Invasin-functionalized liposome nanocarriers improve the intracellular delivery of anti-infective drugs

Abstract

Intracellular infections caused by invasive pathogens continue to prove difficult to combat, due in part to the commonly poor membrane permeability of anti-infective drugs. The aim of this study was to improve the intracellular delivery of one such poorly permeable (but broad-spectrum) anti-infective, gentamicin. Gentamicin was encapsulated into liposomal nanocarriers which were then surface functionalized with InvA497, a bacteria-derived invasion protein. Treatment of HEp-2 cells infected with the enteroinvasive bacteria Yersinia pseudotuberculosis or Salmonella enterica with gentamicincontaining, InvA497-functionalized liposomes resulted in a significantly greater reduction in infection load than treatment with non-functionalized liposomes, indicating that such a bacteriomimetic nanocarrier was not only able to promote successful cellular uptake of gentamicin but was also able to mediate anti-infective drug delivery to both cell cytoplasm and intracellular compartments. The developed InvA497-functionalized liposomal nanocarrier therefore holds great promise as a strategy for improving the therapy of intracellular infections.

Aspherical and Spherical InvA497-Functionalized Nanocarriers for Intracellular Delivery of Anti-Infective Agents

“…Nanoparticle formulations were then incubated with HEp-2 cells to determine the cellular uptake. A previous study conducted with liposomal nanoparticles functionalized with the same InvA497 invasin fragment has shown an increased cellular uptake due to the presence of InvA497 on the surface of such nanocarriers ( 3 , 9 ); in accordance with this observation, InvA497 functionalization of both spherical and aspherical nanoparticles in the current work enhanced their uptake and internalization into epithelial cells, as confirmed by both CLSM (Fig. 3 ) and FACS analysis (Fig.…”

“…Aspherical and spherical nanoparticles were then surface-functionalized with InvA497, a C- terminal fragment of the Yersinia-derived invasion protein invasin. As observed previously ( 3 , 5 , 9 ), the uptake of spherical delivery systems functionalized with InvA497 is enhanced due to the presence of this bacterial protein on particle surfaces; it was therefore of interest to see whether the same effect was noted with an aspherical delivery system. In order to bind to the β 1 integrin receptor on epithelial cells and mediate internalization, the C- terminal carboxyl group of InvA497 must remain free and project outwards from the particle surface.…”

“…Before carrying out uptake studies, the cytotoxicity of AsphI, SphI, Asph and Sph in a HEp-2 epithelial cell model was preliminarily assessed at values encompassing a feasible working range. Nanoparticle concentrations resulting in a comparable InvA497 concentration to that of the previously tested InvA497-functionalized liposomes ( 9 ), and corresponding to the maximum possible concentration of dose-able InvA497 were used (Fig. S2 ).…”

“…Dersch et al . were able to produce and purify such a C- terminal, cell-invasive fragment of invasin, referred to as InvA497 ( 8 ); gentamicin-loaded liposomes surface functionalized with InvA497 were further demonstrated to be able to reach and kill intracellular bacteria located in various epithelial sub-cellular compartments ( 3 , 9 ).…”

Biogenic and Biomimetic Carriers as Versatile Transporters To Treat Infections

“…26 In a follow-up study, Menina and collaborators showed that the invasin-functionalized liposomes loaded with the model antibiotic gentamycin had a greater antimicrobial effect on intracellular Y. pseudotuberculosis and Salmonella enterica in HEp-2 epithelial cells when compared to non-functionalized liposomes, due to their surface modification. 27 This approach indicates that taking advantage of the natural bacterial invasion characteristics may aid in enhancing the antibacterial activity of drugs that have poor permeability, such as gentamycin.…”