Jean Yves Springael

Our research

Chemokine receptors signaling in physiological and pathological processes

Chemokines are small basic proteins that control the release of innate immune cells from the bone marrow during homeostasis as well as in response to infection and inflammation. They mediate their effect by binding to cell surface receptors, which belong to the large family of G protein-coupled receptors (GPCRs). Receptor binding initiates a cascade of intracellular events leading to chemotaxis and the regulation of a wide range of other functions, which vary according to the cell population. About forty chemokines and more than twenty chemokine receptors have been identified so far. Chemokine receptors constitute an attractive family of drug targets in the frame of inflammatory diseases, AIDS or cancer. However, the development of therapeutic compounds up to the clinic has been hampered by the complexity of the chemokine system. There is therefore a need for a better comprehension of the chemokine system.

1. Chemokine receptors selectivity
The chemokine system is described as redundant and promiscuous, with a single chemokine ligand binding to different receptors and a single receptor having several ligands. However, these past few years, a new paradigm has emerged in the field of GPCRs, assuming that receptors can activate differentially selective signaling pathways according to the specific conformation stabilized by the bound ligand. Differences in ligand responses may occur through differential activation of G proteins or differential recruitment of scaffolding proteins, like arrestins or PDZ-proteins. This concept is of particular interest to fully appreciate the nature of chemokine receptors signaling. By using a combination of functional assays, we are studying signaling bias amongst chemokines acting on the same receptor. We are also investigating the putative biased nature of synthetic small molecules and already demonstrated that molecules acknowledged as “selective antagonists” can also act as full agonist, partial agonist or antagonist according to the nature of the receptor, the enantiomer considered or the signaling pathway investigated.

The classification of ligands or drugs targeting chemokine receptors, and GPCRs in general, as blockers or agonists often relies on the use of a restricted number of functional assays, leaving unaddressed their protean nature. Revisiting properties of some of these molecules could therefore unveil unexpected biased signaling, with putative influence on their use in vivo.

2. Oligomeric assembly of chemokine receptors and allosteric regulation
Chemokine receptors, like many GPCRs, can also form homo- or hetero-oligomers. There is therefore a need for a better understanding of how chemokine receptors are organized and regulated at the supramolecular level in the plasma membrane of leukocytes, and how this organization affects the activity of agonists or antagonists of these receptors and the subsequent intracellular signaling network. Using various assays, we showed that chemokine receptors form homo- and hetero-oligomers in living cells. Heteromerization of some receptors in leukocytes resulted in a strong negative binding cooperativity of allosteric nature, indicating that chemokines have a dual function: they are agonists of their cognate receptor and allosteric modulators of cognate receptor partners. Heteromerization also impacts on drugs properties. We showed that antagonists of therapeutically important receptors can inhibit allosterically the function of other receptors on which they do not bind directly, with important implications on the effects of these agents in vivo. Collectively, our studies indicate that besides their canonical role in signaling, chemokine receptors can also act as allosteric modulator of one another through receptor oligomerization.
We are currently investigating the role of receptor oligomerization in physiological and pathological processes. By using B cell development in mice as a model system, we recently unveiled a novel role of CCR7 as selective allosteric modulator of CXCR4 function. By using CCR7 KO mice, we showed that the upregulation of CCR7 expression occurring in late stages of B cell development contributes to the functional inhibition of CXCR4 signals important for B cell egress to specific bone marrow niches. Besides, we are also investigating whether the upregulation of some chemokine receptors occurring in the frame of inflammation or cancer modulate the function of other receptors expressed on immune cells.

The fact that chemokine receptors function in vivo depends on their oligomerization status adds thus a new dimension to our understanding of how these receptors might control cell behavior in physiological and pathological processes.

3. BRET-based assays
To monitor receptor oligomerization and signalling activity, we developed and used various Bioluminescence Resonance Energy Transfer (BRET)-based assays. BRET measures the transfer of energy between a luminescent donor (Renilla luciferase; Rluc) and a fluorescent acceptor (a green fluorescent protein; GFP).

Group members

Team:

Jean Yves Springael, PI (jyspring@ulb.ac.be)

phone # +32(0) 2 555 4198

PhD Students:

  • Degroot Gaetan-Nagim
  • Corbisier Jenny

Publications

Selected publications:
1. Corbisier, J., Galès, C., Huszagh, A., Parmentier M. and Springael J.Y. Partial agonist and biased signaling properties of the synthetic enantiomers J113863/UCB35625 at chemokine receptors CCR2 and CCR5. J. Biol. Chem. (2017) 292: 575-584.

2. De henau, O., Degroot, G.N., Imbault, V., Robert, V., De Poorter, C., Mcheik, S., Galés, C., Parmentier, M. and Springael, J.Y. Signaling properties of chemerin receptors CMKLR1, GPR1 and CCRL2 PLoSONE (2016) 11: :e0164179.

3. Corbisier, J., Galès, C., Huszagh, A., Parmentier M. and Springael J.Y. Biased signaling at chemokine receptors J. Biol. Chem. (2015) 290: 9542-9554.

4. De poorter, C., Bartsoen, K, Lannoy, V., Parmentier, M. and Springael J.Y. Consequences of ChemR23 heteromerization with chemokines receptors CXCR4 and CCR7 PLoSONE (2013) 8: e58075.

5. Sohy D., Yano, H., de Nadai, P, Urizar, E., Guillabert A., Javitch, J.A., Parmentier, M. and Springael, J.Y. Hetero-oligomerization of CCR2, CCR5, CXCR4 and the protean effects of “selective”-antagonists J. Biol. Chem., (2009) 284: 31270-31279

6. Springael, J.Y., Urizar E. Costagliola, S, Parmentier, M. and Vassart G. Allosteric properties of G-protein coupled receptor (GPCR) oligomers. Pharmacology and Therapeutics (2007) 115:410-418

7. Sohy,D., Parmentier,M., and Springael,J.Y. Allosteric transinhibition by specific antagonists in CCR2/CXCR4 heterodimers. J. Biol. Chem., (2007).282: 30062-30069.

8. Springael, J.Y., Le Minh, P. N., Urizar E., Costagliola, S., Vassart, G. and Parmentier, M. Allosteric modulation of binding properties between units of chemokine receptor homo- and hetero-oligomers. Mol. Pharmacol. (2006) 69:1652-61

9. Springael, J.Y., Urizar E. and Parmentier, M. Dimerization of chemokine receptors and its functional consequences. Cytokine Growth Factor Rev. (2005) 16: 611-623.

10. El-Asmar, L., Springael, J.Y., Ballet, S., Urizar, E., Vassart, G. and Parmentier, M., Evidence for negative binding cooperativity within CCR5-CCR2b heterodimers. Mol. Pharmacol. (2005) 67: 460-469