We observed that anatabine inhibits basal STAT3 phosphorylation levels (Mann– Whitney U=0, Z=-2.882, P=0.004) and reduces the induction of p65 NFkB phosphorylation by TNFa (Mann–Whitney U=0, Z=-2.882, P=0.004) within this 15 min time-frame (Fig. 1)
Under these culture conditions, anatabine also inhibited both STAT3 and p65 NFkB phosphorylation induced by TNFa (Fig. 2)
A significant inhibition of STAT3 phosphorylation was observed with 600 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021) and with 800 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021) and a significant inhibition of p65 NFkB phosphorylation was observed with 600 mg/ml of anatabine (Mann–Whitney U=1.0, Z=-2.021, P=0.043) and with 800 mg/ml of anatabine (Mann–Whitney U=0,Z=-2.309, P=0.021)
We observed that anatabine significantly suppressed the stimulation of p65 NFkB and STAT3 phosphorylation by LPS in microglia (Fig. 3)
Kruskal–Wallis test revealed that doses of anatabine significantly suppressed both LPS induced STAT3 phosphorylation (H=15.658, df=4, P=0.005) and p65 NFkB phosphorylation (H=14.150, df=4, P=0.007) in human microglia
A significant inhibition of STAT3 phosphorylation was observed with 10 mg/ml of anatabine (Mann–Whitney U=1, Z=-2.021, P=0.043), with 100 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021), with 300 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021) and with 600 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021)
An inhibition of TNFa induced STAT3 (Mann–Whitney U=0, Z=-2.121, P=0.034), and p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-2.121, P=0.034) was observed in these cells following the anatabine treatment (Fig. 4) suggesting that anatabine may also mediate its anti-inflammatory activity independently of nicotinic acetylcholine receptor expression
Anatabine appears to completely antagonize LPS induced STAT3 (Mann–Whitney U=0, Z=-3.077, P=0.002) and p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-3.077, P=0.002) in human mononuclear cells
Similarly, LPS induced p65 NFkB phosphorylation in microglia was significantly inhibited with 10 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021), with 100 mg/ml of anatabine (Mann– Whitney U=0, Z=-2.309, P=0.021), with 300 mg/ml of anatabine (Mann–Whitney U=0, Z=-2.309, P=0.021)
Western-blot experiments revealed that LPS significantly stimulated of STAT3 phosphorylation in the spleen (Mann–Whitney U=0, Z=-2.309, P=0.021) (Fig. 8) and kidney (Mann–Whitney U=0, Z=-2.882, P=0.004) (data not shown) whereas anatabine significantly inhibited STAT3 phosphorylation in the spleen (Mann–Whitney U=1, Z=-2.021, P=0.043) and kidney (Mann– Whitney U=5, Z=-2.082, P=0.037) (data not shown)
A significant elevation of STAT3 phosphorylation was detected in the brain of Tg APPsw compared to their control littermates (Mann–Whitney U=1, Z=-3.767, p<0.001) and a significant reduction in STAT3 phosphorylation (Mann–Whitney U=8, Z=-2.066, p=0.039) was observed in the brain of Tg APPsw treated with anatabine compared to untreated Tg APPsw littermates (Fig. 10).
Following 90 days of treatment with anatabine, a significant reduction in brain TNF-a (Mann–Whitney U=6, Z=-2.146, p=0.032) and in IL-6 (Mann–Whitney U=0, Z=-2.887, p=0.004) was observed in Tg APPsw mice compared to Tg APPsw that received regular drinking water (Fig. 9)
An increased STAT3 (Mann–Whitney U=0, Z=-2.309, P=0.021) and p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-2.309, p=0.021) was observed in LPS treated microglia (Fig. 3)
Following a 24 h incubation with LPS, a significant stimulation of STAT3 (Mann– Whitney U=0, Z=-2.882, P=0.004) and p65 NFkB phosphorylation was observed (Mann–Whitney U=1, Z=-2.722, P=0.006)
Anatabine at 200 mg/ ml significantly lowered LPS induced IL-1b levels in whole blood (Mann–Whitney U=0.0, Z=-2.3, P=0.02)
Our results showed that intraperitoneal injection of LPS (1 mg/kg) caused a significant elevation of plasma IL-1b (Mann–Whitney U=3, Z=-2.988, P=0.003), IL-6 (Mann–Whitney U=0, Z=-3.366, P=0.001) and TNFa (Mann– Whitney U=0, Z=-3.508, P<0.001) 4 h after the LPS challenge whereas in mice co-treated with an intraperitoneal injection of anatabine (2 mg/kg) and LPS, a significant reduction in plasma IL-1b (Mann–Whitney U=7, Z=-2.645, P=0.008) and TNFa (Mann–Whitney U=4, Z=-2.941, P=0.003) levels was observed (Fig. 6)
An elevation of IL-6 (Mann–Whitney U=0, Z=-3.487, P<0.001), IL1b (Mann– Whitney U=0, Z=-3.24, P=0.001) and TNFa (Mann–Whitney U=0, Z=-3.361, P=0.001) was observed in the spleen of LPS challenged mice (Fig. 7)
Similarly, IL-1b (Mann–Whitney U=0, Z=-3.098, P=0.002), IL-6 (Mann–Whitney U=0, Z=-3.363, P<0.001) and TNF-a levels (Mann–Whitney U=0, Z=-3.361, P=0.001) were elevated in the kidney following the LPS challenge (data not shown)
Nicotine has been shown to modulate inflammation by affecting STAT3 phosphorylation (Chatterjee et al., 2009; Hosur and Loring, 2011) and by opposing NFkB activation (Leite et al., 2010; Zhou et al., 2010)
As a positive control, we used stattic, a known inhibitor of STAT3 dimerization and phosphorylation
We found that stattic inhibited STAT3 phosphorylation (Mann–Whitney U=0, Z=-2.324, P=0.02) and also suppressed p65 NFkB phosphorylation (Mann–Whitney U¼0, Z¼2.324, P¼0.02) mimicking the effect of anatabine in SHSY5Y cells (Fig. 1)
We next tested the impact of anatabine on STAT3 and p65 NFkB phosphorylation induced by a 24 h treatment with LPS on human microglial cells, a cell type known to express alpha7-nicotinic acetylcholine receptor subtype (Suzuki et al., 2006)
Anatabine significantly inhibited LPS induced IL-6 (Mann–Whitney U=4, Z=-3.303, P=0.001), TNF-a (Mann–Whitney U=0, Z=-3.361, P=0.001) and IL-1b levels in the spleen (Mann–Whitney U=9, Z=-1.981, P=0.048) (Fig. 7)
A significant reduction in TNF-a (Mann–Whitney U=12, Z=-2.309, P=0.021) but no significant reduction in IL-6 levels (Mann–Whitney U=25, Z=-1.223, P=0.221) or IL-1b (Mann–Whitney U=8, Z=-1.857,P=0.063) were observed in the kidney of LPS and anatabine cotreated animals (data not shown)
Plasma IL-6 levels show a trend for a reduction but were not significantly affected (Mann–Whitney U=19, Z=-1.368, P=0.171) by the anatabine treatment (Fig. 6)
Higher doses of anatabine resulted in a complete suppression of IL-1b levels in LPS challenged human blood (Mann–Whitney U=0.0, Z=-2.5, P=0.01)
Following this 15 mins of stimulation with TNFa, an increased p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-2.309, P=0.021) without a noticeable increase in STAT3 phosphorylation (Mann–Whitney U=7, Z=-0.289, P=0.773) was observed compared to the control conditions (Fig. 1)
An increased in both STAT3 (Mann–Whitney U=0, Z=-2.309, P=0.021) and p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-2.309, P=0.021) was observed following 24 h of treatment with TNFa
TNFa significantly stimulated STAT3 (Mann–Whitney U=0, Z=-2.309, P=0.021) and p65 NFkB phosphorylation (Mann–Whitney U=0, Z=-2.309, P=0.021)
An elevation of brain IL-6 (Mann–Whitney U=0, Z=-3, p=0.003) and TNF-a (Mann–Whitney U=0, Z=-2.887, p=0.004) was observed in Tg APPsw mice compared to their wild-type littermates (Fig. 9)
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If you find BEL Commons useful in your work, please consider citing: Hoyt, C. T., Domingo-Fernández, D., & Hofmann-Apitius, M. (2018). BEL Commons: an environment for exploration and analysis of networks encoded in Biological Expression Language. Database, 2018(3), 1–11.