Mesenchymal stem cells with enhanced immunosuppressive capability
Compositions of HLA-G + MSC and methods of using them, including methods of transplanting compositions of HLA-G + MSC into human recipients, are provided. Also provided are methods of preparing compositions of HLA-G + MSC, including by treatment with DNA methylation inhibitors.
1. A method of generating a composition of undifferentiated HLA-G + mesenchymal stem cells (MSCs), the method comprising:
(a) maintaining a population of mammalian tissue-derived MSCs for at least two passages in non-differentiating in vitro culture conditions,
(b) contacting the population of MSCs from step (a) with an effective amount of a DNA methylation inhibitor, and
(c) maintaining the population of MSCs exposed to the DNA methylation inhibitor in step (b) in non-differentiating conditions for at least two passages in the absence of the DNA methylation inhibitor, thereby producing the composition of undifferentiated HLA-G + MSCs.
2. The method of claim 1 , wherein the composition of HLA-G + MSCs express HLA-G1 and/or HLA-G3.
3. The method of claim 1 , wherein the composition of HLA-G + MSCs express HLA-G1 and HLA-G3 and do not express HLA-G5.
4. The method of claim 1 , wherein the mammalian tissue-derived MSC is derived from adipose tissue, or bone marrow.
5. The method of claim 1 , wherein the DNA methylation inhibitor is selected from a group comprising 5-aza-2′-deoxycytidine, 5-aza-cytidine, 2-pyrimidone-1-β-D-riboside, procainamide, procaine, hydralazine and epigallocatechin-3-gallate.
6. The method of claim 1 , wherein the DNA methylation inhibitor is 5-aza-2′-deoxycytidine.
7. The method of claim 1 , wherein in step (a) the population of mammalian tissue-derived MSC is maintained in non-differentiating in vitro culture conditions for at least five passages.
8. The method of claim 1 , wherein at least 25%, at least 50%, or at least 90% of the MSCs in the composition of HLA-G + MSCs express HLA-G.
9. The method of claim 1 , wherein the HLA-G expression in the HLA-G + MSCs is assessed by detecting the corresponding mRNA or its transcript.
10. The method of claim 1 , wherein the HLA-G expression in the HLA-G + MSCs is assessed by detecting the cell surface expression of HLA-G.
11. The method of claim 1 , wherein the HLA-G expression in the population of mammalian tissue-derived MSC treated with a DNA methylation inhibitor in step (b) is at least 10%, at least 50%, or at least 100% higher than in a population of untreated MSC.
12. The method of claim 1 , wherein the composition of HLA-G + MSCs maintains the expression of HLA-G for the at least two passages in non-differentiating conditions in the absence of a DNA methylation inhibitor of step (c).
13. The method of claim 1 , wherein step (c) comprises maintaining the population of MSCs exposed to the DNA methylation inhibitor in step (b) in non-differentiating conditions for at least five passages in the absence of the DNA methylation inhibitor.
14. The method of claim 13 , wherein the composition of HLA-G + MSCs maintains the expression of HLA-G for the at least five passages in non-differentiating conditions in the absence of a DNA methylation inhibitor of step (c).
15. The method of claim 1 , wherein step (a) comprises maintaining the population of mammalian tissue-derived MSC in non-differentiating in vitro culture conditions for at least ten passages.