Fig. 1: iLN promotes cold-induced beiging of scWAT.

Eight-week-old male C57BL/6 N mice were housed at thermoneutral environment (30 °C) for 3 weeks and then subjected to exposure at 6 °C or 30 °C for 2 days. a In situ orientation of posterior scWAT (white dashed lines). iLN (black arrow); dorsolumbar, inguinal and gluteal regions (two-headed white arrows). b, c The mRNA (b) (n = 5) and protein (c) (n = 3) expressions of UCP1 in different regions of scWAT. d Representative images of different regions of scWAT stained with H&E (left) and immunohistochemical (IHC) staining for UCP1 (right). Scale bar, 200 μm. e–j Mice were subjected to bilateral inguinal lymphadenectomy (iLNX) or sham operation, and then housed at different temperatures as described above. e Macroscopic appearance of scWAT with (red-dotted circle) or without embedded-iLN (green-dotted circle) in sham-operated and iLNX mice. f Representative infrared images of sham-operated and iLNX mice housed at 30 °C or 6 °C. Quantification of the average surface temperature in the posterior subcutaneous (white-dotted circles) and interscapular regions (yellow-dotted circle) (right) (n = 4). g, h The mRNA level of thermogenic genes (g) (n = 5) and UCP1 protein expression (h) (n = 3) in scWAT. The right panel in (h) is the densitometric analysis for the relative abundance of UCP1 normalized with HSP90. i Representative images of H&E (left) and IHC staining for UCP1 (right) in scWAT. Scale bar, 200 μm. j Basal oxygen consumption rate (OCR) in the explants of scWAT (n = 5). All samples are biologically independent replicates. Data are presented as mean ± SEM. Statistical data were assessed using Mann–Whitney U test (b, f, g, j) or unpaired two-tailed Student’s t test (h). All the p values were two-sided. Source data are available as a Source Data file. kDa, relative molecular weight in kilodalton. See also Fig. S1–S2.