Ruttachuk Rungsiwiwut

Eighteen-Year Cryopreservation Does Not Negatively Affect the Pluripotency of Human Embryos: Evidence from Embryonic Stem Cell Derivation

Abstract Human embryonic stem (hES) cells are considered to be a potential source for the therapy of human diseases, drug screening, and the study of developmental biology. In the present study, we successfully derived hES cell lines from blastocysts developed from frozen and fresh embryos. Seventeen- to eighteen-year-old frozen embryos were thawed, cultured to the blastocyst stage, and induced to form hES cells using human foreskin fibroblasts. The Chula2.hES cell line and the Chula4.hES and Chula5.hES cell lines were derived from blastocysts developed from frozen and fresh embryos, respectively. The cell lines expressed pluripotent markers, including alkaline phosphatase (AP), Oct3/4, stage-specific embryonic antigen (SSEA)-4, and tumor recognition antigen (TRA)-1-60 and TRA-1-81 as detected with immunocytochemistry. The real-time polymerase chain reaction (RT-PCR) results showed that the cell lines expressed pluripotent genes, including OCT3/4, SOX2, NANOG, UTF, LIN28, REX1, NODAL, and E-Cadherin. In addition, the telomerase activities of the cell lines were higher than in the fibroblast cells. Moreover, the cell lines differentiated into all three germ layers both in vitro and in vivo. The cell lines had distinct identities, as revealed with DNA fingerprinting, and maintained their normal karyotype after a long-term culture. This study is the first to report the successful derivation of hES cell lines in Thailand and that frozen embryos maintained their pluripotency similar to fresh embryos, as shown by the success of hES cell derivation, even after years of cryopreservation. Therefore, embryos from prolonged cryopreservation could be an alternative source for embryonic stem cell research.

Generation of Mouse Embryonic Stem Cell Lines from Zona-Free Nuclear Transfer Embryos

Pluripotent stem cells would have great potential in cell therapies and drug development when genetically matched with the patient; thus, histocompatible cells could be used in transplantation therapy or as a source of patient-specific cells for drug testing. Pluripotent embryonic stem cells (ESCs)-generated via somatic cell nuclear transfer (SCNT) or parthenogenesis (pESC)-are potential sources of histocompatible cells and tissues for transplantation. Earlier studies used the piezoelectric microinjection (PEM) technique for nuclear transfer (NT) in mouse. No specific studies examined zona-free (ZF) NT as an alternative NT method to generate genetically matched ESCs of a nuclear donor. In this study, we compared the efficiency of nuclear transfer-derived ESC (ntESC) line establishment from ZF-NT, ZF-parthenogenetic (PGA), and ZF-fertilized embryos with that of the PEM-NT method. Different nuclei donor cells [cumulus, ESC, and mouse embryonic fibroblast (MEF)] were used and the efficiency of ntESC derivation was investigated, along with their in vitro characterization. The ZF-NT methods efficiency was higher than that of the PEM-NT using cumulus cells. When ESCs and cumulus cells were used as nuclear donor cells, they resulted in significantly higher ZF-NT-derived ntESC line establishment rates compared to MEF cells. In conclusion, the nuclear donor cell type significantly affected the efficiency of ntESC line establishment, and the ZF-NT method was efficient to establish pluripotent ntESC lines.

Report of the International Stem Cell Banking Initiative Workshop Activity: Current Hurdles and Progress in Seed-Stock Banking of Human Pluripotent Stem Cells.

This article summarizes the recent activity of the International Stem Cell Banking Initiative (ISCBI) held at the California Institute for Regenerative Medicine (CIRM) in California (June 26, 2016) and the Korean National Institutes for Health in Korea (October 19–20, 2016). Through the workshops, ISCBI is endeavoring to support a new paradigm for human medicine using pluripotent stem cells (hPSC) for cell therapies. Priority considerations for ISCBI include ensuring the safety and efficacy of a final cell therapy product and quality assured source materials, such as stem cells and primary donor cells. To these ends, ISCBI aims to promote global harmonization on quality and safety control of stem cells for research and the development of starting materials for cell therapies, with regular workshops involving hPSC banking centers, biologists, and regulatory bodies. Here, we provide a brief overview of two such recent activities, with summaries of key issues raised. Stem Cells Translational Medicine 2017;6:1956–1962

Tropism and Induction of Cytokines in Human Embryonic-Stem Cells-Derived Neural Progenitors upon Inoculation with Highly- Pathogenic Avian H5N1 Influenza Virus.

Central nervous system (CNS) dysfunction caused by neurovirulent influenza viruses is a dreaded complication of infection, and may play a role in some neurodegenerative conditions, such as Parkinson-like diseases and encephalitis lethargica. Although CNS infection by highly pathogenic H5N1 virus has been demonstrated, it is unknown whether H5N1 infects neural progenitor cells, nor whether such infection plays a role in the neuroinflammation and neurodegeneration. To pursue this question, we infected human neural progenitor cells (hNPCs) differentiated from human embryonic stem cells in vitro with H5N1 virus, and studied the resulting cytopathology, cytokine expression, and genes involved in the differentiation. Human embryonic stem cells (BG01) were maintained and differentiated into the neural progenitors, and then infected by H5N1 virus (A/Chicken/Thailand/CUK2/04) at a multiplicity of infection of 1. At 6, 24, 48, and 72 hours post-infection (hpi), cytopathic effects were observed. Then cells were characterized by immunofluorescence and electron microscopy, supernatants quantified for virus titers, and sampled cells studied for candidate genes.The hNPCs were susceptible to H5N1 virus infection as determined by morphological observation and immunofluorescence. The infection was characterized by a significant up-regulation of TNF-α gene expression, while expressions of IFN-α2, IFN-β1, IFN-γ and IL-6 remained unchanged compared to mock-infected controls. Moreover, H5N1 infection did not appear to alter expression of neuronal and astrocytic markers of hNPCs, such as β-III tubulin and GFAP, respectively. The results indicate that hNPCs support H5N1 virus infection and may play a role in the neuroinflammation during acute viral encephalitis.

Human Umbilical Cord Blood-Derived Serum for Culturing the Supportive Feeder Cells of Human Pluripotent Stem Cell Lines

Although human pluripotent stem cells (hPSCs) can proliferate robustly on the feeder-free culture system, genetic instability of hPSCs has been reported in such environment. Alternatively, feeder cells enable hPSCs to maintain their pluripotency. The feeder cells are usually grown in a culture medium containing fetal bovine serum (FBS) prior to coculture with hPSCs. The use of FBS might limit the clinical application of hPSCs. Recently, human cord blood-derived serum (hUCS) showed a positive effect on culture of mesenchymal stem cells. It is interesting to test whether hUCS can be used for culture of feeder cells of hPSCs. This study was aimed to replace FBS with hUCS for culturing the human foreskin fibroblasts (HFFs) prior to feeder cell preparation. The results showed that HFFs cultured in hUCS-containing medium (HFF-hUCS) displayed fibroblastic features, high proliferation rates, short population doubling times, and normal karyotypes after prolonged culture. Inactivated HFF-hUCS expressed important genes, including Activin A, FGF2, and TGFβ1, which have been implicated in the maintenance of hPSC pluripotency. Moreover, hPSC lines maintained pluripotency, differentiation capacities, and karyotypic stability after being cocultured for extended period with inactivated HFF-hUCS. Therefore, the results demonstrated the benefit of hUCS for hPSCs culture system.

The ROCK Inhibitor Y-26732 Enhances the Survival and Proliferation of Human Embryonic Stem Cell-Derived Neural Progenitor Cells upon Dissociation

Human neural progenitor cells (hNPCs) are the starting material required for neuronal subtype differentiation. Proliferation of hNPCs allows researchers to study the mechanistic complexities and microenvironments present during neural differentiation and to explore potential applications for hNPCs in cell therapies. The use of enzymatic dissociation during hNPC proliferation causes dissociation-induced apoptosis; therefore, in the present study, we examined the effect of the p-160-Rho-associated coiled-coil kinase (ROCK) inhibitor Y-26732 on dissociation-induced apoptosis of hNPCs. We generated hNPCs via embryoid body formation using serum-free culture medium supplemented with noggin. The established hNPCs were characterized and the effect of the ROCK inhibitor on hNPC dissociation was studied. We demonstrated that supplementation of the culture media with 10 μM Y-26732 efficiently reduced apoptosis of dissociated hNPCs; this supplementation was effective when the inhibitor was applied either at (i) 24 h before dissociation of the cells and at 24 h after plating the cells or (ii) at 24 h after plating of the cells only. In addition to reducing apoptosis, both supplementation conditions with Y-26732 enhanced the proliferation of dissociated hNPCs. Our findings provide the optimal time window for ROCK treatment of hNPC dissociation in respect to apoptosis and cell proliferation.

Comparative Analysis of Nuclear Transfer Embryo-Derived Mouse Embryonic Stem Cells. Part I: Cellular Characterization

Embryonic stem cells derived from nuclear transfer embryos (ntESCs) are particularly valuable for regenerative medicine, as they are a patient-specific and histocompatible cell source for the treatment of varying diseases. However, currently, little is known about their cellular and molecular profile. In the present study, in a mouse model different donor cell-derived ntESCs from various genetic backgrounds were compared with reference ESCs and analyzed comprehensively at the cellular level. A number of pluripotency marker genes were compared by flow cytometry and immunocytochemistry analysis. Significant differences at the protein level were observed for POU5F1, SOX2, FGF4, NANOG, and SSEA-1. However, such differences had no effect on in vitro cell differentiation and cell fate: derivatives of the three germ layers were detected in all ntESC lines. The neural and cardiac in vitro differentiation revealed minor differences between the cell lines, both at the mRNA and protein level. Karyotype analyses and cell growth studies did not reveal any significant variations. Despite some differences observed, the present study revealed that ntESC lines had similar differentiation competences compared to other ESCs. The results indicate that the observed differences may be related to the genotype rather than to the nuclear transfer technology.

Expression and Purification of Recombinant Human Basic Fibroblast Growth Factor Fusion Proteins and Their Uses in Human Stem Cell Culture.

To reduce the cost of cytokines and growth factors in stem cell research, a simple method for the production of soluble and biological active human basic fibroblast growth factor (hbFGF) fusion protein in Escherichia coli was established. Under optimal conditions, approximately 60-80 mg of >95% pure hbFGF fusion proteins (Trx-6xHis-hbFGF and 6xHis-hbFGF) were obtained from 1 liter of culture broth. The purified hbFGF proteins, both with and without the fusion tags, were biologically active, which was confirmed by their ability to stimulate proliferation of NIH3T3 cells. The fusion proteins also have the ability to support several culture passages of undifferentiated human embryonic stem cells and induce pluripotent stem cells. This paper describes a low-cost and uncomplicated method for the production and purification of biologically active hbFGF fusion proteins.

Triploid human embryonic stem cells derived from tripronuclear zygotes displayed pluripotency and trophoblast differentiation ability similar to the diploid human embryonic stem cells

Because the diploid human embryonic stem cells (hESCs) can be successfully derived from tripronuclear zygotes thus, they can serve as an alternative source of derivation of normal karyotype hESC lines. The aim of the present study was to compare the pluripotency and trophoblast differentiation ability of hESCs derived from tripronuclear zygotes and diploid hESCs. In the present study, a total of 20 tripronuclear zygotes were cultured; 8 zygotes developed to the blastocyst stage and 1 hESC line was generated. Unlike the previous studies, chromosomal correction of tripronuclear zygotes during derivation of hESCs did not occur. The established line carries 3 sets of chromosomes and showed a numerical aberration. Although the cell line displayed an abnormal chromosome number, it was found the cell line has been shown to be pluripotent with the ability to differentiate into 3 embryonic germ layers both in vitro and in vivo. The expression of X inactive specific transcript (XIST) in mid-passage (passage 42) of undifferentiated triploid hESCs was detected, indicating X chromosome inactivation of the cell line. Moreover, when this cell line was induced to differentiate toward the trophoblast lineage, morphological and functional trophoblast cells were observed, similar to the diploid hESC line.

Original article. Human dental pulp stem cells as a potential feeder layer for human embryonic stem cell culture

Abstract Background: Human embryonic stem (hES) cells are pluripotent, and can differentiate into three germ layers. Traditionally, cultures of hES cells are maintained in a system containing mouse embryonic fibroblasts as a feeder layer for support of undifferentiated growth. However, contamination by animal cells limits the use of hES cells. Objective: We evaluated the use of human dental pulp stem cells (hDPSCs) as a feeder layer for hES cell culture. It should be possible to obtain a new source of human mesenchymal stem cells for feeder cells to maintain undifferentiated growth of hES cells. Methods: hDPSCs from removed impacted wisdom teeth (third molars) were extracted, cultured, and characterized for mesenchymal stem cell properties. Furthermore, hDPSCs were used as a feeder layer for culturing Chula2 and Chula5 hES cell lines. Finally, hES cell lines grown on hDPSCs feeders were examined embryonic stem cell properties. Results: We found that hDPSCs, which have mesenchymal properties, can support undifferentiated growth of hES cell lines. After prolonged culture (passage 17), these hES cell lines still maintain ES cell properties including typical morphology seen in hES cells, the expression of pluripotency markers (Oct4, Sox2, Nanog, Rex1, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81), embryoid body formation and retention of a normal karyotype. Conclusion: hDPSCs, derived from the pulp tissue of impacted third molars, are a potential source of human feeder cells for the culture of undifferentiated hES cells.