Lors du congrès SFNano à Montpellier Pauline Chavrier, étudiante en deuxième année de thèse, gagne le prix du meilleur poster pour son travail sur l’étude de l’efficacité de transfection in vitro et la distribution in vivo de liposome ciblant le placenta.
Ci-dessous l’abstract de son travail :
Evaluation of functionalized liposomes’ targeting efficiency by assessing in vitro uptake and in vivo biodistribution
Our team focus on delivering active substance to treat the placenta during pregnancy. Pregnant women are a particular population with specific therapeutic needs. The active substance and its carrier should not be able to cross the placenta, but the delivery should be as specific as possible to avoid off-target effect for the safety of the mother. To this extent, active targeting strategies seem promising when combined with a carrier not able to cross the placenta.
A specific ligand to target the placenta has been identified by our laboratory. It relies on the high affinity of VAR2CSA, a protein found on the surface of erythrocytes infected by the plasmodium falciparum, for the CSA (chondroitin sulfate A), a receptor overexpressed by the placenta. A peptide of 16 amino acid sequence length derived from VAR2CSA sequence was identified thanks to the PEPScan technique.
Liposomes were functionalized with the peptide by optimizing the thiol/maleimide coupling for this specific application. Size and potential zeta were assessed by DLS. After a purification step, the coupling success was monitored by a LC/MS method developed to check the presence of the peptide on the liposomes. Moreover, an indirect quantitative technique by the reaction of fluorescamine and peptides from supernatants enable to determine the coupling efficiency. In vitro internalization and toxicity were evaluated on the BeWo cell line. An improvement of the internalization of the functionalized formulation by a factor 3.5 was found in vitro compared to the control formulation.
After assessing the improvement of the internalization of the functionalized formulation in vitro, the development of methods to evaluate the biodistribution in vivo are needed. Two methods are currently being developed using the fluorescent lipid DOPE-Cy5 in the liposome formulation to assess the biodistribution. Preliminary results were obtained by the acquisition of images by IVIS on ex vivo organs of pregnant mice. The placenta was found to be the second organ with the most signals, right after the liver. A second method using UPLC setting with 2 fluorescent channels is currently being developed, to confirm the results [1].
Pauline Chavrier1, Khair Alhareth1, Louise Fliedel1, Alma Athenas Sánchez-Téllez1,Thierry Fournier 2, Nathalie Mignet1, Karine Andrieux1
1 Unité des Technologies Chimiques et Biologiques pour la Santé (UTCBS), Faculté de pharmacie de Paris, Université de Paris, CNRS UMR8258, INSERM U1267, Paris 75006 2 INSERM, UMR-S1139, Université de Paris, PremUp Foundation 75006 Paris, France
References
[1] Pauline Chavrier et al, Tools to quantify liposomal uptake in vitro and biodistribution in vivo, SFNanoJR 1st seminar on Nanoparticle applications in nucleic acid delivery and imaging (09-06-2023).