title: Generation of multipotent cell lines from a distinct population of male germ line stem cells.
abstract: Spermatogonial stem cells (SSCs) maintain spermatogenesis by self-renewal and generation of spermatogonia committed to differentiation. Under certain in vitro conditions, SSCs from both neonatal and adult mouse testis can reportedly generate multipotent germ cell (mGC) lines that have characteristics and differentiation potential similar to embryonic stem (ES) cells. However, mGCs generated in different laboratories showed different germ cell characteristics, i.e., some retain their SSC properties and some have lost them completely. This raises an important question: whether mGC lines have been generated from different subpopulations in the mouse testes. To unambiguously identify and track germ line stem cells, we utilized a transgenic mouse model expressing green fluorescence protein under the control of a germ cell-specific Pou5f1 (Oct4) promoter. We found two distinct populations among the germ line stem cells with regard to their expression of transcription factor Pou5f1 and c-Kit receptor. Only the POU5F1+/c-Kit+ subset of mouse germ line stem cells, when isolated from either neonatal or adult testes and cultured in a complex mixture of growth factors, generates cell lines that express pluripotent ES markers, i.e., Pou5f1, Nanog, Sox2, Rex1, Dppa5, SSEA-1, and alkaline phosphatase, exhibit high telomerase activity, and differentiate into multiple lineages, including beating cardiomyocytes, neural cells, and chondrocytes. These data clearly show the existence of two distinct populations within germ line stem cells: one destined to become SSC and the other with the ability to generate multipotent cell lines with some pluripotent characteristics. These findings raise interesting questions about the relativity of pluripotency and the plasticity of germ line stem cells.
authors.affiliation: PrimeGen Biotech LLC, 213 Technology Drive, Irvine, California 92618, USA. fizadyar@primegenbiotech.com
authors.forename: Fariborz
authors.initials: F
authors.lastname: Izadyar
authors.forename: Francis
authors.initials: F
authors.lastname: Pau
authors.forename: Joel
authors.initials: J
authors.lastname: Marh
authors.forename: Natalia
authors.initials: N
authors.lastname: Slepko
authors.forename: Tracy
authors.initials: T
authors.lastname: Wang
authors.forename: Rafael
authors.initials: R
authors.lastname: Gonzalez
authors.forename: Thomas
authors.initials: T
authors.lastname: Ramos
authors.forename: Kyle
authors.initials: K
authors.lastname: Howerton
authors.forename: Chauncey
authors.initials: C
authors.lastname: Sayre
authors.forename: Francisco
authors.initials: F
authors.lastname: Silva
mesh_terms: D000818:Animals; D015415:Biomarkers; D019070:Cell Lineage / Q000502:physiology; D002478:Cells, Cultured; D002678:Chimera; D005818:Genetic Engineering; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007621:Karyotyping; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D039902:Multipotent Stem Cells / Q000166:cytology* / Q000201:enzymology; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D011401:Promoter Regions, Genetic; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D013093:Spermatogonia / Q000166:cytology* / Q000201:enzymology; D033581:Stem Cell Transplantation / Q000379:methods; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology; D019098:Telomerase / Q000378:metabolism; D013724:Teratoma / Q000473:pathology
chemical_list: D015415:Biomarkers; D050814:Octamer Transcription Factor-3; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit; D019098:Telomerase