Generation and Characterization of an Abcc1 Humanized Mouse Model (hABCC1) with Knockout Capability

Abstract

ATP-binding cassette (ABC) transporters such as ABCB1 (Pglycoprotein), ABCC1 (MRP1), and ABCG2 (BCRP) are well known for their role in rendering cancer cells resistant to chemotherapy. Additionally, recent research provided evidence that, along with other ABC transporters (ABCA1 and ABCA7), they might be cornerstones to tackle neurodegenerative diseases. Overcoming chemoresistance in cancer, understanding drug-drug interactions, and developing efficient and specific drugs that alter ABC transporter function are hindered by a lack of in vivo research models, which are fully predictive for humans. Hence, the humanization of ABC transporters in mice has become a major focus in pharmaceutical and neurodegenerative research. Here, we present a characterization of the first Abcc1 humanized mouse line. To preserve endogenous expression profiles, we chose to generate a knockin mouse model that leads to the expression of a chimeric protein that is fully human except for one amino acid. We found robust mRNA and protein expression within all major organs analyzed (brain, lung, spleen, and kidney). Furthermore, we demonstrate the functionality of the expressed human ABCC1 protein in brain and lungs using functional positron emission tomography imaging in vivo. Through the introduction of loxP sites, we additionally enabled this humanized mouse model for highly sophisticated studies involving cell type-specific transporter ablation. Based on our data, the presented mouse model appears to be a promising tool for the investigation of cell-specific ABCC1 function. It can provide a new basis for better translation of preclinical research.

Strategies to gain novel Alzheimer’s disease diagnostics and therapeutics using modulators of ABCA transporters

“…Our group has previously established a humanized ABCC1 mouse model, 543 and an ABCA7 model is under characterization. Here, we generated knock-in mouse models producing a chimeric protein that is completely human except for one amino acid.…”

“…Here, we generated knock-in mouse models producing a chimeric protein that is completely human except for one amino acid. 543 In addition, as this gene was flanked by loxP sites, this humanized model can be knocked out in specific cell populations and at a specific age. 543 Models such as these represent the future of pre-clinical drug candidate evaluation.…”

“… 543 In addition, as this gene was flanked by loxP sites, this humanized model can be knocked out in specific cell populations and at a specific age. 543 Models such as these represent the future of pre-clinical drug candidate evaluation.…”

ABC Transporters at the Blood–Brain Interfaces, Their Study Models, and Drug Delivery Implications in Gliomas

“…It is important to remember that there can be molecular and physiological differences between species, such as expression levels, substrate specificity, and transport efficiency in the case of ABC transporters (see Section 3.6). Therefore, models with humanized ABC transporters, as P-gp and BCRP, have been developed to better represent drug transport in humans [236][237][238][239]. Diverse techniques are used to evaluate the permeability of molecules into the brain and their clearance and obtain important ADME, toxicity, and PK-PD parameters (reviewed in [5,6,8,133,240].…”

Use of PET Imaging to Assess the Efficacy of Thiethylperazine to Stimulate Cerebral MRP1 Transport Activity in Wild-Type and APP/PS1-21 Mice

“…Positron emission tomography (PET) imaging with 6-bromo-7-[ 11 C]methylpurine ([ 11 C]BMP) has been used to measure the activity of MRP1 in the brain and lungs of mice and rats [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. [ 11 C]BMP itself is not transported by MRP1 but is in vivo rapidly and quantitatively converted by cytosolic glutathione- S -transferases into the corresponding glutathione conjugate S-(6-(7-[ 11 C]methylpurinyl)) glutathione ([ 11 C]MPG), which is a substrate of MRP1 [ 9 ].…”