Lectin-derived progenitor cell preservation factors and methods of use

Abstract

The invention relates to an isolated nucleic acid molecule that encodes a protein that is effective to preserve progenitor cells, such as hematopoietic progenitor cells. The nucleic acid comprises a sequence defined by SEQ ID NO:1, a homolog thereof, or a fragment thereof. The encoded protein has an amino acid sequence that comprises a sequence defined by SEQ ID NO:2, a homolog thereof, or a fragment thereof that contains an amino acid sequence TNNVLQVT. Methods of using the encoded protein for preserving progenitor cells in vitro, ex vivo, and in vivo are also described. The invention, therefore, include methods such as myeloablation therapies for cancer treatment wherein myeloid reconstitution is facilitated by means of the specified protein. Other therapeutic utilities are also enabled through the invention, for example, expanding progenitor cell populations ex vivo to increase chances of engraftation, improving conditions for transporting and storing progenitor cells, and facilitating gene therapy to treat and cure a broad range of life-threatening hematologic diseases.

Description

BACKGROUND OF THE INVENTION [0001] The invention relates to a nucleic acid and its corresponding protein for use in connection with the preservation of progenitor cells. More specifically, the invention relates to a nucleic acid and the protein that it encodes and which is capable of preserving progenitor cells, as well as a method of using the protein for preserving progenitor cells. [0002] Each day the bone marrow generates and releases into the circulation several billion fully-differentiated, functional blood cells. Production of these cells derives from a small stock of quiescent progenitor cells (including the most primitive stem cells and other less primitive but still immature progenitors) by a process called hematopoiesis (Zipori 1992). The most primitive stem cells have the capacity to generate >1013 cells containing all blood lineages (Turhan et al. 1989). The production of such a large number of cells is achieved by extensive proliferation coupled with successive diff...

AI Technical Summary

Benefits of technology

[0087] It is a further advantage of the invention that it enables preservation of cells for periods and under conditions that permit shipment of cells, e.g., by mail, to distant locations for transplantation.

[0088] The recombinant protein also enables ex vivo manipulation of hematopoietic progenitor cells for use in gene therapy by preserving cells in liquid culture. For example, by preserving hematopoietic progenitor cells in culture for more than two weeks, the protein enables increased targeting efficiency by viral vectors that enter non-replicating cells (e.g., vectors such as adeno-associated viruses), and provides longer periods for the evaluation of the resultant cell populations to determine efficiency of transfection. Thus, in another embodiment, the method can be used in conjunction with methods of transfecting an exogenous DNA sequence into somatic cells. The method can then include transfecting progenitor cells selectively preserved by the recombinant protein.

[0089] The invention also has utility in conjunction with therapies, e.g., cancer therapies, which employ irradiation. Specifically, because the recombinant protein preserves progenitor cells in a quiescent state, administration of the recombinant protein to a mammalian subject in vivo allows the use of increased levels of total body irradiation to eliminate neoplastic cells, while leaving quiescent cells relatively unaffected. The protein can be employed in conjunction with other cytoprotective substances such as IL-1 to obtain an enhanced or complementary effect.

[0090] Thus, the method can involve treating a mammalian subject in need of hematopoietic therapy. In particular, the recombinant protein can be used to improve hematopoietic competence in a mammal, i.e., the mammal's ability to generate functional mature blood elements. For example, a tissue sample including hematopoietic progenitor cells can be obtained from the subject. Then the tissue sample can be cultured ex vivo in a growth medium containing the recombinant protein to preserve the progenitors, while allowing cycling cells to proliferate, differentiate and die. The cultured cells become significantly enriched in the primitive progenitor cells. Meanwhile, the mammal can be subjected to

Problems solved by technology

Soluble regulators and cell-cell interactions mediate differentiation pathways of immature progenitors through a tightly-controlled but inadequately understood process.

No known cytokines alone or in combination can preserve viability of primitive progenitors in liquid culture without stromal support beyond a few days.

While the use of stromal cell culture has heretofore proven to be useful for the maintenance of hematopoietic stems cells in the laboratory setting, such approaches are not easily amenable to clinical application.

Isolating and establishing stromal cell cultures for individual patients is not practical either because of time constraints o

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