integration-free-derivation-human-induced-pluripotent-stem-cells

Integration Free Derivation of Human Induced Pluripotent Stem Cells Using Laminin 521 Matrix

Xeno-free and fully defined conditions are key parameters for robust and reproducible generation of homogenous human induced pluripotent stem (hiPS) ...

Karolinska Institutet

Culturing stem cells as free-floating aggregates in suspension facilitates large-scale production of cells in closed systems, for clinical use. To comply with GMP standards, the use of substances such as proteolytic enzymes should be avoided. Instead of enzymatic dissociation, the growing cell aggregates may be mechanically cut at passage, but available methods are not compatible with large-scale cell production and hence translation into the clinic becomes a severe bottle-neck. We have developed the Biogrid device, which consists of an array of micrometerscale knife edges, micro-fabricated in silicon, and a manifold in which the microgrid is placed across the central fluid channel. By connecting one side of the Biogrid to a syringe or a pump and the other side to the cell culture, the culture medium with suspended cell aggregates can be aspirated, forcing the aggregates through the microgrid, and ejected back to the cell culture container. Large aggregates are thereby dissociated into smaller fragments while small aggregates pass through the microgrid unaffected. As proof-of-concept, we demonstrate that the Biogrid device can be successfully used for repeated passage of human neural stem/progenitor cells cultured as so-called neurospheres, as well as for passage of suspension cultures of human embryonic stem cells. We also show that human neural stem/progenitor cells tolerate transient pressure changes far exceeding those that will occur in a fluidic system incorporating the Biogrid microgrids. Thus, by using the Biogrid device it is possible to mechanically passage large quantities of cells in suspension cultures in closed fluidic systems, without the use of proteolytic enzymes.

Biogrid--a microfluidic device for large-scale enzyme-free dissociation of stem cell aggregates.

Human embryonic stem cell differentiation towards various cell types belonging to ecto-, endo- and mesodermal cell lineages has been demonstrated, with high efficiency rates using standardized differentiation protocols. However, germ cell differentiation from human embryonic stem cells has been very inefficient so far. Even though the influence of various growth factors has been evaluated, the gene expression of different cell lines in relation to their differentiation potential has not yet been extensively examined. In this study, the potential of three male human embryonic stem cell lines to differentiate towards male gonadal cells was explored by analysing their gene expression profiles. The human embryonic stem cell lines were cultured for 14 days as monolayers on supporting human foreskin fibroblasts or as spheres in suspension, and were differentiated using BMP7, or spontaneous differentiation by omitting exogenous FGF2. TLDA analysis revealed that in the undifferentiated state, these cell lines have diverse mRNA profiles and exhibit significantly different potentials for differentiation towards the cell types present in the male gonads. This potential was associated with important factors directing the fate of the male primordial germ cells in vivo to form gonocytes, such as SOX17 or genes involved in the NODAL/ACTIVIN pathway, for example. Stimulation with BMP7 in suspension culture resulted in up-regulation of cytoplasmic SOX9 protein expression in all three lines. The observation that human embryonic stem cells differentiate towards germ and somatic cells after spontaneous and BMP7-induced stimulation in suspension emphasizes the important role of somatic cells in germ cell differentiation in vitro.

A Combination of Culture Conditions and Gene Expression Analysis Can Be Used to Investigate and Predict hES Cell Differentiation Potential towards Male Gonadal Cells.

CTL07-II is a healthy feeder-free and characterized human induced pluripotent stem (iPS) cell line. Cultured under xeno-free and defined conditions. The line is generated from healthy human fibroblasts with non-integrating Sendai virus vectors encoding the four Yamanaka factors, OCT4, SOX2, KLF4 and cMYC. The generated iPS cells are free from reprogramming vectors and their purity, karyotypic stability and pluripotent capacity is confirmed.

Generation of human iPS cell line CTL07-II from human fibroblasts, under defined and xeno-free conditions.

Human induced pluripotent stem (hiPS) cell lines CTRL-9-II and CTRL-10-I were derived from healthy monozygotic twin donors using non-integrating RNA based Sendai virus reprogramming and cultured in a xeno-free chemically defined condition. The established hiPS cell lines, CTRL-9-II and CTRL-10-I, are karyotypically normal, free from reprogramming vectors, display endogenously expression of pluripotency factors at levels similar to embryonic stem cells. The generated iPS cell lines demonstrate pluripotency by passing bioinformatics assay PluriTest and by embryonic body assay.

Article	Year
Biogrid--a microfluidic device for large-scale enzyme-free dissociation of stem cell aggregates. Lab on a chip\| PubMed ID: 21850297	2011
A Combination of Culture Conditions and Gene Expression Analysis Can Be Used to Investigate and Predict hES Cell Differentiation Potential towards Male Gonadal Cells. PloS one\| PubMed ID: 26630562	2015
Generation of human iPS cell line CTL07-II from human fibroblasts, under defined and xeno-free conditions. Stem cell research\| PubMed ID: 27789397	2016
Derivation of human iPS cell lines from monozygotic twins in defined and xeno free conditions. Stem cell research\| PubMed ID: 28395796	2017

Kelly Day

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