Characterization of lysophosphatidylcholine-induced changes of intracellular calcium in Drosophila S2 cells.
OBJECTIVE
Lysophosphatidylcholine (LPC), a bioactive lipid, regulates a wide array of biological processes. LPC could be deacylated to form glycerophosphocholine by neuropathy target esterase (NTE)/Swiss cheese protein (SWS). Although NTE/SWS is important in maintaining Ca(2+) homeostasis, the role of LPC in regulating the intracellular calcium concentration ([Ca(2+)]i) in Drosophila remains poorly understood. We aimed to study the mechanism of LPC-induced [Ca(2+)]i changes in Drosophila S2 cells.


METHODS
The [Ca(2+)]i of Drosophila S2 cells was measured by fluorescence spectrophotometry after loading the cells with the calcium-sensitive fluorescent probe Fura-2/AM.


RESULTS
Our results demonstrated that LPC could cause a rapid, dose-dependent increase in the [Ca(2+)]i in the presence of external calcium ([Ca(2+)]e). The LPC-induced [Ca(2+)]i increase was reduced by 60.7% in the absence of [Ca(2+)]e. Furthermore, the Ca(2+) influx was inhibited by 37.3% after the cells were preincubated with an L-type Ca(2+) channel blocker. In the Ca(2+)-free medium, the LPC-induced [Ca(2+)]i increase was completely blocked using an inositol triphosphate receptor (IP3R) inhibitor. However, a ryanodine receptor (RyR) inhibitor had no effect on the LPC-induced [Ca(2+)]i increase.


CONCLUSIONS
The LPC-induced [Ca(2+)]i increase in S2 cells was dependent on both the release of Ca(2+) stored in the endoplasmic reticulum and [Ca(2+)]e influx. Both L-type Ca(2+) channels and IP3R might be involved in this process. The LPC-induced [Ca(2+)]i increase in S2 cells characterized in this study may shed light on the study of NTE/SWS protein function in general because the enzyme is responsible for the deacylation of LPC.
Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.
Pan
P
Wang
Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.
Qi
Q
Wang
Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.
Lin
L
Yang
Group of Insect Virology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China. Electronic address: qinql@ioz.ac.cn.
Qi-Lian
QL
Qin
Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China. Electronic address: wuyj@ioz.ac.cn.
Yi-Jun
YJ
Wu
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002478:Cells, Cultured; D004330:Drosophila; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D016257:Fura-2 / Q000008:administration & dosage / Q000031:analogs & derivatives; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D020746:Calcium Channels, L-Type; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008244:Lysophosphatidylcholines; C049925:fura-2-am; D002118:Calcium; D016257:Fura-2
Drosophila S2 cells; Inositol triphosphate receptor; Intracellular calcium; L-type calcium channel; Lysophosphatidylcholine