Genes Involved in Stem Cell Proliferation Influenced by Biomaterials on Which they Are Grown

Genes Involved in Stem Cell Proliferation Influenced by Biomaterials on Which they Are Grown

A variety of different substrates are used in the lab for growing stem cells. The substrates provide a surface on which stem cells adhere to. While some studies have suggested the type of substrate used can influence molecular changes in the cells, the impact on the cells was thought to be minimal.

A team of researchers at the University of Toronto Donnelly Centre for Cellular and Biomolecular Research have now studied the molecular changes in stem cells grown on different substrates in more detail. Their research suggests that the substrate has more of an impact than was previously thought and the molecular changes that are induced as a result should be considered in future research.

The researchers were conducting a study to identify genes that are essential for the proliferation of embryonic stem cells. They discovered two commonly used substrates for growing stem cells had a profound effect on the molecular properties of the cells. The researchers believe that substrate molecules are interacting with receptors on the surface of stem cells, which results in molecular changes inside the cells.

To test the effect of substrate choice, the researchers split a batch of stem cells and cultured them in dishes using different substrates. While several substrates were tested, two were found to have a significant effect on the cultured cells.

Cells cultured on mouse embryonic fibroblasts (MEFs) and laminin differed substantially at the molecular level. The researchers used embryonic stem cells with an inducible CRISPR switch that allowed them to turn approximately 20,000 genes off and on one by one to determine which were necessary for pluripotent cell growth. They discovered the proliferation of pluripotent stem cells was controlled by partially overlapping sets of genes. Around half of the genes that were turned on in the MEF and laminin cultured cells differed.

“Our study provides the stem cell field with data to assess how their substrate can inherently bias their cells’ genetic makeup even before they start doing any experiments,” said post-doctoral researcher Barbara Mair, co-author of the study.

In addition to demonstrating the different effects of substrates on cultured cells, the researchers also identified several new genes that are essential for stem cell proliferation on both substrates, which will be studied in future research.

The findings are detailed in the paper – Essential Gene Profiles for Human Pluripotent Stem Cells Identify Uncharacterized Genes and Substrate Dependencies – which was recently published in the journal Cell Reports. DOI: 10.1016/j.celrep.2019.02.041

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