Effects of arachidonic acid on the lysosomal ion permeability and osmotic stability.
In this study, we investigated the effects of arachidonic acid, a PLA2-produced lipid metabolite, on the lysosomal permeability, osmotic sensitivity and stability. Through the measurements of lysosomal beta-hexosaminidase free activity, membrane potential, intralysosomal pH, and lysosomal latency loss in hypotonic sucrose medium, we established that arachidonic acid could increase the lysosomal permeability to both potassium ions and protons, and enhance the lysosomal osmotic sensitivity. As a result, the fatty-acid-promoted entry of potassium ions into the lysosomes via K+/H+ exchange, which could produce osmotic imbalance across their membranes and osmotically destabilize the lysosomes. In addition, the enhancement of lysosomal osmotic sensitivity caused the lysosomes to become more liable to destabilization in osmotic shock. The results suggest that arachidonic acid may play a role in the lysosomal destabilization.
Zhang
Gu
G
University of Science and Technology Beijing, Beijing, People's Republic of China.
Yi
Ya-Ping
YP
Zhang
Guo-Jiang
GJ
D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D002414:Cations, Monovalent / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D017136:Ion Transport; D008247:Lysosomes / Q000187:drug effects* / Q000378:metabolism; D008564:Membrane Potentials; D009995:Osmosis; D010539:Permeability; D011188:Potassium / Q000378:metabolism*; D011522:Protons; D051381:Rats; D013395:Sucrose / Q000493:pharmacokinetics; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism*
D002414:Cations, Monovalent; D011522:Protons; D016718:Arachidonic Acid; D013395:Sucrose; D001619:beta-N-Acetylhexosaminidases; D011188:Potassium