Liposomes loaded with bioactive lipids enhance antibacterial innate immunity irrespective of drug resistance

Sci Rep. 2017 Mar 27:7:45120. doi: 10.1038/srep45120.

Abstract

Phagocytosis is a key mechanism of innate immunity, and promotion of phagosome maturation may represent a therapeutic target to enhance antibacterial host response. Phagosome maturation is favored by the timely and coordinated intervention of lipids and may be altered in infections. Here we used apoptotic body-like liposomes (ABL) to selectively deliver bioactive lipids to innate cells, and then tested their function in models of pathogen-inhibited and host-impaired phagosome maturation. Stimulation of macrophages with ABLs carrying phosphatidic acid (PA), phosphatidylinositol 3-phosphate (PI3P) or PI5P increased intracellular killing of BCG, by inducing phagosome acidification and ROS generation. Moreover, ABLs carrying PA or PI5P enhanced ROS-mediated intracellular killing of Pseudomonas aeruginosa, in macrophages expressing a pharmacologically-inhibited or a naturally-mutated cystic fibrosis transmembrane conductance regulator. Finally, we show that bronchoalveolar lavage cells from patients with drug-resistant pulmonary infections increased significantly their capacity to kill in vivo acquired bacterial pathogens when ex vivo stimulated with PA- or PI5P-loaded ABLs. Altogether, these results provide the proof of concept of the efficacy of bioactive lipids delivered by ABL to enhance phagosome maturation dependent antimicrobial response, as an additional host-directed strategy aimed at the control of chronic, recurrent or drug-resistant infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cell Line, Tumor
  • Cells, Cultured
  • Child
  • Drug Resistance, Bacterial
  • Female
  • Humans
  • Immunity, Innate*
  • Liposomes*
  • Macrophages / drug effects
  • Macrophages / immunology
  • Male
  • Phagocytosis*
  • Phagosomes / drug effects
  • Phagosomes / immunology
  • Phosphatidylinositol Phosphates / administration & dosage
  • Phosphatidylinositol Phosphates / immunology*
  • Phosphatidylinositol Phosphates / pharmacology
  • Pseudomonas aeruginosa / immunology

Substances

  • Liposomes
  • Phosphatidylinositol Phosphates