Interactions of the lysosomotropic detergent omethyl-serine dodecylamide hydrochloride (Msdh) with lipid bilayer membranes-implications for cell toxicity

• O-methyl-serine dodecylamine hydrochloride (MSDH) is a detergent that accumulates selectively in lysosomes, a so-called lysosomotropic detergent, with unexpected chemical properties. At physiological pH, it spontaneously forms vesicles, which disassemble into small aggregates (probably micelles) below pH 6.4. In this study, we characterize the interaction between MSDH and liposomes at different pH and correlate the findings to toxicity in human fibroblasts. We find that the effect of MSDH on lipid membranes is highly pH-dependent. At neutral pH, the partitioning of MSDH into the liposome membrane is immediate and causes the leakage of small fluorophores, unless the ratio between MSDH and lipids is kept low. At pH 5, the partitioning of MSDH into the membrane is kinetically impeded since MSDH is charged and a high ratio between MSDH and the lipids is required to permeabilize the membrane. When transferred to cell culture conditions, the ratio between MSDH and plasma membrane lipids must therefore be low, at physiological pH, to maintain plasma membrane integrity. Transmission electron microscopy suggests that MSDH vesicles are taken up by endocytosis. As the pH of the endosomal compartment progressively drops, MSDH vesicles disassemble, leading to a high concentration of increasingly charged MSDH in small aggregates inside the lysosomes. At sufficiently high MSDH concentrations, the lysosome is permeabilized, the proteolytic content released to the cytosol and apoptotic cell death is induced.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biofysik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biophysics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

Liposome

Lysosomal membrane permeabilization

Lysosome

Lysosomotropic detergent

MSDH

caspase 3

detergent

lactate dehydrogenase

methyl serine dodecylamide hydrochloride

n acetyl beta glucosaminidase

unclassified drug

AG1518 cell line

apoptosis

Article

cell damage

cell permeabilization

cell viability

confocal laser scanning microscopy

controlled study

cytotoxicity

cytotoxicity assay

endocytosis

enzyme activity

fibroblast cell line

fluorescence correlation spectroscopy

human

human cell

immunocytochemistry

incubation time

lipid bilayer

live cell imaging

molecular interaction

molecular stability

MTT assay

pH

photon correlation spectroscopy

spectrofluorometry

transmission electron microscopy

Western blotting

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)