Application of the Phage Lysin Ply5218 in the Treatment of Streptococcus suis Infection in Piglets.

Streptococcus suis (S. suis) is a gram-positive bacterium and zoonotic pathogen. Currently it poses a serious problem in the swine industry due to the emergence of antibiotic-resistant bacteria. Thus, novel antimicrobials against S. suis infections are urgently needed. In the previous study, a cell wall hydrolase or lysin derived from Streptococcus prophage phi5218, termed Ply5218, was identified. This lysin showed strong bacteriolytic activity against S. suis. In the current study, the in vitro data showed that after incubation with pig serum, the bacteriolytic efficacy of Ply5218 declined in a time-dependent manner. The in vivo assays indicated that a Ply5218 triple treatment (6, 24, and 48 h post infection) was effective against various serotypes of S. suis in a murine infection model. This regimen also alleviated streptococcal-induced clinical symptoms in piglets and significantly reduced the bacterial burden and levels of interleukin 6, a proinflammatory cytokine. This study indicates that Ply5218 shows strong antibacterial activity in pigs and has the potential to be used as a treatment for infectious diseases caused by S. suis.

Juglone prevents metabolic endotoxemia-induced hepatitis and neuroinflammation via suppressing TLR4/NF-κB signaling pathway in high-fat diet rats.

Juglone as a natural production mainly extracted from green walnut husks of Juglans mandshurica has been defined as the functional composition among a series of compounds. It showed powerful protective effect in various diseases by inhibiting inflammation and tumor cells growth. However, studies on its anti-inflammatory effect based on high-fat diet-induced hepatitis and neuroinflammation are still not available. In this regard, we first investigated whether juglone suppresses high-fat diet-stimulated liver injury, hypothalamus inflammation and underlying mechanisms by which they may recover them. SD rats were orally treated with or without high-fat diet, 0.25 mg/kg or 1 mg/kg juglone for 70 days. Subsequently, blood, hypothalamus and liver tissue were collected for different analysis. Also, the primary astrocytes were isolated and used to analyze the inhibitory effect of juglone in vitro. Analysis of inflammatory cytokines declared that the inhibition of TNF-α, IL-1ß and IL-6 could be carried by juglone in response to high-fat diet rats. Meanwhile, TLR4 expression and NF-kappa activity also have been confirmed to be the key link in the development of hepatitis and nerve inflammation. The activation was significantly suppressed in treatment group as compared with model. These results indicated that juglone prevents high-fat diet-induced liver injury and nerve inflammation in mice through inhibition of inflammatory cytokine secretion, NF-kappa B activation and endotoxin production.