Protective Effect of Phillyrin on Lethal LPS-Induced Neutrophil Inflammation in Zebrafish

Abstract

Background/Aims: Forsythia suspensa Vahl. (Oleaceae) fruits are widely used in traditional Chinese medicine to treat pneumonia, typhoid, dysentery, ulcers and oedema. Antibacterial and anti-inflammatory activities have been reported for phillyrin (PHN), the main ingredient in Forsythia suspensa Vahl fruits, in vitro. However, the underlying mechanisms in vivo remain poorly defined. In this study, we discovered that PHN exerted potent anti-inflammatory effects in lethal LPS-induced neutrophil inflammation by suppressing the MyD88-dependent signalling pathway in zebrafish. Methods: LPS-yolk microinjection was used to induce a lethal LPS-infected zebrafish model. The effect of PHN on the survival of zebrafish challenged with lethal LPS was evaluated using survival analysis. The effect of PHN on neutrophil inflammation grading in vivo was assessed by tracking neutrophils with a transgenic line. The effects of PHN on neutrophil production and migration were analysed by SB⁺ cell counts during consecutive hours after modelling. Additionally, key cytokines and members of the MyD88 signalling pathway that are involved in inflammatory response were detected using quantitative RT-PCR. To assess gene expression changes during consecutive hours after modelling, the IL-1β, IL-6, TNF-α, MyD88, TRIF, ERK1/2, JNK, IκBa and NF-κB expression levels were measured. Results: PHN could protect zebrafish against a lethal LPS challenge in a dose-dependent manner, as indicated by decreased neutrophil infltration, reduced tissue necrosis and increased survival rates. Up-regulated IL-1β, IL-6 and TNF-α expression also showed the same tendencies of depression by PHN. Critically, PHN significantly inhibited the LPS-induced activation of MyD88, IκBa, and NF-κB but did not affect the expression of ERK1/2 MAPKs or JNK MAPKs in LPS-stimulated zebrafish. Additionally, PHN regulated the MyD88/IκBα/NF-κB signalling pathway by controlling IκBα, IL-1β, IL-6, and TNF-α expression. Conclusion: This study provides a rationale for the clinical application of PHN as an anti-inflammatory agent.

Deficiency of immunoglobulin E protects mice from experimental abdominal aortic aneurysms

“…In response to pro‐inflammatory stimuli, MAPK plays an essential role in neutrophil adhesion, migration, and activation . Therefore, we examined whether IgE also activated the MAPK signaling pathway as a mechanism to explain increased IL6 expression.…”

“…In response to pro-inflammatory stimuli, MAPK plays an essential role in neutrophil adhesion, migration, and activation. [40][41][42][43] Therefore, we examined whether IgE also activated the MAPK signaling pathway as a mechanism to explain increased IL6 expression. When bone-marrow-derived neutrophils from Apoe −/− mice were treated with IgE, we detected significant increase of IL6, as determined by immunoblot analysis.…”

Screening of Bufadienolides from Toad Venom Identifies Gammabufotalin as a Potential Anti-inflammatory Agent

“…LPS is a typical proinflammatory agent that can trigger an inflammatory response and consequently activate a series of signaling cascades. Our research group initiatively established a zebrafish inflammatory model by microinjecting LPS into the yolk [19], which has been widely used in the rapid screening of anti-inflammatory drugs in vivo [20][21][22]. In this study, the anti-inflammatory effects of 14 bufadienolides at nontoxic doses (1, 4, and 12: 50 µM; 2, 13, and 14: 10 µM; 3 and 6: 5 µM; 5 and 8: 1 µM; 7, 9, and 11: 0.5 µM; 10: 4 µM) were evaluated for the first time using an LPS-stimulated zebrafish inflammatory model.…”

Forsythia suspensa extract enhances performance via the improvement of nutrient digestibility, antioxidant status, anti-inflammatory function, and gut morphology in broilers

“…The main reason for the enhancement of ADG and ADFI was that phillyrin, forythialan A, phillygenin, and forsythoside A in FSE played an important role in enhancing the immune function and antioxidant capacity of broilers ( Wang et al., 2008 , Zhang et al., 2013 ). Yang et al. (2017) reported phillyrin in FSE increased immune response and inhibited the lipopolysaccharide (LPS)-induced inflammatory damage, which benefited the health status and performance of broilers.…”