Outer Membrane Vesicles Displaying a Heterologous PcrV-HitA Fusion Antigen Promote Protection against Pulmonary Pseudomonas aeruginosa Infection.

Along with surging threats and antibiotic resistance of Pseudomonas aeruginosa in health care settings, it is imperative to develop effective vaccines against P. aeruginosa infection. In this study, we used an Asd (aspartate-semialdehyde dehydrogenase)-based balanced-lethal host-vector system of a recombinant Yersinia pseudotuberculosis mutant to produce self-adjuvanting outer membrane vesicles (OMVs). The OMVs were used as a carrier to deliver the heterologous PcrV-HitAT (PH) fusion antigen of P. aeruginosa for vaccine evaluation. Intramuscular vaccination with OMVs carrying the PH antigen (referred to rOMV-PH) afforded 73% protection against intranasal challenge with 5 × 106 (25 50% lethal doses) of the cytotoxic PA103 strain and complete protection against a noncytotoxic PAO1 strain. In contrast, vaccination with the PH-deficient OMVs or PH antigen alone failed to offer effective protection against the same challenge. Immune analysis showed that the rOMV-PH vaccination induced potent humoral and Th1/Th17 responses compared to the PH vaccination. The rOMV-PH vaccination rapidly cleared P. aeruginosa burdens with coordinated production of proinflammatory cytokines in mice. Moreover, antigen-specific CD4+ and CD8+ T cells and their producing cytokines (tumor necrosis factor alpha and interleukin-17A), rather than antibodies, were essential for protection against pneumonic P. aeruginosa infection. Our studies demonstrated that the recombinant Y. pseudotuberculosis OMVs delivering heterologous P. aeruginosa antigens could be a new promising vaccine candidate for preventing the spread of drug-resistant P. aeruginosa. IMPORTANCE Hospital- and community-acquired infections with Pseudomonas aeruginosa cause a high rate of morbidity and mortality in patients who have underlying medical conditions. The spread of multidrug-resistant P. aeruginosa strains is becoming a great challenge for treatment using antibiotics. Thus, a vaccine as one of the alternative strategies is urgently required to prevent P. aeruginosa infection.

Effect of Andrographolide on Gene Expression Profile and Intracellular Calcium in Primary Rat Myocardium Microvascular Endothelial Cells.

Andrographolide (ANDRO) is a diterpene lactone compound with extensive biological effects, such as antibacterial, antitumor and treatment of cardiovascular diseases. Until now, studies on the pharmacological functions of ANDRO are still in progress. However, little is known about the gene expression profile and calcium response of endothelial cells to ANDRO. In this study, we used a microarray technology to investigate the gene expression responses in primary rat myocardium microvascular endothelial cells treated with 10 µg/mL ANDRO. The expression of caveolin-1 and 1-phosphatidylinositol 4, 5-bisphosphate phosphodiesterase δ3 was verified by RT-PCR and western blot. In addition, we investigated the effect of ANDRO on intracellular calcium induced by exogenous adenosine triphosphate and on inflammatory response induced by lipopolysaccharide. Results showed that ANDRO treatment induced an abundance of differential expressed genes, exhibiting a multitarget regulatory effect. ANDRO significantly decreased caveolin-1 and phosphodiesterase δ3 expression, lipopolysaccharide-induced IL-6 and TNF-α levels and expression of several chemokine genes, which are associated with reducing inflammation response and decreasing calcium release without affecting normal endothelia cell function, suggesting that ANDRO may be a potential candidate to treat cardiovascular diseases with less toxicity.