Fig. 4: miR-33b^+/+ mice show increased BAT activity with higher sympathetic nerve activity.

a Core body temperature of miR-33b^−/− and miR-33b^+/+ male mice kept at room temperature. n = 24, 25 mice per group, ***p < 0.001, two-sided unpaired t test. b Core body temperature of miR-33b^−/− and miR-33b^+/+ female mice kept at room temperature. n = 32, 31 mice per group, ***p < 0.001, two-sided unpaired t test. c Representative images of HE staining for the BAT of miR-33b^−/− and miR-33b^+/+ mice kept at room temperature. n = 6 mice per group. Scale bar, 100 μm (upper), 200 μm (lower). d Quantitative real-time PCR analysis of Ucp1, Adrb3, and Ppargc1a in the BAT of miR-33b^−/− and miR-33b^+/+ mice kept at room temperature. n = 8, 9 mice per group, **p < 0.01, *p < 0.05, two-sided unpaired t test. e Western blotting analysis of ABCA1, UCP1, TH, and GAPDH in the BAT of miR-33b^−/− and miR-33b^+/+ mice kept at room temperature. n = 5 mice per group. The arrow indicates specific bands of TH staining. f Densitometry for UCP1 and TH in the BAT of miR-33b^−/− and miR-33b^+/+ mice at room temperature. n = 5 mice per group, *p < 0.05, two-sided unpaired test. g Representative images of immunohistochemistry for TH in the BAT of miR-33b^−/− and miR-33b^+/+ mice at room temperature. n = 3 mice per group. Scale bar, 100 μm. h Oxygen consumption rate of miR-33b^−/− and miR-33b^+/+ mice kept at 23 °C. n = 10 mice per group, p < 0.05, fdANOVA. i Mean oxygen consumption rate during the light and dark phase in miR-33b^−/− and miR-33b^+/+ mice kept at 23 °C. n = 10 mice per group, ***p < 0.001, two-sided unpaired t test. j Maximum oxygen consumption by 1.0 mg/kg subcutaneous norepinephrine (NE) injection. miR-33b^−/− and miR-33b^+/+ mice kept at room temperature were used. Measurement was performed at 30 °C in a chamber. n = 15, 14 mice per group, *p < 0.05, Mann–Whitney test for each time. k Norepinephrine contents in BAT of miR-33b^−/− and miR-33b^+/+ mice before and after AMPT injection. n = 6–8 mice per group, *p < 0.05, two-way ANOVA with Bonferroni’s post hoc test. l Representative images of c-fos immunohistochemistry of the rRPa of miR-33b^−/− and miR-33b^+/+ mice kept at room temperature. n = 8, 9 mice per group. Scale bar, 200 μm (upper). m Number of c-fos positive cells at the rRPa of miR-33b^−/− and miR-33b^+/+ mice kept at room temperature. n = 8, 9 mice per group, *p < 0.05, two-sided unpaired t test. All data are presented as mean ± SEM.