scholarly journals What do we actually see in intracellular SERS? Investigating nanosensor-induced variation

2017 ◽  
Vol 205 ◽  
pp. 409-428 ◽  
Author(s):  
J. Taylor ◽  
J. Milton ◽  
M. Willett ◽  
J. Wingfield ◽  
S. Mahajan
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Stress ◽  
Confocal Imaging ◽  
Plasmonic Nanoparticles ◽  
Oxygen Species ◽  
Inflammatory Genes ◽  
Biochemical Assays ◽  
Icp Ms ◽  
Induced Changes ◽  
Normal Cellular Metabolism

Plasmonic nanoparticles (NPs), predominantly gold (AuNPs), are easily internalised into cells and commonly employed as nanosensors for reporter-based and reporter-free intracellular SERS applications. While AuNPs are generally considered non-toxic to cells, many biological and toxicity studies report that exposure to NPs induces cell stress through the generation of reactive oxygen species (ROS) and the upregulated transcription of pro-inflammatory genes, which can result in severe genotoxicity and apoptosis. Despite this, the extent to which normal cellular metabolism is affected by AuNP internalisation remains a relative unknown along with the contribution of the uptake itself to the SERS spectra obtained from within so called ‘healthy’ cells, as indicated by traditional viability tests. This work aims to interrogate the perturbation created by treatment with AuNPs under different conditions and the corresponding effect on the SERS spectra obtained. We characterise the changes induced by varying AuNP concentrations and medium serum compositions using biochemical assays and correlate them to the corresponding intracellular reporter-free SERS spectra. The different serum conditions lead to different extents of nanoparticle internalisation. We observe that changes in SERS spectra are correlated to an increasing amount of internalisation, confirmed qualitatively and quantitatively by confocal imaging and ICP-MS analysis, respectively. We analyse spectra and characterise changes that can be attributed to nanoparticle induced changes. Thus, our study highlights a need for understanding condition-dependent NP-cell interactions and standardisation of nanoparticle treatments in order to establish the validity of intracellular SERS experiments for use in all arising applications.

scholarly journals Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein

2005 ◽  
Vol 392 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Lin Lin ◽  
Teresa M. Stringfield ◽  
Xianglin Shi ◽  
Yan Chen
Keyword(s):  
Reactive Oxygen Species ◽  
Transcriptional Regulation ◽  
Stress Response ◽  
Reactive Oxygen ◽  
Human Keratinocytes ◽  
Cell Stress ◽  
Oxygen Species ◽  
Response Gene ◽  
Enhancer Binding Protein ◽  
Stress Response Gene

RTP801 is a newly discovered stress-response gene that is induced by hypoxia and other cell stress signals. Arsenic is a heavy metal that is linked to carcinogenesis in humans. Here, we investigated the mechanism by which arsenic induces RTP801 transcription. In HaCaT human keratinocytes, arsenite was able to induce a rapid rise in the RTP801 mRNA level. Correspondingly, arsenite treatment was capable of stimulating a 2.5 kb human RTP801 promoter. Such a stimulatory effect was inhibited by co-expression of superoxide dismutase or glutathione peroxidase, and was abrogated by N-acetylcysteine, implying that ROS (reactive oxygen species) were involved in transcriptional regulation of the RTP801 gene. A series of deletion studies with the promoter revealed a critical arsenic-responsive region between −1057 and −981 bp of the promoter. Point mutations of the putative Elk-1 site and the C/EBP (CCAAT/enhancer-binding protein) site within this region were able to reduce the stimulatory effect of arsenite, indicating that Elk-1 and C/EBP are involved in transcriptional regulation of the RTP801 gene by arsenite. Furthermore, a gel mobility-shift assay demonstrated that arsenite was able to mount the rapid formation of a protein complex that bound the arsenic-responsive region as well as the C/EBP-containing sequence. The arsenite stimulation on RTP801 transcription was partly mediated by the ERK (extracellular-signal-regulated kinase) pathway, since the effect of RTP801 was inhibited by a selective ERK inhibitor. In addition, overexpression of Elk-1 and C/EBPβ was able to elevate the promoter activity. Therefore these studies indicate that RTP801 is a transcriptional target of arsenic in human keratinocytes, and that arsenic and ROS production are linked to Elk-1 and C/EBP in the transcriptional control.

scholarly journals Mechano-arrhythmogenicity is enhanced during late repolarisation in ischemia and driven by a TRPA1-, calcium-, and reactive oxygen species-dependent mechanism

2021 ◽  
Author(s):  
Breanne Ashleigh Cameron ◽  
T Alexander Quinn
Keyword(s):  
Reactive Oxygen Species ◽  
Ventricular Myocytes ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cellular Mechanisms ◽  
Sustained Activity ◽  
Intracellular Ca ◽  
Rabbit Ventricular Myocytes ◽  
Induced Changes ◽  
Dependent Mechanism

Background: Cardiac dyskinesis in regional ischemia results in arrhythmias through mechanically-induced changes in electrophysiology ('mechano-arrhythmogenicity') that involve ischemic alterations in voltage-calcium (Ca2+) dynamics, creating a vulnerable period (VP) in late repolarisation. Objective: To determine cellular mechanisms of mechano-arrhythmogenicity in ischemia and define the importance of the VP. Methods and Results: Voltage-Ca2+ dynamics were simultaneously monitored in rabbit ventricular myocytes by dual-fluorescence imaging to assess the VP in control and simulated ischemia (SI). The VP was longer in SI than in control (146±7 vs 54±8 ms; p<0.0001) and was reduced by blocking KATP channels with glibenclamide (109±6 ms; p<0.0001). Cells were rapidly stretched (10-18% increase in sarcomere length over 110-170 ms) with carbon fibres during diastole or the VP. Mechano-arrhythmogenicity, associated with stretch and release in the VP, was greater in SI than control (7 vs 1% of stretches induced arrhythmias; p<0.005) but was similar in diastole. Arrhythmias during the VP were more complex than in diastole (100 vs 69% had sustained activity; p<0.05). In the VP, incidence was reduced with glibenclamide (2%; p<0.05), by chelating intracellular Ca2+ (BAPTA; 2%; p<0.05), blocking mechano-sensitive TRPA1 (HC-030031; 1%; p<0.005), or by scavenging (NAC; 1%; p<0.005) or blocking reactive oxygen species (ROS) production (DPI; 2%; p<0.05). Ratiometric Ca2+ imaging revealed that SI increased diastolic Ca2+ (+9±1%, p<0.0001), which was not prevented by HC-030031 or NAC. Conclusion: In ischemia, mechano-arrhythmogenicity is enhanced specifically during the VP and is mediated by ROS, TRPA1, and Ca2+.

Reactive oxygen species downregulate the expression of pro-inflammatory genes by human chondrocytes

2003 ◽  
Vol 52 (3) ◽  
pp. 111-118 ◽  
Author(s):  
P. Devel ◽  
G. Deby-Dupont ◽  
J.-P. Pujol ◽  
J.-Y. Reginster ◽  
G. Martin ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Human Chondrocytes ◽  
Oxygen Species ◽  
Inflammatory Genes

scholarly journals Towards an Understanding of Specific Response of Metallothionein (Sub)Isoforms to Exposure to Platinum-Based Anticancer Drugs

2019 ◽  
Vol 67 (6) ◽  
pp. 1407-1417
Author(s):  
Sofie Blížkovská
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Free Radicals ◽  
Fluorescence Microscopy ◽  
Cancer Cells ◽  
Protein Level ◽  
Poor Prognosis ◽  
Cell Stress ◽  
Specific Response ◽  
Oxygen Species

Metallothioneins (MTs) are small cysteine-rich proteins involved in a number of pathophysiological processes. Particularly their linkage to cancer processes has been vastly studied and it is well known that MTs can inactivate metal-based cytostatics or scavenge free radicals. These processes result in pronounced chemoresistance and a poor prognosis for patients. Despite this knowledge, involvement of specific (sub)isoforms into this phenomenon requires further elucidation. Our results identified CisPt as the cytostatic which provoked the highest cell death exp followed by CarboPt and OxaliPt. Fluorescence microscopy visualized the oxidative cell stress. After application of 24hIC50 values, the reactive oxygen species (ROS) were visually produced. Our results also showed that MT 1, 2 and 3 expression manifested the highest qPCR activity after CisPt treatment (both healthy and cancer cells). While evaluating the expression of the protein level in the healthy and cancer cells treated by the cytotoxics we concluded that for MT1 and MT3 it was low under all three cytostatic treatments. Cancer cells had higher protein expression levels than healthy cells. In case of MT1/2 for cancer cells was highest under CisPt treatment.

Anoxia-induced changes in reactive oxygen species and cyclic nucleotides in the painted turtle

2007 ◽  
Vol 177 (4) ◽  
pp. 473-481 ◽  
Author(s):  
Matthew Edward Pamenter ◽  
Michael David Richards ◽  
Leslie Thomas Buck
Keyword(s):  
Reactive Oxygen Species ◽  
Cyclic Nucleotides ◽  
Reactive Oxygen ◽  
Painted Turtle ◽  
Oxygen Species ◽  
Induced Changes
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