Cell response to infection involves signalization pathways modulating the viral replication efficiency. Our laboratory has been studying these regulatory processes for long time especially in the case of Human Immunodeficiency Virus type 1 infection responsible for AIDS. We have identified several mechanisms modulating the viral replication involved in stress response, DNA repair  or in the interaction between retroviral nucleocomplexes and host chromatin. Activation of these pathways is expected to affect the cell biology and, thus, the distribution of chemical elements related to enzymatic activities involved in these regulatory processes. Furthermore, we have observed that treatment of cells using drugs that affect specific ionic exchange can strongly affect the viral replication (unpublished data).

Based on these data, we propose that the infection of cells by a retrovirus would induce a significant modification of the intracellular distribution of biological molecules and its chemical elements. Monitoring of these elements using Particule induced X-ray emission (PIXE) with Rutherford Backscattering Spectrometry (RBS) on the micro-beamline would allow us to identify i) new regulatory pathways and ii) new potential therapeutical targets. To this purpose we plan to use PIXE to compare the chemical distribution profile of cells transduced by retroviral vectors with non-transduced cells (293T, HeLaP4, Jurkat). The experiment will be then performed in cells modified, genetically (siRNA or CRISPR) or chemically, for some cellular pathways previously identified as potentially involved in the regulation of the viral replication.

Both the proteome and the transcriptome of HIV-1 infected cells are now well described. Our project will allow to decrypt the chemical distribution profile specific for HIV-1 infection which remains unknown to data. These experiments could be reproduced using vectors derived from other retroviral genus, or other viruses, in order to identify the cellular chemical distribution background (chemical distribution ID) specific for each viral infection constituting a new concept in virology.  The sample will be prepared with the help of Stephane Roudeau (CENBG ICS team) according to established protocols developed for PIXE analysis of culture cells.