White adipose tissue (WAT) can dynamically expand and remodel through adipocyte hypertrophy and hyperplasia. The relative contribution of these 2 mechanisms to WAT expansion is a critical determinant of WAT function and dysfunction in obesity. However, little is known about the signaling systems that determine the mechanisms of WAT expansion. Here, we show that the GPCR LPA4 selectively activates Gα12/13 proteins in adipocytes and limits continuous remodeling and healthy expansion of WAT. LPA4-KO mice showed enhanced expression of mitochondrial and adipogenesis genes and reduced levels of inhibitory phosphorylation of PPARγ in WAT, along with increased production of adiponectin. Furthermore, LPA4-KO mice showed metabolically healthy obese phenotypes in a diet-induced obesity model, with continuous WAT expansion, as well as protection from WAT inflammation, hepatosteatosis, and insulin resistance. These findings unravel a potentially new signaling system that underlies WAT plasticity and expandability, providing a promising therapeutic approach for obesity-related metabolic disorders.
Keisuke Yanagida, Hidemitsu Igarashi, Daisuke Yasuda, Daiki Kobayashi, Takayo Ohto-Nakanishi, Noriyuki Akahoshi, Atsushi Sekiba, Tsudoi Toyoda, Tomoko Ishijima, Yuji Nakai, Nobuhiro Shojima, Naoto Kubota, Keiko Abe, Takashi Kadowaki, Satoshi Ishii, Takao Shimizu