Journal Article

Adipocyte cannabinoid receptor CB1 regulates energy homeostasis and alternatively activated macrophages

Srivastava, Raj Kamal, Marsicano, Giovanni, Sassmann, Antonia, Giordano, Antonio, Makriyannis, Alexandros, Bindila, Laura, Cinti, Saverio, Mancini, Giacomo, Quarta, Carmelo, Schwitter, Claudia, Vemuri, V. Kiran, Monory, Krisztina, Ruiz de Azua, Inigo, Pagotto, Uberto, Nisoli, Enzo, Cardinal, Pierre, Conrad, Andrea, Zingaretti, Cristina Maria, Offermanns, Stefan, Cota, Daniela, Mendez-Lago, Maria, Rey, Alejandro Aparisi, Wettschureck, Nina, Lutz, Beat, Tedesco, Laura, Hartwig, Jens

2017

Overview

Dysregulated adipocyte physiology leads to imbalanced energy storage, obesity, and associated diseases, imposing a costly burden on current health care. Cannabinoid receptor type-1 (CB1) plays a crucial role in controlling energy metabolism through central and peripheral mechanisms. In this work, adipocyte-specific inducible deletion of the CB1 gene (Ati-CB1-KO) was sufficient to protect adult mice from diet-induced obesity and associated metabolic alterations and to reverse the phenotype in already obese mice. Compared with controls, Ati-CB1-KO mice showed decreased body weight, reduced total adiposity, improved insulin sensitivity, enhanced energy expenditure, and fat depot-specific cellular remodeling toward lowered energy storage capacity and browning of white adipocytes. These changes were associated with an increase in alternatively activated macrophages concomitant with enhanced sympathetic tone in adipose tissue. Remarkably, these alterations preceded the appearance of differences in body weight, highlighting the causal relation between the loss of CB1 and the triggering of metabolic reprogramming in adipose tissues. Finally, the lean phenotype of Ati-CB1-KO mice and the increase in alternatively activated macrophages in adipose tissue were also present at thermoneutral conditions. Our data provide compelling evidence for a crosstalk among adipocytes, immune cells, and the sympathetic nervous system (SNS), wherein CB1 plays a key regulatory role.

• Publisher: American Society for Clinical Investigation
• Subject: Adipocytes / Adipocytes - metabolism / Adipose tissue / Adipose Tissue, White - immunology / Adipose Tissue, White - metabolism / Adipose Tissue, White - pathology / Animals / Biomedical research / Body Weight / Cannabinoid CB1 receptors / Cannabinoids / Clonal deletion / Diabetes / Energy balance / Energy expenditure / Energy Intake / Energy Metabolism / Energy storage / Gene deletion / Genotype & phenotype / Health aspects / Homeostasis / Insulin / Macrophage Activation / Macrophages / Macrophages - physiology / Male / Metabolism / Mice, Inbred C57BL / Mice, Knockout / Obesity / Obesity - immunology / Obesity - metabolism / Organ Specificity / Physiology / Receptor, Cannabinoid, CB1 - physiology / Regulation / Rodents / Sympathetic nervous system / Thermogenesis / Transcriptome / Weight control