Lithium Sensitivity of Store Operated Ca2+ Entry and Survival of Fibroblasts Isolated from Chorea-Acanthocytosis Patients.
Cell Physiol Biochem
; 42(5): 2066-2077, 2017.
Article
em En
| MEDLINE
| ID: mdl-28803243
ABSTRACT
BACKGROUND:
The widely expressed protein chorein fosters activation of the phosphoinositide 3 kinase (PI3K) pathway thus supporting cell survival. Loss of function mutations of the chorein encoding gene VPS13A (vacuolar protein sorting-associated protein 13A) causes chorea-acanthocytosis (ChAc), a neurodegenerative disorder paralleled by deformations of erythrocytes. In mice, genetic knockout of chorein leads to enhanced neuronal apoptosis. PI3K dependent signalling upregulates Orai1, a pore forming channel protein accomplishing store operated Ca2+ entry (SOCE). Increased Orai1 expression and SOCE have been shown to confer survival of tumor cells. SOCE could be up-regulated by lithium. The present study explored, whether SOCE and/or apoptosis are altered in ChAc fibroblasts and could be modified by lithium treatment.METHODS:
Fibroblasts were isolated from ChAc patients and age-matched healthy volunteers. Cytosolic Ca2+ activity ([Ca2+]i) was estimated from Fura-2-fluorescence, SOCE from increase of [Ca2+]i following Ca2+ re-addition after Ca2+-store depletion with sarcoendoplasmatic Ca2+-ATPase (SERCA) inhibitor thapsigargin (1 µM), and apoptosis from annexin-V/propidium iodide staining quantified in flow cytometry.RESULTS:
SOCE was significantly smaller in ChAc fibroblasts than in control fibroblasts. Lithium (2 mM, 24 hours) significantly increased and Orai1 blocker 2-Aminoethoxydiphenyl Borate (2-APB, 50 µM, 24 hours) significantly decreased SOCE. Annexin-V-binding and propidium iodide staining were significantly higher in ChAc fibroblasts than in control fibroblasts. In ChAc fibroblasts annexin-V-binding and propidium iodide staining were significantly decreased by lithium treatment, significantly increased by 2-APB and virtually lithium insensitive in the presence of 2-APB.CONCLUSIONS:
In ChAc fibroblasts, downregulation of SOCE contributes to enhanced susceptibility to apoptosis. Both, decreased SOCE and enhanced apoptosis of ChAc fibroblasts can be reversed by lithium treatment.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neuroacantocitose
/
Fibroblastos
/
Canais de Cálcio Ativados pela Liberação de Cálcio
/
Lítio
Tipo de estudo:
Diagnostic_studies
/
Observational_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
Cell Physiol Biochem
Assunto da revista:
BIOQUIMICA
/
FARMACOLOGIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Alemanha