Project

Discipline

Celiac disease; Drug delivery; Enzymes; Bioadhesion; Imaging

Lead
Lay summary
Celiac disease (CD) is an inflammatory disease of the intestine nutritional deficiencies, osteoporosis, secondary autoimmune disorders, malignancies). Hence, there is an urgent need for complementary non-dietary therapies to help treating this common disorder (~1% of the population). CD is induced by immunogenic sequences of gluten proteins which are highly resistant to human digestive proteases. One of the most interesting therapeutic options consists in administering to CD patients exogenous enzymes (“glutenases”) that cleave and detoxify the gluten peptides. While promising, this approach is in part limited by the relative e.g., triggered in genetically predisposed individuals by the ingestion of gluten and gluten-like proteins of wheat, rye, and barley. There is increased morbidity and mortality associated with CD. The current and only treatment is life-long elimination of gluten from the diet. This dietary restriction is a difficult experience for many patients and is often associated with a decreased quality of life. Poor compliance, whether inadvertent or voluntary, to a strict gluten-free diet is frequent and predisposes patients to CD complications (instability of the enzymes in the harsh conditions encountered in the GI tract. The objective of this research is increase the stability and efficacy of glutenases through polymer conjugation. In parallel, we will develop imaging tools to monitor in real time the glutenase activity in the GI tract. We believe CD patients would be better controlled if their daily diet could tolerate minimal amounts of gluten and therefore there is an urgent need for new therapeutic and/or adjuvant modalities.

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Last update: 21.02.2013

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Celiac disease (CD) is an inflammatory enteropathy triggered in genetically predisposed individuals by the ingestion of gluten and gluten-like proteins of wheat, rye, and barley. There is increased morbidity and mortality associated with CD. The current and only treatment is life-long elimination of gluten from the diet. This dietary restriction is a difficult experience for many patients and is often associated with a decreased quality of life. Poor compliance, whether inadvertent or voluntary, to a strict gluten-free diet is frequent and predisposes patients to CD complications (e.g., nutritional deficiencies, osteoporosis, secondary autoimmune disorders, malignancies). Hence, there is an urgent need for complementary non-dietary therapies to help treating this common disorder (~1% of the population). CD is induced by immunogenic sequences of gluten proteins which are highly resistant to human digestive proteases. In the gastro-intestinal (GI) tract, a fraction of these peptides reaches the lamina propria, causing a T-cell mediated immune response. One of the most interesting therapeutic options consists in administering to CD patients exogenous enzymes (“glutenases”) that cleave and detoxify the gluten peptides. While promising, this approach is in part limited by the relative lability of the enzymes in the harsh conditions encountered in the GI tract. We believe that conjugation of appropriate polymers to glutenases would be a viable strategy to improve their stability in the stomach and intestine and therefore enhance their efficacy. To validate this hypothesis we have defined the following objectives.1. Characterize the activity and stability of several glutenases under simulated GI conditionsDespite the large number of glutenases described in the literature, there have been very few studies comparing head-to-head the GI stability of these enzymes. We plan to perform such experiments in order to rank glutenase activity under simulated GI conditions, and identify the most stable candidates. These experiments will give us some information about the inactivation process of the enzymes and therefore help establishing the most appropriate stabilization strategies.2. Develop a fluorescence imaging method to study in real time the enzymatic activity in vivoAn important objective of this research is to develop an in vivo fluorescent-based assay that will allow the in situ monitoring of the glutenase activity in real time and help establishing in vitro-in vivo correlations. The assay will rely on the increase in fluorescence intensity that will occur upon the cleavage of labelled immunogenic-like peptide sequences. 3. Synthesize and characterize polymer-conjugated glutenasesBased on the route of inactivation of the glutenases, the enzymes will be modified with polymers to improve their stability. Polymers with diverse structures and functionalities will also be screened to introduce mucoadhesive properties, which could increase the residence time of the conjugates in the upper part of the GI tract. This approach could prove valuable for glutenases that are less active at higher pH or rapidly inactivated by bile salts or intestinal enzymes.4. Study the stability and bioadhesion of the polymer-conjugated glutenases in the GI tractConjugated glutenases showing improved GI resistance in vitro will be evaluated in rats for their bioadhesive properties and ability to degrade specific immunogenic sequences of gluten. The polymer-enzyme transit in the GI tract and the in vivo enzymatic activity will be monitored by in vivo fluorescence imaging techniques.5. Evaluate the efficacy of the polymer-conjugated glutenases in a mouse model of gluten sensitivityThe last step of this work will aim at demonstrating that polymer-conjugated glutenases are better detoxifying agents than their native counterparts. Only in vivo experiments assessing the impact of the treatment on the immune response and effects on the intestinal mucosa can establish whether polymer conjugation is a viable option to improve the therapeutic efficacy of glutenases. These experiments will be performed on a mouse model of gluten-sensitivity.