Staff member

Maximilian Loeck

PhD Student
Targeted therapeutics and nanodevices
+34 934 035 280
Staff member publications

Muntimadugu, Eameema, Silva-Abreu, Marcelle, Vives, Guillem, Loeck, Maximilian, Pham, Vy, del Moral, Maria, Solomon, Melani, Muro, Silvia, (2022). Comparison between Nanoparticle Encapsulation and Surface Loading for Lysosomal Enzyme Replacement Therapy International Journal Of Molecular Sciences 23, 4034

Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) enhance the delivery of therapeutic enzymes for replacement therapy of lysosomal storage disorders. Previous studies examined NPs encapsulating or coated with enzymes, but these formulations have never been compared. We examined this using hyaluronidase (HAse), deficient in mucopolysaccharidosis IX, and acid sphingomyelinase (ASM), deficient in types A–B Niemann–Pick disease. Initial screening of size, PDI, ζ potential, and loading resulted in the selection of the Lactel II co-polymer vs. Lactel I or Resomer, and Pluronic F68 surfactant vs. PVA or DMAB. Enzyme input and addition of carrier protein were evaluated, rendering NPs having, e.g., 181 nm diameter, 0.15 PDI, −36 mV ζ potential, and 538 HAse molecules encapsulated per NP. Similar NPs were coated with enzyme, which reduced loading (e.g., 292 HAse molecules/NP). NPs were coated with targeting antibodies (> 122 molecules/NP), lyophilized for storage without alterations, and acceptably stable at physiological conditions. NPs were internalized, trafficked to lysosomes, released active enzyme at lysosomal conditions, and targeted both peripheral organs and the brain after i.v. administration in mice. While both formulations enhanced enzyme delivery compared to free enzyme, encapsulating NPs surpassed coated counterparts (18.4- vs. 4.3-fold enhancement in cells and 6.2- vs. 3-fold enhancement in brains), providing guidance for future applications.

Manthe, Rachel L., Loeck, Maximilian, Bhowmick, Tridib, Solomon, Melani, Muro, Silvia, (2020). Intertwined mechanisms define transport of anti-ICAM nanocarriers across the endothelium and brain delivery of a therapeutic enzyme Journal of Controlled Release 324, 181-193

The interaction of drug delivery systems with tissues is key for their application. An example is drug carriers targeted to endothelial barriers, which can be transported to intra-endothelial compartments (lysosomes) or transcellularly released at the tissue side (transcytosis). Although carrier targeting valency influences this process, the mechanism is unknown. We studied this using polymer nanocarriers (NCs) targeted to intercellular adhesion molecule-1 (ICAM-1), an endothelial-surface glycoprotein whose expression is increased in pathologies characterized by inflammation. A bell-shaped relationship was found between NC targeting valency and the rate of transcytosis, where high and low NC valencies rendered less efficient transcytosis rates than an intermediate valency formulation. In contrast, an inverted bell-shape relationship was found for NC valency and lysosomal trafficking rates. Data suggested a model where NC valency plays an opposing role in the two sub-processes involved in transcytosis: NC binding-uptake depended directly on valency and exocytosis-detachment was inversely related to this parameter. This is because the greater the avidity of the NC-receptor interaction the more efficient uptake becomes, but NC-receptor detachment post-transport is more compromised. Cleavage of the receptor at the basolateral side of endothelial cells facilitated NC transcytosis, likely by helping NC detachment post-transport. Since transcytosis encompasses both sets of events, the full process finds an optimum at the intersection of these inverted relationships, explaining the bell-shaped behavior. NCs also trafficked to lysosomes from the apical side and, additionally, from the basolateral side in the case of high valency NCs which are slower at detaching from the receptor. This explains the opposite behavior of NC valency for transcytosis vs. lysosomal transport. Anti-ICAM NCs were verified to traffic into the brain after intravenous injection in mice, and both cellular and in vivo data showed that intermediate valency NCs resulted in higher delivery of a therapeutic enzyme, acid sphingomyelinase, required for types A and B Niemann-Pick disease.

Keywords: Blood-brain barrier, ICAM-1-targeted nanocarriers, Targeting valency, Receptor-mediated transport, Lysosomal transcytosis destinations