Equipe d’Accueil : institut IMAGINE U1163
Intitulé de l’Unité : Laboratory of cellular and molecular mechanisms of hematological
disorders and therapeutic implications, U 1163, Inserm, institut Imagine, Paris.
Nom du Responsable de l’Unité : Pr Olivier HERMINE
Nom du Responsable de l’Équipe : Dr Coralie BLOCH
Adresse : Institut IMAGINE, 25 bd Montparnasse 75015 Paris
Responsable de l’encadrement : Dr C BLOCH
Tél : ………0620171726……………… Fax : ……………………… E-mail: ………………………Résumé du projet
The hemophagocytic syndrome1 is a cytokines-dependent hyper-inflammatory state leading to tissue lysis by activated non-malignant macrophages2. An exome sequencing of an adult patient (and her parents) with an autoinflammatory disease (« Still disease ») complicated by a severe3 HLH syndrome, identified a rare variant (790G>A, G264R) in a gene, « ERAP-1 ». No abnormalities were found in genes classically associated with HLH or autoinflammatory diseases (Polyweb Imagine panel). ERAP-1 is a ubiquitous, zinc-dependent aminopeptidase expressed in the endoplasmic reticulum (ER)4. Its peptidase function allows the trimming of peptide precursors to generate antigens for MHC I molecules to be presented to CD8 and NK cells5. Further studies on ERAP1 KO mouse models show that ERAP1 is involved in modulating cytokine responses of macrophages by expressing more inflammatory cytokines, more signalling molecules (MYD-88), and specific
recognition receptors, particularly certain TLRs (TLR 6, 2, 4, …)6. Moreover, the phagocytic activity of macrophages from ERAP1 KO mice is significantly reduced7. ERAP1 is expressed at the ER and may be retained by the ER protein 44 (ERp44)8, but there may also be an extracellular expression of ERAP1, which is important for inflammatory and phagocytic functions9. Extracellular variants of ERAP1 in culture with human PBMCs modify cytokine synthesis similarly to specific ERAP1 inhibitors10. This extracellular expression might be endosome-dependent11. We already established: (1) A defect in the production of pro-inflammatory cytokines by the patient’s PBMCs when stimulated by LPS. (2) An increased production of pro-inflammatory cytokines by the patient’s PBMCs when stimulated by IL-1ß. (3) A specific inhibitor of ERAP1 (Thimerosal, a specific inhibitor) specifically reproduces the LPS response defect observed in the patient. (4) An extracellular exosomes dependant expression of ERAP1 following LPS stimulation.
We hypothesise:
(1) ERAP1 functions as a key mediator of innate immune responses through TLR-dependent
signalling and enhancement of phagocytosis in human macrophages.
(2) ERAP1 genetic variants may be pathogenic, driving the dysregulated inflammatory cascade
characteristic of HLH in genetically susceptible individuals and may thus act as a modifier gene.
M2 internship SKILLS:
1. ERAP1 involvement in cytokine production. Pro-inflammatory cytokine kinetics production under several TLR kinetics stimulations will be tested using enzyme-linked immunosorbent assays (ELISA) with multiple cytokine-specific antibodies.
2. ERAP1 dynamics and cellular localisation. To characterise the dynamic localisation of ERAP1 in response to various stimuli, examining both intracellular and extracellular compartments. This can be investigated using FACS approaches.
3. ERAP1 functions in phagocytosis and exosome involvement. Whether ERAP1-mediated enhancement of phagocytosis is dependent on exosome-based mechanisms.
MATERIALS:
• THP-1 pre-monocytic wild-type (THP1-ERAP1WT), Genetically modified into ERAP1 deficient cell lines (THP1-ERAP1KO) and into THP-1 knock-in cells harbouring the disease-associated ERAP1 G264R variant (THP1-ERAP1Kin G264R), (obtained by CRISPR/cas9 (Genoway company, France), production in progress).
• ERAP1-specific pharmacological inhibitors, developed by the Pasteur Institute of Lille.
Bibliographie :
1. Ménasché G, et al. Immunol Rev 2005;203:165–79.
2. Cron RQ, et all. Annu Rev Med 2023;74:321–37.
3. Bloch C, et al. J Allergy Clin Immunol 2024;153(1):256–64.
4. Saric T, et al. Nat Immunol 2002;3(12):1169–76.
5. Chang S-C, et al. Proc Natl Acad Sci U S A 2005;102(47):17107–12.
6. Aldhamen YA, and al. PLoS One 2013;8(7):e69539.
7. Blake MK et al.. 2022;23(1):9.
8. Hisatsune, 2015, Molecular Cell 58 (6): 1015–27.
9. Goto Y, Tsujimoto M. J Immunol 2014;192(9):4443–52.
10. Aldhamen YA, et al. J Innate Immun 2015;7(3):275–89.
11. Goto Y et al. Biochim Biophys Acta Mol Cell Res 2018;1865(6):874–88.
Dernières Publications en lien avec le projet :
1 The IL-10/IL-6 Ratio and the Risk Score: Two Cytokines-Based Predictors for Malignancy- Associated Hemophagocytic Lymphohistiocytosis in Adults (M-HLHa). Bloch C, Am J Hematol. 2026 Jun 16.
2-Severe adult hemophagocytic lymphohistiocytosis (HLHa) correlates with HLH-related gene variants. Bloch C, J Allergy Clin Immunol. 2024 Jan;153(1):256-264.
Ce projet s’inscrit dans une possibilité de poursuite en thèse
type de financement prévu : Bourse d’Ecole doctorale, bourse FRM, bourse Imagine (médecin), poste d’accueil INSERM.