| Autor: |
Fernandes, Denzyl, Zaidi, Asma, Bean, Jennifer, Hui, Dongwei, Michaelis, Mary L. |
| Předmět: |
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| Zdroj: |
Journal of Neurochemistry; Jul2007, Vol. 102 Issue 2, p454-465, 12p, 6 Graphs |
| Abstrakt: |
Intraneuronal calcium ([Ca2+]i) regulation is altered in aging brain, possibly because of the changes in critical Ca2+ transporters. We previously reported that the levels of the plasma membrane Ca2+-ATPase (PMCA) and the Vmax for enzyme activity are significantly reduced in synaptic membranes in aging rat brain. The goal of these studies was to use RNAi techniques to suppress expression of a major neuronal isoform, PMCA2, in neurons in culture to determine the potential functional consequences of a decrease in PMCA activity. Embryonic rat brain neurons and SH-SY5Y neuroblastoma cells were transfected with in vitro– transcribed short interfering RNA or a short hairpin RNA expressing vector, respectively, leading to 80% suppression of PMCA2 expression within 48 h. Fluorescence ratio imaging of free [Ca2+]i revealed that primary neurons with reduced PMCA2 expression had higher basal [Ca2+]i, slower recovery from KCl-induced Ca2+ transients, and incomplete return to pre-stimulation Ca2+ levels. Primary neurons and SH-SY5Y cells with PMCA2 suppression both exhibited significantly greater vulnerability to the toxicity of various stresses. Our results indicate that a loss of PMCA such as occurs in aging brain likely leads to subtle disruptions in normal Ca2+ signaling and enhanced susceptibility to stresses that can alter the regulation of Ca2+ homeostasis. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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