FBF1 deficiency promotes beiging and healthy expansion of white adipose tissue.

Preadipocytes dynamically produce sensory cilia. However, the role of primary cilia in preadipocyte differentiation and adipose homeostasis remains poorly understood. We previously identified transition fiber component FBF1 as an essential player in controlling selective cilia import. Here, we establish Fbf1tm1a/tm1a mice and discover that Fbf1tm1a/tm1a mice develop severe obesity, but surprisingly, are not predisposed to adverse metabolic complications. Obese Fbf1tm1a/tm1a mice possess unexpectedly healthy white fat tissue characterized by spontaneous upregulated beiging, hyperplasia but not hypertrophy, and low inflammation along the lifetime. Mechanistically, FBF1 governs preadipocyte differentiation by constraining the beiging program through an AKAP9-dependent, cilia-regulated PKA signaling, while recruiting the BBS chaperonin to transition fibers to suppress the hedgehog signaling-dependent adipogenic program. Remarkably, obese Fbf1tm1a/tm1a mice further fed a high-fat diet are protected from diabetes and premature death. We reveal a central role for primary cilia in the fate determination of preadipocytes and the generation of metabolically healthy fat tissue.