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Proteomics, Metals and Differentiation team

Published on 24 January 2019



Team leader

Dr Thierry Rabilloud,
DR2 CNRS, HDR
Laboratoire Chimie et Biologie des Métaux
17 avenue des Martyrs
38 054 Grenoble cedex 9
Phone: 04 38 78 32 12
Fax: 04 38 78 44 99

Staff members

Projects

Names

Position

ETP

Macrophages and nanoparticles Thierry Rabilloud CNRS researcher
100%
Catherine Aude-Garcia CEA researcher
80%
Véronique Collin-Faure CEA technician
50%
Bacteria and nanoparticles Cécile Lelong Associate Pr. UJF
80%
Sylvie Luche UJF technician
80%
Radio-induced infammation Serge Candéias CEA researcher
100%
Isabelle Testard CEA researcher
100%

The research team develops three interconnected themes, in addition to technological developments for proteomics, running as a background project. The central project deals with the responses of myeloid cells to metallic ions and nanoparticles, and two other projects are connected to it. One project deals with the responses of the bacterium Bacillus subtilis to metallic ions and nanoparticles and also uses a combination of proteomic and targeted approaches. The third project is centered on molecular studies in radio-induced inflammation, with a focus on the activation and function of macrophages in this process.

General theme and rationale of the research project

An important part of the team studies how metallic ions and metallic oxides impact cells. For example, there is a clear relationship between various diseases and the phagocytosis of toxic (nano)particulate material by myeloid cells including macrophages, which are highly phagocytic. This is for example the case for asbestos and mesotheliomas, silica and silicosis, and this is also highly suspected for at least part of the toxic effects of tobacco smoke or diesel particles.
This relation is due to the primary scavenging function of some myeloid cells such as macrophages. When such cells phagocyte particles, they try to degrade them in their lysosomes. This can lead to the liberation of toxics adsorbed on the phagocytized particles. In the case of metal-containing particles, the toxics can be heavy metal ions or transition metal ions that will be dissolved by the acidic conditions prevailing in the lysosome. Besides such toxic effects, macrophage activation following phagocytosis of particulate material also results in the production of pro-inflammatory mediators, and this inflammation, if it becomes chronic, can be part of the etiology of some diseases such as cancer. Some of these factors are known, such as TNF, IL-6 or IL-12, but the complete scope of these proteins is not known yet.
There is thus a high interest to understand how myeloid cells and especially macrophages react to particles, and especially to metal containing nanoparticles, as well as the corresponding metallic ions. Our project goes beyond the simple observation of toxic effects, and aims at providing molecular mechanisms for a better understanding of the effects of these agents. Classically, this type of research is carried out by focused approaches on targets selected on the basis of previous knowledge; we will not neglect such approaches. However, we also believe that proteomics can deliver significant knowledge, owing to its wide and unbiased scope. Indeed, some work exists in this direction, either on the toxicity of metallic ions or on the effects of metallic oxide particles.
This mixed targeted-wide scope combination of approaches is also used when studying the responses of the soil bacterium Bacillus subtilis to nanoparticles, as this bacterium has an important ecotoxicological role.
Last but not least, the theme centered on radio-induced inflammation also studies the role of soluble mediators such as cytokines and chemokines in a model of sterile inflammation different from that induced by nanoparticles, in which myeloid cells most certainly have an important function. Work is also performed to identify the cellular factors involved in the production of these mediators.


Core research actions

Proteomics study of the effects of metals on cells

In this subproject, we study by proteomics the effects of metal ions and metallic particles on myeloid cells and on bacteria.
To investigate the effects of metallic particles and ions by proteomics, we use the same staggered strategy that we have used to investigate the differentiation of these cells. First, we will perform a comparative proteomics analysis at the scale of whole cell extracts. In this case, the fact that proteomics mainly shows the cellular stress response proteins will not be a problem, as this is exactly what we want to investigate, i.e. the details of the stress response that is made by the cells under the various conditions tested. Depending on the context and on the molecular responses revealed by this first stage, we can perform other proteomic studies (e.g. secretome, metalloproteomics via affinity chromatography).


Targeted studies

While proteomics offer the power of large scale and unbiased studies, its requirements in terms of sample consumption and its limitations in the analysis of lower abundance proteins does not make it a suitable tool for the detailed analysis of precise phenomena, especially for in vivo studies where the sample resources are often limited. This is why we also carry out targeted studies on the response of cells to various stimuli, including metals. As the scope of such studies can be overwhelmingly high, we use the know-how present in the team. These targeted studies can be focused on certain classes of molecules (e.g. cytokines, inflammasome), on core function of the macrophages (e.g. phagocytosis) or be used as a validation of the mechanisms highlighted by the proteomic analyses. Technically speaking, these studies use biochemistry as well as flow cytometry or qRT-PCR. As an example, our recent work on copper oxide nanoparticles drove us to investigate mitochondrial proteins and glutathione biosynthesis (Triboulet et al., Molecular and Cellular Proteomics, 2013).

Technology for proteomics

We are also deeply implicated in technological projects aiming at improving the performances of the proteomics toolbox, especially in the field of protein separation. We strongly believe that proteomics must continue to deal with complete proteins with their associated post-translational modifications, and cannot be reduced only to the study of digestion peptides, with the associated loss of filiation between the proteins and the peptides. We are thus working in the field of protein solubilization prior to electrophoresis, on the improvement of the electrophoretic methods per se, on the field of protein detection after gel and also on dedicated sample preparation methods fpr specific classes of proteins electrophoresis (see the associated bibliography of the team).

Insertion in the national and international context

Our team takes part in several national and international networks and initiatives, such as the national Labex SERENADE (centered on nanoparticles) or the EU network DOREMI (low doses irradiation).