Bi-Specific Therapeutic Proteins for Tissue Repair

A method of protecting tissue from damage, the method comprising:

• (a) providing a bi-specific protein having (1) an activator domain, wherein the activator domain comprises a variant of human insulin-like growth factor IGF-1 comprising one or more mutations, wherein the one or more mutations consist of a substitution at one or more positions corresponding to E3, Y24, Y31, Y60, and combinations thereof, and (2) a targeting domain, wherein the targeting domain comprises a variant of human Annexin A5 comprising one or more mutations, wherein the one or more mutations consist of a substitution at the position corresponding to C316 and optionally at one or more positions corresponding to R63, K70, K101, E138, D139, N160 and combinations thereof;
• and
• (b) administering to a patient in need thereof a therapeutically effective amount of the bi-specific protein whereby the Annexin A5 variant targets the bi-specific protein to a first cell of the tissue, wherein the cell expresses phosphatidylserine on the outer leaflet of the plasma membrane, and whereby upon exposure of the IGF-1 variant to an IGF-1 receptor at the surface of a second cell, the IGF-1 variant specifically activates the IGF-1 receptor so as to protect tissue from damage.

A method of inhibiting apoptosis, the method comprising:

• (a) providing a bi-specific protein having (1) an activator domain, wherein the activator domain comprises a variant of human insulin-like growth factor IGF-1 comprising one or more mutations, wherein the one or more mutations consist of a substitution at one or more positions corresponding to E3, Y24, Y31, Y60, and combinations thereof, and (2) a targeting domain, wherein the targeting domain comprises a variant of human Annexin A5 comprising one or more mutations, wherein the one or more mutations consist of a substitution at the position corresponding to C316 and optionally at one or more positions corresponding to R63, K70, K101, E138, D139, N160 and combinations thereof;
• and
• (b) administering to a patient in need thereof a therapeutically effective amount of the bi-specific protein whereby the Annexin A5 variant targets the bi-specific protein to a first cell of the tissue, wherein the cell expresses phosphatidylserine on the outer leaflet of the plasma membrane, and whereby upon exposure of the IGF-1 variant to an IGF-1 receptor at the surface of a second cell, the IGF-1 variant specifically activates the IGF-1 receptor so as to inhibit apoptosis.

A method of promoting cell survival, the method comprising:

• (a) providing a bi-specific protein having (1) an activator domain, wherein the activator domain comprises a variant of human insulin-like growth factor IGF-1 comprising one or more mutations, wherein the one or more mutations consist of a substitution at one or more positions corresponding to E3, Y24, Y31, Y60, and combinations thereof, and (2) a targeting domain, wherein the targeting domain comprises a variant of human Annexin A5 comprising one or more mutations, wherein the one or more mutations consist of a substitution at the position corresponding to C316 and optionally at one or more positions corresponding to R63, K70, K101, E138, D139, N160 and combinations thereof;
• and
• (b) administering to a patient in need thereof a therapeutically effective amount of the bi-specific protein whereby the Annexin A5 variant targets the bi-specific protein to a first cell of the tissue, wherein the cell expresses phosphatidylserine on the outer leaflet of the plasma membrane, and whereby upon exposure of the IGF-1 variant to an IGF-1 receptor at the surface of a second cell, the IGF-1 variant specifically activates the IGF-1 receptor so as to promote cell survival.