Reaching for Consensus on a Naming Convention for Pluripotent Cells

Based on its history as a repository of biomaterial diversity, the ATCC recognizes the importance of a naming convention that is both clearly descriptive and consistently applied. We therefore agree with and support the objective of the authors of “A Call for Standardized Naming and Reporting of Human ESC and iPSC Lines” (Luong et al., 2011xLuong, M.X., Auerbach, J., Crook, J.M., Daheron, L., Hei, D., Lomax, G., Loring, J.F., Ludwig, T., Schlaeger, T.M., Smith, K.P. et al. Cell Stem Cell. 2011; 8: 357–359Abstract | Full Text | Full Text PDF | PubMed | Scopus (15)See all ReferencesLuong et al., 2011). We have some additional suggestions to clarify and broaden the naming convention.Pluripotent stem cell lines of various sources display significant differences in methylation signature and/or differentiation ability (Hanna et al., 2010xHanna, J., Cheng, A.W., Saha, K., Kim, J., Lengner, C.J., Soldner, F., Cassady, J.P., Muffat, J., Carey, B.W., and Jaenisch, R. Proc. Natl. Acad. Sci. USA. 2010; 107: 9222–9227Crossref | PubMed | Scopus (390)See all References, Bock et al., 2011xBock, C., Kiskinis, E., Verstappen, G., Gu, H., Boulting, G., Smith, Z.D., Ziller, M., Croft, G.F., Amoroso, M.W., Oakley, D.H. et al. Cell. 2011; 144: 439–452Abstract | Full Text | Full Text PDF | PubMed | Scopus (409)See all References, Lister et al., 2011xLister, R., Pelizzola, M., Kida, Y.S., Hawkins, R.D., Nery, J.R., Hon, G., Antosiewicz-Bourget, J., O'Malley, R., Castanon, R., Klugman, S. et al. Nature. 2011; 471: 68–73Crossref | PubMed | Scopus (759)See all References, Burridge et al., 2011xBurridge, P.W., Thompson, S., Millrod, M.A., Weinberg, S., Yuan, X., Peters, A., Mahairaki, V., Koliatsos, V.E., Tung, L., and Zambidis, E.T. PLoS ONE. 2011; 6: e18293Crossref | PubMed | Scopus (157)See all References, Kattman et al., 2011xKattman, S.J., Witty, A.D., Gagliardi, M., Dubois, N.C., Niapour, M., Hotta, A., Ellis, J., and Keller, G. Cell Stem Cell. 2011; 8: 228–240Abstract | Full Text | Full Text PDF | PubMed | Scopus (397)See all References). As such, there is an ever-growing call for standardization to define what “pluripotent cell” means as a strict cell biology definition. This definition will be more accurately determined if we include the character of pluripotent cells of all types. Therefore, the naming convention should include designations for embryonal carcinoma cells, parthenogenic stem cells, and epiblast stem cells in addition to the i or e used to designate the induced or embryonic origin of pluripotency.In addition, we caution against use of the word “disease” in naming pluripotent cells as this breeds ambiguity. Many iPSCs have been derived from neonatal foreskin fibroblasts, and thus serve as nondiseased controls. Because of anonymization of donors, it is unknown whether they may display disease later in life or have children who grow up to develop a disease where the donor is a carrier or where disease penetrance is variable. For many multifactorial disorders, disease etiology is complex; diseases such as diabetes or cardiovascular disease have divergent genetic origins. This susceptibility to disease may not be manifest in the iPSCs or in any of the differentiated cell types derived from them (Soldner et al., 2009xSoldner, F., Hockemeyer, D., Beard, C., Gao, Q., Bell, G.W., Cook, E.G., Hargus, G., Blak, A., Cooper, O., Mitalipova, M. et al. Cell. 2009; 136: 964–977Abstract | Full Text | Full Text PDF | PubMed | Scopus (884)See all ReferencesSoldner et al., 2009). Therefore, the terms “healthy” and “diseased” do not have clear meaning in the context of pluripotent cells. After all, no pluripotent cell donor is normal or healthy, but somewhere within a spectrum of genetic diversity and susceptibility to disease. We suggest that the specification of disease should be replaced by a descriptor of the known genetic mutation or lack of known genetic mutations. Medical history of the donor is too long to be included in the name, and should be found in any accompanying cell description.A last but practical point to be considered is that the name should be short enough to fit clearly on the label of a 1.5 ml cryoampule when written with an indelible marker by a gloved hand. That is a tall order, but we suggest that the character number should not be more than 10.We would propose that the following be key elements of the name: lab origin (two letter code, similar to the system used to name candidate drugs); source organ (two letters such as ec for embryonal carcinoma); sex (X or Y); presence or absence of permanent genetic modification (i for insertions, n for no insertions); and a unique four-number code that would be linked to a known genetic identity or subclone from a parent line.As a member of the stem cell research community, the ATCC expects that pluripotent cells will continue to have a transformative effect on the study of human disease, the evaluation of drugs, and the replacement of damaged tissues. The ATCC feels that the standardization of naming, cell definition, and cell character are all essential measures to help realize that potential. Recognizing the positive impact a nonprofit organization that specializes in preserving biomaterial diversity can have in this area, the ATCC has established a repository exclusive to pluripotent cells. In accordance with the ATCC mission, this repository was designed with the goal of enabling research by providing cells that are licensed for research use.The cells in the ATCC repository will meet the criteria for pluripotency established through dialog with experts in the field. Quality, consistency, and reliability will be assured through the application of rigorous QC specifications. In conjunction with this effort, the ATCC is devoting resources to create an online database to store and organize descriptive and experimental data related to pluripotent cells. The ATCC will seek the participation of stem cell researchers in the creation of these tools in order to harmonize the practices that will ultimately lead to more transparent and accessible sharing of pluripotent cells.