Polypeptides having brain-localizing activity and uses thereof
The present invention relates to polypeptides having a brain-localizing activity, molecules comprising these polypeptides, and pharmaceutical agents that confer brain-localizing activity. The present inventors are the first to reveal amino acid motif sequences involved in brain-localizing activity. Polypeptides that comprise such motif sequences and have brain localizing activity were discovered as follows: DNAs encoding polypeptides comprising random amino acid sequences were synthesized, and incorporated into a phage library. The phage library produced was used to screen for polypeptides having brain-localized activity, which yielded such several polypeptides. These polypeptides comprised common sequences, which lead to the successful discovery of amino acid motif sequences involved in brain-localizing activity. The polypeptides of the present invention comprising the motif sequences specifically bind to cerebrovascular endothelial cells, and induce a transcellular pathway that enables brain-specific targeting and transport of substances in the cerebral parenchyma, which was not possible prior to the present invention.
1. An isolated polypeptide comprising:
(a) a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12; or
(b) a polypeptide comprising a peptide region cyclized by a disulfide bond formed between cysteine residues on both ends of the polypeptide of (a).
2. The polypeptide of claim 1 , wherein the length of the polypeptide is 9 amino acids or less.
3. A pharmaceutical agent for conferring brain-localizing activity to an arbitrary molecule, wherein the agent comprises the polypeptide of claim 1 .
4. The pharmaceutical agent of claim 3 , wherein the arbitrary molecule is an arbitrary polypeptide.
5. A molecule having brain-localizing activity, wherein the molecule comprises the polypeptide of claim 1 .
6. The molecule of claim 5 , wherein the molecule is a phage particle or a coat protein of a phage particle.
7. The molecule of claim 5 , wherein the molecule is a fusion protein formed with an isolated polypeptide of any one of (a) to (b) described below:
(a) a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12; and
(b) a polypeptide comprising a peptide region cyclized by a disulfide bond formed between cysteine residues on both ends of the polypeptide of (a).
8. A carrier for delivery to the brain, wherein the carrier comprises the polypeptide of claim 1 .
9. A carrier for delivery to the brain, wherein the carrier comprises a structure in which the polypeptide of claim 1 is bound to a micelle, liposome, or microcapsule.
10. A therapeutic agent for brain disease, wherein the agent comprises a structure in which a drug is supported by the carrier of claim 8 .
11. A method for producing a molecule having brain-localizing activity, wherein the method comprises binding to an arbitrary molecule a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12.
12. A method for translocating an arbitrary molecule into the brain of an animal, wherein the method comprises the steps of:
(a) producing a molecule having brain-localizing activity, wherein the molecule comprises a structure in which an arbitrary molecule is bound to a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12; and
(b) administering the molecule into the body of the animal.
13. A method of screening for a molecule having binding activity to a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12, wherein the method comprises the steps of:
(a) contacting with a test molecule a polypeptide comprising any one of the amino acid sequences set forth in SEQ ID NOs: 1 and 3 to 12;
(b) detecting binding activity between the polypeptide and the test molecule; and
(c) selecting a molecule that binds to the polypeptide.
14. A therapeutic agent for brain disease, wherein the agent comprises a structure in which a drug is supported by the carrier of claim 9 .