Use Of Transferrin Receptor Research Articles

Mechanisms of TfR-mediated transcytosis and sorting in epithelial cells and applications toward drug delivery

Transferrin receptor has been an important protein for many of the advances made in understanding the intricacies of the intramolecular sorting pathways of endocytosed molecules. The unique internalization and recycling functions of transferrin receptor have also made it an attractive choice for drug targeting and delivery of large protein-based therapeutics and toxins. Recent advances in elucidating the role of the intracellular controllers of transferrin recycling and sorting, such as Rab proteins and their effectors, have led to enhancement of transferrin receptor as a drug delivery vehicle. This review focuses on the use of transferrin receptor as an agent for facilitating drug delivery and targeting, and the role that mechanisms of transferrin receptor sorting and transcytosis play in these events.

Iron-deficiency anemia is associated with high concentrations of transferrin receptor in serum

We evaluated the use of transferrin receptor (TfR) in serum as an index of iron deficiency in 19 patients diagnosed as having iron-deficiency anemia, in 17 patients with anemia of chronic disease, and in a control group of 19 nonanemic patients who underwent elective ocular or nasopharyngeal surgery. The assessment of iron status of the anemic patients was based on the presence of stainable iron on bone marrow examination. In the patients with iron-deficiency anemia, the serum TfR concentration was 5.3 +/- 1.8 mg/L (mean +/- SD), significantly higher than in the control group (1.7 +/- 0.5 mg/L) or in the patients with anemia of chronic disease (1.6 +/- 0.4 mg/L). This study suggests that serum TfR measurement is a reliable index of iron depletion and potentially of importance in the diagnosis of iron-deficiency anemia.

トランスフェリン・レセプターの新しい精製方法とその生化学的性質

An improved method for the purification of human placental transferrin receptor (Tf-R) was developed. Fresh human placenta was homogenized in cold acetone and the acetone powder was prepared. After the acetone powder had been washed with HEPES buffer, the insoluble proteins containing Tf-R were separated by centrifugation and dissolved in Emulgen 109P-containing buffer. Tf-R was collected by affinity binding to Tf-Sepharose and extracted by consecutive treatment with 4 different kinds of buffers. Tf-R was eluted by buffer C (2 M KCl) and buffer D (0.5 M NaSCN). Tf-R was characterized as a 90-kDa monomer on gradient SDS-PAGE (4-20%) in the presence of 2-mercaptoethanol. Though there were several minor bands of 180- and above 205-kDa, all these bands were confirmed as Tf-R by Western blotting using an anti-Tf-R monoclonal antibody (OKT 9). The apparent molecular weights, measured by HPLC using a TSK-G 3,000 SW column, demonstrated that Tf-Rs eluted with buffer C were approximately 370-, 500- and above 500-kDa, but only a peak of above 500-kDa was found in Tf-R eluted with buffer D. Although the polymers of Tf-R with molecular weight of above 500-kDa were resistant to trypsin digestion, the Tf-R of 370-kDa was resistant to the enzyme only when it conjugated to the diferric Tf. The stability of the polymers of above 500-kDa to trypsin digestion suggested an advantage for the repeated use of Tf-R in the endocytosis of diferric Tf, which was performed by the translocation of Tf-R between cell surface and intracellular vesicles.