Effects of Dimethyl Sulfoxide in Cholesterol-Containing Lipid Membranes: A Comparative Study of Experiments In Silico and with Cells

Abstract

Dimethyl sulfoxide (DMSO) has been known to enhance cell membrane permeability of drugs or DNA. Molecular dynamics (MD) simulations with single-component lipid bilayers predicted the existence of three regimes of action of DMSO: membrane loosening, pore formation and bilayer collapse. We show here that these modes of action are also reproduced in the presence of cholesterol in the bilayer, and we provide a description at the atomic detail of the DMSO-mediated process of pore formation in cholesterol-containing lipid membranes. We also successfully explore the applicability of DMSO to promote plasma membrane permeability to water, calcium ions (Ca2+) and Yo-Pro-1 iodide (Yo-Pro-1) in living cell membranes. The experimental results on cells in culture can be easily explained according to the three expected regimes: in the presence of low doses of DMSO, the membrane of the cells exhibits undulations but no permeability increase can be detected, while at intermediate DMSO concentrations cells are permeabilized to water and calcium but not to larger molecules as Yo-Pro-1. These two behaviors can be associated to the MD-predicted consequences of the effects of the DMSO at low and intermediate DMSO concentrations. At larger DMSO concentrations, permeabilization is larger, as even Yo-Pro-1 can enter the cells as predicted by the DMSO-induced membrane-destructuring effects described in the MD simulations.

Effects of Dimethyl Sulfoxide on Lipid Membrane Electroporation

“…1). When DMSO is added to the system, it accumulates in the interfacial membrane/water region, and due to its amphiphilic character and small size, it causes a lipid disordering effect 5 (lipid profiles are smoothed), and it also greatly enhances water insertion (Fig. 1).…”

“…2,3 Membrane pores can also be chemically induced by the use of particular membrane-fluidizing compounds such us dimethyl sulfoxide (DMSO, (CH 3 ) 2 SO), a small amphiphilic molecule that has been shown to enhance cell permeability through the formation of water pores. 4,5 Recently, molecular dynamics (MD) simulations have been used to elucidate the molecular mechanisms leading to pore formation in simple lipid bilayers by both the application of an external electric field [6][7][8][9][10] and the effects of DMSO. 5,[10][11][12] According to the simulations, the molecular mechanism of electroporation occurs in different stages.…”

“…4,5 Recently, molecular dynamics (MD) simulations have been used to elucidate the molecular mechanisms leading to pore formation in simple lipid bilayers by both the application of an external electric field [6][7][8][9][10] and the effects of DMSO. 5,[10][11][12] According to the simulations, the molecular mechanism of electroporation occurs in different stages. First, the disordering of the water molecules at the membrane interface due to the applied field eventually generates a water defect/intrusion that initiates pore formation.…”

“…9,17,18 MD simulations also show that in the absence of any applied electric field, DMSO triggers a similar chain of events by promoting water defects that initiate hydrophobic water columns that later develop into stable hydrophilic membrane pores. 5,[10][11][12] Because the physical (electroporation) and chemical (DMSO-induced) methods follow a similar sequence for pore formation, the combination of both acting simultaneously is expected to lead to pore formation under more favorable conditions. Actually, the increase of electroporation efficiency by DMSO has been experimentally observed.…”

Application of Low-Dose Laser Irradiation and 3D-Observation Methods for Detection and Assay of Features for Cell Differentiation Directions: A Pilot Study

“…10 Large numbers of osteoclasts could be derived from embryonic stem cells in the presence of appropriate growth factors and co-factors. Messages about enhanced cell differentiation to one or another direction on the influence of cryo-protector Dimethylsulfoxide (DMSO), 4,11,12 but also of other organic detergents, 13 have been obtained. Furthermore, the role of this substance in the activation of fusion process between the cells, has also been indicated 14,15 .…”