{"doi":"10.1093/lifemedi/lnac024","title":"Hidden totipotency in naïve human pluripotent stem cell cultures","abstract":"Capturing totipotency in a dish has the potential to revolutionize basic science and translational medicine. Human totipotent-like cells have now been found within cultures of naïve human pluripotent stem cells and are able to give rise to both embryonic and extraembryonic tissues. The understanding of human early embryogenesis is key to developing treatments for human developmental disease and infertility, but it has been hampered by ethical, legal, and technical limitations involving research using actual human embryos. Because of this, researchers have developed various in vitro models of early human embryogenesis to act as accessible proxies for human embryos. The workhorse of the early embryo modeling field has been the pluripotent stem cell (PSC). These cells have the remarkable ability to give rise to any cell in the adult body and can ­self-renew indefinitely in culture. In the context of embryogenesis, PSCs act as the in vitro representation of the pluripotent epiblast which gives rise to the embryo proper but not extraembryonic tissues. Thus, in general, PSCs lack the developmental capacity to give rise to extraembryonic tissues. Because of this limitation, a great effort has been made in recent years to generate in vitro cell lines that have an even greater developmental capacity than that of PSCs: totipotent stem cells. By the strictest definition, totipotency refers to the ability of a cell to give rise to an entire embryo including extraembryonic tissues. Totipotent cells have the highest developmental potential of any cell, and in mouse embryos totipotency lasts for ~1.5 days where only the one- and two-cell stage blastomeres are truly totipotent. The establishment of totipotent stem cells in vitro has the potential to revolutionize early embryo research, reproductive biology and regenerative medicine, and would allow for the generation of any cell, tissue, or, potentially, organism from a single cell type. However, the identification and stabilization of stem cells with totipotent characteristics in vitro proved to be exceedingly difficult, as it took nearly 30 years after the first derivation of PSCs to generate mammalian totipotent-like cells in culture. A decade ago, Macfarlan et al. published a groundbreaking study in which they identified a rare and transient subpopulation of totipotent-like cells within naïve mouse embryonic stem cell (mESC) cultures [1]. These cells spontaneously upregulated the expression of many genes exclusively expressed in 2-cell (2C) embryos. Moreover, these cells, which they called 2C-like cells (2CLCs), were able to give rise to both embryonic and extraembryonic tissues in vivo. The 2CLCs could be identified by expression of the retrotransposon MERVL, which in turn was used to generate a 2CLC reporter. However, only <1% of cells in naïve mESC culture were found to be in this 2C-like state at any given time. Nonetheless, this was the first report of totipotent-like cells in culture and inspired many studies aimed toward increasing the stability of totipotent-like cells. Later, the retrogene DUX was identified as the master regulator of entering the 2C-like state in mESCs. Using an inducible expression system, Dux was found to be both necessary and sufficient to convert naïve mESCs into the 2C-like state and was able to increase the proportion of 2CLCs from <1% to >70% [2]. In 2021, Shen et al. identified spliceosomal repression as a method to promote a pluripotent-to-totipotent transition using the splicing inhibitor pladienolide B, which allowed for the stabilization of totipotent blastomere-like cells [3]. Shortly after, two separate groups both generated novel mouse totipotent-like cells from mouse embryos and mESC cultures by modulating the activity of epigenetic enzymes [4, 5]. Despite the advances being made for stabilizing mouse totipotent-like cells, little progress had been made in establishing a human counterpart. The identification of human totipotent-like cells in cult","journal":"Life Medicine","year":2022,"id":292034,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9492,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":364485,"name":"Jun Wu","orcid":"0000-0001-9863-1668","position":1,"is_corresponding":false},{"id":848402,"name":"Daniel A. Schmitz","orcid":"0000-0002-2112-5561","position":0,"is_corresponding":true}],"reference_count":11,"raw_metadata":null,"created_at":"2026-07-19T00:30:42.221508Z","pmid":"36817554","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}