Cargando…
Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes
BACKGROUND: In many cells, depletion of intracellular calcium (Ca(2+)) reservoirs triggers Ca(2+) entry through store-operated Ca(2+) channels in the plasma membrane. However, the mechanisms of agonist-induced calcium entry (ACE) in keratinocytes are not fully understood. OBJECTIVES: This study was...
Autores principales: | , , , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
Blackwell Publishing Ltd
2008
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658711/ https://www.ncbi.nlm.nih.gov/pubmed/18028502 http://dx.doi.org/10.1111/j.1365-2133.2007.08298.x |
_version_ | 1782165644739870720 |
---|---|
author | Ross, K Parker, G Whitaker, M Reynolds, NJ |
author_facet | Ross, K Parker, G Whitaker, M Reynolds, NJ |
author_sort | Ross, K |
collection | PubMed |
description | BACKGROUND: In many cells, depletion of intracellular calcium (Ca(2+)) reservoirs triggers Ca(2+) entry through store-operated Ca(2+) channels in the plasma membrane. However, the mechanisms of agonist-induced calcium entry (ACE) in keratinocytes are not fully understood. OBJECTIVES: This study was designed to determine if pharmacological inhibition of calcium-independent phospholipase A (iPLA(2)) impairs ACE in normal human epidermal keratinocytes. METHODS: Confocal laser scanning microscopy was used to monitor the dynamics of Ca(2+) signalling in keratinocytes loaded with the calcium-sensitive dye Fluo-4. Cells were stimulated with extracellular nucleotides [adenosine triphosphate (ATP) or uridine triphosphate (UTP)] or with lysophosphatidic acid (LPA), a bioactive lipid that regulates keratinocyte proliferation and differentiation. RESULTS: Both ATP and UTP induced Ca(2+) release in primary human keratinocytes. This was not followed by robust Ca(2+) influx when the experiments were performed in low Ca(2+) (70 μmol L(−1)) medium. Upon elevation of extracellular Ca(2+) to 1·2 mmol L(−1), however, a biphasic response consisting of an initial Ca(2+) peak followed by an elevated plateau was observed. The plateau phase was inhibited when cells were treated with bromoenol lactone, a specific pharmacological inhibitor of iPLA(2). These findings indicate that iPLA(2) activity is required for ACE in keratinocytes. LPA also evoked Ca(2+) release in keratinocytes but failed to induce sustained Ca(2+) entry even when extracellular Ca(2+) was elevated to 1·2 mmol L(−1). CONCLUSION: Our results demonstrate for the first time an important role for iPLA(2) in regulating ACE in primary human keratinocytes. |
format | Text |
id | pubmed-2658711 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2008 |
publisher | Blackwell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-26587112009-03-30 Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes Ross, K Parker, G Whitaker, M Reynolds, NJ Br J Dermatol Original Articles BACKGROUND: In many cells, depletion of intracellular calcium (Ca(2+)) reservoirs triggers Ca(2+) entry through store-operated Ca(2+) channels in the plasma membrane. However, the mechanisms of agonist-induced calcium entry (ACE) in keratinocytes are not fully understood. OBJECTIVES: This study was designed to determine if pharmacological inhibition of calcium-independent phospholipase A (iPLA(2)) impairs ACE in normal human epidermal keratinocytes. METHODS: Confocal laser scanning microscopy was used to monitor the dynamics of Ca(2+) signalling in keratinocytes loaded with the calcium-sensitive dye Fluo-4. Cells were stimulated with extracellular nucleotides [adenosine triphosphate (ATP) or uridine triphosphate (UTP)] or with lysophosphatidic acid (LPA), a bioactive lipid that regulates keratinocyte proliferation and differentiation. RESULTS: Both ATP and UTP induced Ca(2+) release in primary human keratinocytes. This was not followed by robust Ca(2+) influx when the experiments were performed in low Ca(2+) (70 μmol L(−1)) medium. Upon elevation of extracellular Ca(2+) to 1·2 mmol L(−1), however, a biphasic response consisting of an initial Ca(2+) peak followed by an elevated plateau was observed. The plateau phase was inhibited when cells were treated with bromoenol lactone, a specific pharmacological inhibitor of iPLA(2). These findings indicate that iPLA(2) activity is required for ACE in keratinocytes. LPA also evoked Ca(2+) release in keratinocytes but failed to induce sustained Ca(2+) entry even when extracellular Ca(2+) was elevated to 1·2 mmol L(−1). CONCLUSION: Our results demonstrate for the first time an important role for iPLA(2) in regulating ACE in primary human keratinocytes. Blackwell Publishing Ltd 2008-01 /pmc/articles/PMC2658711/ /pubmed/18028502 http://dx.doi.org/10.1111/j.1365-2133.2007.08298.x Text en Journal Compilation © 2007 British Association of Dermatologists http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation. |
spellingShingle | Original Articles Ross, K Parker, G Whitaker, M Reynolds, NJ Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title | Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title_full | Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title_fullStr | Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title_full_unstemmed | Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title_short | Inhibition of calcium-independent phospholipase A impairs agonist-induced calcium entry in keratinocytes |
title_sort | inhibition of calcium-independent phospholipase a impairs agonist-induced calcium entry in keratinocytes |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658711/ https://www.ncbi.nlm.nih.gov/pubmed/18028502 http://dx.doi.org/10.1111/j.1365-2133.2007.08298.x |
work_keys_str_mv | AT rossk inhibitionofcalciumindependentphospholipaseaimpairsagonistinducedcalciumentryinkeratinocytes AT parkerg inhibitionofcalciumindependentphospholipaseaimpairsagonistinducedcalciumentryinkeratinocytes AT whitakerm inhibitionofcalciumindependentphospholipaseaimpairsagonistinducedcalciumentryinkeratinocytes AT reynoldsnj inhibitionofcalciumindependentphospholipaseaimpairsagonistinducedcalciumentryinkeratinocytes |