Phosphorylated Hexa-Acyl Disaccharides Augment Host Resistance Against Common Nosocomial Pathogens.

Hernandez A, Luan L, Stothers CL, Patil NK, Fults JB, Fensterheim BA, Guo Y, Wang J, Sherwood ER, Bohannon JK
Crit Care Med. 2019 47 (11): e930-e938

PMID: 31567352 · PMCID: PMC6791756 · DOI:10.1097/CCM.0000000000003967

OBJECTIVES - To determine whether synthetic phosphorylated hexa-acyl disaccharides provide antimicrobial protection in clinically relevant models of bacterial infection.

DESIGN - Laboratory study.

SETTING - University laboratory.

SUBJECTS - BALB/c, C57BL/10J, and C57BL/10ScNJ mice.

INTERVENTIONS - Mice were treated with lactated Ringer's (vehicle) solution, monophosphoryl lipid A, or phosphorylated hexa-acyl disaccharides at 48 and 24 hours prior to intraperitoneal Pseudomonas aeruginosa or IV Staphylococcus aureus infection. Leukocyte recruitment, cytokine production, and bacterial clearance were measured 6 hours after P. aeruginosa infection. In the systemic S. aureus infection model, one group of mice was monitored for 14-day survival and another for S. aureus tissue burden at 3 days postinfection. Duration of action for 3-deacyl 6-Acyl phosphorylated hexa-acyl disaccharide was determined at 3, 10, and 14 days using a model of intraperitoneal P. aeruginosa infection. Effect of 3-deacyl 6-Acyl phosphorylated hexa-acyl disaccharide on in vivo leukocyte phagocytosis and respiratory burst was examined. Leukocyte recruitment, cytokine production, and bacterial clearance were measured after P. aeruginosa infection in wild-type and toll-like receptor 4 knockout mice treated with 3-deacyl 6-Acyl phosphorylated hexa-acyl disaccharide or vehicle to assess receptor specificity.

MEASUREMENTS AND MAIN RESULTS - During intraperitoneal P. aeruginosa infection, phosphorylated hexa-acyl disaccharides significantly attenuated infection-induced hypothermia, augmented leukocyte recruitment and bacterial clearance, and decreased cytokine production. At 3 days post S. aureus infection, bacterial burden in lungs, spleen, and kidneys was significantly decreased in mice treated with monophosphoryl lipid A or phosphorylated hexa-acyl disaccharides, which was associated with improved survival. Leukocyte phagocytosis and respiratory burst functions were enhanced after treatment with monophosphoryl lipid A or phosphorylated hexa-acyl disaccharides. A time course study showed that monophosphoryl lipid A- and 3-deacyl 6-Acyl phosphorylated hexa-acyl disaccharide-mediated protection against P. aeruginosa lasts for up to 10 days. Partial loss of augmented innate antimicrobial responses was observed in toll-like receptor 4 knockout mice treated with 3-deacyl 6-Acyl phosphorylated hexa-acyl disaccharide.

CONCLUSIONS - Phosphorylated hexa-acyl disaccharides significantly augment resistance against clinically relevant Gram-negative and Gram-positive infections via enhanced leukocyte recruitment, phagocytosis, and respiratory burst functions of innate leukocytes. Improved antimicrobial protection persists for up to 10 days and is partially mediated through toll-like receptor 4.

MeSH Terms (18)

Analysis of Variance Animals Blotting, Western Cross Infection Cytokines Disaccharides Disease Models, Animal Hexosaminidase A Male Mice Mice, Inbred BALB C Mice, Inbred C57BL Mice, Knockout Peritoneal Cavity Random Allocation Staphylococcal Infections Statistics, Nonparametric Survival Rate

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