Application of nanosecond pulsed electric fields (nsPEF) to various biological cell lines has been to shown to cause
many diverse effects, including poration of the plasma membrane, depolarization of the mitochondrial membrane,
blebbing, apoptosis, and intracellular calcium bursts. The underlying mechanism(s) responsible for these diverse
responses are poorly understood. Of specific interest in this paper are the long-term effects of nsPEF on cellular
processes, including the regulation of genes and production of proteins. Previous studies have reported transient
activation of select signaling pathways involving mitogen-activated protein kinases (MAPKs), protein
phosphorylation and downstream gene expression following nsPEF application. We hypothesize that nsPEF
represents a unique stimulus that could be used to externally modulate cellular processes. To validate our
hypothesis, we performed a series of cuvette-based exposures at 10 and 600ns pulse widths using a custom Blumlien
line pulser system. We measured acute changes in the plasma membrane structure using flow cytometry by tracking
phosphatidylserine externalization via FITC-Annexin V labeling and poration via propidium iodide uptake. We then
compared these results to viability of the cells at 24 hours post exposure using MTT assay and changes in the
MAPK family of proteins at 8 hours post-exposure using Luminex assay. By comparing exposures at 10 and 600ns
duration, we found that most MAPK family-protein expression increased in Jurkat and U937 cell lines following
exposure and compared well with drops in viability and changes in plasma membrane asymmetry. What proved
interesting is that some MAPK family proteins (e.g. p53, STAT1), were expressed in one cell line, but not the other.
This difference may point to an underlying mechanism for observed difference in cellular sensitivity to nsPEFinduced
stresses.
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Citation
Erick K. Moen ; Caleb C. Roth ; Caesar Cerna ; Larry Estalck ; Gerald Wilmink, et al.
"
Changes in protein expression of U937 and Jurkat cells exposed to nanosecond pulsed electric fields
", Proc. SPIE 8585, Terahertz and Ultrashort Electromagnetic Pulses for Biomedical Applications, 85850R (February 23, 2013); doi:10.1117/12.2005062; http://dx.doi.org/10.1117/12.2005062
