Compositions and methods for the quality control of stem cell preparations
Provided herein are methods and compositions for assessing the quality and potential of stem cells in a sample. Such methods and compositions are useful for helping to ensure the safety and quality of a population of stem cells before it is used in a subject.
1. A method of selecting a sample comprising a population of stem cells, for use in a stem cell-based therapy, the method comprising:
a. measuring the expression levels of at least two miRNAs in the sample, wherein the at least two miRNAs are mir-125b1 and mir-let7a-2;
b. comparing the expression levels of the at least two miRNAs to a reference standard;
c. using the comparison to determine the quality of the stem cells in the sample wherein an increase in the expression level of the at least two miRNAs compared to the reference standard is correlated with a decrease in the quality of the stem cells in the sample and the quantity of productive stem cells in the sample;
d. determining the percentage of unproductive stem cells in the sample, wherein the percentage of unproductive stem cells in the sample is determined by:
detecting the increase in the expression level of the at least two miRNAs; and
detecting one or more stem cell features selected from:
the stem cells are not or are minimally self-renewing;
the stem cells are senescent or are nearing senescence;
the stem cells have been passaged greater than 6 times;
the stem cells exhibit low or no growth potential; and
the stem cells exhibit tumorigenic potential; and
e. (i) selecting and preparing the sample for use in a stem cell-based therapy if 50% or less than 50% of cells in the sample comprise unproductive stem cells by separating unproductive cells from the sample and purifying or enriching the sample for productive stem cells or (ii) separating unproductive cells from the sample if greater than 50% of cells in the sample comprise unproductive stem cells.
2. The method of claim 1 , wherein the unproductive stem cells are not self-renewing.
3. The method of claim 1 , wherein the sample comprises human stem cells.
4. The method of claim 1 , wherein the sample comprises mesenchymal stem cells.
5. The method of claim 1 , wherein the sample comprises adipose tissue.
6. The method of claim 1 , wherein the sample comprises mesodermal tissue differentiated from induced pluripotent stem cells.
7. The method of claim 1 , wherein the sample comprises bone marrow-derived stem cells.
8. The method of claim 1 , wherein the separating step is carried out by any one or more of magnetic beads technology, differential attachment assays, visual morphological inspections, and differential migration assays.
9. The method of claim 1 , wherein the separating of step (e)(i) is carried out by any one or more of magnetic beads technology, differential attachment assays, visual morphological inspections, and differential migration assays.
10. The method of claim 1 , wherein the expression level of the miRNAs is increased by at least 2-fold.
11. The method of claim 1 , wherein the enriching or purifying of step (e)(i) comprises incubating a β-galactosidase substrate with the stem cells and selecting for β-galactosidase activity.