Biology subjects

Laing, O.

Publications and source records attributed to Laing, O..

3 recordsLinked to original sources

bioRxiv2023

Aberrant Wnt activation in recurrent genetically variant human pluripotent stem cells impairs cardiomyocyte differentiation and phenotype

Human pluripotent stem cell (hPSC)-derived cardiomyocytes have emerged as powerful tools for disease modelling and cell therapy. The production of cardiomyocytes from hPSCs typically requires expanding large numbers of hPSCs and maintaining them in culture for extended periods of time. This in turn predisposes hPSCs to the acquisition of non-random genetic changes, including recurrent gains of chromosome 1q. Here, we show that gain of chromosome 1q in hPSCs affects both the efficiency of differentiation to cardiomyocytes and phenotype of the differentiated cells. Mechanistically, we show that aberrant activation of the Wnt signalling pathway underpins the skewed differentiation of variant 1q hPSCs. Collectively, our data demonstrates that the presence of genetically variant cells in cultures is a significant concern for production of hPSC-derived cardiomyocytes for research or clinical applications. Further, our results suggest new approaches for removing genetically variant cells for future clinical applications.

cell biology↗

bioRxiv2023

Cytogenetic resource enables mechanistic resolution of changing trends in human pluripotent stem cell aberrations linked to feeder-free culture

Since the first derivation of human pluripotent stem cells (hPSCs), the number of culture conditions has steadily increased, making hPSC culture more facile. Nonetheless, there remains the persistent issue of culture-acquired genetic changes, hampering the reproducibility of hPSC research and jeopardising their clinical use. Here, we utilised comprehensive karyotyping datasets from over 20,000 hPSC cultures sampled under different conditions to ascertain association of genetic changes with specific culture regimens. We found condition-dependent patterns of aberrations, with higher prevalence of chromosome 1q gains in recent years, associated with increased use of contemporary, feeder-free cultures. Mechanistically, we show the context-dependent selection of 1q variants is mainly driven by MDM4, a gene amplified in many cancers, located on chromosome 1q. To facilitate reproducibility of hPSC research and their safe clinical utility, we provide a unique hPSC karyotype resource for informing the risk assessment of genetic aberrations and developing strategies to suppress their occurrence.

cell biology↗

bioRxiv2019

Nucleosides rescue replication-mediated genome instability of human pluripotent stem cells

Human pluripotent stem cells (PSC) often acquire genetic changes on prolonged culture, which pose concerns for their use in research and regenerative medicine (Amps et al., 2011, Seth et al., 2011). The acquisition of these changes during culture necessarily first requires mutation and then selection of those mutations that provide a growth advantage. Whilst selection accounts for the recurrent nature of the variants commonly reported (Draper et al., 2004, Olariu et al., 2010), the mechanisms of mutation in PSC remain largely elusive. Here we show that, in contrast to somatic cells, human PSC have an increased susceptibility to DNA damage and mitotic errors, both of which are caused by heightened replication stress in PSC and this can be alleviated by culture with exogenous nucleosides. These results reflect the requirement for rapid replication of human PSC enabled by a truncated G1 (Becker et al., 2006, Becker et al., 2010) that impairs the preparation of these cells for the ensuing DNA replication. A similar relationship has been shown in relation to chromosomal instability in cancer cells (Burrell et al., 2013, Wilhelm et al., 2019) but PSC differ by replication stress triggering apoptosis (Desmarais et al., 2012, Desmarais et al., 2016). Nevertheless, evasion of this response still leads to the appearance of genetic variants that are of concern for regenerative medicine. The inclusion of nucleosides into culture media greatly improves the efficiency of human PSC culture and minimises the acquisition of genomic damage.

cell biology↗