Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.

3D bioprinting of tissues and organs

https://www.ics.uci.edu/~xhx/courses/references/Young_ES_regulator_cell06.pdf

Core transcriptional regulatory circuitry in human embryonic stem cells.

Functional expression cloning of nanog, a pluripotency sustaining factor in embryonic stem cells

https://www.cell.com/cell/pdf/S0092-8674(03)00393-3.pdf

The Homeoprotein Nanog Is Required for Maintenance of Pluripotency in Mouse Epiblast and ES Cells

Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte

We describe the derivation of pluripotent embryonic stem (ES) cells from human blastocysts. Two diploid ES cell lines have been cultivated in vitro for extended periods while maintaining expression of markers characteristic of pluripotent primate cells. Human ES cells express the transcription factor Oct-4, essential for development of pluripotential cells in the mouse. When grafted into SCID mice, both lines give rise to teratomas containing derivatives of all three embryonic germ layers. Both cell lines differentiate in vitro into extraembryonic and somatic cell lineages. Neural progenitor cells may be isolated from differentiating ES cell cultures and induced to form mature neurons. Embryonic stem cells provide a model to study early human embryology, an investigational tool for discovery of novel growth factors and medicines, and a potential source of cells for use in transplantation therapy.

Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro.

Previous reports have demonstrated the growth of undifferentiated human embryonic stem (HES) cells on mouse embryonic fibroblast (MEF) feeders and on laminin- or Matrigel-coated plastic surfaces supplemented with MEF-conditioned medium. These xenosupport systems run the risk of cross-transfer of animal pathogens from the animal feeder, matrix, or conditioned medium to the HES cells, thus compromising later clinical application. Here we show that human fetal and adult fibroblast feeders support prolonged undifferentiated HES cell growth of existing cell lines and are superior to cell-free matrices (collagen I, human extracellular matrix, Matrigel, and laminin) supplemented with human or MEF feeder-conditioned medium. Additionally, we report the derivation and establishment of a new HES cell line in completely animal-free conditions. Like HES cells cultured on MEF feeders, the HES cells grown on human feeders had normal karyotypes, tested positive for alkaline phosphatase activity, expressed Oct-4 and cell surface markers including SSEA-3, SSEA-4, Tra 1-60, and GCTM-2, formed teratomas in severely combined immunodeficient (SCID) mice, and retained all key morphological characteristics. Human feeder#150;supported HES cells should provide a safer alternative to existing HES cell lines in therapeutic applications.

Human feeders support prolonged undifferentiated growth of human inner cell masses and embryonic stem cells.

Human embryonic stem (ES) cell lines that have the ability to self-renew and differentiate into specific cell types have been established. The molecular mechanisms for self-renewal and differentiation, however, are poorly understood. We determined the transcriptome profiles for two proprietary human ES cell lines (HES3 and HES4, ES Cell International), and compared them with murine ES cells and other human tissues. Human and mouse ES cells appear to share a number of expressed gene products although there are numerous notable differences, including an inactive leukemia inhibitory factor pathway and the high preponderance of several important genes like POU5F1 and SOX2 in human ES cells. We have established a list of genes comprised of known ES-specific genes and new candidates that can serve as markers for human ES cells and may also contribute to the "stemness" phenotype. Of particular interest was the downregulation of DNMT3B and LIN28 mRNAs during ES cell differentiation. The overlapping similarities and differences in gene expression profiles of human and mouse ES cells provide a foundation for a detailed and concerted dissection of the molecular and cellular mechanisms governing their pluripotency, directed differentiation into specific cell types, and extended ability for self-renewal.

https://stemcellsjournals.onlinelibrary.wiley.com/doi/pdf/10.1634/stemcells.22-1-51

The Transcriptome Profile of Human Embryonic Stem Cells as Defined by SAGE

http://cv2i.org/wp-content/uploads/2012/09/Rangappa_AnnthroSurg_75_775_20031.pdf

Transformation of adult mesenchymal stem cells isolated from the fatty tissue into cardiomyocytes.

Human embryonic stem (hES) cells are typically derived and serially propagated on inactivated murine embryonic fibroblast (MEF) feeders The use of MEFs and other components of animal origin in the culture media for hES cell support substantially elevates the risk of contaminating these cell lines with infectious agents of animal origin thereby severely limiting their potential for clinical application We have previously shown that it is possible to derive and establish new hES cell lines in a xeno-free culture system using human fetal muscle fibroblast feeders In this report, we have comparatively evaluated a panel of 11 different human adult, fetal, and neonatal feeders for hES cell support and have ranked them as supportive and non-supportive We report that two adult skin fibroblast cell lines established in-house from abdominal skin biopsies supported prolonged undifferentiated hES cell growth for over 30 weekly passages in culture Furthermore, hES cell lines cultured on adult skin fibroblast feeders retain hES cell morphology and remain pluripotent Also, differences in feeder support exist between human cell types and sources The use of human adult skin feeders is convenient for hES cell support given the ease of obtaining skin biopsies

https://stemcellsjournals.onlinelibrary.wiley.com/doi/pdf/10.1634/stemcells.21-5-546

Ariff Bongso

Papers

Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro.

Human feeders support prolonged undifferentiated growth of human inner cell masses and embryonic stem cells.

The Transcriptome Profile of Human Embryonic Stem Cells as Defined by SAGE

Transformation of adult mesenchymal stem cells isolated from the fatty tissue into cardiomyocytes.

Comparative Evaluation of Various Human Feeders for Prolonged Undifferentiated Growth of Human Embryonic Stem Cells