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• Interspecies differences in the cytochrome P450 activity of hepatocytes exposed to PLGA and silica nanoparticles: an in vitro and in vivo investigation.Cornu R,  Rougier N,  Pellequer Y, Lamprecht A, Hamon P, Li R, Beduneau A, Martin H
  Nanoscale, Mar 2018
  Abstract : Nanomedicines represent a promising approach in the treatment and diagnosis of numerous disorders. The majority of the injected dose of nanoparticles (NPs) is sequestrated in the liver. Despite this hepatic tropism, the interaction of NPs with the detoxification function of the liver remains unclear. The present study consists of evaluating the impact of biodegradable poly(lactide-co-glycolide) (PLGA) and silica NPs on cytochrome P450 (CYP) activities. The effects of NPs were evaluated in vitro on human and rat hepatocytes in primary cultures and in vivo by intravenous injections in healthy rats. More than the physicochemical properties, the composition of NPs (organic, inorganic) dramatically influenced the detoxification function of the liver. Silica NPs modulated the CYP activity both in rat and human hepatocytes, in contrast to PLGA NPs. A CYP isoform-dependent effect was reported and the modulation of the metabolic hepatic activity was species-dependent. Human hepatocytes were sensitive to an exposure to PLGA NPs, whereas no marked effect was detected in rat hepatocytes. The in vitro data obtained in rat hepatocytes were correlated with the in vivo data. This study emphasizes the interest to set up relevant in vitro models using human hepatic cells to evaluate the hepatotoxicity of nanomedicines.
• Reversible opening of the blood-brain barrier by claudin-5-binding variants of Clostridium perfringens enterotoxin's claudin-binding domain.Neuhaus W,  Piontek A,  Protze J,  Eichner M, Mahringer A, Subileau EA, Lee IM, Schulzke JD, Krause G, Piontek J
  Biomaterials, Feb 2018
  Abstract : The blood-brain barrier (BBB) prevents entry of neurotoxic substances but also that of drugs into the brain. Here, the paracellular barrier is formed by tight junctions (TJs) with claudin-5 (Cldn5) being the main sealing constituent. Transient BBB opening by targeting Cldn5 could improve paracellular drug delivery. The non-toxic C-terminal domain of Clostridium perfringens enterotoxin (cCPE) binds to a subset of claudins, e.g., Cldn3, -4. Structure-based mutagenesis was used to generate Cldn5-binding variants (cCPE-Y306W/S313H and cCPE-N218Q/Y306W/S313H). These cCPE-variants were tested for transient TJ opening using multiple in vitro BBB models: Primary porcine brain endothelial cells, coculture of primary rat brain endothelial cells with astrocytes and mouse cerebEND cells. cCPE-Y306W/S313H and cCPE-N218Q/Y306W/S313H but neither cCPE-wt nor cCPE-Y306A/L315A (not binding to claudins) decreased transendothelial electrical resistance in a concentration-dependent and reversible manner. Furthermore, permeability of carboxyfluorescein (with size of CNS drugs) was increased. cCPE-Y306W/S313H but neither cCPE-wt nor cCPE-Y306A/L315A bound to Cldn5-expressing brain endothelial cells. However, freeze-fracture EM showed that cCPE-Y306W/S313H did not cause drastic TJ breakdown. In sum, Cldn5-binding cCPE-variants enabled mild and transient opening of brain endothelial TJs. Using reliable in vitro BBB models, the results demonstrate that cCPE-based biologics designed to bind Cldn5 improve paracellular drug delivery across the BBB.
• Direct and quantitative evaluation of the major human CYP contribution (fmCYP) to drug clearance using the in vitro Silensomes? model.Parmentier Y,  Pothier C,  Hewitt N,  Vincent L, Caradec F, Liu J, Lin F, Trancart MM, Guillet F, Bouaita B, Chesne C, Walther B
  Xenobiotica, Jan 2018
  Abstract : 1. We have applied the concept of using MBIs to produce CYP-Silensomes to quantify the contribution of the major CYPs to drug metabolism (fmCYP). 2. The target CYPs were extensively and selectivity inhibited by the selected MBIs, while non-target CYPs were inhibited by less than 20% of the homologous control activities. Only CYP2D6-Silensomes exhibited a CYP2B6 inhibition that could be easily and efficiently encountered by subtracting the fmCYP2B6 measured using CYP2B6-Silensomes to adjust the fmCYP2D6. 3. To validate the use of a panel of 6 CYP-Silensomes, we showed that the fmCYP values of mono- and multi-CYP metabolised drugs were well predicted, with 70% within ± 15% accuracy. Moreover, the correlation with observed fmCYP values was higher than that for rhCYPs which were run in parallel using the same drugs (