Revisiting the adipocyte: a model for integration of cytokine signaling in the regulation of energy metabolism.
Adipose tissue constitutes an extremely active endocrine organ with a network of signaling pathways enabling the organism to adapt to a wide range of different metabolic challenges, such as starvation, stress, infection, and short periods of gross energy excess. The functional pleiotropism of adipose tissue relies on its ability to synthesize and release a huge variety of hormones, cytokines, complement and growth factors, extracellular matrix proteins, and vasoactive factors, collectively termed adipokines. Obesity is associated with adipose tissue dysfunction leading to the onset of several pathologies including type 2 diabetes, dyslipidemia, nonalcoholic fatty liver, or hypertension, among others. The mechanisms underlying the development of obesity and its associated comorbidities include the hypertrophy and/or hyperplasia of adipocytes, adipose tissue inflammation, impaired extracellular matrix remodeling, and fibrosis together with an altered secretion of adipokines. Recently, the potential role of brown and beige adipose tissue in the protection against obesity has been also recognized. In contrast to white adipocytes, which store energy in the form of fat, brown and beige fat cells display energy-dissipating capacity through the promotion of triacylglycerol clearance, glucose disposal, and generation of heat for thermogenesis. Identification of the morphological and molecular changes in white, beige, and brown adipose tissue during weight gain is of utmost relevance for the identification of pharmacological targets for the treatment of obesity and its associated metabolic diseases.
Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain.
Amaia
A
Rodríguez
Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain;
Silvia
S
Ezquerro
Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain.
Leire
L
Méndez-Giménez
Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain.
Sara
S
Becerril
Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain gfruhbeck@unav.es.
Gema
G
Frühbeck
D017667:Adipocytes / Q000378:metabolism; D052437:Adipocytes, Brown / Q000378:metabolism*; D052438:Adipocytes, White / Q000378:metabolism*; D054392:Adipokines / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D050171:Dyslipidemias / Q000378:metabolism; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000378:metabolism; D008954:Models, Biological; D065626:Non-alcoholic Fatty Liver Disease / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*; D015398:Signal Transduction; D022722:Thermogenesis; D014280:Triglycerides / Q000378:metabolism; D015430:Weight Gain
D054392:Adipokines; D016207:Cytokines; D014280:Triglycerides; D005947:Glucose
adipocyte hypertrophy and hyperplasia; adipose tissue inflammation; extracellular matrix remodeling; fat browning; white and brown adipogenesis