Adipocyte Xbp1s overexpression reduces fat mass but not lifespan. (A) Adipocyte Xbp1s overexpression led to reduction of bodyweight (n = 4). (B) Overexpression of Xbp1s in adipocytes reduced fat mass (n = 6). (C) Overexpression of Xbp1s led to reduction of fat depot mass (n = 9–10). (D) Representative H&E staining image of WATs. Scale bar, 200 μM. (E) Overexpression of Xbp1s in adipocytes caused lower levels of free fatty acids and ketone bodies under fasted condition (n = 6). (F) Overexpression of Xbp1s in adipocytes did not change insulin levels under fasted condition (n = 6). (G) Lifespan of male mice on Dox chow (n = 34 for WT, n = 24 for FIXs). (H) Representative H&E staining image of WATs from 40 weeks old male mice that were maintained on Dox chow from 7 weeks of age. Scale bar 100 μM, Data were analyzed with two-tailed Student t test. *, p < 0.05; **, p < 0.01, ***, p < 0.001. Error bars denote SEM.