Generation of human organs in pigs via interspecies blastocyst complementation

Abstract

ContentsMore than eighteen years have passed since the first derivation of human embryonic stem cells (ESCs), but their clinical use is still met with several challenges, such as ethical concerns regarding the need of human embryos, tissue rejection after transplantation and tumour formation. The generation of human induced pluripotent stem cells (iPSCs) enables the access to patient-derived pluripotent stem cells (PSCs) and opens the door for personalized medicine as tissues/organs can potentially be generated from the same genetic background as the patient recipients, thus avoiding immune rejections or complication of immunosuppression strategies. In this regard, successful replacement, or augmentation, of the function of damaged tissue by patient-derived differentiated stem cells provides a promising cell replacement therapy for many devastating human diseases. Although human iPSCs can proliferate unlimitedly in culture and harbour the potential to generate all cell types in the adult body, currently, the functionality of differentiated cells is limited. An alternative strategy to realize the full potential of human iPSC for regenerative medicine is the in vivo tissue generation in large animal species via interspecies blastocyst complementation. As this technology is still in its infancy and there remains more questions than answers, thus in this review, we mainly focus the discussion on the conceptual framework, the emerging technologies and recent advances involved with interspecies blastocyst complementation, and will refer the readers to other more in-depth reviews on dynamic pluripotent stem cell states, genome editing and interspecies chimeras. Likewise, other emerging alternatives to combat the growing shortage of human organs, such as xenotransplantation or tissue engineering, topics that has been extensively reviewed, will not be covered here.

Functional Genomics via CRISPR–Cas

“…This pooled screen used an mCherry transcriptional reporter of IRE1α activation to facilitate cytometric isolation of cells with an activated unfolded protein response, thus enabling the enrichment of a unique phenotype separate from growth rate 78 . Utilizing similar methods researchers have been able to quantitate how genomic perturbations affect diverse cellular processes such as protein stability and the innate immune response 79,80 . However, FACS analysis is limited to predetermined targets that have fluorescently labeled antibodies commercially available, or to genetically encoded fluorescent reporter systems.…”

Genome Editing of Pigs for Agriculture and Biomedicine

“…In this section, we present an emerging cutting-edge technology, that is, growing of humanized organ in pigs or called xeno-generation; this technology is greatly promoted with the use of genome editing. Compared with directly modifying pig as an organ donor, xeno-generation includes interspecies blastocyst complementation combining donor (human) pluripotent stem cells and organogenesis-disabled hosts (pigs), allowing the enrichment of donor cells in a target organ to form a chimeric animal harboring a humanized target organ, which can be finally used for transplantation ( Wu et al, 2016 ). In this regard, organogenesis-disabled pigs can be simply realized by genome editing when the gene controlling the development of the target organ is identified.…”

A decade of experience with genetically tailored pig models for diabetes and metabolic research

“…More comprehensive reviews on these topics have been published recently ( Kemter et al., 2018 ; Kleinert et al., 2018 ; Renner et al., 2020 ). In addition, there are interesting attempts to generate human tissues in animal hosts ( Wu et al., 2017 ), which have been discussed elsewhere ( Wu et al., 2016a , b ; Suchy and Nakauchi, 2018 ; Suchy et al., 2018 ).…”