Blood–Brain Barrier Transport Platform: Humanized in vivo systems for evaluating receptor-mediated CNS delivery strategies

While receptor binding affinity is important, brain exposure is shaped by multiple additional factors, including receptor expression levels, endothelial trafficking pathways, intracellular sorting, receptor recycling, vascular architecture, and systemic pharmacokinetics. Peripheral tissue expression of the targeted receptor and downstream biodistribution can also influence exposure profiles. In disease settings, alterations in BBB integrity, inflammation, and vascular function may further affect transport behavior. Evaluating BBB transport therefore requires systems capable of integrating receptor biology with pharmacokinetic and tissue-level context.

Transferrin Receptor 1 (TfR1) is a transmembrane protein involved in cellular iron uptake and is expressed on brain endothelial cells at the blood–brain barrier. Because TfR1 undergoes receptor-mediated endocytosis, it has been widely explored as a target for CNS delivery strategies designed to leverage RMT. TfR1-based approaches are commonly studied across advanced therapeutic modalities to support evaluation of brain exposure, biodistribution, and translational delivery concepts under physiologically relevant conditions.

CD98hc-mediated transport and TfR1-mediated transport represent distinct RMT pathways with differing receptor biology, expression patterns, and intracellular trafficking characteristics. These differences may influence transport kinetics, brain exposure profiles, and peripheral biodistribution. As a result, CD98hc has emerged as an additional pathway of interest alongside TfR1 for CNS delivery research. Comparative evaluation of these pathways in vivo can support informed selection of transport strategies aligned with specific program goals and modality architectures.

Comparing multiple RMT pathways allows researchers to evaluate how differences in receptor biology, trafficking behavior, and systemic expression influence CNS delivery performance. Because no single RMT pathway is universally optimal across all therapeutic modalities, in vivo comparison can inform decisions related to affinity tuning, valency design, dosing strategies, and translational risk. Dual-pathway and pathway-comparison systems enable head-to-head evaluation within a controlled physiological and genetic context, supporting more informed program-level decisions.

Disease states such as neurodegeneration, neuroinflammation, vascular dysfunction, and aging may alter BBB integrity, receptor expression, and intracellular transport processes. These changes can influence brain penetration, regional biodistribution, and exposure dynamics of receptor-mediated delivery strategies. Evaluating BBB transport within disease-relevant in vivo models may therefore provide additional insight into translational behavior and therapeutic response that is not fully captured in healthy systems alone.

Humanized BBB transport models are in vivo systems in which key transport receptors have been genetically engineered to express their human counterparts under endogenous regulatory control. These models are designed to support evaluation of human-specific receptor interactions, transport biology, and translational pharmacokinetics. By enabling assessment of CNS delivery strategies in a physiologically relevant context, humanized models can help reduce uncertainty associated with species differences and support more informed translational decision-making during CNS drug development.

Yes. Taconic supports cross‑breeding of customer‑owned or externally developed models with our humanized TfR1 and CD98hc lines to enable evaluation of CNS delivery strategies within your specific disease or biological context.

When cross‑breeding is performed at Taconic as part of a Colony Management Solutions program, Taconic waives all license fees associated with the use of our humanized models, simplifying project execution and reducing administrative burden.

In addition to model access, Taconic provides scientific consultation, breeding strategy design, and colony management support to help ensure successful integration of RMT biology into your program.