Ca(2+)-dependent permeabilization of mitochondria and liposomes by palmitic and oleic acids: a comparative study

• Published in: Biochimica et biophysica acta Vol. 1838; no. 10; pp. 2600 - 2606
• Main Authors: Belosludtsev, Konstantin N, Belosludtseva, Natalia V, Agafonov, Alexey V, Astashev, Maxim E, Kazakov, Alexey S, Saris, Nils-Erik L, Mironova, Galina D
• Format: Journal Article
• Language: English
• Published: Netherlands 01.10.2014
• Subjects: Animals; Calcium - chemistry; Calcium - metabolism; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Liposomes - chemistry; Liposomes - metabolism; Mitochondria, Liver - chemistry; Mitochondria, Liver - metabolism; Mitochondrial Membrane Transport Proteins - chemistry; Mitochondrial Membrane Transport Proteins - metabolism; Mitochondrial Membranes - chemistry; Mitochondrial Membranes - metabolism; Oleic Acid - chemistry; Oleic Acid - metabolism; Oleic Acid - pharmacology; Palmitic Acid - chemistry; Palmitic Acid - metabolism; Palmitic Acid - pharmacology; Permeability; Rats; Rats, Wistar; Membrane permeabilization; Mitochondria; Liposomes; Calcium; Palmitic acid; Oleic acid
• ISSN: 0006-3002
• DOI: 10.1016/j.bbamem.2014.06.017

In the present work, we examine and compare the effects of saturated (palmitic) and unsaturated (oleic) fatty acids in relation to their ability to cause the Ca(2+)-dependent membrane permeabilization. The results obtained can be summarized as follows. (1) Oleic acid (OA) permeabilizes liposomal membranes at much higher concentrations of Ca(2+) than palmitic acid (PA): 1mM versus 100μM respectively. (2) The OA/Ca(2+)-induced permeabilization of liposomes is not accompanied by changes in the phase state of lipid bilayer, in contrast to what is observed with PA and Ca(2+). (3) The addition of Ca(2+) to the PA-containing vesicles does not change their size; in the case of OA, it leads to the appearance of larger and smaller vesicles, with larger vesicles dominating. This can be interpreted as a result of fusion and fission of liposomes. (4) Like PA, OA is able to induce a Ca(2+)-dependent high-amplitude swelling of mitochondria, yet it requires higher concentrations of Ca(2+) (30 and 100μM for PA and OA respectively). (5) In contrast to PA, OA is unable to cause the Ca(2+)-dependent high-amplitude swelling of mitoplasts, suggesting that the cause of OA/Ca(2+)-induced permeability transition in mitochondria may be the fusion of the inner and outer mitochondrial membranes. (6) The presence of OA enhances PA/Ca(2+)-induced permeabilization of liposomes and mitochondria. The paper discusses possible mechanisms of PA/Ca(2+)- and OA/Ca(2+)-induced membrane permeabilization, the probability of these mechanisms to be realized in the cell, and their possible physiological role.