DS04 - Vie, santé et bien-être

Immune tolerance by IL-34: new biomarker and potential immunotherapy – hIL34-Tol

Immune tolerance by IL-34: new biomarker and potential immunotherapy

Transplantation is the only treatment for patients suffering of a number of diseases but the use of immunosuppressors lead to unwanted side effects with high morbidity and mortality. Therefore, new treatments are needed that will be more specific for anti-donor immune responses or with less side effects. We showed that delivering the cytokine IL-34 could decrease immune responses in human organ transplantation and GVHD and induce tolerance.

The project aim to in depth investigate the tolerogenic effect of IL-34 in human, correlate IL34 expression with transplantation outcome and pave the way to a new clinical trial in transplantation.

The first aim is to define the expression of IL-34 and its receptors (CSF1R, CD138 and PTPz) in normal fluids, cells and tissues and investigate the molecular role of IL-34 on human cells. We demonstrated that in rat, IL-34 can be an immunoregulatory molecule on the effector immune response through differentiation of regulatory macrophages; this role had never been evidenced before and need to be explored in human.<br /><br />The second aim of this proposal is to finely analyse the expression of IL34 in transplanted patients (kidney transplant and bone marrow transplant). This data can reinforce the relevance of IL-34 administration in human and can help stratify a population of patients with deficient IL-34 production.<br /><br />The last aim of this proposal is to develop and test a recombinant molecule, we will generate 2 versions: an IL-34Fc recombinant molecule and an IL-34/anti-IL34 Ab complex. We will test and compare them in vitro and provide proof of concept in vivo of its potential in immune tolerance in transplantation using NSG humanized mice. We have demonstrated in rat using a viral vector that overexpression of IL-34 efficiently inhibit acute cardiac allograft rejection and induces tolerance. This proof of concept has yet to be done in a “human model” and could similarly be used as an immunomodulatory drug.<br /><br />The gathering of these data will provide important clues about the involvement of IL-34 in tolerance and could pave the way to a new clinical trial in transplantation.

We established standard protocols for assessing the activity of IL-34 and other cell subsets. We developed techniques to isolate and culture rare cell populations and developed 13-color flow cytometry panels. Proteins will be produced by providers.
Several aspects of this study involved collaboration. We have access to cohorts of kidney transplanted patients (DIVAT-Biocoll, Nantes) and bone marrow transplanted patients (Hospital. H. Mondor, Paris), to healthy individuals ’blood samples that will be provided by the Etablissement Français du Sang of Nantes. This will guarantee the access to key cohorts available under strict ethical considerations. The project benefit from outstanding research environment - in and outside Nantes .
To test the protective effect of IL-34 in vivo, in collaboration with the humanized rodents platform, we will use an immune humanized mice model and apply treatment. Immunodeficient mice that are engrafted with human functional cells are ideal preclinical models to investigate human immune responses in an in vivo setting. We will use 2 models: skin allotransplantation and GVHD that are ideal settings to assess the potential regulatory properties of IL-34 in vivo.
Humanized mice GVL model: In collaboration, we have obtained tumor cell line that will be transplanted into immunodeficient NSG mice and that she has demonstrated are rejected by human PBMCs.

The expected results of the project are:
-to characterize the expression profile of IL-34 and its receptors (CD115, CD138 and PTPz) in human cells, fluids and tissues of healthy individuals
-to demonstrate the effect of IL-34 on human macrophages and DCs
-to identify the role of IL-34 secretion by human Tregs and characterize IL-34-deficient Tregs
-to demonstrate that IL-34 levels correlate with transplant outcome and graft rejection score in kidney transplantation and can serve as biomarkers
-to demonstrate that IL-34 levels correlate with occurrence of acute GVHD in bone marrow transplantation and can serve as biomarkers
-to prove the role of IL-34 in a model of transplantation in humanized mice
-to demonstrate the benefit of a Fc fusion or cytokine/Ab complex formation to improve the in vitro and in vivo effect of IL-34.

At short/mid-term (10 years), the project will help patients by 1) developing a new treatment for subpopulation categories for whom there is no treatment available, 2) enabling patients to have a better quality of life by avoiding heavy side effects usually associated with high doses traditional treatments, extending patients life expectancy.
This proposal will lead to higher efficacy and safety in the patient treatment compared to standard treatment schemes, and, in this way, to a more appropriate treatment for these patients.
Therefore, beyond technology, this proposal could have a strong societal impact by potentially bringing a new standard of care and thus revolutionizing the patient management in, on the short/mid-term, four medical conditions with high unmet needs (organ transplant and GvHD), and, on the longer term, potentially a much wider range of inflammatory diseases.

This project has already allowed the filing of a new patent in January 2019 protecting different forms of IL-34. The success of this project will lead to the creation of a start-up and the licensing of associated patents by the new company. This start-up will take IL-34 to a Phase 1 clinical trial in healthy volunteers.

Transplantation is the only treatment for patients suffering of a number of diseases. The use of immunosuppressors in organ transplantation has allowed remarkable success in the short and medium term graft survival, but unwanted side effects still lead to high morbidity and mortality, even when avoiding excessive immunosuppression. In the long term, immunosuppressors have not really prolong allograft survival and can even be deleterious in the establishment of tolerance. Therefore, new treatments are needed that will be more specific for anti-donor immune responses or with less side effects and that would allow at least to decrease the use of immunosuppressors. Cytokines and enzymes controlling metabolic pathways have been described as powerful tools for controlling immune responses and it is important to identify new mediators of immune tolerance. Interleukin-34 (IL-34) is a cytokine, described for the first time in 2008. Although IL-34 shared very little homology with M-CSF (CSF1), they share a common receptor (CSF1R) and IL-34 has also 2 distinct receptors, protein-tyrosine-phosphatase zeta (PTPz) and CD138 (syndecan-1). Until now, studies have demonstrated that this cytokine is released by some tissues and involved in the differentiation and survival of macrophages, monocytes and DC in response to inflammation. More recent articles (for review in Guillonneau et al., 2017) including our own work have described the immunoregulatory properties of IL-34. We have demonstrated that IL-34 is secreted by Foxp3+ CD4+ and CD8+ Treg in human and CD8+CD45RClow Tregs in rat. We also demonstrated that blockade of IL-34 in vitro in human and rat MLR assays inhibited both CD4+ and CD8+ Treg suppressive function. Most importantly, we also showed that IL-34 treatment in vivo in a model of cardiac allograft induced transplant tolerance through induction and differentiation of macrophages toward a M2-type regulatory profile and subsequent induction of CD4+ and CD8+ Tregs by these M2-type macrophages. Thus, our results published in 2015 are the first ones to describe tolerance in organ transplantation with IL-34. Therefore, delivering IL-34 could decrease immune responses in human organ transplantation and GVHD. Furthermore, these results are the basis of an international patent deposition (WO2016009041) claiming the use of IL-34 in these therapeutic domains.
The overall objective of the project “hIL34-Tol” aims at developing a breakthrough scientific approach in Immunotherapy that could address large unmet medical needs in transplantation. The scientific approach is based on the tolerogenic effect of a new cytokine, IL-34.
The gathering of these data will provide important clues on the mechanism of action of IL-34 in in human and whether IL-34 plays a crucial role in immune tolerance. This study will pave the way to a new clinical trial in transplantation.

Project coordination

Carole GUILLONNEAU (Centre pour la recherche en transplantation & immunointervention)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CRTI Centre pour la recherche en transplantation & immunointervention

Help of the ANR 316,656 euros
Beginning and duration of the scientific project: September 2017 - 36 Months

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