MULTIPOTENT STEM CELLS AND USES THEREOF
The invention provides a quiescent stem cell having the capacity to differentiate into ectoderm, mesoderm and endoderm, and which does not express cell surface markers including MHC class I, MHC class II, CD44, CD45, CD13, CD34, CD49c, CD73, CD105, CD90, CD66A, CD66E, CXCR4, CD133 or an SSEA. The invention further provides a proliferative stem cell, which expresses genes including Oct-4, Nanog, Sox2, GDF3, P16INK4, BMI, Notch, HDAC4, TERT, Rex-1, TWIST, KLF-4 and Stella but does not express cell surface markers including MHC class I, MHC class II, CD44, CD45, CD13, CD34, CD49c, CD73, CD105, CD90, CD66A, CD66E, CXCF4, CD133 or an SSEA. The cells of the invention can be isolated from adult mammals, have embryonic cell characteristics, and can form embryoid bodies. Methods for obtaining the stem cells, as well as methods of treating diseases and differentiating the stem cells, are also provided.
1 . A method of isolating a population of MHC class I − stem cells from synovial fluid, said method comprising the steps: (a) providing synovial fluid from a subject; (b) enriching for a population of cells that are about 6 μm to 20 μm in size; and (c) depleting from said population cells expressing a stem cell surface marker and cells expressing an MHC class I protein, thereby isolating a population of MHC class I − stem cells from synovial fluid.
2 . The method of claim 1 , further comprising testing the isolated population of MHC Class I − stem cells for the expression of one or more cell surface markers selected from the group consisting of CD13, CD44, CD45, CD90 and CD105.
3 . The method of claim 2 , further comprising testing the isolated population of MHC Class I − stem cells for the expression of one or more cell surface markers selected from the group consisting of MHC class II, CD34, CD49c and CD73.
4 . The method of claim 1 , further comprising testing the isolated population of MHC Class I − stem cells for the expression of one or more stem cell transcription factors selected from the group consisting of Oct-4, Nanog, Sox-2, Rex-1, GDF-3 and Stella.
5 . The method of claim 1 , further comprising testing the isolated population of MHC Class I − stem cells for the expression of the stem cell surface markers CD13, CD44, CD45, CD90, CD105, MHC class II, CD34, CD49c and CD73.
6 . The method of claim 1 , further comprising testing the isolated population of MHC Class I − stem cells for the expression of the stem cell transcription factors Oct-4, Nanog, Sox-2, Rex-1, GDF-3 and Stella.