Methods and compositions for isolation and growth of kidney tubule stem cells, in vitro kidney tubulogenesis and ex vivo construction of renal tubules

A method for growing kidney tubule stem cells ex vivo, comprising culturing kidney cells in the presence of all-trans retinoic acid, transforming growth factor-.beta..sub.1, and either epidermal growth factor or transforming growth factor-.alpha., in amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells such that condensed aggregates of tubule cells form about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border.

A method of expressing a therapeutically useful polypeptide in an ex vivo renal tubule system, comprising:

• transforming an ex vivo renal tubule system prepared by a process comprising culturing kidney cells in a culture medium comprising all-trans retinoic acid, transforming growth factor-.beta.1 and either epidermal growth factor or transforming growth factor-.alpha. in an amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells such that condensed aggregates of tubule cells form about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border;
• and
• culturing the transformed ex vivo renal tubule system for a time sufficient to express a therapeutically useful polypeptide.

An ex vivo renal tubule tissue system prepared by a process comprising culturing kidney cells in a culture medium comprising all-trans retinoic acid and either epidermal growth factor or transforming growth factor-.alpha. in an amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells such that condensed aggregates of tubule cells form about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border.

A method for growing kidney tubule stem cells ex vivo, comprising culturing kidney cells in the presence of all-trans retinoic acid and either epidermal growth factor or transforming growth factor-.alpha., in an amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells such that condensed aggregates of tubule cells form about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border.

A method for effecting tubulogenesis in a renal cell culture ex vivo, comprising culturing kidney cells in the presence of all-trans retinoic acid and either epidermal growth factor or transforming growth factor-.alpha. in an amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells such that condensed aggregates of tubule cells form about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border.

A method for constructing and maintaining an ex vivo renal tubule tissue system, comprising culturing kidney cells in the presence of all-trans retinoic acid and either epidermal growth factor or transforming growth factor-.alpha. in an amount effective for achieving tubulogenesis, wherein tubulogenesis is a phenotypic transformation of said cells characterized by condensed aggregates of tubule cells forming about a central lumen wherein said lumen is bordered by cells possessing a polarized epithelial phenotype with extensive microvilli formation and tight junctional complexes along the lumenal border.