Biochanin A protect against lipopolysaccharide-induced acute lung injury in mice by regulating TLR4/NF-κB and PPAR-γ pathway.

Acute lung injury (ALI) is a serious respiratory syndrome featured with uncontrolled inflammatory response. Biochanin A has been showed to possess and anti-inflammatory effect. This study intended to explore the suppression of biochanin A on lipopolysaccharide (LPS)-induced ALI in mice. Seven hours later LPS-induced ALI model established, the indexes including, pathological changes, MPO activity, wet/dry ratio, proinflammatory cytokines TNF-α, IL-1ß, and IL-6, production, as well as and TLR4/NF-κB and PPAR-γ signaling pathway expression were compared bwtween different groups. In addition, bronchoalveolar lavage fluid (BALF) was collected and the levels of total protein, inflammatory cells and TNF-α, IL-1ß, and IL-6 were detected. The results revealed that LPS lead to significantly lung pathological injury, and damage of lung vascular permeability showing by higher lung wet/dry ratio and total protein levels in the BALF when compared to the control group mice. However, these changes significantly reversed by biochanin A. Moreover, the levels of inflammatory cells in BALF, proinflammatory cytokines TNF-α, IL-1ß, and IL-6, in both lung and BALF were also dose-dependently reduced by biochanin A during ALI process. To investigate the anti-inflammatory mechanisms of biochanin A, we found that biochanin A significantly inhibited the activation of TLR4/NF-κB signaling pathway induced by LPS. Furthermore, the expression of PPAR-γ also markedly increased in the mice after treated with biochanin A. In conclusion, biochanin A alleviated LPS-induced ALI by inhibiting the inflammatory response, which was mediated via down-regulating the activation of TLR4/NF-κB signaling pathway and enhancing the expression of PPAR-γ.

The protective effect of hyperin on LPS-induced acute lung injury in mice.

Hyperin, a flavonoid compound found in natural plants, has been reported that it have anti-inflammatory properties. However, the protective effects and mechanisms of hyperin on acute lung injury have not been reported so far. This research was designed to investigate the protective effects of hyperin on lipopolysaccharide-induced acute lung injury (ALI) in mice. The mice were stimulated with LPS in the presence or absence of hyperin and the MPO activity, lung wet/dry ratio, inflammatory cells in BALF, and cytokines, as well as NF-κB expression were assessed in lung tissue. Results showed that hyperin significantly inhibited LPS-induced histological changes, inflammatory cell infiltration, MPO activity and lung wet/dry ratio. Additionally, hyperin distinctly reduced the production of TNF-α, IL-1ß and IL-6 and the activation of NF-κB signaling pathways in LPS-induced ALI in mice. In conclusion, hyperin is an effective suppressor of inflammation and may be a promising potential therapeutic reagent for ALI treatment.

High-level expression and purification of soluble recombinant FGF21 protein by SUMO fusion in Escherichia coli.

BACKGROUND: Fibroblast growth factor 21 (FGF21) is a promising drug candidate to combat metabolic diseases. However, high-level expression and purification of recombinant FGF21 (rFGF21) in Escherichia coli (E. coli) is difficult because rFGF21 forms inclusion bodies in the bacteria making it difficult to purify and obtain high concentrations of bioactive rFGF21. To overcome this problem, we fused the FGF21 with SUMO (Small ubiquitin-related modifier) by polymerase chain reaction (PCR), and expressed the fused gene in E. coli BL21(DE3). RESULTS: By inducing with IPTG, SUMO-FGF21 was expressed at a high level. Its concentration reached 30% of total protein, and exceeded 95% of all soluble proteins. The fused protein was purified by DEAE sepharose FF and Ni-NTA affinity chromatography. Once cleaved by the SUMO protease, the purity of rFGF21 by high performance liquid chromatography (HPLC) was shown to be higher than 96% with low endotoxin level (<1.0 EU/ml). The results of in vivo animal experiments showed that rFGF21 produced by using this method, could decrease the concentration of plasma glucose in diabetic rats by streptozotocin (STZ) injection. CONCLUSIONS: This study demonstrated that SUMO, when fused with FGF21, was able to promote its soluble expression of the latter in E. coli, making it more convenient to purify rFGF21 than previously. This may be a better method to produce rFGF21 for pharmaceutical research and development.