Methods and compositions for expanding long-term hematopoietic stem cell populations

Abstract

The invention generally features compositions and methods for expanding long term hematopoietic stem cells (HSCs) in a population of cells. In particular, the invention relates to a method of expanding long term HSCs by culturing an initial population of HSCs with macrophages that promote self-renewal of long term HSCs. The expanded cell population provides a source of cells for therapeutic treatments utilizing HSC transplantation.

1 . A therapeutic composition comprising ex vivo expanded long term hematopoietic stem cells (HSCs), wherein obtained HSCs were co-cultured with M2 polarized macrophages and optionally at least one macrophage-derived secretion factor thereby generating the ex vivo expanded long term HSCs, wherein the HSCs have improved expansion and engraftment capabilities compared to HSCs expanded with non-polarized macrophages. 
     
     
         3 . The therapeutic composition of  claim 1 , wherein the ex vivo expanded long term HSCs comprise a substantially pure population of long-term HSCs. 
     
     
         4 . The therapeutic composition of  claim 1 , wherein the HSCs are obtained from the group consisting of bone marrow, peripheral blood, cord blood, blood, placental tissue, tissue, and combinations thereof. 
     
     
         5 . The therapeutic composition of  claim 1 , wherein the HSCs are differentiated from isolated cells selected from the group consisting of embryonic stem cells, adult stem cells, induced pluripotent stem cells, stem cells transdifferentiated from other cell types, and combinations thereof. 
     
     
         6 . The therapeutic composition of  claim 1 , wherein the macrophages are isolated from blood, cord blood, bone marrow, spleen, peritoneal cavity, and combinations thereof. 
     
     
         9 . The therapeutic composition of  claim 1 , wherein the expanded long term HSCs are cryopreserved in a cryopreservation medium. 
     
     
         10 . A kit comprising:
 a) a starter population of HSCs   b) M2 polarized macrophages and optionally at least one macrophage-derived secretion factor; and   c) a container.   
     
     
         11 . The therapeutic composition of  claim 1 , wherein the HSCs are resuspended in a pharmaceutically acceptable medium suitable for administration to a recipient subject. 
     
     
         12 . The therapeutic composition of  claim 1 , wherein the HSCs are incorporated into a sterile injectable solution.