Unchain My Heart: Integrins at the Basis of iPSC Cardiomyocyte Differentiation

The cellular response to the extracellular matrix (ECM) microenvironment mediated by integrin adhesion is of fundamental importance, in both developmental and pathological processes. In particular, mechanotransduction is of growing importance in groundbreaking cellular models such as induced pluripotent stem cells (iPSC), since this process may strongly influence cell fate and, thus, augment the precision of differentiation into specific cell types, e.g., cardiomyocytes. The decryption of the cellular machinery starting from ECM sensing to iPSC differentiation calls for new in vitro methods. Conveniently, engineered biomaterials activating controlled integrin-mediated responses through chemical, physical, and geometrical designs are key to resolving this issue and could foster clinical translation of optimized iPSC-based technology. This review introduces the main integrin-dependent mechanisms and signalling pathways involved in mechanotransduction. Special consideration is given to the integrin-iPSC linkage signalling chain in the cardiovascular field, focusing on biomaterial-based in vitro models to evaluate the relevance of this process in iPSC differentiation into cardiomyocytes.

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Utilising Induced Pluripotent Stem Cells in Neurodegenerative Disease Research: Focus on Glia

International Journal of Molecular Sciences ◽

10.3390/ijms22094334 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4334

Author(s):

Katrina Albert ◽

Jonna Niskanen ◽

Sara Kälvälä ◽

Šárka Lehtonen

Keyword(s):

Stem Cells ◽

Neurodegenerative Diseases ◽

Neurodegenerative Disease ◽

Induced Pluripotent Stem Cells ◽

Glial Cells ◽

Pluripotent Stem Cells ◽

Cell Types ◽

Human Ipscs ◽

Induced Pluripotent

Induced pluripotent stem cells (iPSCs) are a self-renewable pool of cells derived from an organism’s somatic cells. These can then be programmed to other cell types, including neurons. Use of iPSCs in research has been two-fold as they have been used for human disease modelling as well as for the possibility to generate new therapies. Particularly in complex human diseases, such as neurodegenerative diseases, iPSCs can give advantages over traditional animal models in that they more accurately represent the human genome. Additionally, patient-derived cells can be modified using gene editing technology and further transplanted to the brain. Glial cells have recently become important avenues of research in the field of neurodegenerative diseases, for example, in Alzheimer’s disease and Parkinson’s disease. This review focuses on using glial cells (astrocytes, microglia, and oligodendrocytes) derived from human iPSCs in order to give a better understanding of how these cells contribute to neurodegenerative disease pathology. Using glia iPSCs in in vitro cell culture, cerebral organoids, and intracranial transplantation may give us future insight into both more accurate models and disease-modifying therapies.

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Advances and Challenges in Kidney Organoids

Current Stem Cell Research & Therapy ◽

10.2174/1574888x16666210804113626 ◽

2021 ◽

Vol 16 ◽

Author(s):

Vikram Sabapathy ◽

Gabrielle Costlow ◽

Rajkumar Venkatadri ◽

Murat Dogan ◽

Sanjay Kumar ◽

...

Keyword(s):

Cell Fate ◽

Pluripotent Stem Cells ◽

Molecular Mechanisms ◽

Cell Types ◽

Complex Structures ◽

Cell Culture Systems ◽

Epigenetic Signatures ◽

Kidney Organoids

: The advent of organoids has renewed researcher's interest in in vitro cell culture systems. A wide variety of protocols, primarily utilizing pluripotent stem cells, are under development to improve organoid generation to mimic organ development. The complexity of organoids generated is greatly influenced based on the method used. Understanding the process of kidney organoid formation gives developmental insights into how renal cells form, mature, and interact with the adjacent cells to form specific spatiotemporal structural patterns. This knowledge can bridge the gaps in understanding in vivo renal developmental processes. Evaluating genetic and epigenetic signatures in specialized cell types can help interpret the molecular mechanisms governing cell fate. In addition, development in single-cell RNA sequencing and 3D bioprinting and microfluidic technologies has led to better identification and understanding of a variety of cell types during differentiation and designing of complex structures to mimic the conditions in vivo. While several reviews have highlighted the application of kidney organoids, there is no comprehensive review of various methodologies specifically focusing on the kidney organoids. This review summarizes the updated differentiation methodologies, applications, and challenges associated with kidney organoids. Here we have comprehensively collated all the different variables influencing the organoid generation.

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Vertebrate retinal ganglion cells are selected from competent progenitors by the action of Notch

Development ◽

10.1242/dev.121.11.3637 ◽

1995 ◽

Vol 121 (11) ◽

pp. 3637-3650 ◽

Cited By ~ 33

Author(s):

C.P. Austin ◽

D.E. Feldman ◽

J.A. Ida ◽

C.L. Cepko

Keyword(s):

Cell Fate ◽

Ganglion Cells ◽

Notch Pathway ◽

Cell Types ◽

Projection Neurons ◽

Specific Cell ◽

Vitro Assay ◽

Notch Activity

The first cells generated during development of the vertebrate retina are the ganglion cells, the projection neurons of the retina. Although they are one of the most intensively studied cell types within the central nervous system, little is known of the mechanisms that determine ganglion cell fate. We demonstrate that ganglion cells are selected from a large group of competent progenitors that comprise the majority of the early embryonic retina and that differentiation within this group is regulated by Notch. Notch activity in vivo was diminished using antisense oligonucleotides or augmented using a retrovirally transduced constitutively active allele of Notch. The number of ganglion cells produced was inversely related to the level of Notch activity. In addition, the Notch ligand Delta inhibited retinal progenitors from differentiating as ganglion cells to the same degree as did activated Notch in an in vitro assay. These results suggest a conserved strategy for neurogenesis in the retina and describe a versatile in vitro and in vivo system with which to examine the action of the Notch pathway in a specific cell fate decision in a vertebrate.

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Induced pluripotent stem cells-derived neurons from patients with Friedreich ataxia exhibit differential sensitivity to resveratrol and nicotinamide

Scientific Reports ◽

10.1038/s41598-019-49870-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 5

Author(s):

Pauline Georges ◽

Maria-Gabriela Boza-Moran ◽

Jacqueline Gide ◽

Georges Arielle Pêche ◽

Benjamin Forêt ◽

...

Keyword(s):

Stem Cells ◽

Drug Discovery ◽

Pluripotent Stem Cells ◽

Friedreich Ataxia ◽

Cell Types ◽

Differential Sensitivity ◽

Human Ipscs ◽

Induced Pluripotent ◽

Species Specific

Abstract Translation of pharmacological results from in vitro cell testing to clinical trials is challenging. One of the causes that may underlie these discrepant results is the lack of the phenotypic or species-specific relevance of the tested cells; today, this lack of relevance may be reduced by relying on cells differentiated from human pluripotent stem cells. To analyse the benefits provided by this approach, we chose to focus on Friedreich ataxia, a neurodegenerative condition for which the recent clinical testing of two compounds was not successful. These compounds, namely, resveratrol and nicotinamide, were selected because they had been shown to stimulate the expression of frataxin in fibroblasts and lymphoblastoid cells. Our results indicated that these compounds failed to do so in iPSC-derived neurons generated from two patients with Friedreich ataxia. By comparing the effects of both molecules on different cell types that may be considered to be non-relevant for the disease, such as fibroblasts, or more relevant to the disease, such as neurons differentiated from iPSCs, a differential response was observed; this response suggests the importance of developing more predictive in vitro systems for drug discovery. Our results demonstrate the value of utilizing human iPSCs early in drug discovery to improve translational predictability.

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Development of a Personalized Intestinal Fibrosis Model Using Human Intestinal Organoids Derived From Induced Pluripotent Stem Cells

Inflammatory Bowel Diseases ◽

10.1093/ibd/izab292 ◽

2021 ◽

Author(s):

Hannah Q Estrada ◽

Shachi Patel ◽

Shervin Rabizadeh ◽

David Casero ◽

Stephan R Targan ◽

...

Keyword(s):

Stem Cells ◽

Induced Pluripotent Stem Cells ◽

Rna Sequencing ◽

Pluripotent Stem Cells ◽

Cell Types ◽

Mesenchymal Cells ◽

Sequencing Analysis ◽

Intestinal Fibrosis ◽

Induced Pluripotent

Abstract Background Intestinal fibrosis is a serious complication of Crohn’s disease. Numerous cell types including intestinal epithelial and mesenchymal cells are implicated in this process, yet studies are hampered by the lack of personalized in vitro models. Human intestinal organoids (HIOs) derived from induced pluripotent stem cells (iPSCs) contain these cell types, and our goal was to determine the feasibility of utilizing these to develop a personalized intestinal fibrosis model. Methods iPSCs from 2 control individuals and 2 very early onset inflammatory bowel disease patients with stricturing complications were obtained and directed to form HIOs. Purified populations of epithelial and mesenchymal cells were derived from HIOs, and both types were treated with the profibrogenic cytokine transforming growth factor β (TGFβ). Quantitative polymerase chain reaction and RNA sequencing analysis were used to assay their responses. Results In iPSC-derived mesenchymal cells, there was a significant increase in the expression of profibrotic genes (Col1a1, Col5a1, and TIMP1) in response to TGFβ. RNA sequencing analysis identified further profibrotic genes and demonstrated differential responses to this cytokine in each of the 4 lines. Increases in profibrotic gene expression (Col1a1, FN, TIMP1) along with genes associated with epithelial-mesenchymal transition (vimentin and N-cadherin) were observed in TGFβ -treated epithelial cells. Conclusions We demonstrate the feasibility of utilizing iPSC-HIO technology to model intestinal fibrotic responses in vitro. This now permits the generation of near unlimited quantities of patient-specific cells that could be used to reveal cell- and environmental-specific mechanisms underpinning intestinal fibrosis.

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Dot1L methyltransferase activity is a barrier to acquisition of pluripotency but not transdifferentiation

10.1101/835413 ◽

2019 ◽

Cited By ~ 1

Author(s):

Coral K. Wille ◽

Rupa Sridharan

Keyword(s):

Stem Cells ◽

Cell Fate ◽

Pluripotent Stem Cells ◽

Somatic Cells ◽

Cell Types ◽

Transcriptional Elongation ◽

Mrna Levels ◽

Mesenchymal To Epithelial Transition ◽

Ipsc Generation ◽

Induced Pluripotent

ABSTRACTThe ability of pluripotent stem cells to be poised to differentiate into any somatic cell type is partly derived from a unique chromatin structure that is depleted for transcriptional elongation associated epigenetic modifications, primarily H3K79 methylation. Inhibiting the H3K79 methyltransferase, Dot1L, increases the efficiency of reprogramming somatic cells to induced pluripotent stem cells (iPSCs) most potently at the mid-point of the process. Surprisingly, despite the enrichment of H3K79me2 on thousands of actively transcribed genes, Dot1L inhibition (Dot1Li) results in few changes in steady state mRNA levels during reprogramming. Dot1Li spuriously upregulates genes not involved in pluripotency and does not shutdown the somatic program. Depletion of the few genes that are downregulated, such as Nfix, enhances reprogramming efficiency in cooperation with Dot1Li. Contrary to the prevalent view, Dot1Li promotes iPSC generation beyond early phases of reprogramming such as the mesenchymal to epithelial transition and from already epithelial cell types including keratinocytes. Significantly, Dot1L inhibition does not enhance lineage conversion to neurons or muscle cells. Taken together, our results indicate that H3K79me is not a universal barrier of cell fate transitions but specifically protects somatic cells from reverting to the pluripotent state.

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Generation of Sheep Induced Pluripotent Stem Cells With Defined DOX-Inducible Transcription Factors via piggyBac Transposition

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.785055 ◽

2021 ◽

Vol 9 ◽

Author(s):

Moning Liu ◽

Lixia Zhao ◽

Zixin Wang ◽

Hong Su ◽

Tong Wang ◽

...

Keyword(s):

Stem Cells ◽

Induced Pluripotent Stem Cells ◽

Pluripotent Stem Cells ◽

Embryonic Stem ◽

Cell Types ◽

T Antigen ◽

Sv40 Large T Antigen ◽

Adult Individual ◽

Induced Pluripotent

Pluripotent stem cells (PSCs) have the potential to differentiate to all cell types of an adult individual and are useful for studying mammalian development. Establishing induced pluripotent stem cells (iPSCs) capable of expressing pluripotent genes and differentiating to three germ layers will not only help to explain the mechanisms underlying somatic reprogramming but also lay the foundation for the establishment of sheep embryonic stem cells (ESCs) in vitro. In this study, sheep somatic cells were reprogrammed in vitro into sheep iPSCs with stable morphology, pluripotent marker expression, and differentiation ability, delivered by piggyBac transposon system with eight doxycycline (DOX)-inducible exogenous reprogramming factors: bovine OCT4, SOX2, KLF4, cMYC, porcine NANOG, human LIN28, SV40 large T antigen, and human TERT. Sheep iPSCs exhibited a chimeric contribution to the early blastocysts of sheep and mice and E6.5 mouse embryos in vitro. A transcriptome analysis revealed the pluripotent characteristics of somatic reprogramming and insights into sheep iPSCs. This study provides an ideal experimental material for further study of the construction of totipotent ESCs in sheep.

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Generation of defined neural populations from pluripotent stem cells

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2017.0214 ◽

2018 ◽

Vol 373 (1750) ◽

pp. 20170214 ◽

Cited By ~ 7

Author(s):

Sarah F. McComish ◽

Maeve A. Caldwell

Keyword(s):

Stem Cells ◽

Pluripotent Stem Cells ◽

Embryonic Stem ◽

Cell Types ◽

Disease Modelling ◽

Human Neural Stem Cells ◽

Neural Populations ◽

Human Disorders ◽

Induced Pluripotent

Effective and efficient generation of human neural stem cells and subsequently functional neural populations from pluripotent stem cells has facilitated advancements in the study of human development and disease modelling. This review will discuss the established protocols for the generation of defined neural populations including regionalized neurons and astrocytes, oligodendrocytes and microglia. Early protocols were established in embryonic stem cells (ESC) but the discovery of induced pluripotent stem cells (iPSC) in 2006 provided a new platform for modelling human disorders of the central nervous system (CNS). The ability to produce patient- and disease-specific iPSC lines has created a new age of disease modelling. Human iPSC may be derived from adult somatic cells and subsequently patterned into numerous distinct cell types. The ability to derive defined and regionalized neural populations from iPSC provides a powerful in vitro model of CNS disorders. This article is part of the theme issue ‘Designer human tissue: coming to a lab near you’.

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Efforts to enhance blood stem cell engraftment: Recent insights from zebrafish hematopoiesis

Journal of Experimental Medicine ◽

10.1084/jem.20171069 ◽

2017 ◽

Vol 214 (10) ◽

pp. 2817-2827 ◽

Cited By ~ 17

Author(s):

Julie R. Perlin ◽

Anne L. Robertson ◽

Leonard I. Zon

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Pluripotent Stem Cells ◽

Hematological Malignancies ◽

Cell Types ◽

Patient Specific ◽

Hematopoietic Stem ◽

Cell Engraftment ◽

Induced Pluripotent

Hematopoietic stem cell transplantation (HSCT) is an important therapy for patients with a variety of hematological malignancies. HSCT would be greatly improved if patient-specific hematopoietic stem cells (HSCs) could be generated from induced pluripotent stem cells in vitro. There is an incomplete understanding of the genes and signals involved in HSC induction, migration, maintenance, and niche engraftment. Recent studies in zebrafish have revealed novel genes that are required for HSC induction and niche regulation of HSC homeostasis. Manipulation of these signaling pathways and cell types may improve HSC bioengineering, which could significantly advance critical, lifesaving HSCT therapies.

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Preferential Lineage-Specific Differentiation of Osteoblast-Derived Induced Pluripotent Stem Cells into Osteoprogenitors

Stem Cells International ◽

10.1155/2017/1513281 ◽

2017 ◽

Vol 2017 ◽

pp. 1-15 ◽

Cited By ~ 7

Author(s):

Casey L. Roberts ◽

Silvia S. Chen ◽

Angela C. Murchison ◽

Rebecca A. Ogle ◽

Michael P. Francis ◽

...

Keyword(s):

Stem Cells ◽

Induced Pluripotent Stem Cells ◽

Pluripotent Stem Cells ◽

Cell Types ◽

Embryoid Bodies ◽

Population Doubling ◽

Specific Cell ◽

Germ Layer ◽

Induced Pluripotent ◽

Endodermal Cells

While induced pluripotent stem cells (iPSCs) hold great clinical promise, one hurdle that remains is the existence of a parental germ-layer memory in reprogrammed cells leading to preferential differentiation fates. While it is problematic for generating cells vastly different from the reprogrammed cells’ origins, it could be advantageous for the reliable generation of germ-layer specific cell types for future therapeutic use. Here we use human osteoblast-derived iPSCs (hOB-iPSCs) to generate induced osteoprogenitors (iOPs). Osteoblasts were successfully reprogrammed and demonstrated by endogenous upregulation of Oct4, Sox2, Nanog, TRA-1-81, TRA-16-1, SSEA3, and confirmatory hPSC Scorecard Algorithmic Assessment. The hOB-iPSCs formed embryoid bodies with cells of ectoderm and mesoderm but have low capacity to form endodermal cells. Differentiation into osteoprogenitors occurred within only 2–6 days, with a population doubling rate of less than 24 hrs; however, hOB-iPSC derived osteoprogenitors were only able to form osteogenic and chondrogenic cells but not adipogenic cells. Consistent with this, hOB-iOPs were found to have higher methylation of PPARγbut similar levels of methylation on the RUNX2 promoter. These data demonstrate that iPSCs can be generated from human osteoblasts, but variant methylation patterns affect their differentiation capacities. Therefore, epigenetic memory can be exploited for efficient generation of clinically relevant quantities of osteoprogenitor cells.

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