Figure 4. Knockdown of Fst improves WAT insulin sensitivity, reduces HGP and improves glucose tolerance in LDKO mice.

Panels a–g: Two to three-month old LDKO mice were infected with ‘null^AAV•TBG’ (encoding luciferase) or with sgFst^AAV•TBG (encoding small guide RNA sgFst1 or sgFst2) to effect partial hepatic Fst knockout (n = 7). (a,b) Hepatic Fst protein content (a) and serum total Fst concentration (b) were measured two weeks after infection. (c) GTTs were performed 10 days after infection and summarized by the areas under curves (AUC). (d) Fasting serum insulin levels were measured two weeks after infection. (e) Insulin-stimulated Irs1•p110^PI3K complex formation in eWAT, measured two weeks after infection. (f,g) Insulin regulated phosphorylation of Akt and HSL in eWAT was analyzed two weeks after infection by Western blotting (f) and quantitated by densitometry (g). Panels h–k: Five-month old LDKO mice were infected with ‘null^AAV•TBG’ or shFst^AAV•TBG (encoding a miRNA-like hairpin RNA against Fst) and hyperinsulinemic-euglycemic clamps were conducted four weeks later (n = 5). (h and i) Blood glucose concentrations (h) and glucose infusion rates (i) before and at steady-state during hyperinsulinemic-euglycemic clamp. (j,k) Basal and clamped hepatic glucose production (j) and calculated suppression of HGP by insulin during the clamp (k). Panels l–n: Five weeks of C57BL6 mice maintained on high fat diet for two months were infected with shFst^AAV-TBG or Null^AAV-TBG (n = 7). Serum Fst levels were measured two weeks after infection (l); GTTs (m) and fasting blood glucose levels (n) were measured ten days after infection. Data (b,d,e) were reported as the median±95%CI, and Kruskal-Wallis test was used to identify significant differences between treatments of LDKO mice. Other data were reported as the mean±SEM. Data were analyzed by One-way ANOVA (a,c,g,j), two-way ANOVA (i) and unpaired Student’s t-test (k,l,m,n). P<0.05; **P<0.01; ***P<0.001; ****P<0.0001.