Fig. 4.

Improvement effect of Notch1 deficiency in macrophages on hepatic steatosis and insulin resistance is mainly dependent on the increase in Treg frequency.

Notch1^FL/FL mice and Notch1^M-KO mice were fed a NCD or HFD for 6 weeks. (A) Proportion of hepatic CD25⁺Foxp3⁺ Tregs gated on CD3⁺CD4⁺ T cells was analyzed by flow cytometry in Notch1^FL/FL mice and Notch1^M-KO mice (six/group). (B) Foxp3 mRNA expression in the liver of Notch1^FL/FL mice and Notch1^M-KO mice (six/group). Notch1^FL/FL mice, Notch1^M-KO mice, and Notch1^M-KO mice with Tregs eliminated (injected intraperitoneally with anti-CD25 antibodies) were fed a HFD for 6 weeks. The body weight (C), GTT, ITT (D), serum TG, TC, LDL-C, and HDL-C levels (E), and liver TG and TC levels (F) were measured (five/group). (G) Representative images of H&E and Oil red O staining of liver sections (scale bar: 100 μm). (H) Western blot analyses of insulin-stimulated expression of Akt and pAkt in the liver (three/group). (I) The level of IL-10 in the liver was measured by ELISA (five/group). Values represent means ± SD. Statistical analysis was performed by one-way ANOVA and Tukey's test. ∗p <0.05, ∗∗p <0.01, ∗∗∗p <0.001. Abbreviations: GTT, glucose tolerance test; HDL-C, HDL cholesterol; HFD, high-fat diet; ITT, insulin tolerance test; LDL-C, LDL cholesterol; NCD, normal chow diet; Notch1^FL/FL, floxed Notch1; Notch1^M-KO, myeloid-specific Notch1-knockout; TC, total cholesterol; TG, triglyceride; Treg, regulatory T cell.