Fig. 1.
LPS-induced TLR4 activation attenuates β3AR-induced thermogenesis and prevents WAT browning. a–f C57BL/6 male mice received i.p. injections of either saline (control), CL, or LPS+CL as described in experimental procedures (n = 6–8). a Representative thermography captured by IR camera. b Mean surface body temperature recorded by IR camera. c Relative Tlr4 mRNA level in inguinal sWAT. d Body weight changes over the course of administering either CL or LPS+CL. e Representative microscopic images of H&E staining for sWAT (scale bar = 100 µm). f Relative gene expression analysis by qPCR of sWAT. g hASC exposed to BMP7-conditioned medium in the presence or absence of LPS (100 ng/ml before and during adipocyte differentiation), and followed by Bt2-cAMP (0.5mM) stimulation for 7 h before harvesting mRNA. g and h Cultures of primary human adipocytes differentiated from human adipose-derived stem cells (hASC) as explained in experimental procedures. g (top panel) Phase contrast images for adipocytes 10 days after differentiation (scale bar = 400 µm). Arrows indicate the time line for LPS and BMP7 addition and initiation of adipocyte differentiation by adding differentiation medium (DM) and adipocyte maintenance medium (AM). g (bottom panel) Relative gene expression analysis by qPCR. h hASC exposed to LPS (100 ng/ml) before and during differentiation, and followed by Bt2-cAMP (0.5 mM) stimulation for 7 h before harvesting mRNA. h (top panel) Phase contrast images for adipocytes 10 days after differentiation (scale bar = 400 µm). Arrows indicate the time line for LPS addition and initiation of adipocyte differentiation (DM) and maintenance (AM). h (bottom panel) Relative gene expression analysis by qPCR. All data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 by Student’s t test. Values not sharing a common letter differ significantly (P < 0.05) by one-way ANOVA. sWAT, subcutaneous white adipose tissue; CL, CL-316,243; LPS, lipopolysaccharides; BMP7, bone morphogenic protein; UCP1, uncoupling protein 1; PGC1α, peroxisome proliferator-activated receptor gamma coactivator 1-alpha; CIDEA, cell death-inducing DFFA-like effector A; TNF-α, tumor necrosis factor-alpha; IL-1β, interleukin-1 beta; MCP1, monocyte chemoattractant protein-1.