A mechanistic explanation of the inhibitory role of the protein corona on liposomal gene expression

Biochim Biophys Acta Biomembr. 2020 Mar 1;1862(3):183159. doi: 10.1016/j.bbamem.2019.183159. Epub 2019 Dec 16.

Abstract

The past three decades have witnessed fast advances in the use of cationic liposome-DNA complexes (lipoplexes) for gene delivery applications. However, no lipoplex formulation has reached into the clinical practice so far. The primary drawback limiting clinical use of lipoplexes is the lack of mechanistic understanding of their low transfection efficiency (TE) in vivo. In physiological environments, lipoplexes are coated by a protein corona (PC) that mediates the interactions with the cell machinery. Here we show that the formation of PC can change the interactions of multicomponent (MC) lipoplexes with our cell model (i.e., HeLa). At the highest lipoplex concentration, the formation of PC can reduce the TE of MC lipoplexes from 60% to <5%. Combining dynamic light scattering and synchrotron small-angle X-ray scattering (SAXS), we clarify that the formation of PC modifies physical-chemical properties of MC lipoplexes so as to affect their TE. Moreover, we examined single transfection barriers by a combination of fluorescence-activated cell sorting, single-cell real-time fluorescence confocal microscopy, and synchrotron SAXS. We demonstrate that PC formation has the ability to modify the relative contribution of caveolae-mediated endocytosis and macropinocytosis in lipoplexes uptake, in favor of the latter, increasing accumulation of PC-decorated lipoplexes into degradative lysosomal compartments. Finally, we report evidences that PC reduces the structural stability of lipoplexes against solubilization by cellular lipids, likely favoring premature DNA release and cytosolic digestion by DNAase. These combined effects revealed here offer a comprehensive mechanistic explanation on the reason behind reduction in gene expression of MC lipoplexes.

Keywords: Cationic liposomes; Lipoplexes; Protein corona.; Transfection efficiency; Transfection mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biochemical Phenomena
  • CHO Cells
  • Cations / chemistry
  • Cricetulus
  • Cytosol / chemistry
  • DNA / chemistry
  • Endocytosis / physiology
  • Gene Expression Regulation / physiology*
  • HeLa Cells
  • Humans
  • Lipids / chemistry
  • Liposomes / chemistry*
  • Liposomes / metabolism
  • Protein Corona / chemistry
  • Protein Corona / metabolism*
  • Scattering, Small Angle
  • Synchrotrons
  • Transfection
  • X-Ray Diffraction / methods

Substances

  • Cations
  • Lipids
  • Liposomes
  • Protein Corona
  • DNA