Periodontitis is a highly prevalent, chronic inflammatory disease of the periodontium, leading to the destruction of the tooth supporting tissues and finally tooth loss. Microorganisms in the patients’ periodontal pockets produce molecules, which directly attack the host tissue, and/or cause an immune response leading to tissue destruction. Periodontitis is the main cause for tooth loss in adults: 47% of the US adults have mild, moderate or severe periodontitis (64% of the population > 65 years). The treatment of periodontitis is highly challenging, since drug partitioning into the periodontal pockets is not very pronounced and gingival fluid flow rapidly eliminates the drug from the site of action. Hence, using conventional administration routes, high systemic drug levels are required, while the drug concentration at the target site remains low. This leads to potentially severe side effects and low therapeutic efficacy, despite the availability of highly potent drugs able to act against the pathogenic flora and inflammation. These hurdles can be overcome using local controlled drug delivery systems: In this case, the drug is directly administered at the site of action and its release is controlled during prolonged periods of time. Different types of systems have been proposed; however most of them contain antibiotic drugs and exhibit insufficient adhesion to the walls of the periodontal pockets, combined with inappropriate mechanical properties. This leads to uncontrolled expulsion of at least parts of the systems during the treatment and, thus, unreliable drug exposure to the target site. The aim of this project is to overcome these severe bottlenecks and to develop innovative in-situ forming implants, which: (i) are easy to inject (as liquid formulations), (ii) readily spread within the patients’ pockets and adapt their geometry and size to the individuals’ needs, (iii) exhibit reliable residence times due to improved bioadhesion and adequate plasticity, and (iv) control the release of non-antibiotic drugs during optimized periods of time. The basic idea is to dissolve the drug (or a combination of drugs) together with a biodegradable matrix former in a common solvent. This liquid is administered using standard syringes into the patients’ pockets. Once in contact with aqueous body fluids, the solvent diffuses out of the system, causing the precipitation of the matrix former and drug entrapment. The latter is subsequently released in time-controlled manner at the target site. This leads to optimized therapeutic efficacy and reduced drug exposure to the rest of the human body, thus, minimized side effects. Due to the biodegradability of the in-situ formed implant, empty remnants do not need to be removed after drug exhaust. A highly interdisciplinary consortium encompassing pharmacists, dentists, microbiologists, immunologists, physicists, chemists etc., offers the whole range of innovation: from clinical expertise to advanced research, through technological development, up to cutting-edge evaluation in animal models. New types of in-situ forming implants will be prepared and thoroughly characterized in vitro as well as in vivo (periodontitis mouse model). For instance, MS imaging (MALDI) will allow getting deeper insight into the underlying mass transport mechanisms, drug release kinetics and pharmacodynamic efficacy of the systems, mapping for example the spatial distribution of the drug and inflammation markers in the animal tissue. The obtained comprehensive database on the performance and key features of the innovative drug delivery systems will serve as a basis for the conduction of clinical trials, which are envisaged as follow-up studies. With a French SME being part of the consortium, also the economic exploitation of the results is foreseen. Importantly, non-antibiotic drugs will be studied, thus, the project will contribute to the combat against the development of bacterial resistances.

Antibodies (Abs) exert their function by binding to distinct Fc receptors and complement. The affinity of these interactions is traditionally ascribed to the Ab isotype. At least for the IgGs this view is evolving. N-linked glycans are increasingly proposed to influence binding to the classical Fc-gamma receptors (Fc?R) and allow for binding to non-classical type II receptors. This proposal will study the functional significance of Fc-glycosylation in potentiating or regulating the chronic inflammatory response in Multiple Sclerosis (MS) and its animal models. MS is a chronic disabling disease during which inflammatory lesions in the central nervous system cause local tissue damage, including demyelination and neuronal (axonal) loss. The genetic susceptibility points to a causal role for the immune response, but the triggers that provoke T and B cells to attack myelin, the factors that cause disease relapses, and the anatomical localisation and composition of the inflammatory lesions in relation to the heterogeneous clinical expression of MS remain active fields of investigation. Antibodies contribute to MS. Their presence in the cerebrospinal fluid is a diagnostic hallmark. Active lesions contain antibodies and reveal complement activation. Autoantibodies recognising potassium channel KIR4.1, Neurofascin, as well as glycolipids have been identified. Within MS lesions antibodies specific for Myelin oligodendrocyte glycoprotein (MOG) can be detected. The pathogenicity of MOG Abs is raising attention as their titers are increased in juvenile MS, but also optic neuritis, and in a subset of patients with Neuromyelitis Optica (NMO). The crystallisable fragment (Fc) of Abs binds to distinct Fc receptors (FcRs) and complement. For human IgGs this tightly regulated process relies on the structural heterogeneity of the Ig-Fc domain that arises from differences among the four subclasses (IgG1, IgG2, IgG3 and IgG4), and the complex bi-antennary N-linked glycan attached to the conserved Asn297. The glycosylation of the Fc-domain is proposed to create two structural conformations, an “open” conformation that favors binding to type I FcR that include the activating receptors Fc?RIA (CD64), Fc?RIIA (CD32a), Fc?RIIC, Fc?RIIIA (CD16a) and Fc?RIIIB, as well as the inhibitory receptor Fc?RIIB (CD32b). Accordingly, the absence of sialic acids and low levels of galactosylation confer important pro-inflammatory properties to IgG by facilitating their binding to activating Fc?Rs. In addition, the absence of core-fucose improves the affinity to the Fc?IIIA, thereby enhancing antibody-dependent cellular cytotoxicity. In contrast, a “closed” conformation favours binding to type II FcRs that comprise the C-type lectin receptor CD209 (DC-SIGN) and CD23. These sialylated Abs are endowed with a potential anti-inflammatory effect. The overarching aim of this research project is to assess whether this diversity of Fc-effector functions impacts on the severity of chronic inflammatory diseases of the central nervous system. Our strategy is to study this impact functionally using a translational approach. In MS patients we will analyse the N-glycome and the Fc-glycome of the antibody response. In animal models of MS we will study the pathogenicity of Fc-glycovariants.

Advanced Glycation End-products (AGEs), notably carboxymethyl-lysine (CML), are involved in age-related diseases and found at high levels in several processed foods. The exposure to dietary AGES, particularly in critical developmental periods but also throughout life, raises questions about their harmfulness to health, specifically their role in low-grade inflammation, inflammaging and age-related disorders The aim of this collaborative project is to understand by which biological mechanisms perinatal or lifelong exposure to dietary CML contributes to the induction of chronic, low-grade inflammation and the occurrence of related chronic diseases. The novelty of this study lies in its interdisciplinary examination of the molecular mechanisms underlying the deleterious effects of CML, and its testing of antagonists that block the CML-mediated cellular response via RAGE, the receptor for AGEs. Our strategy is to use transgenic mice, C elegans and cellular models in order to fully elucidate the mechanisms by which CML acts in vivo (the CML–RAGE axis), and to develop a new anti inflammaging drug.

Deoxynivalenol (DON), a mycotoxin produced by Fusarium species, is a frequent contaminant of grains and cereal products worldwide. DON causes many toxic effects on growth, immune response, reproduction, development… At the intestinal level, DON has been demonstrated to affect key immune functions which could lead to the induction and/or persistence of intestinal diseases. The potential link between DON exposure and human Inflammatory Bowel Diseases (IBD) is the global aim of this proposal. Indeed, the different actors participating to the pathophysiological process leading to IBD development are still not well understood. We hypothesize that an improper detoxification of DON, implicating gut microflora and/or endogenous enzymes, would lead to an increased susceptibility to DON toxicity in IBD patients. The objectives of this proposal are to compare, in healthy and IBD suffering individuals: 1) the cartography of DON absorption, distribution, metabolism and excretion; 2) the detoxification of DON by the gut and the consequences in term of immune homeostasis of DON exposure ; 3) the effects of DON on the gut microbiota composition and the reciprocal effect of the gut microbiota on DON metabolism studied in vitro. The study of consequences of oral subchronic exposure of DON in humanized gnotobiotic mice colonized with a healthy or an IBD patient microbiota is our fourth objective. Our proposal is interdisciplinary bringing together gastroenterologists and researchers on nutrition, risk assessment, pathophysiology and microbiology.