Pulsed Electric Fields Alter Expression of NF-κB Promoter-Controlled Gene.

The possibility to artificially adjust and fine-tune gene expression is one of the key milestones in bioengineering, synthetic biology, and advanced medicine. Since the effects of proteins or other transgene products depend on the dosage, controlled gene expression is required for any applications, where even slight fluctuations of the transgene product impact its function or other critical cell parameters. In this context, physical techniques demonstrate optimistic perspectives, and pulsed electric field technology is a potential candidate for a noninvasive, biophysical gene regulator, exploiting an easily adjustable pulse generating device. We exposed mammalian cells, transfected with a NF-κB pathway-controlled transcription system, to a range of microsecond-duration pulsed electric field parameters. To prevent toxicity, we used protocols that would generate relatively mild physical stimulation. The present study, for the first time, proves the principle that microsecond-duration pulsed electric fields can alter single-gene expression in plasmid context in mammalian cells without significant damage to cell integrity or viability. Gene expression might be upregulated or downregulated depending on the cell line and parameters applied. This noninvasive, ligand-, cofactor-, nanoparticle-free approach enables easily controlled direct electrostimulation of the construct carrying the gene of interest; the discovery may contribute towards the path of simplification of the complexity of physical systems in gene regulation and create further synergies between electronics, synthetic biology, and medicine.

Genotoxic properties of Betonica officinalis, Gratiola officinalis, Vincetoxicum luteum and Vincetoxicum hirundinaria extracts.

Genotoxicity of B. officinalis, G. officinalis, V. luteum and V. hirundinaria extracts, which demonstrated strong antioxidant capacity, was tested using chromosome aberration, sister chromatid exchange (SCE), cytokinesis-block micronucleus and alkaline single-cell gel electrophoresis (comet) assays in human lymphocytes in vitro and Ames Salmonella/microsome test. All tested extracts were not mutagenic in S. typhimurium strains TA98 and TA100 with and without metabolic activation and did not induce chromosome aberrations in human lymphocytes in vitro. Extract from G. officinalis was the only one, which induced significant increase in micronuclei, indicating possible aneugenic effect. All investigated plant extracts induced DNA damage evaluated by the comet assay, while B. officinalis and V. luteum extracts induced slight increase in SCE values. The determined variation in response might be due to the plant extract tested and donor susceptibility.

Genotoxicity and antioxidant activity of five Agrimonia and Filipendula species plant extracts evaluated by comet and micronucleus assays in human lymphocytes and Ames Salmonella/microsome test.

The species of Agrimonia and Filipendula have been traditionally used in folk medicine as anti-inflammatory herbs. This study extends the knowledge on bioactivities of F. palmata, A. eupatoria, A. procera, F. ulmaria and F. vulgaris by comprehensive characterization of their methanolic extracts. Antioxidant properties of extracts were evaluated by DPPH• (2,2-diphenyl-1-picrylhydrazyl), ABTS•+ 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) scavenging and oxygen radical absorbance capacities (ORAC). Genotoxicity of extracts was tested using alkaline single-cell gel electrophoresis (comet) and cytokinesis-block micronucleus assays in human lymphocytes in vitro and the Ames Salmonella/microsome test. All investigated Agrimonia and Filipendula extracts possessed strong antioxidant activity, which was comparable with that of a standard antioxidant trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid). Thirty five compounds belonging to the classes of phenolic acids, flavonoids, phenylpropanoids and ellagitanins were detected by ultra-performance liquid chromatography - mass spectrometry (UPLC-Q-TOF-MS). Agrimonia and Filipendula extracts induced an increase in a DNA damage in the comet assay expressed as mean percentage of DNA in the comet tail. However, these extracts did not produce reverse mutation in bacterial cells in the Ames test and were not genotoxic in the micronucleus test. However, a slight though significant decrease of nuclear division index values was determined. In general, this study proved that Agrimonia and Filipendula species are a good source of bioactive compounds; their extracts may be classified as non-mutagenic and non-clastogenic in vitro under conditions of the current study. Consequently, the plants may be a promising material for nutraceuticals and natural medicines.