Proteome analysis of human embryonic stem cells organelles.

As the functions of proteins are associated with their cellular localization, the comprehensive sub-cellular proteome knowledge of human embryonic stem cells (hESCs) is indispensable for ensuring a therapeutic effect. Here, we have utilized a sub-cellular proteomics approach to analyze the localization of proteins in the nucleus, mitochondria, crude membrane, cytoplasm, heavy and light microsomes. Out of 2002 reproducibly identified proteins, we detected 762 proteins in a single organelle whereas 160 proteins were found in all sub-cellular fractions. We verified the localization of identified proteins through databases and discussed the consistency of the obtained results. With regards to the ambiguity in the definition of a membrane protein, we tried to clearly define the plasma membrane, peripheral membrane and membrane proteins by annotation of these proteins in databases, along with predictions of transmembrane helices. Among ten enriched signaling pathways highlighted in our results, non-canonical Wnt signaling were analyzed in greater detail. The functions of three novel hESC membrane proteins (ERBB4, GGT1 and ZDHHC13) have been assessed in terms of pluripotency. Our report is the most comprehensive for organellar proteomics of hESCs. SIGNIFICANCE: Mass spectrometric identification of proteins using a TripleTOF 5600 from nucleus, mitochondria, crude membrane, cytoplasm, heavy and light microsomal fractions highlighted the significance of the non-canonical Wnt signaling in human embryonic stem cells.

A Universal and Robust Integrated Platform for the Scalable Production of Human Cardiomyocytes From Pluripotent Stem Cells.

UNLABELLED: Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs), in conjunction with the promising outcomes from preclinical and clinical studies, have raised new hopes for cardiac cell therapy. We report the development of a scalable, robust, and integrated differentiation platform for large-scale production of hPSC-CM aggregates in a stirred suspension bioreactor as a single-unit operation. Precise modulation of the differentiation process by small molecule activation of WNT signaling, followed by inactivation of transforming growth factor-ß and WNT signaling and activation of sonic hedgehog signaling in hPSCs as size-controlled aggregates led to the generation of approximately 100% beating CM spheroids containing virtually pure (∼90%) CMs in 10 days. Moreover, the developed differentiation strategy was universal, as demonstrated by testing multiple hPSC lines (5 human embryonic stem cell and 4 human inducible PSC lines) without cell sorting or selection. The produced hPSC-CMs successfully expressed canonical lineage-specific markers and showed high functionality, as demonstrated by microelectrode array and electrophysiology tests. This robust and universal platform could become a valuable tool for the mass production of functional hPSC-CMs as a prerequisite for realizing their promising potential for therapeutic and industrial applications, including drug discovery and toxicity assays. SIGNIFICANCE: Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) and the development of novel cell therapy strategies using hPSC-CMs (e.g., cardiac patches) in conjunction with promising preclinical and clinical studies, have raised new hopes for patients with end-stage cardiovascular disease, which remains the leading cause of morbidity and mortality globally. In this study, a simplified, scalable, robust, and integrated differentiation platform was developed to generate clinical grade hPSC-CMs as cell aggregates under chemically defined culture conditions. This approach resulted in approximately 100% beating CM spheroids with virtually pure (∼90%) functional cardiomyocytes in 10 days from multiple hPSC lines. This universal and robust bioprocessing platform can provide sufficient numbers of hPSC-CMs for companies developing regenerative medicine technologies to rescue, replace, and help repair damaged heart tissues and for pharmaceutical companies developing advanced biologics and drugs for regeneration of lost heart tissue using high-throughput technologies. It is believed that this technology can expedite clinical progress in these areas to achieve a meaningful impact on improving clinical outcomes, cost of care, and quality of life for those patients disabled and experiencing heart disease.

Long-term maintenance of undifferentiated human embryonic and induced pluripotent stem cells in suspension.

Traditionally, undifferentiated pluripotent human embryonic and induced pluripotent stem cells (hESCs and hiPSCs) have been expanded as monolayer colonies in adhesion culture, both in the presence or absence of feeder cells. However, the use of pluripotent stem cells poses the need to scale-up current culture methods. Herein, we present the cultivation of 2 hESC lines (Royan H5 and Royan H6) and 2 hiPSC lines (hiPSC1 and hiPSC4) as carrier-free suspension aggregates for an extended period of time. The cells proliferated over multiple passages kept a stable karyotype, which successfully maintained an undifferentiated state and pluripotency, as determined by marker expressions in addition to in vitro spontaneous and directed differentiation. Additionally, these cells can be easily frozen and thawed without losing their proliferation, karyotype stability, and developmental potential. Transcriptome analysis of the 3 lines revealed that the adherent culture condition was nearly identical to the suspension culture in Royan H5 and hiPSC1, but not in Royan H6. It remains unclear whether this observation at the transcript level is biologically significant. In comparison with recent reports, our study presents a low-cost procedure for long-term suspension expansion of hESCs and hiPSCs with the capability of freeze/thawing, karyotype stability, and pluripotency. Our results will pave the way for scaled up expansion and controlled differentiation of hESCs and hiPSCs needed for cell therapy, research, and industrial applications in a bioreactor culture system.