TLR4 links innate immunity and fatty acid–induced insulin resistance
J. Clin. Invest. Hang Shi, et al. 116:3015 doi:10.1172/JCI28898 [
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Figure 4FFAs cause inflammatory response via TLR4 in adipocytes. (
A–
C) Generation of an adipocyte model with specific TLR4 knockdown. 3T3-L1 preadipocytes were infected with retroviral short hairpin RNA interference (shRNAi) to knock down TLR4 (TLR4-KD), and cells were selected and then differentiated into adipocytes. TLR4 mRNA (
A) and protein (
B) and TLR2 mRNA (
C) levels were evaluated by real-time RT-PCR and immunoblotting. Data are expressed as mean ± SEM;
n = 6; *
P < 0.05. (
D and
E) FFAs stimulate IL-6 and TNF-α mRNA expression in 3T3-L1 adipocytes via TLR4. TLR4-knockdown and scramble control adipocytes were treated with 400 μM FFA (palmitate and oleate mixture) or 100 ng/ml LPS for 12 hours. Real-time RT-PCR was conducted to measure the mRNA levels.
n = 4; *
P < 0.05. (
F and
G) FFAs stimulate TNF-α and IL-6 mRNA in WT but not in
TLR4–/– adipocytes (
n = 4; *
P < 0.05). (
H and
I) FFAs stimulate TNF-α and IL-6 protein secretion in WT but not in
TLR4–/– adipocytes (
n = 4; *
P < 0.05). Mouse adipocytes were isolated and precultured for 6 hours and then were treated with 400 μM FFA mixture for 16 hours. Real-time RT-PCR was used to measure mRNA levels. Data are expressed as mean ± SEM.
