biostudies-literatureDeng CNICHD NIH HHSHitchcock FoundationNational Institutes of HealthNIGMS NIH HHS475-488https://www.ebi.ac.uk/biostudies/studies/S-EPMC9968987biostudies-literatureUnknown18(2)During in vitro propagation, human pluripotent stem cells (hPSCs) frequently become aneuploid with incorrect chromosome numbers due to mitotic chromosome segregation errors. Yet, it is not understood why hPSCs exhibit a low mitotic fidelity. Here, we investigate the mechanisms responsible for mitotic errors in hPSCs and show that the primary cause is lagging chromosomes in anaphase with improper merotelic microtubule attachments. Accordingly, short-term treatment (<24 h) with small molecules that prolong mitotic duration or destabilize chromosome microtubule attachments reduces merotelic errors and lagging chromosome rates, although hPSCs adapt and lagging chromosome rates rebound upon long-term (>24 h) microtubule destabilization. Strikingly, we also demonstrate that mitotic error rates correlate with developmental potential decreasing or increasing upon loss or gain of pluripotency, respectively. Thus, a low mitotic fidelity is an inherent and conserved phenotype of hPSCs. Moreover, chromosome segregation fidelity depends on developmental state in normal human cells.Stem cell reportsA pluripotent developmental state confers a low fidelity of chromosome segregation.PMC9968987GM051542R01HD101436R01 HD101436R37 GM051542Ya ADeng CCompton DAGodek KMfalseA pluripotent developmental state confers a low fidelity of chromosome segregation.During in vitro propagation, human pluripotent stem cells (hPSCs) frequently become aneuploid with incorrect chromosome numbers due to mitotic chromosome segregation errors. Yet, it is not understood why hPSCs exhibit a low mitotic fidelity. Here, we investigate the mechanisms responsible for mitotic errors in hPSCs and show that the primary cause is lagging chromosomes in anaphase with improper merotelic microtubule attachments. Accordingly, short-term treatment (<24 h) with small molecules that prolong mitotic duration or destabilize chromosome microtubule attachments reduces merotelic errors and lagging chromosome rates, although hPSCs adapt and lagging chromosome rates rebound upon long-term (>24 h) microtubule destabilization. Strikingly, we also demonstrate that mitotic error rates correlate with developmental potential decreasing or increasing upon loss or gain of pluripotency, respectively. Thus, a low mitotic fidelity is an inherent and conserved phenotype of hPSCs. Moreover, chromosome segregation fidelity depends on developmental state in normal human cells.2023-01-01T00:00:00Z2023 Feb2024-12-03T17:38:27.607Z2024-12-03T17:38:27.607ZS-EPMC99689873663878610.1016/j.stemcr.2022.12.008