Activation Of Detoxification Mechanisms Research Articles

Genotoxicity Assessment of Quinoin, a Ribosome Inactivating Protein from Quinoa Seeds, in the Teleost Danio rerio.

Ribosome inactivating proteins (RIPs) are N-glycosylases found in various plants that are able to specifically and irreversibly inhibit protein translation, thereby leading to cell death. Their cytotoxic properties have attracted attention in the medical field in the context of developing new anticancer therapies. Quinoin is a novel toxic enzyme obtained from quinoa seeds and classified as a type 1 RIP (Chenopodium quinoa Willd.). Recently, quinoin was found to be cytotoxic to normal fibroblasts and keratinocytes in vitro, as well as to several tumor cell lines. The aim of this study was to evaluate the in vitro and in vivo genotoxicity of quinoin in a zebrafish model. We evaluated its ability to induce DNA fragmentation, genomic instability, and reactive oxygen species (ROS) generation by means of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) reaction, randomly amplified polymorphic DNA (RAPD) Polymerase Chain Reaction (PCR) technique, and dichlorofluorescine (DCF) assay, respectively. Quinoin was found to cause genomic damage in zebrafish, as shown by DNA fragmentation, polymorphic variations leading to genomic instability, and oxidative stress. Interestingly, longer quinoin treatment caused less damage than shorter treatments. This study demonstrated ROS-mediated genotoxicity of quinoin toward the zebrafish genome. The reduced damage observed after longer quinoin treatment could indicate the activation of detoxification mechanisms, activation of repair mechanisms, or the loss of protein activity due to enzymatic digestion. In order to clarify the genotoxic actions of quinoin, further investigations of the response pathways to DNA damage are needed. Overall, the ability of quinoin to cause breaks and instability in DNA, together with its clear cytotoxicity, make it an interesting candidate for the development of new drugs for cancer treatment.

The ovaries of ivermectin-resistant Rhipicephalus microplus strains display proteomic adaptations involving the induction of xenobiotic detoxification and structural remodeling mechanisms

Controlling Rhipicephalus microplus is among the most significant challenges for livestock production worldwide. The indiscriminate use of acaricides stimulates the selection of resistant tick populations and is therefore ineffective. Understanding the molecular foundations of resistance could help inform the search for new alternatives for tick control. Although the ovary has been suggested as a relevant target organ for tick control, there are few existing studies that focus on tick ovarian tissue. Therefore, we conducted a comparative proteomic analysis on ovaries of R. microplus strains with differential resistance to ivermectin. In resistant ticks, we observed the over-accumulation of proteins involved in several biological processes, including translation, proteolysis, transport, cellular organization, differentiation, and xenobiotic detoxification. We also observed the accumulation of many structural and extracellular proteins such as papilin-like protein, which glycosylation increase its stability-based molecular modeling. Therefore, we propose that ovaries of ivermectin-resistant ticks overcome the negative impact of ivermectin through the activation of detoxification mechanisms and structural proteins associated with the remodeling of the ovary's extracellular matrix. SignificanceUnderstanding the molecular foundation of ivermectin resistance in Rhipicephalus microplus represents an essential step in cattle farming, which could provide clues and alternatives for tick control. Excessive use of chemicals like ivermectin allows the generation of resistant tick strains in different countries. However, limited molecular information is available concerning the tick's resistance to ivermectin. Detailed proteomics scrutiny in various tick organs will provide more comprehensive molecular information. Thus, we conducted an ovary comparative proteomic-based TMT-SPS-MS3 approach. We highlight in ivermectin-resistant ticks the over-accumulation of structural proteins and enzymes connected to detoxification mechanisms.

Zebrafish (Danio rerio) ability to activate ABCC transporters after exposure to glyphosate and its formulation Roundup Transorb®

The emergent demand for food production has increased the widespread use of pesticides, especially glyphosate-based herbicides as they can protect different types of crops, especially transgenic ones. Molecules of glyphosate have been found in water bodies around the world, and its presence can cause negative effects on non-target organisms, such as fish. Glyphosate toxicity appears to be systemic in fish but does not affect their organs equally. Also, its formulations can be more toxic than pure glyphosate. In this sense, we investigated if these variations in toxicity could be related to ATP binding cassette subfamily C (ABCC) transporters and the cellular detoxification capacity, following exposure to herbicides. Thus, adults of Danio rerio were exposed (24 and 96 h) to glyphosate and Roundup Transorb® (RT) at an environmental concentration of 0.1 mg/L, and the activity of ABCC proteins and gene expression of five isoforms of ABCC were analyzed. Glyphosate and RT exposure increased ABCC protein activity and gene expression up to 3-fold when compared to controls, indicating the activation of detoxification mechanisms. Only in the brain of D. rerio, the exposure to RT did not stimulate the activity of ABCC proteins, neither the expression of genes abcc1 and abcc4 that responded to the exposure to pure glyphosate. These results may suggest that the brain is more sensitive to RT than the other target-tissues since the mechanism of detoxification via ABCC transporters were not activated in this tissue as it was in the other.

PB1888 FEATURES OF CYSTEIN-RICH PROTEIN METALLOTHIONEIN FUNCTIONING IN CHRONIC B-LYMPHOCYTIC LEUKEMIA CELLS

Background: The main approach to the hematological cancers treatment is an intensive chemotherapy. However, often its ineffectiveness could be result of the phenomenon of multiple drug resistance (MDR) – immunity of cancer cells to cytostatic drugs. The most important MDR pathways are increased drug efflux resulting in reduced its accumulation, activation of detoxification mechanisms in tumor cells, altered activities of certain enzymes and level of intracellular thiols such as metallothioneins or reduced glutathione which bind compounds toxic for cells. Study and comprehension of these mechanisms will enable the design of suitable techniques and procedures for malignant tumor treatment. Aims: To investigate the level of expression of cystein-rich proteins metallothioneins in lymphocytes of patients with chronic B-lymphocytic leukemia (B-CLL) and to find out their role in the maintenance of redox state under this pathological state. Methods: Lymphocytes were separated from the B-CLL patient's and healthy donor's peripheral blood by density gradient centrifugation on histopaque. Monoclonal antibodies UC1MT (Abcam), UIC2 (Immunotech), MRP1 (R&D) were used to evaluate MTs I-II types, ABCB1, ABCC1 expression, respectively. Reactive oxygen species (ROS) level was assessed using fluorescent probe CM-H2DCFDA (Invitrogen). All investigations were carried out on the FACScanto II (BD). Results: A significant reduction (1.5–2.0-fold) of the MT expression level in B-CLL lymphocytes in comparison to the last one in healthy donors was reveled, despite the proven role of this protein in the detoxification processes from drugs. Additionally a comparative evaluation of expression of the membrane protein-transporters ABC family associated with MDR – ABCB1/P-gp and ABCC1/MRP1 was conducted. Theirs significant rise was found in tested group of B-CLL patients. Moreover, the rise of the ABCC1/ABCB1 expression ratio in leukemia cells reveled under enhanced ROS level compare to normal cells. Summary/Conclusion: Thus, in B-CLL cells the role of MT in the maintaining of redox state (ROS sequestration) is decreased under the rise of ABCC1 function. It is clear that the potential of MT as the scavengers of ROS is not fully understood, but the present data show that this protein could be selected as a target for novel treatment strategies for patients with leukemia.

Low levels of Cd induce persisting epigenetic modifications and acclimation mechanisms in the earthworm Lumbricus terrestris.

Toxic effects of cadmium (Cd), a common soil pollutant, are still not very well understood, particularly in regard to its epigenetic impact. Therefore, the aim of this study was to assess DNA methylation changes and their persistence in the earthworm Lumbricus terrestris upon chronic low dose Cd exposure using methylation sensitive amplification polymorphism (MSAP). Moreover, the biomarker response and fitness of the earthworms, as well as the expression of detoxification-related genes (metallothionein (MT) and phytochelatin synthase (PCS)) was evaluated. Low levels of Cd caused an increase in genome-wide DNA methylation, which remained partly modified, even after several months of recovery in unpolluted soil. Increased cellular stress seemed to decrease after two weeks of exposure whereas fitness parameters remained unaffected by Cd, probably as a result from the activation of detoxification mechanisms like the expression of MTs. Interestingly, even though the level of Cd exposure was very low, MT expression levels indicate the development of acclimation mechanisms. Taken together, this study demonstrates that acclimation, as well as epigenetic modifications can occur already in moderately polluted environments. In addition, these effects can have long-lasting impacts on key species of soil invertebrates and might persist long after the actual heavy metal challenge has passed.

Effects of heavy metals on Cyanothece sp. CCY 0110 growth, extracellular polymeric substances (EPS) production, ultrastructure and protein profiles.

This work shows the holistic effects of different heavy metals on the cells of the highly efficient EPS-producer the cyanobacterium Cyanothece sp. CCY 0110. The growth/survival, EPS production, ultrastructure, protein profiles and stress response were evaluated. The knowledge generated by this study will contribute to the implementation of heavy-metal removal systems based on cyanobacteria EPS or their isolated polymers.

Green Tea Consumption Is Associated with Decreased DNA Damage among GSTM1-Positive Smokers Regardless of Their hOGG1 Genotype

The levels of tobacco-related DNA adducts in human tissues reflect a dynamic process that is dependent on the intensity and time of exposure to tobacco smoke, the metabolic balance between activation of detoxification mechanisms, and the removal of adducts by DNA repair and/or cell turnover. Urinary 8-hydroxydeoxyguanosine (8-OHdG) is probably 1 of the most abundant DNA lesions formed during oxidative stress and is proposed as a sensitive biomarker of the overall oxidative DNA damage and repair. We performed this study to determine whether there were differences in increased oxidative stress susceptibility to smoking within the combined GSTM1 and hOGG1 genotypes and the impact of green tea drinking on this. We completed a Phase II randomized, controlled, 3-arm tea intervention trial to study the effect of high consumption of decaffeinated green or black tea or water on urinary 8-OHdG among heavy smokers and to evaluate the roles of GSTM1 and hOGG1 genotypes as effect modifiers. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed a significant effect of green tea consumption (P = 0.001). The change from baseline was significant in all GSTM1-positive smokers regardless of their hOGG1 genotype. Our data show that consumption of 4 cups (960 mL) of tea/d is a feasible and safe approach and was associated with a significant decrease in urinary 8-OHdG among green tea consumers. Our finding also suggests that green tea intervention might be effective in decreasing DNA damage in the subgroup of smokers who are GSTM1 positive regardless of their hOGG1 genotype.