Comparative genomics studies in primates are restricted due to our limited access to samples. In order to gain better insight into the genetic processes that underlie variation in complex phenotypes in primates, we must have access to faithful model systems for a wide range of cell types. To facilitate this, we generated a panel of 7 fully characterized chimpanzee induced pluripotent stem cell (iPSC) lines derived from healthy donors. To demonstrate the utility of comparative iPSC panels, we collected RNA-sequencing and DNA methylation data from the chimpanzee iPSCs and the corresponding fibroblast lines, as well as from 7 human iPSCs and their source lines, which encompass multiple populations and cell types. We observe much less within-species variation in iPSCs than in somatic cells, indicating the reprogramming process erases many inter-individual differences. The low within-species regulatory variation in iPSCs allowed us to identify many novel inter-species regulatory differences of small magnitude.DOI: http://dx.doi.org/10.7554/eLife.07103.001

ZOO Dvůr Kr alov e, Dvůr Kr alov e nad Labem, Czech RepublicWith only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name "Conservation by Cellular Technologies." The outcome of this meeting and the proposed road map that, if successfully implemented, would ultimately lead to a self-sustaining population of an extremely endangered species are outlined here. The ideas discussed here, while centered on the northern white rhinoceros, are equally applicable, after proper adjustments, to other mammals on the brink of extinction. Through implementation of these ideas we hope to establish the Conflicts of interest: None.Oliver A. Ryder and Thomas B. Hildebrandt are of equal seniority.Co-authors, other than first and the two senior authors, are listed by alphabetical order.

For some highly endangered species there are too few reproductively capable animals to maintain adequate genetic diversity, and extraordinary measures are necessary to prevent extinction. We report generation of induced pluripotent stem cells (iPSCs) from two endangered species: a primate, the drill, Mandrillus leucophaeus and the nearly extinct northern white rhinoceros, Ceratotherium simum cottoni. iPSCs may eventually facilitate reintroduction of genetic material into breeding populations.

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Industrialization of stem-cell based therapies requires innovative solutions to close the gap between research and commercialization. Scalable cell production platforms are needed to reliably deliver the cell quantities needed during the various stages of development and commercial supply. Human pluripotent stem cells (hPSCs) are a key source material for generating therapeutic cell types. We have developed a closed, automated and scalable stirred tank bioreactor platform, capable of sustaining high fold expansion of hPSCs. Such a platform could facilitate the in-process monitoring and integration of online monitoring systems, leading to significantly reduced labor requirements and contamination risk. hPSCs are expanded in a controlled bioreactor using perfused xeno-free media. Cell harvest and concentration are performed in closed steps. The hPSCs can be cryopreserved to generate a bank of cells, or further processed as needed. Cryopreserved cells can be thawed into a two-dimensional (2D) tissue culture platform or a three-dimensional (3D) bioreactor to initiate a new expansion phase, or be differentiated to the clinically relevant cell type. The expanded hPSCs express hPSC-specific markers, have a normal karyotype and the ability to differentiate to the cells of the three germ layers. This end-to-end platform allows a large scale expansion of high quality hPSCs that can support the required cell demand for various clinical indications.Int. J. Mol. Sci. 2020, 21, 89 2 of 29 recapitulate in vivo conditions. To replace the number of cells lost during a myocardial infarction, for example, approximately 1 × 10 9 cells are required per patient dose [7].Given that 2D-based cell culture platforms are nonscalable with minimal capacity for expansion, achieving high cell densities in a 2D system would involve costly arrangements including extensive manual effort, laboratory space and personnel. These platforms also often do not possess adequate systems to control or monitor parameters, such as the production of key metabolites by hiPSCs in culture. Moreover, iPSC-derived cardiomyocytes remain phenotypically immature [8], despite a number of studies demonstrating enhanced maturation through the modulation of existing methodologies [9][10][11][12][13].Recent innovations in suspension culture systems provide robust, controlled and scalable platforms beyond conventional 2D approaches, which can be translated to current Good Manufacturing Practice (cGMP) compliant processes [14][15][16]. A number of studies have demonstrated the feasibility of hPSC expansion in suspension cultures using aggregate [14,16,17] and microcarrier (MC)-based [18][19][20] three dimensional (3D) culture systems. Aggregate-based 3D culture provides a more physiologically relevant microenvironment, but has been shown not only to require the small molecule, Y27632, for the survival of hPSCs [15], but also sequential passaging to achieve high fold expansion [21]. Not without its own advantages, microcarrier-based culture systems facilitate a larger surface...