RNA--induced silencing of the plasma membrane Ca2+-ATPase 2 in neuronal cells: effects on Ca2+ homeostasis and cell viability.
J Neurochem
; 102(2): 454-65, 2007 Jul.
Article
em En
| MEDLINE
| ID: mdl-17488275
ABSTRACT
Intraneuronal calcium ([Ca(2+)](i)) regulation is altered in aging brain, possibly because of the changes in critical Ca(2+) transporters. We previously reported that the levels of the plasma membrane Ca(2+)-ATPase (PMCA) and the V(max) for enzyme activity are significantly reduced in synaptic membranes in aging rat brain. The goal of these studies was to use RNA(i) 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 [Ca(2+)](i) revealed that primary neurons with reduced PMCA2 expression had higher basal [Ca(2+)](i), slower recovery from KCl-induced Ca(2+) transients, and incomplete return to pre-stimulation Ca(2+) 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 Ca(2+) signaling and enhanced susceptibility to stresses that can alter the regulation of Ca(2+) homeostasis.
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Base de dados:
MEDLINE
Assunto principal:
Regulação para Baixo
/
Membrana Celular
/
Sinalização do Cálcio
/
Interferência de RNA
/
ATPases Transportadoras de Cálcio da Membrana Plasmática
/
Neurônios
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article