Compositions and methods of making embryonic stem cells

Abstract

The invention relates to cell proliferation, cell differentiation, male infertility, male fertility and to compositions and methods involved therein.

What is claimed is:  
     
         1 . A method of proliferating mammalian spermatogonial stem cells, comprising culturing spermatogonial stem cells in the presence of BMP8, or a biologically active fragment or an agonist thereof, to effect proliferation of said cells.  
     
     
         2 . A method of differentiating mammalian spermatogonial stem cells, comprising culturing spermatogonial stem cells in the presence of BMP, or a biologically active fragment or an agonist thereof, to effect differentiation of said cells.  
     
     
         3 . A method of extending viability of a mammalian spermatogonial cell population, comprising culturing said spermatogonial cell population in the presence of BMP8, or a biologically active fragment or an agonist thereof, thereby extending the viability of said cultured spermatogonial cell population.  
     
     
         4 . A method of inducing apoptosis of spermatocytes in culture comprising incubating said spermatocytes in the substantial absence of BMP8, or a biologically active fragment or an agonist thereof, thereby inducing apoptosis of spernatocytes.  
     
     
         5 . A method of inhibiting proliferation of spermatogonial stem cells in culture, comprising incubating a population of spermatogenic cells in the substantial absence of BMP8 to effect inhibition of proliferation of said cells.  
     
     
         6 . A method of effecting the proliferation of mammalian spermatogonial stem cells in vivo in a mammal, comprising administering to said mammal BMP8, or a biologically active fragment or an agonist thereof, suspended in a pharmaceutically acceptable carrier, to effect proliferation of said cells in said mammal.  
     
     
         7 . A method of effecting differentiation of mammalian spermatogonial stem cells in vivo in a mammal, comprising administering to said mammal BMP8, or a biologically active fragment or an agonist thereof, suspended in a pharmaceutically acceptable carrier, to effect differentiation of said cells in said mammal.  
     
     
         8 . A method of extending viability of a mammalian spermatogonial cell population in vivo in a mammal, comprising administering to said mammal BMP8, or a biologically active fragment or an agonist thereof, suspended in a pharmaceutically acceptable carrier, thereby extending the viability of said mammalian spermatogonial cell population in said mammal.  
     
     
         9 . A method of inducing apoptosis of spermatocytes in vivo in a mammal comprising administering to said mammal BMP8, or a biologically active fragment or an agonist thereof, suspended in a pharmaceutically acceptable carrier, thereby inducing apoptosis of spermatocytes in said mammal.  
     
     
         10 . A method of inhibiting proliferation of spermatogonial stem cells in vivo in a mammal, comprising administering to said mammal an antagonist of BMP8 suspended in a pharmaceutically acceptable carrier, to effect inhibition of proliferation of said cells in said mammal.  
     
     
         11 . A method of selectively obtaining a proliferating population of spermatogonial stem cells in culture, comprising adding BMP8 to said population of cells, thereby selectively obtaining a proliferating population of spermatogonial stem cells.  
     
     
         12 . A method of treating infertility in a male mammal, comprising administering to said mammal BMP8, or a biologically active fragment or an agonist thereof, suspended in a pharmaceutically acceptable carrier.  
     
     
         13 . The method of  claim 12 , wherein said BMP8 is administered to the testes of said mammal.  
     
     
         14 . A mammalian male contraceptive comprising a BMP8 antagonist.  
     
     
         15 . A method of identifying an antagonist of BMP8, comprising adding a test compound to a culture of spermatogonial cells in the presence or absence of BMP8 and measuring the level of proliferation or differentiation of said cells, wherein a lower level of proliferation or differentiation of said cells in the presence of said test compound, compared with the level of proliferation or differentiation of said cells in the absence of said test compound, is an indication that said test compound is a BMP8 antagonist.  
     
     
         16 . A method of identifying an agonist of BMP8, comprising adding a test compound to a culture of spermatogonial cells in the presence or absence of BMP8 and measuring the level of proliferation or differentiation of said cells, wherein a higher level of proliferation or differentiation of said cells in the presence of said test compound, compared with the level of proliferation or differentiation of said cells in the absence of said test compound, is an indication that said test compound is a BMP8 agonist.  
     
     
         17 . A method of stimulating hair growth in a mammal, comprising administering a hair growth stimulating amount of BMP8 to the hair follicles of said mammal.  
     
     
         18 . A method of isolating a BMP8 receptor on a cell comprising binding BMP8 to a BMP8-responsive population of cells, and isolating the protein on said cells to which said BMP8 binds.  
     
     
         19 . A purified population of spermatogonial stem cells.  
     
     
         20 . A method of making a population of mammalian pluripotent embryonic stem cell, comprising incubating a population of spermatogenic cells in a composition comprising a growth enhancing amount of basic fibroblast growth factor, leukemia inhibitory factor, membrane associated steel factor, and soluble steel factor, thereby making a population of pluripotential embryonic stem cells.  
     
     
         21 . A population of pluripotential embryonic stem cells produced by the method of  claim 20 .  
     
     
         22 . A composition comprising BMP8, a fibroblast growth factor, leukemia inhibitory factor, membrane associated steel factor, and soluble steel factor in amounts to enhance the growth of and allow the continued proliferation of germ cells and the formation of pluripotent embryonic stem cells from said germ cells.