Fig. 7: FNDC4–GPR116 axis response to anti-diabetic interventions in humans and mice positively correlates with improvements in insulin sensitivity after the intervention.

Quantification of serum sFNDC4 protein in paired samples of individuals who underwent weight loss intervention by bariatric surgery (BS) a (n = 26 humans), b (n = 14 humans), or c (n = 24 humans), d (n = 23 humans) diet and exercise. Statistics represent paired two-tailed t test. e–g RT-qPCR quantification of GPR116 mRNA at the indicated groups. ND non-diabetic, T2D type 2 diabetes, Obese-IGT/IIT: impaired glucose tolerance/insulin tolerance (cross-sectional study Leipzig), BS bariatric surgery. n = human and the number of individuals is indicated on the graphs. For e, an unpaired two-tailed t test was used. For f, g, a paired two-tailed t test was used. h, i RT-qPCR quantification of Fndc4 and Gpr116 at the indicated tissues in mice ad libitum (AL), intermittent fasting (IF), or chow and HFD (45% fat) diet and caloric restriction (CR) upon HFD (45% fat). j Quantification of plasma sFNDC4 ng/ml at the indicated groups. Blood was collected from the central vein after decapitation (trunk). For h–j, n = mice and the exact number of mice per group is shown on the graphs. Statistics represent an unpaired two-tailed t test. In e, h–j, bars represent mean ± SEM. a–d and f, g: subjects’ information are shown in Supplementary Table 2. For subjects’ information related to e, see Supplementary Table 1. Source data are provided as a Source data file.