Microglial Lipid Droplet Accumulation: A Pathological Nexus Between Obesity and Depression

Area of Science:

• Neuroscience
• Metabolic Disorders
• Immunology

Background:

• High-fat diets (HFD) are linked to depressive behaviors, but mechanisms are unclear.
• Microglia-mediated neuroinflammation and lipid droplet (LD) accumulation are implicated in depression.
• This study investigates microglial LDs and neuroinflammation in HFD-induced depression.

Purpose of the Study:

• To examine microglial lipid droplet accumulation in diet-induced obesity (DIO).
• To assess the role of neuroinflammation in HFD-induced depressive behaviors.
• To investigate the neurotoxic potential of microglia from DIO mice.

Main Methods:

• Compared diet-induced obese (DIO) mice with control (Con) mice.
• Assessed depressive behaviors, hippocampal damage, and microglial activation.
• Quantified microglial lipid droplets (LDs) in vivo and in vitro; performed lipidomics.

Main Results:

• DIO mice showed depressive behaviors, hippocampal damage, and neuroinflammation.
• DIO microglia exhibited increased neurotoxicity toward hippocampal neurons.
• Increased LD accumulation and altered lipid metabolism were observed in DIO microglia.

Conclusions:

• Diet-induced obesity causes depressive behaviors linked to neuroinflammation and LD accumulation in microglia.
• Lipid-laden microglia contribute to obesity-depression link via neuroinflammation.
• Lipid metabolic dysregulation in microglia is a key factor.