Bioactive fish collagen peptides weaken intestinal inflammation by orienting colonic macrophages phenotype through mannose receptor activation.

PURPOSE: Particular interest is now given to the potential of dietary supplements as alternative non-pharmacological approaches in intestinal inflammation handling. In this aim, this study evaluates the efficiency of fish collagen peptides, Naticol®Gut, on colonic inflammation. METHODS: Wild type and Mannose receptor-deficient in the myeloid lineage C57BL/6 mice were administered with Dextran Sodium Sulfate (DSS), Naticol®Gut, DSS, and Naticol®Gut or only water for 4 or 8 days. Inflammatory status was evaluated by establishing macroscopic and microscopic scores, by measuring cytokine and calprotectin production by ELISA and the myeloperoxidase activity by chemiluminescence. Colonic macrophages were phenotyped by measuring mRNA levels of specific markers of inflammation and oxidative status. Colonic immune populations and T-cell activation profiles were determined by flow cytometry. Mucosa-associated gut microbiota assessment was undertaken by qPCR. The phenotype of human blood monocytes from inflammatory bowel disease (IBD) subjects was characterized by RT-qPCR and flow cytometry and their oxidative activity by chemiluminescence. RESULTS: Naticol®Gut-treated DSS mice showed attenuated colonic inflammation compared to mice that were only exposed to DSS. Naticol®Gut activity was displayed through its ability to orient the polarization of colonic macrophage towards an anti-inflammatory and anti-oxidant phenotype after its recognition by the mannose receptor. Subsequently, Naticol®Gut delivery modulated CD4 T cells in favor of a Th2 response and dampened CD8 T-cell activation. This immunomodulation resulted in an intestinal eubiosis. In human monocytes from IBD subjects, the treatment with Naticol®Gut also restored an anti-inflammatory and anti-oxidant phenotype. CONCLUSION: Naticol®Gut acts as a protective agent against colitis appearing as a new functional food and an innovative and complementary approach in gut health.

Synthesis of versatile chemical tools toward a structure/properties relationships study onto targeting colloids.

As part of a drug delivery project, four aldehydes of the type Pam-Lys(Pam)-spacer-CO-CHO were synthesized to be included in targeting colloids. Though amphiphilic, they were obtained within reasonable yields (18-55%) and with high RP-HPLC purity ( approximately 90%). Parallely, six complementary targeting peptides of the type H(2)N-NH-CH(2)-CO-spacer-YGRGDSP-NH(2) were prepared to be anchored onto colloids. Isolated yields are related to the spacer length and nature. To easily and rapidly modulate the distance between the peptide and the vesicle, every partners were elaborated on solid phase and the expected constructions were obtained by hydrazone ligation. One possible application is presented here with multilamellar vesicles targeting HUVEC cells. Preliminary results prove that the fine-tuning of the spacer length permits to optimize the recognition toward the target cells.

Synthesis and preliminary physical applications of a rhodamin-biotin phosphatidylethanolamine, an easy attainable lipid double probe.

In route to a physical study aimed at understanding lipids and proteins sorting in cells, we designed a rhodamin-labelled biotinylated phosphatidylethanolamine (PE), as a useful and easy-attainable lipid double probe. The target compound was successfully engaged in preliminary physical experiments.

Cooperative extraction of membrane nanotubes by molecular motors.

In eukaryotic cells, nanotubes represent a substantial fraction of transport intermediates between organelles. They are extracted from membranes by molecular motors walking along microtubules. We previously showed that kinesins fixed on giant unilamellar vesicles in contact with microtubules are sufficient to form nanotubes in vitro. Motors were attached to the membrane through beads, thus facilitating cooperative effects. Koster et al. proposed that motors could dynamically cluster at the tip of tubes when they are individually attached to the membrane. We demonstrate, in a recently designed experimental system, the existence of an accumulation of motors allowing tube extraction. We determine the motor density along a tube by using fluorescence intensity measurements. We also perform a theoretical analysis describing the dynamics of motors and tube growth. The only adjustable parameter is the motor binding rate onto microtubules, which we measure to be 4.7 +/- 2.4 s(-1). In addition, we quantitatively determine, for a given membrane tension, the existence of a threshold in motor density on the vesicle above which nanotubes can be formed. We find that the number of motors pulling a tube can range from four at threshold to a few tens away from it. The threshold in motor density (or in membrane tension at constant motor density) could be important for the understanding of membrane traffic regulation in cells.

Fluorouracil prodrugs for the treatment of proliferative vitreoretinopathy: formulation in silicone oil and in vitro release of fluorouracil.

Three new N(1)-alkylcarbonyl-5-fluorouracil derivatives that are prodrugs of 5-fluorouracil (FU), one of them being a co-drug FU-retinoic acid (RA), were studied as potentially effective drugs against postsurgical proliferative vitreoretinopathy (PVR). The stability of N(1)-octenoylFU (3), N(1)-lauroylFU (2), and N(1)-retinoylFU (4) in aqueous medium, their solubility in silicone oil (SiO), the kinetics of FU release in an in vitro system were determined. Compound 3 is very rapidly soluble in SiO. Its saturation concentration, reached after 6h, is 233 +/- 13 microg g(-1) SiO. Compound 2 is not very soluble in SiO but its kinetic of solubilization is fast. Its saturation concentration, reached after 2 days, is 27 +/- 2 microg g(-1) SiO. Compound 4 is poorly soluble in SiO. A concentration plateau, with a mean value of 4 microg g(-1) SiO, is reached after 4 days. The addition in SiO of 5% of a perfluorinated perhydrogenated alkene greatly improves the solubilization of compound 4. Two different types of FU release are observed. For compound 3, the release is fast and is achieved after 1 day. For compounds 2 and 4, the release is slower and is ended at 10 and 27 days, respectively. The solubility of the prodrugs in SiO is not correlated with their lipophilicity, whereas the release rate of FU decreased with increased lipophilicity of the prodrug. The most promising prodrug is compound 4 that slowly releases two active drugs (FU and RA) with a t (1/2 release) of 5.8 days. It might be interesting for the treatment of PVR. However, an in vivo study on an animal model of PVR is necessary to prove the efficacy of this formulation and to study its toxicity.