to HFD-induced obesity.
• To explore the molecular mechanisms underlying Kir2.1 regulation by palmitic acid and its impact on metabolism.

Main Methods:

• Generated a global knock-in CRISPR mouse model with the Kir2.1 L222I mutation.
• Administered HFD to wild-type and Kir2.1 L222I mutant mice.
• Assessed body weight, body composition (lean mass, fat mass), adiposity, physical activity, and energy expenditure.
• Performed flow-induced vasodilation (FIV) assays.
• Conducted metabolomic analysis of adipose tissue.

Main Results:

• Kir2.1 L222I mutant mice showed significant resistance to HFD-induced weight gain and adiposity, independent of caloric intake.
• Mutant mice exhibited increased lean mass and decreased fat mass in visceral and subcutaneous white adipose tissue (WAT) and intrascapular brown adipose tissue (BAT).
• Palmitic acid was identified as a novel negative regulator of Kir2.1, and the L222I mutation protected against this suppression, preserving FIV and enhancing energy expenditure.

Conclusions:

• The Kir2.1 L222I mutation confers substantial protection against HFD-induced obesity.
• Kir2.1 channels, regulated by palmitic acid, are critical players in metabolic homeostasis and vascular function.
• Targeting Kir2.1 channels represents a promising therapeutic strategy for obesity and associated metabolic disorders.