DC projects

Research project

Understanding the functional impact of eif2ak mutants in dendritic cell and Interferonopathies

Rationale and Objectives

The cellular Integrated Stress Response (ISR) mechanism reduces protein synthesis in response to stress, while establishing a transcriptional program favoring stress resolution and cell survival through the activation of EIF2A kinases. Upon immune system unbalance, Plasmacytoid dendritic cells (pDC), monocytes and B cells can fuel auto-immunity by abnormally releasing cytokines and type-I Interferon (IFN) that contribute to disease recurrence. We showed that molecules in the cellular integrated stress response (ISR), such as PERK (EIF2AK3) are required to produce type-I IFN in response to nucleic acids (NA) or toxins, key events in Interferonopathies onset and flairs. We have identified, in collaboration with the F. Rieux-Laucat (IHU Imagine, Paris), new rare human variants with increased susceptibility to familial Systemic Lupus Erythematosus (SLE) and STING-associated vasculopathy in infancy (SAVI) patients displaying mutations in various eif2ak genes, including eif2ak3/perk. We will focus on pDC, that display ISR-like features and produce recurrently type-I IFN during interferonopathies.

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1) Study how ISR induction in pDC leads type-I IFN production, which becomes pathogenic in susceptible individuals bearing mutations in eif2ak genes. Cell biology methodologies, as well as protein synthesis, energy metabolism and cytokines monitoring by advanced flow cytometry will be performed on Cas9 engineered differentiated HSCs and transformed cell models, as well as on PBMCs.

2)  Identify the gene/mutation-specific omics signatures in mutated patient or engineered model cell lines. Ribo-seq analysis and proximity biotinylation identification (BIO-ID) by mass spectrometry will be performed to reveal the molecular networks linking different ISR molecular players to the innate immunity signaling pathways, like the anti-viral STING adaptor and ultimately type-I IFN production and/or activation of the JAK/STAT pathways.

3) Characterize using cell biology and immunology approaches the crosstalk between microbe or toxin sensing and the ISR in pDCs the potentially contributes to interferonopathies onset by potentializing the responses in mutated cells.

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Expected results

Cell biology characterization, Omics datasets on RNA-Seq, Ribo-seq and proteome on patients and cells with eif2ak mutations and matched controls. Molecular networks identification, PhD thesis, publication

Planned secondments

IJC (Ballestar) and OSR (Di Micco) to learn in vitro differentiation protocols of immune cells and gene inactivation, m10-m13 (3months); GRL (Vento-Tormo) to learn multi-omics data analysis, (m18-20) and Alia to learn about the gene editing procedures developed in industry,  m22-24 (2 months).

PhD programme

Ph.D in Immunology and Cell Biology, Aix-Marseille Université (AMU), France.