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  • Preventing erosion of X-chromosome inactivation in human embryonic stem cells.

Preventing erosion of X-chromosome inactivation in human embryonic stem cells.

Nature communications (2022-05-07)
Marissa Cloutier, Surinder Kumar, Emily Buttigieg, Laura Keller, Brandon Lee, Aaron Williams, Sandra Mojica-Perez, Indri Erliandri, Andre Monteiro Da Rocha, Kenneth Cadigan, Gary D Smith, Sundeep Kalantry
ABSTRACT

X-chromosome inactivation is a paradigm of epigenetic transcriptional regulation. Female human embryonic stem cells (hESCs) often undergo erosion of X-inactivation upon prolonged culture. Here, we investigate the sources of X-inactivation instability by deriving new primed pluripotent hESC lines. We find that culture media composition dramatically influenced the expression of XIST lncRNA, a key regulator of X-inactivation. hESCs cultured in a defined xenofree medium stably maintained XIST RNA expression and coating, whereas hESCs cultured in the widely used mTeSR1 medium lost XIST RNA expression. We pinpointed lithium chloride in mTeSR1 as a cause of XIST RNA loss. The addition of lithium chloride or inhibitors of GSK-3 proteins that are targeted by lithium to the defined hESC culture medium impeded XIST RNA expression. GSK-3 inhibition in differentiating female mouse embryonic stem cells and epiblast stem cells also resulted in a loss of XIST RNA expression. Together, these data may reconcile observed variations in X-inactivation in hESCs and inform the faithful culture of pluripotent stem cells.

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