Method of enhancing proliferation and/or hematopoietic differentiation of stem cells

Abstract

The present invention provides a method for enhancing the proliferation and/or hematopoietic differentiation and/or maintenance of mammalian stem cells. The method is useful for generating expanded populations of hematopoietic stem cells (HSCs) and thus mature blood cell lineages. This is desirable where a mammal has suffered a decrease in hematopoietic or mature blood cells as a consequence of disease, radiation or chemotherapy. The method of the present invention comprises increasing the intracellular level of a cdx in stem cells, including hematopoietic stem cells, in culture, either by providing an exogenous cdx protein to the cell, or by introduction into the cell of a genetic construct encoding a cdx. The cdx is selected from the cdx family and includes cdx1, cdx2, or cdx4. The cdx may be a wild type protein appropriate for the species from which the cells are derived, or a mutant form of the protein.

1 . A method for enhancing proliferation or hematopoietic differentiation of a mammalian stem cell comprising, transfecting said stem cells in an in vitro culture medium with an exogenous nucleic acid comprising a cdx coding sequence operably linked to a promoter. 
     
     
         2 . The method of  claim 1 , wherein the stem cell is a hematopoietic stem cell. 
     
     
         3 . The method of  claim 1 , wherein the cell is a CD34 +  cell. 
     
     
         4 . The method of  claim 1 , wherein the cell is autologous. 
     
     
         5 . The method of  claim 1 , wherein the cell is obtained from a human. 
     
     
         6 . The method of  claim 5 , wherein the human is suffering from, or is susceptible to, decreased blood cell levels. 
     
     
         7 . The method of  claim 6 , wherein the decreased blood cell levels are caused by chemotherapy, radiation therapy, bone marrow transplantation therapy or congenital anemia. 
     
     
         8 . The method of  claim 1 , wherein the exogenous nucleic acid is a retroviral vector. 
     
     
         9 . The method of  claim 1 , wherein the exogenous nucleic acid is an episomal vector. 
     
     
         10 . The method of  claim 1 , wherein the stem cell is an embryonic stem cell. 
     
     
         11 . The method of  claim 1 , wherein the cdx is selected from the group consisting of cdx 1 and cdx 2. 
     
     
         12 . A method of treating a mammal in need of improved hematopoietic capability, comprising the steps of:
 (a) removing hematopoietic stem cells from the mammal;   (b) transfecting said stem cells with exogenous nucleic acid comprising cdx sequences;   (c) culturing said transfected stem cells to form an expanded population of stem cells; and   (d) returning said expanded cells to the mammal, whereby hematopoietic capability is improved.   
     
     
         13 . The method of  claim 12 , wherein the mammal is a human. 
     
     
         14 . The method of  claim 12 , wherein the exogenous nucleic acid is a retroviral vector. 
     
     
         15 . The method of  claim 12 , wherein the cdx is selected from the group consisting of cdx 1 and cdx 2. 
     
     
         16 . A method for enhancing proliferation or hematopoietic differentiation of a mammalian stem cell comprising, treating said stem cells by addition in an in vitro culture medium of an exogenous cdx peptide. 
     
     
         17 . The method of  claim 16 , wherein the stem cell is a hematopoietic stem cell. 
     
     
         18 . The method of  claim 16 , wherein the cell is a CD34 +  cell. 
     
     
         19 . The method of  claim 16 , wherein the cell is autologous. 
     
     
         20 . The method of  claim 16 , wherein the cell is obtained from a human. 
     
     
         21 . The method of  claim 20 , wherein the human is suffering from, or is susceptible to, decreased blood cell levels. 
     
     
         22 . The method of  claim 21 , wherein the decreased blood cell levels are caused by chemotherapy, radiation therapy, bone marrow transplantation therapy, or congenital anemia. 
     
     
         23 . The method of  claim 16 , wherein the stem cell is an embryonic stem cell. 
     
     
         24 . The method of  claim 16 , wherein said cdx is genetically fused to a transport moiety. 
     
     
         25 . The method of  claim 24 , wherein said transport moiety is a fragment of HIV tat protein. 
     
     
         26 . The method of  claim 16 , wherein the cdx is selected from the group consisting of cdx 1 and cdx 2. 
     
     
         27 . A method of treating a mammal in need of improved hematopoietic capability, comprising the steps of:
 (a) removing hematopoietic stem cells from the mammal;   (b) treating said stem cells by administration of exogenous cdx4 peptide;   (c) culturing said stem cells to form an expanded population of stem cells; and   (d) returning said expanded cells to the mammal, whereby hematopoietic capability is improved.   
     
     
         28 . The method of  claim 27 , wherein the mammal is a human. 
     
     
         29 . The method of  claim 27 , wherein the cdx is selected from the group consisting of cdx 1 and cdx 2.