Calorimetric and molecular mechanics studies of the thermotropic phase behavior of membrane phospholipids

Huang, Chunbo; Li, Shusen

doi:10.1016/s0005-2736(99)00099-1

Cited by 188 publications

(127 citation statements)

References 68 publications

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“…All experiments were carried out in triplicate. The pretransition and main phase transitions of DPPC are in good agreement with literature data [13,16].…”

Section: Differential Scanning Calorimetrysupporting

confidence: 90%

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Lehmler

Xie

Bothun

et al. 2006

Colloids and Surfaces B: Biointerfaces

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Perfluorooctane-1-sulfonic acid (PFOS) is emerging as an important persistent environmental pollutant. To gain insight into the interaction of PFOS with biological systems, the mixing behavior of dipalmitoylphosphatidylcholine (DPPC) with PFOS was studied using differential scanning calorimetry (DSC) and fluorescence anisotropy measurements. In the DSC experiments the onset temperature of the DPPC pretransition (T p ) decreased with increasing PFOS concentration, disappearing at X DPPC ≤ 0.97. The main DPPC phase transition temperature showed a depression and peak broadening with increasing mole fraction of PFOS in both the DSC and the fluorescence anisotropy studies. From the melting point depression in the fluorescence anisotropy studies, which was observed at a concentration as low as 10 mg/L, an apparent partition coefficient of K = 5.7 × 10 4 (mole fraction basis) was calculated. These results suggest that PFOS has a high tendency to partition into lipid bilayers. These direct PFOS-DPPC interactions are one possible mechanism by which PFOS may contribute to adverse effects, for example neonatal mortality, in laboratory studies and possibly in humans.

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“…All experiments were carried out in triplicate. The pretransition and main phase transitions of DPPC are in good agreement with literature data [13,16].…”

Section: Differential Scanning Calorimetrysupporting

confidence: 90%

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Lehmler

Xie

Bothun

et al. 2006

Colloids and Surfaces B: Biointerfaces

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“…Similar results were also observed with the histone uptake on petunia protoplasts [25]. This may be due to the low-temperature-induced change in the physicochemical properties of cell membrane favoring higher cellular uptake of the peptides studied [25][26][27]. FDA staining test for protoplast viability revealed that viability (70-80%) was not significantly compromised at the concentration of CPP used and there was no significant deleterious effect of the nonfluorescent transportan treatment on the protoplast viability (65%).…”

Section: Resultssupporting

confidence: 74%

Cellular uptake of cell‐penetrating peptides pVEC and transportan in plants

Chugh

Eudes

2007

Journal of Peptide Science

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Internalization of fluorescently labeled CPPs, pVEC, transportan and scrambled pVEC, in a range of plant cells was investigated. Cellular uptake of the peptides was found to be tissue dependent. pVEC and transportan were distinctly internalized in triticale mesophyll protoplasts, onion epidermal cells, leaf bases and root tips of seven-day old triticale seedlings but showed negligible florescence in coleoptile and leaf tips as observed under a fluorescence microscope. Further, pVEC and transportan uptake studies were focused on mesophyll protoplasts as a system of investigation. In fluorimetric studies transportan showed 2.3 times higher cellular internalization than pVEC in protoplasts, whereas scrambled pVEC failed to show any significant fluorescence. Effect of various factors on cellular internalization of pVEC and transportan in protoplasts was also investigated. The cellular uptake of both the peptides was concentration dependent and nonsaturable. The cellular uptake of pVEC and transportan was enhanced at low temperature (4°C). The presence of endocytic/macropinocytosis inhibitors did not reduce the cellular uptake of the peptides, suggesting direct cell penetration, receptor-independent internalization of pVEC and transportan into the plant cells.

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“…The main transition occurs when the bilayer shifts from the gel state to the fluid state (Brandl, 2001;Huang and Li, 1999;Ladbrooke and Chapman, 1969). Changes in Tm when adding a drug compound indicate an effect on the molecular motion of the lipid chain (Beni et al, 2006).…”

Section: Differential Scanning Calorimetry (Dsc) To Examine Possible mentioning

confidence: 99%

Drug permeability across a phospholipid vesicle based barrier: 3. Characterization of drug–membrane interactions and the effect of agitation on the barrier integrity and on the permeability

Flaten¹,

Skar²,

Luthman³

et al. 2007

European Journal of Pharmaceutical Sciences

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Recently we reported on the development and structural characterization of a phospholipid vesicle based barrier useful for medium throughput screening of passive drug permeability.Here, we investigate the physical and functional integrity of the phospholipid vesicle based barriers to agitation by stirring or shaking, and whether agitation affects drug permeability of sulpiride, metoprolol and testosterone. In addition, three drugs (caffeine, naproxen and sulphasalazine) which were shown in a previous study to affect the electrical resistance of the barriers, were investigated for their influence on the permeability of a simultaneously applied hydrophilic marker (calcein), and on the thermotropic phase transition of the phospholipid bilayers using differential scanning calorimetry (DSC).Electrical resistance measurements indicated that the barriers should withstand shaking speeds up to 150 rpm without losing their integrity, but significant release of phospholipids from the membrane barriers to the donor and acceptor chambers was observed under agitation ≥150 rpm. When using agitation up to 100 rpm no increase in permeability was observed for sulpiride, metoprolol and testosterone. The phospholipid vesicle-based barrier thus differ from other permeability models in that agitation does not lead to an increase in permeability, not even for highly lipophilic drugs such as testosterone. This is explained by the different morphology of the vesicle-based barrier which is containing a 100 µm thick layer of mostly aqueous compartments immobilised within a matrix of phospholipids vesicles.Sulphasalazine and naproxen were shown to decrease the electrical resistance and increase the permeability of the hydrophilic marker calcein. The DSC experiments showed that these two drugs probably interact with the head groups of the phospholipids. In contrast, caffeine gave an increase in electrical resistance and a decrease in permeability of calcein. From the DSC experiments no signs of interaction of caffeine with the phospholipid bilayer could be observed.3

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Calorimetric and molecular mechanics studies of the thermotropic phase behavior of membrane phospholipids

Cited by 188 publications

References 68 publications

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Cellular uptake of cell‐penetrating peptides pVEC and transportan in plants

Drug permeability across a phospholipid vesicle based barrier: 3. Characterization of drug–membrane interactions and the effect of agitation on the barrier integrity and on the permeability

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