Integrated in vitro - omics based approach to assess the heavy metals and their binary mixtures toxicity in hippocampal ht-22 cell line
- Autores: Venkatanaidu Karri
- Directores de la Tesis: Marta Schuhmacher Ansuategui (dir. tes.), Vikas Kumar (codir. tes.)
- Lectura: En la Universitat Rovira i Virgili ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Alexey Kolodkin (presid.), Jaume Folch López (secret.), Eliandre de Oliveira Cacheado (voc.)
- Programa de doctorado: Programa de Doctorado en Nanociencia, Materiales e Ingeniería Química por la Universidad Rovira i Virgili
- Materias:
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- Resumen
Many environmental pollutants have been associated with human diseases. In recent years, exposures to hazardous metals, such as pb, cd, as, and mehg are shown significant toxicological effects in brain. Our current knowledge of heavy metals (pb, cd, as, and mehg) induced adverse health effects is mainly limited to the individual level. The scientific community increasingly recognizes the adverse effects associated with metal mixtures are a serious concern. One of the major challenges for metals toxicology is to find how mixtures exert their effects on living organisms, due to mixtures toxicity studies on hippocampus is very limited. The regulatory frameworks such as reach in the eu are becoming more critical regarding the use of animal testing. Therefore, rational approaches are needed to assess the potential toxicity of mixtures by using the new tools, which should incorporate alternative animal experimental tools. Recent advancement in in vitro, and omics techniques may allow an accurate understanding of metal mixtures toxicity mechanism.
The advancement and development of in vitro and omics methods make them powerful tools for evaluation of single metals, and their binary mixtures exposure related early cellular changes and also the mode of toxicity on hippocampal cell lines. The main goal of this thesis was taking advantage of in vitro, label free proteomic technologies and system biology tools for assessing comparative toxicity signature profiling of heavy metals (pb, cd, as, and mehg) and their binary mixtures on the mice ht-22 hippocampal cell line. Thus, hippocampus relevant in vitro toxicity studies are could be more rational for understanding the potency of metal.
Firstly, we assumed that the mode of actions of individual metal toxicity can be used as a baseline for understanding potential mechanisms associated with mixture (pb, cd, as, and mehg) in hippocampus region. We showed that single metals cytotoxic effects and potency in different exposure conditions, in a pbcdasmehg as well as in genotoxicity and apoptosis in mice ht-22 hippocampal cells. We have also shown that metal mixtures interaction in by utilizing the dose addition, response addition models in chapter 3. These findings give significant evidence of the metal mixtures neurotoxic activity and their potential interactions depend on the composition of elements, cell line sensitivity.
However these studies have drawback to understand the underlying mechanism. Recent proteomic research has provided evidence that toxic chemical induce the expression of characteristic stress-related proteins in cells/organ. This opens the possibility of using these protein expression profiles (signatures) for the detection of heavy metals and their mixtures toxicity profile in ht-22 cells. The purpose of the chapter 4, 5 is to investigate the underlying mechanisms of the heavy metals toxicity by using a proteomic and system biology tools.
This enables to gain a global understanding of the way in which metal single (pb, as, mehg) and their mixtures response in the ht-22 cells related to neurodegenerative disease. The outcomes indicates that the single metals and their mixtures impact in critical molecular pathways such as ubiquitin proteasome system (ups), mrna splicing, oxidative stress and mitochondrial dysfunction and that these alterations also have a relation on the neurodegenerative diseases (alzhmer’s disease, parkinson’s disease). The multi-faceted comparison of the cellular responses to pb+mehg, pb+as, and mehg+as allowed us to get better insights into the responses of the interaction profile in protein level. In our results, pb+mehg induce detectable perturbation of the cellular functions than other two mixtures pb+as, mehg+as. We confirm that by analyzing complete cellular proteome and neurodegeneration related pathways, all of the evidence suggests that disruption occur by metal mixtures exposure is more hazardous than single metal exposure in ht-22 cells.
In future, refinement is needed in this research to validate quantitative risk assessment and to support the assumptions; These may include testing for some specific proteins dose–response curves, determining whether interaction assumptions are applicable or not for describing mixture risk.
