Adipose Tissue Macrophages.

Area of Science:

• Immunology
• Metabolic Health
• Adipose Tissue Biology

Background:

• Adipose tissue macrophages (ATMs) are key immune cells in adipose tissue, implicated in obesity-associated metabolic inflammation and insulin resistance.
• The ontogeny and physiological roles of ATMs in lean individuals remain less understood.
• Understanding ATM function is crucial for metabolic health and immune balance.

Purpose of the Study:

• To elucidate the developmental origins and physiological functions of ATMs throughout life.
• To investigate the dynamic changes in ATM activity from lean to obese states.
• To identify key signaling pathways governing ATM-adipocyte interactions and adipose tissue health.

Main Methods:

• Comparative analysis of ATM populations in lean and obese adipose tissue.
• In vivo and in vitro studies on ATM-adipocyte crosstalk.
• Molecular profiling of inflammatory pathways within ATMs.

Main Results:

• ATMs are present from birth, supporting adipocyte lipolysis, mitobiogenesis, and thermogenesis in lean states.
• In adult lean adipose tissue, ATMs shift to limit thermogenesis and promote lipid storage.
• Obesity triggers pro-inflammatory responses in ATMs, including inflammasome activation, pyroptosis, and NF-κB/IRF signaling.

Conclusions:

• ATMs are lifelong residents of adipose tissue with distinct functions in lean versus obese conditions.
• ATM ontogeny and their interactions with adipocytes are critical determinants of adipose tissue health.
• Dysregulated ATM function in obesity contributes significantly to metabolic dysfunction and inflammation.