Cation-induced aggregation and fusion of N-acyl-N-methyl-phosphatidylethanolamine vesicles

Ortiz, Joana; Rosell, Francesc; Mora, Miguel A.; Madariaga, M. Africa de

doi:10.1016/0009-3084(92)90011-d

Cited by 6 publications

(6 citation statements)

References 29 publications

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“…This premise is based on data from animal systems that demonstrate the accumulation of NAPE only in degenerative conditions (13,14) and from biophysical studies of aqueous dispersions of NAPE, which indicate that these lipids stabilize a bilayer conformation where nonlamellar phases would otherwise be favored (22,29,30). Nevertheless, we have also established the influence of NAPE on the fusion properties of phospholipidic vesicles used as models of biomembranes (31).…”

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confidence: 96%

N‐Stearoyl‐phosphatidylserine: Synthesis and role in divalent‐cation‐induced aggregation and fusion

Morillo

Sagristá

Madariaga

1998

Lipids

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N-Acylphosphatidylserines have been isolated from intact and injured tissues, but the participation of such acidic phospholipids in membrane aggregation and fusion has not been demonstrated. We have synthesized N-stearoylphosphatidylserine (NSPS) and examined divalent-cation-induced aggregation of NSPS-liposomes, which leads to membrane destabilization and fusion. The purified lipid was characterized by its chromatographic and spectroscopic (infrared and 1H nuclear magnetic resonance) properties and by its chemical degradation pattern. Aggregation of unilamellar NSPS-liposomes was studied as a function of calcium and magnesium concentration. The ability of calcium and magnesium to induce vesicle aggregation is higher for phosphatidylserine (PS)-liposomes (threshold concentration 1.5 mM for calcium and 4.6 mM for magnesium) than for NSPS-liposomes (threshold concentration 2.8 mM for calcium and 6.6 mM for magnesium). The irreversibility of the aggregation reactions after adding EDTA suggests that vesicle fusion might occur in the presence of calcium and magnesium. Preliminary studies, based on mixing of both lipid and internal aqueous contents, show that fusion rather than aggregation of NSPS-liposomes occurs in the presence of calcium ions. The tendency of NSPS-liposomes to aggregate at higher cation concentrations than PS-liposomes suggests that N-acylation of phosphatidylserine protects the membrane against degenerative damage caused by aggregation and fusion.

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confidence: 96%

N‐Stearoyl‐phosphatidylserine: Synthesis and role in divalent‐cation‐induced aggregation and fusion

Morillo

Sagristá

Madariaga

1998

Lipids

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“…The results presented in this paper, together with the cited references (1,11,12,16,(19)(20)(21)(22)28,29), emphasize the fact that synthesis in vivo of N-acylated phospholipids can introduce important changes in membrane-mediated processes. The establishment of the real physiological meaning of the N-acylation reactions, which affect some membrane phospholipids, and the elucidation of the mechanisms by which the N-acylated constituents influence or modify the structure or dynamics of biological membranes are aims of our research.…”

Section: Discussionmentioning

confidence: 55%

“…NPPE was synthesized by condensing palmitoyl chloride with egg TPE as described previously (28). NPPS was obtained from PS, previously purified from a bovine brain extract, by means of an acylation reaction with palmitoyl chloride (29).…”

Section: Methodsmentioning

confidence: 99%

“…All these considerations, as well as our previous results (28,29), have led us to carry out a more exhaustive study of monovalent and divalent cation-induced aggregation, lipid exchange, and aqueous content mixing of sonicated unilamellar liposomes made from N-palmitoylphosphatidylethanolamine (NPPE) and N-palmitoylphosphatidylserine (NPPS) so as to demonstrate that fusion occurs. The influence of the polar head of both lipid species on the fusogenic properties of liposomes are also considered.…”

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confidence: 97%

“…We have previously reported the irreversible mono-and divalent cation-induced aggregation of liposomes prepared from a methylated analog of N-acylPE (28) and the divalent cation-induced fusion of N-stearoyl-PS liposomes (29). Our results have shown that the divalent cation concentrations necessary to induce the aggregation and fusion of liposomes containing N-acylaminophospholipids would be of physiological relevance in those pathological states in which the transient opening of calcium channels lead to an abrupt increase of calcium levels.…”

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confidence: 99%

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Aggregation and fusion of vesicles composed of N‐palmitoyl derivatives of membrane phospholipids

Mora

Mir

Madariaga

et al. 2000

Lipids

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N-Acylphosphatidylethanolamines and N-acylphosphatidylserines have been isolated from mammalian cells and have been associated with some tissue degenerative changes, although the relationship between their synthesis and the uncontrolled sequence of events that ends in irreversible tissue damage is not completely established. Our results show that monovalent and divalent cations induce aggregation and fusion of liposomes constituted by N-palmitoylphosphatidylethanolamine (NPPE) and N-palmitoylphosphatidylserine (NPPS). The effectiveness of cations to induce the aggregation of NPPE and NPPS liposomes is Ca2+ > Mg2+ >> Na+. NPPS liposomes aggregate at lower concentrations of divalent cations than NPPE liposomes, but with sodium NPPE liposomes aggregate to a higher extent than NPPS liposomes. The reaction order for the aggregation processes depends on the lipid and the cation nature and range from 1.04 to 1.64. Dynamic light scattering shows an irreversible increase of the size of the aggregates in the presence of all cations tested. The irreversibility of the aggregation process and the intermixing of bilayer lipids, as studied by resonance energy transfer assay, suggest that fusion, rather than aggregation, occurs. The existence of a real fusion was demonstrated by the coalescence of the aqueous contents of both NPPS and NPPE liposomes in the presence of either monovalent or divalent cations. The different binding sensitivity of Ca2+ to NPPS and NPPE liposomes, determined by zeta potential measurements, agrees with the results obtained in the aggregation and fusion assays. Our results suggest that the synthesis in vivo of N-acylated phospholipids can introduce important changes in membrane-mediated processes.

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The influence of N-acyl chain length on the phase behaviour of natural and synthetic N-acylethanolamine phospholipids

Domingo

Mora

Madariaga

1995

Chemistry and Physics of Lipids

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Cation-induced aggregation and fusion of N-acyl-N-methyl-phosphatidylethanolamine vesicles

Cited by 6 publications

References 29 publications

N‐Stearoyl‐phosphatidylserine: Synthesis and role in divalent‐cation‐induced aggregation and fusion

N‐Stearoyl‐phosphatidylserine: Synthesis and role in divalent‐cation‐induced aggregation and fusion

Aggregation and fusion of vesicles composed of N‐palmitoyl derivatives of membrane phospholipids

The influence of N-acyl chain length on the phase behaviour of natural and synthetic N-acylethanolamine phospholipids

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