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Low frequency MFs increased inositol 1,4,5-trisphosphate levels in the Jurkat cell line
I L Korzh-Sleptsova1, E Lindström, K H Mild
1Department of Cell and Molecular Biology, University of Umeå, Sweden.
Abstract:
We have earlier reported that when a weak 50 Hz MF (magnetic field) was applied, the leukemic T-cell line Jurkat responded with intracellular calcium oscillations [Lindström, et al., J. Cell Physiol., 156 (1993) 395-398]. The result suggested that the MF interfered with the signal transduction, although neither target molecules nor molecular mechanisms are at present known. In this study we found that application of a MF to Jurkat cells resulted in significant increase of inositol 1,4,5-trisphosphate (IP3) levels. Chelation of intracellular calcium ions by BAPTA/AM, did not block the increase of IP3 induced by MF. This result implied that MF-induced Ca2+ oscillations were not due to direct stimulation of the Ca(2+)-dependent phospholipase C-gamma 1 (PLC-gamma 1).
Insights
Weak magnetic fields (MF) cause calcium oscillations in Jurkat cells, suggesting signal transduction interference. This study found MF increases inositol 1,4,5-trisphosphate (IP3) levels, independent of calcium, indicating a novel signaling pathway.
Area of Science:
- Cellular Biology
- Biophysics
- Signal Transduction
Background:
- Previous research demonstrated that weak 50 Hz magnetic fields (MF) induce intracellular calcium oscillations in the Jurkat T-cell line.
- This phenomenon suggested MF interference with cellular signal transduction pathways, but the underlying molecular targets and mechanisms remained unknown.
Purpose of the Study:
- To investigate the molecular mechanisms by which magnetic fields affect signal transduction in Jurkat cells.
- To determine if MF-induced calcium oscillations are linked to the production of inositol 1,4,5-trisphosphate (IP3).
Main Methods:
- Jurkat cells were exposed to a weak 50 Hz magnetic field.
- Intracellular levels of inositol 1,4,5-trisphosphate (IP3) were measured.
- The effect of chelating intracellular calcium ions using BAPTA/AM on MF-induced IP3 increase was assessed.
Main Results:
- Application of a magnetic field to Jurkat cells resulted in a significant increase in inositol 1,4,5-trisphosphate (IP3) levels.
- Chelation of intracellular calcium ions did not prevent the MF-induced increase in IP3.
- This suggests that MF-induced calcium oscillations are not caused by direct stimulation of calcium-dependent phospholipase C-gamma 1 (PLC-gamma 1).
Conclusions:
- Magnetic fields can modulate intracellular signaling pathways in Jurkat cells, leading to increased IP3 production.
- The observed increase in IP3 is independent of intracellular calcium levels, implying a novel signaling mechanism.
- The findings challenge the hypothesis that MF-induced calcium oscillations are solely mediated by direct activation of PLC-gamma 1.