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Lithium Sensitivity of Store Operated Ca2+ Entry and Survival of Fibroblasts Isolated from Chorea-Acanthocytosis Patients

Pelzl, Lisann; Elsir, Bhaeldin; Sahu, Itishri; Bissinger, Rosi; Singh, Yogesh; Sukkar, Basma; Honisch, Sabina; Schoels, Ludger; Jemaà, Mohamed LU and Lang, Elisabeth, et al. (2017) In Cellular Physiology and Biochemistry 42. p.2066-2077
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... (More)

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.

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published
subject
keywords
Apoptosis, Calcium, Cell membrane scrambling, Lithium, Neurodegeneration, Orai1, SOCE
in
Cellular Physiology and Biochemistry
volume
42
pages
12 pages
publisher
Karger
external identifiers
  • scopus:85027720860
  • wos:000414026500028
ISSN
1015-8987
DOI
10.1159/000479901
language
English
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yes
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479379e6-0bcc-4ca9-89d0-00b1eef41670
date added to LUP
2017-09-07 12:07:31
date last changed
2018-01-17 14:14:37
@article{479379e6-0bcc-4ca9-89d0-00b1eef41670,
  abstract     = {<p>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 Ca<sup>2+</sup> 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 Ca<sup>2+</sup> activity ([Ca<sup>2+</sup>]<sub>i</sub>) was estimated from Fura-2-fluorescence, SOCE from increase of [Ca<sup>2+</sup>]<sub>i</sub> following Ca<sup>2+</sup> re-addition after Ca<sup>2+</sup>-store depletion with sarcoendoplasmatic Ca<sup>2+</sup>-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.</p>},
  author       = {Pelzl, Lisann and Elsir, Bhaeldin and Sahu, Itishri and Bissinger, Rosi and Singh, Yogesh and Sukkar, Basma and Honisch, Sabina and Schoels, Ludger and Jemaà, Mohamed and Lang, Elisabeth and Storch, Alexander and Hermann, Andreas and Stournaras, Christos and Lang, Florian},
  issn         = {1015-8987},
  keyword      = {Apoptosis,Calcium,Cell membrane scrambling,Lithium,Neurodegeneration,Orai1,SOCE},
  language     = {eng},
  month        = {08},
  pages        = {2066--2077},
  publisher    = {Karger},
  series       = {Cellular Physiology and Biochemistry},
  title        = {Lithium Sensitivity of Store Operated Ca<sup>2+</sup> Entry and Survival of Fibroblasts Isolated from Chorea-Acanthocytosis Patients},
  url          = {http://dx.doi.org/10.1159/000479901},
  volume       = {42},
  year         = {2017},
}