Detecting and counting tissue—specific stem cells and uses thereof
This invention provides methods of determining the number and percent of tissue specific stem cells (TSSCs) in a sample of cells, a population of cells or a sample of tissue. The methods rely on detecting the pattern-specific asymmetric localization of asymmetric self-renewal associated (ASRA) proteins or cell cycle specific proteins (CSSP) in cell undergoing asymmetrical self-renewal, which is a characteristic of TSSCs. The methods can be applied to any situations in which the percent of TSSC is desired such as laboratory research on adult stem cells, in drug development tests, prognostic indicator and therapeutic index, as a diagnostic and prognostic indicator and in monitoring TSSC expansion, e.g., in cell manufacturing processes.
1. A method for determining the percent of asymmetrically self-renewing dividing cells in a sample of cells comprising:
a. contacting a sample of cells with an antibody against an asymmetric self-renewal-associated (ASRA) protein to form an antibody-protein complex, wherein an antibody-protein complex is formed in situ and wherein the ASRA protein is a pattern-specific asymmetrically located protein in a cell undergoing asymmetrical cell kinetics selected from the group consisting of CXCR-6, BTG2, LGR-5 and H2A.FZ;
b. detecting sister cell pairs of dividing cells or binucleated cells;
c. detecting the antibody-protein complexes in sister cell pairs or binucleated cells, wherein the binucleated cells are arrested in cytokinesis;
d. counting the total number of cells in the sample;
e. counting the number of dividing cell comprising the pattern-specific asymmetrically localized antibody-protein complex; and
f. computing the percent of asymmetrically self-renewing dividing cells in the sample by dividing the number of step e with the number of step d.
2. A method for determining the percent of asymmetrically self-renewing dividing cells in a tissue comprising:
a. obtaining a biological sample from the tissue;
b. measuring the percent of asymmetrically self-renewing dividing cells in the biological ample from step (a) according to the method of claim 1 .
3. The method of claim 1 , wherein the sample of cells is grown and cultured in low cell density of about 1×10 3 cells/ml.
4. The method of claim 1 , wherein the sample of cells are grown and cultured in high cell density of about 1×10 5 cells/ml.
5. The method of claim 1 , wherein the sample of cells is fixed and permeabilized prior to contacting with the antibody against an ASRA protein.
6. The method of claim 1 , wherein the asymmetrically self-renewing dividing cell is an undifferentiated cell.
7. The method of claim 1 , wherein the asymmetrically self-renewing dividing cell is a tissue specific stem cell (TSSC).
8. The method of claim 7 , wherein the TSSC is a hematopoietic stem cell (HSC) or a hair follicle stem cell (HFSC).
9. The method of claim 8 , wherein the HSC is expanded for bone marrow transplantation or the HFSC is expanded for hair replacement therapy.
10. The method of claim 8 , wherein the asymmetrically self-renewing dividing cell is obtained from a source selected fromthe group consisting of cord blood, bone marrow and mobilized peripheral blood.
11. The method of claim 10 , wherein the asymmetrically self-renewing dividing cell is expanded ex vivo.
12. The method of claim 1 , wherein the ASRA protein is a pattern-specific asymmetrically located cell-cycle specific protein (CCSP).
13. The method of claim 12 , wherein the CCSP is selected from the group consisting of cyclin A, cyclin D1, cyclin E, CDKN1A, TK, Ki67, TS, DHFR and GAS-X proteins.