Oct-4 expression in adult human differentiated cells challenges its role as a pure stem cell marker.
The Oct-4 transcription factor, a member of the POU family that is also known as Oct-3 and Oct3/4, is expressed in totipotent embryonic stem cells (ES) and germ cells, and it has a unique role in development and in the determination of pluripotency. ES may have their postnatal counterpart in the adult stem cells, recently described in various mammalian tissues, and Oct-4 expression in putative stem cells purified from adult tissues has been considered a real marker of stemness. In this context, normal mature adult cells would not be expected to show Oct-4 expression. On the contrary, we demonstrated, using reverse transcription-polymerase chain reaction (PCR) (total RNA, Poly A+), real-time PCR, immunoprecipitation, Western blotting, band shift, and immunofluorescence, that human peripheral blood mononuclear cells, genetically stable and mainly terminally differentiated cells with well defined functions and a limited lifespan, express Oct-4. These observations raise the question as to whether the role of Oct-4 as a marker of pluripotency should be challenged. Our findings suggest that the presence of Oct-4 is not sufficient to define a cell as pluripotent, and that additional measures should be used to avoid misleading results in the case of an embryonic-specific gene with a large number of pseudogenes that may contribute to false identification of Oct-4 in adult stem cells. These unexpected findings may provide new insights into the role of Oct-4 in fully differentiated cells. Disclosure of potential conflicts of interest is found at the end of this article.
Zangrossi
Stefano
S
Cell Factory, Center for Transfusion Medicine, Cellular Therapy and Cryobiology, Fondazione Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via F. Sforza 35, 20122 Milano, Italy.
Marabese
Mirko
M
Broggini
Massimo
M
Giordano
Rosaria
R
D'Erasmo
Marco
M
Montelatici
Elisa
E
Intini
Daniela
D
Neri
Antonino
A
Pesce
Maurizio
M
Rebulla
Paolo
P
Lazzari
Lorenza
L
D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology* / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D006801:Humans; D047468:Immunoprecipitation; D050814:Octamer Transcription Factor-3 / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D015415:Biomarkers; D050814:Octamer Transcription Factor-3; D012333:RNA, Messenger