METHODS FOR EXPANDING HEMATOPOIETIC STEM CELLS USING REVITALIZED MESENCHYMAL STEM CELLS

1 - 39 . (canceled)

40 . A method for preparing a revitalized mesenchymal stem cell (MSC) comprising:

culturing a mesenchymal stem cell (MSC); and

transducing the MSC with one or more vector(s), the vector(s) encoding at least one of the following genes: Ostf1 (osteoclast stimulating factor 1), Xbp1 (X-box binding protein 1), Irf3 (interferon regulatory factor 1), and Irf7 (interferon regulatory factor 7) under conditions permitting expression of the genes.

41 . The method of claim 40 , wherein the vector(s) further encode the gene Klf7 (Kruppel-like factor 7).

42 . The method of claim 40 , wherein each gene is encoded by a different vector.

43 . The method of claim 40 , wherein two or more genes are encoded by the same vector.

44 . The method of claim 41 , wherein Ostf1, Xbp1, Irf3, and Irf7 are encoded by a single vector.

45 . The method of claim 40 , further comprising co-culturing a hematopoietic stem cell (HSC) with the MSC.

46 . The method of claim 40 , wherein the MSC is bone-marrow derived, cord-blood derived, or adipose-tissue derived.

47 . The method of claim 45 , wherein the HSC is bone-marrow derived, cord-blood derived, or adipose-tissue derived.

48 . The method of claim 45 , wherein the HSC and the MSC are obtained from a subject.

49 . The method of claim 45 , wherein the MSC is pretreated with one or more vector(s), the vector(s) encoding the following genes: Ostf1, Xbp1, Irf3, and Irf7 under conditions permitting expression of the genes, and adding an amount of HSC to the MSC in culture, so as to co-culture the HSC and MSC.

50 . The method of claim 49 , wherein the vector(s) further encode the gene Klf7.

51 . The method of claim 40 , further comprising co-culturing a leukemic stem cell (LSC) with the MSC.