A carrier for non-covalent delivery of functional beta-galactosidase and antibodies against amyloid plaques and IgM to the brain.
BACKGROUND
Therapeutic intervention of numerous brain-associated disorders currently remains unrealized due to serious limitations imposed by the blood-brain-barrier (BBB). The BBB generally allows transport of small molecules, typically <600 daltons with high octanol/water partition coefficients, but denies passage to most larger molecules. However, some receptors present on the BBB allow passage of cognate proteins to the brain. Utilizing such receptor-ligand systems, several investigators have developed methods for delivering proteins to the brain, a critical requirement of which involves covalent linking of the target protein to a carrier entity. Such covalent modifications involve extensive preparative and post-preparative chemistry that poses daunting limitations in the context of delivery to any organ. Here, we report creation of a 36-amino acid peptide transporter, which can transport a protein to the brain after routine intravenous injection of the transporter-protein mixture. No covalent linkage of the protein with the transporter is necessary.


METHODS
A peptide transporter comprising sixteen lysine residues and 20 amino acids corresponding to the LDLR-binding domain of apolipoprotein E (ApoE) was synthesized. Transport of beta-galactosidase, IgG, IgM, and antibodies against amyloid plques to the brain upon iv injection of the protein-transporter mixture was evaluated through staining for enzyme activity or micro single photon emission tomography (micro-SPECT) or immunostaining. Effect of the transporter on the integrity of the BBB was also investigated.


RESULTS
The transporter enabled delivery to the mouse brain of functional beta-galactosidase, human IgG and IgM, and two antibodies that labeled brain-associated amyloid beta plaques in a mouse model of Alzheimer's disease.


CONCLUSIONS
The results suggest the transporter is able to transport most or all proteins to the brain without the need for chemically linking the transporter to a protein. Thus, the approach offers an avenue for rapid clinical evaluation of numerous candidate drugs against neurological diseases including cancer. (299 words).
Department of Experimental Pathology, Mayo Clinic, Rochester, Minnesota, USA. sarkar.gobinda@mayo.edu
Gobinda
G
Sarkar
Geoffry L
GL
Curran
Eric
E
Mahlum
Teresa
T
Decklever
Thomas M
TM
Wengenack
Anthony
A
Blahnik
Bridget
B
Hoesley
Val J
VJ
Lowe
Joseph F
JF
Poduslo
Robert B
RB
Jenkins
D000682:Amyloid / Q000276:immunology*; D000818:Animals; D000906:Antibodies / Q000008:administration & dosage*; D001812:Blood-Brain Barrier; D007075:Immunoglobulin M / Q000276:immunology*; D051379:Mice; D015899:Tomography, Emission-Computed, Single-Photon; D001616:beta-Galactosidase / Q000008:administration & dosage*
D000682:Amyloid; D000906:Antibodies; D007075:Immunoglobulin M; D001616:beta-Galactosidase