scholarly journals Engineered human induced pluripotent cells enable genetic code expansion in brain organoids

2021 ◽  
Author(s):  
Lea van Husen ◽  
Anna Maria Katsori ◽  
Birthe Meineke ◽  
Lars O Tjernberg ◽  
Sophia Schedin-Weiss ◽  
...  

Human induced pluripotent stem cell (hiPSC) technology has revolutionized human biology. A wide range of cell types and tissue models can be derived from hiPSCs to study complex human diseases. Here, we use PiggyBac mediated transgenesis to engineer hiPSCs with an expanded genetic code. We demonstrate that genomic integration of expression cassettes for a pyrrolysyl-tRNA synthetase (PylRS), pyrrolysyl-tRNA (PylT) and the target protein of interest enables site-specific incorporation of a non-canonical amino acid (ncAA) in response to amber stop codons. Neural stem cells, neurons and brain organoids derived from the engineered hiPSCs continue to express the amber suppression machinery and produce ncAA-bearing reporter. The incorporated ncAA can serve as a minimal bioorthogonal handle for further modifications by labeling with fluorescent dyes. Site-directed ncAA mutagenesis will open a wide range of applications to probe and manipulate proteins in brain organoids and other hiPSC-derived cell types and complex tissue models.

ChemBioChem ◽  
2021 ◽  
Author(s):  
Lea S. Husen ◽  
Anna‐Maria Katsori ◽  
Birthe Meineke ◽  
Lars O. Tjernberg ◽  
Sophia Schedin‐Weiss ◽  
...  

2014 ◽  
Author(s):  
Irene Gallego Romero ◽  
Bryan J Pavlovic ◽  
Irene Hernando-Herraez ◽  
Nicholas E Banovich ◽  
Courtney L Kagan ◽  
...  

Comparative genomics studies in primates are extremely restricted because we only have access to a few types of cell lines from non-human apes and to a limited collection of frozen tissues. In order to gain better insight into regulatory processes that underlie variation in complex phenotypes, we must have access to faithful model systems for a wide range of tissues and cell types. To facilitate this, we have generated a panel of 7 fully characterized chimpanzee (Pan troglodytes) induced pluripotent stem cell (iPSC) lines derived from fibroblasts of healthy donors. All lines appear to be free of integration from exogenous reprogramming vectors, can be maintained using standard iPSC culture techniques, and have proliferative and differentiation potential similar to human and mouse lines. To begin demonstrating the utility of comparative iPSC panels, we collected RNA sequencing data and methylation profiles from the chimpanzee iPSCs and their corresponding fibroblast precursors, as well as from 7 human iPSCs and their precursors, which were of multiple cell type and population origins. Overall, we observed much less regulatory variation within species in the iPSCs than in the somatic precursors, indicating that the reprogramming process has erased many of the differences observed between somatic cells of different origins. We identified 4,918 differentially expressed genes and 3,598 differentially methylated regions between iPSCs of the two species, many of which are novel inter-species differences that were not observed between the somatic cells of the two species. Our panel will help realise the potential of iPSCs in primate studies, and in combination with genomic technologies, transform studies of comparative evolution.


ChemBioChem ◽  
2021 ◽  
Author(s):  
Lea S. van Husen ◽  
Anna-Maria Katasori ◽  
Birthe Meineke ◽  
Lars O. Tjernberg ◽  
Sophia Schedin-Weiss ◽  
...  

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Irene Gallego Romero ◽  
Bryan J Pavlovic ◽  
Irene Hernando-Herraez ◽  
Xiang Zhou ◽  
Michelle C Ward ◽  
...  

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.


2018 ◽  
Vol 115 (35) ◽  
pp. E8228-E8235 ◽  
Author(s):  
Taisuke Kanaji ◽  
My-Nuong Vo ◽  
Sachiko Kanaji ◽  
Alessandro Zarpellon ◽  
Ryan Shapiro ◽  
...  

New mechanisms behind blood cell formation continue to be uncovered, with therapeutic approaches for hematological diseases being of great interest. Here we report an enzyme in protein synthesis, known for cell-based activities beyond translation, is a factor inducing megakaryocyte-biased hematopoiesis, most likely under stress conditions. We show an activated form of tyrosyl-tRNA synthetase (YRSACT), prepared either by rationally designed mutagenesis or alternative splicing, induces expansion of a previously unrecognized high-ploidy Sca-1+ megakaryocyte population capable of accelerating platelet replenishment after depletion. Moreover, YRSACT targets monocytic cells to induce secretion of transacting cytokines that enhance megakaryocyte expansion stimulating the Toll-like receptor/MyD88 pathway. Platelet replenishment by YRSACT is independent of thrombopoietin (TPO), as evidenced by expansion of the megakaryocytes from induced pluripotent stem cell-derived hematopoietic stem cells from a patient deficient in TPO signaling. We suggest megakaryocyte-biased hematopoiesis induced by YRSACT offers new approaches for treating thrombocytopenia, boosting yields from cell-culture production of platelet concentrates for transfusion, and bridging therapy for hematopoietic stem cell transplantation.


Author(s):  
Elliot W. Swartz ◽  
Greg Shintani ◽  
Jijun Wan ◽  
Joseph S. Maffei ◽  
Sarah H. Wang ◽  
...  

SummaryThe failure of the neuromuscular junction (NMJ) is a key component of degenerative neuromuscular disease, yet how NMJs degenerate in disease is unclear. Human induced pluripotent stem cells (hiPSCs) offer the ability to model disease via differentiation toward affected cell types, however, the re-creation of an in vitro neuromuscular system has proven challenging. Here we present a scalable, all-hiPSC-derived co-culture system composed of independently derived spinal motor neurons (MNs) and skeletal myotubes (sKM). In a model of C9orf72-associated disease, co-cultures form functional NMJs that can be manipulated through optical stimulation, eliciting muscle contraction and measurable calcium flux in innervated sKM. Furthermore, co-cultures grown on multi-electrode arrays (MEAs) permit the pharmacological interrogation of neuromuscular physiology. Utilization of this co-culture model as a tunable, patient-derived system may offer significant insights into NMJ formation, maturation, repair, or pathogenic mechanisms that underlie NMJ dysfunction in disease.


2021 ◽  
Author(s):  
Zhengyu Ouyang ◽  
Nathanael Bourgeois ◽  
Eugenia Lyashenko ◽  
Paige Cundiff ◽  
Patrick F Cullen ◽  
...  

Induced pluripotent stem cell (iPSC) derived cell types are increasingly employed as in vitro model systems for drug discovery. For these studies to be meaningful, it is important to understand the reproducibility of the iPSC-derived cultures and their similarity to equivalent endogenous cell types. Single-cell and single-nucleus RNA sequencing (RNA-seq) are useful to gain such understanding, but they are expensive and time consuming, while bulk RNA-seq data can be generated quicker and at lower cost. In silico cell type decomposition is an efficient, inexpensive, and convenient alternative that can leverage bulk RNA-seq to derive more fine-grained information about these cultures. We developed CellMap, a computational tool that derives cell type profiles from publicly available single-cell and single-nucleus datasets to infer cell types in bulk RNA-seq data from iPSC-derived cell lines.


2015 ◽  
Vol 370 (1680) ◽  
pp. 20140367 ◽  
Author(s):  
Mari Ohnuki ◽  
Kazutoshi Takahashi

Growing old is our destiny. However, the mature differentiated cells making up our body can be rejuvenated to an embryo-like fate called pluripotency which is an ability to differentiate into all cell types by enforced expression of defined transcription factors. The discovery of this induced pluripotent stem cell (iPSC) technology has opened up unprecedented opportunities in regenerative medicine, disease modelling and drug discovery. In this review, we introduce the applications and future perspectives of human iPSCs and we also show how iPSC technology has evolved along the way.


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