Fig. 2.
Distinct requirements for the SNS in development and recruitment of beige fat. (A) Immunostaining for tyrosine hydroxylase (TH) in iWAT of P28 Ntrk1f/+ThCre, Ntrk1f/f, and Ntrk1f/fThCre mice housed at 22 °C. (B) Higher-magnification images of TH immunostained iWAT of P28 C57BL/6J, Ntrk1f/f, and Ntrk1f/fThCre mice housed at 22 °C. (C and D) Immunostaining for UCP1 in iWAT of Ntrk1f/f (C) or Ntrk1f/fThCre (D) mice at various postnatal ages that were bred and housed at 22 °C. (E) Quantification of UCP1 in iWAT of C57BL/6J (same as in Fig. 1C), Ntrk1f/f and Ntrk1f/fThCre mice using Imaris. Data pooled from 1 to 4 litters per time point and genotype (n = 8–26 samples per group) and analyzed by Student’s t test. (F) Immunostaining for TH and UCP1 in iWAT of P7 Ntrk1f/+ThCre and Ntrk1f/fThCre mice housed at 22 °C. (G and H) Heatmaps of down-regulated genes in the “Cholesterol biosynthetic process” (G) and “Lipid metabolic process” (H) GO categories in iWAT of P28 Ntrk1f/fThCre mice housed at 22 °C (n = 4 per genotype). (I) Immunostaining for TH in iWAT of 8- to 10-wk-old Ntrk1f/+ThCre, Ntrk1f/f, and Ntrk1f/fThCre mice housed at 22 °C. (J) Immunostaining for UCP1 in iWAT of 14- to 15-wk-old C57BL/6J, Ntrk1f/f, and Ntrk1f/fThCre mice housed at 10 °C for 11 d. (K) Immunostaining for UCP1 in iWAT of 10- to 11-wk-old Ntrk1f/+ThCre, Ntrk1f/f, and Ntrk1f/fThCre mice treated daily with vehicle or CL-316,243 (1 mg/kg intraperitoneally) for 7 d at 22 °C. The mesh-like structures in the Veh-22 °C- Ntrk1f/f image are autofluorescent mammary ducts. Data are presented as mean ± SEM. (Scale bars: A, C, D, and I–K, 1 mm; B, 200 μm; F, 500 μm.)