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Dissection of Local Ca2+ Signals in Cultured Cells by Membrane-targeted Ca2+ Indicators
Published on: March 22, 2019
Echinacea-induced cytosolic Ca2+ elevation in HEK293
Lankun Wu1, Eric W Rowe, Ksenija Jeftinija
1Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA.
BMC Complementary and Alternative Medicine
|November 25, 2010
Summary
Unidentified Echinacea purpurea compounds elevate calcium in non-immune cells via phospholipase C and IP3 receptors, distinct from CB2 pathways. This suggests novel immune-modulating mechanisms for Echinacea beyond known alkamides.
Area of Science:
- Pharmacology
- Immunology
- Cell Signaling
Background:
- Echinacea preparations are widely used for immune support, with alkamides targeting cannabinoid type 2 (CB2) receptors proposed as a mechanism.
- This study investigates Echinacea's effects on intracellular calcium (Ca2+) in non-immune cells, exploring pathways independent of CB2 receptors.
Purpose of the Study:
- To identify compounds in Echinacea purpurea root extracts that modulate intracellular Ca2+ levels in non-immune cells.
- To elucidate the signaling pathway involved in Echinacea-induced Ca2+ elevation in HEK293 cells.
Main Methods:
- Human embryonic kidney 293 (HEK293) cells were used to assess E. purpurea root extracts and constituents.
- Intracellular Ca2+ levels were monitored using calcium imaging, with inhibitors of phospholipase C (U73122) and inositol-1,4,5-trisphosphate (IP3) receptors (2-APB) employed.
- High-performance liquid chromatography (HPLC) fractionation and gas chromatography-mass spectrometry (GC-MS) were used to identify active compounds.
Main Results:
- E. purpurea extracts rapidly increased cytosolic Ca2+ in HEK293 cells, dependent on phospholipase C and IP3 receptors.
- CB2 receptor antagonists did not block these effects, indicating CB2 independence.
- Unknown lipophilic constituents, not alkamides, were associated with the observed Ca2+ response, suggesting a novel mechanism.
Conclusions:
- Echinacea constituents stimulate Ca2+ release via IP3 receptors and phospholipase C in non-immune cells.
- This pathway differs from the CB2 receptor-mediated pathway observed in immune cells, highlighting distinct Echinacea actions.
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