CPLA2: key enzyme for astroctytic cell membrane phase property change induced by abeta

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The interaction of amyloid beta peptide (A [beta]) and cell membrane is believed to be the basis of its biological function including its toxicity to neurons, thus it is important to understand how A [beta] affects cell membrane properties. Contradictory observations have been reported on A [beta]'s effect on membrane fluidity, possibly resulted from different target samples, distinct A [beta] types, A [beta] preparation procedure, various incubation time length and diverse testing techniques applied. Among all these variables, we suspect A [beta] treatment time length to be one of the most important factors that will affect the effect of A [beta] on cell membrane. Here, we reported an interesting time-dependent biphasic change pattern of DITNC cell membrane phase properties induced by oligomeric A [beta] ₁₋₄₂. A novel membrane phase property marker - Laurdan was applied in our study to reveal not only the overall membrane phase changes but also specific local membrane phase properties. The role of phospholipase A₂ (PLA₂) in the membrane phase property changes induced by oligomeric A [beta]₁₋₄₂ has also been tested. Based on our experimental results, a model was proposed to explain the time dependent biphasic membrane phase property change phenomenon and how A[beta] affects cell membrane phase properties.