Klotho fusion protein and uses thereof

The present inventors have designed fusion proteins comprising the sequence of three known chronokines —sKL, sTREM2, and TIMP2—, which provides synergistic anti-aging effects compared to the use of the free chronokines. As shown in the Examples below, seeking to improve the therapeutic efficacy of known chronokines, the present inventors have devised fusion proteins with strong anti-aging effects. Surprisingly, the inventors found that by fusing the proteins sKL, sTREM2, and TIMP2 into a single chimeric protein, their individual activities were synergistically increased (see, for example, Figure 5 and Figure 6). Moreover, from the data provided below in an animal model of Alzheimer's disease, it is apparent that the fusion proteins of the invention can be used as a medicament for treating age-related human diseases, in particular neurodegenerative diseases (see Figure 7). Thus, in a first aspect, the invention provides a fusion protein comprising (i) sTREM2 or a functional variant thereof; (ii) TIMP2 or a functional variant thereof; and (iii) sKL or a functional variant thereof. In a second aspect, the invention provides a polynucleotide that encodes the fusion protein as defined in the first aspect. In a third aspect, the invention provides an expression vector comprising the polynucleotide as defined in the second aspect. In a fourth aspect, the invention provides a host cell comprising the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, or the expression vector as defined in the third aspect. In a fifth aspect, the invention provides a cell culture comprising the host cell as defined in the fourth aspect. In a sixth aspect, the invention provides a pharmaceutical composition comprising a therapeutically effective amount of the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, or the host cell as defined in the fourth aspect, with at least one pharmaceutically acceptable excipient, diluent, or carrier. In a seventh aspect, the invention provides a kit of parts comprising the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect, and instructions for its use. In an eighth aspect, the invention provides the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect, for use a medicament. In a nineth aspect, the invention provides the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect, for use in the prevention or treatment of an age-related disease or disorder; particularly an age-related neurodegenerative disease or disorder. This aspect can also be formulated as the use of the fusion protein, polynucleotide, expression vector, or host cell of the invention for the manufacture of a medicament for the prevention or treatment of an age-related disease or disorder; particularly an age-related neurodegenerative disease or disorder. This aspect can also be formulated as a method for the prevention or treatment of an age-related disease or disorder, particularly an age-related neurodegenerative disease or disorder, the method comprising administering a therapeutically effective amount of the fusion protein, polynucleotide, expression vector, or host cell of the invention together with at least one pharmaceutically acceptable excipient, diluent, or carrier to a subject in need thereof. In a tenth aspect, the invention provides a process for the production of a fusion protein as defined in the first aspect, the process comprising (i) culturing the host cell as defined in the fourth aspect; or, alternatively, (ii) in vitro transcription and/or translation of the polynucleotide as defined in the second aspect. In an eleventh aspect, the invention provides the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect, for use in extending the lifespan of a subject. In a further aspect, the invention provides a non-therapeutic method for extending the lifespan of a subject, the method comprising administering to a subject the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect. And in a further aspect, the invention provides the use of the fusion protein as defined in the first aspect, the polynucleotide as defined in the second aspect, the expression vector as defined in the third aspect, the host cell as defined in the fourth aspect, or the pharmaceutical composition as defined in the sixth aspect, for extending the lifespan of a subject.