Brain-penetrating IgG-iduronate 2-sulfatase fusion protein for the mouse.

Abstract

Mucopolysaccharidosis (MPS) type II (Hunter's syndrome) is caused by mutations in the iduronate 2-sulfatase (IDS) fusion protein. MPS-II affects the brain, and enzyme replacement therapy is not effective in the brain, because the enzyme does not cross the blood-brain barrier. To treat mouse models of MPS-II with brain-penetrating IDS, the lysosomal enzyme was reengineered as an IgG-IDS fusion protein. The mature human IDS was fused to the carboxyl terminus of both heavy chains of the chimeric monoclonal antibody (MAb) against the mouse transferrin receptor (TfR), and the fusion protein is designated cTfRMAb-IDS. The purity and identity of the fusion protein was confirmed by electrophoresis and Western blotting with antibodies to mouse IgG and human IDS. The EC₅₀ of binding of the cTfRMAb-IDS fusion protein to the mouse TfR (0.85 ± 0.15 nM) was comparable to the EC₅₀ of binding of the cTfRMAb (0.78 ± 0.05 nM). The IDS enzyme activity of the cTfRMAb-IDS fusion protein was 126 ± 1 nmol · h⁻¹ · μg⁻¹ protein. After intravenous injection in the mouse, the cTfRMAb-IDS fusion protein was rapidly removed from plasma and distributed to tissues, including brain and spinal cord. The uptake of the fusion protein by brain or spinal cord was 1.3 ± 0.1 and 2.2 ± 0.2% injected dose/g, respectively, which is 100-fold greater than the brain uptake of IDS alone. This work shows that a lysosomal sulfatase can be reengineered as an IgG-enzyme fusion protein that rapidly penetrates the brain after intravenous administration.

• Authors: Qing-Hui Zhou, Ruben J Boado, Jeff Zhiqiang Lu, Eric Ka-Wai Hui, William M Pardridge
• Journal: Drug metabolism and disposition: the biological fate of chemicals (Drug Metab Dispos) Vol. 40 Issue 2 Pg. 329-35 (Feb 2012) ISSN: 1521-009X [Electronic] United States
• PMID: 22065691 (Publication Type: Journal Article)

Chemical References

• Antibodies, Monoclonal
• Glycoproteins
• IDS protein, human
• Immunoglobulin G
• Receptors, Transferrin
• Recombinant Fusion Proteins
• Tfrc protein, mouse
• Oxidoreductases Acting on Sulfur Group Donors
• SUMF1 protein, human
• Sulfatases

Topics

• Animals
• Antibodies, Monoclonal (genetics, metabolism)
• Antibody Affinity
• Blood-Brain Barrier (metabolism)
• Brain (metabolism)
• Drug Design
• Genetic Vectors
• Glycoproteins (genetics, metabolism)
• Humans
• Immunoglobulin G (genetics, metabolism)
• Kinetics
• Male
• Mice
• Mice, Inbred C57BL
• Oxidoreductases Acting on Sulfur Group Donors
• Permeability
• Protein Engineering
• Receptors, Transferrin (antagonists & inhibitors, metabolism)
• Recombinant Fusion Proteins (blood, metabolism, pharmacokinetics)
• Spinal Cord (metabolism)
• Sulfatases (genetics, metabolism)
• Tissue Distribution