Uptake and transport of B 12 -conjugated nanoparticles in airway epithelium

Abstract

Non-invasive delivery of biotherapeutics, as an attractive alternative to injections, could potentially be achieved through the mucosal surfaces, utilizing nanoscale therapeutic carriers. However, nanoparticles do not readily cross the mucosal barriers, with the epithelium presenting a major barrier to their translocation. The transcytotic pathway of vitamin B12 has previously been shown to ‘ferry’ B12-decorated nanoparticles across intestinal epithelial (Caco-2) cells. However, such studies have not been reported for the airway epithelium. Furthermore, the presence in the airways of the cell machinery responsible for transepithelial trafficking of B12 is not widely reported. Using a combination of molecular biology and immunostaining techniques, our work demonstrates that the bronchial cell line, Calu-3, expresses the B12-intrinsic factor receptor, the transcobalamin II receptor and the transcobalamin II carrier protein. Importantly, the work showed that sub-200 nm model nanoparticles chemically conjugated to B12 were internalised and transported across the Calu-3 cell layers, with B12 conjugation not only enhancing cell uptake and transepithelial transport, but also influencing intracellular trafficking. Our work therefore demonstrates that the B12 endocytotic apparatus is not only present in this airway model, but also transports ligand-conjugated nanoparticles across polarised epithelial cells, indicating potential for B12-mediated delivery of nanoscale carriers of biotherapeutics across the airways.

Time and cell‐dependent effects of endocytosis inhibitors on the internalization of biomolecule markers and nanomaterials

“…Nanoparticles based on polystyrene have been extensively studied in many cell lines with and without attached targeting ligands for their effects on viability and apoptosis, and also in terms of their internalization pathways. (Fowler et al, ; Fowler et al, ; Milani et al, ; Varela et al, ) The polystyrene nanoparticles were also similar in zeta potentials, with values of −37.7 mV for the 50 nm nanoparticles and ‐ 34.2 mV for the 100 nm NPs, and thus were expected to be colloidally stable but not to vary in uptake via a charge‐dependent mechanism.…”

Synthetic Approaches toward Vitamin B12 Conjugates

“…Moreover, (CN)Cbl was functionalized with precursors that can serve as chelating agents for metals,, e. g. for manganese (conjugate 28 g ) or 89 Zr (conjugate 28 h ) complexes . Additionally, this carbamate methodology has facilitated the attachment of vitamin B 12 to nanoparticles ,,…”

The role of albumin receptors in regulation of albumin homeostasis: Implications for drug delivery

“…They are primarily expressed in polarized epithelial cells with a few exceptions. For instance, cubilin has been identified in several types of cells from different species, including epithelial cells from proximal tubules (rat [153], dog [59], mice and humans [150]), yolk sac (rat [153] and human [165]), small intestine (canine [166], rabbit [167], dog [168] and rat [163]), glomerular podocytes (rat and human [169]), inner ear (rat [170]), lung (human [171]), gallbladder (human [172]), mammary (murine and human [173]), uterus and oviduct (human [174]) as well as placental syncytiotrophoblasts and cytotrophoblasts (human [165]). In most cases, cubilin is co-expressed with megalin, where both are located at the apical membranes [167,[175][176][177].…”